├── .editorconfig ├── .github ├── FUNDING.yml └── workflows │ └── build.yaml ├── .gitignore ├── CHANGELOG.md ├── Cargo.toml ├── LICENSE-Apache ├── LICENSE-MIT ├── rustfmt.toml ├── src ├── aix.rs ├── apple.rs ├── freebsd.rs ├── imp.rs ├── lib.rs └── linux.rs └── tests.rs /.editorconfig: -------------------------------------------------------------------------------- 1 | root = true 2 | 3 | [*] 4 | indent_style = space 5 | indent_size = 4 6 | end_of_line = lf 7 | charset = utf-8 8 | trim_trailing_whitespace = true 9 | insert_final_newline = true 10 | 11 | [*.yaml] 12 | indent_size = 2 13 | -------------------------------------------------------------------------------- /.github/FUNDING.yml: -------------------------------------------------------------------------------- 1 | github: jhpratt 2 | patreon: jhpratt 3 | custom: ["paypal.me/jhpratt"] 4 | -------------------------------------------------------------------------------- /.github/workflows/build.yaml: -------------------------------------------------------------------------------- 1 | name: Build 2 | 3 | concurrency: 4 | group: build-${{ github.head_ref }} 5 | cancel-in-progress: true 6 | 7 | env: 8 | CARGO_INCREMENTAL: 0 9 | 10 | on: 11 | push: 12 | branches: ["**"] 13 | tags-ignore: ["**"] 14 | paths-ignore: 15 | - "**.md" 16 | - LICENSE-Apache 17 | - LICENSE-MIT 18 | pull_request: 19 | paths-ignore: 20 | - "**.md" 21 | - "**/LICENSE-Apache" 22 | - "**/LICENSE-MIT" 23 | - .github/FUNDING.yml 24 | - .editorconfig 25 | - .gitignore 26 | 27 | jobs: 28 | check: 29 | name: Type checking (${{ matrix.target.name }}) 30 | runs-on: ${{ matrix.target.host }} 31 | if: ${{ (github.event_name == 'pull_request' && github.event.pull_request.head.repo.fork) || github.event_name == 'push' }} 32 | strategy: 33 | matrix: 34 | target: 35 | # name: Windows 36 | # triple: x86_64-pc-windows-gnu 37 | - name: Linux 38 | triple: x86_64-unknown-linux-gnu 39 | host: ubuntu-latest 40 | - name: Android 41 | triple: aarch64-linux-android 42 | host: ubuntu-latest 43 | - name: macOS 44 | triple: x86_64-apple-darwin 45 | host: macos-latest 46 | - name: iOS 47 | triple: aarch64-apple-ios 48 | host: macos-latest 49 | - name: FreeBSD 50 | triple: x86_64-unknown-freebsd 51 | host: ubuntu-latest 52 | 53 | steps: 54 | - name: Checkout sources 55 | uses: actions/checkout@v2 56 | 57 | - name: Install toolchain 58 | uses: actions-rs/toolchain@v1 59 | with: 60 | profile: minimal 61 | toolchain: 1.54.0 62 | target: ${{ matrix.target.triple }} 63 | override: true 64 | 65 | - name: Cache cargo output 66 | uses: Swatinem/rust-cache@v1 67 | with: 68 | key: ${{ matrix.target.triple }} 69 | 70 | - name: Type checking 71 | uses: actions-rs/cargo@v1 72 | with: 73 | command: check 74 | args: --target ${{ matrix.target.triple }} 75 | 76 | test: 77 | name: Test (${{ matrix.target.name}}) 78 | runs-on: ${{ matrix.target.host }} 79 | if: ${{ (github.event_name == 'pull_request' && github.event.pull_request.head.repo.fork) || github.event_name == 'push' }} 80 | strategy: 81 | matrix: 82 | target: 83 | # name: Windows 84 | # host: windows-latest 85 | # triple: x86_64-pc-windows-gnu 86 | - name: Linux 87 | host: ubuntu-latest 88 | triple: x86_64-unknown-linux-gnu 89 | - name: macOS 90 | host: macos-latest 91 | triple: x86_64-apple-darwin 92 | 93 | steps: 94 | - name: Checkout sources 95 | uses: actions/checkout@v2 96 | 97 | - name: Install toolchain 98 | uses: actions-rs/toolchain@v1 99 | with: 100 | profile: minimal 101 | toolchain: stable 102 | target: ${{ matrix.target.triple }} 103 | override: true 104 | 105 | - name: Cache cargo output 106 | uses: Swatinem/rust-cache@v1 107 | with: 108 | key: ${{ matrix.target.triple }} 109 | 110 | - name: Test 111 | uses: actions-rs/cargo@v1 112 | with: 113 | command: test 114 | args: -- --test-threads=1 115 | 116 | fmt: 117 | name: Formatting 118 | runs-on: ubuntu-20.04 119 | if: ${{ (github.event_name == 'pull_request' && github.event.pull_request.head.repo.fork) || github.event_name == 'push' }} 120 | 121 | steps: 122 | - name: Checkout sources 123 | uses: actions/checkout@v2 124 | 125 | - name: Install toolchain 126 | uses: actions-rs/toolchain@v1 127 | with: 128 | profile: minimal 129 | toolchain: nightly 130 | override: true 131 | components: rustfmt 132 | 133 | - name: Check formatting 134 | uses: actions-rs/cargo@v1 135 | with: 136 | command: fmt 137 | args: -- --check 138 | 139 | clippy: 140 | name: Clippy 141 | runs-on: ubuntu-20.04 142 | if: ${{ (github.event_name == 'pull_request' && github.event.pull_request.head.repo.fork) || github.event_name == 'push' }} 143 | 144 | steps: 145 | - name: Checkout sources 146 | uses: actions/checkout@v2 147 | 148 | - name: Install toolchain 149 | uses: actions-rs/toolchain@v1 150 | with: 151 | profile: minimal 152 | toolchain: stable 153 | override: true 154 | 155 | - name: Cache cargo output 156 | uses: Swatinem/rust-cache@v1 157 | 158 | - name: Run clippy 159 | uses: actions-rs/clippy-check@v1 160 | with: 161 | token: ${{ secrets.GITHUB_TOKEN }} 162 | -------------------------------------------------------------------------------- /.gitignore: -------------------------------------------------------------------------------- 1 | /target 2 | Cargo.lock 3 | -------------------------------------------------------------------------------- /CHANGELOG.md: -------------------------------------------------------------------------------- 1 | # 0.1.7 2 | 3 | Fix memory leak on Apple platforms 4 | 5 | # 0.1.6 6 | 7 | - Avoid heap allocation on FreeBSD 8 | 9 | # 0.1.5 10 | 11 | - Add support for Android and iOS 12 | 13 | # 0.1.4 14 | 15 | - Modified MacOS implementation to be friendly towards Apple app store review guidelines. 16 | 17 | # 0.1.3 18 | 19 | - Avoid heap allocation on MacOS. 20 | 21 | # 0.1.2 22 | 23 | - Add support for MacOS 24 | 25 | # 0.1.1 26 | 27 | - Fix memory leak on FreeBSD 28 | - Improve performance on Linux 29 | 30 | # 0.1.0 31 | 32 | - Initial release with support for Linux, FreeBSD 33 | -------------------------------------------------------------------------------- /Cargo.toml: -------------------------------------------------------------------------------- 1 | [package] 2 | name = "num_threads" 3 | version = "0.1.7" 4 | authors = ["Jacob Pratt "] 5 | repository = "https://github.com/jhpratt/num_threads" 6 | categories = ["api-bindings", "hardware-support", "os"] 7 | license = "MIT OR Apache-2.0" 8 | description = "A minimal library that determines the number of running threads for the current process." 9 | include = ["src/**/*", "LICENSE-*"] 10 | 11 | [package.metadata.docs.rs] 12 | all-features = true 13 | targets = ["x86_64-unknown-linux-gnu"] 14 | 15 | [dependencies] 16 | 17 | [target.'cfg(any(target_os = "macos", target_os = "ios", target_os = "freebsd"))'.dependencies] 18 | libc = "0.2.107" 19 | 20 | [[test]] 21 | name = "tests" 22 | path = "tests.rs" 23 | harness = false 24 | -------------------------------------------------------------------------------- /LICENSE-Apache: -------------------------------------------------------------------------------- 1 | 2 | Apache License 3 | Version 2.0, January 2004 4 | http://www.apache.org/licenses/ 5 | 6 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 7 | 8 | 1. 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We also recommend that a 186 | file or class name and description of purpose be included on the 187 | same "printed page" as the copyright notice for easier 188 | identification within third-party archives. 189 | 190 | Copyright 2021 Jacob Pratt 191 | 192 | Licensed under the Apache License, Version 2.0 (the "License"); 193 | you may not use this file except in compliance with the License. 194 | You may obtain a copy of the License at 195 | 196 | http://www.apache.org/licenses/LICENSE-2.0 197 | 198 | Unless required by applicable law or agreed to in writing, software 199 | distributed under the License is distributed on an "AS IS" BASIS, 200 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 201 | See the License for the specific language governing permissions and 202 | limitations under the License. 203 | -------------------------------------------------------------------------------- /LICENSE-MIT: -------------------------------------------------------------------------------- 1 | Copyright (c) 2021 Jacob Pratt 2 | 3 | Permission is hereby granted, free of charge, to any person obtaining a copy 4 | of this software and associated documentation files (the "Software"), to deal 5 | in the Software without restriction, including without limitation the rights 6 | to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 7 | copies of the Software, and to permit persons to whom the Software is 8 | furnished to do so, subject to the following conditions: 9 | 10 | The above copyright notice and this permission notice shall be included in all 11 | copies or substantial portions of the Software. 12 | 13 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 14 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 15 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 16 | AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 17 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 18 | OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 19 | SOFTWARE. 20 | -------------------------------------------------------------------------------- /rustfmt.toml: -------------------------------------------------------------------------------- 1 | newline_style = "unix" 2 | use_field_init_shorthand = true 3 | use_try_shorthand = true 4 | 5 | # Unstable features below 6 | unstable_features = true 7 | version = "Two" 8 | comment_width = 100 9 | error_on_line_overflow = true 10 | format_code_in_doc_comments = true 11 | format_macro_bodies = true 12 | format_macro_matchers = true 13 | format_strings = true 14 | imports_granularity = "Module" 15 | group_imports = "StdExternalCrate" 16 | normalize_doc_attributes = true 17 | wrap_comments = true 18 | -------------------------------------------------------------------------------- /src/aix.rs: -------------------------------------------------------------------------------- 1 | use std::convert::TryFrom; 2 | use std::fs::File; 3 | use std::io::{BufReader, Read, Seek, SeekFrom}; 4 | use std::num::NonZeroUsize; 5 | 6 | // https://www.ibm.com/docs/en/aix/7.3?topic=files-proc-file 7 | // 8 | // The 'status' file is defined as binary format below 9 | // uint32_t pr_flag; /* process flags from proc struct p_flag */ 10 | // uint32_t pr_flag2; /* process flags from proc struct p_flag2 */ 11 | // uint32_t pr_flags; /* /proc flags */ 12 | // uint32_t pr_nlwp; /* number of threads in the process */ 13 | // ... /* Omitted */ 14 | pub(crate) fn num_threads() -> Option { 15 | let pid = std::process::id(); 16 | let mut file = File::open(format!("/proc/{}/status", pid)).ok()?; 17 | let mut buffer: [u8; 16] = [0; 16]; 18 | // Read 4 bytes after initial 12 bytes and convert into 32-byte uint. 19 | file.read_exact(&mut buffer).ok()?; 20 | let nlwp_bytes = <[u8; 4]>::try_from(&buffer[12..16]).ok()?; 21 | let nlwp = unsafe { std::mem::transmute::<[u8; 4], u32>(nlwp_bytes) }; 22 | NonZeroUsize::new(nlwp as usize) 23 | } 24 | -------------------------------------------------------------------------------- /src/apple.rs: -------------------------------------------------------------------------------- 1 | extern crate libc; 2 | 3 | use std::num::NonZeroUsize; 4 | 5 | use self::libc::{ 6 | kern_return_t, mach_port_t, natural_t, task_threads, thread_act_array_t, vm_size_t, 7 | }; 8 | 9 | #[allow(non_camel_case_types)] 10 | // https://developer.apple.com/documentation/kernel/mach_port_name_t 11 | type mach_port_name_t = natural_t; 12 | 13 | extern "C" { 14 | // https://developer.apple.com/documentation/kernel/1402285-mach_vm_deallocate 15 | fn mach_vm_deallocate( 16 | target_task: mach_port_t, 17 | address: *mut u32, 18 | size: vm_size_t, 19 | ) -> kern_return_t; 20 | 21 | // https://developer.apple.com/documentation/kernel/1578777-mach_port_deallocate 22 | fn mach_port_deallocate(task: mach_port_t, name: mach_port_name_t) -> kern_return_t; 23 | } 24 | 25 | pub(crate) fn num_threads() -> Option { 26 | // https://developer.apple.com/documentation/kernel/1537751-task_threads 27 | let mut thread_list: thread_act_array_t = std::ptr::null_mut(); 28 | let mut thread_count = 0; 29 | 30 | // Safety: 31 | // - `mach_task_self` always returns a valid value, 32 | // - `thread_list` is a pointer that will point to kernel allocated memory that needs to be 33 | // deallocated if the call succeeds 34 | let task = unsafe { libc::mach_task_self() }; 35 | let result = unsafe { task_threads(task, &mut thread_list, &mut thread_count) }; 36 | 37 | if result == libc::KERN_SUCCESS { 38 | // Deallocate the mach port rights for the threads 39 | for thread in 0..thread_count { 40 | unsafe { 41 | mach_port_deallocate(task, *(thread_list.offset(thread as isize)) as u32); 42 | } 43 | } 44 | // Deallocate the thread list 45 | unsafe { 46 | mach_vm_deallocate( 47 | task, 48 | thread_list, 49 | std::mem::size_of::() * thread_count as usize, 50 | ); 51 | } 52 | 53 | NonZeroUsize::new(thread_count as usize) 54 | } else { 55 | None 56 | } 57 | } 58 | -------------------------------------------------------------------------------- /src/freebsd.rs: -------------------------------------------------------------------------------- 1 | extern crate libc; 2 | 3 | use std::num::NonZeroUsize; 4 | use std::{mem, ptr}; 5 | 6 | pub(crate) fn num_threads() -> Option { 7 | // Safety: `sysctl` and `getpid` are both thread-safe. 8 | // `kip` is only accessed if sysctl() succeeds and agrees with the expected size, 9 | // and the data only trusted if both its embedded size and pid match expectations 10 | unsafe { 11 | let pid = libc::getpid(); 12 | let mib: [libc::c_int; 4] = [libc::CTL_KERN, libc::KERN_PROC, libc::KERN_PROC_PID, pid]; 13 | let mut kip: libc::kinfo_proc = mem::zeroed(); 14 | let expected_kip_len = mem::size_of_val(&kip); 15 | let mut kip_len = expected_kip_len; 16 | 17 | let ret = libc::sysctl( 18 | mib.as_ptr(), 19 | mib.len() as u32, 20 | &mut kip as *mut _ as *mut libc::c_void, 21 | &mut kip_len, 22 | ptr::null(), 23 | 0, 24 | ); 25 | 26 | if ret == 0 27 | && kip_len == expected_kip_len 28 | && kip.ki_structsize == expected_kip_len as i32 29 | && kip.ki_pid == pid 30 | { 31 | NonZeroUsize::new(kip.ki_numthreads as usize) 32 | } else { 33 | None 34 | } 35 | } 36 | } 37 | -------------------------------------------------------------------------------- /src/imp.rs: -------------------------------------------------------------------------------- 1 | //! Fallback if no OS matches. 2 | 3 | use std::num::NonZeroUsize; 4 | 5 | pub(crate) fn num_threads() -> Option { 6 | None 7 | } 8 | -------------------------------------------------------------------------------- /src/lib.rs: -------------------------------------------------------------------------------- 1 | //! Minimum supported Rust version: 1.28 2 | 3 | use std::num::NonZeroUsize; 4 | 5 | #[cfg_attr(any(target_os = "linux", target_os = "android"), path = "linux.rs")] 6 | #[cfg_attr(target_os = "freebsd", path = "freebsd.rs")] 7 | #[cfg_attr(any(target_os = "macos", target_os = "ios"), path = "apple.rs")] 8 | #[cfg_attr(target_os = "aix", path = "aix.rs")] 9 | mod imp; 10 | 11 | /// Obtain the number of threads currently part of the active process. Returns `None` if the number 12 | /// of threads cannot be determined. 13 | pub fn num_threads() -> Option { 14 | imp::num_threads() 15 | } 16 | 17 | /// Determine if the current process is single-threaded. Returns `None` if the number of threads 18 | /// cannot be determined. 19 | pub fn is_single_threaded() -> Option { 20 | num_threads().map(|n| n.get() == 1) 21 | } 22 | -------------------------------------------------------------------------------- /src/linux.rs: -------------------------------------------------------------------------------- 1 | use std::fs; 2 | use std::num::NonZeroUsize; 3 | 4 | pub(crate) fn num_threads() -> Option { 5 | fs::read_to_string("/proc/self/stat") 6 | .ok() 7 | .as_ref() 8 | // Skip past the pid and (process name) fields 9 | .and_then(|stat| stat.rsplit(')').next()) 10 | // 20th field, less the two we skipped 11 | .and_then(|rstat| rstat.split_whitespace().nth(17)) 12 | .and_then(|num_threads| num_threads.parse::().ok()) 13 | .and_then(NonZeroUsize::new) 14 | } 15 | -------------------------------------------------------------------------------- /tests.rs: -------------------------------------------------------------------------------- 1 | extern crate num_threads; 2 | 3 | use std::num::NonZeroUsize; 4 | 5 | use num_threads::*; 6 | 7 | // Run each expression in its own thread. 8 | macro_rules! threaded { 9 | ($first:expr;) => { 10 | $first; 11 | }; 12 | ($first:expr; $($rest:expr;)*) => { 13 | $first; 14 | ::std::thread::spawn(|| { 15 | threaded!($($rest;)*); 16 | }) 17 | .join() 18 | .unwrap(); 19 | }; 20 | } 21 | 22 | fn test_single_threaded_by_default() { 23 | if is_single_threaded() != Some(true) { 24 | panic!("Process is not single-threaded, but it should be."); 25 | } 26 | } 27 | 28 | fn test_num_threads() { 29 | threaded! { 30 | assert_eq!(num_threads().map(NonZeroUsize::get), Some(1)); 31 | assert_eq!(num_threads().map(NonZeroUsize::get), Some(2)); 32 | assert_eq!(num_threads().map(NonZeroUsize::get), Some(3)); 33 | assert_eq!(num_threads().map(NonZeroUsize::get), Some(4)); 34 | assert_eq!(num_threads().map(NonZeroUsize::get), Some(5)); 35 | assert_eq!(num_threads().map(NonZeroUsize::get), Some(6)); 36 | } 37 | } 38 | 39 | fn test_is_single_threaded() { 40 | threaded! { 41 | assert_eq!(is_single_threaded(), Some(true)); 42 | assert_eq!(is_single_threaded(), Some(false)); 43 | assert_eq!(is_single_threaded(), Some(false)); 44 | assert_eq!(is_single_threaded(), Some(false)); 45 | assert_eq!(is_single_threaded(), Some(false)); 46 | assert_eq!(is_single_threaded(), Some(false)); 47 | } 48 | } 49 | 50 | fn main() { 51 | test_single_threaded_by_default(); 52 | std::thread::sleep(std::time::Duration::new(0, 100)); 53 | test_num_threads(); 54 | std::thread::sleep(std::time::Duration::new(0, 100)); 55 | test_is_single_threaded(); 56 | eprintln!("All tests passed!"); 57 | } 58 | --------------------------------------------------------------------------------