sysdeps/unix/opendir.c

   1 /* Copyright (C) 1991, 1992, 1993, 1994 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
  33 /* Open a directory stream on NAME.  */
  34 DIR *
  35 DEFUN(opendir, (name), CONST char *name)
  36 {
  37   DIR *dirp;
  38   struct stat statbuf;
  39   int fd;
  40
  41   if (name[0] == '\0')
  42     {
  43       /* POSIX.1-1990 says an empty name gets ENOENT;
  44          but `open' might like it fine.  */
  45       errno = ENOENT;
  46       return NULL;
  47     }
  48
  49   fd = __open (name, O_RDONLY);
  50   if (fd < 0)
  51     return NULL;
  52
  53   if (fcntl (fd, F_SETFD, FD_CLOEXEC) < 0)
  54     goto lose;
  55
  56   if (fstat (fd, &statbuf) < 0)
  57     goto lose;
  58   if (! S_ISDIR (statbuf.st_mode))
  59     {
  60       errno = ENOTDIR;
  61       goto lose;
  62     }
  63
  64   dirp = (DIR *) calloc (1, sizeof (DIR) + NAME_MAX); /* Zero-fill.  */
  65   if (dirp == NULL)
  66   lose:
  67     {
  68       int save = errno;
  69       (void) __close (fd);
  70       errno = save;
  71       return NULL;
  72     }
  73
  74 #ifdef _STATBUF_ST_BLKSIZE
  75   if (statbuf.st_blksize < sizeof (struct direct))
  76     dirp->__allocation = sizeof (struct direct);
  77   else
  78     dirp->__allocation = statbuf.st_blksize;
  79 #else
  80   dirp->__allocation = (BUFSIZ < sizeof (struct direct) ?
  81                         sizeof (struct direct) : BUFSIZ);
  82 #endif
  83   dirp->__data = (char *) malloc (dirp->__allocation);
  84   if (dirp->__data == NULL)
  85     {
  86       int save = errno;
  87       free ((PTR) dirp);
  88       (void) __close (fd);
  89       errno = save;
  90       return NULL;
  91     }
  92
  93   dirp->__fd = fd;
  94   return dirp;
  95 }