sysdeps/unix/opendir.c

   1 /* Copyright (C) 1991, 92, 93, 94, 95, 96, 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 <stdlib.h>
  23 #include <dirent.h>
  24 #include <fcntl.h>
  25 #include <sys/types.h>
  26 #include <sys/stat.h>
  27 #include <unistd.h>
  28 #include <stdio.h>
  29
  30 #include <dirstream.h>
  31
  32 /* Open a directory stream on NAME.  */
  33 DIR *
  34 __opendir (const char *name)
  35 {
  36   DIR *dirp;
  37   struct stat statbuf;
  38   int fd;
  39   size_t allocation;
  40   int save_errno;
  41
  42   if (name[0] == '\0')
  43     {
  44       /* POSIX.1-1990 says an empty name gets ENOENT;
  45          but `open' might like it fine.  */
  46       __set_errno (ENOENT);
  47       return NULL;
  48     }
  49
  50   fd = __open (name, O_RDONLY|O_NDELAY);
  51   if (fd < 0)
  52     return NULL;
  53
  54   if (__fcntl (fd, F_SETFD, FD_CLOEXEC) < 0)
  55     goto lose;
  56
  57   if (fstat (fd, &statbuf) < 0)
  58     goto lose;
  59   if (! S_ISDIR (statbuf.st_mode))
  60     {
  61       save_errno = ENOTDIR;
  62       goto lose2;
  63     }
  64
  65 #ifdef _STATBUF_ST_BLKSIZE
  66   if (statbuf.st_blksize < sizeof (struct dirent))
  67     allocation = sizeof (struct dirent);
  68   else
  69     allocation = statbuf.st_blksize;
  70 #else
  71   allocation = (BUFSIZ < sizeof (struct dirent)
  72                 ? sizeof (struct dirent) : BUFSIZ);
  73 #endif
  74
  75   dirp = (DIR *) calloc (1, sizeof (DIR) + allocation); /* Zero-fill.  */
  76   if (dirp == NULL)
  77   lose:
  78     {
  79       save_errno = errno;
  80     lose2:
  81       (void) __close (fd);
  82       __set_errno (save_errno);
  83       return NULL;
  84     }
  85   dirp->data = (char *) (dirp + 1);
  86   dirp->allocation = allocation;
  87   dirp->fd = fd;
  88
  89   __libc_lock_init (dirp->lock);
  90
  91   return dirp;
  92 }
  93 weak_alias (__opendir, opendir)