1 /* Copyright (C) 1998-2014 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Zack Weinberg <zack@rabi.phys.columbia.edu>, 1998.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
26 #include <sys/resource.h>
28 #include <sys/types.h>
32 #include "pty-private.h"
35 /* Return the result of ptsname_r in the buffer pointed to by PTS,
36 which should be of length BUF_LEN. If it is too long to fit in
37 this buffer, a sufficiently long buffer is allocated using malloc,
38 and returned in PTS. 0 is returned upon success, -1 otherwise. */
40 pts_name (int fd, char **pts, size_t buf_len, struct stat64 *stp)
51 rv = __ptsname_internal (fd, buf, buf_len, stp);
55 /* ptsname_r returns with ENOTTY to indicate
56 a descriptor not referring to a pty master.
57 For this condition, grantpt must return EINVAL. */
59 errno = rv; /* Not necessarily set by __ptsname_r. */
63 if (memchr (buf, '\0', buf_len))
64 /* We succeeded and the returned name fit in the buffer. */
67 /* Try again with a longer buffer. */
68 buf_len += buf_len; /* Double it */
71 /* No initial buffer; start out by mallocing one. */
72 buf_len = 128; /* First time guess. */
75 /* We've already malloced another buffer at least once. */
76 new_buf = (char *) realloc (buf, buf_len);
78 new_buf = (char *) malloc (buf_len);
89 *pts = buf; /* Return buffer to the user. */
91 free (buf); /* Free what we malloced when returning an error. */
96 /* Change the ownership and access permission of the slave pseudo
97 terminal associated with the master pseudo terminal specified
111 if (__glibc_unlikely (pts_name (fd, &buf, sizeof (_buf), &st)))
113 int save_errno = errno;
115 /* Check, if the file descriptor is valid. pts_name returns the
116 wrong errno number, so we cannot use that. */
117 if (__libc_fcntl (fd, F_GETFD) == -1 && errno == EBADF)
120 /* If the filedescriptor is no TTY, grantpt has to set errno
122 if (save_errno == ENOTTY)
123 __set_errno (EINVAL);
125 __set_errno (save_errno);
130 /* Make sure that we own the device. */
131 uid_t uid = __getuid ();
132 if (st.st_uid != uid)
134 if (__chown (buf, uid, st.st_gid) < 0)
138 static int tty_gid = -1;
139 if (__glibc_unlikely (tty_gid == -1))
143 size_t grbuflen = __sysconf (_SC_GETGR_R_SIZE_MAX);
146 /* Get the group ID of the special `tty' group. */
147 if (grbuflen == (size_t) -1L)
148 /* `sysconf' does not support _SC_GETGR_R_SIZE_MAX.
149 Try a moderate value. */
151 grtmpbuf = (char *) __alloca (grbuflen);
152 __getgrnam_r (TTY_GROUP, &grbuf, grtmpbuf, grbuflen, &p);
156 gid_t gid = tty_gid == -1 ? __getgid () : tty_gid;
158 /* Make sure the group of the device is that special group. */
159 if (st.st_gid != gid)
161 if (__chown (buf, uid, gid) < 0)
165 /* Make sure the permission mode is set to readable and writable by
166 the owner, and writable by the group. */
167 if ((st.st_mode & ACCESSPERMS) != (S_IRUSR|S_IWUSR|S_IWGRP))
169 if (__chmod (buf, S_IRUSR|S_IWUSR|S_IWGRP) < 0)
176 /* We have to use the helper program if it is available. */
180 pid_t pid = __fork ();
185 /* Disable core dumps. */
186 struct rlimit rl = { 0, 0 };
187 __setrlimit (RLIMIT_CORE, &rl);
189 /* We pass the master pseudo terminal as file descriptor PTY_FILENO. */
190 if (fd != PTY_FILENO)
191 if (__dup2 (fd, PTY_FILENO) < 0)
194 # ifdef CLOSE_ALL_FDS
198 execle (_PATH_PT_CHOWN, basename (_PATH_PT_CHOWN), NULL, NULL);
205 if (__waitpid (pid, &w, 0) == -1)
208 __set_errno (ENOEXEC);
210 switch (WEXITSTATUS (w))
219 __set_errno (EINVAL);
222 __set_errno (EACCES);
225 __set_errno (ENOEXEC);
228 __set_errno (ENOMEM);
232 assert(! "grantpt: internal error: invalid exit code from pt_chown");