func unlockpt(fd uintptr) error {
rc := C.unlockpt(C.int(fd))
if rc == 0 {
return nil
} else {
return syscall.Errno(rc)
}
}
func (server *Server) Start(
command *StartCommand,
result *StartResult) error {
// We need at least a command.
if len(command.Command) == 0 {
return syscall.EINVAL
}
// Lookup our binary name.
var binary string
_, err := os.Stat(command.Command[0])
if err == nil {
// Absolute path is okay.
binary = command.Command[0]
} else {
// Check our environment.
for _, keyval := range command.Environment {
if strings.HasPrefix(keyval, "PATH=") && len(keyval) > 5 {
dirpaths := strings.Split(keyval[5:], ":")
for _, dirpath := range dirpaths {
testpath := path.Join(dirpath, command.Command[0])
_, err = os.Stat(testpath)
if err == nil {
binary = testpath
break
}
}
}
}
}
// Did we find a binary?
if binary == "" {
return syscall.ENOENT
}
var input *os.File
var output *os.File
var stdin *os.File
var stdout *os.File
var stderr *os.File
if command.Terminal {
// Open a master terminal Fd.
fd, err := C.posix_openpt(syscall.O_RDWR | syscall.O_NOCTTY)
if fd == C.int(-1) && err != nil {
// Out of FDs?
result.Pid = -1
return err
}
// Save our master.
master := os.NewFile(uintptr(fd), "ptmx")
// Try to grant and unlock the PT.
r, err := C.grantpt(C.int(master.Fd()))
if r != C.int(0) && err != nil {
master.Close()
result.Pid = -1
return err
}
r, err = C.unlockpt(C.int(master.Fd()))
if r != C.int(0) && err != nil {
master.Close()
result.Pid = -1
return err
}
// Get the terminal name.
buf := make([]byte, 1024, 1024)
r, err = C.ptsname_r(
C.int(master.Fd()),
(*C.char)(unsafe.Pointer(&buf[0])),
1024)
if r != C.int(0) && err != nil {
master.Close()
result.Pid = -1
return err
}
// Open the slave terminal.
n := bytes.Index(buf, []byte{0})
slave_pts := string(buf[:n])
slave, err := os.OpenFile(slave_pts, syscall.O_RDWR|syscall.O_NOCTTY, 0)
if err != nil {
master.Close()
result.Pid = -1
return err
}
defer slave.Close()
// Set our inputs.
input = master
output = master
stdin = slave
stdout = slave
stderr = slave
} else {
// Allocate pipes.
r1, w1, err := os.Pipe()
if err != nil {
result.Pid = -1
return err
}
r2, w2, err := os.Pipe()
if err != nil {
r1.Close()
w1.Close()
result.Pid = -1
return err
}
defer r1.Close()
defer w2.Close()
// Set our inputs.
input = w1
output = r2
stdin = r1
stdout = w2
stderr = w2
}
// Start the process.
proc_attr := &os.ProcAttr{
Dir: command.Cwd,
Env: command.Environment,
Files: []*os.File{stdin, stdout, stderr},
Sys: &syscall.SysProcAttr{
Setsid: true,
Setctty: command.Terminal,
Ctty: 0,
},
}
proc, err := os.StartProcess(
binary,
command.Command,
proc_attr)
// Unable to start?
if err != nil {
input.Close()
if input != output {
output.Close()
}
result.Pid = -1
return err
}
// Create our process.
process := &Process{
input: input,
output: output,
starttime: time.Now(),
cond: sync.NewCond(&sync.Mutex{}),
}
// Save the pid.
result.Pid = proc.Pid
server.mutex.Lock()
old_process := server.active[result.Pid]
server.active[result.Pid] = process
server.mutex.Unlock()
if old_process != nil {
old_process.close()
}
go server.wait()
return nil
}