catgets/open_catalog.c

   1 /* Copyright (C) 1996, 1997, 1998 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper, <drepper@gnu.ai.mit.edu>.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include <byteswap.h>
  21 #include <endian.h>
  22 #include <errno.h>
  23 #include <fcntl.h>
  24 #include <string.h>
  25 #include <stdlib.h>
  26 #include <unistd.h>
  27 #ifdef _POSIX_MAPPED_FILES
  28 # include <sys/mman.h>
  29 #endif
  30 #include <sys/stat.h>
  31
  32 #include "catgetsinfo.h"
  33
  34
  35 #define SWAPU32(w) bswap_32 (w)
  36
  37
  38 void
  39 __open_catalog (__nl_catd catalog)
  40 {
  41   int fd = -1;
  42   struct stat st;
  43   int swapping;
  44   size_t cnt;
  45   size_t max_offset;
  46   size_t tab_size;
  47   const char *lastp;
  48
  49   /* Make sure we are alone.  */
  50   __libc_lock_lock (catalog->lock);
  51
  52   /* Check whether there was no other thread faster.  */
  53   if (catalog->status != closed)
  54     /* While we waited some other thread tried to open the catalog.  */
  55     goto unlock_return;
  56
  57   if (strchr (catalog->cat_name, '/') != NULL || catalog->nlspath == NULL)
  58     fd = __open (catalog->cat_name, O_RDONLY);
  59   else
  60     {
  61       const char *run_nlspath = catalog->nlspath;
  62 #define ENOUGH(n)                                                             \
  63   if (bufact + (n) >=bufmax)                                                  \
  64     {                                                                         \
  65       char *old_buf = buf;                                                    \
  66       bufmax += 256 + (n);                                                    \
  67       buf = (char *) alloca (bufmax);                                         \
  68       memcpy (buf, old_buf, bufact);                                          \
  69     }
  70
  71       /* The RUN_NLSPATH variable contains a colon separated list of
  72          descriptions where we expect to find catalogs.  We have to
  73          recognize certain % substitutions and stop when we found the
  74          first existing file.  */
  75       char *buf;
  76       size_t bufact;
  77       size_t bufmax;
  78       size_t len;
  79
  80       buf = NULL;
  81       bufmax = 0;
  82
  83       fd = -1;
  84       while (*run_nlspath != '\0')
  85         {
  86           bufact = 0;
  87           while (*run_nlspath != ':' && *run_nlspath != '\0')
  88             if (*run_nlspath == '%')
  89               {
  90                 const char *tmp;
  91
  92                 ++run_nlspath;  /* We have seen the `%'.  */
  93                 switch (*run_nlspath++)
  94                   {
  95                   case 'N':
  96                     /* Use the catalog name.  */
  97                     len = strlen (catalog->cat_name);
  98                     ENOUGH (len);
  99                     memcpy (&buf[bufact], catalog->cat_name, len);
 100                     bufact += len;
 101                     break;
 102                   case 'L':
 103                     /* Use the current locale category value.  */
 104                     len = strlen (catalog->env_var);
 105                     ENOUGH (len);
 106                     memcpy (&buf[bufact], catalog->env_var, len);
 107                     bufact += len;
 108                     break;
 109                   case 'l':
 110                     /* Use language element of locale category value.  */
 111                     tmp = catalog->env_var;
 112                     do
 113                       {
 114                         ENOUGH (1);
 115                         buf[bufact++] = *tmp++;
 116                       }
 117                     while (*tmp != '\0' && *tmp != '_' && *tmp != '.');
 118                     break;
 119                   case 't':
 120                     /* Use territory element of locale category value.  */
 121                     tmp = catalog->env_var;
 122                     do
 123                       ++tmp;
 124                     while (*tmp != '\0' && *tmp != '_' && *tmp != '.');
 125                     if (*tmp == '_')
 126                       {
 127                         ++tmp;
 128                         do
 129                           {
 130                             ENOUGH (1);
 131                             buf[bufact++] = *tmp;
 132                           }
 133                         while (*tmp != '\0' && *tmp != '.');
 134                       }
 135                     break;
 136                   case 'c':
 137                     /* Use code set element of locale category value.  */
 138                     tmp = catalog->env_var;
 139                     do
 140                       ++tmp;
 141                     while (*tmp != '\0' && *tmp != '.');
 142                     if (*tmp == '.')
 143                       {
 144                         ++tmp;
 145                         do
 146                           {
 147                             ENOUGH (1);
 148                             buf[bufact++] = *tmp;
 149                           }
 150                         while (*tmp != '\0');
 151                       }
 152                     break;
 153                   case '%':
 154                     ENOUGH (1);
 155                     buf[bufact++] = '%';
 156                     break;
 157                   default:
 158                     /* Unknown variable: ignore this path element.  */
 159                     bufact = 0;
 160                     while (*run_nlspath != '\0' && *run_nlspath != ':')
 161                       ++run_nlspath;
 162                     break;
 163                   }
 164               }
 165             else
 166               {
 167                 ENOUGH (1);
 168                 buf[bufact++] = *run_nlspath++;
 169               }
 170           ENOUGH (1);
 171           buf[bufact] = '\0';
 172
 173           if (bufact != 0)
 174             {
 175               fd = __open (buf, O_RDONLY);
 176               if (fd >= 0)
 177                 break;
 178             }
 179
 180           ++run_nlspath;
 181         }
 182     }
 183
 184   /* Avoid dealing with directories and block devices */
 185   if (fd < 0 || __fstat (fd, &st) < 0)
 186     {
 187       catalog->status = nonexisting;
 188       goto unlock_return;
 189     }
 190   if (!S_ISREG (st.st_mode) || st.st_size < sizeof (struct catalog_obj))
 191     {
 192       /* `errno' is not set correctly but the file is not usable.
 193          Use an reasonable error value.  */
 194       __set_errno (EINVAL);
 195       catalog->status = nonexisting;
 196       goto unlock_return;
 197     }
 198
 199   catalog->file_size = st.st_size;
 200 #ifdef _POSIX_MAPPED_FILES
 201 # ifndef MAP_COPY
 202     /* Linux seems to lack read-only copy-on-write.  */
 203 #  define MAP_COPY MAP_PRIVATE
 204 # endif
 205 # ifndef MAP_FILE
 206     /* Some systems do not have this flag; it is superfluous.  */
 207 #  define MAP_FILE 0
 208 # endif
 209 # ifndef MAP_INHERIT
 210     /* Some systems might lack this; they lose.  */
 211 #  define MAP_INHERIT 0
 212 # endif
 213   catalog->file_ptr =
 214     (struct catalog_obj *) __mmap (NULL, st.st_size, PROT_READ,
 215                                    MAP_FILE|MAP_COPY|MAP_INHERIT, fd, 0);
 216   if (catalog->file_ptr != (struct catalog_obj *) MAP_FAILED)
 217     /* Tell the world we managed to mmap the file.  */
 218     catalog->status = mmapped;
 219   else
 220 #endif /* _POSIX_MAPPED_FILES */
 221     {
 222       /* mmap failed perhaps because the system call is not
 223          implemented.  Try to load the file.  */
 224       size_t todo;
 225       catalog->file_ptr = malloc (st.st_size);
 226       if (catalog->file_ptr == NULL)
 227         {
 228           catalog->status = nonexisting;
 229           goto unlock_return;
 230         }
 231       todo = st.st_size;
 232       /* Save read, handle partial reads.  */
 233       do
 234         {
 235           size_t now = __read (fd, (((char *) &catalog->file_ptr)
 236                                     + (st.st_size - todo)), todo);
 237           if (now == 0)
 238             {
 239               free ((void *) catalog->file_ptr);
 240               catalog->status = nonexisting;
 241               goto unlock_return;
 242             }
 243           todo -= now;
 244         }
 245       while (todo > 0);
 246       catalog->status = malloced;
 247     }
 248
 249   /* We don't need the file anymore.  */
 250   __close (fd);
 251   fd = -1;
 252
 253   /* Determine whether the file is a catalog file and if yes whether
 254      it is written using the correct byte order.  Else we have to swap
 255      the values.  */
 256   if (catalog->file_ptr->magic == CATGETS_MAGIC)
 257     swapping = 0;
 258   else if (catalog->file_ptr->magic == SWAPU32 (CATGETS_MAGIC))
 259     swapping = 1;
 260   else
 261     {
 262     invalid_file:
 263       /* Invalid file.  Free the resources and mark catalog as not
 264          usable.  */
 265 #ifdef _POSIX_MAPPED_FILES
 266       if (catalog->status == mmapped)
 267         __munmap ((void *) catalog->file_ptr, catalog->file_size);
 268       else
 269 #endif  /* _POSIX_MAPPED_FILES */
 270         free (catalog->file_ptr);
 271       catalog->status = nonexisting;
 272       goto unlock_return;
 273     }
 274
 275 #define SWAP(x) (swapping ? SWAPU32 (x) : (x))
 276
 277   /* Get dimensions of the used hashing table.  */
 278   catalog->plane_size = SWAP (catalog->file_ptr->plane_size);
 279   catalog->plane_depth = SWAP (catalog->file_ptr->plane_depth);
 280
 281   /* The file contains two versions of the pointer tables.  Pick the
 282      right one for the local byte order.  */
 283 #if __BYTE_ORDER == __LITTLE_ENDIAN
 284   catalog->name_ptr = &catalog->file_ptr->name_ptr[0];
 285 #elif __BYTE_ORDER == __BIG_ENDIAN
 286   catalog->name_ptr = &catalog->file_ptr->name_ptr[catalog->plane_size
 287                                                   * catalog->plane_depth
 288                                                   * 3];
 289 #else
 290 # error Cannot handle __BYTE_ORDER byte order
 291 #endif
 292
 293   /* The rest of the file contains all the strings.  They are
 294      addressed relative to the position of the first string.  */
 295   catalog->strings =
 296     (const char *) &catalog->file_ptr->name_ptr[catalog->plane_size
 297                                                * catalog->plane_depth * 3 * 2];
 298
 299   /* Determine the largest string offset mentioned in the table.  */
 300   max_offset = 0;
 301   tab_size = 3 * catalog->plane_size * catalog->plane_depth;
 302   for (cnt = 2; cnt < tab_size; cnt += 3)
 303     if (catalog->name_ptr[cnt] > max_offset)
 304       max_offset = catalog->name_ptr[cnt];
 305
 306   /* Now we can check whether the file is large enough to contain the
 307      tables it says it contains.  */
 308   if (st.st_size <= (sizeof (struct catalog_obj) + 2 * tab_size + max_offset))
 309     /* The last string is not contained in the file.  */
 310     goto invalid_file;
 311
 312   lastp = catalog->strings + max_offset;
 313   max_offset = (st.st_size
 314                 - sizeof (struct catalog_obj) + 2 * tab_size + max_offset);
 315   while (*lastp != '\0')
 316     {
 317       if (--max_offset == 0)
 318         goto invalid_file;
 319       ++lastp;
 320     }
 321
 322   /* Release the lock again.  */
 323  unlock_return:
 324   if (fd != -1)
 325     __close (fd);
 326   __libc_lock_unlock (catalog->lock);
 327 }