1 /* Copyright (C) 1991-2019 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
22 #include <sys/types.h>
33 static int getttyname_r (char *buf, size_t buflen,
34 const struct stat64 *mytty, int save,
38 attribute_compat_text_section
39 getttyname_r (char *buf, size_t buflen, const struct stat64 *mytty,
40 int save, int *dostat)
45 size_t devlen = strlen (buf);
47 dirstream = __opendir (buf);
48 if (dirstream == NULL)
54 while ((d = __readdir64 (dirstream)) != NULL)
55 if ((d->d_fileno == mytty->st_ino || *dostat)
56 && strcmp (d->d_name, "stdin")
57 && strcmp (d->d_name, "stdout")
58 && strcmp (d->d_name, "stderr"))
61 size_t needed = _D_EXACT_NAMLEN (d) + 1;
66 (void) __closedir (dirstream);
71 cp = __stpncpy (buf + devlen, d->d_name, needed);
74 if (__xstat64 (_STAT_VER, buf, &st) == 0
75 && is_mytty (mytty, &st))
77 (void) __closedir (dirstream);
83 (void) __closedir (dirstream);
85 /* It is not clear what to return in this case. `isatty' says FD
86 refers to a TTY but no entry in /dev has this inode. */
90 /* Store at most BUFLEN character of the pathname of the terminal FD is
91 open on in BUF. Return 0 on success, otherwise an error number. */
93 __ttyname_r (int fd, char *buf, size_t buflen)
96 struct stat64 st, st1;
101 /* Test for the absolute minimal size. This makes life easier inside
105 __set_errno (EINVAL);
109 if (buflen < sizeof ("/dev/pts/"))
111 __set_errno (ERANGE);
115 /* isatty check, tcgetattr is used because it sets the correct
116 errno (EBADF resp. ENOTTY) on error. */
118 if (__glibc_unlikely (__tcgetattr (fd, &term) < 0))
121 if (__fxstat64 (_STAT_VER, fd, &st) < 0)
124 /* We try using the /proc filesystem. */
125 *_fitoa_word (fd, __stpcpy (procname, "/proc/self/fd/"), 10, 0) = '\0';
127 ssize_t ret = __readlink (procname, buf, buflen - 1);
128 if (__glibc_unlikely (ret == -1 && errno == ENAMETOOLONG))
130 __set_errno (ERANGE);
134 if (__glibc_likely (ret != -1))
136 #define UNREACHABLE_LEN strlen ("(unreachable)")
137 if (ret > UNREACHABLE_LEN
138 && memcmp (buf, "(unreachable)", UNREACHABLE_LEN) == 0)
140 memmove (buf, buf + UNREACHABLE_LEN, ret - UNREACHABLE_LEN);
141 ret -= UNREACHABLE_LEN;
144 /* readlink need not terminate the string. */
147 /* Verify readlink result, fall back on iterating through devices. */
149 && __xstat64 (_STAT_VER, buf, &st1) == 0
150 && is_mytty (&st, &st1))
156 /* Prepare the result buffer. */
157 memcpy (buf, "/dev/pts/", sizeof ("/dev/pts/"));
158 buflen -= sizeof ("/dev/pts/") - 1;
160 if (__xstat64 (_STAT_VER, buf, &st1) == 0 && S_ISDIR (st1.st_mode))
162 ret = getttyname_r (buf, buflen, &st, save,
171 if (ret && dostat != -1)
173 buf[sizeof ("/dev/") - 1] = '\0';
174 buflen += sizeof ("pts/") - 1;
175 ret = getttyname_r (buf, buflen, &st, save,
179 if (ret && dostat != -1)
181 buf[sizeof ("/dev/") - 1] = '\0';
183 ret = getttyname_r (buf, buflen, &st,
187 if (ret && doispty && is_pty (&st))
189 /* We failed to figure out the TTY's name, but we can at least
190 signal that we did verify that it really is a PTY slave.
191 This happens when we have inherited the file descriptor from
192 a different mount namespace. */
193 __set_errno (ENODEV);
200 weak_alias (__ttyname_r, ttyname_r)