locale/programs/charmap-dir.c

   1 /* Copyright (C) 2000 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 not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #include <dirent.h>
  20 #include <errno.h>
  21 #include <error.h>
  22 #include <fcntl.h>
  23 #include <libintl.h>
  24 #include <spawn.h>
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <unistd.h>
  29 #include <sys/stat.h>
  30
  31 #include "charmap-dir.h"
  32
  33 extern void *xmalloc (size_t n);
  34 extern void *xrealloc (void *p, size_t n);
  35
  36 /* The data type of a charmap directory being traversed.  */
  37 struct charmap_dir
  38 {
  39   DIR *dir;
  40   /* The directory pathname, ending in a slash.  */
  41   char *directory;
  42   size_t directory_len;
  43   /* Scratch area used for returning pathnames.  */
  44   char *pathname;
  45   size_t pathname_size;
  46 };
  47
  48 /* Starts a charmap directory traversal.
  49    Returns a CHARMAP_DIR, or NULL if the directory doesn't exist.  */
  50 CHARMAP_DIR *
  51 charmap_opendir (const char *directory)
  52 {
  53   struct charmap_dir *cdir;
  54   DIR *dir;
  55   size_t len;
  56   int add_slash;
  57
  58   dir = opendir (directory);
  59   if (dir == NULL)
  60     {
  61       error (1, errno, gettext ("cannot read character map directory `%s'"),
  62              directory);
  63       return NULL;
  64     }
  65
  66   cdir = (struct charmap_dir *) xmalloc (sizeof (struct charmap_dir));
  67   cdir->dir = dir;
  68
  69   len = strlen (directory);
  70   add_slash = (len == 0 || directory[len - 1] != '/');
  71   cdir->directory = (char *) xmalloc (len + add_slash + 1);
  72   memcpy (cdir->directory, directory, len);
  73   if (add_slash)
  74     cdir->directory[len] = '/';
  75   cdir->directory[len + add_slash] = '\0';
  76   cdir->directory_len = len + add_slash;
  77
  78   cdir->pathname = NULL;
  79   cdir->pathname_size = 0;
  80
  81   return cdir;
  82 }
  83
  84 /* Reads the next directory entry.
  85    Returns its charmap name, or NULL if past the last entry or upon error.
  86    The storage returned may be overwritten by a later charmap_readdir
  87    call on the same CHARMAP_DIR.  */
  88 const char *
  89 charmap_readdir (CHARMAP_DIR *cdir)
  90 {
  91   for (;;)
  92     {
  93       struct dirent *dirent;
  94       size_t len;
  95       size_t size;
  96       char *filename;
  97       mode_t mode;
  98
  99       dirent = readdir (cdir->dir);
 100       if (dirent == NULL)
 101         return NULL;
 102       if (strcmp (dirent->d_name, ".") == 0)
 103         continue;
 104       if (strcmp (dirent->d_name, "..") == 0)
 105         continue;
 106
 107       len = strlen (dirent->d_name);
 108
 109       size = cdir->directory_len + len + 1;
 110       if (size > cdir->pathname_size)
 111         {
 112           free (cdir->pathname);
 113           if (size < 2 * cdir->pathname_size)
 114             size = 2 * cdir->pathname_size;
 115           cdir->pathname = (char *) xmalloc (size);
 116           cdir->pathname_size = size;
 117         }
 118
 119       stpcpy (stpcpy (cdir->pathname, cdir->directory), dirent->d_name);
 120       filename = cdir->pathname + cdir->directory_len;
 121
 122 #ifdef _DIRENT_HAVE_D_TYPE
 123       if (dirent->d_type != DT_UNKNOWN && dirent->d_type != DT_LNK)
 124         mode = DTTOIF (dirent->d_type);
 125       else
 126 #endif
 127         {
 128           struct stat statbuf;
 129
 130           if (stat (cdir->pathname, &statbuf) < 0)
 131             continue;
 132
 133           mode = statbuf.st_mode;
 134         }
 135
 136       if (!S_ISREG (mode))
 137         continue;
 138
 139       /* For compressed charmaps, the canonical charmap name does not
 140          include the extension.  */
 141       if (len > 3 && memcmp (&filename[len - 3], ".gz", 3) == 0)
 142         filename[len - 3] = '\0';
 143       else if (len > 4 && memcmp (&filename[len - 4], ".bz2", 4) == 0)
 144         filename[len - 4] = '\0';
 145
 146       return filename;
 147     }
 148 }
 149
 150 /* Finishes a charmap directory traversal, and frees the resources
 151    attached to the CHARMAP_DIR.  */
 152 int
 153 charmap_closedir (CHARMAP_DIR *cdir)
 154 {
 155   DIR *dir = cdir->dir;
 156
 157   free (cdir->directory);
 158   free (cdir->pathname);
 159   free (cdir);
 160   return closedir (dir);
 161 }
 162
 163 /* Creates a subprocess decompressing the given pathname, and returns
 164    a stream reading its output (the decompressed data).  */
 165 static
 166 FILE *
 167 fopen_uncompressed (const char *pathname, char *compressor)
 168 {
 169   int pfd;
 170
 171   pfd = open (pathname, O_RDONLY);
 172   if (pfd >= 0)
 173     {
 174       struct stat statbuf;
 175       int fd[2];
 176
 177       if (fstat (pfd, &statbuf) >= 0
 178           && S_ISREG (statbuf.st_mode)
 179           && pipe (fd) >= 0)
 180         {
 181           char *argv[4] = { compressor, "-d", "-c", NULL };
 182           posix_spawn_file_actions_t actions;
 183
 184           if (posix_spawn_file_actions_init (&actions) == 0)
 185             {
 186               if (posix_spawn_file_actions_adddup2 (&actions,
 187                                                     fd[1], STDOUT_FILENO) == 0
 188                   && posix_spawn_file_actions_addclose (&actions, fd[1]) == 0
 189                   && posix_spawn_file_actions_addclose (&actions, fd[0]) == 0
 190                   && posix_spawn_file_actions_adddup2 (&actions,
 191                                                        pfd, STDIN_FILENO) == 0
 192                   && posix_spawn_file_actions_addclose (&actions, pfd) == 0
 193                   && posix_spawnp (NULL, compressor, &actions, NULL,
 194                                    argv, environ) == 0)
 195                 {
 196                   posix_spawn_file_actions_destroy (&actions);
 197                   close (fd[1]);
 198                   close (pfd);
 199                   return fdopen (fd[0], "r");
 200                 }
 201               posix_spawn_file_actions_destroy (&actions);
 202             }
 203           close (fd[1]);
 204           close (fd[0]);
 205         }
 206       close (pfd);
 207     }
 208   return NULL;
 209 }
 210
 211 /* Opens a charmap for reading, given its name (not an alias name).  */
 212 FILE *
 213 charmap_open (const char *directory, const char *name)
 214 {
 215   size_t dlen = strlen (directory);
 216   int add_slash = (dlen == 0 || directory[dlen - 1] != '/');
 217   size_t nlen = strlen (name);
 218   char *pathname;
 219   char *p;
 220   FILE *stream;
 221
 222   pathname = alloca (dlen + add_slash + nlen + 5);
 223   p = stpcpy (pathname, directory);
 224   if (add_slash)
 225     *p++ = '/';
 226   p = stpcpy (p, name);
 227
 228   stream = fopen (pathname, "r");
 229   if (stream != NULL)
 230     return stream;
 231
 232   memcpy (p, ".gz", 4);
 233   stream = fopen_uncompressed (pathname, "gzip");
 234   if (stream != NULL)
 235     return stream;
 236
 237   memcpy (p, ".bz2", 5);
 238   stream = fopen_uncompressed (pathname, "bzip2");
 239   if (stream != NULL)
 240     return stream;
 241
 242   return NULL;
 243 }
 244
 245 /* An empty alias list.  Avoids the need to return NULL from
 246    charmap_aliases.  */
 247 static char *empty[1];
 248
 249 /* Returns a NULL terminated list of alias names of a charmap.  */
 250 char **
 251 charmap_aliases (const char *directory, const char *name)
 252 {
 253   FILE *stream;
 254   char **aliases;
 255   size_t naliases;
 256
 257   stream = charmap_open (directory, name);
 258   if (stream == NULL)
 259     return empty;
 260
 261   aliases = NULL;
 262   naliases = 0;
 263
 264   while (!feof (stream))
 265     {
 266       char *alias = NULL;
 267       char junk[BUFSIZ];
 268
 269       if (fscanf (stream, " <code_set_name> %as", &alias) == 1
 270           || fscanf (stream, "%% alias %as", &alias) == 1)
 271         {
 272           aliases = (char **) xrealloc (aliases,
 273                                         (naliases + 2) * sizeof (char *));
 274           aliases[naliases++] = alias;
 275         }
 276
 277       /* Read the rest of the line.  */
 278       if (fgets (junk, sizeof junk, stream) != NULL)
 279         {
 280           if (strstr (junk, "CHARMAP") != NULL)
 281             /* We cannot expect more aliases from now on.  */
 282             break;
 283
 284           while (strchr (junk, '\n') == NULL
 285                  && fgets (junk, sizeof junk, stream) != NULL)
 286             continue;
 287         }
 288     }
 289
 290   fclose (stream);
 291
 292   if (naliases == 0)
 293     return empty;
 294
 295   aliases[naliases] = NULL;
 296   return aliases;
 297 }
 298
 299 /* Frees an alias list returned by charmap_aliases.  */
 300 void
 301 charmap_free_aliases (char **aliases)
 302 {
 303   if (aliases != empty)
 304     {
 305       char **p;
 306
 307       for (p = aliases; *p; p++)
 308         free (*p);
 309
 310       free (aliases);
 311     }
 312 }