├── .gitignore ├── .travis.yml ├── LICENSE ├── Makefile ├── README.md ├── circle.yml ├── cmd ├── exec.go ├── init.go ├── init_windows.go ├── net.go └── root.go ├── condition ├── conditionalOnExec.go ├── conditionalOnExec_test.go └── conditionalOnNetworkInterface.go ├── core ├── model.go ├── notify.go ├── notify_darwin.go ├── notify_linux.go ├── run.go └── run_test.go ├── goreleaser.yml ├── main.go └── testfiles ├── fail.sh ├── fail_on_5.cmd └── fail_on_5.sh /.gitignore: -------------------------------------------------------------------------------- 1 | # Compiled Object files, Static and Dynamic libs (Shared Objects) 2 | *.o 3 | *.a 4 | *.so 5 | 6 | # Folders 7 | _obj 8 | _test 9 | 10 | # Architecture specific extensions/prefixes 11 | *.[568vq] 12 | [568vq].out 13 | 14 | *.cgo1.go 15 | *.cgo2.c 16 | _cgo_defun.c 17 | _cgo_gotypes.go 18 | _cgo_export.* 19 | 20 | _testmain.go 21 | 22 | *.exe 23 | *.test 24 | *.prof 25 | killswitch 26 | *.log 27 | cover.out 28 | -------------------------------------------------------------------------------- /.travis.yml: -------------------------------------------------------------------------------- 1 | language: go 2 | sudo: false 3 | go: 4 | - 1.7.5 5 | - 1.8 6 | - tip 7 | os: 8 | - linux 9 | - osx 10 | script: 11 | - go test ./... 12 | - go build 13 | install: 14 | - go get -v ./... 15 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | Apache License 2 | Version 2.0, January 2004 3 | http://www.apache.org/licenses/ 4 | 5 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 6 | 7 | 1. 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The text should be enclosed in the appropriate 184 | comment syntax for the file format. We also recommend that a 185 | file or class name and description of purpose be included on the 186 | same "printed page" as the copyright notice for easier 187 | identification within third-party archives. 188 | 189 | Copyright {yyyy} {name of copyright owner} 190 | 191 | Licensed under the Apache License, Version 2.0 (the "License"); 192 | you may not use this file except in compliance with the License. 193 | You may obtain a copy of the License at 194 | 195 | http://www.apache.org/licenses/LICENSE-2.0 196 | 197 | Unless required by applicable law or agreed to in writing, software 198 | distributed under the License is distributed on an "AS IS" BASIS, 199 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 200 | See the License for the specific language governing permissions and 201 | limitations under the License. 202 | 203 | -------------------------------------------------------------------------------- /Makefile: -------------------------------------------------------------------------------- 1 | build: 2 | go build 3 | 4 | install: 5 | go install 6 | 7 | release: 8 | git tag -a ${version} -m "Release ${version}" 9 | git push --follow-tags 10 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # Application Kill Switch 2 | 3 | 4 | [![GoDoc](https://godoc.org/github.com/bep/killswitch?status.svg)](https://godoc.org/github.com/bep/killswitch) 5 | [![Build Status](https://travis-ci.org/bep/killswitch.svg)](https://travis-ci.org/bep/killswitch) [![Build status](https://ci.appveyor.com/api/projects/status/7mbikfi6sxyq7phh?svg=true)](https://ci.appveyor.com/project/bjornerik/killswitch) 6 | 7 | This is a general-purpose and cross-platform application kill switch written in Go. The main use case is to protect applications running with the VPN when the VPN dies, and still keep general network connectivity. But it's extendable, so a time based kill switch for your develpoment IDE should also be possible: "Sorry, boss. My development environment will not start during Christmas!" 8 | 9 | >"A kill switch, also known as an emergency stop or e-stop, is a safety mechanism used to shut off a device in an emergency situation in which it cannot be shut down in the usual manner. (Wikipedia)" 10 | 11 | ## Install 12 | 13 | **Killswitch** is a Go application. The easiest way to intall it is via `go get`: 14 | 15 | ```bash 16 | go get -v github.com/bep/killswitch 17 | ``` 18 | 19 | This application has been confirmed to work fine on OS X, and Linux, and Windows. Desktop notifications implemented on OS X and Linux. 20 | 21 | ## Is it any good? 22 | 23 | [Yes](https://news.ycombinator.com/item?id=3067434) 24 | 25 | ## Use 26 | 27 | Wrap your sensitive application with a kill switch. 28 | 29 | Provide a path to the program to watch and its arguments (optional), and then a conditional. 30 | 31 | The conditional can be a built-in (see the `net` command) or a heartbeat-script 32 | you can write yourself (see the `exec` command). 33 | 34 | 35 | ``` 36 | -a, --args string The program argument list 37 | -e, --exec string The program to watch 38 | --interval int Interval between checks in seconds (default 5) 39 | ``` 40 | 41 | ## Kill Switches 42 | 43 | ### killswitch net 44 | 45 | Will kill your executable if a given network interface vanishes. 46 | 47 | ``` 48 | killswitch net 49 | ``` 50 | 51 | ``` 52 | -n, --name string The name of the network interface that must be present 53 | ``` 54 | 55 | To get the correct interface name to use with this command, try 56 | 57 | ``` 58 | killswitch net list 59 | ``` 60 | 61 | ## killswitch exec 62 | 63 | Will kill your executable if your provided script exits with an error code. 64 | 65 | The script (typically a shell script on *nix or a cmd- or bat-script on Windows) must exit with a non-0 exit-code 66 | to signal that the application under watch should be killed. 67 | 68 | See /testfiles for example scripts for both *nix and Windows. 69 | 70 | If the script is not present on the PATH, the full path must be provided in name. 71 | 72 | 73 | ``` 74 | killswitch exec 75 | ``` 76 | 77 | ``` 78 | -n, --name string The name of the script to use as heartbeat script. If not on PATH, the full path must be provided. 79 | ``` -------------------------------------------------------------------------------- /circle.yml: -------------------------------------------------------------------------------- 1 | deployment: 2 | tag: 3 | tag: /v[0-9]+(\.[0-9]+)*(-.*)*/ 4 | owner: bep 5 | commands: 6 | - gem install fpm 7 | - curl -sL https://git.io/goreleaser | bash -------------------------------------------------------------------------------- /cmd/exec.go: -------------------------------------------------------------------------------- 1 | // Copyright 2015 Bjørn Erik Pedersen 2 | // 3 | // Licensed under the Apache License, Version 2.0 (the "License"); 4 | // you may not use this file except in compliance with the License. 5 | // You may obtain a copy of the License at 6 | // 7 | // http://www.apache.org/licenses/LICENSE-2.0 8 | // 9 | // Unless required by applicable law or agreed to in writing, software 10 | // distributed under the License is distributed on an "AS IS" BASIS, 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 | // See the License for the specific language governing permissions and 13 | // limitations under the License. 14 | 15 | package cmd 16 | 17 | import ( 18 | "fmt" 19 | "github.com/bep/killswitch/condition" 20 | "github.com/bep/killswitch/core" 21 | "github.com/spf13/cobra" 22 | ) 23 | 24 | var heartbeatScript string 25 | 26 | var execCmd = &cobra.Command{ 27 | Use: "exec", 28 | Short: "Will kill your executable if your provided script exits with an error code", 29 | Long: `Will kill your executable if your provided script exits with an error code 30 | 31 | The script (typically a shell script on *nix or a cmd- or bat-script on Windows) must exit with a non-0 exit-code 32 | to signal that the application under watch should be killed. 33 | 34 | See /testfiles for example scripts for both *nix and Windows. 35 | 36 | If the script is not present on the PATH, the full path must be provided in name. 37 | `, 38 | RunE: func(cmd *cobra.Command, args []string) error { 39 | if len(executable) == 0 { 40 | return userError{"Must provide an executable to watch. Note that this must either in PATH or set as a full path."} 41 | } 42 | fmt.Printf("Starting %s with kill switch script %s ...\n", executable, heartbeatScript) 43 | conditional := condition.NewExecConditional(heartbeatScript) 44 | ctx := &core.Context{Executable: executable, Args: execArgs, Interval: interval} 45 | return core.Run(ctx, conditional) 46 | }, 47 | } 48 | 49 | func init() { 50 | rootCmd.AddCommand(execCmd) 51 | 52 | execCmd.Flags().StringVarP(&heartbeatScript, "name", "n", "", "The name of the script to use as heartbeat script. If not on PATH, the full path must be provided.") 53 | } 54 | -------------------------------------------------------------------------------- /cmd/init.go: -------------------------------------------------------------------------------- 1 | // +build !windows 2 | 3 | // Copyright 2015 Bjørn Erik Pedersen 4 | // 5 | // Licensed under the Apache License, Version 2.0 (the "License"); 6 | // you may not use this file except in compliance with the License. 7 | // You may obtain a copy of the License at 8 | // 9 | // http://www.apache.org/licenses/LICENSE-2.0 10 | // 11 | // Unless required by applicable law or agreed to in writing, software 12 | // distributed under the License is distributed on an "AS IS" BASIS, 13 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 | // See the License for the specific language governing permissions and 15 | // limitations under the License. 16 | 17 | package cmd 18 | 19 | import ( 20 | "io" 21 | "log" 22 | "log/syslog" 23 | "os" 24 | ) 25 | 26 | var logWriter io.Writer 27 | 28 | func init() { 29 | syslogWriter, e := syslog.New(syslog.LOG_NOTICE, "killswitch") 30 | 31 | if e != nil { 32 | logWriter = io.MultiWriter(syslogWriter, os.Stdout) 33 | } else { 34 | logWriter = os.Stdout 35 | } 36 | 37 | log.SetOutput(logWriter) 38 | log.SetPrefix("killswitch") 39 | } 40 | -------------------------------------------------------------------------------- /cmd/init_windows.go: -------------------------------------------------------------------------------- 1 | // Copyright 2015 Bjørn Erik Pedersen 2 | // 3 | // Licensed under the Apache License, Version 2.0 (the "License"); 4 | // you may not use this file except in compliance with the License. 5 | // You may obtain a copy of the License at 6 | // 7 | // http://www.apache.org/licenses/LICENSE-2.0 8 | // 9 | // Unless required by applicable law or agreed to in writing, software 10 | // distributed under the License is distributed on an "AS IS" BASIS, 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 | // See the License for the specific language governing permissions and 13 | // limitations under the License. 14 | 15 | package cmd 16 | 17 | import ( 18 | "io" 19 | "log" 20 | "os" 21 | ) 22 | 23 | var logWriter io.Writer 24 | 25 | func init() { 26 | logWriter = os.Stdout 27 | 28 | log.SetOutput(logWriter) 29 | log.SetPrefix("killswitch") 30 | } 31 | -------------------------------------------------------------------------------- /cmd/net.go: -------------------------------------------------------------------------------- 1 | // Copyright 2015 Bjørn Erik Pedersen 2 | // 3 | // Licensed under the Apache License, Version 2.0 (the "License"); 4 | // you may not use this file except in compliance with the License. 5 | // You may obtain a copy of the License at 6 | // 7 | // http://www.apache.org/licenses/LICENSE-2.0 8 | // 9 | // Unless required by applicable law or agreed to in writing, software 10 | // distributed under the License is distributed on an "AS IS" BASIS, 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 | // See the License for the specific language governing permissions and 13 | // limitations under the License. 14 | 15 | package cmd 16 | 17 | import ( 18 | "fmt" 19 | "github.com/bep/killswitch/condition" 20 | "github.com/bep/killswitch/core" 21 | "github.com/spf13/cobra" 22 | "net" 23 | ) 24 | 25 | var networkInterface string 26 | 27 | var netinterfaceCmd = &cobra.Command{ 28 | Use: "net", 29 | Short: "Will kill your executable if a given network interface vanishes", 30 | 31 | RunE: func(cmd *cobra.Command, args []string) error { 32 | if len(executable) == 0 { 33 | return userError{"Must provide an executable to watch. Note that this must either in PATH or set as a full path."} 34 | } 35 | fmt.Printf("Starting %s with kill switch on interface %s ...\n", executable, heartbeatScript) 36 | conditional := condition.NewNetworkInterfaceConditional(heartbeatScript) 37 | ctx := &core.Context{Executable: executable, Args: execArgs, Interval: interval} 38 | return core.Run(ctx, conditional) 39 | }, 40 | } 41 | 42 | var listInterfacesCmd = &cobra.Command{ 43 | Use: "list", 44 | Short: "List your network interfaces", 45 | 46 | RunE: func(cmd *cobra.Command, args []string) error { 47 | networkInterfaces, err := net.Interfaces() 48 | if err != nil { 49 | return err 50 | } 51 | fmt.Printf("Network interfaces (%d):\n", len(networkInterfaces)) 52 | for i, in := range networkInterfaces { 53 | addrs, _ := in.Addrs() 54 | fmt.Println(i+1, in.Name, addrs) 55 | } 56 | return nil 57 | 58 | }, 59 | } 60 | 61 | func init() { 62 | rootCmd.AddCommand(netinterfaceCmd) 63 | netinterfaceCmd.AddCommand(listInterfacesCmd) 64 | 65 | netinterfaceCmd.Flags().StringVarP(&heartbeatScript, "name", "n", "", "The name of the network interface that must be present") 66 | } 67 | -------------------------------------------------------------------------------- /cmd/root.go: -------------------------------------------------------------------------------- 1 | // Copyright 2015 Bjørn Erik Pedersen 2 | // 3 | // Licensed under the Apache License, Version 2.0 (the "License"); 4 | // you may not use this file except in compliance with the License. 5 | // You may obtain a copy of the License at 6 | // 7 | // http://www.apache.org/licenses/LICENSE-2.0 8 | // 9 | // Unless required by applicable law or agreed to in writing, software 10 | // distributed under the License is distributed on an "AS IS" BASIS, 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 | // See the License for the specific language governing permissions and 13 | // limitations under the License. 14 | 15 | package cmd 16 | 17 | import ( 18 | "github.com/spf13/cobra" 19 | "os" 20 | ) 21 | 22 | type userError struct { 23 | s string 24 | } 25 | 26 | func (u userError) Error() string { 27 | return u.s 28 | } 29 | 30 | var cfgFile string 31 | var executable string 32 | var execArgs string 33 | var interval int 34 | var verbose bool 35 | 36 | var rootCmd = &cobra.Command{ 37 | Use: "killswitch", 38 | Short: "Wrap your sensitive application with a kill switch", 39 | Long: `Wrap your sensitive application with a kill switch. 40 | 41 | Provide a path to the program to watch and its arguments (optional), and then a conditional. 42 | 43 | The conditional can be a built-in (see the net command) or a heartbeat-script 44 | you can write yourself (see the exec command). 45 | `, 46 | } 47 | 48 | // Execute is the main entry. 49 | func Execute() { 50 | 51 | rootCmd.SetOutput(logWriter) 52 | rootCmd.SilenceUsage = true 53 | 54 | if c, err := rootCmd.ExecuteC(); err != nil { 55 | if _, ok := err.(userError); ok { 56 | c.Println("") 57 | c.Println(c.UsageString()) 58 | } 59 | 60 | os.Exit(-1) 61 | } 62 | } 63 | 64 | func init() { 65 | rootCmd.PersistentFlags().StringVarP(&executable, "exec", "e", "", "The program to watch") 66 | rootCmd.PersistentFlags().StringVarP(&execArgs, "args", "a", "", "The program argument list") 67 | rootCmd.PersistentFlags().IntVar(&interval, "interval", 5, "Interval between checks in seconds") 68 | } 69 | -------------------------------------------------------------------------------- /condition/conditionalOnExec.go: -------------------------------------------------------------------------------- 1 | // Copyright 2015 Bjørn Erik Pedersen 2 | // 3 | // Licensed under the Apache License, Version 2.0 (the "License"); 4 | // you may not use this file except in compliance with the License. 5 | // You may obtain a copy of the License at 6 | // 7 | // http://www.apache.org/licenses/LICENSE-2.0 8 | // 9 | // Unless required by applicable law or agreed to in writing, software 10 | // distributed under the License is distributed on an "AS IS" BASIS, 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 | // See the License for the specific language governing permissions and 13 | // limitations under the License. 14 | 15 | package condition 16 | 17 | import ( 18 | "fmt" 19 | "github.com/bep/killswitch/core" 20 | "log" 21 | "os/exec" 22 | "sync/atomic" 23 | ) 24 | 25 | type execConditional struct { 26 | execPath string 27 | 28 | // used in tests 29 | appendCounter bool 30 | opCounter uint64 31 | } 32 | 33 | func (c *execConditional) execAndArgs() (string, []string) { 34 | atomic.AddUint64(&c.opCounter, 1) 35 | if !c.appendCounter { 36 | return c.execPath, []string{} 37 | } 38 | return c.execPath, []string{fmt.Sprintf("%d", c.getOpCounter())} 39 | } 40 | 41 | func (c *execConditional) getOpCounter() uint64 { 42 | return atomic.LoadUint64(&c.opCounter) 43 | } 44 | 45 | func (c *execConditional) Valid(ctx *core.Context) (bool, error) { 46 | 47 | executable, args := c.execAndArgs() 48 | cmd := exec.Command(executable, args...) 49 | 50 | err := cmd.Run() 51 | 52 | if err != nil { 53 | if _, ok := err.(*exec.ExitError); ok { 54 | return false, nil 55 | } 56 | log.Printf("error: Verify Run: %s", err) 57 | return false, err 58 | 59 | } 60 | 61 | return true, nil 62 | } 63 | 64 | // NewExecConditional creates a Conditional that is valid unless the 65 | // executable defined by execPath returns non-zero exit code. 66 | func NewExecConditional(execPath string) core.Conditional { 67 | return &execConditional{execPath: execPath} 68 | } 69 | 70 | func newExecConditionalWithCounter(execPath string) *execConditional { 71 | return &execConditional{execPath: execPath, appendCounter: true} 72 | } 73 | -------------------------------------------------------------------------------- /condition/conditionalOnExec_test.go: -------------------------------------------------------------------------------- 1 | package condition 2 | 3 | import ( 4 | "github.com/bep/killswitch/core" 5 | "os" 6 | "path/filepath" 7 | "runtime" 8 | "sync/atomic" 9 | "testing" 10 | "time" 11 | ) 12 | 13 | func TestConditionalOnExec(t *testing.T) { 14 | 15 | validationScript := "fail_on_5.sh" 16 | testExecutable := "/usr/bin/yes" 17 | 18 | if runtime.GOOS == "windows" { 19 | validationScript = "fail_on_5.cmd" 20 | testExecutable = "notepad.exe" 21 | } 22 | 23 | currDir, _ := os.Getwd() 24 | testFilesDir := filepath.Join(currDir, "..", "testfiles") 25 | testScript := filepath.Join(testFilesDir, validationScript) 26 | 27 | conditional := newExecConditionalWithCounter(testScript) 28 | 29 | ctx := &core.Context{Executable: testExecutable, Interval: 2} 30 | 31 | var finished uint64 32 | 33 | go func() { 34 | err := core.Run(ctx, conditional) 35 | if err != nil { 36 | t.Fatalf("Run() returned err: %s", err) 37 | } 38 | atomic.AddUint64(&finished, 1) 39 | 40 | }() 41 | 42 | time.Sleep(time.Second * 10) 43 | 44 | if !atomic.CompareAndSwapUint64(&finished, 1, 2) { 45 | t.Errorf("Run() did not finish in time") 46 | } else { 47 | if conditional.getOpCounter() != 5 { 48 | t.Errorf("Counter not reached its limit: %d", conditional.getOpCounter()) 49 | 50 | } 51 | } 52 | } 53 | -------------------------------------------------------------------------------- /condition/conditionalOnNetworkInterface.go: -------------------------------------------------------------------------------- 1 | // Copyright 2015 Bjørn Erik Pedersen 2 | // 3 | // Licensed under the Apache License, Version 2.0 (the "License"); 4 | // you may not use this file except in compliance with the License. 5 | // You may obtain a copy of the License at 6 | // 7 | // http://www.apache.org/licenses/LICENSE-2.0 8 | // 9 | // Unless required by applicable law or agreed to in writing, software 10 | // distributed under the License is distributed on an "AS IS" BASIS, 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 | // See the License for the specific language governing permissions and 13 | // limitations under the License. 14 | 15 | package condition 16 | 17 | import ( 18 | "net" 19 | 20 | "github.com/bep/killswitch/core" 21 | ) 22 | 23 | type networkInterfaceConditional struct { 24 | name string 25 | } 26 | 27 | func (n networkInterfaceConditional) Valid(ctx *core.Context) (bool, error) { 28 | networkInterfaces, err := net.Interfaces() 29 | if err != nil { 30 | return false, err 31 | } 32 | 33 | for _, in := range networkInterfaces { 34 | if in.Name == n.name { 35 | return true, nil 36 | } 37 | 38 | } 39 | return false, nil 40 | } 41 | 42 | // NewNetworkInterfaceConditional creates a Conditional that is valid 43 | // as long as the named network interface is present. 44 | func NewNetworkInterfaceConditional(name string) core.Conditional { 45 | return networkInterfaceConditional{name: name} 46 | } 47 | -------------------------------------------------------------------------------- /core/model.go: -------------------------------------------------------------------------------- 1 | // Copyright 2015 Bjørn Erik Pedersen 2 | // 3 | // Licensed under the Apache License, Version 2.0 (the "License"); 4 | // you may not use this file except in compliance with the License. 5 | // You may obtain a copy of the License at 6 | // 7 | // http://www.apache.org/licenses/LICENSE-2.0 8 | // 9 | // Unless required by applicable law or agreed to in writing, software 10 | // distributed under the License is distributed on an "AS IS" BASIS, 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 | // See the License for the specific language governing permissions and 13 | // limitations under the License. 14 | 15 | package core 16 | 17 | // Context defines the program to kill. 18 | type Context struct { 19 | Executable string 20 | Args string 21 | Interval int 22 | } 23 | 24 | // Conditional defines when to kill the program. 25 | type Conditional interface { 26 | Valid(ctx *Context) (bool, error) 27 | } 28 | -------------------------------------------------------------------------------- /core/notify.go: -------------------------------------------------------------------------------- 1 | // +build windows 2 | 3 | // Copyright 2015 Bjørn Erik Pedersen 4 | // 5 | // Licensed under the Apache License, Version 2.0 (the "License"); 6 | // you may not use this file except in compliance with the License. 7 | // You may obtain a copy of the License at 8 | // 9 | // http://www.apache.org/licenses/LICENSE-2.0 10 | // 11 | // Unless required by applicable law or agreed to in writing, software 12 | // distributed under the License is distributed on an "AS IS" BASIS, 13 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 | // See the License for the specific language governing permissions and 15 | // limitations under the License. 16 | 17 | package core 18 | 19 | import ( 20 | "log" 21 | ) 22 | 23 | func notify(title, message string) error { 24 | log.Printf("%s: %s\n", title, message) 25 | return nil 26 | } 27 | -------------------------------------------------------------------------------- /core/notify_darwin.go: -------------------------------------------------------------------------------- 1 | // Copyright 2015 Bjørn Erik Pedersen 2 | // 3 | // Licensed under the Apache License, Version 2.0 (the "License"); 4 | // you may not use this file except in compliance with the License. 5 | // You may obtain a copy of the License at 6 | // 7 | // http://www.apache.org/licenses/LICENSE-2.0 8 | // 9 | // Unless required by applicable law or agreed to in writing, software 10 | // distributed under the License is distributed on an "AS IS" BASIS, 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 | // See the License for the specific language governing permissions and 13 | // limitations under the License. 14 | 15 | package core 16 | 17 | import ( 18 | "fmt" 19 | "log" 20 | "os/exec" 21 | ) 22 | 23 | func notify(title, message string) error { 24 | log.Printf("%s: %s\n", title, message) 25 | s := fmt.Sprintf(`display notification "%s" with title "%s" sound name "Submarine"`, message, title) 26 | cmd := exec.Command("osascript", "-e", s) 27 | return cmd.Run() 28 | } 29 | -------------------------------------------------------------------------------- /core/notify_linux.go: -------------------------------------------------------------------------------- 1 | // +build linux 2 | 3 | // Copyright 2015 Bjørn Erik Pedersen 4 | // 5 | // Licensed under the Apache License, Version 2.0 (the "License"); 6 | // you may not use this file except in compliance with the License. 7 | // You may obtain a copy of the License at 8 | // 9 | // http://www.apache.org/licenses/LICENSE-2.0 10 | // 11 | // Unless required by applicable law or agreed to in writing, software 12 | // distributed under the License is distributed on an "AS IS" BASIS, 13 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 | // See the License for the specific language governing permissions and 15 | // limitations under the License. 16 | 17 | package core 18 | 19 | import ( 20 | "log" 21 | "os/exec" 22 | ) 23 | 24 | var notifySendMissingLogged bool 25 | 26 | func notify(title, message string) error { 27 | log.Printf("%s: %s\n", title, message) 28 | 29 | if !notifySendMissingLogged { 30 | err := exec.Command("notify-send", title, message).Run() 31 | if err != nil { 32 | notifySendMissingLogged = true 33 | log.Println("error: Cannot send notifications on Linux:", err) 34 | } 35 | } 36 | 37 | return nil 38 | } 39 | -------------------------------------------------------------------------------- /core/run.go: -------------------------------------------------------------------------------- 1 | // Copyright 2015 Bjørn Erik Pedersen 2 | // 3 | // Licensed under the Apache License, Version 2.0 (the "License"); 4 | // you may not use this file except in compliance with the License. 5 | // You may obtain a copy of the License at 6 | // 7 | // http://www.apache.org/licenses/LICENSE-2.0 8 | // 9 | // Unless required by applicable law or agreed to in writing, software 10 | // distributed under the License is distributed on an "AS IS" BASIS, 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 | // See the License for the specific language governing permissions and 13 | // limitations under the License. 14 | 15 | package core 16 | 17 | import ( 18 | "fmt" 19 | "log" 20 | "os" 21 | "os/exec" 22 | "path/filepath" 23 | "strings" 24 | "time" 25 | ) 26 | 27 | // Run runs the exectutable defined in ctx and applies the conditionals. 28 | func Run(ctx *Context, conditionals ...Conditional) error { 29 | 30 | // do a prestart check 31 | b, err := checkConditionals(ctx, conditionals...) 32 | 33 | if err != nil { 34 | return err 35 | } 36 | 37 | if !b { 38 | program := filepath.Base(ctx.Executable) 39 | err = notify(fmt.Sprintf("Cannot start %s", program), "Blocked by kill switch!") 40 | 41 | if err != nil { 42 | log.Println("Notify errored:", err) 43 | } 44 | return fmt.Errorf("Conditions evaluated to false before startup of %s", program) 45 | } 46 | 47 | var ( 48 | cmd *exec.Cmd 49 | condStopSignal = make(chan bool, 1) 50 | execEndedSignal = make(chan bool, 1) 51 | ticker *time.Ticker 52 | ) 53 | 54 | cmd = exec.Command(ctx.Executable, strings.Split(ctx.Args, " ")...) 55 | 56 | go func(c *exec.Cmd, stop chan<- bool) { 57 | c.Stdin = os.Stdin 58 | c.Stdout = os.Stdout 59 | c.Stderr = os.Stderr 60 | 61 | err := c.Run() 62 | 63 | if err != nil { 64 | log.Printf("Command.Run: %s", err) 65 | } 66 | 67 | stop <- true 68 | }(cmd, execEndedSignal) 69 | 70 | interval := 5 71 | if ctx.Interval > 0 { 72 | interval = ctx.Interval 73 | } 74 | ticker = time.NewTicker(time.Duration(interval) * time.Second) 75 | 76 | go func(ticker *time.Ticker, stop chan<- bool) { 77 | for { 78 | select { 79 | case <-ticker.C: 80 | b, err := checkConditionals(ctx, conditionals...) 81 | if err != nil { 82 | log.Println("error: Conditionals check returned error:", err) 83 | } 84 | if !b { 85 | stop <- true 86 | return 87 | } 88 | } 89 | 90 | } 91 | }(ticker, condStopSignal) 92 | 93 | for { 94 | select { 95 | case <-condStopSignal: 96 | ticker.Stop() 97 | return killProcess(cmd) 98 | case <-execEndedSignal: 99 | log.Println("Program ended on its own ...") 100 | ticker.Stop() 101 | return nil 102 | } 103 | } 104 | 105 | } 106 | 107 | func killProcess(cmd *exec.Cmd) error { 108 | log.Println("Stopping ...") 109 | 110 | err := cmd.Process.Signal(os.Kill) 111 | if err != nil { 112 | // TODO(bep) try again? Other kill signal? 113 | return err 114 | } 115 | 116 | program := filepath.Base(cmd.Path) 117 | return notify(fmt.Sprintf("Killed %s", program), "Blocked by kill switch!") 118 | 119 | } 120 | 121 | func checkConditionals(ctx *Context, conditionals ...Conditional) (bool, error) { 122 | for _, c := range conditionals { 123 | b, err := c.Valid(ctx) 124 | 125 | if err != nil { 126 | return false, err 127 | } 128 | 129 | if !b { 130 | return false, nil 131 | } 132 | } 133 | 134 | return true, nil 135 | } 136 | -------------------------------------------------------------------------------- /core/run_test.go: -------------------------------------------------------------------------------- 1 | package core 2 | 3 | import ( 4 | "runtime" 5 | "sync/atomic" 6 | "testing" 7 | "time" 8 | ) 9 | 10 | const limit = 4 11 | 12 | func TestRun(t *testing.T) { 13 | 14 | testExecutable := "/usr/bin/yes" 15 | 16 | if runtime.GOOS == "windows" { 17 | testExecutable = "notepad.exe" 18 | } 19 | 20 | ctx := &Context{Executable: testExecutable, Interval: 1} 21 | c := &countingConditional{counter: 0, limit: limit} 22 | var finished uint64 23 | 24 | go func() { 25 | err := Run(ctx, c) 26 | if err != nil { 27 | t.Fatalf("Run() returned err: %s", err) 28 | } 29 | atomic.AddUint64(&finished, 1) 30 | 31 | }() 32 | 33 | time.Sleep(time.Second * limit) 34 | 35 | if !atomic.CompareAndSwapUint64(&finished, 1, 2) { 36 | t.Errorf("Run() did not finish in time") 37 | } else { 38 | if c.counter != limit { 39 | t.Errorf("Counter not reached its limit: %d", c.counter) 40 | 41 | } 42 | } 43 | 44 | } 45 | 46 | type countingConditional struct { 47 | counter int 48 | limit int 49 | } 50 | 51 | func (c *countingConditional) Valid(ctx *Context) (bool, error) { 52 | c.counter++ 53 | return c.counter < c.limit, nil 54 | } 55 | -------------------------------------------------------------------------------- /goreleaser.yml: -------------------------------------------------------------------------------- 1 | build: 2 | main: main.go 3 | binary: killswitch 4 | goos: 5 | - darwin 6 | - linux 7 | - windows 8 | goarch: 9 | - amd64 10 | - 386 11 | - arm 12 | - arm64 13 | fpm: 14 | formats: 15 | - deb 16 | vendor: "bep" 17 | url: "https://github.com/bep/killswitch" 18 | maintainer: "Bjørn Erik Pedersen " 19 | description: "Wrap your sensitive application in a kill switch." 20 | license: "Apache-2.0" 21 | archive: 22 | format: tar.gz 23 | format_overrides: 24 | - goos: windows 25 | format: zip 26 | name_template: "{{.Binary}}_{{.Version}}_{{.Os}}-{{.Arch}}" 27 | replacements: 28 | amd64: 64bit 29 | 386: 32bit 30 | arm: ARM 31 | arm64: ARM64 32 | darwin: macOS 33 | linux: Linux 34 | windows: Windows 35 | files: 36 | - README.md 37 | - LICENSE 38 | -------------------------------------------------------------------------------- /main.go: -------------------------------------------------------------------------------- 1 | // Copyright 2015 Bjørn Erik Pedersen 2 | // 3 | // Licensed under the Apache License, Version 2.0 (the "License"); 4 | // you may not use this file except in compliance with the License. 5 | // You may obtain a copy of the License at 6 | // 7 | // http://www.apache.org/licenses/LICENSE-2.0 8 | // 9 | // Unless required by applicable law or agreed to in writing, software 10 | // distributed under the License is distributed on an "AS IS" BASIS, 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 | // See the License for the specific language governing permissions and 13 | // limitations under the License. 14 | 15 | package main 16 | 17 | import ( 18 | "github.com/bep/killswitch/cmd" 19 | ) 20 | 21 | func main() { 22 | cmd.Execute() 23 | } 24 | -------------------------------------------------------------------------------- /testfiles/fail.sh: -------------------------------------------------------------------------------- 1 | #!/bin/bash 2 | exit -1 3 | -------------------------------------------------------------------------------- /testfiles/fail_on_5.cmd: -------------------------------------------------------------------------------- 1 | @echo off 2 | if %1==5 exit /B 1 3 | -------------------------------------------------------------------------------- /testfiles/fail_on_5.sh: -------------------------------------------------------------------------------- 1 | #!/bin/bash 2 | 3 | if [ "$1" -eq "5" ] 4 | then 5 | echo "Fail on 5" 6 | exit -1 7 | fi 8 | 9 | --------------------------------------------------------------------------------