fs/cpio.c

   1 /* cpio.c - cpio and tar filesystem.  */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 2007,2008 Free Software Foundation, Inc.
   5  *
   6  *  This program is free software: you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation, either version 3 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <grub/file.h>
  21 #include <grub/mm.h>
  22 #include <grub/misc.h>
  23 #include <grub/disk.h>
  24 #include <grub/dl.h>
  25
  26 #define MAGIC_BCPIO     070707
  27
  28 struct HEAD_BCPIO
  29 {
  30   grub_uint16_t magic;
  31   grub_uint16_t dev;
  32   grub_uint16_t ino;
  33   grub_uint16_t mode;
  34   grub_uint16_t uid;
  35   grub_uint16_t gid;
  36   grub_uint16_t nlink;
  37   grub_uint16_t rdev;
  38   grub_uint16_t mtime_1;
  39   grub_uint16_t mtime_2;
  40   grub_uint16_t namesize;
  41   grub_uint16_t filesize_1;
  42   grub_uint16_t filesize_2;
  43 } __attribute__ ((packed));
  44
  45 #define MAGIC_USTAR     "ustar"
  46
  47 struct HEAD_USTAR
  48 {
  49   char name[100];
  50   char mode[8];
  51   char uid[8];
  52   char gid[8];
  53   char size[12];
  54   char mtime[12];
  55   char chksum[8];
  56   char typeflag;
  57   char linkname[100];
  58   char magic[6];
  59   char version[2];
  60   char uname[32];
  61   char gname[32];
  62   char devmajor[8];
  63   char devminor[8];
  64   char prefix[155];
  65 } __attribute__ ((packed));
  66
  67 #define HEAD_LENG       sizeof(struct HEAD_USTAR)
  68
  69 struct grub_cpio_data
  70 {
  71   grub_disk_t disk;
  72   grub_uint32_t hofs;
  73   grub_uint32_t dofs;
  74   grub_uint32_t size;
  75 };
  76
  77 #ifndef GRUB_UTIL
  78 static grub_dl_t my_mod;
  79 #endif
  80
  81 static grub_err_t
  82 grub_cpio_find_file (struct grub_cpio_data *data, char **name,
  83                      grub_uint32_t * ofs)
  84 {
  85 #ifndef MODE_USTAR
  86       struct HEAD_BCPIO hd;
  87
  88       if (grub_disk_read
  89           (data->disk, 0, data->hofs, sizeof (hd), (char *) &hd))
  90         return grub_errno;
  91
  92       if (hd.magic != MAGIC_BCPIO)
  93         return grub_error (GRUB_ERR_BAD_FS, "Invalid cpio archive");
  94
  95       data->size = (((grub_uint32_t) hd.filesize_1) << 16) + hd.filesize_2;
  96
  97       if (hd.namesize & 1)
  98         hd.namesize++;
  99
 100       if ((*name = grub_malloc (hd.namesize)) == NULL)
 101         return grub_errno;
 102
 103       if (grub_disk_read (data->disk, 0, data->hofs + sizeof (hd),
 104                           hd.namesize, *name))
 105         {
 106           grub_free (*name);
 107           return grub_errno;
 108         }
 109
 110       if (data->size == 0 && hd.mode == 0 && hd.namesize == 11 + 1
 111           && ! grub_memcmp(*name, "TRAILER!!!", 11))
 112         {
 113           *ofs = 0;
 114           return GRUB_ERR_NONE;
 115         }
 116
 117       data->dofs = data->hofs + sizeof (hd) + hd.namesize;
 118       *ofs = data->dofs + data->size;
 119       if (data->size & 1)
 120         (*ofs)++;
 121 #else
 122       struct HEAD_USTAR hd;
 123
 124       if (grub_disk_read
 125           (data->disk, 0, data->hofs, sizeof (hd), (char *) &hd))
 126         return grub_errno;
 127
 128       if (!hd.name[0])
 129         {
 130           *ofs = 0;
 131           return GRUB_ERR_NONE;
 132         }
 133
 134       if (grub_memcmp (hd.magic, MAGIC_USTAR, sizeof (MAGIC_USTAR) - 1))
 135         return grub_error (GRUB_ERR_BAD_FS, "Invalid tar archive");
 136
 137       if ((*name = grub_strdup (hd.name)) == NULL)
 138         return grub_errno;
 139
 140       data->size = grub_strtoul (hd.size, NULL, 8);
 141       data->dofs = data->hofs + GRUB_DISK_SECTOR_SIZE;
 142       *ofs = data->dofs + ((data->size + GRUB_DISK_SECTOR_SIZE - 1) &
 143                            ~(GRUB_DISK_SECTOR_SIZE - 1));
 144 #endif
 145   return GRUB_ERR_NONE;
 146 }
 147
 148 static struct grub_cpio_data *
 149 grub_cpio_mount (grub_disk_t disk)
 150 {
 151   char hd[HEAD_LENG];
 152   struct grub_cpio_data *data;
 153
 154   if (grub_disk_read (disk, 0, 0, sizeof (hd), hd))
 155     goto fail;
 156
 157 #ifndef MODE_USTAR
 158   if (((struct HEAD_BCPIO *) hd)->magic != MAGIC_BCPIO)
 159 #else
 160   if (grub_memcmp (((struct HEAD_USTAR *) hd)->magic, MAGIC_USTAR,
 161                          sizeof (MAGIC_USTAR) - 1))
 162 #endif
 163     goto fail;
 164
 165   data = (struct grub_cpio_data *) grub_malloc (sizeof (*data));
 166   if (!data)
 167     goto fail;
 168
 169   data->disk = disk;
 170
 171   return data;
 172
 173 fail:
 174   grub_error (GRUB_ERR_BAD_FS, "not a "
 175 #ifdef MODE_USTAR
 176               "tar"
 177 #else
 178               "cpio"
 179 #endif
 180               " filesystem");
 181   return 0;
 182 }
 183
 184 static grub_err_t
 185 grub_cpio_dir (grub_device_t device, const char *path,
 186                int (*hook) (const char *filename, int dir))
 187 {
 188   struct grub_cpio_data *data;
 189   grub_uint32_t ofs;
 190   char *prev, *name;
 191   const char *np;
 192   int len;
 193
 194 #ifndef GRUB_UTIL
 195   grub_dl_ref (my_mod);
 196 #endif
 197
 198   prev = 0;
 199
 200   data = grub_cpio_mount (device->disk);
 201   if (!data)
 202     goto fail;
 203
 204   np = path + 1;
 205   len = grub_strlen (path) - 1;
 206
 207   data->hofs = 0;
 208   while (1)
 209     {
 210       if (grub_cpio_find_file (data, &name, &ofs))
 211         goto fail;
 212
 213       if (!ofs)
 214         break;
 215
 216       if (grub_memcmp (np, name, len) == 0)
 217         {
 218           char *p, *n;
 219
 220           n = name + len;
 221           if (*n == '/')
 222             n++;
 223
 224           p = grub_strchr (name + len, '/');
 225           if (p)
 226             *p = 0;
 227
 228           if ((!prev) || (grub_strcmp (prev, name) != 0))
 229             {
 230               hook (name + len, p != NULL);
 231               if (prev)
 232                 grub_free (prev);
 233               prev = name;
 234             }
 235           else
 236             grub_free (name);
 237         }
 238       data->hofs = ofs;
 239     }
 240
 241 fail:
 242
 243   if (prev)
 244     grub_free (prev);
 245
 246   if (data)
 247     grub_free (data);
 248
 249 #ifndef GRUB_UTIL
 250   grub_dl_unref (my_mod);
 251 #endif
 252
 253   return grub_errno;
 254 }
 255
 256 static grub_err_t
 257 grub_cpio_open (grub_file_t file, const char *name)
 258 {
 259   struct grub_cpio_data *data;
 260   grub_uint32_t ofs;
 261   char *fn;
 262   int i, j;
 263
 264 #ifndef GRUB_UTIL
 265   grub_dl_ref (my_mod);
 266 #endif
 267
 268   data = grub_cpio_mount (file->device->disk);
 269   if (!data)
 270     goto fail;
 271
 272   data->hofs = 0;
 273   while (1)
 274     {
 275       if (grub_cpio_find_file (data, &fn, &ofs))
 276         goto fail;
 277
 278       if (!ofs)
 279         {
 280           grub_error (GRUB_ERR_FILE_NOT_FOUND, "file not found");
 281           break;
 282         }
 283
 284       /* Compare NAME and FN by hand in order to cope with duplicate
 285          slashes.  */
 286       i = 1;
 287       j = 0;
 288       while (1)
 289         {
 290           if (name[i] != fn[j])
 291             goto no_match;
 292
 293           if (name[i] == '\0')
 294             break;
 295
 296           if (name[i] == '/' && name[i+1] == '/')
 297             i++;
 298
 299           i++;
 300           j++;
 301         }
 302
 303       file->data = data;
 304       file->size = data->size;
 305       grub_free (fn);
 306
 307       return GRUB_ERR_NONE;
 308
 309     no_match:
 310
 311       grub_free (fn);
 312       data->hofs = ofs;
 313     }
 314
 315 fail:
 316
 317   if (data)
 318     grub_free (data);
 319
 320 #ifndef GRUB_UTIL
 321   grub_dl_unref (my_mod);
 322 #endif
 323
 324   return grub_errno;
 325 }
 326
 327 static grub_ssize_t
 328 grub_cpio_read (grub_file_t file, char *buf, grub_size_t len)
 329 {
 330   struct grub_cpio_data *data;
 331
 332   data = file->data;
 333   return (grub_disk_read (data->disk, 0, data->dofs + file->offset,
 334                           len, buf)) ? -1 : (grub_ssize_t) len;
 335 }
 336
 337 static grub_err_t
 338 grub_cpio_close (grub_file_t file)
 339 {
 340   grub_free (file->data);
 341
 342 #ifndef GRUB_UTIL
 343   grub_dl_unref (my_mod);
 344 #endif
 345
 346   return grub_errno;
 347 }
 348
 349 static struct grub_fs grub_cpio_fs = {
 350 #ifdef MODE_USTAR
 351   .name = "tarfs",
 352 #else
 353   .name = "cpiofs",
 354 #endif
 355   .dir = grub_cpio_dir,
 356   .open = grub_cpio_open,
 357   .read = grub_cpio_read,
 358   .close = grub_cpio_close,
 359 };
 360
 361 #ifdef MODE_USTAR
 362 GRUB_MOD_INIT (cpio)
 363 #else
 364 GRUB_MOD_INIT (tar)
 365 #endif
 366 {
 367   grub_fs_register (&grub_cpio_fs);
 368 #ifndef GRUB_UTIL
 369   my_mod = mod;
 370 #endif
 371 }
 372
 373 #ifdef MODE_USTAR
 374 GRUB_MOD_FINI (cpio)
 375 #else
 376 GRUB_MOD_FINI (tar)
 377 #endif
 378 {
 379   grub_fs_unregister (&grub_cpio_fs);
 380 }