catgets/open_catalog.c

   1 /* Copyright (C) 1996-2000, 2001, 2002 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper, <drepper@gnu.org>.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the 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    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    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 int
  39 __open_catalog (const char *cat_name, const char *nlspath, const char *env_var,
  40                 __nl_catd catalog)
  41 {
  42   int fd = -1;
  43   struct stat64 st;
  44   int swapping;
  45   size_t cnt;
  46   size_t max_offset;
  47   size_t tab_size;
  48   const char *lastp;
  49   int result = -1;
  50
  51   if (strchr (cat_name, '/') != NULL || nlspath == NULL)
  52     fd = __open (cat_name, O_RDONLY);
  53   else
  54     {
  55       const char *run_nlspath = nlspath;
  56 #define ENOUGH(n)                                                             \
  57   if (__builtin_expect (bufact + (n) >= bufmax, 0))                           \
  58     {                                                                         \
  59       char *old_buf = buf;                                                    \
  60       bufmax += 256 + (n);                                                    \
  61       buf = (char *) alloca (bufmax);                                         \
  62       memcpy (buf, old_buf, bufact);                                          \
  63     }
  64
  65       /* The RUN_NLSPATH variable contains a colon separated list of
  66          descriptions where we expect to find catalogs.  We have to
  67          recognize certain % substitutions and stop when we found the
  68          first existing file.  */
  69       char *buf;
  70       size_t bufact;
  71       size_t bufmax;
  72       size_t len;
  73
  74       buf = NULL;
  75       bufmax = 0;
  76
  77       fd = -1;
  78       while (*run_nlspath != '\0')
  79         {
  80           bufact = 0;
  81
  82           if (*run_nlspath == ':')
  83             {
  84               /* Leading colon or adjacent colons - treat same as %N.  */
  85               len = strlen (cat_name);
  86               ENOUGH (len);
  87               memcpy (&buf[bufact], cat_name, len);
  88               bufact += len;
  89             }
  90           else
  91             while (*run_nlspath != ':' && *run_nlspath != '\0')
  92               if (*run_nlspath == '%')
  93                 {
  94                   const char *tmp;
  95
  96                   ++run_nlspath;        /* We have seen the `%'.  */
  97                   switch (*run_nlspath++)
  98                     {
  99                     case 'N':
 100                       /* Use the catalog name.  */
 101                       len = strlen (cat_name);
 102                       ENOUGH (len);
 103                       memcpy (&buf[bufact], cat_name, len);
 104                       bufact += len;
 105                       break;
 106                     case 'L':
 107                       /* Use the current locale category value.  */
 108                       len = strlen (env_var);
 109                       ENOUGH (len);
 110                       memcpy (&buf[bufact], env_var, len);
 111                       bufact += len;
 112                       break;
 113                     case 'l':
 114                       /* Use language element of locale category value.  */
 115                       tmp = env_var;
 116                       do
 117                         {
 118                           ENOUGH (1);
 119                           buf[bufact++] = *tmp++;
 120                         }
 121                       while (*tmp != '\0' && *tmp != '_' && *tmp != '.');
 122                       break;
 123                     case 't':
 124                       /* Use territory element of locale category value.  */
 125                       tmp = env_var;
 126                       do
 127                         ++tmp;
 128                       while (*tmp != '\0' && *tmp != '_' && *tmp != '.');
 129                       if (*tmp == '_')
 130                         {
 131                           ++tmp;
 132                           do
 133                             {
 134                               ENOUGH (1);
 135                               buf[bufact++] = *tmp++;
 136                             }
 137                           while (*tmp != '\0' && *tmp != '.');
 138                         }
 139                       break;
 140                     case 'c':
 141                       /* Use code set element of locale category value.  */
 142                       tmp = env_var;
 143                       do
 144                         ++tmp;
 145                       while (*tmp != '\0' && *tmp != '.');
 146                       if (*tmp == '.')
 147                         {
 148                           ++tmp;
 149                           do
 150                             {
 151                               ENOUGH (1);
 152                               buf[bufact++] = *tmp++;
 153                             }
 154                           while (*tmp != '\0');
 155                         }
 156                       break;
 157                     case '%':
 158                       ENOUGH (1);
 159                       buf[bufact++] = '%';
 160                       break;
 161                     default:
 162                       /* Unknown variable: ignore this path element.  */
 163                       bufact = 0;
 164                       while (*run_nlspath != '\0' && *run_nlspath != ':')
 165                         ++run_nlspath;
 166                       break;
 167                     }
 168                 }
 169               else
 170                 {
 171                   ENOUGH (1);
 172                   buf[bufact++] = *run_nlspath++;
 173                 }
 174
 175           ENOUGH (1);
 176           buf[bufact] = '\0';
 177
 178           if (bufact != 0)
 179             {
 180               fd = __open (buf, O_RDONLY);
 181               if (fd >= 0)
 182                 break;
 183             }
 184
 185           ++run_nlspath;
 186         }
 187     }
 188
 189   /* Avoid dealing with directories and block devices */
 190   if (__builtin_expect (fd, 0) < 0)
 191     return -1;
 192
 193   if (__builtin_expect (__fxstat64 (_STAT_VER, fd, &st), 0) < 0)
 194     goto close_unlock_return;
 195
 196   if (__builtin_expect (!S_ISREG (st.st_mode), 0)
 197       || st.st_size < sizeof (struct catalog_obj))
 198     {
 199       /* `errno' is not set correctly but the file is not usable.
 200          Use an reasonable error value.  */
 201       __set_errno (EINVAL);
 202       goto close_unlock_return;
 203     }
 204
 205   catalog->file_size = st.st_size;
 206 #ifdef _POSIX_MAPPED_FILES
 207 # ifndef MAP_COPY
 208     /* Linux seems to lack read-only copy-on-write.  */
 209 #  define MAP_COPY MAP_PRIVATE
 210 # endif
 211 # ifndef MAP_FILE
 212     /* Some systems do not have this flag; it is superfluous.  */
 213 #  define MAP_FILE 0
 214 # endif
 215 # ifndef MAP_INHERIT
 216     /* Some systems might lack this; they lose.  */
 217 #  define MAP_INHERIT 0
 218 # endif
 219   catalog->file_ptr =
 220     (struct catalog_obj *) __mmap (NULL, st.st_size, PROT_READ,
 221                                    MAP_FILE|MAP_COPY|MAP_INHERIT, fd, 0);
 222   if (__builtin_expect (catalog->file_ptr != (struct catalog_obj *) MAP_FAILED,
 223                         1))
 224     /* Tell the world we managed to mmap the file.  */
 225     catalog->status = mmapped;
 226   else
 227 #endif /* _POSIX_MAPPED_FILES */
 228     {
 229       /* mmap failed perhaps because the system call is not
 230          implemented.  Try to load the file.  */
 231       size_t todo;
 232       catalog->file_ptr = malloc (st.st_size);
 233       if (catalog->file_ptr == NULL)
 234         goto close_unlock_return;
 235
 236       todo = st.st_size;
 237       /* Save read, handle partial reads.  */
 238       do
 239         {
 240           size_t now = __read (fd, (((char *) catalog->file_ptr)
 241                                     + (st.st_size - todo)), todo);
 242           if (now == 0 || now == (size_t) -1)
 243             {
 244 #ifdef EINTR
 245               if (now == (size_t) -1 && errno == EINTR)
 246                 continue;
 247 #endif
 248               free ((void *) catalog->file_ptr);
 249               goto close_unlock_return;
 250             }
 251           todo -= now;
 252         }
 253       while (todo > 0);
 254       catalog->status = malloced;
 255     }
 256
 257   /* Determine whether the file is a catalog file and if yes whether
 258      it is written using the correct byte order.  Else we have to swap
 259      the values.  */
 260   if (__builtin_expect (catalog->file_ptr->magic, CATGETS_MAGIC)
 261       == CATGETS_MAGIC)
 262     swapping = 0;
 263   else if (catalog->file_ptr->magic == SWAPU32 (CATGETS_MAGIC))
 264     swapping = 1;
 265   else
 266     {
 267     invalid_file:
 268       /* Invalid file.  Free the resources and mark catalog as not
 269          usable.  */
 270 #ifdef _POSIX_MAPPED_FILES
 271       if (catalog->status == mmapped)
 272         __munmap ((void *) catalog->file_ptr, catalog->file_size);
 273       else
 274 #endif  /* _POSIX_MAPPED_FILES */
 275         free (catalog->file_ptr);
 276       goto close_unlock_return;
 277     }
 278
 279 #define SWAP(x) (swapping ? SWAPU32 (x) : (x))
 280
 281   /* Get dimensions of the used hashing table.  */
 282   catalog->plane_size = SWAP (catalog->file_ptr->plane_size);
 283   catalog->plane_depth = SWAP (catalog->file_ptr->plane_depth);
 284
 285   /* The file contains two versions of the pointer tables.  Pick the
 286      right one for the local byte order.  */
 287 #if __BYTE_ORDER == __LITTLE_ENDIAN
 288   catalog->name_ptr = &catalog->file_ptr->name_ptr[0];
 289 #elif __BYTE_ORDER == __BIG_ENDIAN
 290   catalog->name_ptr = &catalog->file_ptr->name_ptr[catalog->plane_size
 291                                                   * catalog->plane_depth
 292                                                   * 3];
 293 #else
 294 # error Cannot handle __BYTE_ORDER byte order
 295 #endif
 296
 297   /* The rest of the file contains all the strings.  They are
 298      addressed relative to the position of the first string.  */
 299   catalog->strings =
 300     (const char *) &catalog->file_ptr->name_ptr[catalog->plane_size
 301                                                * catalog->plane_depth * 3 * 2];
 302
 303   /* Determine the largest string offset mentioned in the table.  */
 304   max_offset = 0;
 305   tab_size = 3 * catalog->plane_size * catalog->plane_depth;
 306   for (cnt = 2; cnt < tab_size; cnt += 3)
 307     if (catalog->name_ptr[cnt] > max_offset)
 308       max_offset = catalog->name_ptr[cnt];
 309
 310   /* Now we can check whether the file is large enough to contain the
 311      tables it says it contains.  */
 312   if (st.st_size <= (sizeof (struct catalog_obj) + 2 * tab_size + max_offset))
 313     /* The last string is not contained in the file.  */
 314     goto invalid_file;
 315
 316   lastp = catalog->strings + max_offset;
 317   max_offset = (st.st_size
 318                 - sizeof (struct catalog_obj) + 2 * tab_size + max_offset);
 319   while (*lastp != '\0')
 320     {
 321       if (--max_offset == 0)
 322         goto invalid_file;
 323       ++lastp;
 324     }
 325
 326   /* We succeeded.  */
 327   result = 0;
 328
 329   /* Release the lock again.  */
 330  close_unlock_return:
 331   __close (fd);
 332
 333   return result;
 334 }