summary refs log tree commit diff
path: root/locale/programs/charmap-dir.c
blob: 99fcd355e0f6799605a56467e50713d536f2177d (plain) (blame)
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
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
/* Copyright (C) 2000-2016 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   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; version 2 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/>.  */

#include <dirent.h>
#include <errno.h>
#include <error.h>
#include <fcntl.h>
#include <libintl.h>
#include <spawn.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>

#include "localedef.h"
#include "charmap-dir.h"

/* The data type of a charmap directory being traversed.  */
struct charmap_dir
{
  DIR *dir;
  /* The directory pathname, ending in a slash.  */
  char *directory;
  size_t directory_len;
  /* Scratch area used for returning pathnames.  */
  char *pathname;
  size_t pathname_size;
};

/* Starts a charmap directory traversal.
   Returns a CHARMAP_DIR, or NULL if the directory doesn't exist.  */
CHARMAP_DIR *
charmap_opendir (const char *directory)
{
  struct charmap_dir *cdir;
  DIR *dir;
  size_t len;
  int add_slash;

  dir = opendir (directory);
  if (dir == NULL)
    {
      WITH_CUR_LOCALE (error (1, errno, gettext ("\
cannot read character map directory `%s'"), directory));
      return NULL;
    }

  cdir = (struct charmap_dir *) xmalloc (sizeof (struct charmap_dir));
  cdir->dir = dir;

  len = strlen (directory);
  add_slash = (len == 0 || directory[len - 1] != '/');
  cdir->directory = (char *) xmalloc (len + add_slash + 1);
  memcpy (cdir->directory, directory, len);
  if (add_slash)
    cdir->directory[len] = '/';
  cdir->directory[len + add_slash] = '\0';
  cdir->directory_len = len + add_slash;

  cdir->pathname = NULL;
  cdir->pathname_size = 0;

  return cdir;
}

/* Reads the next directory entry.
   Returns its charmap name, or NULL if past the last entry or upon error.
   The storage returned may be overwritten by a later charmap_readdir
   call on the same CHARMAP_DIR.  */
const char *
charmap_readdir (CHARMAP_DIR *cdir)
{
  for (;;)
    {
      struct dirent64 *dirent;
      size_t len;
      size_t size;
      char *filename;
      mode_t mode;

      dirent = readdir64 (cdir->dir);
      if (dirent == NULL)
        return NULL;
      if (strcmp (dirent->d_name, ".") == 0)
        continue;
      if (strcmp (dirent->d_name, "..") == 0)
        continue;

      len = strlen (dirent->d_name);

      size = cdir->directory_len + len + 1;
      if (size > cdir->pathname_size)
        {
          free (cdir->pathname);
          if (size < 2 * cdir->pathname_size)
            size = 2 * cdir->pathname_size;
          cdir->pathname = (char *) xmalloc (size);
          cdir->pathname_size = size;
        }

      stpcpy (stpcpy (cdir->pathname, cdir->directory), dirent->d_name);
      filename = cdir->pathname + cdir->directory_len;

#ifdef _DIRENT_HAVE_D_TYPE
      if (dirent->d_type != DT_UNKNOWN && dirent->d_type != DT_LNK)
        mode = DTTOIF (dirent->d_type);
      else
#endif
        {
          struct stat64 statbuf;

          if (stat64 (cdir->pathname, &statbuf) < 0)
            continue;

          mode = statbuf.st_mode;
        }

      if (!S_ISREG (mode))
        continue;

      /* For compressed charmaps, the canonical charmap name does not
         include the extension.  */
      if (len > 3 && memcmp (&filename[len - 3], ".gz", 3) == 0)
        filename[len - 3] = '\0';
      else if (len > 4 && memcmp (&filename[len - 4], ".bz2", 4) == 0)
        filename[len - 4] = '\0';

      return filename;
    }
}

/* Finishes a charmap directory traversal, and frees the resources
   attached to the CHARMAP_DIR.  */
int
charmap_closedir (CHARMAP_DIR *cdir)
{
  DIR *dir = cdir->dir;

  free (cdir->directory);
  free (cdir->pathname);
  free (cdir);
  return closedir (dir);
}

/* Creates a subprocess decompressing the given pathname, and returns
   a stream reading its output (the decompressed data).  */
static
FILE *
fopen_uncompressed (const char *pathname, const char *compressor)
{
  int pfd;

  pfd = open (pathname, O_RDONLY);
  if (pfd >= 0)
    {
      struct stat64 statbuf;
      int fd[2];

      if (fstat64 (pfd, &statbuf) >= 0
          && S_ISREG (statbuf.st_mode)
          && pipe (fd) >= 0)
        {
          char *argv[4]
	    = { (char *) compressor, (char *) "-d", (char *) "-c", NULL };
          posix_spawn_file_actions_t actions;

          if (posix_spawn_file_actions_init (&actions) == 0)
            {
              if (posix_spawn_file_actions_adddup2 (&actions,
                                                    fd[1], STDOUT_FILENO) == 0
                  && posix_spawn_file_actions_addclose (&actions, fd[1]) == 0
                  && posix_spawn_file_actions_addclose (&actions, fd[0]) == 0
                  && posix_spawn_file_actions_adddup2 (&actions,
                                                       pfd, STDIN_FILENO) == 0
                  && posix_spawn_file_actions_addclose (&actions, pfd) == 0
                  && posix_spawnp (NULL, compressor, &actions, NULL,
                                   argv, environ) == 0)
                {
                  posix_spawn_file_actions_destroy (&actions);
                  close (fd[1]);
                  close (pfd);
                  return fdopen (fd[0], "r");
                }
              posix_spawn_file_actions_destroy (&actions);
            }
          close (fd[1]);
          close (fd[0]);
        }
      close (pfd);
    }
  return NULL;
}

/* Opens a charmap for reading, given its name (not an alias name).  */
FILE *
charmap_open (const char *directory, const char *name)
{
  size_t dlen = strlen (directory);
  int add_slash = (dlen == 0 || directory[dlen - 1] != '/');
  size_t nlen = strlen (name);
  char *pathname;
  char *p;
  FILE *stream;

  pathname = alloca (dlen + add_slash + nlen + 5);
  p = stpcpy (pathname, directory);
  if (add_slash)
    *p++ = '/';
  p = stpcpy (p, name);

  stream = fopen (pathname, "rm");
  if (stream != NULL)
    return stream;

  memcpy (p, ".gz", 4);
  stream = fopen_uncompressed (pathname, "gzip");
  if (stream != NULL)
    return stream;

  memcpy (p, ".bz2", 5);
  stream = fopen_uncompressed (pathname, "bzip2");
  if (stream != NULL)
    return stream;

  return NULL;
}

/* An empty alias list.  Avoids the need to return NULL from
   charmap_aliases.  */
static char *empty[1];

/* Returns a NULL terminated list of alias names of a charmap.  */
char **
charmap_aliases (const char *directory, const char *name)
{
  FILE *stream;
  char **aliases;
  size_t naliases;

  stream = charmap_open (directory, name);
  if (stream == NULL)
    return empty;

  aliases = NULL;
  naliases = 0;

  while (!feof (stream))
    {
      char *alias = NULL;
      char junk[BUFSIZ];

      if (fscanf (stream, " <code_set_name> %ms", &alias) == 1
          || fscanf (stream, "%% alias %ms", &alias) == 1)
        {
          aliases = (char **) xrealloc (aliases,
                                        (naliases + 2) * sizeof (char *));
          aliases[naliases++] = alias;
        }

      /* Read the rest of the line.  */
      if (fgets (junk, sizeof junk, stream) != NULL)
        {
          if (strstr (junk, "CHARMAP") != NULL)
            /* We cannot expect more aliases from now on.  */
            break;

          while (strchr (junk, '\n') == NULL
                 && fgets (junk, sizeof junk, stream) != NULL)
            continue;
        }
    }

  fclose (stream);

  if (naliases == 0)
    return empty;

  aliases[naliases] = NULL;
  return aliases;
}

/* Frees an alias list returned by charmap_aliases.  */
void
charmap_free_aliases (char **aliases)
{
  if (aliases != empty)
    {
      char **p;

      for (p = aliases; *p; p++)
        free (*p);

      free (aliases);
    }
}