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 #ifndef MODE_USTAR
  27 /* cpio support */
  28 #define MAGIC_BCPIO     070707
  29 struct head
  30 {
  31   grub_uint16_t magic;
  32   grub_uint16_t dev;
  33   grub_uint16_t ino;
  34   grub_uint16_t mode;
  35   grub_uint16_t uid;
  36   grub_uint16_t gid;
  37   grub_uint16_t nlink;
  38   grub_uint16_t rdev;
  39   grub_uint16_t mtime_1;
  40   grub_uint16_t mtime_2;
  41   grub_uint16_t namesize;
  42   grub_uint16_t filesize_1;
  43   grub_uint16_t filesize_2;
  44 } __attribute__ ((packed));
  45 #else
  46 /* tar support */
  47 #define MAGIC_USTAR     "ustar"
  48 struct head
  49 {
  50   char name[100];
  51   char mode[8];
  52   char uid[8];
  53   char gid[8];
  54   char size[12];
  55   char mtime[12];
  56   char chksum[8];
  57   char typeflag;
  58   char linkname[100];
  59   char magic[6];
  60   char version[2];
  61   char uname[32];
  62   char gname[32];
  63   char devmajor[8];
  64   char devminor[8];
  65   char prefix[155];
  66 } __attribute__ ((packed));
  67 #endif
  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 static grub_dl_t my_mod;
  78
  79 static grub_err_t
  80 grub_cpio_find_file (struct grub_cpio_data *data, char **name,
  81                      grub_uint32_t * ofs)
  82 {
  83 #ifndef MODE_USTAR
  84       struct head hd;
  85
  86       if (grub_disk_read
  87           (data->disk, 0, data->hofs, sizeof (hd), &hd))
  88         return grub_errno;
  89
  90       if (hd.magic != MAGIC_BCPIO)
  91         return grub_error (GRUB_ERR_BAD_FS, "Invalid cpio archive");
  92
  93       data->size = (((grub_uint32_t) hd.filesize_1) << 16) + hd.filesize_2;
  94
  95       if (hd.namesize & 1)
  96         hd.namesize++;
  97
  98       if ((*name = grub_malloc (hd.namesize)) == NULL)
  99         return grub_errno;
 100
 101       if (grub_disk_read (data->disk, 0, data->hofs + sizeof (hd),
 102                           hd.namesize, *name))
 103         {
 104           grub_free (*name);
 105           return grub_errno;
 106         }
 107
 108       if (data->size == 0 && hd.mode == 0 && hd.namesize == 11 + 1
 109           && ! grub_memcmp(*name, "TRAILER!!!", 11))
 110         {
 111           *ofs = 0;
 112           return GRUB_ERR_NONE;
 113         }
 114
 115       data->dofs = data->hofs + sizeof (hd) + hd.namesize;
 116       *ofs = data->dofs + data->size;
 117       if (data->size & 1)
 118         (*ofs)++;
 119 #else
 120       struct head hd;
 121
 122       if (grub_disk_read
 123           (data->disk, 0, data->hofs, sizeof (hd), &hd))
 124         return grub_errno;
 125
 126       if (!hd.name[0])
 127         {
 128           *ofs = 0;
 129           return GRUB_ERR_NONE;
 130         }
 131
 132       if (grub_memcmp (hd.magic, MAGIC_USTAR, sizeof (MAGIC_USTAR) - 1))
 133         return grub_error (GRUB_ERR_BAD_FS, "Invalid tar archive");
 134
 135       if ((*name = grub_strdup (hd.name)) == NULL)
 136         return grub_errno;
 137
 138       data->size = grub_strtoul (hd.size, NULL, 8);
 139       data->dofs = data->hofs + GRUB_DISK_SECTOR_SIZE;
 140       *ofs = data->dofs + ((data->size + GRUB_DISK_SECTOR_SIZE - 1) &
 141                            ~(GRUB_DISK_SECTOR_SIZE - 1));
 142 #endif
 143   return GRUB_ERR_NONE;
 144 }
 145
 146 static struct grub_cpio_data *
 147 grub_cpio_mount (grub_disk_t disk)
 148 {
 149   struct head hd;
 150   struct grub_cpio_data *data;
 151
 152   if (grub_disk_read (disk, 0, 0, sizeof (hd), &hd))
 153     goto fail;
 154
 155 #ifndef MODE_USTAR
 156   if (hd.magic != MAGIC_BCPIO)
 157 #else
 158   if (grub_memcmp (hd.magic, MAGIC_USTAR,
 159                    sizeof (MAGIC_USTAR) - 1))
 160 #endif
 161     goto fail;
 162
 163   data = (struct grub_cpio_data *) grub_malloc (sizeof (*data));
 164   if (!data)
 165     goto fail;
 166
 167   data->disk = disk;
 168
 169   return data;
 170
 171 fail:
 172   grub_error (GRUB_ERR_BAD_FS, "not a "
 173 #ifdef MODE_USTAR
 174               "tar"
 175 #else
 176               "cpio"
 177 #endif
 178               " filesystem");
 179   return 0;
 180 }
 181
 182 static grub_err_t
 183 grub_cpio_dir (grub_device_t device, const char *path,
 184                int (*hook) (const char *filename,
 185                             const struct grub_dirhook_info *info))
 186 {
 187   struct grub_cpio_data *data;
 188   grub_uint32_t ofs;
 189   char *prev, *name;
 190   const char *np;
 191   int len;
 192
 193   grub_dl_ref (my_mod);
 194
 195   prev = 0;
 196
 197   data = grub_cpio_mount (device->disk);
 198   if (!data)
 199     goto fail;
 200
 201   np = path + 1;
 202   len = grub_strlen (path) - 1;
 203
 204   data->hofs = 0;
 205   while (1)
 206     {
 207       if (grub_cpio_find_file (data, &name, &ofs))
 208         goto fail;
 209
 210       if (!ofs)
 211         break;
 212
 213       if (grub_memcmp (np, name, len) == 0)
 214         {
 215           char *p, *n;
 216
 217           n = name + len;
 218           if (*n == '/')
 219             n++;
 220
 221           p = grub_strchr (name + len, '/');
 222           if (p)
 223             *p = 0;
 224
 225           if ((!prev) || (grub_strcmp (prev, name) != 0))
 226             {
 227               struct grub_dirhook_info info;
 228               grub_memset (&info, 0, sizeof (info));
 229               info.dir = (p != NULL);
 230
 231               hook (name + len, &info);
 232               if (prev)
 233                 grub_free (prev);
 234               prev = name;
 235             }
 236           else
 237             grub_free (name);
 238         }
 239       data->hofs = ofs;
 240     }
 241
 242 fail:
 243
 244   if (prev)
 245     grub_free (prev);
 246
 247   if (data)
 248     grub_free (data);
 249
 250   grub_dl_unref (my_mod);
 251
 252   return grub_errno;
 253 }
 254
 255 static grub_err_t
 256 grub_cpio_open (grub_file_t file, const char *name)
 257 {
 258   struct grub_cpio_data *data;
 259   grub_uint32_t ofs;
 260   char *fn;
 261   int i, j;
 262
 263   grub_dl_ref (my_mod);
 264
 265   data = grub_cpio_mount (file->device->disk);
 266   if (!data)
 267     goto fail;
 268
 269   data->hofs = 0;
 270   while (1)
 271     {
 272       if (grub_cpio_find_file (data, &fn, &ofs))
 273         goto fail;
 274
 275       if (!ofs)
 276         {
 277           grub_error (GRUB_ERR_FILE_NOT_FOUND, "file not found");
 278           break;
 279         }
 280
 281       /* Compare NAME and FN by hand in order to cope with duplicate
 282          slashes.  */
 283       i = 1;
 284       j = 0;
 285       while (1)
 286         {
 287           if (name[i] != fn[j])
 288             goto no_match;
 289
 290           if (name[i] == '\0')
 291             break;
 292
 293           if (name[i] == '/' && name[i+1] == '/')
 294             i++;
 295
 296           i++;
 297           j++;
 298         }
 299
 300       file->data = data;
 301       file->size = data->size;
 302       grub_free (fn);
 303
 304       return GRUB_ERR_NONE;
 305
 306     no_match:
 307
 308       grub_free (fn);
 309       data->hofs = ofs;
 310     }
 311
 312 fail:
 313
 314   if (data)
 315     grub_free (data);
 316
 317   grub_dl_unref (my_mod);
 318
 319   return grub_errno;
 320 }
 321
 322 static grub_ssize_t
 323 grub_cpio_read (grub_file_t file, char *buf, grub_size_t len)
 324 {
 325   struct grub_cpio_data *data;
 326
 327   data = file->data;
 328   return (grub_disk_read (data->disk, 0, data->dofs + file->offset,
 329                           len, buf)) ? -1 : (grub_ssize_t) len;
 330 }
 331
 332 static grub_err_t
 333 grub_cpio_close (grub_file_t file)
 334 {
 335   grub_free (file->data);
 336
 337   grub_dl_unref (my_mod);
 338
 339   return grub_errno;
 340 }
 341
 342 static struct grub_fs grub_cpio_fs = {
 343 #ifdef MODE_USTAR
 344   .name = "tarfs",
 345 #else
 346   .name = "cpiofs",
 347 #endif
 348   .dir = grub_cpio_dir,
 349   .open = grub_cpio_open,
 350   .read = grub_cpio_read,
 351   .close = grub_cpio_close,
 352 };
 353
 354 #ifdef MODE_USTAR
 355 GRUB_MOD_INIT (tar)
 356 #else
 357 GRUB_MOD_INIT (cpio)
 358 #endif
 359 {
 360   grub_fs_register (&grub_cpio_fs);
 361   my_mod = mod;
 362 }
 363
 364 #ifdef MODE_USTAR
 365 GRUB_MOD_FINI (tar)
 366 #else
 367 GRUB_MOD_FINI (cpio)
 368 #endif
 369 {
 370   grub_fs_unregister (&grub_cpio_fs);
 371 }