sysdeps/unix/opendir.c

   1 /* Copyright (C) 1991, 92, 93, 94, 95, 96 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
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, 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
  40   if (name[0] == '\0')
  41     {
  42       /* POSIX.1-1990 says an empty name gets ENOENT;
  43          but `open' might like it fine.  */
  44       errno = ENOENT;
  45       return NULL;
  46     }
  47
  48   fd = __open (name, O_RDONLY);
  49   if (fd < 0)
  50     return NULL;
  51
  52   if (fcntl (fd, F_SETFD, FD_CLOEXEC) < 0)
  53     goto lose;
  54
  55   if (fstat (fd, &statbuf) < 0)
  56     goto lose;
  57   if (! S_ISDIR (statbuf.st_mode))
  58     {
  59       errno = ENOTDIR;
  60       goto lose;
  61     }
  62
  63   dirp = (DIR *) calloc (1, sizeof (DIR)); /* Zero-fill.  */
  64   if (dirp == NULL)
  65   lose:
  66     {
  67       int save = errno;
  68       (void) __close (fd);
  69       errno = save;
  70       return NULL;
  71     }
  72
  73 #ifdef _STATBUF_ST_BLKSIZE
  74   if (statbuf.st_blksize < sizeof (struct dirent))
  75     dirp->allocation = sizeof (struct dirent);
  76   else
  77     dirp->allocation = statbuf.st_blksize;
  78 #else
  79   dirp->allocation = (BUFSIZ < sizeof (struct dirent) ?
  80                       sizeof (struct dirent) : BUFSIZ);
  81 #endif
  82   dirp->data = (char *) malloc (dirp->allocation);
  83   if (dirp->data == NULL)
  84     {
  85       int save = errno;
  86       free (dirp);
  87       (void) __close (fd);
  88       errno = save;
  89       return NULL;
  90     }
  91
  92   dirp->fd = fd;
  93
  94   __libc_lock_init (dirp->lock);
  95
  96   return dirp;
  97 }