libutil/openpty.c

   1 /* Copyright (C) 1998, 1999, 2004 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Zack Weinberg <zack@rabi.phys.columbia.edu>, 1998.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <errno.h>
  21 #include <fcntl.h>
  22 #include <limits.h>
  23 #include <pty.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <termios.h>
  27 #include <unistd.h>
  28 #include <sys/types.h>
  29
  30 /* BCS: the following function is, IMO, overkill */
  31 #if 0
  32 /* Return the result of ptsname_r in the buffer pointed to by PTS,
  33    which should be of length BUF_LEN.  If it is too long to fit in
  34    this buffer, a sufficiently long buffer is allocated using malloc,
  35    and returned in PTS.  0 is returned upon success, -1 otherwise.  */
  36 static int
  37 pts_name (int fd, char **pts, size_t buf_len)
  38 {
  39   int rv;
  40   char *buf = *pts;
  41
  42   for (;;)
  43     {
  44       char *new_buf;
  45
  46       if (buf_len)
  47         {
  48           rv = ptsname_r (fd, buf, buf_len);
  49
  50           if (rv != 0 || memchr (buf, '\0', buf_len))
  51             /* We either got an error, or we succeeded and the
  52                returned name fit in the buffer.  */
  53             break;
  54
  55           /* Try again with a longer buffer.  */
  56           buf_len += buf_len;   /* Double it */
  57         }
  58       else
  59         /* No initial buffer; start out by mallocing one.  */
  60         buf_len = 128;          /* First time guess.  */
  61
  62       if (buf != *pts)
  63         /* We've already malloced another buffer at least once.  */
  64         new_buf = realloc (buf, buf_len);
  65       else
  66         new_buf = malloc (buf_len);
  67       if (! new_buf)
  68         {
  69           rv = -1;
  70           __set_errno (ENOMEM);
  71           break;
  72         }
  73       buf = new_buf;
  74     }
  75
  76   if (rv == 0)
  77     *pts = buf;         /* Return buffer to the user.  */
  78   else if (buf != *pts)
  79     free (buf);         /* Free what we malloced when returning an error.  */
  80
  81   return rv;
  82 }
  83 #endif
  84
  85 /* Create pseudo tty master slave pair and set terminal attributes
  86    according to TERMP and WINP.  Return handles for both ends in
  87    AMASTER and ASLAVE, and return the name of the slave end in NAME.  */
  88 libutil_hidden_proto(openpty)
  89 int
  90 openpty (int *amaster, int *aslave, char *name, struct termios *termp,
  91          struct winsize *winp)
  92 {
  93 #if 0
  94 #ifdef PATH_MAX
  95   char _buf[PATH_MAX];
  96 #else
  97   char _buf[512];
  98 #endif
  99   char *buf = _buf;
 100 #else
 101 #ifdef PATH_MAX
 102   char buf[PATH_MAX];
 103 #else
 104   char buf[512];
 105 #endif
 106 #endif
 107   int master, slave;
 108
 109   master = posix_openpt (O_RDWR);
 110   if (master == -1)
 111     return -1;
 112
 113   if (grantpt (master))
 114     goto fail;
 115
 116   if (unlockpt (master))
 117     goto fail;
 118
 119 #if 0
 120   if (pts_name (master, &buf, sizeof (_buf)))
 121 #else
 122   if (ptsname_r (master, buf, sizeof buf))
 123 #endif
 124     goto fail;
 125
 126   slave = open (buf, O_RDWR | O_NOCTTY);
 127   if (slave == -1)
 128     {
 129 #if 0
 130       if (buf != _buf)
 131         free (buf);
 132 #endif
 133       goto fail;
 134     }
 135
 136   /* XXX Should we ignore errors here?  */
 137   if(termp)
 138     tcsetattr (slave, TCSAFLUSH, termp);
 139   if (winp)
 140     ioctl (slave, TIOCSWINSZ, winp);
 141
 142   *amaster = master;
 143   *aslave = slave;
 144   if (name != NULL)
 145     strcpy (name, buf);
 146
 147 #if 0
 148   if (buf != _buf)
 149     free (buf);
 150 #endif
 151   return 0;
 152
 153  fail:
 154   close (master);
 155   return -1;
 156 }
 157 libutil_hidden_def(openpty)