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104 lines
3.1 KiB
Go
104 lines
3.1 KiB
Go
package signal // import "github.com/docker/docker/pkg/signal"
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import (
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"fmt"
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"os"
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gosignal "os/signal"
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"path/filepath"
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"runtime"
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"strings"
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"sync/atomic"
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"syscall"
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"time"
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"github.com/pkg/errors"
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)
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// Trap sets up a simplified signal "trap", appropriate for common
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// behavior expected from a vanilla unix command-line tool in general
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// (and the Docker engine in particular).
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//
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// * If SIGINT or SIGTERM are received, `cleanup` is called, then the process is terminated.
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// * If SIGINT or SIGTERM are received 3 times before cleanup is complete, then cleanup is
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// skipped and the process is terminated immediately (allows force quit of stuck daemon)
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// * A SIGQUIT always causes an exit without cleanup, with a goroutine dump preceding exit.
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// * Ignore SIGPIPE events. These are generated by systemd when journald is restarted while
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// the docker daemon is not restarted and also running under systemd.
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// Fixes https://github.com/docker/docker/issues/19728
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//
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func Trap(cleanup func(), logger interface {
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Info(args ...interface{})
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}) {
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c := make(chan os.Signal, 1)
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// we will handle INT, TERM, QUIT, SIGPIPE here
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signals := []os.Signal{os.Interrupt, syscall.SIGTERM, syscall.SIGQUIT, syscall.SIGPIPE}
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gosignal.Notify(c, signals...)
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go func() {
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interruptCount := uint32(0)
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for sig := range c {
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if sig == syscall.SIGPIPE {
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continue
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}
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go func(sig os.Signal) {
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logger.Info(fmt.Sprintf("Processing signal '%v'", sig))
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switch sig {
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case os.Interrupt, syscall.SIGTERM:
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if atomic.LoadUint32(&interruptCount) < 3 {
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// Initiate the cleanup only once
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if atomic.AddUint32(&interruptCount, 1) == 1 {
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// Call the provided cleanup handler
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cleanup()
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os.Exit(0)
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} else {
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return
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}
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} else {
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// 3 SIGTERM/INT signals received; force exit without cleanup
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logger.Info("Forcing docker daemon shutdown without cleanup; 3 interrupts received")
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}
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case syscall.SIGQUIT:
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DumpStacks("")
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logger.Info("Forcing docker daemon shutdown without cleanup on SIGQUIT")
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}
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// for the SIGINT/TERM, and SIGQUIT non-clean shutdown case, exit with 128 + signal #
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os.Exit(128 + int(sig.(syscall.Signal)))
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}(sig)
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}
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}()
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}
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const stacksLogNameTemplate = "goroutine-stacks-%s.log"
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// DumpStacks appends the runtime stack into file in dir and returns full path
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// to that file.
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func DumpStacks(dir string) (string, error) {
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var (
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buf []byte
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stackSize int
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)
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bufferLen := 16384
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for stackSize == len(buf) {
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buf = make([]byte, bufferLen)
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stackSize = runtime.Stack(buf, true)
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bufferLen *= 2
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}
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buf = buf[:stackSize]
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var f *os.File
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if dir != "" {
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path := filepath.Join(dir, fmt.Sprintf(stacksLogNameTemplate, strings.Replace(time.Now().Format(time.RFC3339), ":", "", -1)))
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var err error
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f, err = os.OpenFile(path, os.O_CREATE|os.O_WRONLY, 0666)
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if err != nil {
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return "", errors.Wrap(err, "failed to open file to write the goroutine stacks")
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}
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defer f.Close()
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defer f.Sync()
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} else {
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f = os.Stderr
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}
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if _, err := f.Write(buf); err != nil {
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return "", errors.Wrap(err, "failed to write goroutine stacks")
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}
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return f.Name(), nil
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}
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