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04277e02d7
* All files with FSF copyright notices: Update copyright dates using scripts/update-copyrights. * locale/programs/charmap-kw.h: Regenerated. * locale/programs/locfile-kw.h: Likewise.
205 lines
5.2 KiB
C
205 lines
5.2 KiB
C
/* Copyright (C) 1991-2019 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <errno.h>
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#include <limits.h>
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#include <stddef.h>
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#include <dirent.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <termios.h>
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#include <unistd.h>
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#include <string.h>
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#include <stdlib.h>
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#include <_itoa.h>
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#include "ttyname.h"
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#if 0
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/* Is this used anywhere? It is not exported. */
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char *__ttyname;
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#endif
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static char *getttyname (const char *dev, const struct stat64 *mytty,
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int save, int *dostat);
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libc_freeres_ptr (static char *getttyname_name);
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static char *
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attribute_compat_text_section
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getttyname (const char *dev, const struct stat64 *mytty, int save, int *dostat)
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{
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static size_t namelen;
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struct stat64 st;
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DIR *dirstream;
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struct dirent64 *d;
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size_t devlen = strlen (dev) + 1;
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dirstream = __opendir (dev);
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if (dirstream == NULL)
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{
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*dostat = -1;
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return NULL;
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}
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/* Prepare for the loop. If we already have a buffer copy the directory
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name we look at into it. */
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if (devlen < namelen)
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*((char *) __mempcpy (getttyname_name, dev, devlen - 1)) = '/';
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while ((d = __readdir64 (dirstream)) != NULL)
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if ((d->d_fileno == mytty->st_ino || *dostat)
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&& strcmp (d->d_name, "stdin")
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&& strcmp (d->d_name, "stdout")
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&& strcmp (d->d_name, "stderr"))
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{
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size_t dlen = _D_ALLOC_NAMLEN (d);
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if (devlen + dlen > namelen)
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{
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free (getttyname_name);
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namelen = 2 * (devlen + dlen); /* Big enough. */
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getttyname_name = malloc (namelen);
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if (! getttyname_name)
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{
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*dostat = -1;
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/* Perhaps it helps to free the directory stream buffer. */
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(void) __closedir (dirstream);
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return NULL;
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}
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*((char *) __mempcpy (getttyname_name, dev, devlen - 1)) = '/';
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}
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memcpy (&getttyname_name[devlen], d->d_name, dlen);
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if (__xstat64 (_STAT_VER, getttyname_name, &st) == 0
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&& is_mytty (mytty, &st))
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{
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(void) __closedir (dirstream);
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#if 0
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__ttyname = getttyname_name;
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#endif
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__set_errno (save);
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return getttyname_name;
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}
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}
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(void) __closedir (dirstream);
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__set_errno (save);
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return NULL;
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}
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/* Static buffer in `ttyname'. */
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libc_freeres_ptr (static char *ttyname_buf);
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/* Return the pathname of the terminal FD is open on, or NULL on errors.
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The returned storage is good only until the next call to this function. */
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char *
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ttyname (int fd)
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{
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static size_t buflen;
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char procname[30];
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struct stat64 st, st1;
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int dostat = 0;
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int doispty = 0;
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char *name;
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int save = errno;
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struct termios term;
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/* isatty check, tcgetattr is used because it sets the correct
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errno (EBADF resp. ENOTTY) on error. */
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if (__glibc_unlikely (__tcgetattr (fd, &term) < 0))
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return NULL;
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if (__fxstat64 (_STAT_VER, fd, &st) < 0)
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return NULL;
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/* We try using the /proc filesystem. */
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*_fitoa_word (fd, __stpcpy (procname, "/proc/self/fd/"), 10, 0) = '\0';
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if (buflen == 0)
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{
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buflen = 4095;
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ttyname_buf = (char *) malloc (buflen + 1);
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if (ttyname_buf == NULL)
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{
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buflen = 0;
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return NULL;
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}
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}
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ssize_t len = __readlink (procname, ttyname_buf, buflen);
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if (__glibc_likely (len != -1))
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{
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if ((size_t) len >= buflen)
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return NULL;
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#define UNREACHABLE_LEN strlen ("(unreachable)")
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if (len > UNREACHABLE_LEN
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&& memcmp (ttyname_buf, "(unreachable)", UNREACHABLE_LEN) == 0)
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{
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memmove (ttyname_buf, ttyname_buf + UNREACHABLE_LEN,
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len - UNREACHABLE_LEN);
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len -= UNREACHABLE_LEN;
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}
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/* readlink need not terminate the string. */
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ttyname_buf[len] = '\0';
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/* Verify readlink result, fall back on iterating through devices. */
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if (ttyname_buf[0] == '/'
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&& __xstat64 (_STAT_VER, ttyname_buf, &st1) == 0
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&& is_mytty (&st, &st1))
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return ttyname_buf;
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doispty = 1;
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}
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if (__xstat64 (_STAT_VER, "/dev/pts", &st1) == 0 && S_ISDIR (st1.st_mode))
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{
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name = getttyname ("/dev/pts", &st, save, &dostat);
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}
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else
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{
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__set_errno (save);
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name = NULL;
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}
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if (!name && dostat != -1)
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{
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name = getttyname ("/dev", &st, save, &dostat);
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}
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if (!name && dostat != -1)
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{
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dostat = 1;
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name = getttyname ("/dev", &st, save, &dostat);
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}
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if (!name && doispty && is_pty (&st))
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{
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/* We failed to figure out the TTY's name, but we can at least
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signal that we did verify that it really is a PTY slave.
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This happens when we have inherited the file descriptor from
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a different mount namespace. */
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__set_errno (ENODEV);
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return NULL;
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}
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return name;
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}
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