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moby--moby/cmd/docker/daemon_unix.go
Daniel Nephin 2777f884f6 Support running 'docker help daemon'
Signed-off-by: Daniel Nephin <dnephin@docker.com>
2016-06-09 13:22:03 -04:00

56 lines
1.4 KiB
Go

// +build daemon
package main
import (
"os"
"os/exec"
"path/filepath"
"syscall"
)
// CmdDaemon execs dockerd with the same flags
func (p DaemonProxy) CmdDaemon(args ...string) error {
// Special case for handling `docker help daemon`. When pkg/mflag is removed
// we can support this on the daemon side, but that is not possible with
// pkg/mflag because it uses os.Exit(1) instead of returning an error on
// unexpected args.
if len(args) == 0 || args[0] != "--help" {
// Use os.Args[1:] so that "global" args are passed to dockerd
args = stripDaemonArg(os.Args[1:])
}
binaryPath, err := findDaemonBinary()
if err != nil {
return err
}
return syscall.Exec(
binaryPath,
append([]string{daemonBinary}, args...),
os.Environ())
}
// findDaemonBinary looks for the path to the dockerd binary starting with
// the directory of the current executable (if one exists) and followed by $PATH
func findDaemonBinary() (string, error) {
execDirname := filepath.Dir(os.Args[0])
if execDirname != "" {
binaryPath := filepath.Join(execDirname, daemonBinary)
if _, err := os.Stat(binaryPath); err == nil {
return binaryPath, nil
}
}
return exec.LookPath(daemonBinary)
}
// stripDaemonArg removes the `daemon` argument from the list
func stripDaemonArg(args []string) []string {
for i, arg := range args {
if arg == "daemon" {
return append(args[:i], args[i+1:]...)
}
}
return args
}