xref: /openbmc/linux/arch/um/os-Linux/tty.c (revision 22246614)
1 /*
2  * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3  * Licensed under the GPL
4  */
5 
6 #include <stdlib.h>
7 #include <unistd.h>
8 #include <errno.h>
9 #include <fcntl.h>
10 #include "kern_constants.h"
11 #include "kern_util.h"
12 #include "os.h"
13 #include "user.h"
14 
15 struct grantpt_info {
16 	int fd;
17 	int res;
18 	int err;
19 };
20 
21 static void grantpt_cb(void *arg)
22 {
23 	struct grantpt_info *info = arg;
24 
25 	info->res = grantpt(info->fd);
26 	info->err = errno;
27 }
28 
29 int get_pty(void)
30 {
31 	struct grantpt_info info;
32 	int fd, err;
33 
34 	fd = open("/dev/ptmx", O_RDWR);
35 	if (fd < 0) {
36 		err = -errno;
37 		printk(UM_KERN_ERR "get_pty : Couldn't open /dev/ptmx - "
38 		       "err = %d\n", errno);
39 		return err;
40 	}
41 
42 	info.fd = fd;
43 	initial_thread_cb(grantpt_cb, &info);
44 
45 	if (info.res < 0) {
46 		err = -info.err;
47 		printk(UM_KERN_ERR "get_pty : Couldn't grant pty - "
48 		       "errno = %d\n", -info.err);
49 		goto out;
50 	}
51 
52 	if (unlockpt(fd) < 0) {
53 		err = -errno;
54 		printk(UM_KERN_ERR "get_pty : Couldn't unlock pty - "
55 		       "errno = %d\n", errno);
56 		goto out;
57 	}
58 	return fd;
59 out:
60 	close(fd);
61 	return err;
62 }
63