Add in libutil, based on Cory Visi's variant of Michael Shmulevich's libutil

port.  I have reworked the code quite a bit so that the stuff that is supposed
to be in libc is in libc, and I added a bunch of missing stuff so the libutil
interface matches that of glibc's libutil.  The only caveat is that
libutil/login.c is currently a stub.
 -Erik

8 files changed, 694 insertions, 1 deletions

diff --git a/libc/stdlib/Makefile b/libc/stdlib/Makefile
index 123841959..46276668b 100644
--- a/libc/stdlib/Makefile
+++ b/libc/stdlib/Makefile
@@ -38,7 +38,8 @@ MOBJ2=atexit.o exit.o
 
 
 CSRC =	abort.c getenv.c mktemp.c qsort.c realpath.c abs.c bsearch.c \
-	mkstemp.c putenv.c rand.c random.c setenv.c system.c div.c ldiv.c
+	mkstemp.c putenv.c rand.c random.c setenv.c system.c div.c ldiv.c \
+	getpt.c ptsname.c grantpt.c unlockpt.c
 ifeq ($(HAS_FLOATS),true)
 	CSRC += strtod.c
 endif
diff --git a/libc/stdlib/bsd_getpt.c b/libc/stdlib/bsd_getpt.c
new file mode 100644
index 000000000..0f981ab95
--- /dev/null
+++ b/libc/stdlib/bsd_getpt.c
@@ -0,0 +1,78 @@
+/* Copyright (C) 1998, 1999 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 <fcntl.h>
+#include <string.h>
+#include <unistd.h>
+
+
+/* Prefix for master pseudo terminal nodes.  */
+#define _PATH_PTY "/dev/pty"
+
+
+/* Letters indicating a series of pseudo terminals.  */
+#ifndef PTYNAME1
+#define PTYNAME1 "pqrsPQRS"
+#endif
+const char _ptyname1[] = PTYNAME1;
+
+/* Letters indicating the position within a series.  */
+#ifndef PTYNAME2
+#define PTYNAME2 "0123456789abcdefghijklmnopqrstuv";
+#endif
+const char _ptyname2[] = PTYNAME2;
+
+
+/* Open a master pseudo terminal and return its file descriptor.  */
+int
+__getpt (void)
+{
+  char buf[sizeof (_PATH_PTY) + 2];
+  const char *p, *q;
+  char *s;
+
+  memcpy (buf, _PATH_PTY, sizeof (_PATH_PTY) - 1);
+  s = buf + strlen (buf);
+
+  /* s[0] and s[1] will be filled in the loop.  */
+  s[2] = '\0';
+
+  for (p = _ptyname1; *p != '\0'; ++p)
+    {
+      s[0] = *p;
+
+      for (q = _ptyname2; *q != '\0'; ++q)
+	{
+	  int fd;
+
+	  s[1] = *q;
+
+	  fd = open (buf, O_RDWR);
+	  if (fd != -1)
+	    return fd;
+
+	  if (errno == ENOENT)
+	    return -1;
+	}
+    }
+
+  errno = ENOENT;
+  return -1;
+}
diff --git a/libc/stdlib/getpt.c b/libc/stdlib/getpt.c
new file mode 100644
index 000000000..74f009a95
--- /dev/null
+++ b/libc/stdlib/getpt.c
@@ -0,0 +1,89 @@
+/* Copyright (C) 1998, 1999 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 <fcntl.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <paths.h>
+#include <sys/statfs.h>
+
+/* Constant that identifies the `devpts' filesystem.  */
+#define DEVPTS_SUPER_MAGIC	0x1cd1
+/* Constant that identifies the `devfs' filesystem.  */
+#define DEVFS_SUPER_MAGIC	0x1373
+
+/* Path to the master pseudo terminal cloning device.  */
+#define _PATH_DEVPTMX _PATH_DEV "ptmx"
+/* Directory containing the UNIX98 pseudo terminals.  */
+#define _PATH_DEVPTS _PATH_DEV "pts"
+
+/* Prototype for function that opens BSD-style master pseudo-terminals.  */
+int __bsd_getpt (void);
+
+/* Open a master pseudo terminal and return its file descriptor.  */
+int
+getpt (void)
+{
+  static int have_no_dev_ptmx;
+  int fd;
+
+  if (!have_no_dev_ptmx)
+    {
+      fd = open (_PATH_DEVPTMX, O_RDWR);
+      if (fd != -1)
+	{
+	  struct statfs fsbuf;
+	  static int devpts_mounted;
+
+	  /* Check that the /dev/pts filesystem is mounted
+	     or if /dev is a devfs filesystem (this implies /dev/pts).  */
+	  if (devpts_mounted
+	      || (statfs (_PATH_DEVPTS, &fsbuf) == 0
+		  && fsbuf.f_type == DEVPTS_SUPER_MAGIC)
+	      || (statfs (_PATH_DEV, &fsbuf) == 0	
+		  && fsbuf.f_type == DEVFS_SUPER_MAGIC))
+	    {
+	      /* Everything is ok.  */
+	      devpts_mounted = 1;
+	      return fd;
+	    }
+
+	  /* If /dev/pts is not mounted then the UNIX98 pseudo terminals
+             are not usable.  */
+	  close (fd);
+	  have_no_dev_ptmx = 1;
+	}
+      else
+	{
+	  if (errno == ENOENT || errno == ENODEV)
+	    have_no_dev_ptmx = 1;
+	  else
+	    return -1;
+	}
+    }
+
+  return __bsd_getpt ();
+}
+
+#define PTYNAME1 "pqrstuvwxyzabcde";
+#define PTYNAME2 "0123456789abcdef";
+
+#define __getpt __bsd_getpt
+#include <bsd_getpt.c>
diff --git a/libc/stdlib/grantpt.c b/libc/stdlib/grantpt.c
new file mode 100644
index 000000000..63f423b8f
--- /dev/null
+++ b/libc/stdlib/grantpt.c
@@ -0,0 +1,66 @@
+/* Copyright (C) 1998, 1999 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 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 <limits.h>
+#include <stdlib.h>
+#include <sys/statfs.h>
+
+/* Constant that identifies the `devpts' filesystem.  */
+#define DEVPTS_SUPER_MAGIC	0x1cd1
+/* Constant that identifies the `devfs' filesystem.  */
+#define DEVFS_SUPER_MAGIC	0x1373
+
+/* Prototype for function that changes ownership and access permission
+   for slave pseudo terminals that do not live on a `devpts'
+   filesystem.  */
+int __unix_grantpt (int fd);
+
+/* Prototype for private function that gets the name of the slave
+   pseudo terminal in a safe way.  */
+static int pts_name (int fd, char **pts, size_t buf_len);
+
+/* Change the ownership and access permission of the slave pseudo
+   terminal associated with the master pseudo terminal specified
+   by FD.  */
+int
+grantpt (int fd)
+{
+  struct statfs fsbuf;
+#ifdef PATH_MAX
+  char _buf[PATH_MAX];
+#else
+  char _buf[512];
+#endif
+  char *buf = _buf;
+
+  if (pts_name (fd, &buf, sizeof (_buf)))
+    return -1;
+  
+  if (statfs (buf, &fsbuf) < 0)
+    return -1;
+
+  /* If the slave pseudo terminal lives on a `devpts' filesystem, the
+     ownership and access permission are already set.  */
+  if (fsbuf.f_type == DEVPTS_SUPER_MAGIC || fsbuf.f_type == DEVFS_SUPER_MAGIC)
+    return 0;
+
+  return __unix_grantpt (fd);
+}
+
+#define grantpt __unix_grantpt
+#include <unix_grantpt.c>
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;
+}
diff --git a/libc/stdlib/pty-private.h b/libc/stdlib/pty-private.h
new file mode 100644
index 000000000..621dbfd6f
--- /dev/null
+++ b/libc/stdlib/pty-private.h
@@ -0,0 +1,42 @@
+/* Internal defenitions and declarations for pseudo terminal functions.
+   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.  */
+
+#ifndef _PTY_PRIVATE_H
+#define _PTY_PRIVATE_H 1
+
+/* The group slave pseudo terminals belong to.  */
+#define TTY_GROUP "tty"
+
+/* The file descriptor connected to the master pseudo terminal.  */
+#define PTY_FILENO 3
+
+/* Path to the helper program that implements `grantpt' in user space.  */
+#define _PATH_PT_CHOWN "/sbin/pt_chown"
+
+/* Exit codes for the helper program.  */
+enum  /* failure modes */
+{
+  FAIL_EBADF = 1,
+  FAIL_EINVAL,
+  FAIL_EACCES,
+  FAIL_EXEC
+};
+
+#endif /* pty-private.h  */
diff --git a/libc/stdlib/unix_grantpt.c b/libc/stdlib/unix_grantpt.c
new file mode 100644
index 000000000..eb6ce0b35
--- /dev/null
+++ b/libc/stdlib/unix_grantpt.c
@@ -0,0 +1,197 @@
+/* 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 <assert.h>
+#include <errno.h>
+#include <grp.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/resource.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include "pty-private.h"
+
+extern int ptsname_r (int fd, char *buf, size_t buflen);
+
+/* Return the result of ptsname_r in the buffer pointed to by PTS,
+   which should be of length BUF_LEN.  If it is too long to fit in
+   this buffer, a sufficiently long buffer is allocated using malloc,
+   and returned in PTS.  0 is returned upon success, -1 otherwise.  */
+static int
+pts_name (int fd, char **pts, size_t buf_len)
+{
+  int rv;
+  char *buf = *pts;
+
+  for (;;)
+    {
+      char *new_buf;
+
+      if (buf_len)
+	{
+	  rv = ptsname_r (fd, buf, buf_len);
+
+	  if (rv != 0 || memchr (buf, '\0', buf_len))
+	    /* We either got an error, or we succeeded and the
+	       returned name fit in the buffer.  */
+	    break;
+
+	  /* Try again with a longer buffer.  */
+	  buf_len += buf_len;	/* Double it */
+	}
+      else
+	/* No initial buffer; start out by mallocing one.  */
+	buf_len = 128;		/* First time guess.  */
+
+      if (buf != *pts)
+	/* We've already malloced another buffer at least once.  */
+	new_buf = realloc (buf, buf_len);
+      else
+	new_buf = malloc (buf_len);
+      if (! new_buf)
+	{
+	  rv = -1;
+	  errno = ENOMEM;
+	  break;
+	}
+      buf = new_buf;
+    }
+
+  if (rv == 0)
+    *pts = buf;		/* Return buffer to the user.  */
+  else if (buf != *pts)
+    free (buf);		/* Free what we malloced when returning an error.  */
+
+  return rv;
+}
+
+/* Change the ownership and access permission of the slave pseudo
+   terminal associated with the master pseudo terminal specified
+   by FD.  */
+int
+grantpt (int fd)
+{
+  int retval = -1;
+#ifdef PATH_MAX
+  char _buf[PATH_MAX];
+#else
+  char _buf[512];
+#endif
+  char *buf = _buf;
+  struct stat st;
+  uid_t uid;
+  gid_t gid;
+  pid_t pid;
+
+  if (pts_name (fd, &buf, sizeof (_buf)))
+    return -1;
+
+  if (_xstat (_STAT_VER, buf, &st) < 0)
+    goto cleanup;
+
+  /* Make sure that we own the device.  */
+  uid = getuid ();
+  if (st.st_uid != uid)
+    {
+      if (chown (buf, uid, st.st_gid) < 0)
+	goto helper;
+    }
+
+  gid = getgid ();
+
+  /* Make sure the group of the device is that special group.  */
+  if (st.st_gid != gid)
+    {
+      if (chown (buf, uid, gid) < 0)
+	goto helper;
+    }
+
+  /* Make sure the permission mode is set to readable and writable by
+     the owner, and writable by the group.  */
+  if ((st.st_mode & ACCESSPERMS) != (S_IRUSR|S_IWUSR|S_IWGRP))
+    {
+      if (chmod (buf, S_IRUSR|S_IWUSR|S_IWGRP) < 0)
+	goto helper;
+    }
+
+  retval = 0;
+  goto cleanup;
+
+  /* We have to use the helper program.  */
+ helper:
+
+  pid = fork ();
+  if (pid == -1)
+    goto cleanup;
+  else if (pid == 0)
+    {
+      /* Disable core dumps.  */
+      struct rlimit rl = { 0, 0 };
+      setrlimit (RLIMIT_CORE, &rl);
+
+      /* We pase the master pseudo terminal as file descriptor PTY_FILENO.  */
+      if (fd != PTY_FILENO)
+	if (dup2 (fd, PTY_FILENO) < 0)
+	  exit (FAIL_EBADF);
+
+      execle (_PATH_PT_CHOWN, _PATH_PT_CHOWN, NULL, NULL);
+      exit (FAIL_EXEC);
+    }
+  else
+    {
+      int w;
+
+      if (waitpid (pid, &w, 0) == -1)
+	goto cleanup;
+      if (!WIFEXITED (w))
+	errno = ENOEXEC;
+      else
+	switch (WEXITSTATUS(w))
+	  {
+	  case 0:
+	    retval = 0;
+	    break;
+	  case FAIL_EBADF:
+	    errno = EBADF;
+	    break;
+	  case FAIL_EINVAL:
+	    errno = EINVAL;
+	    break;
+	  case FAIL_EACCES:
+	    errno = EACCES;
+	    break;
+	  case FAIL_EXEC:
+	    errno = ENOEXEC;
+	    break;
+
+	  default:
+	    assert(! "getpt: internal error: invalid exit code from pt_chown");
+	  }
+    }
+
+ cleanup:
+  if (buf != _buf)
+    free (buf);
+
+  return retval;
+}
diff --git a/libc/stdlib/unlockpt.c b/libc/stdlib/unlockpt.c
new file mode 100644
index 000000000..5dfea15d7
--- /dev/null
+++ b/libc/stdlib/unlockpt.c
@@ -0,0 +1,49 @@
+/* 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 <stdlib.h>
+#include <sys/ioctl.h>
+#include <termios.h>
+
+
+/* Unlock the slave pseudo terminal associated with the master pseudo
+   terminal specified by FD.  */
+int
+unlockpt (int fd)
+{
+#ifdef TIOCSPTLCK
+  int save_errno = errno;
+  int unlock = 0;
+
+  if (ioctl (fd, TIOCSPTLCK, &unlock))
+    {
+      if (errno == EINVAL)
+	{
+	  errno = save_errno;
+	  return 0;
+	}
+      else
+	return -1;
+    }
+#endif
+  /* If we have no TIOCSPTLCK ioctl, all slave pseudo terminals are
+     unlocked by default.  */
+  return 0;
+}