summaryrefslogtreecommitdiff
path: root/lib/savedir.c
blob: b837414335c9ddfd7fffd2d41683d5393a1d9e2b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
/* savedir.c -- save the list of files in a directory in a string

   Copyright (C) 1990, 1997, 1998, 1999, 2000, 2001, 2003, 2004, 2005,
   2006 Free Software Foundation, Inc.

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

/* Written by David MacKenzie <djm@gnu.ai.mit.edu>. */

#include <config.h>

#include "savedir.h"

#include <sys/types.h>

#include <errno.h>

#include <dirent.h>
#ifndef _D_EXACT_NAMLEN
# define _D_EXACT_NAMLEN(dp)	strlen ((dp)->d_name)
#endif

#include <stddef.h>
#include <stdlib.h>
#include <string.h>

#include "openat.h"
#include "xalloc.h"

#ifndef NAME_SIZE_DEFAULT
# define NAME_SIZE_DEFAULT 512
#endif

/* The results of opendir() in this file are not used with dirfd and fchdir,
   therefore save some unnecessary work in fchdir.c.  */
#undef opendir
#undef closedir

/* Return a freshly allocated string containing the file names
   in directory DIRP, separated by '\0' characters;
   the end is marked by two '\0' characters in a row.
   Return NULL (setting errno) if DIRP cannot be read or closed.
   If DIRP is NULL, return NULL without affecting errno.  */

static char *
savedirstream (DIR *dirp)
{
  char *name_space;
  size_t allocated = NAME_SIZE_DEFAULT;
  size_t used = 0;
  int save_errno;

  if (dirp == NULL)
    return NULL;

  name_space = xmalloc (allocated);

  for (;;)
    {
      struct dirent const *dp;
      char const *entry;

      errno = 0;
      dp = readdir (dirp);
      if (! dp)
	break;

      /* Skip "", ".", and "..".  "" is returned by at least one buggy
         implementation: Solaris 2.4 readdir on NFS file systems.  */
      entry = dp->d_name;
      if (entry[entry[0] != '.' ? 0 : entry[1] != '.' ? 1 : 2] != '\0')
	{
	  size_t entry_size = _D_EXACT_NAMLEN (dp) + 1;
	  if (used + entry_size < used)
	    xalloc_die ();
	  if (allocated <= used + entry_size)
	    {
	      do
		{
		  if (2 * allocated < allocated)
		    xalloc_die ();
		  allocated *= 2;
		}
	      while (allocated <= used + entry_size);

	      name_space = xrealloc (name_space, allocated);
	    }
	  memcpy (name_space + used, entry, entry_size);
	  used += entry_size;
	}
    }
  name_space[used] = '\0';
  save_errno = errno;
  if (closedir (dirp) != 0)
    save_errno = errno;
  if (save_errno != 0)
    {
      free (name_space);
      errno = save_errno;
      return NULL;
    }
  return name_space;
}

/* Return a freshly allocated string containing the file names
   in directory DIR, separated by '\0' characters;
   the end is marked by two '\0' characters in a row.
   Return NULL (setting errno) if DIR cannot be opened, read, or closed.  */

char *
savedir (char const *dir)
{
  return savedirstream (opendir (dir));
}

/* Return a freshly allocated string containing the file names
   in directory FD, separated by '\0' characters;
   the end is marked by two '\0' characters in a row.
   Return NULL (setting errno) if FD cannot be read or closed.  */

char *
fdsavedir (int fd)
{
  return savedirstream (fdopendir (fd));
}