catgets/open_catalog.c

   1 /* Copyright (C) 1996-2017 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   char *buf = NULL;
  51
  52   if (strchr (cat_name, '/') != NULL || nlspath == NULL)
  53     fd = open_not_cancel_2 (cat_name, O_RDONLY);
  54   else
  55     {
  56       const char *run_nlspath = nlspath;
  57 #define ENOUGH(n)                                                             \
  58   if (__glibc_unlikely (bufact + (n) >= bufmax))                              \
  59     {                                                                         \
  60       char *old_buf = buf;                                                    \
  61       bufmax += (bufmax < 256 + (n)) ? 256 + (n) : bufmax;                    \
  62       buf = realloc (buf, bufmax);                                            \
  63       if (__glibc_unlikely (buf == NULL))                                     \
  64         {                                                                     \
  65           free (old_buf);                                                     \
  66           return -1;                                                          \
  67         }                                                                     \
  68     }
  69
  70       /* The RUN_NLSPATH variable contains a colon separated list of
  71          descriptions where we expect to find catalogs.  We have to
  72          recognize certain % substitutions and stop when we found the
  73          first existing file.  */
  74       size_t bufact;
  75       size_t bufmax = 0;
  76       size_t len;
  77
  78       fd = -1;
  79       while (*run_nlspath != '\0')
  80         {
  81           bufact = 0;
  82
  83           if (*run_nlspath == ':')
  84             {
  85               /* Leading colon or adjacent colons - treat same as %N.  */
  86               len = strlen (cat_name);
  87               ENOUGH (len);
  88               memcpy (&buf[bufact], cat_name, len);
  89               bufact += len;
  90             }
  91           else
  92             while (*run_nlspath != ':' && *run_nlspath != '\0')
  93               if (*run_nlspath == '%')
  94                 {
  95                   const char *tmp;
  96
  97                   ++run_nlspath;        /* We have seen the `%'.  */
  98                   switch (*run_nlspath++)
  99                     {
 100                     case 'N':
 101                       /* Use the catalog name.  */
 102                       len = strlen (cat_name);
 103                       ENOUGH (len);
 104                       memcpy (&buf[bufact], cat_name, len);
 105                       bufact += len;
 106                       break;
 107                     case 'L':
 108                       /* Use the current locale category value.  */
 109                       len = strlen (env_var);
 110                       ENOUGH (len);
 111                       memcpy (&buf[bufact], env_var, len);
 112                       bufact += len;
 113                       break;
 114                     case 'l':
 115                       /* Use language element of locale category value.  */
 116                       tmp = env_var;
 117                       do
 118                         {
 119                           ENOUGH (1);
 120                           buf[bufact++] = *tmp++;
 121                         }
 122                       while (*tmp != '\0' && *tmp != '_' && *tmp != '.');
 123                       break;
 124                     case 't':
 125                       /* Use territory element of locale category value.  */
 126                       tmp = env_var;
 127                       do
 128                         ++tmp;
 129                       while (*tmp != '\0' && *tmp != '_' && *tmp != '.');
 130                       if (*tmp == '_')
 131                         {
 132                           ++tmp;
 133                           do
 134                             {
 135                               ENOUGH (1);
 136                               buf[bufact++] = *tmp++;
 137                             }
 138                           while (*tmp != '\0' && *tmp != '.');
 139                         }
 140                       break;
 141                     case 'c':
 142                       /* Use code set element of locale category value.  */
 143                       tmp = env_var;
 144                       do
 145                         ++tmp;
 146                       while (*tmp != '\0' && *tmp != '.');
 147                       if (*tmp == '.')
 148                         {
 149                           ++tmp;
 150                           do
 151                             {
 152                               ENOUGH (1);
 153                               buf[bufact++] = *tmp++;
 154                             }
 155                           while (*tmp != '\0');
 156                         }
 157                       break;
 158                     case '%':
 159                       ENOUGH (1);
 160                       buf[bufact++] = '%';
 161                       break;
 162                     default:
 163                       /* Unknown variable: ignore this path element.  */
 164                       bufact = 0;
 165                       while (*run_nlspath != '\0' && *run_nlspath != ':')
 166                         ++run_nlspath;
 167                       break;
 168                     }
 169                 }
 170               else
 171                 {
 172                   ENOUGH (1);
 173                   buf[bufact++] = *run_nlspath++;
 174                 }
 175
 176           ENOUGH (1);
 177           buf[bufact] = '\0';
 178
 179           if (bufact != 0)
 180             {
 181               fd = open_not_cancel_2 (buf, O_RDONLY);
 182               if (fd >= 0)
 183                 break;
 184             }
 185
 186           ++run_nlspath;
 187         }
 188     }
 189
 190   /* Avoid dealing with directories and block devices */
 191   if (__builtin_expect (fd, 0) < 0)
 192     {
 193       free (buf);
 194       return -1;
 195     }
 196
 197   if (__builtin_expect (__fxstat64 (_STAT_VER, fd, &st), 0) < 0)
 198     goto close_unlock_return;
 199
 200   if (__builtin_expect (!S_ISREG (st.st_mode), 0)
 201       || (size_t) st.st_size < sizeof (struct catalog_obj))
 202     {
 203       /* `errno' is not set correctly but the file is not usable.
 204          Use an reasonable error value.  */
 205       __set_errno (EINVAL);
 206       goto close_unlock_return;
 207     }
 208
 209   catalog->file_size = st.st_size;
 210 #ifdef _POSIX_MAPPED_FILES
 211 # ifndef MAP_COPY
 212     /* Linux seems to lack read-only copy-on-write.  */
 213 #  define MAP_COPY MAP_PRIVATE
 214 # endif
 215 # ifndef MAP_FILE
 216     /* Some systems do not have this flag; it is superfluous.  */
 217 #  define MAP_FILE 0
 218 # endif
 219   catalog->file_ptr =
 220     (struct catalog_obj *) __mmap (NULL, st.st_size, PROT_READ,
 221                                    MAP_FILE|MAP_COPY, 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_not_cancel (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 (__glibc_likely (catalog->file_ptr->magic == CATGETS_MAGIC))
 261     swapping = 0;
 262   else if (catalog->file_ptr->magic == SWAPU32 (CATGETS_MAGIC))
 263     swapping = 1;
 264   else
 265     {
 266     invalid_file:
 267       /* Invalid file.  Free the resources and mark catalog as not
 268          usable.  */
 269 #ifdef _POSIX_MAPPED_FILES
 270       if (catalog->status == mmapped)
 271         __munmap ((void *) catalog->file_ptr, catalog->file_size);
 272       else
 273 #endif  /* _POSIX_MAPPED_FILES */
 274         free (catalog->file_ptr);
 275       goto close_unlock_return;
 276     }
 277
 278 #define SWAP(x) (swapping ? SWAPU32 (x) : (x))
 279
 280   /* Get dimensions of the used hashing table.  */
 281   catalog->plane_size = SWAP (catalog->file_ptr->plane_size);
 282   catalog->plane_depth = SWAP (catalog->file_ptr->plane_depth);
 283
 284   /* The file contains two versions of the pointer tables.  Pick the
 285      right one for the local byte order.  */
 286 #if __BYTE_ORDER == __LITTLE_ENDIAN
 287   catalog->name_ptr = &catalog->file_ptr->name_ptr[0];
 288 #elif __BYTE_ORDER == __BIG_ENDIAN
 289   catalog->name_ptr = &catalog->file_ptr->name_ptr[catalog->plane_size
 290                                                   * catalog->plane_depth
 291                                                   * 3];
 292 #else
 293 # error Cannot handle __BYTE_ORDER byte order
 294 #endif
 295
 296   /* The rest of the file contains all the strings.  They are
 297      addressed relative to the position of the first string.  */
 298   catalog->strings =
 299     (const char *) &catalog->file_ptr->name_ptr[catalog->plane_size
 300                                                * catalog->plane_depth * 3 * 2];
 301
 302   /* Determine the largest string offset mentioned in the table.  */
 303   max_offset = 0;
 304   tab_size = 3 * catalog->plane_size * catalog->plane_depth;
 305   for (cnt = 2; cnt < tab_size; cnt += 3)
 306     if (catalog->name_ptr[cnt] > max_offset)
 307       max_offset = catalog->name_ptr[cnt];
 308
 309   /* Now we can check whether the file is large enough to contain the
 310      tables it says it contains.  */
 311   if ((size_t) st.st_size
 312       <= (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_not_cancel_no_status (fd);
 332   free (buf);
 333
 334   return result;
 335 }
 336 libc_hidden_def (__open_catalog)