1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4  */
5 
6 #include <stdlib.h>
7 #include <unistd.h>
8 #include <errno.h>
9 #include <fcntl.h>
10 #include <kern_util.h>
11 #include <os.h>
12 
13 struct grantpt_info {
14 	int fd;
15 	int res;
16 	int err;
17 };
18 
grantpt_cb(void * arg)19 static void grantpt_cb(void *arg)
20 {
21 	struct grantpt_info *info = arg;
22 
23 	info->res = grantpt(info->fd);
24 	info->err = errno;
25 }
26 
get_pty(void)27 int get_pty(void)
28 {
29 	struct grantpt_info info;
30 	int fd, err;
31 
32 	fd = open("/dev/ptmx", O_RDWR);
33 	if (fd < 0) {
34 		err = -errno;
35 		printk(UM_KERN_ERR "get_pty : Couldn't open /dev/ptmx - "
36 		       "err = %d\n", errno);
37 		return err;
38 	}
39 
40 	info.fd = fd;
41 	initial_thread_cb(grantpt_cb, &info);
42 
43 	if (info.res < 0) {
44 		err = -info.err;
45 		printk(UM_KERN_ERR "get_pty : Couldn't grant pty - "
46 		       "errno = %d\n", -info.err);
47 		goto out;
48 	}
49 
50 	if (unlockpt(fd) < 0) {
51 		err = -errno;
52 		printk(UM_KERN_ERR "get_pty : Couldn't unlock pty - "
53 		       "errno = %d\n", errno);
54 		goto out;
55 	}
56 	return fd;
57 out:
58 	close(fd);
59 	return err;
60 }
61