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
|
/* Copyright (C) 1998 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 Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <assert.h>
#include <errno.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"
libc_hidden_proto(memchr)
libc_hidden_proto(getgid)
libc_hidden_proto(getuid)
libc_hidden_proto(setrlimit)
libc_hidden_proto(waitpid)
libc_hidden_proto(dup2)
libc_hidden_proto(chmod)
libc_hidden_proto(chown)
libc_hidden_proto(vfork)
libc_hidden_proto(fork)
libc_hidden_proto(stat)
libc_hidden_proto(ptsname_r)
libc_hidden_proto(execle)
libc_hidden_proto(_exit)
/* uClinux-2.0 has vfork, but Linux 2.0 doesn't */
#include <sys/syscall.h>
#if ! defined __NR_vfork
#define vfork fork
#endif
/* 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)
{
int rv;
char *buf = *pts;
for (;;)
{
char *new_buf;
if (buf_len)
{
rv = ptsname_r (fd, buf, buf_len);
if (rv != 0 || memchr (buf, '\0', buf_len))
/* We either got an error, or 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 = realloc (buf, buf_len);
else
new_buf = malloc (buf_len);
if (! new_buf)
{
rv = -1;
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 stat st;
uid_t uid;
gid_t gid;
pid_t pid;
if (pts_name (fd, &buf, sizeof (_buf)))
return -1;
if (stat(buf, &st) < 0)
goto cleanup;
/* Make sure that we own the device. */
uid = getuid ();
if (st.st_uid != uid)
{
if (chown (buf, uid, st.st_gid) < 0)
goto helper;
}
gid = getgid ();
/* 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. */
helper:
pid = vfork ();
if (pid == -1)
goto cleanup;
else if (pid == 0)
{
/* Disable core dumps. */
struct rlimit rl = { 0, 0 };
setrlimit (RLIMIT_CORE, &rl);
/* We pase the master pseudo terminal as file descriptor PTY_FILENO. */
if (fd != PTY_FILENO)
if (dup2 (fd, PTY_FILENO) < 0)
_exit (FAIL_EBADF);
execle (_PATH_PT_CHOWN, _PATH_PT_CHOWN, NULL, NULL);
_exit (FAIL_EXEC);
}
else
{
int w;
if (waitpid (pid, &w, 0) == -1)
goto cleanup;
if (!WIFEXITED (w))
errno = ENOEXEC;
else
switch (WEXITSTATUS(w))
{
case 0:
retval = 0;
break;
case FAIL_EBADF:
errno = EBADF;
break;
case FAIL_EINVAL:
errno = EINVAL;
break;
case FAIL_EACCES:
errno = EACCES;
break;
case FAIL_EXEC:
errno = ENOEXEC;
break;
default:
assert(! "getpt: internal error: invalid exit code from pt_chown");
}
}
cleanup:
if (buf != _buf)
free (buf);
return retval;
}
|
