sysdeps/unix/sysv/linux/ttyname_r.c

   1 /* Copyright (C) 1991,92,93,1995-2001, 2003 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 Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the 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    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    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, ino64_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, ino64_t myino,
  38               int save, int *dostat)
  39 {
  40   struct stat64 st;
  41   DIR *dirstream;
  42   struct dirent64 *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 = __readdir64 (dirstream)) != NULL)
  53     if ((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 (__xstat64 (_STAT_VER, buf, &st) == 0
  73 #ifdef _STATBUF_ST_RDEV
  74             && S_ISCHR (st.st_mode) && st.st_rdev == mydev
  75 #else
  76             && 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 stat64 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   /* We try using the /proc filesystem.  */
 119   *_fitoa_word (fd, __stpcpy (procname, "/proc/self/fd/"), 10, 0) = '\0';
 120
 121   ret = __readlink (procname, buf, buflen - 1);
 122   if (ret == -1 && errno == ENOENT)
 123     {
 124       __set_errno (EBADF);
 125       return EBADF;
 126     }
 127
 128   if (!__isatty (fd))
 129     {
 130       __set_errno (ENOTTY);
 131       return ENOTTY;
 132     }
 133
 134   if (ret == -1 && errno == ENAMETOOLONG)
 135     {
 136       __set_errno (ERANGE);
 137       return ERANGE;
 138     }
 139
 140   if (ret != -1 && buf[0] != '[')
 141     {
 142       buf[ret] = '\0';
 143       return 0;
 144     }
 145
 146   if (__fxstat64 (_STAT_VER, fd, &st) < 0)
 147     return errno;
 148
 149   /* Prepare the result buffer.  */
 150   memcpy (buf, "/dev/pts/", sizeof ("/dev/pts/"));
 151   buflen -= sizeof ("/dev/pts/") - 1;
 152
 153   if (__xstat64 (_STAT_VER, buf, &st1) == 0 && S_ISDIR (st1.st_mode))
 154     {
 155 #ifdef _STATBUF_ST_RDEV
 156       ret = getttyname_r (buf, buflen, st.st_rdev, st.st_ino, save,
 157                           &dostat);
 158 #else
 159       ret = getttyname_r (buf, buflen, st.st_dev, st.st_ino, save,
 160                           &dostat);
 161 #endif
 162     }
 163   else
 164     {
 165       __set_errno (save);
 166       ret = ENOENT;
 167     }
 168
 169   if (ret && dostat != -1)
 170     {
 171       buf[sizeof ("/dev/") - 1] = '\0';
 172       buflen += sizeof ("pts/") - 1;
 173 #ifdef _STATBUF_ST_RDEV
 174       ret = getttyname_r (buf, buflen, st.st_rdev, st.st_ino, save,
 175                           &dostat);
 176 #else
 177       ret = getttyname_r (buf, buflen, st.st_dev, st.st_ino, save,
 178                           &dostat);
 179 #endif
 180     }
 181
 182   if (ret && dostat != -1)
 183     {
 184       buf[sizeof ("/dev/") - 1] = '\0';
 185       dostat = 1;
 186 #ifdef _STATBUF_ST_RDEV
 187       ret = getttyname_r (buf, buflen, st.st_rdev, st.st_ino,
 188                           save, &dostat);
 189 #else
 190       ret = getttyname_r (buf, buflen, st.st_dev, st.st_ino,
 191                           save, &dostat);
 192 #endif
 193     }
 194
 195   return ret;
 196 }
 197
 198 weak_alias (__ttyname_r, ttyname_r)