// +build darwin dragonfly freebsd linux netbsd openbsd plan9 solaris package daemon import ( "encoding/json" "fmt" "os" "syscall" "github.com/kardianos/osext" ) func (d *Context) reborn() (child *os.Process, err error) { if !WasReborn() { child, err = d.parent() } else { err = d.child() } return } func (d *Context) search() (daemon *os.Process, err error) { if len(d.PidFileName) > 0 { var pid int if pid, err = ReadPidFile(d.PidFileName); err != nil { return } daemon, err = os.FindProcess(pid) } return } func (d *Context) parent() (child *os.Process, err error) { if err = d.prepareEnv(); err != nil { return } defer d.closeFiles() if err = d.openFiles(); err != nil { return } attr := &os.ProcAttr{ Dir: d.WorkDir, Env: d.Env, Files: d.files(), Sys: &syscall.SysProcAttr{ //Chroot: d.Chroot, Credential: d.Credential, Setsid: true, }, } if child, err = os.StartProcess(d.abspath, d.Args, attr); err != nil { if d.pidFile != nil { d.pidFile.Remove() } return } d.rpipe.Close() encoder := json.NewEncoder(d.wpipe) err = encoder.Encode(d) return } func (d *Context) openFiles() (err error) { if d.PidFilePerm == 0 { d.PidFilePerm = FILE_PERM } if d.LogFilePerm == 0 { d.LogFilePerm = FILE_PERM } if d.nullFile, err = os.Open(os.DevNull); err != nil { return } if len(d.PidFileName) > 0 { if d.pidFile, err = OpenLockFile(d.PidFileName, d.PidFilePerm); err != nil { return } if err = d.pidFile.Lock(); err != nil { return } } if len(d.LogFileName) > 0 { if d.logFile, err = os.OpenFile(d.LogFileName, os.O_WRONLY|os.O_CREATE|os.O_APPEND, d.LogFilePerm); err != nil { return } } d.rpipe, d.wpipe, err = os.Pipe() return } func (d *Context) closeFiles() (err error) { cl := func(file **os.File) { if *file != nil { (*file).Close() *file = nil } } cl(&d.rpipe) cl(&d.wpipe) cl(&d.logFile) cl(&d.nullFile) if d.pidFile != nil { d.pidFile.Close() d.pidFile = nil } return } func (d *Context) prepareEnv() (err error) { if d.abspath, err = osext.Executable(); err != nil { return } if len(d.Args) == 0 { d.Args = os.Args } mark := fmt.Sprintf("%s=%s", MARK_NAME, MARK_VALUE) if len(d.Env) == 0 { d.Env = os.Environ() } d.Env = append(d.Env, mark) return } func (d *Context) files() (f []*os.File) { log := d.nullFile if d.logFile != nil { log = d.logFile } f = []*os.File{ d.rpipe, // (0) stdin log, // (1) stdout log, // (2) stderr d.nullFile, // (3) dup on fd 0 after initialization } if d.pidFile != nil { f = append(f, d.pidFile.File) // (4) pid file } return } var initialized = false func (d *Context) child() (err error) { if initialized { return os.ErrInvalid } initialized = true if len(d.PidFileName) > 0 { d.pidFile = NewLockFile(os.NewFile(4, d.PidFileName)) if err = d.pidFile.WritePid(); err != nil { return } } decoder := json.NewDecoder(os.Stdin) if err = decoder.Decode(d); err != nil { d.pidFile.Remove() return } if err = syscall.Close(0); err != nil { d.pidFile.Remove() return } if err = syscallDup(3, 0); err != nil { d.pidFile.Remove() return } if d.Umask != 0 { syscall.Umask(int(d.Umask)) } if len(d.Chroot) > 0 { err = syscall.Chroot(d.Chroot) if err != nil { d.pidFile.Remove() return } } return } func (d *Context) release() (err error) { if !initialized { return } if d.pidFile != nil { err = d.pidFile.Remove() } return }