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// Copyright 2019 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
// This code is heavily inspired by the archived gofacebook/gracenet/net.go handler
//go:build !windows
package graceful
import (
"fmt"
"net"
"os"
"os/exec"
"strconv"
"strings"
"sync"
"syscall"
)
var killParent sync.Once
// KillParent sends the kill signal to the parent process if we are a child
func KillParent() {
killParent.Do(func() {
if GetManager().IsChild() {
ppid := syscall.Getppid()
if ppid > 1 {
_ = syscall.Kill(ppid, syscall.SIGTERM)
}
}
})
}
// RestartProcess starts a new process passing it the active listeners. It
// doesn't fork, but starts a new process using the same environment and
// arguments as when it was originally started. This allows for a newly
// deployed binary to be started. It returns the pid of the newly started
// process when successful.
func RestartProcess() (int, error) {
listeners := getActiveListeners()
// Extract the fds from the listeners.
files := make([]*os.File, len(listeners))
for i, l := range listeners {
var err error
// Now, all our listeners actually have File() functions so instead of
// individually casting we just use a hacky interface
files[i], err = l.(filer).File()
if err != nil {
return 0, err
}
if unixListener, ok := l.(*net.UnixListener); ok {
unixListener.SetUnlinkOnClose(false)
}
// Remember to close these at the end.
defer func(i int) {
_ = files[i].Close()
}(i)
}
// Use the original binary location. This works with symlinks such that if
// the file it points to has been changed we will use the updated symlink.
argv0, err := exec.LookPath(os.Args[0])
if err != nil {
return 0, err
}
// Pass on the environment and replace the old count key with the new one.
var env []string
for _, v := range os.Environ() {
if !strings.HasPrefix(v, listenFDs+"=") {
env = append(env, v)
}
}
env = append(env, fmt.Sprintf("%s=%d", listenFDs, len(listeners)))
sb := &strings.Builder{}
for i, unlink := range getActiveListenersToUnlink() {
if !unlink {
continue
}
_, _ = sb.WriteString(strconv.Itoa(i))
_, _ = sb.WriteString(",")
}
unlinkStr := sb.String()
if len(unlinkStr) > 0 {
unlinkStr = unlinkStr[:len(unlinkStr)-1]
env = append(env, fmt.Sprintf("%s=%s", unlinkFDs, unlinkStr))
}
allFiles := append([]*os.File{os.Stdin, os.Stdout, os.Stderr}, files...)
process, err := os.StartProcess(argv0, os.Args, &os.ProcAttr{
Dir: originalWD,
Env: env,
Files: allFiles,
})
if err != nil {
return 0, err
}
return process.Pid, nil
}
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