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-rw-r--r--libc/stdlib/ptsname.c171
1 files changed, 171 insertions, 0 deletions
diff --git a/libc/stdlib/ptsname.c b/libc/stdlib/ptsname.c
new file mode 100644
index 000000000..2fbc6be49
--- /dev/null
+++ b/libc/stdlib/ptsname.c
@@ -0,0 +1,171 @@
+/* Copyright (C) 1998 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Zack Weinberg <zack@rabi.phys.columbia.edu>, 1998.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Library General Public License as
+ published by the Free Software Foundation; either version 2 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
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If not,
+ write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+#include <errno.h>
+#include <paths.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <sys/sysmacros.h>
+#include <termios.h>
+#include <unistd.h>
+
+/* Check if DEV corresponds to a master pseudo terminal device. */
+#define MASTER_P(Dev) \
+ (major ((Dev)) == 2 \
+ || (major ((Dev)) == 4 && minor ((Dev)) >= 128 && minor ((Dev)) < 192) \
+ || (major ((Dev)) >= 128 && major ((Dev)) < 136))
+
+/* Check if DEV corresponds to a master pseudo terminal device. */
+#define SLAVE_P(Dev) \
+ (major ((Dev)) == 3 \
+ || (major ((Dev)) == 4 && minor ((Dev)) >= 192 && minor ((Dev)) < 256) \
+ || (major ((Dev)) >= 136 && major ((Dev)) < 144))
+
+/* Note that major number 4 corresponds to the old BSD style pseudo
+ terminal devices. As of Linux 2.1.115 these are no longer
+ supported. They have been replaced by major numbers 2 (masters)
+ and 3 (slaves). */
+
+/* Directory where we can find the slave pty nodes. */
+#define _PATH_DEVPTS "/dev/pts/"
+
+/* The are declared in getpt.c. */
+extern const char _ptyname1[];
+extern const char _ptyname2[];
+
+/* Static buffer for `ptsname'. */
+static char buffer[sizeof (_PATH_DEVPTS) + 20];
+
+/*
+extern char *
+_itoa_word (unsigned long value, char *buflim,
+ unsigned int base, int upper_case);
+*/
+
+
+/* Store at most BUFLEN characters of the pathname of the slave pseudo
+ terminal associated with the master FD is open on in BUF.
+ Return 0 on success, otherwise an error number. */
+int ptsname_r (int fd, char *buf, size_t buflen)
+{
+ int save_errno = errno;
+ struct stat st;
+ int ptyno;
+
+ if (buf == NULL)
+ {
+ errno = EINVAL;
+ return EINVAL;
+ }
+
+ if (!isatty (fd))
+ {
+ errno = ENOTTY;
+ return ENOTTY;
+ }
+#if 0
+#ifdef TIOCGPTN
+ if (ioctl (fd, TIOCGPTN, &ptyno) == 0)
+ {
+ /* Buffer we use to print the number in. For a maximum size for
+ `int' of 8 bytes we never need more than 20 digits. */
+ char numbuf[21];
+ const char *devpts = _PATH_DEVPTS;
+ const size_t devptslen = strlen (devpts);
+ char *p;
+
+ numbuf[20] = '\0';
+ p = _itoa_word (ptyno, &numbuf[20], 10, 0);
+
+ if (buflen < devptslen + strlen (p) + 1)
+ {
+ errno = ERANGE;
+ return ERANGE;
+ }
+
+ strcpy (buf, devpts);
+ strcat (buf, p);
+ }
+ else if (errno == EINVAL)
+#endif
+#endif
+ {
+ char *p;
+
+ if (buflen < strlen (_PATH_TTY) + 3)
+ {
+ errno = ERANGE;
+ return ERANGE;
+ }
+
+ if (fstat (fd, &st) < 0)
+ return errno;
+
+ /* Check if FD really is a master pseudo terminal. */
+ if (! MASTER_P (st.st_rdev))
+ {
+ errno = ENOTTY;
+ return ENOTTY;
+ }
+
+ ptyno = minor (st.st_rdev);
+ /* This is for the old BSD pseudo terminals. As of Linux
+ 2.1.115 these are no longer supported. */
+ if (major (st.st_rdev) == 4)
+ ptyno -= 128;
+
+ if (ptyno / 16 >= strlen (_ptyname1))
+ {
+ errno = ENOTTY;
+ return ENOTTY;
+ }
+
+ strcpy (buf, _PATH_TTY);
+ p = buf + strlen (buf);
+ p[0] = _ptyname1[ptyno / 16];
+ p[1] = _ptyname2[ptyno % 16];
+ p[2] = '\0';
+ }
+
+ if (_xstat (_STAT_VER, buf, &st) < 0)
+ return errno;
+
+ /* Check if the name we're about to return really corresponds to a
+ slave pseudo terminal. */
+ if (! S_ISCHR (st.st_mode) || ! SLAVE_P (st.st_rdev))
+ {
+ /* This really is a configuration problem. */
+ errno = ENOTTY;
+ return ENOTTY;
+ }
+
+ errno = save_errno;
+ return 0;
+}
+
+/* Return the pathname of the pseudo terminal slave assoicated with
+ the master FD is open on, or NULL on errors.
+ The returned storage is good until the next call to this function. */
+char *
+ptsname (int fd)
+{
+ return ptsname_r (fd, buffer, sizeof (buffer)) != 0 ? NULL : buffer;
+}