sysdeps/unix/sysv/linux/ttyname_r.c

   1 /* Copyright (C) 1991, 92, 93, 95, 96, 97, 98 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 static int getttyname_r __P ((int fd, char *buf, size_t buflen,
  30                               dev_t mydev, ino_t myino, int save,
  31                               int *dostat)) internal_function;
  32
  33 static int
  34 internal_function
  35 getttyname_r (fd, buf, buflen, mydev, myino, save, dostat)
  36      int fd;
  37      char *buf;
  38      size_t buflen;
  39      dev_t mydev;
  40      ino_t myino;
  41      int save;
  42      int *dostat;
  43 {
  44   struct stat st;
  45   DIR *dirstream;
  46   struct dirent *d;
  47   size_t devlen = strlen (buf);
  48
  49   dirstream = __opendir (buf);
  50   if (dirstream == NULL)
  51     {
  52       *dostat = -1;
  53       return errno;
  54     }
  55
  56   while ((d = __readdir (dirstream)) != NULL)
  57     if (((ino_t) d->d_fileno == myino || *dostat)
  58         && strcmp (d->d_name, "stdin")
  59         && strcmp (d->d_name, "stdout")
  60         && strcmp (d->d_name, "stderr"))
  61       {
  62         char *cp;
  63         size_t needed = _D_EXACT_NAMLEN (d) + 1;
  64
  65         if (needed > buflen)
  66           {
  67             *dostat = -1;
  68             (void) __closedir (dirstream);
  69             __set_errno (ERANGE);
  70             return ERANGE;
  71           }
  72
  73         cp = __stpncpy (buf + devlen, d->d_name, needed);
  74         cp[0] = '\0';
  75
  76         if (stat (buf, &st) == 0
  77 #ifdef _STATBUF_ST_RDEV
  78             && S_ISCHR (st.st_mode) && st.st_rdev == mydev
  79 #else
  80             && (ino_t) d->d_fileno == myino && st.st_dev == mydev
  81 #endif
  82            )
  83           {
  84             (void) __closedir (dirstream);
  85             __set_errno (save);
  86             return 0;
  87           }
  88       }
  89
  90   (void) __closedir (dirstream);
  91   __set_errno (save);
  92   /* It is not clear what to return in this case.  `isatty' says FD
  93      refers to a TTY but no entry in /dev has this inode.  */
  94   return ENOTTY;
  95 }
  96
  97 /* Store at most BUFLEN character of the pathname of the terminal FD is
  98    open on in BUF.  Return 0 on success,  otherwise an error number.  */
  99 int
 100 __ttyname_r (fd, buf, buflen)
 101      int fd;
 102      char *buf;
 103      size_t buflen;
 104 {
 105   struct stat st, st1;
 106   int dostat = 0;
 107   int save = errno;
 108   int ret;
 109
 110   /* Test for the absolute minimal size.  This makes life easier inside
 111      the loop.  */
 112   if (!buf)
 113     {
 114       __set_errno (EINVAL);
 115       return EINVAL;
 116     }
 117
 118   if (buflen < sizeof ("/dev/pts/"))
 119     {
 120       __set_errno (ERANGE);
 121       return ERANGE;
 122     }
 123
 124   if (!__isatty (fd))
 125     {
 126       __set_errno (ENOTTY);
 127       return ENOTTY;
 128     }
 129
 130   if (fstat (fd, &st) < 0)
 131     return errno;
 132
 133   /* Prepare the result buffer.  */
 134   memcpy (buf, "/dev/pts/", sizeof ("/dev/pts/"));
 135   buflen -= sizeof ("/dev/pts/") - 1;
 136
 137   if (stat (buf, &st1) == 0 && S_ISDIR (st1.st_mode))
 138     {
 139 #ifdef _STATBUF_ST_RDEV
 140       ret = getttyname_r (fd, buf, buflen, st.st_rdev, st.st_ino, save,
 141                           &dostat);
 142 #else
 143       ret = getttyname_r (fd, buf, buflen, st.st_dev, st.st_ino, save,
 144                           &dostat);
 145 #endif
 146     }
 147   else
 148     {
 149       __set_errno (save);
 150       ret = ENOENT;
 151     }
 152
 153   if (ret && dostat != -1)
 154     {
 155       buf[sizeof ("/dev/") - 1] = '\0';
 156       buflen += sizeof ("pts/") - 1;
 157 #ifdef _STATBUF_ST_RDEV
 158       ret = getttyname_r (fd, buf, buflen, st.st_rdev, st.st_ino, save,
 159                           &dostat);
 160 #else
 161       ret = getttyname_r (fd, buf, buflen, st.st_dev, st.st_ino, save,
 162                           &dostat);
 163 #endif
 164     }
 165
 166   if (ret && dostat != -1)
 167     {
 168       buf[sizeof ("/dev/") - 1] = '\0';
 169       dostat = 1;
 170 #ifdef _STATBUF_ST_RDEV
 171       ret = getttyname_r (fd, buf, buflen, st.st_rdev, st.st_ino,
 172                           save, &dostat);
 173 #else
 174       ret = getttyname_r (fd, buf, buflen, st.st_dev, st.st_ino,
 175                           save, &dostat);
 176 #endif
 177     }
 178
 179   return ret;
 180 }
 181
 182 weak_alias (__ttyname_r, ttyname_r)