├── .gitignore ├── LICENSE ├── README.md ├── _config.yml ├── doc ├── logo-mthread.png └── logo.png ├── many-one ├── Makefile ├── README.md ├── data │ ├── 1.txt │ ├── 2.txt │ └── 3.txt ├── docs │ ├── doxy-config │ ├── logo.png │ └── many-to-one.png ├── include │ ├── interrupt.h │ ├── mangle.h │ ├── mthread.h │ ├── queue.h │ ├── stack.h │ ├── types.h │ └── utils.h ├── run_tests.sh ├── src │ ├── attr.c │ ├── interrupt.c │ ├── mthread.c │ ├── queue.c │ ├── spin_lock.c │ ├── stack.c │ └── utils.c ├── test │ ├── detach_state_test.c │ ├── matrix_test.c │ ├── robust_test.c │ └── spin_test.c └── valgrind.sh └── one-one ├── Makefile ├── README.md ├── docs ├── doxy-config ├── logo.png └── one-to-one.png ├── include ├── mthread.h ├── queue.h ├── stack.h ├── types.h └── utils.h ├── run_tests.sh ├── src ├── attr.c ├── cond.c ├── mthread.c ├── mutex.c ├── queue.c ├── sem.c ├── spin_lock.c ├── stack.c └── utils.c ├── test ├── condvar_test.c ├── mutex_test.c ├── performance_test.c ├── philosophers.c ├── robust_test.c ├── semaphore_test.c └── spin_test.c └── valgrind.sh /.gitignore: -------------------------------------------------------------------------------- 1 | # Ignore local resources 2 | Resources/ 3 | many-one/bin/ 4 | many-one/obj/*.o 5 | one-one/bin/ 6 | one-one/obj/*.o -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | GNU GENERAL PUBLIC LICENSE 2 | Version 3, 29 June 2007 3 | 4 | Copyright (C) 2007 Free Software Foundation, Inc. 5 | Everyone is permitted to copy and distribute verbatim copies 6 | of this license document, but changing it is not allowed. 7 | 8 | Preamble 9 | 10 | The GNU General Public License is a free, copyleft license for 11 | software and other kinds of works. 12 | 13 | The licenses for most software and other practical works are designed 14 | to take away your freedom to share and change the works. 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Interpretation of Sections 15 and 16. 613 | 614 | If the disclaimer of warranty and limitation of liability provided 615 | above cannot be given local legal effect according to their terms, 616 | reviewing courts shall apply local law that most closely approximates 617 | an absolute waiver of all civil liability in connection with the 618 | Program, unless a warranty or assumption of liability accompanies a 619 | copy of the Program in return for a fee. 620 | 621 | END OF TERMS AND CONDITIONS 622 | 623 | How to Apply These Terms to Your New Programs 624 | 625 | If you develop a new program, and you want it to be of the greatest 626 | possible use to the public, the best way to achieve this is to make it 627 | free software which everyone can redistribute and change under these terms. 628 | 629 | To do so, attach the following notices to the program. It is safest 630 | to attach them to the start of each source file to most effectively 631 | state the exclusion of warranty; and each file should have at least 632 | the "copyright" line and a pointer to where the full notice is found. 633 | 634 | 635 | Copyright (C) 636 | 637 | This program is free software: you can redistribute it and/or modify 638 | it under the terms of the GNU General Public License as published by 639 | the Free Software Foundation, either version 3 of the License, or 640 | (at your option) any later version. 641 | 642 | This program is distributed in the hope that it will be useful, 643 | but WITHOUT ANY WARRANTY; without even the implied warranty of 644 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 645 | GNU General Public License for more details. 646 | 647 | You should have received a copy of the GNU General Public License 648 | along with this program. If not, see . 649 | 650 | Also add information on how to contact you by electronic and paper mail. 651 | 652 | If the program does terminal interaction, make it output a short 653 | notice like this when it starts in an interactive mode: 654 | 655 | Copyright (C) 656 | This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. 657 | This is free software, and you are welcome to redistribute it 658 | under certain conditions; type `show c' for details. 659 | 660 | The hypothetical commands `show w' and `show c' should show the appropriate 661 | parts of the General Public License. Of course, your program's commands 662 | might be different; for a GUI interface, you would use an "about box". 663 | 664 | You should also get your employer (if you work as a programmer) or school, 665 | if any, to sign a "copyright disclaimer" for the program, if necessary. 666 | For more information on this, and how to apply and follow the GNU GPL, see 667 | . 668 | 669 | The GNU General Public License does not permit incorporating your program 670 | into proprietary programs. If your program is a subroutine library, you 671 | may consider it more useful to permit linking proprietary applications with 672 | the library. If this is what you want to do, use the GNU Lesser General 673 | Public License instead of this License. But first, please read 674 | . -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 |

2 | 3 |

4 | 5 | [![GitHub issues](https://img.shields.io/github/issues/mayank-02/multithreading-library)](https://github.com/mayank-02/multithreading-library) 6 | ![Contributions welcome](https://img.shields.io/badge/contributions-welcome-green.svg) 7 | [![License](https://img.shields.io/github/license/mayank-02/multithreading-library)](https://opensource.org/licenses/GPL-3.0) 8 | 9 | A lightweight C library based on one-one and many-one model for threading. 10 | 11 | ## Contents 12 | 13 | + [Building](#building) 14 | + [Using mthread in your project](#using-mthread-in-your-project) 15 | + [Usage and examples](#usage-and-examples) 16 | + [API documentation](#api-documentation) 17 | + [Running tests](#running-tests) 18 | + [Time and space complexity](#time-and-space-complexity) 19 | + [Development and contributing](#development-and-contributing) 20 | + [Acknowledgements](#acknowledgements) 21 | 22 | ## Building 23 | 24 | mthread uses make to build libraries (static and shared) and binaries (for tests). 25 | Execute following commands to build mthread using make: 26 | 27 | ``` bash 28 | make 29 | ``` 30 | 31 | This will create binaries in `bin/` directory and libraries (static and shared) in the current directory. 32 | 33 | Optionally, you can run `sudo make install` to install mthread library on your machine (on Linux, this will usually install it to `usr/local/lib` and `usr/local/include`). 34 | 35 | ## Using mthread in your project 36 | 37 | You can use mthread in you project by either directly copying header and source files from [one-one/](one-one/), or by linking mthread library (see [Building](#building) for instructions how to build mthread libraries). 38 | In any case, only thing that you have to do in your source files is to include `mthread.h`. 39 | 40 | To get you started quickly, let's take a look at a few ways to get a simple Hello World project working. 41 | 42 | Our Hello World project has just one source file, `example.c` file, and it looks like this: 43 | 44 | ```c 45 | #include 46 | #include "mthread.h" 47 | 48 | void worker(void) { 49 | printf("Hello World!\n"); 50 | mthread_exit(NULL); 51 | } 52 | 53 | int main() { 54 | mthread_t tid; 55 | mthread_init(); 56 | mthread_create(&tid, NULL, worker, NULL); 57 | mthread_join(tid, NULL); 58 | return 0; 59 | } 60 | ``` 61 | 62 | ### Approach #1: Copying mthread header file and static library 63 | 64 | Instead of copying mthread source files, you could copy the static library or a shared object (check [Building](#building) on how to create static library / shared object). We also need to copy mthread header files. We get following project structure: 65 | In case of a static library: 66 | 67 | ``` 68 | example.c -> your program 69 | mthread.h -> copied from mthread 70 | libmthread.a -> copied from mthread 71 | ``` 72 | 73 | In case of shared object: 74 | 75 | ``` 76 | example.c -> your program 77 | mthread.h -> copied from mthread 78 | libmthread.so -> copied from mthread 79 | ``` 80 | 81 | Now you can compile it with 82 | 83 | ```bash 84 | gcc example.c -o example -L. -llibmthread. 85 | ``` 86 | 87 | ### Approach #2: Install mthread library on machine (TODO) 88 | 89 | Alternatively, you could avoid copying any mthread files and instead install libraries by running `sudo make install` (check [Building](#building)). Now, all you have to do to compile your project is `gcc example.c -o example -llibmthread`. 90 | If you get error message like `cannot open shared object file: No such file or directory`, make sure that your linker includes path where mthread was installed. 91 | 92 | ## Usage and examples 93 | 94 | To know more about how to use mthread library, check out the various tests written in the `test` directory of each model. 95 | 96 | ## API documentation 97 | 98 | + Types are named **mthread\_[type]\_t** (examples: mthread_t, mthread_cond_t, etc.) 99 | 100 | + Functions are called **mthread\_[type]\_[action]** with a few exceptions that are mthread_[action] and pertain to the API in whole and not a specific type. 101 | + Constants are named **MTHREAD\_[NAME]** 102 | 103 | The mthreads API is inherently simple. Not in the sense that it makes multi-threaded (MT) programming a breeze (I doubt this is possible), but in the sense that it provides everything that's needed to write MT programs, and only that. 104 | 105 | To generate the latest API documentation yourself from the source, you need to have [doxygen](www.doxygen.org) installed. 106 | Position yourself in the root directory of the model you are interested in. 107 | Then run `make docs`. This will output a `/docs/html` and `/docs/latex` folder. 108 | Then open `docs/html/index.html` file with your favorite browser. 109 | 110 | Alternatively, you can directly check [mthread.h](one-one/include/mthread.h) for one-one and [mthread.h](many-one/include/mthread.h) for many-one 111 | 112 | ## Running tests 113 | 114 | Check [Building](#building) to see how to build binaries. 115 | To run each test, just run `./run_tests` from the root directory of both models. 116 | Default values are used for tests requiring command line arguments. 117 | 118 | ## Time and space complexity 119 | 120 | The library maintains a queue for internal book keeping. Thus, the functions have different time complexities. They have a best case time complexity of `O(1)` and worst case time complexity of `O(N)`, N being the number of threads spawned. Space complexity is `O(N)`. 121 | 122 | ## Implementation Details 123 | 124 | + To know the implementation details of one-one threading model, please check out it's [README](one-one/README.md) 125 | 126 | + To know the implementation details of many-one threading model, please check out it's [README](many-one/README.md) 127 | 128 | ## Development and contributing 129 | 130 | Feel free to send pull requests and raise issues. 131 | -------------------------------------------------------------------------------- /_config.yml: -------------------------------------------------------------------------------- 1 | theme: jekyll-theme-cayman -------------------------------------------------------------------------------- /doc/logo-mthread.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/mayank-02/multithreading-library/3df2df3068c80851103e1d910e0d21b5ac8918ff/doc/logo-mthread.png -------------------------------------------------------------------------------- /doc/logo.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/mayank-02/multithreading-library/3df2df3068c80851103e1d910e0d21b5ac8918ff/doc/logo.png -------------------------------------------------------------------------------- /many-one/Makefile: -------------------------------------------------------------------------------- 1 | SRC_DIR := src 2 | OBJ_DIR := obj 3 | TEST_DIR := test 4 | BIN_DIR := bin 5 | DOC_DIR := docs 6 | 7 | SRC := $(wildcard $(SRC_DIR)/*.c) 8 | # $(info SRC is $(SRC)) 9 | 10 | OBJ := $(SRC:$(SRC_DIR)/%.c=$(OBJ_DIR)/%.o) 11 | # $(info OBJ is $(OBJ)) 12 | 13 | TEST_SRC := $(wildcard $(TEST_DIR)/*.c) 14 | # $(info TEST_SRC is $(TEST_SRC)) 15 | 16 | TEST_OBJ := $(TEST_SRC:$(TEST_DIR)/%.c=$(TEST_DIR)/%.o) 17 | # $(info TEST_OBJ is $(TEST_OBJ)) 18 | 19 | EXE := $(addprefix $(BIN_DIR)/, $(notdir $(basename $(TEST_SRC)))) 20 | # $(info EXE is $(EXE)) 21 | 22 | CPPFLAGS := -I include 23 | CFLAGS := -g -Wall -fpic 24 | # -g : For debugging purposes 25 | # -Wall : Print all warnings 26 | # -fpic : Use Position Independent Code. It means that the generated machine code is not dependent on being located at a specific address in order to work Ex. Jumps would be generated as relative rather than absolute 27 | TESTCFLAGS := -Wno-int-to-pointer-cast -Wno-pointer-to-int-cast -Wno-return-type 28 | LIB := libmthread.a 29 | LIBSO := libmthread.so 30 | LDFLAGS := -L. 31 | LDLIBS := -lm 32 | 33 | CC := gcc 34 | AR := /usr/bin/ar 35 | RANLIB := /usr/bin/ranlib 36 | .PHONY: all clean lib exe docs 37 | 38 | DEBUG := 0 39 | ifeq ($(DEBUG),1) 40 | CFLAGS += -DDEBUG 41 | endif 42 | 43 | all: $(LIB) $(EXE) $(LIBSO) 44 | 45 | $(LIBSO) : $(OBJ) 46 | $(CC) -shared $(OBJ) -o $@ 47 | 48 | $(LIB) : $(OBJ) 49 | $(AR) rcs $(LIB) $(OBJ) 50 | $(RANLIB) $(LIB) 51 | 52 | $(OBJ_DIR)/%.o: $(SRC_DIR)/%.c | $(OBJ_DIR) 53 | $(CC) $(CPPFLAGS) $(CFLAGS) -c $< -o $@ 54 | 55 | $(BIN_DIR)/%: $(TEST_DIR)/%.o $(LIB) 56 | $(CC) $(LDFLAGS) $^ $(LDLIBS) -o $@ 57 | 58 | $(TEST_DIR)/%.o: $(TEST_DIR)/%.c | $(OBJ_DIR) 59 | $(CC) $(CPPFLAGS) $(CFLAGS) $(TESTCFLAGS) -c $< -o $@ 60 | 61 | $(OBJ_DIR): 62 | mkdir $@ 63 | 64 | docs: 65 | doxygen $(DOC_DIR)/doxy-config 66 | 67 | clean: 68 | $(RM) -rf $(OBJ) $(TEST_OBJ) $(LIB) $(LIBSO) $(EXE) $(DOC_DIR)/html $(DOC_DIR)/latex -------------------------------------------------------------------------------- /many-one/README.md: -------------------------------------------------------------------------------- 1 | # Many-One Threading Model 2 | 3 | ![Many to One Threading Model](./docs/many-to-one.png) 4 | 5 | ## Thread Library Initialisation 6 | 7 | + `mthread_init()` initializes the mthread library. It has to be the first mthread API function call in an application, and is mandatory. It's usually done at the begin of the `main()` function of the application. This implicitly initialises the data structures and transforms the single execution unit of the current process into a thread (the 'main' thread). It returns 0 on success. 8 | 9 | ## Thread Creation 10 | 11 | + In the many-to-one model all user level threads execute on the same kernel thread. The process can only run one user-level thread at a time because there is only one kernel-level thread associated with the process. The kernel has no knowledge of user-level threads. 12 | 13 | + To store information about a single thread, a thread control block (TCB) holding information about the state of the thread (its set of registers), information about its stack (a pointer to the thread's stack area and size), and the status of the thread (whether it is running, ready to run, or has exited) is used. Since there will be multiple threads active at the same time, the thread control blocks are stored in a FIFO queue. On creation of the every thread using `mthread_create()`, a TCB is allocated and initialized accordingly. 14 | 15 | + The new user level thread terminates in one of the following ways: 16 | + It calls `mthread_exit()`, specifying an exit status value that is available to another thread in the same process that calls `mthread_join()`. 17 | + It returns from `start_routine()`. This is equivalent to calling `mthread_exit()` with the value supplied in the return statement. 18 | + Any of the threads in the process calls `exit(3)`, or the main thread performs a return from `main()`. This causes the termination of all threads in the process. 19 | 20 | + Therefore, we write a wrapper function - `mthread_start()` which grabs the argument from the TCB and then invoke the actual start function, passing it the required argument. In addition, we simply invoke `mthread_exit()` after the thread returns from the previous call to the start function with the result. For this indirection, we need to make the program counter (EIP) point to this function instead of the actual start function. For this, we manually change the **JB_PC** of the `jmpbuf` array. 21 | 22 | + We allocate the memory that is to be used for the thread's stack using `mmap(2)` rather than `malloc(3)` because `mmap(2)` allocates a block of memory that starts on a page boundary and is a multiple of the page size. This is useful sicne we want to establish a guard page (a page with protection PROT_NONE) at the end of the stack using `mprotect(2)`. 23 | 24 | + The stack pointer passed to the stack pointer of the `jmpbuf` structure must reference the top of the stack, since on most processors the stack grows down. This is done by adding the size of the region to the base of the mmap'ed region. To avoid a memory leak, the stack must be freed once the thread has exited. 25 | 26 | + Linux systems are usually equipped with a libc that includes a security feature to protect the addresses stored in jump buffers. This security feature "mangles" (i.e. encrypts) a pointer before saving it in a `jmp_buf`. Thus, we also have to mangle our new stack pointer and program counter before we can write it into a jump buffer, otherwise decryption (and subsequent uses) will fail. To mangle a pointer before writing it into the jump buffer, we make use of the `mangle` function. 27 | 28 | + To change attributes of a thread like the stack size, stack base, name for user level debugging and it's detach state, an attribute object of threads passed as the second argument to `mthread_create()`. The user allocates it, and then calls `mthread_attr_init` to intialize it and `mthread_attr_destroy` to clean it up. For more info, refer thread attribute handling. 29 | 30 | + On succesful thread creation, the thread library provides a **thread handle** as a return value which can be further used in different thread control functions. 31 | 32 | ## Scheduling 33 | 34 | + A hybrid model between cooperative and preemptive scheduling is implemented where a running thread may `mthread_yield()` or be preempted by a timer. 35 | 36 | + Once multiple threads are running, to switch between different threads we use the library functions `sigsetjmp(3)` and `siglongjmp(3)`. In a nutshell, `sigsetjmp` saves the current state of a thread into a `jmp_buf` structure. `siglongjmp` uses this structure to restore (jump back) to a previously saved state. More precisely, we have the currently executing thread call `sigsetjmp(3)` and save the result in the thread's TCB. Then, our scheduler can pick another thread, and use the saved `jmp_buf` of that thread together with `siglongjmp(3)` to resume the execution of the new thread. 37 | 38 | + The process of picking another thread is called scheduling. In our system, we have a very simply scheduler. Just cycle through the available threads in a round robin fashion, giving an equal, fair share to each thread. 39 | 40 | + To periodically switch to the next user level thread, we make use of signals. More precisely, we use the `setitimer` function to set up a periodic timer that sends a `SIGVTALRM` signal every X milliseconds (here, X is 10ms). When the timer expires the kernel will send a signal to the process. The scheduler is registered as a signal handler for the timer signal. 41 | 42 | ## Thread Attribute Handling 43 | 44 | Attribute objects are used in mthread to store attributes for to be spawned threads. They are stand-alone/unbound attribute objects i.e. they cannot modify attributes of existing threads. The following attribute fields exists in attribute objects: 45 | 46 | + MTHREAD_ATTR_NAME (read-write) [char *] 47 | Name of thread (up to 64 characters are stored only), mainly for debugging purposes. 48 | 49 | + MTHREAD_ATTR_JOINABLE (read-write) \[int\] 50 | The thread detachment type, JOINABLE indicates a joinable thread, DETACHED indicates a detached thread. 51 | 52 | + MTHREAD_ATTR_STACK_SIZE (read-write) \[unsigned int\] 53 | The thread stack size in bytes. Use lower values with great care! 54 | 55 | + MTHREAD_ATTR_STACK_ADDR (read-write) \[char *\] 56 | A pointer to the lower address of a chunk of malloc(3)'ed memory for the stack. 57 | 58 | `mthread_attr_t mthread_attr_new(void);` 59 | This returns a new unbound attribute object. An implicit mthread_attr_init() is done on it. Any queries on this object just fetch stored attributes from it. And attribute modifications just change the stored attributes. Use such attribute objects to pre-configure attributes for to be spawned threads. 60 | 61 | `int mthread_attr_init(mthread_attr_t attr);` 62 | This initializes an attribute object attr to the default values: 63 | MTHREAD_ATTR_NAME := 'Unknown', MTHREAD_ATTR_JOINABLE := JOINABLE, MTHREAD_ATTR_STACK_SIZE := DEFAULT and MTHREAD_ATTR_STACK_ADDR := NULL. 64 | 65 | `int mthread_attr_set(mthread_attr_t attr, int field, ...);` 66 | This sets the attribute field in attr to a value specified as an additional argument on the variable argument list. The following attribute fields and argument pairs can be used: 67 | 68 | | Attribute | Type | 69 | |---------------------------|--------------| 70 | | MTHREAD_ATTR_NAME | char * | 71 | | MTHREAD_ATTR_JOINABLE | int | 72 | | MTHREAD_ATTR_STACK_SIZE | unsigned int | 73 | | MTHREAD_ATTR_STACK_ADDR | void * | 74 | 75 | `int mthread_attr_get(mthread_attr_t attr, int field, ...);` 76 | This retrieves the attribute field in attr and stores its value in the variable specified through a pointer in an additional argument on the variable argument list. The following fields and argument pairs can be used: 77 | 78 | | Attribute | Type | 79 | |---------------------------|---------------| 80 | | MTHREAD_ATTR_NAME | char ** | 81 | | MTHREAD_ATTR_JOINABLE | int * | 82 | | MTHREAD_ATTR_STACK_SIZE | unsigned int *| 83 | | MTHREAD_ATTR_STACK_ADDR | void ** | 84 | 85 | `int mthread_attr_destroy(mthread_attr_t attr);` 86 | This destroys a attribute object attr. After this attr is no longer a valid attribute object. 87 | 88 | ## Thread Joining 89 | 90 | + The `mthread_join()` function waits for the thread specified by thread to terminate. If that thread has already terminated, then `mthread_join()` returns immediately. The thread specified by thread must be joinable. 91 | 92 | + A thread may have to wait for the completion of another thread. If the caller thread waits for an incomplete target thread to join, then it will halt till the target thread exits. This is done by changing the state of the thread to WAITING. Once the target thread has finished, the current thread will be signaled and it's state will be changed to READY again. 93 | 94 | + Even if a thread has finished execution, none of its allocated resources are freed. The resources of the thread are released only after the program exits to improve time complexity. 95 | 96 | + A thread must be joined on only once. Any further joins on an already joined thread will return errors. 97 | 98 | + All of the threads in a process are peers: any thread can join with any other thread in the process. 99 | 100 | ## Thread Signals 101 | 102 | + Signals may be sent to a specific thread using `mthread_kill()`. 103 | 104 | + All signals which aren't meant for the current thread are made pending for that thread. They are raised when the thread is scheduled. 105 | 106 | + Note : Signal dispositions and actions are process-wide: if an unhandled signal is delivered to a thread, then it will affect (terminate, stop, continue, be ignored in) all members of the thread group. 107 | 108 | ## Thread Exiting 109 | 110 | + As mentioned previously, a thread can exit using the `mthread_exit()` function. The thread can also return a value while it is exiting, to be returned to the thread joining on it. This is done by storing it's result in the TCB and marking the state of the thread as FINISHED. 111 | 112 | + Any threads joined on the thread exiting are signaled the about the completion of this thread. 113 | 114 | ## Thread Yielding 115 | 116 | + Yield execution control to next thread by simply calling `mthread_yield()`. It is simply a wrapper for a `raise(SIGVTALRM)` 117 | 118 | ## Thread Detachment 119 | 120 | + The `mthread_detach()` function marks the thread passed as argument as detached. Any other thread trying to join on a detached thread will result in an error. 121 | 122 | ## Thread Equality 123 | 124 | + The `mthread_equal()` function checks whether the threads identified by their thread handles are the same or not. Returns 0 if equal and non-zero if not. 125 | 126 | ## Synchronisation Primitives 127 | 128 | ## Spinlocks 129 | 130 | A spinlock is a lock which causes a thread trying to acquire it to simply wait in a loop ("spin") while repeatedly checking if the lock is available. The advantage of a spinlock is that the thread is kept active and does not enter a sleep-wait for a mutex to become available, thus can perform better in certain cases than typical blocking-sleep-wait style mutexes. 131 | 132 | Functions used in conjunction with the spinlock: 133 | 134 | Creating/Destroying: 135 | `mthread_spinlock_init()` 136 | `mthread_spinlock_destroy()` 137 | 138 | Attempt to lock the spinlock (returns immediately with EBUSY if locked): 139 | `mthread_spinlock_trylock()` 140 | 141 | Lock the spinlock (blocks until spinlock is unlocked): 142 | `mthread_spinlock_lock()` 143 | 144 | Unlock the spinlock: 145 | `mthread_spinlock_unlock()` 146 | -------------------------------------------------------------------------------- /many-one/data/1.txt: -------------------------------------------------------------------------------- 1 | 3 3 2 | 1 2 4 3 | 4 2 3 4 | 6 5 8 5 | 3 3 6 | 5 8 4 7 | 4 1 3 8 | 3 2 5 -------------------------------------------------------------------------------- /many-one/data/2.txt: -------------------------------------------------------------------------------- 1 | 11 11 2 | 22 78 95 32 29 85 60 19 92 14 8 3 | 85 38 57 49 89 46 15 56 85 53 33 4 | 36 60 19 27 4 6 57 83 94 79 13 5 | 41 63 43 27 76 14 71 90 22 8 81 6 | 31 10 70 78 25 26 15 30 11 51 43 7 | 30 78 47 88 87 82 35 67 96 28 30 8 | 91 7 58 5 79 49 79 87 30 62 97 9 | 0 40 75 26 55 57 89 6 0 20 37 10 | 0 60 24 82 95 43 78 76 26 69 83 11 | 84 26 62 33 57 2 15 20 51 15 12 12 | 78 93 68 36 83 26 36 55 15 36 67 13 | 11 11 14 | 5 99 43 58 79 0 0 75 46 7 25 15 | 34 36 4 40 36 67 24 66 11 1 37 16 | 51 89 96 76 4 75 14 65 22 71 64 17 | 17 29 95 18 81 22 16 88 99 50 76 18 | 3 43 64 71 67 31 34 21 20 85 10 19 | 16 13 66 44 79 31 66 50 47 84 32 20 | 94 54 13 16 22 54 67 24 30 71 67 21 | 95 94 87 78 28 60 50 13 22 66 78 22 | 88 10 57 71 29 59 70 65 91 64 19 23 | 57 32 93 63 99 17 45 70 37 92 16 24 | 76 22 44 36 72 9 58 91 87 98 1 25 | -------------------------------------------------------------------------------- /many-one/docs/logo.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/mayank-02/multithreading-library/3df2df3068c80851103e1d910e0d21b5ac8918ff/many-one/docs/logo.png -------------------------------------------------------------------------------- /many-one/docs/many-to-one.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/mayank-02/multithreading-library/3df2df3068c80851103e1d910e0d21b5ac8918ff/many-one/docs/many-to-one.png -------------------------------------------------------------------------------- /many-one/include/interrupt.h: -------------------------------------------------------------------------------- 1 | #ifndef _INTERRUPT_H_ 2 | #define _INTERRUPT_H_ 3 | 4 | #include 5 | 6 | /// Timer interval 7 | #define TIMER (suseconds_t) 10000 8 | 9 | typedef struct itimerval mthread_timer_t; 10 | 11 | void interrupt_enable(mthread_timer_t *timer); 12 | 13 | void interrupt_disable(mthread_timer_t *timer); 14 | 15 | #endif -------------------------------------------------------------------------------- /many-one/include/mangle.h: -------------------------------------------------------------------------------- 1 | #ifndef _MANGLE_H_ 2 | #define _MANGLE_H_ 3 | 4 | #ifdef __x86_64__ 5 | /* Pointer mangling for 64 bit Intel architecture */ 6 | #define JB_SP 6 7 | #define JB_PC 7 8 | static long int mangle(long int p) { 9 | long int ret; 10 | asm(" mov %1, %%rax;\n" 11 | " xor %%fs:0x30, %%rax;" 12 | " rol $0x11, %%rax;" 13 | " mov %%rax, %0;" 14 | : "=r"(ret) 15 | : "r"(p) 16 | : "%rax" 17 | ); 18 | return ret; 19 | } 20 | #else 21 | /* Pointer mangling for 32 bit Intel architecture */ 22 | #define JB_SP 4 23 | #define JB_PC 5 24 | static unsigned int mangle(unsigned int addr) { 25 | unsigned int ret ; 26 | asm volatile("xor %%gs:0x18,%0\n" 27 | "rol $0x9,%0\n" 28 | : "=g" (ret) 29 | : "0" (addr)); 30 | return ret; 31 | } 32 | #endif 33 | 34 | #endif -------------------------------------------------------------------------------- /many-one/include/mthread.h: -------------------------------------------------------------------------------- 1 | #ifndef _MTHREAD_H_ 2 | #define _MTHREAD_H_ 3 | 4 | #include "types.h" 5 | 6 | enum { 7 | DETACHED, 8 | JOINABLE, 9 | }; 10 | 11 | /// Operation to perform on thread attribute structure 12 | enum { 13 | MTHREAD_ATTR_GET, 14 | MTHREAD_ATTR_SET 15 | }; 16 | 17 | /// Attribute to read/write in thread attribute structure 18 | enum { 19 | MTHREAD_ATTR_NAME, /* RW [char *] name of thread */ 20 | MTHREAD_ATTR_JOINABLE, /* RW [int] detachment type */ 21 | MTHREAD_ATTR_STACK_SIZE, /* RW [size_t] stack */ 22 | MTHREAD_ATTR_STACK_ADDR /* RW [void *] stack lower */ 23 | }; 24 | 25 | /* Thread attribute functions */ 26 | struct mthread_attr; 27 | typedef struct mthread_attr mthread_attr_t; 28 | 29 | mthread_attr_t *mthread_attr_new(void); 30 | int mthread_attr_init(mthread_attr_t *attr); 31 | int mthread_attr_set(mthread_attr_t *attr, int field, ...); 32 | int mthread_attr_get(mthread_attr_t *attr, int field, ...); 33 | int mthread_attr_destroy(mthread_attr_t *attr); 34 | 35 | /** 36 | * Perform any initialization needed. Should be called exactly 37 | * once, before any other mthread functions. 38 | */ 39 | int mthread_init(void); 40 | 41 | /** 42 | * Create a new thread starting at the routine given, which will 43 | * be passed arg. The new thread does not execute immediatly. 44 | */ 45 | int mthread_create(mthread_t *thread, const mthread_attr_t *attr, void *(*start_routine)(void *), void *arg); 46 | 47 | /** 48 | * Wait until the specified thread has exited. 49 | * Returns the value returned by that thread's 50 | * start function. 51 | */ 52 | int mthread_join(mthread_t thread, void **retval); 53 | 54 | /** 55 | * Yield to scheduler 56 | */ 57 | void mthread_yield(void); 58 | 59 | /** 60 | * Exit the calling thread with return value retval. 61 | */ 62 | void mthread_exit(void *retval); 63 | 64 | /** 65 | * Send signal specified by sig to thread 66 | */ 67 | int mthread_kill(mthread_t thread, int sig); 68 | 69 | /** 70 | * Mark the thread as detached 71 | */ 72 | int mthread_detach(mthread_t thread); 73 | 74 | /** 75 | * Compare Thread IDs 76 | */ 77 | int mthread_equal(mthread_t t1, mthread_t t2); 78 | 79 | /* Synchronisation Primitives */ 80 | struct mthread_spinlock; 81 | typedef struct mthread_spinlock mthread_spinlock_t; 82 | 83 | /* 84 | * Initialise the spinlock 85 | */ 86 | int mthread_spin_init(mthread_spinlock_t *lock); 87 | 88 | /* 89 | * Lock the spinlock 90 | */ 91 | int mthread_spin_lock(mthread_spinlock_t *lock); 92 | 93 | /* 94 | * Try locking the spinlock 95 | */ 96 | int mthread_spin_trylock(mthread_spinlock_t *lock); 97 | 98 | /* 99 | * Unlock the spinlock 100 | */ 101 | int mthread_spin_unlock(mthread_spinlock_t *lock); 102 | 103 | #endif -------------------------------------------------------------------------------- /many-one/include/queue.h: -------------------------------------------------------------------------------- 1 | #include "mthread.h" 2 | 3 | /// Node of a queue 4 | typedef struct node { 5 | /// TCB 6 | mthread *thd; 7 | /// Pointer to next node 8 | struct node *next; 9 | } node; 10 | 11 | /// Queue 12 | typedef struct queue { 13 | /// Count of nodes in the queue 14 | int count; 15 | /// Pointer to head node 16 | node *head; 17 | /// Pointer to tail node 18 | node *tail; 19 | } queue; 20 | 21 | void initialize(queue *q); 22 | 23 | int isempty(queue *q); 24 | 25 | void enqueue(queue *q, mthread *thd); 26 | 27 | mthread *dequeue(queue *q); 28 | 29 | int getcount(queue *q); 30 | 31 | void display(queue *q); 32 | 33 | mthread *search_on_tid(queue *q, pid_t tid); 34 | 35 | void destroy(queue *q); -------------------------------------------------------------------------------- /many-one/include/stack.h: -------------------------------------------------------------------------------- 1 | #ifndef _STACK_H_ 2 | #define _STACK_H_ 3 | 4 | size_t get_stack_size(void); 5 | 6 | void * allocate_stack(size_t stack_size); 7 | 8 | int deallocate_stack(void *base, size_t stack_size); 9 | 10 | #endif -------------------------------------------------------------------------------- /many-one/include/types.h: -------------------------------------------------------------------------------- 1 | #ifndef _TYPES_H_ 2 | #define _TYPES_H_ 3 | 4 | #include 5 | #include 6 | #include 7 | #include 8 | /// Maximum threads that can be created 9 | #define MTHREAD_MAX_THREADS 128 10 | 11 | /// Minimum stack for each thread 12 | #define MTHREAD_MIN_STACK 64 * 1024 13 | 14 | /// Maximium length of name of thread 15 | #define MTHREAD_TCB_NAMELEN 128 16 | 17 | /// Default attribute of thread 18 | #define MTHREAD_ATTR_DEFAULT (NULL) 19 | 20 | #define FALSE (0) 21 | #define TRUE (!FALSE) 22 | 23 | /// States of a thread 24 | typedef enum mthread_state { 25 | RUNNING = 0, 26 | READY, 27 | FINISHED, 28 | WAITING 29 | } mthread_state_t; 30 | 31 | /// Thread Handle 32 | typedef pid_t mthread_t; 33 | 34 | /// Thread Control Block 35 | typedef struct mthread { 36 | /// Thread ID 37 | mthread_t tid; 38 | 39 | /// Thread State 40 | mthread_state_t state; 41 | 42 | /// Start position of the code to be executed 43 | void *(*start_routine) (void *); 44 | 45 | /// Argument passed to the function 46 | void *arg; 47 | 48 | /// Result of the thread function 49 | void *result; 50 | 51 | /// Stack Base 52 | void *stackaddr; 53 | 54 | /// Stack Size 55 | size_t stacksize; 56 | 57 | /// Context of the thread 58 | sigjmp_buf context; 59 | 60 | /// Name for debugging 61 | char name[MTHREAD_TCB_NAMELEN]; 62 | 63 | /// Detachment type 64 | int joinable; 65 | 66 | /// TID to be joined to once finished 67 | mthread_t joined_on; 68 | 69 | /// For signal handling 70 | sigset_t sigpending; 71 | } mthread; 72 | 73 | /// Thread Attribute Structure 74 | struct mthread_attr { 75 | /// Name for debugging 76 | char a_name[MTHREAD_TCB_NAMELEN]; 77 | 78 | /// Detachment type 79 | int a_joinable; 80 | 81 | /// Stack Base 82 | void *a_stackaddr; 83 | 84 | /// Stack Size 85 | size_t a_stacksize; 86 | }; 87 | 88 | /// States of a spinlock 89 | #define LOCKED (1u) 90 | #define UNLOCKED (0u) 91 | 92 | /// Spinlock structure 93 | struct mthread_spinlock { 94 | /// Value of spinlock 95 | int value; 96 | }; 97 | 98 | #endif -------------------------------------------------------------------------------- /many-one/include/utils.h: -------------------------------------------------------------------------------- 1 | #ifndef _UTILS_H_ 2 | #define _UTILS_H_ 3 | 4 | #include 5 | 6 | char *util_strncpy(char *dst, const char *src, size_t dst_size); 7 | 8 | #endif -------------------------------------------------------------------------------- /many-one/run_tests.sh: -------------------------------------------------------------------------------- 1 | #!/bin/bash 2 | 3 | echo -e "\033[34m************************RUNNING ROBUST TEST*************************\033[0m" 4 | echo "./bin/robust_test" 5 | ./bin/robust_test 6 | echo "" 7 | echo "" 8 | echo -e "\033[34m*********************RUNNING DETACH STATE TEST**********************\033[0m" 9 | echo "./bin/detach_state_test" 10 | ./bin/detach_state_test 11 | echo -e "\033[33mCASE: JOINABLE threads, but don't wait\033[0m" 12 | ./bin/detach_state_test n 13 | echo "" 14 | echo "" 15 | echo -e "\033[33mCASE: JOINABLE threads, with mthread_join()\033[0m" 16 | ./bin/detach_state_test j 17 | echo "" 18 | echo "" 19 | echo -e "\033[33mCASE: DETACHED threads, and don't wait\033[0m" 20 | ./bin/detach_state_test d 21 | echo "" 22 | echo "" 23 | echo -e "\033[33mCASE: DETACHED threads, and wait 3 seconds\033[0m" 24 | ./bin/detach_state_test x 25 | echo "" 26 | echo "" 27 | echo -e "\033[34m************************RUNNING MATRIX TEST*************************\033[0m" 28 | echo "./bin/matrix_test <./data/2.txt" 29 | ./bin/matrix_test <./data/2.txt 30 | echo "" 31 | echo "" 32 | echo -e "\033[34m***********************RUNNING SPINLOCK TEST************************\033[0m" 33 | echo "./bin/spin_test 2> /dev/null" 34 | ./bin/spin_test 2> /dev/null 35 | echo "" 36 | echo -e "\033[31mTo disable debug statements, set DEBUG = 0 in Makefile" -------------------------------------------------------------------------------- /many-one/src/attr.c: -------------------------------------------------------------------------------- 1 | /** 2 | * @file attr.c 3 | * @brief Attribute handling functions 4 | * @author Mayank Jain 5 | * @bug No known bugs 6 | */ 7 | 8 | #include 9 | #include 10 | #include 11 | #include 12 | #include "mthread.h" 13 | #include "utils.h" 14 | 15 | /** 16 | * @brief Controls the attributes depending on the operation 17 | * @param[in] cmd Get or Set the attribute 18 | * @param[in,out] a Attribute object 19 | * @param[in] op Attribute 20 | * @param[in] ap Variable argument list corresponding to attribute 21 | * @return On success, returns 0; on error, it returns an error number 22 | */ 23 | static int mthread_attr_ctrl(int cmd, mthread_attr_t *a, int op, va_list ap) { 24 | if(a == NULL) 25 | return EINVAL; 26 | switch(op) { 27 | case MTHREAD_ATTR_NAME: { 28 | /* name */ 29 | if(cmd == MTHREAD_ATTR_SET) { 30 | char *src, *dst; 31 | src = va_arg(ap, char *); 32 | dst = a->a_name; 33 | util_strncpy(dst, src, MTHREAD_TCB_NAMELEN); 34 | } 35 | else { 36 | char *src, **dst; 37 | src = a->a_name; 38 | dst = va_arg(ap, char **); 39 | *dst = src; 40 | } 41 | break; 42 | } 43 | case MTHREAD_ATTR_JOINABLE: { 44 | /* detachment type */ 45 | int val, *src, *dst; 46 | if(cmd == MTHREAD_ATTR_SET) { 47 | src = &val; 48 | val = va_arg(ap, int); 49 | dst = &a->a_joinable; 50 | } 51 | else { 52 | src = &a->a_joinable; 53 | dst = va_arg(ap, int *); 54 | } 55 | *dst = *src; 56 | break; 57 | } 58 | case MTHREAD_ATTR_STACK_SIZE: { 59 | /* stack size */ 60 | size_t val, *src, *dst; 61 | if(cmd == MTHREAD_ATTR_SET) { 62 | src = &val; 63 | val = va_arg(ap, size_t); 64 | dst = &a->a_stacksize; 65 | } 66 | else { 67 | src = &a->a_stacksize; 68 | dst = va_arg(ap, size_t *); 69 | } 70 | *dst = *src; 71 | break; 72 | } 73 | case MTHREAD_ATTR_STACK_ADDR: { 74 | /* stack address */ 75 | void *val, **src, **dst; 76 | if(cmd == MTHREAD_ATTR_SET) { 77 | src = &val; 78 | val = va_arg(ap, void *); 79 | dst = &a->a_stackaddr; 80 | } 81 | else { 82 | src = &a->a_stackaddr; 83 | dst = va_arg(ap, void **); 84 | } 85 | *dst = *src; 86 | break; 87 | } 88 | default: 89 | return EINVAL; 90 | } 91 | return 0; 92 | } 93 | 94 | /** 95 | * @brief Make a new thread attributes object and initialise it 96 | * @return On success, returns pointer to attribute object; 97 | * on error, it returns NULL 98 | */ 99 | mthread_attr_t *mthread_attr_new(void) { 100 | mthread_attr_t *a; 101 | a = (mthread_attr_t *) calloc(1, sizeof(mthread_attr_t)); 102 | if(a == NULL) { 103 | return NULL; 104 | } 105 | 106 | mthread_attr_init(a); 107 | return a; 108 | } 109 | 110 | /** 111 | * @brief Controls the attributes depending on the operation 112 | * @param[in,out] a Attribute object to be initialised 113 | * @return On success, returns 0; on error, it returns an error number 114 | */ 115 | int mthread_attr_init(mthread_attr_t *a) { 116 | if(a == NULL) 117 | return EINVAL; 118 | 119 | util_strncpy(a->a_name, "Unknown", MTHREAD_TCB_NAMELEN); 120 | a->a_joinable = 1; 121 | a->a_stacksize = 64 * 1024; 122 | a->a_stackaddr = NULL; 123 | 124 | return 0; 125 | } 126 | 127 | /** 128 | * @brief Get particular attribute from thread attribute object 129 | * @param[in] a Attribute object 130 | * @param[in] op Attribute 131 | * @param[in] ... Variable argument list corresponding to attribute 132 | * @return On success, returns 0; on error, it returns an error number 133 | */ 134 | int mthread_attr_get(mthread_attr_t *a, int op, ...) { 135 | va_list ap; 136 | int ret; 137 | 138 | va_start(ap, op); 139 | ret = mthread_attr_ctrl(MTHREAD_ATTR_GET, a, op, ap); 140 | va_end(ap); 141 | return ret; 142 | } 143 | 144 | /** 145 | * @brief Set particular attribute in thread attribute object 146 | * @param[in,out] a Attribute object 147 | * @param[in] op Attribute 148 | * @param[in] ... Variable argument list corresponding to attribute 149 | * @return On success, returns 0; on error, it returns an error number 150 | */ 151 | int mthread_attr_set(mthread_attr_t *a, int op, ...) { 152 | va_list ap; 153 | int ret; 154 | 155 | va_start(ap, op); 156 | ret = mthread_attr_ctrl(MTHREAD_ATTR_SET, a, op, ap); 157 | va_end(ap); 158 | return ret; 159 | } 160 | 161 | /** 162 | * @brief Destroy thread attribute 163 | * @param[in,out] a Attribute object 164 | * @return On success, returns 0; on error, it returns an error number 165 | */ 166 | int mthread_attr_destroy(mthread_attr_t *a) { 167 | if(a == NULL) 168 | return EINVAL; 169 | free(a); 170 | return 0; 171 | } -------------------------------------------------------------------------------- /many-one/src/interrupt.c: -------------------------------------------------------------------------------- 1 | /** 2 | * @file interrupt.c 3 | * @brief To handle timers 4 | * @author Mayank Jain 5 | * @bug No known bugs 6 | */ 7 | 8 | #include 9 | #include 10 | #include "interrupt.h" 11 | 12 | /** 13 | * @brief Enable interrupts 14 | * @param[in] timer Pointer to timer 15 | * @note The timer is set for TIMER nanoseconds defined in the header 16 | * @note At each expiration of the timer, a SIGALRM is sent 17 | */ 18 | void interrupt_enable(mthread_timer_t *timer) { 19 | /* Enable timer (counts down in real time) */ 20 | timer->it_value.tv_sec = 0; 21 | timer->it_value.tv_usec = TIMER; 22 | timer->it_interval.tv_sec = 0; 23 | timer->it_interval.tv_usec = TIMER; 24 | setitimer(ITIMER_VIRTUAL, timer, 0); 25 | } 26 | 27 | /** 28 | * @brief Disable interrupts 29 | * @param[in] timer Pointer to timer 30 | */ 31 | void interrupt_disable(mthread_timer_t *timer) { 32 | /* Disable timer */ 33 | timer->it_value.tv_sec = 0; 34 | timer->it_value.tv_usec = 0; 35 | timer->it_interval.tv_sec = 0; 36 | timer->it_interval.tv_usec = 0; 37 | setitimer(ITIMER_VIRTUAL, timer, 0); 38 | } -------------------------------------------------------------------------------- /many-one/src/mthread.c: -------------------------------------------------------------------------------- 1 | /** 2 | * @file mthread.c 3 | * @brief Thread control functions 4 | * @author Mayank Jain 5 | * @bug No known bugs 6 | */ 7 | 8 | #include 9 | #include 10 | #include 11 | #include 12 | #include 13 | #include 14 | #include "mthread.h" 15 | #include "queue.h" 16 | #include "interrupt.h" 17 | #include "mangle.h" 18 | #include "stack.h" 19 | #include "utils.h" 20 | 21 | /** 22 | * @brief For debugging purposes 23 | */ 24 | #ifdef DEBUG 25 | #define dprintf(fmt, ...) \ 26 | do { if (DEBUG) fprintf(stderr, fmt, ##__VA_ARGS__); } while (0) 27 | #else 28 | #define dprintf(fmt, ...) ; 29 | #endif 30 | 31 | static queue *task_q; ///< Queue containing tasks for all threads 32 | static mthread *current; ///< Thread which is running 33 | static pid_t unique = 0; ///< To allocate unique Thread IDs 34 | static mthread_timer_t timer; ///< Timer for periodic SIGVTALRM signals 35 | 36 | /** 37 | * @brief Gets the next ready thread from the task_q 38 | * @return On success, pointer to the thread; on error, NULL is returned 39 | */ 40 | static mthread * get_next_ready_thread(void) { 41 | mthread *runner; 42 | int i = getcount(task_q); 43 | 44 | while(i--) { 45 | runner = dequeue(task_q); 46 | 47 | switch(runner->state) { 48 | case READY: 49 | return runner; 50 | case WAITING: 51 | case FINISHED: 52 | enqueue(task_q, runner); 53 | break; 54 | case RUNNING: 55 | return NULL; 56 | } 57 | } 58 | 59 | return NULL; 60 | } 61 | 62 | /** 63 | * @brief Cleans up all malloc(3)ed and mmap(3)ed regions 64 | */ 65 | static void cleanup_handler(void) { 66 | dprintf("%-15s: Cleaning up data structures\n", "cleanup_handler"); 67 | 68 | mthread *t; 69 | int n = getcount(task_q); 70 | while(n--) { 71 | t = dequeue(task_q); 72 | deallocate_stack(t->stackaddr, t->stacksize); 73 | free(t); 74 | } 75 | free(task_q); 76 | } 77 | 78 | /** 79 | * @brief Wrapper around user start function 80 | * @note It makes an implicit call to mthread_exit() to exit the thread 81 | */ 82 | static void mthread_start(void) { 83 | dprintf("%-15s: Entered with TID %d\n", "mthread_start", current->tid); 84 | current->result = current->start_routine(current->arg); 85 | mthread_exit(current->result); 86 | } 87 | 88 | /** 89 | * @brief Schedules next ready thread 90 | * @param[in] signum Signal number for which this function is a handler 91 | * @note All signals are blocked in the scheduler 92 | */ 93 | static void scheduler(int signum) { 94 | dprintf("%-15s: SIGVTALRM received\n", "scheduler"); 95 | /* Disable timer interrupts when scheduler is running */ 96 | interrupt_disable(&timer); 97 | 98 | /* Save context and signal masks */ 99 | if(sigsetjmp(current->context, 1) == 1) 100 | return; 101 | 102 | dprintf("%-15s: Saving context of Thread TID = %d\n", "scheduler", current->tid); 103 | 104 | /* Change state of current thread from RUNNING to READY*/ 105 | if(current->state == RUNNING) 106 | current->state = READY; 107 | 108 | /* Enqueue current thread to task queue */ 109 | enqueue(task_q, current); 110 | 111 | /* Get next ready thread running */ 112 | current = get_next_ready_thread(); 113 | if(current == NULL) { 114 | /* Exit if no threads left to schedule */ 115 | exit(0); 116 | } 117 | current->state = RUNNING; 118 | 119 | /* Raise all pending signals */ 120 | for(int sig = 1; sig < NSIG; sig++) { 121 | if(sigismember(¤t->sigpending, sig)) { 122 | raise(sig); 123 | sigdelset(¤t->sigpending, sig); 124 | dprintf("%-15s: Raised pending signal %d of TID = %d\n", "scheduler", sig, current->tid); 125 | } 126 | } 127 | /* Enable timer interrupts before loading next thread */ 128 | interrupt_enable(&timer); 129 | 130 | dprintf("%-15s: Loading context of Thread TID = %d\n", "scheduler", current->tid); 131 | /* Load context and signal masks */ 132 | siglongjmp(current->context, 1); 133 | } 134 | 135 | /** 136 | * @brief Initialise the mthread library 137 | * @note It has to be the first mthread API function call in an application, 138 | * and is mandatory. 139 | * @return On success, returns 0; on error, it returns an error number 140 | */ 141 | int mthread_init(void) { 142 | dprintf("%-15s: Started\n", "mthread_init"); 143 | 144 | /* Initialise queues */ 145 | task_q = calloc(1, sizeof(queue)); 146 | initialize(task_q); 147 | 148 | /* Register cleanup handler to be called on exit */ 149 | atexit(cleanup_handler); 150 | 151 | /* Make thread control block for main thread */ 152 | current = (mthread *) calloc(1, sizeof(mthread)); 153 | current->tid = unique++; 154 | current->state = RUNNING; 155 | current->joined_on = -1; 156 | current->start_routine = current->arg = current->result = NULL; 157 | 158 | /* Setting up signal handler */ 159 | struct sigaction setup_action; 160 | sigset_t block_mask; 161 | sigfillset(&block_mask); 162 | setup_action.sa_handler = scheduler; 163 | setup_action.sa_mask = block_mask; 164 | setup_action.sa_flags = 0; 165 | sigaction(SIGVTALRM, &setup_action, NULL); 166 | 167 | /* Setup timer for regular interrupts */ 168 | interrupt_enable(&timer); 169 | 170 | dprintf("%-15s: Exited\n", "mthread_init"); 171 | return 0; 172 | } 173 | 174 | /** 175 | * @brief Create a new thread 176 | * @param[in] thread Pointer to thread handle 177 | * @param[in] attr Pointer to attribute object 178 | * @param[in] start_routine Start function of the thread 179 | * @param[in] arg Arguments to be passed to the start function 180 | * @return On success, returns 0; on error, it returns an error number 181 | */ 182 | int mthread_create(mthread_t *thread, const mthread_attr_t *attr, void *(*start_routine)(void *), void *arg) { 183 | dprintf("%-15s: Started\n", "mthread_create"); 184 | 185 | if(thread == NULL) 186 | return EFAULT; 187 | 188 | if(start_routine == NULL) 189 | return EFAULT; 190 | 191 | if(unique == MTHREAD_MAX_THREADS) 192 | return EAGAIN; 193 | 194 | mthread *tmp = (mthread *) calloc(1, sizeof(mthread)); 195 | if(tmp == NULL) 196 | return EAGAIN; 197 | 198 | interrupt_disable(&timer); 199 | 200 | tmp->tid = unique++; 201 | tmp->state = READY; 202 | tmp->start_routine = start_routine; 203 | tmp->arg = arg; 204 | tmp->joined_on = -1; 205 | sigemptyset(&tmp->sigpending); 206 | 207 | /* Stack handling */ 208 | if(attr != NULL && attr->a_stacksize > MTHREAD_MIN_STACK) 209 | tmp->stacksize = attr->a_stacksize; 210 | else 211 | tmp->stacksize = MTHREAD_MIN_STACK; 212 | 213 | tmp->stackaddr = (attr == NULL ? NULL : attr->a_stackaddr); 214 | if(tmp->stackaddr == NULL) { 215 | tmp->stackaddr = allocate_stack(tmp->stacksize); 216 | if(tmp->stackaddr == NULL) { 217 | interrupt_enable(&timer); 218 | return EAGAIN; 219 | } 220 | } 221 | 222 | /* Configure remaining attributes */ 223 | if(attr != NULL) { 224 | /* Overtake fields from the attribute structure */ 225 | tmp->joinable = attr->a_joinable; 226 | util_strncpy(tmp->name, attr->a_name, MTHREAD_TCB_NAMELEN); 227 | } 228 | else { 229 | /* Set defaults */ 230 | tmp->joinable = TRUE; 231 | snprintf(tmp->name, MTHREAD_TCB_NAMELEN, "User%d", tmp->tid); 232 | } 233 | 234 | /* Make context for new thread */ 235 | sigsetjmp(tmp->context, 1); 236 | 237 | /* Change stack pointer to point to top of stack */ 238 | tmp->context[0].__jmpbuf[JB_SP] = mangle((long int) tmp->stackaddr + tmp->stacksize - sizeof(long int)); 239 | 240 | /* Change program counter to point to start function */ 241 | tmp->context[0].__jmpbuf[JB_PC] = mangle((long int) mthread_start); 242 | 243 | enqueue(task_q, tmp); 244 | *thread = tmp->tid; 245 | 246 | interrupt_enable(&timer); 247 | dprintf("%-15s: Created Thread with TID = %d and put in task queue\n", "mthread_create", tmp->tid); 248 | return 0; 249 | } 250 | 251 | /** 252 | * @brief Join with a terminated thread 253 | * @param[in] tid Handle of thread to wait for 254 | * @param[in] retval To save the exit status of the target thread 255 | * @return On success, returns 0; on error, it returns an error number 256 | */ 257 | int mthread_join(mthread_t tid, void **retval) { 258 | dprintf("%-15s: Thread TID = %d wants to wait on TID = %d\n", "mthread_join", current->tid, tid); 259 | 260 | interrupt_disable(&timer); 261 | mthread *target = search_on_tid(task_q, tid); 262 | 263 | /* Deadlock check */ 264 | if(current->tid == tid) { 265 | interrupt_enable(&timer); 266 | return EDEADLK; 267 | } 268 | 269 | /* Thread exists check */ 270 | if(target == NULL) { 271 | interrupt_enable(&timer); 272 | return ESRCH; 273 | } 274 | 275 | /* Thread is joinable and no one has joined on it check */ 276 | if(!target->joinable || target->joined_on != -1) { 277 | interrupt_enable(&timer); 278 | return EINVAL; 279 | } 280 | 281 | target->joined_on = current->tid; 282 | current->state = WAITING; 283 | interrupt_enable(&timer); 284 | 285 | while(target->state != FINISHED); 286 | 287 | if(retval) { 288 | *retval = target->result; 289 | } 290 | 291 | dprintf("%-15s: Exited\n", "mthread_join"); 292 | return 0; 293 | } 294 | 295 | /** 296 | * @brief Terminate calling thread 297 | * @param[in] retval Return value of the thread 298 | * @return Does not return to the caller 299 | * @note Performing a return from the start funciton of any thread results in 300 | * an implicit call to mthread_exit() 301 | */ 302 | void mthread_exit(void *retval) { 303 | dprintf("%-15s: TID %d exiting\n", "mthread_exit", current->tid); 304 | interrupt_disable(&timer); 305 | 306 | current->state = FINISHED; 307 | current->result = retval; 308 | 309 | if(current->joined_on != -1) { 310 | mthread *target = search_on_tid(task_q, current->joined_on); 311 | target->state = READY; 312 | } 313 | 314 | interrupt_enable(&timer); 315 | mthread_yield(); 316 | } 317 | 318 | /** 319 | * @brief Yield the processor 320 | */ 321 | void mthread_yield(void) { 322 | dprintf("%-15s: Yielding to next thread\n", "mthread_yield"); 323 | raise(SIGVTALRM); 324 | } 325 | 326 | /** 327 | * @brief Send a signal to a thread 328 | * @param[in] thread Thread handle of thread to which signal needs to be sent 329 | * @param[in] sig Signal number corresponding to signal 330 | * @return On success, returns 0; on error, it returns an error number 331 | */ 332 | int mthread_kill(mthread_t thread, int sig) { 333 | dprintf("%-15s: Started\n", "mthread_kill"); 334 | if(sig < 0 || sig > NSIG) 335 | return EINVAL; 336 | 337 | if(thread == current->tid) { 338 | dprintf("%-15s: Raised signal %d for tid %d\n", "mthread_kill", sig, current->tid); 339 | return raise(sig); 340 | } 341 | 342 | interrupt_disable(&timer); 343 | mthread *target = search_on_tid(task_q, thread); 344 | if(target == NULL) { 345 | interrupt_enable(&timer); 346 | return EINVAL; 347 | } 348 | 349 | sigaddset(&target->sigpending, sig); 350 | 351 | dprintf("%-15s: Added signal %d to pending signals of TID %d\n", "mthread_kill", sig, target->tid); 352 | dprintf("%-15s: Exited\n", "mthread_kill"); 353 | interrupt_enable(&timer); 354 | return 0; 355 | } 356 | 357 | /** 358 | * @brief Detach a thread 359 | * @param[in] thread Thread handle of thread to be detached 360 | * @return On success, returns 0; on error, it returns an error number 361 | * @note Once a thread has been detached, it can't be joined with 362 | * mthread_join() or be made joinable again. 363 | */ 364 | int mthread_detach(mthread_t thread) { 365 | interrupt_disable(&timer); 366 | mthread *target = search_on_tid(task_q, thread); 367 | 368 | if(target == NULL) { 369 | interrupt_enable(&timer); 370 | return ESRCH; 371 | } 372 | 373 | if(target->joined_on != -1) { 374 | interrupt_enable(&timer); 375 | return EINVAL; 376 | } 377 | 378 | target->joinable = FALSE; 379 | dprintf("%-15s: Marked TID %d as detached\n", "mthread_detach", thread); 380 | 381 | interrupt_enable(&timer); 382 | return 0; 383 | } 384 | 385 | /** 386 | * @brief Compare Thread IDs 387 | * @param[in] t1 Thread handle of thread 1 388 | * @param[in] t2 Thread handle of thread 2 389 | * @return 0 on success, and non-zero on failure 390 | */ 391 | int mthread_equal(mthread_t t1, mthread_t t2) { 392 | return t1 - t2; 393 | } -------------------------------------------------------------------------------- /many-one/src/queue.c: -------------------------------------------------------------------------------- 1 | /** 2 | * @file queue.c 3 | * @brief Singly linked queue for thread control blocks 4 | * @author Mayank Jain 5 | * @bug No known bugs 6 | */ 7 | 8 | #include 9 | #include 10 | #include 11 | #include "queue.h" 12 | 13 | /** 14 | * @brief Initialise the queue 15 | * @param[in] q Pointer to queue 16 | */ 17 | void initialize(queue *q) { 18 | q->count = 0; 19 | q->head = NULL; 20 | q->tail = NULL; 21 | } 22 | 23 | /** 24 | * @brief Check if queue is empty 25 | * @param[in] q Pointer to queue 26 | * @return If empty, returns 1; else 0 27 | */ 28 | int isempty(queue *q) { 29 | if(q->head == NULL) { 30 | assert(q->count == 0); 31 | assert(q->tail == 0); 32 | } 33 | return (q->head == NULL); 34 | } 35 | 36 | /** 37 | * @brief Enqueue a TCB in the queue 38 | * @param[in] q Pointer to queue 39 | * @param[in] thd Pointer to TCB 40 | */ 41 | void enqueue(queue *q, mthread *thd) { 42 | node *tmp = calloc(1, sizeof(node)); 43 | tmp->thd = thd; 44 | tmp->next = NULL; 45 | 46 | if(isempty(q)) { 47 | q->head = q->tail = tmp; 48 | } 49 | else { 50 | q->tail->next = tmp; 51 | q->tail = tmp; 52 | } 53 | q->count++; 54 | 55 | return; 56 | } 57 | 58 | /** 59 | * @brief Dequeue a TCB in the queue 60 | * @param[in] q Pointer to queue 61 | * @return Pointer to TCB dequeued; Return NULL if empty 62 | */ 63 | mthread *dequeue(queue *q) { 64 | if(isempty(q)) 65 | return NULL; 66 | 67 | node *tmp = q->head; 68 | mthread *n = q->head->thd; 69 | 70 | q->head = q->head->next; 71 | q->count--; 72 | 73 | if(q->head == NULL) { 74 | q->tail = NULL; 75 | } 76 | 77 | free(tmp); 78 | return(n); 79 | } 80 | 81 | /** 82 | * @brief Get count of TCBs in queue 83 | * @param[in] q Pointer to queue 84 | * @return Count 85 | */ 86 | int getcount(queue *q) { 87 | return q->count; 88 | } 89 | 90 | /** 91 | * @brief Display TCBs in queue 92 | * @param[in] q Pointer to queue 93 | */ 94 | void display(queue *q) { 95 | if(isempty(q)) 96 | return; 97 | 98 | node *runner = q->head; 99 | printf("Queue (%d): ", q->count); 100 | while(runner) { 101 | printf("%d ", runner->thd->tid); 102 | runner = runner->next; 103 | } 104 | printf("\n"); 105 | } 106 | 107 | /** 108 | * @brief Search for a TCB based on TID in the queue 109 | * @param[in] q Pointer to queue 110 | * @param[in] tid TID of the target thread 111 | * @return Pointer to target thread; Return NULL if empty 112 | */ 113 | mthread *search_on_tid(queue *q, pid_t tid) { 114 | if(isempty(q)) 115 | return NULL; 116 | 117 | node *runner = q->head; 118 | while(runner) { 119 | if (runner->thd->tid == tid) { 120 | return runner->thd; 121 | } 122 | runner = runner->next; 123 | } 124 | return NULL; 125 | } 126 | 127 | /** 128 | * @brief Destroy the queue 129 | * @param[in] q Pointer to queue 130 | */ 131 | void destroy(queue *q) { 132 | if(isempty(q)) 133 | return; 134 | 135 | node *curr = q->head, *next; 136 | for(int i = 0; i < q->count; i++) { 137 | next = curr->next; 138 | free(curr->thd); 139 | free(curr); 140 | curr = next; 141 | } 142 | 143 | return; 144 | } -------------------------------------------------------------------------------- /many-one/src/spin_lock.c: -------------------------------------------------------------------------------- 1 | /** 2 | * @file spin_lock.c 3 | * @brief Spinlock synchronisation primitive 4 | * @author Mayank Jain 5 | * @bug No known bugs 6 | */ 7 | 8 | #include 9 | #include 10 | #include 11 | #include "mthread.h" 12 | 13 | /** 14 | * @brief Atomic Compare and Swap 15 | * @param[in,out] lock_addr Pointer to lock 16 | * @param[in] expected Expected value of lock 17 | * @param[in] desirec Desired value of lock 18 | * @return Upon success, the macro returns true. Upon failure, the desired 19 | * value is overwritten with the value of the atomic variable and false is 20 | * returned. 21 | */ 22 | static inline int atomic_cas(int *lock_addr, int expected, int desired) { 23 | return atomic_compare_exchange_strong(lock_addr, &expected, desired); 24 | } 25 | 26 | /** 27 | * @brief Initialise the spinlock 28 | * @param[out] lock Pointer to the spinlock 29 | * @note Reinitialization of a lock held by other threads may lead to 30 | * unexpected results, hence this function must be called only once 31 | * @return On success, returns 0; on error, it returns an error number 32 | */ 33 | int mthread_spin_init(mthread_spinlock_t *lock) { 34 | assert(lock); 35 | lock->value = UNLOCKED; 36 | return 0; 37 | } 38 | 39 | /** 40 | * @brief Lock a spinlock 41 | * @param[in,out] lock Pointer to the spinlock 42 | * @note The call is blocking and will return only if the lock is acquired 43 | * @return On success, returns 0; on error, it returns an error number 44 | */ 45 | int mthread_spin_lock(mthread_spinlock_t *lock) { 46 | assert(lock); 47 | while (!atomic_cas(&lock->value, UNLOCKED, LOCKED)); 48 | return 0; 49 | } 50 | 51 | /** 52 | * @brief Try locking a spinlock 53 | * @param[in,out] lock Pointer to the spinlock 54 | * @note The call returns immediately if acquiring lock fails 55 | * @return On success, returns 0; on error, it returns an error number 56 | */ 57 | int mthread_spin_trylock(mthread_spinlock_t *lock) { 58 | assert(lock); 59 | if(atomic_cas(&lock->value, UNLOCKED, LOCKED)) 60 | return 0; 61 | 62 | return EBUSY; 63 | } 64 | 65 | /** 66 | * @brief Unlock a spinlock 67 | * @param[in,out] lock Pointer to the spinlock 68 | * @note Calling mthread_spin_unlock() on a lock that is not held by the 69 | * caller results in undefined behavior. 70 | * @return On success, returns 0; on error, it returns an error number 71 | */ 72 | int mthread_spin_unlock(mthread_spinlock_t *lock) { 73 | assert(lock); 74 | atomic_cas(&lock->value, LOCKED, UNLOCKED); 75 | return 0; 76 | } -------------------------------------------------------------------------------- /many-one/src/stack.c: -------------------------------------------------------------------------------- 1 | /** 2 | * @file stack.c 3 | * @brief Thread stack allocation and deallocation functions 4 | * @author Mayank Jain 5 | * @bug No known bugs 6 | */ 7 | 8 | #include 9 | #include 10 | #include 11 | #include 12 | #include "stack.h" 13 | 14 | /** 15 | * @brief Get the stack size of a thread 16 | * @return Size in bytes 17 | */ 18 | size_t get_stack_size(void) { 19 | struct rlimit limit; 20 | getrlimit(RLIMIT_STACK, &limit); 21 | return limit.rlim_cur; 22 | } 23 | 24 | /** 25 | * @brief Get the page size of a thread 26 | * @return Size in bytes 27 | */ 28 | static size_t get_page_size(void) { 29 | return sysconf(_SC_PAGESIZE); 30 | } 31 | 32 | /** 33 | * @brief Allocate a stack 34 | * @param[in] stack_size Size of stack to mmap 35 | * @return Pointer to the base of the stack 36 | */ 37 | void * allocate_stack(size_t stack_size) { 38 | size_t page_size = get_page_size(); 39 | 40 | void *base = mmap(NULL, 41 | stack_size + page_size, 42 | PROT_READ | PROT_WRITE, 43 | MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, 44 | -1, 45 | 0); 46 | if(base == MAP_FAILED) 47 | return NULL; 48 | 49 | if(mprotect(base, page_size, PROT_NONE) == -1) { 50 | munmap(base, stack_size + page_size); 51 | return NULL; 52 | } 53 | 54 | return base + page_size; 55 | } 56 | 57 | /** 58 | * @brief Deallocate a stack 59 | * @param[in] base Base of the stack 60 | * @param[in] stack_size Size of stack to mmap 61 | * @return On success, returns 0; On error, returns -1 62 | */ 63 | int deallocate_stack(void *base, size_t stack_size) { 64 | size_t page_size = get_page_size(); 65 | return munmap(base - page_size, stack_size + page_size); 66 | } -------------------------------------------------------------------------------- /many-one/src/utils.c: -------------------------------------------------------------------------------- 1 | /** 2 | * @file utils.c 3 | * @brief Utility functions 4 | * @author Mayank Jain 5 | * @bug No known bugs 6 | */ 7 | 8 | #include "utils.h" 9 | 10 | /** 11 | * @brief Copy a string of length atmost n bytes including '\0' character 12 | * @param[in,out] dst String to be copied into 13 | * @param[in] src String to be copied from 14 | * @param[in] dst_size Number of characters to copy 15 | * @return Pointer to first character of destination string 16 | */ 17 | char *util_strncpy(char *dst, const char *src, size_t dst_size) { 18 | if(dst_size == 0) 19 | return dst; 20 | 21 | char *d = dst; 22 | char *end = dst + dst_size - 1; 23 | 24 | while(d < end) { 25 | if((*d = *src) == '\0') 26 | return dst; 27 | d++; 28 | src++; 29 | } 30 | *d = '\0'; 31 | 32 | return dst; 33 | } -------------------------------------------------------------------------------- /many-one/test/detach_state_test.c: -------------------------------------------------------------------------------- 1 | /** 2 | * Example of thread creation and termination 3 | * This is a example to illustrate how execution times are affected 4 | * by true parallelism versus interleaved execution. 5 | * The behavior depends on the first argument. 6 | * See function usage() for details. 7 | */ 8 | 9 | #define _XOPEN_SOURCE 500 10 | #define _REENTRANT 11 | #include "mthread.h" 12 | #include 13 | #include 14 | #include 15 | #include 16 | #include 17 | #include 18 | #include 19 | 20 | #define MCHECK(FCALL) \ 21 | { \ 22 | int result; \ 23 | if ((result = (FCALL)) != 0) { \ 24 | fprintf(stderr, "FATAL: %s (%s)", strerror(result), #FCALL); \ 25 | exit(-1); \ 26 | } \ 27 | } 28 | 29 | #define NTHREADS 5 30 | #define NITERATIONS 1000000 31 | 32 | int idx[NTHREADS]; 33 | clock_t start, end; 34 | 35 | void *func(void *arg) 36 | { 37 | int *idx = (int *)arg; 38 | fprintf(stderr, "Thread %d started\n", *idx); 39 | 40 | /** 41 | * The following is to keep the CPU busy for a fixed amount 42 | * of work, so we can compare how long it takes with several 43 | * threads versus a single thread 44 | */ 45 | for (long int k = 0; k < NITERATIONS; k++) { 46 | continue; 47 | } 48 | end = clock(); 49 | 50 | fprintf(stderr, "Thread %d exited\n", *idx); 51 | 52 | *idx = *idx * 10; 53 | return (void *)*idx; 54 | } 55 | 56 | void usage() 57 | { 58 | fprintf(stderr, "Usage: detach_state_test [ n | x | j | d ]\n" 59 | "n : JOINABLE threads, but don't wait\n" 60 | "j : JOINABLE threads, with mthread_join()\n" 61 | "d : DETACHED threads, and don't wait\n" 62 | "x : DETACHED threads, and wait 3 seconds\n"); 63 | } 64 | 65 | int main(int argc, char **argv) 66 | { 67 | int i; 68 | double elapsed_time = 0; 69 | mthread_attr_t attrs; 70 | mthread_t thread[NTHREADS]; 71 | void *value_ptr; 72 | 73 | if (argc != 2) { 74 | usage(); 75 | exit(-1); 76 | } 77 | printf("----------------------------------------------\n"); 78 | printf("Understanding Thread States \n"); 79 | printf("----------------------------------------------\n"); 80 | 81 | start = clock(); 82 | for (long int k = 0; k < NITERATIONS; k++) { 83 | continue; 84 | } 85 | end = clock(); 86 | 87 | /* Time elapsed in seconds */ 88 | elapsed_time = (end - start) / (double)CLOCKS_PER_SEC; 89 | fprintf(stderr, "Time taken for one loop = %f seconds\n", elapsed_time); 90 | 91 | mthread_init(); 92 | mthread_attr_init(&attrs); 93 | 94 | /** 95 | * Use the command-line argument to decide whether to create 96 | * the threads detached or joinable 97 | */ 98 | if ((strcmp(argv[1], "d") == 0) || (strcmp(argv[1], "x") == 0)) { 99 | MCHECK(mthread_attr_set(&attrs, MTHREAD_ATTR_JOINABLE, JOINABLE)); 100 | } 101 | 102 | /* Create threads */ 103 | for (i = 0; i < NTHREADS; i++) { 104 | idx[i] = i; 105 | MCHECK(mthread_create(&thread[i], &attrs, func, (void *)&idx[i])); 106 | fprintf(stderr, "Thread %d created\n", i); 107 | } 108 | 109 | 110 | /* Wait for the threads to complete */ 111 | if (strcmp(argv[1], "j") == 0) { 112 | for (i = 0; i < NTHREADS; i++) { 113 | MCHECK(mthread_join(thread[i], &value_ptr)); 114 | fprintf(stderr, "Thread %d returned value %d\n", i, (int)value_ptr); 115 | } 116 | } 117 | 118 | /* Find out how long the computation took */ 119 | end = clock(); 120 | 121 | if (strcmp(argv[1], "x") == 0) { 122 | fprintf(stderr, "Main thread waiting 3 seconds\n"); 123 | sleep(3); 124 | } 125 | 126 | elapsed_time = (end - start) / (double)CLOCKS_PER_SEC; 127 | 128 | fprintf(stderr, "Time taken by all %d threads = %f seconds\n", NTHREADS, elapsed_time); 129 | 130 | fprintf(stderr, "Main thread exiting\n"); 131 | 132 | printf("----------------------------------------------\n"); 133 | 134 | return 0; 135 | } 136 | -------------------------------------------------------------------------------- /many-one/test/matrix_test.c: -------------------------------------------------------------------------------- 1 | /** 2 | * Matrix multiplication using three threads using 3 | * data parralelism. 4 | * Input is STDIN 5 | * Input files are available in ../data 6 | * Namely 1.txt 2.txt 3.txt 7 | * Output is on STDOUT 8 | */ 9 | 10 | #include "mthread.h" 11 | #include 12 | #include 13 | #include 14 | #include 15 | #include 16 | 17 | #define MCHECK(FCALL) \ 18 | { \ 19 | int result; \ 20 | if ((result = (FCALL)) != 0) { \ 21 | fprintf(stderr, "FATAL: %s (%s)", strerror(result), #FCALL); \ 22 | exit(-1); \ 23 | } \ 24 | } 25 | 26 | /* Number of threads to use */ 27 | #define NUM_OF_THREADS 3 28 | 29 | /* Structure to define a matrix */ 30 | typedef struct { 31 | int **a; 32 | int rows; 33 | int cols; 34 | }matrix; 35 | 36 | /* Global matrices to allow easier threading */ 37 | matrix a, b, c; 38 | 39 | int running = 1; 40 | 41 | /** 42 | * Initialise the matrix 43 | * @param m pointer to matrix 44 | */ 45 | void initMatrix(matrix *m) { 46 | m->a = (int **)malloc(sizeof(int *) * m->rows); 47 | 48 | for(int i = 0; i < m->rows; i++) 49 | m->a[i] = (int *)malloc(sizeof(int) * m->cols); 50 | 51 | for(int i = 0; i < m->rows; i++) 52 | for(int j = 0; j < m->cols; j++) 53 | m->a[i][j] = 0; 54 | } 55 | 56 | /** 57 | * Build matrix from STDIN 58 | * Assume matrix is not initialised 59 | * @param m pointer to matrix 60 | */ 61 | void buildMatrix(matrix *m) { 62 | initMatrix(m); 63 | 64 | for(int i = 0; i < m->rows; i++) { 65 | for(int j = 0; j < m->cols; j++) { 66 | fscanf(stdin, "%d", &(m->a[i][j])); 67 | } 68 | } 69 | } 70 | 71 | /** 72 | * Print matrix on STDOUT 73 | * @param m matrix to be printed 74 | */ 75 | void printMatrix(matrix m) { 76 | for(int i = 0; i < m.rows; i++) { 77 | for(int j = 0; j < m.cols; j++) { 78 | fprintf(stdout, "%d ", m.a[i][j]); 79 | } 80 | fprintf(stdout, "\n"); 81 | } 82 | } 83 | 84 | /** 85 | * Frees memory allocated 86 | * @param m pointer to matrix 87 | */ 88 | void freeMatrix(matrix *m) { 89 | for(int i = 0; i < m->rows; i++) { 90 | free(m->a[i]); 91 | } 92 | free(m->a); 93 | } 94 | 95 | /** 96 | * Multiply two matrices 97 | * @param arg an integer array having details about the thread's rows of interest 98 | */ 99 | void * multiplyMatrix(void *arg) { 100 | int i, j, k, sum; 101 | int *t = (int *)arg; 102 | int rowStart = t[0]; 103 | int rowEnd = t[1]; 104 | 105 | // printf("Thread %d:\trowStart %d\trowEnd %d\tcols %d\n", t[3], rowStart, rowEnd, cols); 106 | 107 | for(i = rowStart; i < rowEnd; i++) { 108 | for(j = 0; j < c.cols; j++) { 109 | sum = 0; 110 | for(k = 0; k < a.cols; k++) { 111 | sum += a.a[i][k] * b.a[k][j]; 112 | } 113 | c.a[i][j] = sum; 114 | } 115 | } 116 | 117 | mthread_exit(NULL); 118 | } 119 | 120 | int main() { 121 | int i, d[NUM_OF_THREADS][2]; 122 | 123 | /* Initialise first matrix */ 124 | fscanf(stdin, "%d %d", &(a.rows), &(a.cols)); 125 | buildMatrix(&a); 126 | 127 | /* Initialise second matrix */ 128 | fscanf(stdin, "%d %d", &(b.rows), &(b.cols)); 129 | buildMatrix(&b); 130 | 131 | /* Set result matrix rows and cols */ 132 | c.rows = a.rows; 133 | c.cols = b.cols; 134 | 135 | /* Initialise the result matrix */ 136 | initMatrix(&c); 137 | 138 | /* Thread identifiers */ 139 | mthread_t tid[NUM_OF_THREADS]; 140 | 141 | MCHECK(mthread_init()); 142 | 143 | for (i = 0; i < NUM_OF_THREADS; i++) { 144 | /* Calculate starting row thread should start process */ 145 | d[i][0] = ceil(i * (double)(c.rows)/NUM_OF_THREADS); 146 | 147 | /* Calculate ending row thread should start process */ 148 | d[i][1] = ceil((i + 1) * (double)(c.rows)/NUM_OF_THREADS); 149 | 150 | /* Create thread and pass args */ 151 | MCHECK(mthread_create(&tid[i], NULL, multiplyMatrix, d[i])); 152 | } 153 | 154 | /* Wait until all threads complete */ 155 | for(i = 0; i < NUM_OF_THREADS; i++) { 156 | MCHECK(mthread_join(tid[i], NULL)); 157 | } 158 | 159 | printMatrix(c); 160 | 161 | /* Free all allocated memory */ 162 | freeMatrix(&a); 163 | freeMatrix(&b); 164 | freeMatrix(&c); 165 | return 0; 166 | } -------------------------------------------------------------------------------- /many-one/test/robust_test.c: -------------------------------------------------------------------------------- 1 | /** 2 | * Unit testing for public API functions provided by the library 3 | */ 4 | 5 | #define _REENTRANT 6 | #include "mthread.h" 7 | #include 8 | #include 9 | #include 10 | #include 11 | #include 12 | 13 | #define NTHREADS 5 14 | 15 | #define print(str) write(STDOUT_FILENO, str, strlen(str)) 16 | 17 | #define MCHECKPASS(FCALL) \ 18 | { \ 19 | int result; \ 20 | if ((result = (FCALL)) != 0) \ 21 | { \ 22 | fprintf(stderr, "FATAL: %s (%s)\n", strerror(result), #FCALL); \ 23 | fprintf(stdout, "TEST FAILED\n\n"); \ 24 | exit(EXIT_FAILURE); \ 25 | } \ 26 | else \ 27 | { \ 28 | fprintf(stdout, "TEST PASSED\n\n"); \ 29 | } \ 30 | } 31 | 32 | #define MCHECKFAIL(FCALL) \ 33 | { \ 34 | int result; \ 35 | if ((result = (FCALL)) != 0) \ 36 | { \ 37 | fprintf(stderr, "FATAL: %s (%s)\n", strerror(result), #FCALL); \ 38 | fprintf(stdout, "TEST PASSED\n\n"); \ 39 | } \ 40 | else \ 41 | { \ 42 | fprintf(stdout, "TEST FAILED\n\n"); \ 43 | exit(EXIT_FAILURE); \ 44 | } \ 45 | } 46 | 47 | #define MCHECK(FCALL) \ 48 | { \ 49 | int result; \ 50 | if ((result = (FCALL)) != 0) \ 51 | { \ 52 | fprintf(stderr, "FATAL: %s (%s)\n", strerror(result), #FCALL); \ 53 | } \ 54 | } 55 | 56 | int running, count; 57 | 58 | void handler(int sig) { 59 | print("Inside the handler\n"); 60 | running = 0; 61 | } 62 | 63 | void *thread1(void *arg) { 64 | printf("In thread 1\n"); 65 | mthread_exit((void *)64); 66 | } 67 | 68 | void *thread2(void *arg) { 69 | printf("In thread 2\n"); 70 | return (void *)2; 71 | } 72 | 73 | void *infinite(void *arg) { 74 | printf("In thread having infinite while loop\n"); 75 | while(running); 76 | return (void *)128; 77 | } 78 | void* threadone(void *args) { 79 | count++; 80 | } 81 | 82 | void* threadtwo(void *args) { 83 | mthread_t tid; 84 | mthread_create(&tid, NULL, threadone, NULL); 85 | mthread_join(tid, NULL); 86 | count++; 87 | } 88 | 89 | void* threadthree(void *args) { 90 | return (void *)1; 91 | } 92 | 93 | void* keep_going(void *args) { 94 | for (long long int i = 0; i < 10000000; i++); 95 | } 96 | 97 | 98 | int main(int argc, char **argv) { 99 | mthread_init(); 100 | 101 | printf("-------------------------------------------\n"); 102 | printf("Thread Attribute Handling\n"); 103 | printf("-------------------------------------------\n"); 104 | printf("1] Handling detach state of a thread\n"); 105 | { 106 | int join; 107 | mthread_attr_t *attr = mthread_attr_new(); 108 | MCHECK(mthread_attr_get(attr, MTHREAD_ATTR_JOINABLE, &join)); 109 | printf("Detach State: Expected 1 Actual %d\n", join); 110 | MCHECK(mthread_attr_set(attr, MTHREAD_ATTR_JOINABLE, DETACHED)); 111 | MCHECK(mthread_attr_get(attr, MTHREAD_ATTR_JOINABLE, &join)); 112 | printf("Detach State: Expected 0 Actual %d\n", join); 113 | MCHECK(mthread_attr_destroy(attr)); 114 | printf("TEST PASSED\n\n"); 115 | } 116 | 117 | printf("2] Handling stack of a thread\n"); 118 | { 119 | size_t s; 120 | void *t; 121 | void *stack = malloc(10 * 1024); 122 | mthread_attr_t *attr = mthread_attr_new(); 123 | MCHECK(mthread_attr_get(attr, MTHREAD_ATTR_STACK_SIZE, &s)); 124 | MCHECK(mthread_attr_get(attr, MTHREAD_ATTR_STACK_ADDR, &t)); 125 | printf("Default stack size = %lu\n", s); 126 | printf("Default stack address = %p\n", t); 127 | 128 | MCHECK(mthread_attr_set(attr, MTHREAD_ATTR_STACK_SIZE, 10 * 1024)); 129 | MCHECK(mthread_attr_set(attr, MTHREAD_ATTR_STACK_ADDR, stack)); 130 | printf("Set stack size = 10240\n"); 131 | printf("Set stack address = %p\n", stack); 132 | 133 | MCHECK(mthread_attr_get(attr, MTHREAD_ATTR_STACK_SIZE, &s)); 134 | MCHECK(mthread_attr_get(attr, MTHREAD_ATTR_STACK_ADDR, &t)); 135 | printf("New stack size = %lu\n", s); 136 | printf("New stack address = %p\n", t); 137 | 138 | MCHECK(mthread_attr_destroy(attr)); 139 | if(s == 10240 && t == stack) { 140 | printf("TEST PASSED\n\n"); 141 | } 142 | else { 143 | printf("TEST FAILED\n\n"); 144 | exit(EXIT_FAILURE); 145 | } 146 | } 147 | 148 | printf("-------------------------------------------\n"); 149 | printf("Thread Create\n"); 150 | printf("-------------------------------------------\n"); 151 | printf("1] Start Routine is NULL\n"); 152 | { 153 | mthread_t tid; 154 | MCHECKFAIL(mthread_create(&tid, NULL, NULL, NULL)); 155 | } 156 | 157 | printf("2] Create Thread with Default Attributes\n"); 158 | { 159 | mthread_t tid; 160 | MCHECK(mthread_create(&tid, NULL, thread1, NULL)); 161 | MCHECK(mthread_join(tid, NULL)); 162 | fprintf(stdout, "TEST PASSED\n\n"); 163 | } 164 | 165 | printf("3] Create Detached Thread\n"); 166 | { 167 | mthread_t tid; 168 | mthread_attr_t attr; 169 | mthread_attr_init(&attr); 170 | mthread_attr_set(&attr, MTHREAD_ATTR_JOINABLE, DETACHED); 171 | MCHECK(mthread_create(&tid, &attr, thread1, NULL)); 172 | MCHECKFAIL(mthread_join(tid, NULL)); 173 | } 174 | 175 | printf("4] Create Thread having Stack Size of 10KB\n"); 176 | { 177 | mthread_t tid; 178 | mthread_attr_t attr; 179 | mthread_attr_init(&attr); 180 | mthread_attr_set(&attr, MTHREAD_ATTR_STACK_SIZE, 10 * 1024); 181 | void *stack = malloc(10 * 1024); 182 | mthread_attr_set(&attr, MTHREAD_ATTR_STACK_ADDR, stack); 183 | MCHECK(mthread_create(&tid, &attr, thread1, NULL)); 184 | MCHECK(mthread_join(tid, NULL)); 185 | fprintf(stdout, "TEST PASSED\n\n"); 186 | } 187 | 188 | printf("-------------------------------------------\n"); 189 | printf("Thread Join\n"); 190 | printf("-------------------------------------------\n"); 191 | printf("1] Invalid Thread Handle Passed\n"); 192 | { 193 | mthread_t tid; 194 | MCHECK(mthread_create(&tid, NULL, thread1, NULL)); 195 | MCHECKFAIL(mthread_join(1000, NULL)); 196 | } 197 | 198 | printf("2] Joining on a detached thread\n"); 199 | { 200 | mthread_t tid; 201 | mthread_attr_t attr; 202 | mthread_attr_init(&attr); 203 | mthread_attr_set(&attr, MTHREAD_ATTR_JOINABLE, DETACHED); 204 | MCHECK(mthread_create(&tid, &attr, thread1, NULL)); 205 | MCHECKFAIL(mthread_join(tid, NULL)); 206 | } 207 | 208 | printf("3] Joining on an already joined thread\n"); 209 | { 210 | mthread_t tid; 211 | MCHECK(mthread_create(&tid, NULL, thread1, NULL)); 212 | MCHECK(mthread_join(tid, NULL)); 213 | MCHECKFAIL(mthread_join(tid, NULL)); 214 | } 215 | 216 | printf("4] Joining on a thread and collecting exit status\n"); 217 | { 218 | void *value; 219 | mthread_t tid; 220 | MCHECK(mthread_create(&tid, NULL, thread1, NULL)); 221 | MCHECK(mthread_join(tid, &value)); 222 | fprintf(stdout, "Expected Exit Status is %d\n", 64); 223 | fprintf(stdout, "Actual Exit Status is %d\n", (int) value); 224 | if((int)value == 64) { 225 | fprintf(stdout, "TEST PASSED\n\n"); 226 | } 227 | else { 228 | fprintf(stdout, "TEST FAILED\n\n"); 229 | exit(EXIT_FAILURE); 230 | } 231 | } 232 | 233 | printf("5] Joining on more than one thread\n"); 234 | { 235 | mthread_t tid[5]; 236 | for(int i = 0; i < 5; i++) { 237 | MCHECK(mthread_create(&tid[i], NULL, thread1, NULL)); 238 | fprintf(stdout, "Thread %d created\n", i); 239 | } 240 | for(int i = 0; i < 5; i++) { 241 | MCHECK(mthread_join(tid[i], NULL)); 242 | fprintf(stdout, "Thread %d joined\n", i); 243 | } 244 | fprintf(stdout, "TEST PASSED\n\n"); 245 | } 246 | 247 | printf("-------------------------------------------\n"); 248 | printf("Thread Kill\n"); 249 | printf("-------------------------------------------\n"); 250 | printf("1] Send invalid signal\n"); 251 | { 252 | mthread_t tid; 253 | signal(SIGUSR1, handler); 254 | running = 1; 255 | MCHECK(mthread_create(&tid, NULL, infinite, NULL)); 256 | MCHECK(mthread_kill(tid, -1)); 257 | running = 0; 258 | MCHECK(mthread_join(tid, NULL)); 259 | fprintf(stdout, "TEST PASSED\n\n"); 260 | } 261 | 262 | printf("2] Send signal to a thread\n"); 263 | { 264 | void *value; 265 | mthread_t tid; 266 | signal(SIGUSR1, handler); 267 | running = 1; 268 | MCHECK(mthread_create(&tid, NULL, infinite, NULL)); 269 | MCHECK(mthread_kill(tid, SIGUSR1)); 270 | MCHECK(mthread_join(tid, &value)); 271 | if((int)value == 128) { 272 | fprintf(stdout, "TEST PASSED\n\n"); 273 | } 274 | else { 275 | fprintf(stdout, "TEST FAILED\n\n"); 276 | exit(EXIT_FAILURE); 277 | } 278 | } 279 | 280 | printf("-------------------------------------------\n"); 281 | printf("Thread Exit\n"); 282 | printf("-------------------------------------------\n"); 283 | printf("1] Created Thread Uses Return To Exit\n"); 284 | { 285 | void *value; 286 | mthread_t tid; 287 | 288 | MCHECK(mthread_create(&tid, NULL, thread1, NULL)); 289 | MCHECK(mthread_join(tid, &value)); 290 | fprintf(stdout, "Expected Exit Status is %d\n", 64); 291 | fprintf(stdout, "Actual Exit Status is %d\n", (int) value); 292 | if((int)value == 64) { 293 | fprintf(stdout, "TEST PASSED\n\n"); 294 | } 295 | else { 296 | fprintf(stdout, "TEST FAILED\n\n"); 297 | exit(EXIT_FAILURE); 298 | } 299 | 300 | } 301 | printf("2] Created Thread Uses mthread_exit()\n"); 302 | { 303 | void *value; 304 | mthread_t tid; 305 | 306 | MCHECK(mthread_create(&tid, NULL, thread2, NULL)); 307 | MCHECK(mthread_join(tid, &value)); 308 | fprintf(stdout, "Expected Exit Status is %d\n", 2); 309 | fprintf(stdout, "Actual Exit Status is %d\n", (int) value); 310 | if((int)value == 2) { 311 | fprintf(stdout, "TEST PASSED\n\n"); 312 | } 313 | else { 314 | fprintf(stdout, "TEST FAILED\n\n"); 315 | exit(EXIT_FAILURE); 316 | } 317 | } 318 | 319 | printf("-------------------------------------------\n"); 320 | printf("Miscellaneous\n"); 321 | printf("-------------------------------------------\n"); 322 | 323 | printf("1] Create thread inside another thread\n"); 324 | { 325 | count = 0; 326 | mthread_t tid; 327 | MCHECK(mthread_create(&tid, NULL, threadtwo, NULL)); 328 | MCHECK(mthread_join(tid, NULL)); 329 | if (count == 2) { 330 | printf("TEST PASSED\n\n"); 331 | } 332 | else { 333 | printf("TEST FAILED\n\n"); 334 | exit(EXIT_FAILURE); 335 | } 336 | } 337 | printf("2] Scheduling between three threads\n"); 338 | { 339 | mthread_t tid[3]; 340 | for(int i = 0; i < 3; i++) { 341 | MCHECK(mthread_create(&tid[i], NULL, keep_going, NULL)); 342 | } 343 | for(int i = 0; i < 3; i++) { 344 | MCHECK(mthread_join(tid[i], NULL)); 345 | } 346 | printf("TEST PASSED\n\n"); 347 | } 348 | 349 | return 0; 350 | } -------------------------------------------------------------------------------- /many-one/test/spin_test.c: -------------------------------------------------------------------------------- 1 | /** 2 | * Example code for using spinlocks. This program creates 5 threads 3 | * each of which tries to increment two variables - one shared and one 4 | * individual. To access the shared variable spinlocks are used to guarantee 5 | * mutual exclusion and race conditions. Absence of race conditions are checked 6 | * by checking if the sum of inidividual values is same as that of the shared 7 | * variable. 8 | */ 9 | 10 | #define _GNU_SOURCE 11 | #include "mthread.h" 12 | #include 13 | #include 14 | #include 15 | #include 16 | 17 | #define MCHECK(FCALL) \ 18 | { \ 19 | int result; \ 20 | if ((result = (FCALL)) != 0) { \ 21 | fprintf(stderr, "FATAL: %s (%s)", strerror(result), #FCALL); \ 22 | exit(-1); \ 23 | } \ 24 | } 25 | 26 | 27 | #define print(str) write(1, str, strlen(str)) 28 | 29 | long long c = 0, c1 = 0, c2 = 0, c3 = 0, c4 = 0, c5 = 0, running = 1; 30 | 31 | mthread_spinlock_t lock; 32 | 33 | void *thread1(void *arg) { 34 | while(running == 1) { 35 | mthread_spin_lock(&lock); 36 | c++; 37 | mthread_spin_unlock(&lock); 38 | c1++; 39 | } 40 | } 41 | 42 | void *thread2(void *arg) { 43 | while(running == 1) { 44 | mthread_spin_lock(&lock); 45 | c++; 46 | mthread_spin_unlock(&lock); 47 | c2++; 48 | } 49 | } 50 | 51 | void *thread3(void *arg) { 52 | while(running == 1) { 53 | mthread_spin_lock(&lock); 54 | c++; 55 | mthread_spin_unlock(&lock); 56 | c3++; 57 | } 58 | } 59 | 60 | void *thread4(void *arg) { 61 | while(running == 1) { 62 | mthread_spin_lock(&lock); 63 | c++; 64 | mthread_spin_unlock(&lock); 65 | c4++; 66 | } 67 | } 68 | 69 | void *thread5(void *arg) { 70 | while(running == 1) { 71 | mthread_spin_lock(&lock); 72 | c++; 73 | mthread_spin_unlock(&lock); 74 | c5++; 75 | } 76 | } 77 | 78 | int main(int argc, char **argv) { 79 | mthread_t th1, th2, th3, th4, th5; 80 | 81 | fprintf(stdout, "----------------------------------\n"); 82 | fprintf(stdout, "Thread Spinlocks\n"); 83 | 84 | mthread_init(); 85 | mthread_spin_init(&lock); 86 | 87 | MCHECK(mthread_create(&th1, NULL, thread1, NULL)); 88 | MCHECK(mthread_create(&th2, NULL, thread2, NULL)); 89 | MCHECK(mthread_create(&th3, NULL, thread3, NULL)); 90 | MCHECK(mthread_create(&th4, NULL, thread4, NULL)); 91 | MCHECK(mthread_create(&th5, NULL, thread5, NULL)); 92 | fprintf(stdout, "Created 5 threads\n"); 93 | fprintf(stdout, "Letting threads run\n"); 94 | 95 | for(long long int i = 0; i < 1000000000; i++); 96 | 97 | running = 0; 98 | 99 | MCHECK(mthread_join(th1, NULL)); 100 | MCHECK(mthread_join(th2, NULL)); 101 | MCHECK(mthread_join(th3, NULL)); 102 | MCHECK(mthread_join(th4, NULL)); 103 | MCHECK(mthread_join(th5, NULL)); 104 | fprintf(stdout, "Joined on all 5 threads\n"); 105 | 106 | fprintf(stdout, "Thread 1 = %lld\n", c1); 107 | fprintf(stdout, "Thread 2 = %lld\n", c2); 108 | fprintf(stdout, "Thread 3 = %lld\n", c3); 109 | fprintf(stdout, "Thread 4 = %lld\n", c4); 110 | fprintf(stdout, "Thread 5 = %lld\n", c5); 111 | fprintf(stdout, "t1 + t2 + t3 + t4 + t5 = %lld\n", c1+c2+c3+c4+c5); 112 | fprintf(stdout, "Shared Variable = %lld\n", c); 113 | if(c1+c2+c3+c4+c5 == c) { 114 | fprintf(stdout, "TEST PASSED\n"); 115 | } 116 | else{ 117 | fprintf(stdout, "Test failed\n"); 118 | } 119 | fflush(stdout); 120 | fprintf(stdout, "----------------------------------\n"); 121 | 122 | return 0; 123 | } -------------------------------------------------------------------------------- /many-one/valgrind.sh: -------------------------------------------------------------------------------- 1 | #!/bin/zsh 2 | 3 | if [ $# -eq 0 ]; then 4 | echo "Usage ./valgrind.sh " 5 | else 6 | valgrind --leak-check=full \ 7 | --track-origins=yes \ 8 | --show-leak-kinds=all \ 9 | --verbose \ 10 | --log-file=valgrind-out.txt \ 11 | ./bin/$1 "${@:2}" 12 | fi 13 | 14 | # --leak-check=full : each individual leak will be shown in detail 15 | # --track-origins=yes : tracks the origins of uninitialized values, 16 | # which could be very useful for memory errors 17 | # --show-leak-kinds=all: show all of "definite, indirect, possible, 18 | # reachable" leak kinds in the "full" report 19 | # --verbose : tells you about unusual behavior of your program 20 | # --log-file : write to a file -------------------------------------------------------------------------------- /one-one/Makefile: -------------------------------------------------------------------------------- 1 | SRC_DIR := src 2 | OBJ_DIR := obj 3 | TEST_DIR := test 4 | BIN_DIR := bin 5 | DOC_DIR := docs 6 | 7 | SRC := $(wildcard $(SRC_DIR)/*.c) 8 | # $(info SRC is $(SRC)) 9 | 10 | OBJ := $(SRC:$(SRC_DIR)/%.c=$(OBJ_DIR)/%.o) 11 | # $(info OBJ is $(OBJ)) 12 | 13 | TEST_SRC := $(wildcard $(TEST_DIR)/*.c) 14 | # $(info TEST_SRC is $(TEST_SRC)) 15 | 16 | TEST_OBJ := $(TEST_SRC:$(TEST_DIR)/%.c=$(TEST_DIR)/%.o) 17 | # $(info TEST_OBJ is $(TEST_OBJ)) 18 | 19 | EXE := $(addprefix $(BIN_DIR)/, $(notdir $(basename $(TEST_SRC)))) 20 | # $(info EXE is $(EXE)) 21 | 22 | CPPFLAGS := -I include 23 | CFLAGS := -g -Wall -fpic 24 | # -g : For debugging purposes 25 | # -Wall : Print all warnings 26 | # -fpic : Use Position Independent Code. It means that the generated machine code is not dependent on being located at a specific address in order to work Ex. Jumps would be generated as relative rather than absolute 27 | TESTCFLAGS := -Wno-int-to-pointer-cast -Wno-pointer-to-int-cast -Wno-return-type 28 | LIB := libmthread.a 29 | LIBSO := libmthread.so 30 | LDFLAGS := -L. 31 | # LDLIBS := -lm 32 | 33 | CC := gcc 34 | AR := /usr/bin/ar 35 | RANLIB := /usr/bin/ranlib 36 | .PHONY: all clean lib exe docs 37 | 38 | DEBUG := 1 39 | ifeq ($(DEBUG),1) 40 | CFLAGS += -DDEBUG 41 | endif 42 | 43 | all: $(LIBSO) $(LIB) $(EXE) $(LIBSO) 44 | 45 | $(LIBSO) : $(OBJ) 46 | $(CC) -shared $(OBJ) -o $@ 47 | 48 | $(LIB) : $(OBJ) 49 | $(AR) rcs $(LIB) $(OBJ) 50 | $(RANLIB) $(LIB) 51 | 52 | $(OBJ_DIR)/%.o: $(SRC_DIR)/%.c | $(OBJ_DIR) 53 | $(CC) $(CPPFLAGS) $(CFLAGS) -c $< -o $@ 54 | 55 | $(BIN_DIR)/%: $(TEST_DIR)/%.o $(LIB) 56 | $(CC) $(LDFLAGS) $^ $(LDLIBS) -o $@ 57 | 58 | $(TEST_DIR)/%.o: $(TEST_DIR)/%.c | $(OBJ_DIR) 59 | $(CC) $(CPPFLAGS) $(CFLAGS) $(TESTCFLAGS) -c $< -o $@ 60 | 61 | $(OBJ_DIR): 62 | mkdir $@ 63 | 64 | docs: 65 | doxygen $(DOC_DIR)/doxy-config 66 | 67 | clean: 68 | $(RM) -rf $(OBJ) $(TEST_OBJ) $(LIB) $(EXE) $(LIBSO) $(DOC_DIR)/html $(DOC_DIR)/latex -------------------------------------------------------------------------------- /one-one/README.md: -------------------------------------------------------------------------------- 1 | # One-One Threading Model 2 | 3 | ![One to One Threading Model](./docs/one-to-one.png) 4 | 5 | ## Thread Library Initialisation 6 | 7 | + `mthread_init()` initializes the mthread library. It has to be the first mthread API function call in an application, and is mandatory. It's usually done at the begin of the `main()` function of the application. This implicitly initialises the data structures and transforms the single execution unit of the current process into a thread (the 'main' thread). It returns 0 on success. 8 | 9 | ## Thread Creation 10 | 11 | + On Linux, threads and processes are treated the same. They are both considered to be tasks. One process may consists of many threads. 12 | 13 | + Every thread has it's own TID (Thread ID), saved registers, stack pointer, instruction pointer, stack(local variables, return addresses, etc.), signal mask, and priority (scheduling information) and shares everything else with the parent process depending on flags used while cloning. 14 | + Scheduling is managed by the kernel scheduler itself. So no priority is maintained. 15 | + We need to maintain a separate stack and it's size per thread. 16 | 17 | + On Linux, kernel threads are created with the `clone` system call. It is similar to fork (creates a task which is executing the current program), however it differs in that clone specifies which resources should be shared. To create a thread, we call clone to create a task which shares as much as possible: The memory space, file descriptors and signal handlers, etc. 18 | 19 | + We allocate the memory that is to be used for the thread's stack using `mmap(2)` rather than `malloc(3)` because `mmap(2)` allocates a block of memory that starts on a page boundary and is a multiple of the page size. This is useful since we want to establish a guard page (a page with protection PROT_NONE) at the end of the stack using `mprotect(2)`. 20 | 21 | + The stack pointer passed to clone must reference the top of the stack, since on most processors the stack grows down. This is done by adding the size of the region to the base of the mmap'ed region. To avoid a memory leak, the stack must be freed once the thread has exited. 22 | 23 | + For book-keeping, thread specific data is maintained in a Thread Control Block (TCB). On creation of the every thread using `mthread_create()`, a TCB is allocated and initialized accordingly. 24 | 25 | + The new thread terminates in one of the following ways: 26 | + It calls `mthread_exit()`, specifying an exit status value that is available to another thread in the same process that calls `mthread_join()`. 27 | + It returns from `start_routine()`. This is equivalent to calling mthread_exit() with the value supplied in the return statement. 28 | + Any of the threads in the process calls `exit(3)`, or the main thread performs a return from main(). This causes the termination of all threads in the process. 29 | 30 | + To replicate above behaviour, the user's `start_function(args)` are wrapped in an internal `mthread_start()` function. 31 | 32 | + To change attributes of a thread like the stack size, stack base, name for user level debugging and it's detach state, an attribute object of threads is passed as the second argument to `mthread_create()`. The user allocates it, and then calls `mthread_attr_init` to intialize it and `mthread_attr_destroy` to clean it up. For more info, refer thread attribute handling. 33 | 34 | + On succesful thread creation, the thread library provides a **thread handle** as a return value which can be further used in different thread control functions. 35 | 36 | ## Thread Attribute Handling 37 | 38 | Attribute objects are used in mthread to store attributes for to be spawned threads. They are stand-alone/unbound attribute objects i.e. they cannot modify attributes of existing threads. The following attribute fields exists in attribute objects: 39 | 40 | + MTHREAD_ATTR_NAME (read-write) \[char *\] 41 | Name of thread (up to 64 characters are stored only), mainly for debugging purposes. 42 | 43 | + MTHREAD_ATTR_JOINABLE (read-write) \[int\] 44 | The thread detachment type, JOINABLE indicates a joinable thread, DETACHED indicates a detached thread. 45 | 46 | + MTHREAD_ATTR_STACK_SIZE (read-write) \[unsigned int\] 47 | The thread stack size in bytes. Use lower values with great care! 48 | 49 | + MTHREAD_ATTR_STACK_ADDR (read-write) \[char *\] 50 | A pointer to the lower address of a chunk of malloc(3)'ed memory for the stack. 51 | 52 | `mthread_attr_t mthread_attr_new(void);` 53 | This returns a new unbound attribute object. An implicit mthread_attr_init() is done on it. Any queries on this object just fetch stored attributes from it. And attribute modifications just change the stored attributes. Use such attribute objects to pre-configure attributes for to be spawned threads. 54 | 55 | `int mthread_attr_init(mthread_attr_t attr);` 56 | This initializes an attribute object attr to the default values: 57 | MTHREAD_ATTR_NAME := 'Unknown', 58 | MTHREAD_ATTR_JOINABLE := JOINABLE, 59 | MTHREAD_ATTR_STACK_SIZE := DEFAULT, 60 | MTHREAD_ATTR_STACK_ADDR := NULL. 61 | 62 | `int mthread_attr_set(mthread_attr_t attr, int field, ...);` 63 | This sets the attribute field in attr to a value specified as an additional argument on the variable argument list. The following attribute fields and argument pairs can be used: 64 | 65 | | Attribute | Type | 66 | |---------------------------|---------------| 67 | | MTHREAD_ATTR_NAME | char * | 68 | | MTHREAD_ATTR_JOINABLE | int | 69 | | MTHREAD_ATTR_STACK_SIZE | unsigned int | 70 | | MTHREAD_ATTR_STACK_ADDR | void * | 71 | 72 | `int mthread_attr_get(mthread_attr_t attr, int field, ...);` 73 | This retrieves the attribute field in attr and stores its value in the variable specified through a pointer in an additional argument on the variable argument list. The following fields and argument pairs can be used: 74 | 75 | | Attribute | Type | 76 | |---------------------------|---------------| 77 | | MTHREAD_ATTR_NAME | char ** | 78 | | MTHREAD_ATTR_JOINABLE | int * | 79 | | MTHREAD_ATTR_STACK_SIZE | unsigned int *| 80 | | MTHREAD_ATTR_STACK_ADDR | void ** | 81 | 82 | `int mthread_attr_destroy(mthread_attr_t attr);` 83 | This destroys a attribute object attr. After this attr is no longer a valid attribute object. 84 | 85 | ## Thread Joining 86 | 87 | + The `mthread_join()` function waits for the thread specified by thread to terminate. If that thread has already terminated, then `mthread_join()` returns immediately. The thread specified by thread must be joinable. 88 | 89 | + A thread may have to wait for the completion of another thread. If the caller thread waits for an incomplete target thread to join, then it will halt till the target thread exits. This wait is implemented using `futex(2)`. 90 | 91 | + When the thread was created, a variable of the TCB was set to it's TID. By passing CLONE_CHILD_CLEARTID to `clone(2)`, it is made sure that this variable has the TID as long as the thread is running. It also clears (zero) the TID at the location pointed by the variable when the child exits, and does a wakeup on the futex at that address. 92 | 93 | + Even if a thread has finished execution, none of its allocated resources are freed. The resources of the thread are released only after the program exits to improve time complexity. 94 | 95 | + A thread must be joined on only once. Any further joins on an already joined thread will return errors. 96 | 97 | + All of the threads in a process are peers: any thread can join with any other thread in the process. 98 | 99 | ## Thread Signals 100 | 101 | + Signals may be sent to a specific thread or a thread group using `mthread_kill()`. 102 | 103 | + For this `tgkill(2)` was used to direct the signals to the target thread. 104 | 105 | + Note : Signal dispositions and actions are process-wide: if an unhandled signal is delivered to a thread, then it will affect (terminate, stop, continue, be ignored in) all members of the thread group. 106 | 107 | ## Thread Exiting 108 | 109 | + As mentioned previously, a thread can exit using the `mthread_exit()` function. The thread can also return a value while it is exiting, to be returned to the thread joining on it. This is done by storing it's result in the TCB. 110 | 111 | + When the thread was created, `clone(2)` was passed the `mthread_start()` as start function of the thread. To exit safely, it is important that `mthread_exit()` returns to `mthread_start()` since that is how clone will return. For this `sigsetjmp(3)` and `siglongjmp(3)` are used. 112 | 113 | ## Thread Yielding 114 | 115 | + Yield execution control to next thread by simply calling `mthread_yield()`. It is simply a wrapper for a `sched_yield(2)` 116 | 117 | ## Thread Detachment 118 | 119 | + The `mthread_detach()` function marks the thread passed as argument as detached. Any other thread trying to join on a detached thread will result in an error. 120 | 121 | ## Thread Equality 122 | 123 | + The `mthread_equal()` function checks whether the threads identified by their thread handles are the same or not. Returns 0 if equal and non-zero if not. 124 | 125 | ## Synchronisation Primitives 126 | 127 | ### Spinlocks 128 | 129 | A spinlock is a lock which causes a thread trying to acquire it to simply wait in a loop ("spin") while repeatedly checking if the lock is available. The advantage of a spinlock is that the thread is kept active and does not enter a sleep-wait for a mutex to become available, thus can perform better in certain cases than typical blocking-sleep-wait style mutexes. 130 | 131 | Functions used in conjunction with the spinlock: 132 | 133 | Creating/Destroying: 134 | `mthread_spinlock_init()` 135 | `mthread_spinlock_destroy()` 136 | 137 | Attempt to lock the spinlock (returns immediately with EBUSY if locked): 138 | `mthread_spinlock_trylock()` 139 | 140 | Lock the spinlock (blocks until spinlock is unlocked): 141 | `mthread_spinlock_lock()` 142 | 143 | Unlock the spinlock: 144 | `mthread_spinlock_unlock()` 145 | 146 | ### Mutexes 147 | 148 | Mutexes are used to prevent data inconsistencies due to race conditions (when two or more threads need to perform operations on the same memory area, but the results of computations depends on the order in which these operations are performed). Mutexes are used for serializing shared resources. Anytime a global resource is accessed by more than one thread the resource should have a mutex associated with it. One can apply a mutex to protect a segment of memory ("critical region") from other threads. 149 | 150 | Functions used in conjunction with the mutex: 151 | 152 | Creating/Destroying: 153 | `mthread_mutex_t mutex = MTHREAD_MUTEX_INITIALIZER;` 154 | `mthread_mutex_init()` 155 | `mthread_mutex_destroy()` 156 | 157 | Attempt to lock the mutex (returns immediately with EBUSY if locked): 158 | `mthread_mutex_trylock()` 159 | 160 | Lock the mutex (blocks until mutex is unlocked): 161 | `mthread_mutex_lock()` 162 | 163 | Unlock the mutex: 164 | `mthread_mutex_unlock()` 165 | 166 | ### Condition Variable 167 | 168 | While mutexes implement synchronization by controlling thread access to data, condition variables allow threads to synchronize based upon the actual value of data. The condition variable mechanism allows threads to suspend execution and relinquish the processor until some condition is true. A condition variable must always be associated with a mutex to avoid a race condition created by one thread preparing to wait and another thread which may signal the condition before the first thread actually waits on it resulting in a deadlock. The thread will be perpetually waiting for a signal that is never sent. Any mutex can be used, there is no explicit link between the mutex and the condition variable. 169 | 170 | Functions used in conjunction with the condition variable: 171 | 172 | Creating/Destroying: 173 | `mthread_cond_t cond = MTHREAD_COND_INITIALIZER;` 174 | `mthread_cond_init()` 175 | `mthread_cond_destroy()` 176 | 177 | Waiting on condition: 178 | `mthread_cond_wait()` 179 | 180 | Waking thread based on condition: 181 | `mthread_cond_signal()` 182 | 183 | ### Semaphores 184 | 185 | A Semaphore is a thread synchronization construct that can be used either to send signals between threads to avoid missed signals, or to guard a critical section like you would with a lock. Semaphores are also specifically designed to support an efficient waiting mechanism. If a thread can’t proceed until some change occurs, it is undesirable for that thread to be looping and repeatedly checking the state until it changes. In this case semaphore can be used to represent the right of a thread to proceed. A non-zero value means the thread 186 | should continue, zero means to hold off. When a thread attempts to decrement a unavailable semaphore (with a zero value), it efficiently waits until another thread increments the semaphore to signal the state change that will allow it to proceed. 187 | 188 | Functions used in conjunction with the semaphore: 189 | 190 | Creating/Destroying: 191 | `mthread_sem_t sem = MTHREAD_SEM_INITIALIZER;` 192 | `mthread_sem_init()` 193 | `mthread_sem_destroy()` 194 | 195 | Waiting on condition: 196 | `mthread_sem_wait()` 197 | 198 | Waking thread based on condition: 199 | `mthread_sem_post()` 200 | -------------------------------------------------------------------------------- /one-one/docs/logo.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/mayank-02/multithreading-library/3df2df3068c80851103e1d910e0d21b5ac8918ff/one-one/docs/logo.png -------------------------------------------------------------------------------- /one-one/docs/one-to-one.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/mayank-02/multithreading-library/3df2df3068c80851103e1d910e0d21b5ac8918ff/one-one/docs/one-to-one.png -------------------------------------------------------------------------------- /one-one/include/mthread.h: -------------------------------------------------------------------------------- 1 | #ifndef _MTHREAD_H_ 2 | #define _MTHREAD_H_ 3 | 4 | #include "types.h" 5 | 6 | #define MTHREAD_ATTR_DEFAULT NULL 7 | 8 | enum { 9 | DETACHED, 10 | JOINABLE, 11 | JOINED 12 | }; 13 | 14 | enum { 15 | MTHREAD_ATTR_GET, 16 | MTHREAD_ATTR_SET 17 | }; 18 | 19 | enum { 20 | MTHREAD_ATTR_NAME, /* RW [char *] name of thread */ 21 | MTHREAD_ATTR_JOINABLE, /* RW [int] detachment type */ 22 | MTHREAD_ATTR_STACK_SIZE, /* RW [size_t] stack */ 23 | MTHREAD_ATTR_STACK_ADDR /* RW [void *] stack lower */ 24 | }; 25 | 26 | /* Thread attribute functions */ 27 | struct mthread_attr; 28 | typedef struct mthread_attr mthread_attr_t; 29 | 30 | mthread_attr_t *mthread_attr_new(void); 31 | 32 | int mthread_attr_init(mthread_attr_t *attr); 33 | 34 | int mthread_attr_set(mthread_attr_t *attr, int field, ...); 35 | 36 | int mthread_attr_get(mthread_attr_t *attr, int field, ...); 37 | 38 | int mthread_attr_destroy(mthread_attr_t *attr); 39 | 40 | /* Thread control functions */ 41 | 42 | /** 43 | * Initialise the threading library 44 | */ 45 | int mthread_init(void); 46 | 47 | /** 48 | * Create a new thread starting at the routine given, which will 49 | * be passed arg. 50 | */ 51 | int mthread_create(mthread_t *thread, mthread_attr_t *attr, void *(*start_routine)(void *), void *arg); 52 | 53 | /** 54 | * Wait until the specified thread has exited. 55 | * Returns the value returned by that thread's 56 | * start function. 57 | */ 58 | int mthread_join(mthread_t thread, void **retval); 59 | 60 | /** 61 | * Yield to scheduler 62 | */ 63 | void mthread_yield(void); 64 | 65 | /** 66 | * Exit the calling thread with return value retval. 67 | */ 68 | void mthread_exit(void *retval); 69 | 70 | /** 71 | * Send signal specified by sig to thread 72 | */ 73 | int mthread_kill(mthread_t thread, int sig); 74 | 75 | /** 76 | * Mark the thread as detached 77 | */ 78 | int mthread_detach(mthread_t thread); 79 | 80 | /** 81 | * Compare Thread IDs 82 | */ 83 | int mthread_equal(mthread_t t1, mthread_t t2); 84 | 85 | 86 | /* Synchronisation primitives */ 87 | struct mthread_spinlock; 88 | typedef struct mthread_spinlock mthread_spinlock_t; 89 | 90 | /* 91 | * Initialise the spinlock 92 | */ 93 | int mthread_spin_init(mthread_spinlock_t *lock); 94 | 95 | /* 96 | * Lock the spinlock 97 | */ 98 | int mthread_spin_lock(mthread_spinlock_t *lock); 99 | 100 | /* 101 | * Try locking the spinlock 102 | */ 103 | int mthread_spin_trylock(mthread_spinlock_t *lock); 104 | 105 | /* 106 | * Unlock the spinlock 107 | */ 108 | int mthread_spin_unlock(mthread_spinlock_t *lock); 109 | 110 | #define MTHREAD_MUTEX_INITIALIZER { 0 } 111 | struct mthread_mutex; 112 | typedef struct mthread_mutex mthread_mutex_t; 113 | 114 | /* 115 | * Initialise the mutex 116 | */ 117 | int mthread_mutex_init(mthread_mutex_t *mutex); 118 | 119 | /* 120 | * Try locking the mutex 121 | */ 122 | int mthread_mutex_trylock(mthread_mutex_t *mutex); 123 | 124 | /* 125 | * Lock the mutex 126 | */ 127 | int mthread_mutex_lock(mthread_mutex_t *mutex); 128 | 129 | /* 130 | * Unlock the mutex 131 | */ 132 | int mthread_mutex_unlock(mthread_mutex_t *mutex); 133 | 134 | #define MTHREAD_COND_INITIALIZER { 0 , 0 } 135 | struct mthread_cond; 136 | typedef struct mthread_cond mthread_cond_t; 137 | 138 | int mthread_cond_init(mthread_cond_t *cond); 139 | 140 | int mthread_cond_wait(mthread_cond_t *cond, mthread_mutex_t *mutex); 141 | 142 | int mthread_cond_signal(mthread_cond_t *cond); 143 | 144 | #define MTHREAD_SEM_INITIALIZER { 0 } 145 | struct mthread_sem; 146 | typedef struct mthread_sem mthread_sem_t; 147 | 148 | int mthread_sem_init(mthread_sem_t *sem, uint32_t initval); 149 | 150 | int mthread_sem_wait(mthread_sem_t *sem); 151 | 152 | int mthread_sem_post(mthread_sem_t *sem); 153 | 154 | #endif -------------------------------------------------------------------------------- /one-one/include/queue.h: -------------------------------------------------------------------------------- 1 | #include "mthread.h" 2 | 3 | /// Node of a queue 4 | typedef struct node { 5 | /// TCB 6 | mthread *thd; 7 | /// Pointer to next node 8 | struct node *next; 9 | } node; 10 | 11 | /// Queue 12 | typedef struct queue { 13 | /// Count of nodes in the queue 14 | int count; 15 | /// Pointer to head node 16 | node *head; 17 | /// Pointer to tail node 18 | node *tail; 19 | } queue; 20 | 21 | void initialize(queue *q); 22 | 23 | int isempty(queue *q); 24 | 25 | void enqueue(queue *q, mthread *thd); 26 | 27 | mthread *dequeue(queue *q); 28 | 29 | int getcount(queue *q); 30 | 31 | void display(queue *q); 32 | 33 | mthread *search_on_tid(queue *q, mthread_t tid); 34 | 35 | int destroy(queue *q); -------------------------------------------------------------------------------- /one-one/include/stack.h: -------------------------------------------------------------------------------- 1 | #ifndef _STACK_H_ 2 | #define _STACK_H_ 3 | 4 | size_t get_page_size(void); 5 | 6 | size_t get_stack_size(void); 7 | 8 | void * allocate_stack(size_t stack_size); 9 | 10 | int deallocate_stack(void *base, size_t stack_size); 11 | 12 | #endif -------------------------------------------------------------------------------- /one-one/include/types.h: -------------------------------------------------------------------------------- 1 | #ifndef _TYPES_H_ 2 | #define _TYPES_H_ 3 | 4 | #include 5 | #include 6 | #include 7 | 8 | /// Maximium length of name of thread 9 | #define MTHREAD_TCB_NAMELEN 64 10 | 11 | /// Thread Handle 12 | typedef pid_t mthread_t; 13 | 14 | /// Thread Control Block 15 | typedef struct mthread { 16 | /// Thread ID 17 | mthread_t tid; 18 | 19 | /// Futex 20 | int32_t futex; 21 | 22 | /// Start position of the code to be executed 23 | void *(*start_routine) (void *); 24 | 25 | /// The argument passed to the function 26 | void *arg; 27 | 28 | /// The result of the thread function 29 | void *result; 30 | 31 | /// Padding for stack canary 32 | int64_t padding; 33 | 34 | /// Base pointer to stack 35 | void *stack_base; 36 | 37 | /// Size of stack 38 | size_t stack_size; 39 | 40 | /// Detachment type 41 | int detach_state; 42 | 43 | /// Name of process for debugging 44 | char name[MTHREAD_TCB_NAMELEN]; 45 | 46 | /// For exiting safely 47 | sigjmp_buf context; 48 | } mthread; 49 | 50 | /// Thread Attribute Structure 51 | struct mthread_attr { 52 | /// Name for debugging 53 | char a_name[MTHREAD_TCB_NAMELEN]; 54 | 55 | /// Detachment type 56 | int a_detach_state; 57 | 58 | /// Base pointer to stack 59 | void *a_stack_base; 60 | 61 | /// Size of stack 62 | size_t a_stack_size; 63 | }; 64 | 65 | /// States of a lock 66 | #define CONTESTED (2u) 67 | #define LOCKED (1u) 68 | #define UNLOCKED (0u) 69 | 70 | /// Spinlock structure 71 | struct mthread_spinlock { 72 | /// Value of spinlock 73 | int value; 74 | }; 75 | 76 | /// Mutex structure 77 | struct mthread_mutex { 78 | /// Value of mutex 79 | int value; 80 | }; 81 | 82 | /// Condition Variable structure 83 | struct mthread_cond { 84 | /// Current value of condition variable 85 | int value; 86 | 87 | /// Previous value of condition variable 88 | unsigned int previous; 89 | }; 90 | 91 | /// Semaphore structure 92 | struct mthread_sem { 93 | /// Value of semaphore 94 | int value; 95 | }; 96 | 97 | #endif -------------------------------------------------------------------------------- /one-one/include/utils.h: -------------------------------------------------------------------------------- 1 | #ifndef _UTILS_H_ 2 | #define _UTILS_H_ 3 | 4 | #include 5 | 6 | size_t get_extant_process_limit(void); 7 | 8 | char *util_strncpy(char *dst, const char *src, size_t dst_size); 9 | 10 | #endif -------------------------------------------------------------------------------- /one-one/run_tests.sh: -------------------------------------------------------------------------------- 1 | #!/bin/bash 2 | 3 | echo -e "\033[34m************************RUNNING ROBUST TEST*************************\033[0m" 4 | echo "./bin/robust_test" 5 | ./bin/robust_test 6 | echo "" 7 | echo "" 8 | echo -e "\033[34m***********************RUNNING SPINLOCK TEST************************\033[0m" 9 | echo "./bin/spin_test" 10 | ./bin/spin_test 11 | echo "5 seconds" 12 | ./bin/spin_test 5 13 | echo "" 14 | echo "" 15 | echo -e "\033[34m***********************RUNNING MUTEX TEST************************\033[0m" 16 | echo "./bin/mutex_test" 17 | ./bin/mutex_test 18 | echo "5 seconds" 19 | ./bin/mutex_test 5 20 | echo "" 21 | echo "" 22 | echo -e "\033[34m***********************RUNNING CONDVAR TEST************************\033[0m" 23 | echo "./bin/condvar_test" 24 | ./bin/condvar_test 25 | echo "" 26 | echo "" 27 | echo -e "\033[34m***********************RUNNING SEMAPHORE TEST************************\033[0m" 28 | echo "./bin/semaphore_test" 29 | ./bin/semaphore_test 30 | echo "1 10 10" 31 | ./bin/semaphore_test 1 10 10 32 | echo "" 33 | echo "" 34 | echo -e "\033[34m**********************RUNNING PERFORMANCE TEST**********************\033[0m" 35 | echo "./bin/performance_test" 36 | ./bin/performance_test 37 | echo "" 38 | echo "" 39 | echo -e "\033[34m**********************RUNNING PHILOSOPHERS TEST**********************\033[0m" 40 | echo "./bin/philosophers" 41 | ./bin/philosophers 42 | echo "2000 steps" 43 | ./bin/philosophers 2000 44 | echo "" 45 | echo "" -------------------------------------------------------------------------------- /one-one/src/attr.c: -------------------------------------------------------------------------------- 1 | /** 2 | * @file attr.c 3 | * @brief Attribute handling functions 4 | * @author Mayank Jain 5 | * @bug No known bugs 6 | */ 7 | 8 | #include 9 | #include 10 | #include 11 | #include 12 | #include "mthread.h" 13 | #include "utils.h" 14 | 15 | /** 16 | * @brief Controls the attributes depending on the operation 17 | * @param[in] cmd Get or Set the attribute 18 | * @param[in,out] a Attribute object 19 | * @param[in] op Attribute 20 | * @param[in] ap Variable argument list corresponding to attribute 21 | * @return On success, returns 0; on error, it returns an error number 22 | */ 23 | static int mthread_attr_ctrl(int cmd, mthread_attr_t *a, int op, va_list ap) { 24 | if(a == NULL) 25 | return EINVAL; 26 | switch(op) { 27 | case MTHREAD_ATTR_NAME: { 28 | /* name */ 29 | if(cmd == MTHREAD_ATTR_SET) { 30 | char *src, *dst; 31 | src = va_arg(ap, char *); 32 | dst = a->a_name; 33 | util_strncpy(dst, src, MTHREAD_TCB_NAMELEN); 34 | } 35 | else { 36 | char *src, **dst; 37 | src = a->a_name; 38 | dst = va_arg(ap, char **); 39 | *dst = src; 40 | } 41 | break; 42 | } 43 | case MTHREAD_ATTR_JOINABLE: { 44 | /* detachment type */ 45 | int val, *src, *dst; 46 | if(cmd == MTHREAD_ATTR_SET) { 47 | src = &val; 48 | val = va_arg(ap, int); 49 | dst = &a->a_detach_state; 50 | } 51 | else { 52 | src = &a->a_detach_state; 53 | dst = va_arg(ap, int *); 54 | } 55 | *dst = *src; 56 | break; 57 | } 58 | case MTHREAD_ATTR_STACK_SIZE: { 59 | /* stack size */ 60 | size_t val, *src, *dst; 61 | if(cmd == MTHREAD_ATTR_SET) { 62 | src = &val; 63 | val = va_arg(ap, size_t); 64 | dst = &a->a_stack_size; 65 | } 66 | else { 67 | src = &a->a_stack_size; 68 | dst = va_arg(ap, size_t *); 69 | } 70 | *dst = *src; 71 | break; 72 | } 73 | case MTHREAD_ATTR_STACK_ADDR: { 74 | /* stack address */ 75 | void *val, **src, **dst; 76 | if(cmd == MTHREAD_ATTR_SET) { 77 | src = &val; 78 | val = va_arg(ap, void *); 79 | dst = &a->a_stack_base; 80 | } 81 | else { 82 | src = &a->a_stack_base; 83 | dst = va_arg(ap, void **); 84 | } 85 | *dst = *src; 86 | break; 87 | } 88 | default: 89 | return EINVAL; 90 | } 91 | return 0; 92 | } 93 | 94 | /** 95 | * @brief Make a new thread attributes object and initialise it 96 | * @return On success, returns pointer to attribute object; 97 | * on error, it returns NULL 98 | */ 99 | mthread_attr_t *mthread_attr_new(void) { 100 | mthread_attr_t *a; 101 | a = (mthread_attr_t *) calloc(1, sizeof(mthread_attr_t)); 102 | if(a == NULL) { 103 | return NULL; 104 | } 105 | 106 | mthread_attr_init(a); 107 | return a; 108 | } 109 | 110 | /** 111 | * @brief Controls the attributes depending on the operation 112 | * @param[in,out] a Attribute object to be initialised 113 | * @return On success, returns 0; on error, it returns an error number 114 | */ 115 | int mthread_attr_init(mthread_attr_t *a) { 116 | if(a == NULL) 117 | return EINVAL; 118 | 119 | util_strncpy(a->a_name, "Unknown", MTHREAD_TCB_NAMELEN); 120 | a->a_detach_state = JOINABLE; 121 | a->a_stack_size = 8196 * 1024; 122 | a->a_stack_base = NULL; 123 | 124 | return 0; 125 | } 126 | 127 | /** 128 | * @brief Get particular attribute from thread attribute object 129 | * @param[in] a Attribute object 130 | * @param[in] op Attribute 131 | * @param[in] ... Variable argument list corresponding to attribute 132 | * @return On success, returns 0; on error, it returns an error number 133 | */ 134 | int mthread_attr_get(mthread_attr_t *a, int op, ...) { 135 | va_list ap; 136 | int ret; 137 | 138 | va_start(ap, op); 139 | ret = mthread_attr_ctrl(MTHREAD_ATTR_GET, a, op, ap); 140 | va_end(ap); 141 | return ret; 142 | } 143 | 144 | /** 145 | * @brief Set particular attribute in thread attribute object 146 | * @param[in,out] a Attribute object 147 | * @param[in] op Attribute 148 | * @param[in] ... Variable argument list corresponding to attribute 149 | * @return On success, returns 0; on error, it returns an error number 150 | */ 151 | int mthread_attr_set(mthread_attr_t *a, int op, ...) { 152 | va_list ap; 153 | int ret; 154 | 155 | va_start(ap, op); 156 | ret = mthread_attr_ctrl(MTHREAD_ATTR_SET, a, op, ap); 157 | va_end(ap); 158 | return ret; 159 | } 160 | 161 | /** 162 | * @brief Destroy thread attribute 163 | * @param[in,out] a Attribute object 164 | * @return On success, returns 0; on error, it returns an error number 165 | */ 166 | int mthread_attr_destroy(mthread_attr_t *a) { 167 | if(a == NULL) 168 | return EINVAL; 169 | free(a); 170 | return 0; 171 | } -------------------------------------------------------------------------------- /one-one/src/cond.c: -------------------------------------------------------------------------------- 1 | /** 2 | * @file cond.c 3 | * @brief Condition Variable Synchronisation Primitive 4 | * @author Mayank Jain 5 | * @bug No known bugs 6 | */ 7 | 8 | #define _GNU_SOURCE 9 | #include 10 | #include 11 | #include 12 | #include 13 | #include 14 | #include 15 | #include "mthread.h" 16 | 17 | /** 18 | * @brief Fast user-space locking 19 | * @param[in] uaddr Pointer to futex word 20 | * @param[in] futex_op Operation to be performed 21 | * @param[in] val Expected value of the futex word 22 | * @return 0 on success; -1 on error 23 | */ 24 | static inline int futex(int *uaddr, int futex_op, int val) { 25 | return syscall(SYS_futex, uaddr, futex_op, val, NULL, NULL, 0); 26 | } 27 | 28 | /** 29 | * @brief Initialise the condition variable 30 | * @param[in,out] cond Pointer to condition variable 31 | * @return Always returns 0 32 | */ 33 | int mthread_cond_init(mthread_cond_t *cond) { 34 | assert(cond); 35 | 36 | atomic_init(&cond->value, 0); 37 | atomic_init(&cond->previous, 0); 38 | 39 | return 0; 40 | } 41 | 42 | /** 43 | * @brief Atomically unlocks the mutex and waits for CV to be signaled 44 | * @param[in,out] cond Pointer to condition variable 45 | * @param[in,out] mutex Pointer to associated mutex 46 | * @note The thread execution is suspended and does not consume any 47 | * CPU time until the condition variable is signaled. 48 | * @return On success, returns 0 49 | */ 50 | int mthread_cond_wait(mthread_cond_t *cond, mthread_mutex_t *mutex) { 51 | assert(cond && mutex); 52 | 53 | int value = atomic_load(&cond->value); 54 | atomic_store(&cond->previous, value); 55 | 56 | mthread_mutex_unlock(mutex); 57 | futex(&cond->value, FUTEX_WAIT_PRIVATE, value); 58 | mthread_mutex_lock(mutex); 59 | 60 | return 0; 61 | } 62 | 63 | /** 64 | * @brief Restarts one of the threads that are waiting 65 | * on the condition variable 66 | * @param[in,out] cond Pointer to condition variable 67 | * @return On success, returns 0 68 | */ 69 | int mthread_cond_signal(mthread_cond_t *cond) { 70 | assert(cond); 71 | 72 | unsigned value = 1u + atomic_load(&cond->previous); 73 | atomic_store(&cond->value, value); 74 | 75 | futex(&cond->value, FUTEX_WAKE_PRIVATE, 1); 76 | 77 | return 0; 78 | } -------------------------------------------------------------------------------- /one-one/src/mthread.c: -------------------------------------------------------------------------------- 1 | /** 2 | * @file mthread.c 3 | * @brief Thread control functions 4 | * @author Mayank Jain 5 | * @bug No known bugs 6 | */ 7 | 8 | #define _GNU_SOURCE 9 | #include 10 | #include 11 | #include 12 | #include 13 | #include 14 | #include 15 | #include 16 | #include 17 | #include 18 | #include 19 | #include 20 | #include "queue.h" 21 | #include "stack.h" 22 | #include "mthread.h" 23 | #include "utils.h" 24 | 25 | static size_t nproc; ///< Number of extant processes allowed 26 | static size_t stack_size; ///< Stack size 27 | static size_t page_size; ///< Page size 28 | static queue * task_q; ///< Queue containing tasks for all threads 29 | static mthread_spinlock_t lock; ///< Lock for task queue 30 | 31 | /** 32 | * @brief Fast user-space locking 33 | * @param[in] uaddr Pointer to futex word 34 | * @param[in] futex_op Operation to be performed 35 | * @param[in] val Expected value of the futex word 36 | * @return 0 on success; -1 on error 37 | */ 38 | static inline int futex(int *uaddr, int futex_op, int val) { 39 | return syscall(SYS_futex, uaddr, futex_op, val, NULL, NULL, 0); 40 | } 41 | 42 | /** 43 | * @brief Get/Set architecture-specific thread state 44 | * @param[in] code Subfunction 45 | * @param[in/out] Address of value to "set" or "get" 46 | * @return On success, returns 0; on error, -1 is returned, and errno is set to indicate the error. 47 | */ 48 | static inline int arch_prctl(int code, unsigned long *addr) { 49 | return syscall(SYS_arch_prctl, code, addr); 50 | } 51 | 52 | /** 53 | * @brief Sends a signal to a thread 54 | * @param[in] tgid Thread Group ID 55 | * @param[in] tid Thread ID 56 | * @param[in] sig Signal number 57 | * @return 0 on success; -1 on error 58 | */ 59 | static inline int tgkill(int tgid, int tid, int sig) { 60 | return syscall(SYS_tgkill, tgid, tid, sig); 61 | } 62 | 63 | /** 64 | * @brief Cleans up all malloc(3)ed and mmap(3)ed regions 65 | */ 66 | static void cleanup_handler(void) { 67 | mthread *t; 68 | int n = getcount(task_q); 69 | while(n--) { 70 | t = dequeue(task_q); 71 | if(t->detach_state == JOINED) { 72 | deallocate_stack(t->stack_base, t->stack_size); 73 | free(t); 74 | } 75 | } 76 | free(task_q); 77 | } 78 | 79 | /** 80 | * @brief Obtain information about calling thread 81 | * @return Pointer to thread handle on success, and NULL on failure 82 | */ 83 | static mthread *mthread_self(void) { 84 | uint64_t ptr; 85 | pid_t tid = gettid(); 86 | if(tid == getpid()){ 87 | return NULL; 88 | } 89 | 90 | int err = arch_prctl(ARCH_GET_FS, &ptr); 91 | if(err == -1) 92 | return NULL; 93 | 94 | return (mthread *)ptr; 95 | } 96 | 97 | /** 98 | * @brief Wrapper around user start function 99 | * @return On success, returns 0 100 | */ 101 | static int mthread_start(void *thread) { 102 | mthread *t = (mthread *)thread; 103 | 104 | if(sigsetjmp(t->context, 0) == 0) 105 | t->result = t->start_routine(t->arg); 106 | 107 | return 0; 108 | } 109 | 110 | /** 111 | * @brief Initialise the mthread library 112 | * @note It has to be the first mthread API function call in an application, 113 | * and is mandatory. 114 | * @return On success, returns 0; on error, it returns an error number 115 | */ 116 | int mthread_init(void) { 117 | mthread_spin_init(&lock); 118 | 119 | task_q = calloc(1, sizeof(queue)); 120 | initialize(task_q); 121 | 122 | atexit(cleanup_handler); 123 | 124 | mthread *main_thread = (mthread *) calloc(1, sizeof(mthread)); 125 | main_thread->start_routine = main_thread->arg = main_thread->result = NULL; 126 | main_thread->detach_state = JOINABLE; 127 | main_thread->stack_base = NULL; 128 | main_thread->stack_size = 0; 129 | main_thread->tid = gettid(); 130 | enqueue(task_q, main_thread); 131 | 132 | stack_size = get_stack_size(); 133 | nproc = get_extant_process_limit(); 134 | page_size = get_page_size(); 135 | 136 | return 0; 137 | } 138 | 139 | /** 140 | * @brief Create a new thread 141 | * @param[in] thread Pointer to thread handle 142 | * @param[in] attr Pointer to attribute object 143 | * @param[in] start_routine Start function of the thread 144 | * @param[in] arg Arguments to be passed to the start function 145 | * @return On success, returns 0; on error, it returns an error number 146 | */ 147 | int mthread_create(mthread_t *thread, mthread_attr_t *attr, void *(*start_routine)(void *), void *arg) { 148 | mthread_spin_lock(&lock); 149 | 150 | if(getcount(task_q) == nproc) { 151 | mthread_spin_unlock(&lock); 152 | return EAGAIN; 153 | } 154 | 155 | if(start_routine == NULL) { 156 | mthread_spin_unlock(&lock); 157 | return EINVAL; 158 | } 159 | 160 | mthread *t = (mthread *) calloc(1, sizeof(mthread)); 161 | if(t == NULL) { 162 | mthread_spin_unlock(&lock); 163 | return EAGAIN; 164 | } 165 | 166 | t->start_routine = start_routine; 167 | t->arg = arg; 168 | t->detach_state = (attr == NULL ? JOINABLE : attr->a_detach_state); 169 | t->stack_size = (attr == NULL ? stack_size : attr->a_stack_size); 170 | t->stack_base = (attr == NULL ? NULL : attr->a_stack_base); 171 | if(t->stack_base == NULL) { 172 | t->stack_base = allocate_stack(t->stack_size); 173 | if(t->stack_base == NULL) { 174 | free(t); 175 | mthread_spin_unlock(&lock); 176 | return ENOMEM; 177 | } 178 | } 179 | 180 | if(attr == NULL) 181 | snprintf(t->name, MTHREAD_TCB_NAMELEN, "User%d", t->tid); 182 | else 183 | util_strncpy(t->name, attr->a_name, MTHREAD_TCB_NAMELEN); 184 | 185 | t->tid = clone(mthread_start, 186 | t->stack_base + t->stack_size, 187 | CLONE_VM | CLONE_FS | CLONE_FILES | 188 | CLONE_SIGHAND |CLONE_THREAD | CLONE_SYSVSEM | 189 | CLONE_SETTLS |CLONE_PARENT_SETTID | CLONE_CHILD_CLEARTID, 190 | t, 191 | &t->futex, 192 | t, 193 | &t->futex); 194 | if(t->tid == -1) { 195 | deallocate_stack(t->stack_base, t->stack_size); 196 | free(t); 197 | mthread_spin_unlock(&lock); 198 | return errno; 199 | } 200 | 201 | enqueue(task_q, t); 202 | 203 | *thread = t->tid; 204 | 205 | mthread_spin_unlock(&lock); 206 | return 0; 207 | } 208 | 209 | /** 210 | * @brief Join with a terminated thread 211 | * @param[in] thread Handle of thread to wait for 212 | * @param[in] retval To save the exit status of the target thread 213 | * @return On success, returns 0; on error, it returns an error number 214 | */ 215 | int mthread_join(mthread_t thread, void **retval) { 216 | mthread_spin_lock(&lock); 217 | 218 | mthread *target = search_on_tid(task_q, thread); 219 | if(target == NULL) { 220 | mthread_spin_unlock(&lock); 221 | return ESRCH; 222 | } 223 | 224 | if(target->detach_state == DETACHED || target->detach_state == JOINED) { 225 | mthread_spin_unlock(&lock); 226 | return EINVAL; 227 | } 228 | 229 | target->detach_state = JOINED; 230 | mthread_spin_unlock(&lock); 231 | 232 | int err = futex(&target->futex, FUTEX_WAIT, target->tid); 233 | if(err == -1 && errno != EAGAIN) 234 | return err; 235 | 236 | if(retval) 237 | *retval = target->result; 238 | 239 | return 0; 240 | } 241 | 242 | /** 243 | * @brief Yield the processor 244 | */ 245 | void mthread_yield(void) { 246 | sched_yield(); 247 | } 248 | 249 | /** 250 | * @brief Terminate calling thread 251 | * @param[in] retval Return value of the thread 252 | * @return Does not return to the caller 253 | * @note Performing a return from the start funciton of any thread results in 254 | * an implicit call to mthread_exit() 255 | */ 256 | void mthread_exit(void *retval) { 257 | mthread_spin_lock(&lock); 258 | mthread *self = mthread_self(); 259 | if(self == NULL) { 260 | mthread_spin_unlock(&lock); 261 | return; 262 | } 263 | 264 | self->result = retval; 265 | mthread_spin_unlock(&lock); 266 | siglongjmp(self->context, 1); 267 | } 268 | 269 | /** 270 | * @brief Send a signal to a thread 271 | * @param[in] thread Thread handle of thread to which signal needs to be sent 272 | * @param[in] sig Signal number corresponding to signal 273 | * @return On success, returns 0; on error, it returns an error number 274 | */ 275 | int mthread_kill(mthread_t thread, int sig) { 276 | if(sig == 0) 277 | return 0; 278 | 279 | pid_t tgid = getpid(); 280 | int err = tgkill(tgid, thread, sig); 281 | if(err == -1) 282 | return errno; 283 | 284 | return 0; 285 | } 286 | 287 | /** 288 | * @brief Detach a thread 289 | * @param[in] thread Thread handle of thread to be detached 290 | * @return On success, returns 0; on error, it returns an error number 291 | * @note Once a thread has been detached, it can't be joined with mthread_join * or be made joinable again. 292 | */ 293 | int mthread_detach(mthread_t thread) { 294 | mthread_spin_lock(&lock); 295 | 296 | mthread *target = search_on_tid(task_q, thread); 297 | 298 | if(target == NULL) { 299 | mthread_spin_unlock(&lock); 300 | return ESRCH; 301 | } 302 | 303 | if(target->detach_state == JOINED) { 304 | mthread_spin_unlock(&lock); 305 | return EINVAL; 306 | } 307 | 308 | target->detach_state = DETACHED; 309 | mthread_spin_unlock(&lock); 310 | 311 | return 0; 312 | } 313 | 314 | /** 315 | * @brief Compare Thread IDs 316 | * @param[in] t1 Thread handle of thread 1 317 | * @param[in] t2 Thread handle of thread 2 318 | * @return 0 on success, and non-zero on failure 319 | */ 320 | int mthread_equal(mthread_t t1, mthread_t t2) { 321 | return t1 - t2; 322 | } 323 | -------------------------------------------------------------------------------- /one-one/src/mutex.c: -------------------------------------------------------------------------------- 1 | /** 2 | * @file mutex.c 3 | * @brief Mutex Synchronisation Primitive 4 | * @author Mayank Jain 5 | * @bug No known bugs 6 | */ 7 | 8 | #define _GNU_SOURCE 9 | #include 10 | #include 11 | #include 12 | #include 13 | #include 14 | #include 15 | #include 16 | #include "mthread.h" 17 | 18 | /** 19 | * @brief Atomic Compare and Swap 20 | * @param[in,out] lock_addr Pointer to lock 21 | * @param[in] expected Expected value of lock 22 | * @param[in] desirec Desired value of lock 23 | * @return Upon success, the macro returns true. Upon failure, the desired 24 | * value is overwritten with the value of the atomic variable and false is 25 | * returned. 26 | */ 27 | static inline int atomic_cas(int *lock_addr, int expected, int desired) { 28 | return atomic_compare_exchange_strong(lock_addr, &expected, desired); 29 | } 30 | 31 | /** 32 | * @brief Fast user-space locking 33 | * @param[in] uaddr Pointer to futex word 34 | * @param[in] futex_op Operation to be performed 35 | * @param[in] val Expected value of the futex word 36 | * @return 0 on success; -1 on error 37 | */ 38 | static inline int futex(int *uaddr, int futex_op, int val) { 39 | return syscall(SYS_futex, uaddr, futex_op, val, NULL, NULL, 0); 40 | } 41 | 42 | /** 43 | * @brief Atomic Compare and Exchange 44 | * Atomically performs the equivalent of: 45 | * if (*ptr == *oldval) 46 | * *ptr = newval; 47 | * @param[in,out] lock_addr Pointer to lock 48 | * @param[in] expected Expected value of lock 49 | * @param[in] desirec Desired value of lock 50 | * @return Returns the expected value 51 | */ 52 | static inline int cmpxchg(int *lock_addr, int expected, int desired) { 53 | int *ep = &expected; 54 | atomic_compare_exchange_strong(lock_addr, ep, desired); 55 | return *ep; 56 | } 57 | 58 | /** 59 | * @brief Initialise the mutex 60 | * @param[in,out] mutex Pointer to mutex 61 | * @return Always returns 0 62 | */ 63 | int mthread_mutex_init(mthread_mutex_t *mutex) { 64 | assert(mutex); 65 | mutex->value = UNLOCKED; 66 | return 0; 67 | } 68 | 69 | /** 70 | * @brief Lock the mutex 71 | * @param[in,out] mutex Pointer to mutex 72 | * @note If the mutex is already locked by another thread, the 73 | * calling thread is suspended until the mutex is unlocked. 74 | * @return On success, returns 0 75 | */ 76 | int mthread_mutex_lock(mthread_mutex_t *mutex) { 77 | assert(mutex); 78 | 79 | int c = cmpxchg(&mutex->value, UNLOCKED, LOCKED); 80 | 81 | /* 82 | * If the lock was previously unlocked, there's nothing else for us to do. 83 | * Otherwise, we'll probably have to wait. 84 | */ 85 | if(c != 0) { 86 | do { 87 | 88 | /* 89 | * If the mutex is locked, we signal that we're waiting by setting 90 | * the mutex->value to 2. A shortcut checks is it's 2 already and 91 | * avoids the atomic operation in this case. 92 | */ 93 | if(c == 2 || cmpxchg(&mutex->value, LOCKED, CONTESTED) != 0) { 94 | 95 | /* 96 | * Here we have to actually sleep, because the mutex is actually 97 | * locked. Note that it's not necessary to loop around this 98 | * syscall; 99 | * A spurious wakeup will do no harm since we only exit the 100 | * do...while loop when mutex->value is indeed 0. 101 | */ 102 | futex(&mutex->value, FUTEX_WAIT, CONTESTED); 103 | } 104 | 105 | /* 106 | * We're here when either: 107 | * (a) the mutex was in fact unlocked (by an intervening thread). 108 | * (b) we slept waiting for the atom and were awoken. 109 | * 110 | * So we try to lock the atom again. We set the state to 2 because 111 | * we can't be certain there's no other thread at this exact point. 112 | * So we prefer to err on the safe side. 113 | */ 114 | } while((c = cmpxchg(&mutex->value, UNLOCKED, CONTESTED)) != 0); 115 | } 116 | return 0; 117 | } 118 | 119 | /** 120 | * @brief Try locking the mutex 121 | * @param[in,out] mutex Pointer to mutex 122 | * @note does not block the calling thread if the mutex is 123 | * already locked by another thread 124 | * @return On locking returns 0, else EBUSY 125 | */ 126 | int mthread_mutex_trylock(mthread_mutex_t *mutex) { 127 | assert(mutex); 128 | return atomic_cas(&mutex->value, UNLOCKED, UNLOCKED) ? 0 : EBUSY; 129 | } 130 | 131 | /** 132 | * @brief Unlock the mutex 133 | * @param[in,out] mutex Pointer to mutex 134 | * @return On success, returns 0 135 | */ 136 | int mthread_mutex_unlock(mthread_mutex_t *mutex) { 137 | assert(mutex); 138 | if(atomic_fetch_sub(&mutex->value, 1) != 1) { 139 | atomic_store(&mutex->value, UNLOCKED); 140 | futex(&mutex->value, FUTEX_WAKE, 1); 141 | } 142 | return 0; 143 | } -------------------------------------------------------------------------------- /one-one/src/queue.c: -------------------------------------------------------------------------------- 1 | /** 2 | * @file queue.c 3 | * @brief Singly linked queue for thread control blocks 4 | * @author Mayank Jain 5 | * @bug No known bugs 6 | */ 7 | 8 | #include 9 | #include 10 | #include 11 | #include "queue.h" 12 | 13 | /** 14 | * @brief Initialise the queue 15 | * @param[in] q Pointer to queue 16 | */ 17 | void initialize(queue *q) { 18 | q->count = 0; 19 | q->head = NULL; 20 | q->tail = NULL; 21 | } 22 | 23 | /** 24 | * @brief Check if queue is empty 25 | * @param[in] q Pointer to queue 26 | * @return If empty, returns 1; else 0 27 | */ 28 | int isempty(queue *q) { 29 | if(q->head == NULL) { 30 | assert(q->count == 0); 31 | assert(q->tail == 0); 32 | } 33 | return (q->head == NULL); 34 | } 35 | 36 | /** 37 | * @brief Enqueue a TCB in the queue 38 | * @param[in] q Pointer to queue 39 | * @param[in] thd Pointer to TCB 40 | */ 41 | void enqueue(queue *q, mthread *thd) { 42 | node *tmp = malloc(sizeof(node)); 43 | tmp->thd = thd; 44 | tmp->next = NULL; 45 | 46 | if(isempty(q)) { 47 | q->head = q->tail = tmp; 48 | } 49 | else { 50 | q->tail->next = tmp; 51 | q->tail = tmp; 52 | } 53 | q->count++; 54 | 55 | return; 56 | } 57 | 58 | /** 59 | * @brief Dequeue a TCB in the queue 60 | * @param[in] q Pointer to queue 61 | * @return Pointer to TCB dequeued; Return NULL if empty 62 | */ 63 | mthread *dequeue(queue *q) { 64 | if(isempty(q)) 65 | return NULL; 66 | 67 | node *tmp = q->head; 68 | mthread *n = q->head->thd; 69 | 70 | q->head = q->head->next; 71 | q->count--; 72 | 73 | if(q->head == NULL) { 74 | q->tail = NULL; 75 | } 76 | 77 | free(tmp); 78 | return(n); 79 | } 80 | 81 | /** 82 | * @brief Get count of TCBs in queue 83 | * @param[in] q Pointer to queue 84 | * @return Count 85 | */ 86 | int getcount(queue *q) { 87 | return q->count; 88 | } 89 | 90 | /** 91 | * @brief Display TCBs in queue 92 | * @param[in] q Pointer to queue 93 | */ 94 | void display(queue *q) { 95 | if(isempty(q)) 96 | return; 97 | 98 | node *runner = q->head; 99 | printf("Queue (%d): ", q->count); 100 | while(runner) { 101 | printf("%u ", runner->thd->tid); 102 | runner = runner->next; 103 | } 104 | printf("\n"); 105 | } 106 | 107 | /** 108 | * @brief Search for a TCB based on TID in the queue 109 | * @param[in] q Pointer to queue 110 | * @param[in] tid TID of the target thread 111 | * @return Pointer to target thread; Return NULL if empty 112 | */ 113 | mthread *search_on_tid(queue *q, mthread_t tid) { 114 | if(isempty(q)) 115 | return NULL; 116 | 117 | node *runner = q->head; 118 | while(runner) { 119 | if (runner->thd->tid == tid) { 120 | return runner->thd; 121 | } 122 | runner = runner->next; 123 | } 124 | return NULL; 125 | } 126 | 127 | /** 128 | * @brief Destroy the queue 129 | * @param[in] q Pointer to queue 130 | * @return On success, returns 0; on error, -1 is returned 131 | */ 132 | int destroy(queue *q) { 133 | if(!isempty(q)) 134 | return -1; 135 | 136 | free(q); 137 | return 0; 138 | } -------------------------------------------------------------------------------- /one-one/src/sem.c: -------------------------------------------------------------------------------- 1 | /** 2 | * @file sem.c 3 | * @brief Semaphore Synchronisation Primitive 4 | * @author Mayank Jain 5 | * @bug No known bugs 6 | */ 7 | 8 | #define _GNU_SOURCE 9 | #include 10 | #include 11 | #include 12 | #include 13 | #include 14 | #include 15 | #include "mthread.h" 16 | 17 | /** 18 | * @brief Fast user-space locking 19 | * @param[in] uaddr Pointer to futex word 20 | * @param[in] futex_op Operation to be performed 21 | * @param[in] val Expected value of the futex word 22 | * @return 0 on success; -1 on error 23 | */ 24 | static inline int futex(int *uaddr, int futex_op, int val) { 25 | return syscall(SYS_futex, uaddr, futex_op, val, NULL, NULL, 0); 26 | } 27 | 28 | /** 29 | * @brief Initialise the semaphore 30 | * @param[in,out] sem Pointer to semaphore 31 | * @param[in,out] initval Value to be initialised to 32 | * @return On success, returns 0 33 | */ 34 | int mthread_sem_init(mthread_sem_t *sem, uint32_t initval) { 35 | assert(sem); 36 | atomic_init(&sem->value, initval); 37 | return 0; 38 | } 39 | 40 | /** 41 | * @brief Decrements (locks) the semaphore 42 | * @param[in,out] sem Pointer to semaphore 43 | * @note If the semaphore currently has the value zero, then the 44 | * call blocks until it becomes possible to perform the decrement 45 | * @return On success, returns 0 46 | */ 47 | int mthread_sem_wait(mthread_sem_t *sem) { 48 | assert(sem); 49 | uint32_t value = 1; 50 | 51 | while(!atomic_compare_exchange_weak_explicit(&sem->value, 52 | &value, value - 1, 53 | memory_order_acquire, 54 | memory_order_relaxed)) { 55 | if(value == 0) { 56 | futex(&sem->value, FUTEX_WAIT_PRIVATE, 0); 57 | value = 1; 58 | } 59 | } 60 | 61 | return 0; 62 | } 63 | 64 | /** 65 | * @brief Increments (unlocks) the semaphore 66 | * @param[in,out] sem Pointer to semaphore 67 | * @return On success, returns 0 68 | */ 69 | int mthread_sem_post(mthread_sem_t *sem) { 70 | assert(sem); 71 | atomic_fetch_add_explicit(&sem->value, 1, memory_order_release); 72 | futex(&sem->value, FUTEX_WAKE_PRIVATE, 1); 73 | return 0; 74 | } -------------------------------------------------------------------------------- /one-one/src/spin_lock.c: -------------------------------------------------------------------------------- 1 | /** 2 | * @file spin_lock.c 3 | * @brief Spinlock Synchronisation Primitive 4 | * @author Mayank Jain 5 | * @bug No known bugs 6 | */ 7 | 8 | #include 9 | #include 10 | #include 11 | #include "mthread.h" 12 | 13 | /** 14 | * @brief Atomic Compare and Swap 15 | * @param[in,out] lock_addr Pointer to lock 16 | * @param[in] expected Expected value of lock 17 | * @param[in] desirec Desired value of lock 18 | * @return Upon success, the macro returns true. Upon failure, the desired 19 | * value is overwritten with the value of the atomic variable and false is 20 | * returned. 21 | */ 22 | static inline int atomic_cas(int *lock_addr, int expected, int desired) { 23 | return atomic_compare_exchange_strong(lock_addr, &expected, desired); 24 | } 25 | 26 | /** 27 | * @brief Initialise the spinlock 28 | * @param[out] lock Pointer to the spinlock 29 | * @note Reinitialization of a lock held by other threads may lead to 30 | * unexpected results, hence this function must be called only once 31 | * @return On success, returns 0; on error, it returns an error number 32 | */ 33 | int mthread_spin_init(mthread_spinlock_t *lock) { 34 | assert(lock); 35 | lock->value = UNLOCKED; 36 | return 0; 37 | } 38 | 39 | /** 40 | * @brief Lock a spinlock 41 | * @param[in,out] lock Pointer to the spinlock 42 | * @note The call is blocking and will return only if the lock is acquired 43 | * @return On success, returns 0; on error, it returns an error number 44 | */ 45 | int mthread_spin_lock(mthread_spinlock_t *lock) { 46 | assert(lock); 47 | while (!atomic_cas(&lock->value, UNLOCKED, LOCKED)); 48 | return 0; 49 | } 50 | 51 | /** 52 | * @brief Try locking a spinlock 53 | * @param[in,out] lock Pointer to the spinlock 54 | * @note The call returns immediately if acquiring lock fails 55 | * @return On success, returns 0; on error, it returns an error number 56 | */ 57 | int mthread_spin_trylock(mthread_spinlock_t *lock) { 58 | assert(lock); 59 | if(atomic_cas(&lock->value, UNLOCKED, LOCKED)) 60 | return 0; 61 | 62 | return EBUSY; 63 | } 64 | 65 | /** 66 | * @brief Unlock a spinlock 67 | * @param[in,out] lock Pointer to the spinlock 68 | * @note Calling mthread_spin_unlock() on a lock that is not held by the 69 | * caller results in undefined behavior. 70 | * @return On success, returns 0; on error, it returns an error number 71 | */ 72 | int mthread_spin_unlock(mthread_spinlock_t *lock) { 73 | assert(lock); 74 | atomic_cas(&lock->value, LOCKED, UNLOCKED); 75 | return 0; 76 | } -------------------------------------------------------------------------------- /one-one/src/stack.c: -------------------------------------------------------------------------------- 1 | /** 2 | * @file stack.c 3 | * @brief Thread stack allocation and deallocation functions 4 | * @author Mayank Jain 5 | * @bug No known bugs 6 | */ 7 | 8 | #include 9 | #include 10 | #include 11 | #include 12 | #include "stack.h" 13 | 14 | /** 15 | * @brief Get the stack size of a thread 16 | * @return Size in bytes 17 | */ 18 | size_t get_stack_size(void) { 19 | struct rlimit limit; 20 | getrlimit(RLIMIT_STACK, &limit); 21 | return limit.rlim_cur; 22 | } 23 | 24 | /** 25 | * @brief Get the page size of a thread 26 | * @return Size in bytes 27 | */ 28 | size_t get_page_size(void) { 29 | return sysconf(_SC_PAGESIZE); 30 | } 31 | 32 | /** 33 | * @brief Allocate a stack 34 | * @param[in] stack_size Size of stack to mmap 35 | * @return Pointer to the base of the stack 36 | */ 37 | void * allocate_stack(size_t stack_size) { 38 | size_t page_size = get_page_size(); 39 | 40 | void *base = mmap(NULL, 41 | stack_size + page_size, 42 | PROT_READ | PROT_WRITE, 43 | MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, 44 | -1, 45 | 0); 46 | if(base == MAP_FAILED) 47 | return NULL; 48 | 49 | if(mprotect(base, page_size, PROT_NONE) == -1) { 50 | munmap(base, stack_size + page_size); 51 | return NULL; 52 | } 53 | 54 | return base + page_size; 55 | } 56 | 57 | /** 58 | * @brief Deallocate a stack 59 | * @param[in] base Base of the stack 60 | * @param[in] stack_size Size of stack to mmap 61 | * @return On success, returns 0; On error, returns -1 62 | */ 63 | int deallocate_stack(void *base, size_t stack_size) { 64 | size_t page_size = get_page_size(); 65 | return munmap(base - page_size, stack_size + page_size); 66 | } -------------------------------------------------------------------------------- /one-one/src/utils.c: -------------------------------------------------------------------------------- 1 | /** 2 | * @file utils.c 3 | * @brief Utility functions 4 | * @author Mayank Jain 5 | * @bug No known bugs 6 | */ 7 | 8 | #include 9 | #include "utils.h" 10 | 11 | /** 12 | * @brief Get the limit of extant processes 13 | * @return Extant process limiit 14 | */ 15 | size_t get_extant_process_limit(void) { 16 | struct rlimit limit; 17 | getrlimit(RLIMIT_NPROC, &limit); 18 | return limit.rlim_cur; 19 | } 20 | 21 | /** 22 | * @brief Copy a string of length atmost n bytes including '\0' character 23 | * @param[in,out] dst String to be copied into 24 | * @param[in] src String to be copied from 25 | * @param[in] dst_size Number of characters to copy 26 | * @return Pointer to first character of destination string 27 | */ 28 | char *util_strncpy(char *dst, const char *src, size_t dst_size) { 29 | if(dst_size == 0) 30 | return dst; 31 | 32 | char *d = dst; 33 | char *end = dst + dst_size - 1; 34 | 35 | while(d < end) { 36 | if((*d = *src) == '\0') 37 | return dst; 38 | d++; 39 | src++; 40 | } 41 | *d = '\0'; 42 | 43 | return dst; 44 | } -------------------------------------------------------------------------------- /one-one/test/condvar_test.c: -------------------------------------------------------------------------------- 1 | /** 2 | * Example code for using mthread condition variables. The main thread 3 | * creates three threads. Two of those threads increment a "count" variable, 4 | * while the third thread watches the value of "count". When "count" 5 | * reaches a predefined limit, the waiting thread is signaled by one of the 6 | * incrementing threads. The waiting thread "awakens" and then modifies 7 | * count. The program continues until the incrementing threads reach 8 | * TCOUNT. The main program prints the final value of count. 9 | */ 10 | 11 | #include "mthread.h" 12 | #include 13 | #include 14 | #include 15 | #include 16 | 17 | #define MCHECK(FCALL) \ 18 | { \ 19 | int result; \ 20 | if ((result = (FCALL)) != 0) { \ 21 | fprintf(stderr, "FATAL: %s (%s)", strerror(result), #FCALL); \ 22 | exit(-1); \ 23 | } \ 24 | } 25 | 26 | #define NUM_THREADS 3 27 | #define TCOUNT 10 28 | #define COUNT_LIMIT 12 29 | 30 | int count = 0; 31 | mthread_mutex_t count_mutex; 32 | mthread_cond_t count_threshold_cv; 33 | 34 | void *inc_count(void *t) { 35 | int i; 36 | long my_id = (long)t; 37 | 38 | for (i = 0; i < TCOUNT; i++) { 39 | mthread_mutex_lock(&count_mutex); 40 | count++; 41 | 42 | /* 43 | * Check the value of count and signal waiting thread when condition is 44 | * reached. Note that this occurs while mutex is locked. 45 | */ 46 | 47 | if (count == COUNT_LIMIT) { 48 | printf("inc_count() : thread %ld, count = %d, threshold reached. ", 49 | my_id, count); 50 | mthread_cond_signal(&count_threshold_cv); 51 | printf("Just sent signal.\n"); 52 | } 53 | printf("inc_count() : thread %ld, count = %d, unlocking mutex\n", 54 | my_id, count); 55 | mthread_mutex_unlock(&count_mutex); 56 | 57 | /* Do some work so threads can alternate on mutex lock */ 58 | sleep(1); 59 | } 60 | mthread_exit(NULL); 61 | } 62 | 63 | void *watch_count(void *t) { 64 | long my_id = (long)t; 65 | 66 | printf("Starting watch_count(): thread %ld\n", my_id); 67 | 68 | /** 69 | * Lock mutex and wait for signal. Note that the mthread_cond_wait routine 70 | * will automatically and atomically unlock mutex while it waits. 71 | * Also, note that if COUNT_LIMIT is reached before this routine is run by 72 | * the waiting thread, the loop will be skipped to prevent mthread_cond_wait 73 | * from never returning. 74 | */ 75 | mthread_mutex_lock(&count_mutex); 76 | 77 | while (count < COUNT_LIMIT) { 78 | printf("watch_count(): thread %ld, count = %d, Going into wait...\n", my_id, count); 79 | mthread_cond_wait(&count_threshold_cv, &count_mutex); 80 | printf("watch_count(): thread %ld, count = %d, Condition signal received\n", my_id, count); 81 | } 82 | printf("watch_count(): thread %ld, updating the value of count...\n", my_id); 83 | count += 125; 84 | printf("watch_count(): thread %ld, count now = %d\n", my_id, count); 85 | printf("watch_count(): thread %ld, unlocking mutex\n", my_id); 86 | mthread_mutex_unlock(&count_mutex); 87 | mthread_exit(NULL); 88 | } 89 | 90 | int main(int argc, char *argv[]) 91 | { 92 | int i; 93 | long t1 = 1, t2 = 2, t3 = 3; 94 | mthread_t threads[3]; 95 | 96 | printf("-------------------------------------------\n"); 97 | printf("Thread Condition Variable\n"); 98 | printf("-------------------------------------------\n"); 99 | 100 | /* Initialize library, mutex and condition variable objects */ 101 | mthread_init(); 102 | printf("Thread Library Initialised\n"); 103 | 104 | mthread_mutex_init(&count_mutex); 105 | printf("Mutex Initialised\n"); 106 | 107 | mthread_cond_init(&count_threshold_cv); 108 | printf("Condition Variable Initialised\n"); 109 | 110 | 111 | MCHECK(mthread_create(&threads[0], NULL, watch_count, (void *)t1)); 112 | MCHECK(mthread_create(&threads[1], NULL, inc_count, (void *)t2)); 113 | MCHECK(mthread_create(&threads[2], NULL, inc_count, (void *)t3)); 114 | 115 | /* Wait for all threads to complete */ 116 | for (i = 0; i < NUM_THREADS; i++) { 117 | MCHECK(mthread_join(threads[i], NULL)); 118 | } 119 | 120 | printf("Main(): Waited and joined with %d threads.\n", NUM_THREADS); 121 | printf("Final value of count = %d.\n", count); 122 | 123 | if(count == 145) { 124 | printf("TEST PASSED\n"); 125 | } 126 | else { 127 | printf("TEST FAILED\n"); 128 | } 129 | printf("Exit Testcases - Thread Condition Variable\n"); 130 | return 0; 131 | } -------------------------------------------------------------------------------- /one-one/test/mutex_test.c: -------------------------------------------------------------------------------- 1 | /** 2 | * Example code for using mutexes. This program creates 5 threads 3 | * each of which tries to increment two variables - one shared and one 4 | * individual. To access the shared variable mutexes are used to guarantee 5 | * mutual exclusion and race conditions. Absence of race conditions are checked 6 | * by checking if the sum of inidividual values is same as that of the shared 7 | * variable. 8 | */ 9 | 10 | #define _GNU_SOURCE 11 | #include "mthread.h" 12 | #include 13 | #include 14 | #include 15 | #include 16 | 17 | #define MCHECK(FCALL) \ 18 | { \ 19 | int result; \ 20 | if ((result = (FCALL)) != 0) { \ 21 | fprintf(stderr, "FATAL: %s (%s)", strerror(result), #FCALL); \ 22 | exit(-1); \ 23 | } \ 24 | } 25 | 26 | #define print(str) write(1, str, strlen(str)) 27 | 28 | long long c = 0, c1 = 0, c2 = 0, c3 = 0, c4 = 0, c5 = 0, running = 1; 29 | 30 | mthread_mutex_t lock; 31 | 32 | void *thread1(void *arg) { 33 | while(running == 1) { 34 | mthread_mutex_lock(&lock); 35 | c++; 36 | mthread_mutex_unlock(&lock); 37 | c1++; 38 | } 39 | } 40 | 41 | void *thread2(void *arg) { 42 | while(running == 1) { 43 | mthread_mutex_lock(&lock); 44 | c++; 45 | mthread_mutex_unlock(&lock); 46 | c2++; 47 | } 48 | } 49 | 50 | void *thread3(void *arg) { 51 | while(running == 1) { 52 | mthread_mutex_lock(&lock); 53 | c++; 54 | mthread_mutex_unlock(&lock); 55 | c3++; 56 | } 57 | } 58 | 59 | void *thread4(void *arg) { 60 | while(running == 1) { 61 | mthread_mutex_lock(&lock); 62 | c++; 63 | mthread_mutex_unlock(&lock); 64 | c4++; 65 | } 66 | } 67 | 68 | void *thread5(void *arg) { 69 | while(running == 1) { 70 | mthread_mutex_lock(&lock); 71 | c++; 72 | mthread_mutex_unlock(&lock); 73 | c5++; 74 | } 75 | } 76 | 77 | int main(int argc, char **argv) { 78 | mthread_t th1, th2, th3, th4, th5; 79 | 80 | if(argc != 2) { 81 | fprintf(stdout, "Usage: ./program