github.com/code-reading/golang@v0.0.0-20220303082512-ba5bc0e589a3/go/src/os/signal/internal/pty/pty.go (about)

     1  // Copyright 2017 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:build (aix || darwin || dragonfly || freebsd || (linux && !android) || netbsd || openbsd) && cgo
     6  // +build aix darwin dragonfly freebsd linux,!android netbsd openbsd
     7  // +build cgo
     8  
     9  // Package pty is a simple pseudo-terminal package for Unix systems,
    10  // implemented by calling C functions via cgo.
    11  // This is only used for testing the os/signal package.
    12  package pty
    13  
    14  /*
    15  #define _XOPEN_SOURCE 600
    16  #include <fcntl.h>
    17  #include <stdlib.h>
    18  #include <unistd.h>
    19  */
    20  import "C"
    21  
    22  import (
    23  	"fmt"
    24  	"os"
    25  	"syscall"
    26  )
    27  
    28  type PtyError struct {
    29  	FuncName    string
    30  	ErrorString string
    31  	Errno       syscall.Errno
    32  }
    33  
    34  func ptyError(name string, err error) *PtyError {
    35  	return &PtyError{name, err.Error(), err.(syscall.Errno)}
    36  }
    37  
    38  func (e *PtyError) Error() string {
    39  	return fmt.Sprintf("%s: %s", e.FuncName, e.ErrorString)
    40  }
    41  
    42  func (e *PtyError) Unwrap() error { return e.Errno }
    43  
    44  // Open returns a control pty and the name of the linked process tty.
    45  func Open() (pty *os.File, processTTY string, err error) {
    46  	m, err := C.posix_openpt(C.O_RDWR)
    47  	if err != nil {
    48  		return nil, "", ptyError("posix_openpt", err)
    49  	}
    50  	if _, err := C.grantpt(m); err != nil {
    51  		C.close(m)
    52  		return nil, "", ptyError("grantpt", err)
    53  	}
    54  	if _, err := C.unlockpt(m); err != nil {
    55  		C.close(m)
    56  		return nil, "", ptyError("unlockpt", err)
    57  	}
    58  	processTTY = C.GoString(C.ptsname(m))
    59  	return os.NewFile(uintptr(m), "pty"), processTTY, nil
    60  }