locale/programs/charmap-dir.c

   1 /* Copyright (C) 2000-2015 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published
   6    by the Free Software Foundation; version 2 of the License, or
   7    (at your option) any later version.
   8
   9    This program 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
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, see <http://www.gnu.org/licenses/>.  */
  16
  17 #include <dirent.h>
  18 #include <errno.h>
  19 #include <error.h>
  20 #include <fcntl.h>
  21 #include <libintl.h>
  22 #include <spawn.h>
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <unistd.h>
  27 #include <sys/stat.h>
  28
  29 #include "localedef.h"
  30 #include "charmap-dir.h"
  31
  32 /* The data type of a charmap directory being traversed.  */
  33 struct charmap_dir
  34 {
  35   DIR *dir;
  36   /* The directory pathname, ending in a slash.  */
  37   char *directory;
  38   size_t directory_len;
  39   /* Scratch area used for returning pathnames.  */
  40   char *pathname;
  41   size_t pathname_size;
  42 };
  43
  44 /* Starts a charmap directory traversal.
  45    Returns a CHARMAP_DIR, or NULL if the directory doesn't exist.  */
  46 CHARMAP_DIR *
  47 charmap_opendir (const char *directory)
  48 {
  49   struct charmap_dir *cdir;
  50   DIR *dir;
  51   size_t len;
  52   int add_slash;
  53
  54   dir = opendir (directory);
  55   if (dir == NULL)
  56     {
  57       WITH_CUR_LOCALE (error (1, errno, gettext ("\
  58 cannot read character map directory `%s'"), directory));
  59       return NULL;
  60     }
  61
  62   cdir = (struct charmap_dir *) xmalloc (sizeof (struct charmap_dir));
  63   cdir->dir = dir;
  64
  65   len = strlen (directory);
  66   add_slash = (len == 0 || directory[len - 1] != '/');
  67   cdir->directory = (char *) xmalloc (len + add_slash + 1);
  68   memcpy (cdir->directory, directory, len);
  69   if (add_slash)
  70     cdir->directory[len] = '/';
  71   cdir->directory[len + add_slash] = '\0';
  72   cdir->directory_len = len + add_slash;
  73
  74   cdir->pathname = NULL;
  75   cdir->pathname_size = 0;
  76
  77   return cdir;
  78 }
  79
  80 /* Reads the next directory entry.
  81    Returns its charmap name, or NULL if past the last entry or upon error.
  82    The storage returned may be overwritten by a later charmap_readdir
  83    call on the same CHARMAP_DIR.  */
  84 const char *
  85 charmap_readdir (CHARMAP_DIR *cdir)
  86 {
  87   for (;;)
  88     {
  89       struct dirent64 *dirent;
  90       size_t len;
  91       size_t size;
  92       char *filename;
  93       mode_t mode;
  94
  95       dirent = readdir64 (cdir->dir);
  96       if (dirent == NULL)
  97         return NULL;
  98       if (strcmp (dirent->d_name, ".") == 0)
  99         continue;
 100       if (strcmp (dirent->d_name, "..") == 0)
 101         continue;
 102
 103       len = strlen (dirent->d_name);
 104
 105       size = cdir->directory_len + len + 1;
 106       if (size > cdir->pathname_size)
 107         {
 108           free (cdir->pathname);
 109           if (size < 2 * cdir->pathname_size)
 110             size = 2 * cdir->pathname_size;
 111           cdir->pathname = (char *) xmalloc (size);
 112           cdir->pathname_size = size;
 113         }
 114
 115       stpcpy (stpcpy (cdir->pathname, cdir->directory), dirent->d_name);
 116       filename = cdir->pathname + cdir->directory_len;
 117
 118 #ifdef _DIRENT_HAVE_D_TYPE
 119       if (dirent->d_type != DT_UNKNOWN && dirent->d_type != DT_LNK)
 120         mode = DTTOIF (dirent->d_type);
 121       else
 122 #endif
 123         {
 124           struct stat64 statbuf;
 125
 126           if (stat64 (cdir->pathname, &statbuf) < 0)
 127             continue;
 128
 129           mode = statbuf.st_mode;
 130         }
 131
 132       if (!S_ISREG (mode))
 133         continue;
 134
 135       /* For compressed charmaps, the canonical charmap name does not
 136          include the extension.  */
 137       if (len > 3 && memcmp (&filename[len - 3], ".gz", 3) == 0)
 138         filename[len - 3] = '\0';
 139       else if (len > 4 && memcmp (&filename[len - 4], ".bz2", 4) == 0)
 140         filename[len - 4] = '\0';
 141
 142       return filename;
 143     }
 144 }
 145
 146 /* Finishes a charmap directory traversal, and frees the resources
 147    attached to the CHARMAP_DIR.  */
 148 int
 149 charmap_closedir (CHARMAP_DIR *cdir)
 150 {
 151   DIR *dir = cdir->dir;
 152
 153   free (cdir->directory);
 154   free (cdir->pathname);
 155   free (cdir);
 156   return closedir (dir);
 157 }
 158
 159 /* Creates a subprocess decompressing the given pathname, and returns
 160    a stream reading its output (the decompressed data).  */
 161 static
 162 FILE *
 163 fopen_uncompressed (const char *pathname, const char *compressor)
 164 {
 165   int pfd;
 166
 167   pfd = open (pathname, O_RDONLY);
 168   if (pfd >= 0)
 169     {
 170       struct stat64 statbuf;
 171       int fd[2];
 172
 173       if (fstat64 (pfd, &statbuf) >= 0
 174           && S_ISREG (statbuf.st_mode)
 175           && pipe (fd) >= 0)
 176         {
 177           char *argv[4]
 178             = { (char *) compressor, (char *) "-d", (char *) "-c", NULL };
 179           posix_spawn_file_actions_t actions;
 180
 181           if (posix_spawn_file_actions_init (&actions) == 0)
 182             {
 183               if (posix_spawn_file_actions_adddup2 (&actions,
 184                                                     fd[1], STDOUT_FILENO) == 0
 185                   && posix_spawn_file_actions_addclose (&actions, fd[1]) == 0
 186                   && posix_spawn_file_actions_addclose (&actions, fd[0]) == 0
 187                   && posix_spawn_file_actions_adddup2 (&actions,
 188                                                        pfd, STDIN_FILENO) == 0
 189                   && posix_spawn_file_actions_addclose (&actions, pfd) == 0
 190                   && posix_spawnp (NULL, compressor, &actions, NULL,
 191                                    argv, environ) == 0)
 192                 {
 193                   posix_spawn_file_actions_destroy (&actions);
 194                   close (fd[1]);
 195                   close (pfd);
 196                   return fdopen (fd[0], "r");
 197                 }
 198               posix_spawn_file_actions_destroy (&actions);
 199             }
 200           close (fd[1]);
 201           close (fd[0]);
 202         }
 203       close (pfd);
 204     }
 205   return NULL;
 206 }
 207
 208 /* Opens a charmap for reading, given its name (not an alias name).  */
 209 FILE *
 210 charmap_open (const char *directory, const char *name)
 211 {
 212   size_t dlen = strlen (directory);
 213   int add_slash = (dlen == 0 || directory[dlen - 1] != '/');
 214   size_t nlen = strlen (name);
 215   char *pathname;
 216   char *p;
 217   FILE *stream;
 218
 219   pathname = alloca (dlen + add_slash + nlen + 5);
 220   p = stpcpy (pathname, directory);
 221   if (add_slash)
 222     *p++ = '/';
 223   p = stpcpy (p, name);
 224
 225   stream = fopen (pathname, "rm");
 226   if (stream != NULL)
 227     return stream;
 228
 229   memcpy (p, ".gz", 4);
 230   stream = fopen_uncompressed (pathname, "gzip");
 231   if (stream != NULL)
 232     return stream;
 233
 234   memcpy (p, ".bz2", 5);
 235   stream = fopen_uncompressed (pathname, "bzip2");
 236   if (stream != NULL)
 237     return stream;
 238
 239   return NULL;
 240 }
 241
 242 /* An empty alias list.  Avoids the need to return NULL from
 243    charmap_aliases.  */
 244 static char *empty[1];
 245
 246 /* Returns a NULL terminated list of alias names of a charmap.  */
 247 char **
 248 charmap_aliases (const char *directory, const char *name)
 249 {
 250   FILE *stream;
 251   char **aliases;
 252   size_t naliases;
 253
 254   stream = charmap_open (directory, name);
 255   if (stream == NULL)
 256     return empty;
 257
 258   aliases = NULL;
 259   naliases = 0;
 260
 261   while (!feof (stream))
 262     {
 263       char *alias = NULL;
 264       char junk[BUFSIZ];
 265
 266       if (fscanf (stream, " <code_set_name> %ms", &alias) == 1
 267           || fscanf (stream, "%% alias %ms", &alias) == 1)
 268         {
 269           aliases = (char **) xrealloc (aliases,
 270                                         (naliases + 2) * sizeof (char *));
 271           aliases[naliases++] = alias;
 272         }
 273
 274       /* Read the rest of the line.  */
 275       if (fgets (junk, sizeof junk, stream) != NULL)
 276         {
 277           if (strstr (junk, "CHARMAP") != NULL)
 278             /* We cannot expect more aliases from now on.  */
 279             break;
 280
 281           while (strchr (junk, '\n') == NULL
 282                  && fgets (junk, sizeof junk, stream) != NULL)
 283             continue;
 284         }
 285     }
 286
 287   fclose (stream);
 288
 289   if (naliases == 0)
 290     return empty;
 291
 292   aliases[naliases] = NULL;
 293   return aliases;
 294 }
 295
 296 /* Frees an alias list returned by charmap_aliases.  */
 297 void
 298 charmap_free_aliases (char **aliases)
 299 {
 300   if (aliases != empty)
 301     {
 302       char **p;
 303
 304       for (p = aliases; *p; p++)
 305         free (*p);
 306
 307       free (aliases);
 308     }
 309 }