sysdeps/unix/sysv/linux/ttyname_r.c

   1 /* Copyright (C) 1991,92,93,95,96,97,98,99,2000 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    License, or (at your option) any later version.
   8
   9    The GNU C Library 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 GNU
  12    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #include <errno.h>
  20 #include <limits.h>
  21 #include <stddef.h>
  22 #include <dirent.h>
  23 #include <sys/types.h>
  24 #include <sys/stat.h>
  25 #include <unistd.h>
  26 #include <string.h>
  27 #include <stdlib.h>
  28
  29 #include <stdio-common/_itoa.h>
  30
  31 static int getttyname_r (char *buf, size_t buflen,
  32                          dev_t mydev, ino_t myino, int save,
  33                          int *dostat) internal_function;
  34
  35 static int
  36 internal_function
  37 getttyname_r (char *buf, size_t buflen, dev_t mydev, ino_t myino,
  38               int save, int *dostat)
  39 {
  40   struct stat st;
  41   DIR *dirstream;
  42   struct dirent *d;
  43   size_t devlen = strlen (buf);
  44
  45   dirstream = __opendir (buf);
  46   if (dirstream == NULL)
  47     {
  48       *dostat = -1;
  49       return errno;
  50     }
  51
  52   while ((d = __readdir (dirstream)) != NULL)
  53     if (((ino_t) d->d_fileno == myino || *dostat)
  54         && strcmp (d->d_name, "stdin")
  55         && strcmp (d->d_name, "stdout")
  56         && strcmp (d->d_name, "stderr"))
  57       {
  58         char *cp;
  59         size_t needed = _D_EXACT_NAMLEN (d) + 1;
  60
  61         if (needed > buflen)
  62           {
  63             *dostat = -1;
  64             (void) __closedir (dirstream);
  65             __set_errno (ERANGE);
  66             return ERANGE;
  67           }
  68
  69         cp = __stpncpy (buf + devlen, d->d_name, needed);
  70         cp[0] = '\0';
  71
  72         if (__xstat (_STAT_VER, buf, &st) == 0
  73 #ifdef _STATBUF_ST_RDEV
  74             && S_ISCHR (st.st_mode) && st.st_rdev == mydev
  75 #else
  76             && (ino_t) d->d_fileno == myino && st.st_dev == mydev
  77 #endif
  78            )
  79           {
  80             (void) __closedir (dirstream);
  81             __set_errno (save);
  82             return 0;
  83           }
  84       }
  85
  86   (void) __closedir (dirstream);
  87   __set_errno (save);
  88   /* It is not clear what to return in this case.  `isatty' says FD
  89      refers to a TTY but no entry in /dev has this inode.  */
  90   return ENOTTY;
  91 }
  92
  93 /* Store at most BUFLEN character of the pathname of the terminal FD is
  94    open on in BUF.  Return 0 on success,  otherwise an error number.  */
  95 int
  96 __ttyname_r (int fd, char *buf, size_t buflen)
  97 {
  98   char procname[30];
  99   struct stat st, st1;
 100   int dostat = 0;
 101   int save = errno;
 102   int ret;
 103
 104   /* Test for the absolute minimal size.  This makes life easier inside
 105      the loop.  */
 106   if (!buf)
 107     {
 108       __set_errno (EINVAL);
 109       return EINVAL;
 110     }
 111
 112   if (buflen < sizeof ("/dev/pts/"))
 113     {
 114       __set_errno (ERANGE);
 115       return ERANGE;
 116     }
 117
 118   if (!__isatty (fd))
 119     {
 120       __set_errno (ENOTTY);
 121       return ENOTTY;
 122     }
 123
 124   /* We try using the /proc filesystem.  */
 125   *_fitoa_word (fd, __stpcpy (procname, "/proc/self/fd/"), 10, 0) = '\0';
 126
 127   ret = __readlink (procname, buf, buflen - 1);
 128   if (ret != -1 && buf[0] != '[')
 129     {
 130       buf[ret] = '\0';
 131       return 0;
 132     }
 133   if (ret == -1 && errno == ENAMETOOLONG)
 134     {
 135       __set_errno (ERANGE);
 136       return ERANGE;
 137     }
 138
 139   if (__fxstat (_STAT_VER, fd, &st) < 0)
 140     return errno;
 141
 142   /* Prepare the result buffer.  */
 143   memcpy (buf, "/dev/pts/", sizeof ("/dev/pts/"));
 144   buflen -= sizeof ("/dev/pts/") - 1;
 145
 146   if (__xstat (_STAT_VER, buf, &st1) == 0 && S_ISDIR (st1.st_mode))
 147     {
 148 #ifdef _STATBUF_ST_RDEV
 149       ret = getttyname_r (buf, buflen, st.st_rdev, st.st_ino, save,
 150                           &dostat);
 151 #else
 152       ret = getttyname_r (buf, buflen, st.st_dev, st.st_ino, save,
 153                           &dostat);
 154 #endif
 155     }
 156   else
 157     {
 158       __set_errno (save);
 159       ret = ENOENT;
 160     }
 161
 162   if (ret && dostat != -1)
 163     {
 164       buf[sizeof ("/dev/") - 1] = '\0';
 165       buflen += sizeof ("pts/") - 1;
 166 #ifdef _STATBUF_ST_RDEV
 167       ret = getttyname_r (buf, buflen, st.st_rdev, st.st_ino, save,
 168                           &dostat);
 169 #else
 170       ret = getttyname_r (buf, buflen, st.st_dev, st.st_ino, save,
 171                           &dostat);
 172 #endif
 173     }
 174
 175   if (ret && dostat != -1)
 176     {
 177       buf[sizeof ("/dev/") - 1] = '\0';
 178       dostat = 1;
 179 #ifdef _STATBUF_ST_RDEV
 180       ret = getttyname_r (buf, buflen, st.st_rdev, st.st_ino,
 181                           save, &dostat);
 182 #else
 183       ret = getttyname_r (buf, buflen, st.st_dev, st.st_ino,
 184                           save, &dostat);
 185 #endif
 186     }
 187
 188   return ret;
 189 }
 190
 191 weak_alias (__ttyname_r, ttyname_r)