83 lines
2.5 KiB
C
83 lines
2.5 KiB
C
/* Copyright (C) 1998-2022 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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<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 <termios.h>
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#include <unistd.h>
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#include <_itoa.h>
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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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/* 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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/* 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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int save_errno = errno;
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unsigned int ptyno;
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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
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/* Bad file descriptor, or not a ptmx descriptor. */
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return errno;
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__set_errno (save_errno);
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return 0;
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}
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libc_hidden_def (__ptsname_r)
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weak_alias (__ptsname_r, ptsname_r)
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