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glibc/sysdeps/unix/sysv/linux/ttyname_r.c
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/* Copyright (C) 1991-2016 Free Software Foundation, Inc. | |
This file is part of the GNU C Library. | |
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 <errno.h> | |
#include <limits.h> | |
#include <stddef.h> | |
#include <dirent.h> | |
#include <sys/types.h> | |
#include <sys/stat.h> | |
#include <termios.h> | |
#include <unistd.h> | |
#include <string.h> | |
#include <stdlib.h> | |
#include <_itoa.h> | |
static int getttyname_r (char *buf, size_t buflen, | |
dev_t mydev, ino64_t myino, int save, | |
int *dostat) internal_function; | |
static int | |
internal_function attribute_compat_text_section | |
getttyname_r (char *buf, size_t buflen, dev_t mydev, ino64_t myino, | |
int save, int *dostat) | |
{ | |
struct stat64 st; | |
DIR *dirstream; | |
struct dirent64 *d; | |
size_t devlen = strlen (buf); | |
dirstream = __opendir (buf); | |
if (dirstream == NULL) | |
{ | |
*dostat = -1; | |
return errno; | |
} | |
while ((d = __readdir64 (dirstream)) != NULL) | |
if ((d->d_fileno == myino || *dostat) | |
&& strcmp (d->d_name, "stdin") | |
&& strcmp (d->d_name, "stdout") | |
&& strcmp (d->d_name, "stderr")) | |
{ | |
char *cp; | |
size_t needed = _D_EXACT_NAMLEN (d) + 1; | |
if (needed > buflen) | |
{ | |
*dostat = -1; | |
(void) __closedir (dirstream); | |
__set_errno (ERANGE); | |
return ERANGE; | |
} | |
cp = __stpncpy (buf + devlen, d->d_name, needed); | |
cp[0] = '\0'; | |
if (__xstat64 (_STAT_VER, buf, &st) == 0 | |
#ifdef _STATBUF_ST_RDEV | |
&& S_ISCHR (st.st_mode) && st.st_rdev == mydev | |
#else | |
&& d->d_fileno == myino && st.st_dev == mydev | |
#endif | |
) | |
{ | |
(void) __closedir (dirstream); | |
__set_errno (save); | |
return 0; | |
} | |
} | |
(void) __closedir (dirstream); | |
__set_errno (save); | |
/* It is not clear what to return in this case. `isatty' says FD | |
refers to a TTY but no entry in /dev has this inode. */ | |
return ENOTTY; | |
} | |
/* Store at most BUFLEN character of the pathname of the terminal FD is | |
open on in BUF. Return 0 on success, otherwise an error number. */ | |
int | |
__ttyname_r (int fd, char *buf, size_t buflen) | |
{ | |
char procname[30]; | |
struct stat64 st, st1; | |
int dostat = 0; | |
int save = errno; | |
/* Test for the absolute minimal size. This makes life easier inside | |
the loop. */ | |
if (!buf) | |
{ | |
__set_errno (EINVAL); | |
return EINVAL; | |
} | |
if (buflen < sizeof ("/dev/pts/")) | |
{ | |
__set_errno (ERANGE); | |
return ERANGE; | |
} | |
/* isatty check, tcgetattr is used because it sets the correct | |
errno (EBADF resp. ENOTTY) on error. */ | |
struct termios term; | |
if (__glibc_unlikely (__tcgetattr (fd, &term) < 0)) | |
return errno; | |
if (__fxstat64 (_STAT_VER, fd, &st) < 0) | |
return errno; | |
/* We try using the /proc filesystem. */ | |
*_fitoa_word (fd, __stpcpy (procname, "/proc/self/fd/"), 10, 0) = '\0'; | |
ssize_t ret = __readlink (procname, buf, buflen - 1); | |
if (__glibc_unlikely (ret == -1 && errno == ENAMETOOLONG)) | |
{ | |
__set_errno (ERANGE); | |
return ERANGE; | |
} | |
if (__glibc_likely (ret != -1)) | |
{ | |
#define UNREACHABLE_LEN strlen ("(unreachable)") | |
if (ret > UNREACHABLE_LEN | |
&& memcmp (buf, "(unreachable)", UNREACHABLE_LEN) == 0) | |
{ | |
memmove (buf, buf + UNREACHABLE_LEN, ret - UNREACHABLE_LEN); | |
ret -= UNREACHABLE_LEN; | |
} | |
/* readlink need not terminate the string. */ | |
buf[ret] = '\0'; | |
/* Verify readlink result, fall back on iterating through devices. */ | |
if (buf[0] == '/' | |
&& __xstat64 (_STAT_VER, buf, &st1) == 0 | |
#ifdef _STATBUF_ST_RDEV | |
&& S_ISCHR (st1.st_mode) | |
&& st1.st_rdev == st.st_rdev | |
#else | |
&& st1.st_ino == st.st_ino | |
&& st1.st_dev == st.st_dev | |
#endif | |
) | |
return 0; | |
} | |
/* Prepare the result buffer. */ | |
memcpy (buf, "/dev/pts/", sizeof ("/dev/pts/")); | |
buflen -= sizeof ("/dev/pts/") - 1; | |
if (__xstat64 (_STAT_VER, buf, &st1) == 0 && S_ISDIR (st1.st_mode)) | |
{ | |
#ifdef _STATBUF_ST_RDEV | |
ret = getttyname_r (buf, buflen, st.st_rdev, st.st_ino, save, | |
&dostat); | |
#else | |
ret = getttyname_r (buf, buflen, st.st_dev, st.st_ino, save, | |
&dostat); | |
#endif | |
} | |
else | |
{ | |
__set_errno (save); | |
ret = ENOENT; | |
} | |
if (ret && dostat != -1) | |
{ | |
buf[sizeof ("/dev/") - 1] = '\0'; | |
buflen += sizeof ("pts/") - 1; | |
#ifdef _STATBUF_ST_RDEV | |
ret = getttyname_r (buf, buflen, st.st_rdev, st.st_ino, save, | |
&dostat); | |
#else | |
ret = getttyname_r (buf, buflen, st.st_dev, st.st_ino, save, | |
&dostat); | |
#endif | |
} | |
if (ret && dostat != -1) | |
{ | |
buf[sizeof ("/dev/") - 1] = '\0'; | |
dostat = 1; | |
#ifdef _STATBUF_ST_RDEV | |
ret = getttyname_r (buf, buflen, st.st_rdev, st.st_ino, | |
save, &dostat); | |
#else | |
ret = getttyname_r (buf, buflen, st.st_dev, st.st_ino, | |
save, &dostat); | |
#endif | |
} | |
return ret; | |
} | |
weak_alias (__ttyname_r, ttyname_r) |