lib/ptsname_r.c

   1 /* Determine name of the slave side of a pseudo-terminal.
   2    Copyright (C) 1998, 2002, 2010-2017 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 #include <config.h>
  18
  19 #include <stdlib.h>
  20
  21 #include <errno.h>
  22 #include <fcntl.h>
  23 #include <string.h>
  24 #include <sys/stat.h>
  25 #include <unistd.h>
  26
  27 #ifdef _LIBC
  28 # include <paths.h>
  29 #else
  30 # ifndef _PATH_TTY
  31 #  define _PATH_TTY "/dev/tty"
  32 # endif
  33 # ifndef _PATH_DEV
  34 #  define _PATH_DEV "/dev/"
  35 # endif
  36
  37 # undef __set_errno
  38 # undef __stat
  39 # undef __ttyname_r
  40 # undef __ptsname_r
  41
  42 # define __set_errno(e) errno = (e)
  43 # define __isatty isatty
  44 # define __stat stat
  45 # define __ttyname_r ttyname_r
  46 # define __ptsname_r ptsname_r
  47
  48 #endif
  49
  50 /* Get the major, minor macros.  */
  51 #if MAJOR_IN_MKDEV
  52 # include <sys/mkdev.h>
  53 #endif
  54 #if MAJOR_IN_SYSMACROS
  55 # include <sys/sysmacros.h>
  56 #endif
  57
  58 #ifdef __sun
  59 /* Get ioctl() and 'struct strioctl'.  */
  60 # include <stropts.h>
  61 /* Get ISPTM.  */
  62 # include <sys/stream.h>
  63 # include <sys/ptms.h>
  64 # include <stdio.h>
  65 #endif
  66
  67 #if defined _AIX || defined __osf__
  68 /* Get ioctl(), ISPTM.  */
  69 # include <sys/ioctl.h>
  70 # include <stdio.h>
  71 #endif
  72
  73
  74 /* Store at most BUFLEN characters of the pathname of the slave pseudo
  75    terminal associated with the master FD is open on in BUF.
  76    Return 0 on success, otherwise an error number.  */
  77 int
  78 __ptsname_r (int fd, char *buf, size_t buflen)
  79 {
  80   int save_errno = errno;
  81   int err;
  82   struct stat st;
  83
  84   if (buf == NULL)
  85     {
  86       __set_errno (EINVAL);
  87       return EINVAL;
  88     }
  89
  90 #if defined __sun /* Solaris */
  91   if (fstat (fd, &st) < 0)
  92     return errno;
  93   if (!(S_ISCHR (st.st_mode) && major (st.st_rdev) == 0))
  94     {
  95       errno = ENOTTY;
  96       return errno;
  97     }
  98   {
  99     /* Master ptys can be recognized through a STREAMS ioctl.  See
 100        "STREAMS-based Pseudo-Terminal Subsystem"
 101        <http://docs.oracle.com/cd/E18752_01/html/816-4855/termsub15-44781.html>
 102        and "STREAMS ioctl commands"
 103        <http://docs.oracle.com/cd/E18752_01/html/816-5177/streamio-7i.html>
 104      */
 105     struct strioctl ioctl_arg;
 106     ioctl_arg.ic_cmd = ISPTM;
 107     ioctl_arg.ic_timout = 0;
 108     ioctl_arg.ic_len = 0;
 109     ioctl_arg.ic_dp = NULL;
 110
 111     if (ioctl (fd, I_STR, &ioctl_arg) < 0)
 112       {
 113         errno = ENOTTY;
 114         return errno;
 115       }
 116   }
 117   {
 118     char tmpbuf[9 + 10 + 1];
 119     int n = sprintf (tmpbuf, "/dev/pts/%u", minor (st.st_rdev));
 120     if (n >= buflen)
 121       {
 122         errno = ERANGE;
 123         return errno;
 124       }
 125     memcpy (buf, tmpbuf, n + 1);
 126   }
 127 #elif defined _AIX || defined __osf__ /* AIX, OSF/1 */
 128   /* This implementation returns /dev/pts/N, like ptsname() does.
 129      Whereas the generic implementation below returns /dev/ttypN.
 130      Both are correct, but let's be consistent with ptsname().  */
 131   if (fstat (fd, &st) < 0)
 132     return errno;
 133   if (!S_ISCHR (st.st_mode))
 134     {
 135       errno = ENOTTY;
 136       return errno;
 137     }
 138   {
 139     int ret;
 140     int dev;
 141     char tmpbuf[9 + 10 + 1];
 142     int n;
 143 # ifdef _AIX
 144     ret = ioctl (fd, ISPTM, &dev);
 145 # endif
 146 # ifdef __osf__
 147     ret = ioctl (fd, ISPTM, NULL);
 148     dev = ret;
 149 # endif
 150     if (ret < 0)
 151       {
 152         errno = ENOTTY;
 153         return errno;
 154       }
 155     n = sprintf (tmpbuf, "/dev/pts/%u", minor (dev));
 156     if (n >= buflen)
 157       {
 158         errno = ERANGE;
 159         return errno;
 160       }
 161     memcpy (buf, tmpbuf, n + 1);
 162   }
 163 #else
 164   if (!__isatty (fd))
 165     {
 166 #if ISATTY_FAILS_WITHOUT_SETTING_ERRNO && defined F_GETFL /* IRIX, Solaris */
 167       /* Set errno.  */
 168       if (fcntl (fd, F_GETFL) != -1)
 169         errno = ENOTTY;
 170 #else
 171       /* We rely on isatty to set errno properly (i.e. EBADF or ENOTTY).  */
 172 #endif
 173       return errno;
 174     }
 175
 176   if (buflen < strlen (_PATH_TTY) + 3)
 177     {
 178       __set_errno (ERANGE);
 179       return ERANGE;
 180     }
 181
 182   err = __ttyname_r (fd, buf, buflen);
 183   if (err != 0)
 184     {
 185       __set_errno (err);
 186       return errno;
 187     }
 188
 189   if (strncmp(buf, "/dev/pts/", strlen("/dev/pts/")) != 0)
 190     buf[sizeof (_PATH_DEV) - 1] = 't';
 191 #endif
 192
 193   if (__stat (buf, &st) < 0)
 194     return errno;
 195
 196   __set_errno (save_errno);
 197   return 0;
 198 }