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glibc/sysdeps/unix/sysv/linux/ttyname.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> | |
#if 0 | |
/* Is this used anywhere? It is not exported. */ | |
char *__ttyname; | |
#endif | |
static char *getttyname (const char *dev, dev_t mydev, | |
ino64_t myino, int save, int *dostat) | |
internal_function; | |
libc_freeres_ptr (static char *getttyname_name); | |
static char * | |
internal_function attribute_compat_text_section | |
getttyname (const char *dev, dev_t mydev, ino64_t myino, int save, int *dostat) | |
{ | |
static size_t namelen; | |
struct stat64 st; | |
DIR *dirstream; | |
struct dirent64 *d; | |
size_t devlen = strlen (dev) + 1; | |
dirstream = __opendir (dev); | |
if (dirstream == NULL) | |
{ | |
*dostat = -1; | |
return NULL; | |
} | |
/* Prepare for the loop. If we already have a buffer copy the directory | |
name we look at into it. */ | |
if (devlen < namelen) | |
*((char *) __mempcpy (getttyname_name, dev, devlen - 1)) = '/'; | |
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")) | |
{ | |
size_t dlen = _D_ALLOC_NAMLEN (d); | |
if (devlen + dlen > namelen) | |
{ | |
free (getttyname_name); | |
namelen = 2 * (devlen + dlen); /* Big enough. */ | |
getttyname_name = malloc (namelen); | |
if (! getttyname_name) | |
{ | |
*dostat = -1; | |
/* Perhaps it helps to free the directory stream buffer. */ | |
(void) __closedir (dirstream); | |
return NULL; | |
} | |
*((char *) __mempcpy (getttyname_name, dev, devlen - 1)) = '/'; | |
} | |
memcpy (&getttyname_name[devlen], d->d_name, dlen); | |
if (__xstat64 (_STAT_VER, getttyname_name, &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); | |
#if 0 | |
__ttyname = getttyname_name; | |
#endif | |
__set_errno (save); | |
return getttyname_name; | |
} | |
} | |
(void) __closedir (dirstream); | |
__set_errno (save); | |
return NULL; | |
} | |
/* Static buffer in `ttyname'. */ | |
libc_freeres_ptr (static char *ttyname_buf); | |
/* Return the pathname of the terminal FD is open on, or NULL on errors. | |
The returned storage is good only until the next call to this function. */ | |
char * | |
ttyname (int fd) | |
{ | |
static size_t buflen; | |
char procname[30]; | |
struct stat64 st, st1; | |
int dostat = 0; | |
char *name; | |
int save = errno; | |
struct termios term; | |
/* isatty check, tcgetattr is used because it sets the correct | |
errno (EBADF resp. ENOTTY) on error. */ | |
if (__glibc_unlikely (__tcgetattr (fd, &term) < 0)) | |
return NULL; | |
if (__fxstat64 (_STAT_VER, fd, &st) < 0) | |
return NULL; | |
/* We try using the /proc filesystem. */ | |
*_fitoa_word (fd, __stpcpy (procname, "/proc/self/fd/"), 10, 0) = '\0'; | |
if (buflen == 0) | |
{ | |
buflen = 4095; | |
ttyname_buf = (char *) malloc (buflen + 1); | |
if (ttyname_buf == NULL) | |
{ | |
buflen = 0; | |
return NULL; | |
} | |
} | |
ssize_t len = __readlink (procname, ttyname_buf, buflen); | |
if (__glibc_likely (len != -1)) | |
{ | |
if ((size_t) len >= buflen) | |
return NULL; | |
#define UNREACHABLE_LEN strlen ("(unreachable)") | |
if (len > UNREACHABLE_LEN | |
&& memcmp (ttyname_buf, "(unreachable)", UNREACHABLE_LEN) == 0) | |
{ | |
memmove (ttyname_buf, ttyname_buf + UNREACHABLE_LEN, | |
len - UNREACHABLE_LEN); | |
len -= UNREACHABLE_LEN; | |
} | |
/* readlink need not terminate the string. */ | |
ttyname_buf[len] = '\0'; | |
/* Verify readlink result, fall back on iterating through devices. */ | |
if (ttyname_buf[0] == '/' | |
&& __xstat64 (_STAT_VER, ttyname_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 ttyname_buf; | |
} | |
if (__xstat64 (_STAT_VER, "/dev/pts", &st1) == 0 && S_ISDIR (st1.st_mode)) | |
{ | |
#ifdef _STATBUF_ST_RDEV | |
name = getttyname ("/dev/pts", st.st_rdev, st.st_ino, save, &dostat); | |
#else | |
name = getttyname ("/dev/pts", st.st_dev, st.st_ino, save, &dostat); | |
#endif | |
} | |
else | |
{ | |
__set_errno (save); | |
name = NULL; | |
} | |
if (!name && dostat != -1) | |
{ | |
#ifdef _STATBUF_ST_RDEV | |
name = getttyname ("/dev", st.st_rdev, st.st_ino, save, &dostat); | |
#else | |
name = getttyname ("/dev", st.st_dev, st.st_ino, save, &dostat); | |
#endif | |
} | |
if (!name && dostat != -1) | |
{ | |
dostat = 1; | |
#ifdef _STATBUF_ST_RDEV | |
name = getttyname ("/dev", st.st_rdev, st.st_ino, save, &dostat); | |
#else | |
name = getttyname ("/dev", st.st_dev, st.st_ino, save, &dostat); | |
#endif | |
} | |
return name; | |
} |