110 lines
2.6 KiB
Go
110 lines
2.6 KiB
Go
//go:build !windows && !plan9 && !js
|
|
// +build !windows,!plan9,!js
|
|
|
|
// Package daemonize provides daemonization interface for Unix platforms.
|
|
package daemonize
|
|
|
|
import (
|
|
"os"
|
|
"strings"
|
|
"syscall"
|
|
|
|
"github.com/rclone/rclone/fs"
|
|
)
|
|
|
|
// StartDaemon runs background twin of current process.
|
|
// It executes separate parts of code in child and parent processes.
|
|
// Returns child process pid in the parent or nil in the child.
|
|
// The method looks like a fork but safe for goroutines.
|
|
func StartDaemon(args []string) (*os.Process, error) {
|
|
if fs.IsDaemon() {
|
|
// This process is already daemonized
|
|
return nil, nil
|
|
}
|
|
|
|
env := append(os.Environ(), fs.DaemonMarkVar+"="+fs.DaemonMarkChild)
|
|
|
|
me, err := os.Executable()
|
|
if err != nil {
|
|
me = os.Args[0]
|
|
}
|
|
|
|
// os.Executable might have resolved symbolic link to the executable
|
|
// so we run the background process with pre-converted CLI arguments.
|
|
// Double conversion is still probable but isn't a problem as it should
|
|
// preserve the converted command line.
|
|
if len(args) != 0 {
|
|
args[0] = me
|
|
}
|
|
|
|
if fs.PassDaemonArgsAsEnviron {
|
|
args, env = argsToEnv(args, env)
|
|
}
|
|
|
|
null, err := os.Open(os.DevNull)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
files := []*os.File{
|
|
null, // (0) stdin
|
|
null, // (1) stdout
|
|
null, // (2) stderr
|
|
}
|
|
sysAttr := &syscall.SysProcAttr{
|
|
// setsid (https://linux.die.net/man/2/setsid) in the child process will reset
|
|
// its process group id (PGID) to its PID thus detaching it from parent.
|
|
// This would make autofs fail because it detects mounting process by its PGID.
|
|
Setsid: false,
|
|
}
|
|
attr := &os.ProcAttr{
|
|
Env: env,
|
|
Files: files,
|
|
Sys: sysAttr,
|
|
}
|
|
|
|
daemon, err := os.StartProcess(me, args, attr)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
return daemon, nil
|
|
}
|
|
|
|
// Processed command line flags of mount helper have simple structure:
|
|
// `--flag` or `--flag=value` but never `--flag value` or `-x`
|
|
// so we can easily pass them as environment variables.
|
|
func argsToEnv(origArgs, origEnv []string) (args, env []string) {
|
|
env = origEnv
|
|
if len(origArgs) == 0 {
|
|
return
|
|
}
|
|
args = []string{origArgs[0]}
|
|
for _, arg := range origArgs[1:] {
|
|
if !strings.HasPrefix(arg, "--") {
|
|
args = append(args, arg)
|
|
continue
|
|
}
|
|
|
|
arg = arg[2:]
|
|
key, val := arg, "true"
|
|
if idx := strings.Index(arg, "="); idx != -1 {
|
|
key, val = arg[:idx], arg[idx+1:]
|
|
}
|
|
|
|
name := "RCLONE_" + strings.ToUpper(strings.ReplaceAll(key, "-", "_"))
|
|
|
|
pref := name + "="
|
|
line := name + "=" + val
|
|
found := false
|
|
for i, s := range env {
|
|
if strings.HasPrefix(s, pref) {
|
|
env[i] = line
|
|
found = true
|
|
}
|
|
}
|
|
if !found {
|
|
env = append(env, line)
|
|
}
|
|
}
|
|
return
|
|
}
|