1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
|
/* Copyright (C) 1998-2014 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Zack Weinberg <zack@rabi.phys.columbia.edu>, 1998.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <grp.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include "pty-private.h"
/* Return the result of ptsname_r in the buffer pointed to by PTS,
which should be of length BUF_LEN. If it is too long to fit in
this buffer, a sufficiently long buffer is allocated using malloc,
and returned in PTS. 0 is returned upon success, -1 otherwise. */
static int
pts_name (int fd, char **pts, size_t buf_len, struct stat64 *stp)
{
int rv;
char *buf = *pts;
for (;;)
{
char *new_buf;
if (buf_len)
{
rv = __ptsname_internal (fd, buf, buf_len, stp);
if (rv != 0)
{
if (rv == ENOTTY)
/* ptsname_r returns with ENOTTY to indicate
a descriptor not referring to a pty master.
For this condition, grantpt must return EINVAL. */
rv = EINVAL;
errno = rv; /* Not necessarily set by __ptsname_r. */
break;
}
if (memchr (buf, '\0', buf_len))
/* We succeeded and the returned name fit in the buffer. */
break;
/* Try again with a longer buffer. */
buf_len += buf_len; /* Double it */
}
else
/* No initial buffer; start out by mallocing one. */
buf_len = 128; /* First time guess. */
if (buf != *pts)
/* We've already malloced another buffer at least once. */
new_buf = (char *) realloc (buf, buf_len);
else
new_buf = (char *) malloc (buf_len);
if (! new_buf)
{
rv = -1;
__set_errno (ENOMEM);
break;
}
buf = new_buf;
}
if (rv == 0)
*pts = buf; /* Return buffer to the user. */
else if (buf != *pts)
free (buf); /* Free what we malloced when returning an error. */
return rv;
}
/* Change the ownership and access permission of the slave pseudo
terminal associated with the master pseudo terminal specified
by FD. */
int
grantpt (int fd)
{
int retval = -1;
#ifdef PATH_MAX
char _buf[PATH_MAX];
#else
char _buf[512];
#endif
char *buf = _buf;
struct stat64 st;
if (__glibc_unlikely (pts_name (fd, &buf, sizeof (_buf), &st)))
{
int save_errno = errno;
/* Check, if the file descriptor is valid. pts_name returns the
wrong errno number, so we cannot use that. */
if (__libc_fcntl (fd, F_GETFD) == -1 && errno == EBADF)
return -1;
/* If the filedescriptor is no TTY, grantpt has to set errno
to EINVAL. */
if (save_errno == ENOTTY)
__set_errno (EINVAL);
else
__set_errno (save_errno);
return -1;
}
/* Make sure that we own the device. */
uid_t uid = __getuid ();
if (st.st_uid != uid)
{
if (__chown (buf, uid, st.st_gid) < 0)
goto helper;
}
static int tty_gid = -1;
if (__glibc_unlikely (tty_gid == -1))
{
char *grtmpbuf;
struct group grbuf;
size_t grbuflen = __sysconf (_SC_GETGR_R_SIZE_MAX);
struct group *p;
/* Get the group ID of the special `tty' group. */
if (grbuflen == (size_t) -1L)
/* `sysconf' does not support _SC_GETGR_R_SIZE_MAX.
Try a moderate value. */
grbuflen = 1024;
grtmpbuf = (char *) __alloca (grbuflen);
__getgrnam_r (TTY_GROUP, &grbuf, grtmpbuf, grbuflen, &p);
if (p != NULL)
tty_gid = p->gr_gid;
}
gid_t gid = tty_gid == -1 ? __getgid () : tty_gid;
/* Make sure the group of the device is that special group. */
if (st.st_gid != gid)
{
if (__chown (buf, uid, gid) < 0)
goto helper;
}
/* Make sure the permission mode is set to readable and writable by
the owner, and writable by the group. */
if ((st.st_mode & ACCESSPERMS) != (S_IRUSR|S_IWUSR|S_IWGRP))
{
if (__chmod (buf, S_IRUSR|S_IWUSR|S_IWGRP) < 0)
goto helper;
}
retval = 0;
goto cleanup;
/* We have to use the helper program if it is available. */
helper:;
#ifdef HAVE_PT_CHOWN
pid_t pid = __fork ();
if (pid == -1)
goto cleanup;
else if (pid == 0)
{
/* Disable core dumps. */
struct rlimit rl = { 0, 0 };
__setrlimit (RLIMIT_CORE, &rl);
/* We pass the master pseudo terminal as file descriptor PTY_FILENO. */
if (fd != PTY_FILENO)
if (__dup2 (fd, PTY_FILENO) < 0)
_exit (FAIL_EBADF);
# ifdef CLOSE_ALL_FDS
CLOSE_ALL_FDS ();
# endif
execle (_PATH_PT_CHOWN, basename (_PATH_PT_CHOWN), NULL, NULL);
_exit (FAIL_EXEC);
}
else
{
int w;
if (__waitpid (pid, &w, 0) == -1)
goto cleanup;
if (!WIFEXITED (w))
__set_errno (ENOEXEC);
else
switch (WEXITSTATUS (w))
{
case 0:
retval = 0;
break;
case FAIL_EBADF:
__set_errno (EBADF);
break;
case FAIL_EINVAL:
__set_errno (EINVAL);
break;
case FAIL_EACCES:
__set_errno (EACCES);
break;
case FAIL_EXEC:
__set_errno (ENOEXEC);
break;
case FAIL_ENOMEM:
__set_errno (ENOMEM);
break;
default:
assert(! "grantpt: internal error: invalid exit code from pt_chown");
}
}
#endif
cleanup:
if (buf != _buf)
free (buf);
return retval;
}
|
