catgets/open_catalog.c

   1 /* Copyright (C) 1996-2015 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, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <byteswap.h>
  20 #include <endian.h>
  21 #include <errno.h>
  22 #include <fcntl.h>
  23 #include <string.h>
  24 #include <stdlib.h>
  25 #include <unistd.h>
  26 #ifdef _POSIX_MAPPED_FILES
  27 # include <sys/mman.h>
  28 #endif
  29 #include <sys/stat.h>
  30
  31 #include "catgetsinfo.h"
  32 #include <not-cancel.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_not_cancel_2 (cat_name, O_RDONLY);
  53   else
  54     {
  55       const char *run_nlspath = nlspath;
  56 #define ENOUGH(n)                                                             \
  57   if (__glibc_unlikely (bufact + (n) >= bufmax))                              \
  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_not_cancel_2 (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       || (size_t) 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   catalog->file_ptr =
 216     (struct catalog_obj *) __mmap (NULL, st.st_size, PROT_READ,
 217                                    MAP_FILE|MAP_COPY, fd, 0);
 218   if (__builtin_expect (catalog->file_ptr != (struct catalog_obj *) MAP_FAILED,
 219                         1))
 220     /* Tell the world we managed to mmap the file.  */
 221     catalog->status = mmapped;
 222   else
 223 #endif /* _POSIX_MAPPED_FILES */
 224     {
 225       /* mmap failed perhaps because the system call is not
 226          implemented.  Try to load the file.  */
 227       size_t todo;
 228       catalog->file_ptr = malloc (st.st_size);
 229       if (catalog->file_ptr == NULL)
 230         goto close_unlock_return;
 231
 232       todo = st.st_size;
 233       /* Save read, handle partial reads.  */
 234       do
 235         {
 236           size_t now = read_not_cancel (fd, (((char *) catalog->file_ptr)
 237                                              + (st.st_size - todo)), todo);
 238           if (now == 0 || now == (size_t) -1)
 239             {
 240 #ifdef EINTR
 241               if (now == (size_t) -1 && errno == EINTR)
 242                 continue;
 243 #endif
 244               free ((void *) catalog->file_ptr);
 245               goto close_unlock_return;
 246             }
 247           todo -= now;
 248         }
 249       while (todo > 0);
 250       catalog->status = malloced;
 251     }
 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 (__glibc_likely (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       goto close_unlock_return;
 272     }
 273
 274 #define SWAP(x) (swapping ? SWAPU32 (x) : (x))
 275
 276   /* Get dimensions of the used hashing table.  */
 277   catalog->plane_size = SWAP (catalog->file_ptr->plane_size);
 278   catalog->plane_depth = SWAP (catalog->file_ptr->plane_depth);
 279
 280   /* The file contains two versions of the pointer tables.  Pick the
 281      right one for the local byte order.  */
 282 #if __BYTE_ORDER == __LITTLE_ENDIAN
 283   catalog->name_ptr = &catalog->file_ptr->name_ptr[0];
 284 #elif __BYTE_ORDER == __BIG_ENDIAN
 285   catalog->name_ptr = &catalog->file_ptr->name_ptr[catalog->plane_size
 286                                                   * catalog->plane_depth
 287                                                   * 3];
 288 #else
 289 # error Cannot handle __BYTE_ORDER byte order
 290 #endif
 291
 292   /* The rest of the file contains all the strings.  They are
 293      addressed relative to the position of the first string.  */
 294   catalog->strings =
 295     (const char *) &catalog->file_ptr->name_ptr[catalog->plane_size
 296                                                * catalog->plane_depth * 3 * 2];
 297
 298   /* Determine the largest string offset mentioned in the table.  */
 299   max_offset = 0;
 300   tab_size = 3 * catalog->plane_size * catalog->plane_depth;
 301   for (cnt = 2; cnt < tab_size; cnt += 3)
 302     if (catalog->name_ptr[cnt] > max_offset)
 303       max_offset = catalog->name_ptr[cnt];
 304
 305   /* Now we can check whether the file is large enough to contain the
 306      tables it says it contains.  */
 307   if ((size_t) st.st_size
 308       <= (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   /* We succeeded.  */
 323   result = 0;
 324
 325   /* Release the lock again.  */
 326  close_unlock_return:
 327   close_not_cancel_no_status (fd);
 328
 329   return result;
 330 }
 331 libc_hidden_def (__open_catalog)