sysdeps/unix/opendir.c

   1 /* Copyright (C) 1991, 1992, 1993, 1994, 1995 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 <ansidecl.h>
  20 #include <errno.h>
  21 #include <limits.h>
  22 #include <stddef.h>
  23 #include <stdlib.h>
  24 #include <dirent.h>
  25 #include <fcntl.h>
  26 #include <sys/types.h>
  27 #include <sys/stat.h>
  28 #include <unistd.h>
  29 #include <stdio.h>
  30
  31 #include "direct.h"             /* This file defines `struct direct'.  */
  32 #include "dirstream.h"
  33
  34 /* Open a directory stream on NAME.  */
  35 DIR *
  36 DEFUN(opendir, (name), CONST char *name)
  37 {
  38   DIR *dirp;
  39   struct stat statbuf;
  40   int fd;
  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       errno = ENOENT;
  47       return NULL;
  48     }
  49
  50   fd = __open (name, O_RDONLY);
  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       errno = ENOTDIR;
  62       goto lose;
  63     }
  64
  65   dirp = (DIR *) calloc (1, sizeof (DIR) + NAME_MAX); /* Zero-fill.  */
  66   if (dirp == NULL)
  67   lose:
  68     {
  69       int save = errno;
  70       (void) __close (fd);
  71       errno = save;
  72       return NULL;
  73     }
  74
  75 #ifdef _STATBUF_ST_BLKSIZE
  76   if (statbuf.st_blksize < sizeof (struct direct))
  77     dirp->__allocation = sizeof (struct direct);
  78   else
  79     dirp->__allocation = statbuf.st_blksize;
  80 #else
  81   dirp->__allocation = (BUFSIZ < sizeof (struct direct) ?
  82                         sizeof (struct direct) : BUFSIZ);
  83 #endif
  84   dirp->__data = (char *) malloc (dirp->__allocation);
  85   if (dirp->__data == NULL)
  86     {
  87       int save = errno;
  88       free ((PTR) dirp);
  89       (void) __close (fd);
  90       errno = save;
  91       return NULL;
  92     }
  93
  94   dirp->__fd = fd;
  95   return dirp;
  96 }