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168 lines
4.7 KiB
C
168 lines
4.7 KiB
C
/* Copyright (C) 1998-2020 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Zack Weinberg <zack@rabi.phys.columbia.edu>, 1998.
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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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<https://www.gnu.org/licenses/>. */
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#include <errno.h>
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#include <paths.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/ioctl.h>
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#include <sys/stat.h>
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#include <sys/sysmacros.h>
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#include <termios.h>
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#include <unistd.h>
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#include <_itoa.h>
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/* Check if DEV corresponds to a master pseudo terminal device. */
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#define MASTER_P(Dev) \
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(__gnu_dev_major ((Dev)) == 2 \
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|| (__gnu_dev_major ((Dev)) == 4 \
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&& __gnu_dev_minor ((Dev)) >= 128 && __gnu_dev_minor ((Dev)) < 192) \
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|| (__gnu_dev_major ((Dev)) >= 128 && __gnu_dev_major ((Dev)) < 136))
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/* Check if DEV corresponds to a slave pseudo terminal device. */
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#define SLAVE_P(Dev) \
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(__gnu_dev_major ((Dev)) == 3 \
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|| (__gnu_dev_major ((Dev)) == 4 \
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&& __gnu_dev_minor ((Dev)) >= 192 && __gnu_dev_minor ((Dev)) < 256) \
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|| (__gnu_dev_major ((Dev)) >= 136 && __gnu_dev_major ((Dev)) < 144))
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/* Note that major number 4 corresponds to the old BSD style pseudo
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terminal devices. As of Linux 2.1.115 these are no longer
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supported. They have been replaced by major numbers 2 (masters)
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and 3 (slaves). */
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/* Directory where we can find the slave pty nodes. */
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#define _PATH_DEVPTS "/dev/pts/"
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/* The are declared in getpt.c. */
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extern const char __libc_ptyname1[] attribute_hidden;
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extern const char __libc_ptyname2[] attribute_hidden;
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/* Static buffer for `ptsname'. */
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static char buffer[sizeof (_PATH_DEVPTS) + 20];
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/* Return the pathname of the pseudo terminal slave associated with
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the master FD is open on, or NULL on errors.
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The returned storage is good until the next call to this function. */
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char *
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ptsname (int fd)
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{
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return __ptsname_r (fd, buffer, sizeof (buffer)) != 0 ? NULL : buffer;
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}
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int
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__ptsname_internal (int fd, char *buf, size_t buflen, struct stat64 *stp)
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{
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int save_errno = errno;
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unsigned int ptyno;
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if (!__isatty (fd))
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{
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__set_errno (ENOTTY);
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return ENOTTY;
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}
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#ifdef TIOCGPTN
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if (__ioctl (fd, TIOCGPTN, &ptyno) == 0)
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{
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/* Buffer we use to print the number in. For a maximum size for
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`int' of 8 bytes we never need more than 20 digits. */
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char numbuf[21];
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const char *devpts = _PATH_DEVPTS;
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const size_t devptslen = strlen (_PATH_DEVPTS);
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char *p;
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numbuf[sizeof (numbuf) - 1] = '\0';
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p = _itoa_word (ptyno, &numbuf[sizeof (numbuf) - 1], 10, 0);
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if (buflen < devptslen + (&numbuf[sizeof (numbuf)] - p))
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{
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__set_errno (ERANGE);
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return ERANGE;
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}
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memcpy (__stpcpy (buf, devpts), p, &numbuf[sizeof (numbuf)] - p);
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}
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else if (errno != EINVAL)
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return errno;
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else
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#endif
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{
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char *p;
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if (buflen < strlen (_PATH_TTY) + 3)
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{
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__set_errno (ERANGE);
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return ERANGE;
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}
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if (__fxstat64 (_STAT_VER, fd, stp) < 0)
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return errno;
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/* Check if FD really is a master pseudo terminal. */
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if (! MASTER_P (stp->st_rdev))
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{
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__set_errno (ENOTTY);
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return ENOTTY;
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}
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ptyno = __gnu_dev_minor (stp->st_rdev);
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if (ptyno / 16 >= strlen (__libc_ptyname1))
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{
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__set_errno (ENOTTY);
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return ENOTTY;
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}
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p = __stpcpy (buf, _PATH_TTY);
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p[0] = __libc_ptyname1[ptyno / 16];
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p[1] = __libc_ptyname2[ptyno % 16];
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p[2] = '\0';
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}
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if (__xstat64 (_STAT_VER, buf, stp) < 0)
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return errno;
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/* Check if the name we're about to return really corresponds to a
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slave pseudo terminal. */
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if (! S_ISCHR (stp->st_mode) || ! SLAVE_P (stp->st_rdev))
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{
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/* This really is a configuration problem. */
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__set_errno (ENOTTY);
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return ENOTTY;
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}
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__set_errno (save_errno);
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return 0;
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}
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/* Store at most BUFLEN characters of the pathname of the slave pseudo
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terminal associated with the master FD is open on in BUF.
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Return 0 on success, otherwise an error number. */
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int
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__ptsname_r (int fd, char *buf, size_t buflen)
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{
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struct stat64 st;
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return __ptsname_internal (fd, buf, buflen, &st);
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}
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weak_alias (__ptsname_r, ptsname_r)
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