60 lines
1.3 KiB
Go
60 lines
1.3 KiB
Go
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// Daemonization interface for Unix platforms (implementation)
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//go:build !windows && !plan9 && !js
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// +build !windows,!plan9,!js
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package daemonize
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import (
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"os"
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"syscall"
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"github.com/rclone/rclone/fs"
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)
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// StartDaemon runs background twin of current process.
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// It executes separate parts of code in child and parent processes.
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// Returns child process pid in the parent or nil in the child.
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// The method looks like a fork but safe for goroutines.
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func StartDaemon(args []string) (*os.Process, error) {
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if fs.IsDaemon() {
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// This process is already daemonized
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return nil, nil
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}
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env := append(os.Environ(), fs.DaemonMarkVar+"="+fs.DaemonMarkChild)
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me, err := os.Executable()
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if err != nil {
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me = os.Args[0]
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}
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null, err := os.Open(os.DevNull)
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if err != nil {
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return nil, err
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}
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files := []*os.File{
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null, // (0) stdin
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null, // (1) stdout
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null, // (2) stderr
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}
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sysAttr := &syscall.SysProcAttr{
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// setsid (https://linux.die.net/man/2/setsid) in the child process will reset
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// its process group id (PGID) to its PID thus detaching it from parent.
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// This would make autofs fail because it detects mounting process by its PGID.
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Setsid: false,
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}
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attr := &os.ProcAttr{
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Env: env,
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Files: files,
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Sys: sysAttr,
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}
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daemon, err := os.StartProcess(me, args, attr)
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if err != nil {
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return nil, err
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}
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return daemon, nil
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}
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