caf5dd9d5e
Before this change we waited until until the timeout to check the
daemon was alive.
Now we check it every 100ms like we do the mount status.
This also fixes compiling on all platforms which was broken by the
previous change
9bfbf2a4a mount: fix macOS not noticing errors with --daemon
See: https://forum.rclone.org/t/rclone-mount-daemon-exits-successfully-even-when-mount-fails/43146
128 lines
3 KiB
Go
128 lines
3 KiB
Go
//go:build unix
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// Package daemonize provides daemonization interface for Unix platforms.
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package daemonize
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import (
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"fmt"
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"os"
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"strings"
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"syscall"
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"github.com/rclone/rclone/fs"
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"golang.org/x/sys/unix"
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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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// os.Executable might have resolved symbolic link to the executable
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// so we run the background process with pre-converted CLI arguments.
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// Double conversion is still probable but isn't a problem as it should
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// preserve the converted command line.
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if len(args) != 0 {
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args[0] = me
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}
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if fs.PassDaemonArgsAsEnviron {
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args, env = argsToEnv(args, env)
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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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// Processed command line flags of mount helper have simple structure:
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// `--flag` or `--flag=value` but never `--flag value` or `-x`
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// so we can easily pass them as environment variables.
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func argsToEnv(origArgs, origEnv []string) (args, env []string) {
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env = origEnv
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if len(origArgs) == 0 {
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return
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}
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args = []string{origArgs[0]}
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for _, arg := range origArgs[1:] {
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if !strings.HasPrefix(arg, "--") {
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args = append(args, arg)
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continue
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}
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arg = arg[2:]
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key, val := arg, "true"
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if idx := strings.Index(arg, "="); idx != -1 {
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key, val = arg[:idx], arg[idx+1:]
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}
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name := "RCLONE_" + strings.ToUpper(strings.ReplaceAll(key, "-", "_"))
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pref := name + "="
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line := name + "=" + val
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found := false
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for i, s := range env {
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if strings.HasPrefix(s, pref) {
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env[i] = line
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found = true
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}
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}
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if !found {
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env = append(env, line)
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}
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}
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return
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}
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// Check returns non nil if the daemon process has died
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func Check(daemon *os.Process) error {
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var status unix.WaitStatus
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wpid, err := unix.Wait4(daemon.Pid, &status, unix.WNOHANG, nil)
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// fs.Debugf(nil, "wait4 returned wpid=%d, err=%v, status=%d", wpid, err, status)
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if err != nil {
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return err
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}
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if wpid == 0 {
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return nil
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}
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if status.Exited() {
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return fmt.Errorf("daemon exited with error code %d", status.ExitStatus())
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}
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return nil
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}
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