arch/common/boot/grub2/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 #define MODE_BCPIO      1
  70 #define MODE_USTAR      2
  71
  72 struct grub_cpio_data
  73 {
  74   grub_disk_t disk;
  75   grub_uint32_t hofs;
  76   grub_uint32_t dofs;
  77   grub_uint32_t size;
  78   int mode;
  79 };
  80
  81 #ifndef GRUB_UTIL
  82 static grub_dl_t my_mod;
  83 #endif
  84
  85 static grub_err_t
  86 grub_cpio_find_file (struct grub_cpio_data *data, char **name,
  87                      grub_uint32_t * ofs)
  88 {
  89   if (data->mode == MODE_BCPIO)
  90     {
  91       struct HEAD_BCPIO hd;
  92
  93       if (grub_disk_read
  94           (data->disk, 0, data->hofs, sizeof (hd), (char *) &hd))
  95         return grub_errno;
  96
  97       if (hd.magic != MAGIC_BCPIO)
  98         return grub_error (GRUB_ERR_BAD_FS, "Invalid cpio archive");
  99
 100       data->size = (((grub_uint32_t) hd.filesize_1) << 16) + hd.filesize_2;
 101
 102       if (hd.namesize & 1)
 103         hd.namesize++;
 104
 105       if ((*name = grub_malloc (hd.namesize)) == NULL)
 106         return grub_errno;
 107
 108       if (grub_disk_read (data->disk, 0, data->hofs + sizeof (hd),
 109                           hd.namesize, *name))
 110         {
 111           grub_free (*name);
 112           return grub_errno;
 113         }
 114
 115       if (data->size == 0 && hd.mode == 0 && hd.namesize == 11 + 1
 116           && ! grub_memcmp(*name, "TRAILER!!!", 11))
 117         {
 118           *ofs = 0;
 119           return GRUB_ERR_NONE;
 120         }
 121
 122       data->dofs = data->hofs + sizeof (hd) + hd.namesize;
 123       *ofs = data->dofs + data->size;
 124       if (data->size & 1)
 125         (*ofs)++;
 126     }
 127   else
 128     {
 129       struct HEAD_USTAR hd;
 130
 131       if (grub_disk_read
 132           (data->disk, 0, data->hofs, sizeof (hd), (char *) &hd))
 133         return grub_errno;
 134
 135       if (!hd.name[0])
 136         {
 137           *ofs = 0;
 138           return GRUB_ERR_NONE;
 139         }
 140
 141       if (grub_memcmp (hd.magic, MAGIC_USTAR, sizeof (MAGIC_USTAR) - 1))
 142         return grub_error (GRUB_ERR_BAD_FS, "Invalid tar archive");
 143
 144       if ((*name = grub_strdup (hd.name)) == NULL)
 145         return grub_errno;
 146
 147       data->size = grub_strtoul (hd.size, NULL, 8);
 148       data->dofs = data->hofs + GRUB_DISK_SECTOR_SIZE;
 149       *ofs = data->dofs + ((data->size + GRUB_DISK_SECTOR_SIZE - 1) &
 150                            ~(GRUB_DISK_SECTOR_SIZE - 1));
 151     }
 152   return GRUB_ERR_NONE;
 153 }
 154
 155 static struct grub_cpio_data *
 156 grub_cpio_mount (grub_disk_t disk)
 157 {
 158   char hd[HEAD_LENG];
 159   struct grub_cpio_data *data;
 160   int mode;
 161
 162   if (grub_disk_read (disk, 0, 0, sizeof (hd), hd))
 163     goto fail;
 164
 165   if (((struct HEAD_BCPIO *) hd)->magic == MAGIC_BCPIO)
 166     mode = MODE_BCPIO;
 167   else if (!grub_memcmp (((struct HEAD_USTAR *) hd)->magic, MAGIC_USTAR,
 168                          sizeof (MAGIC_USTAR) - 1))
 169     mode = MODE_USTAR;
 170   else
 171     goto fail;
 172
 173   data = (struct grub_cpio_data *) grub_malloc (sizeof (*data));
 174   if (!data)
 175     goto fail;
 176
 177   data->disk = disk;
 178   data->mode = mode;
 179
 180   return data;
 181
 182 fail:
 183   grub_error (GRUB_ERR_BAD_FS, "not a cpio filesystem");
 184   return 0;
 185 }
 186
 187 static grub_err_t
 188 grub_cpio_dir (grub_device_t device, const char *path,
 189                int (*hook) (const char *filename, int dir))
 190 {
 191   struct grub_cpio_data *data;
 192   grub_uint32_t ofs;
 193   char *prev, *name;
 194   const char *np;
 195   int len;
 196
 197 #ifndef GRUB_UTIL
 198   grub_dl_ref (my_mod);
 199 #endif
 200
 201   prev = 0;
 202
 203   data = grub_cpio_mount (device->disk);
 204   if (!data)
 205     goto fail;
 206
 207   np = path + 1;
 208   len = grub_strlen (path) - 1;
 209
 210   data->hofs = 0;
 211   while (1)
 212     {
 213       if (grub_cpio_find_file (data, &name, &ofs))
 214         goto fail;
 215
 216       if (!ofs)
 217         break;
 218
 219       if (grub_memcmp (np, name, len) == 0)
 220         {
 221           char *p, *n;
 222
 223           n = name + len;
 224           if (*n == '/')
 225             n++;
 226
 227           p = grub_strchr (name + len, '/');
 228           if (p)
 229             *p = 0;
 230
 231           if ((!prev) || (grub_strcmp (prev, name) != 0))
 232             {
 233               hook (name + len, p != NULL);
 234               if (prev)
 235                 grub_free (prev);
 236               prev = name;
 237             }
 238           else
 239             grub_free (name);
 240         }
 241       data->hofs = ofs;
 242     }
 243
 244 fail:
 245
 246   if (prev)
 247     grub_free (prev);
 248
 249   if (data)
 250     grub_free (data);
 251
 252 #ifndef GRUB_UTIL
 253   grub_dl_unref (my_mod);
 254 #endif
 255
 256   return grub_errno;
 257 }
 258
 259 static grub_err_t
 260 grub_cpio_open (grub_file_t file, const char *name)
 261 {
 262   struct grub_cpio_data *data;
 263   grub_uint32_t ofs;
 264   char *fn;
 265
 266 #ifndef GRUB_UTIL
 267   grub_dl_ref (my_mod);
 268 #endif
 269
 270   data = grub_cpio_mount (file->device->disk);
 271   if (!data)
 272     goto fail;
 273
 274   data->hofs = 0;
 275   while (1)
 276     {
 277       if (grub_cpio_find_file (data, &fn, &ofs))
 278         goto fail;
 279
 280       if (!ofs)
 281         {
 282           grub_error (GRUB_ERR_FILE_NOT_FOUND, "file not found");
 283           break;
 284         }
 285
 286       if (grub_strcmp (name + 1, fn) == 0)
 287         {
 288           file->data = data;
 289           file->size = data->size;
 290           grub_free (fn);
 291
 292           return GRUB_ERR_NONE;
 293         }
 294
 295       grub_free (fn);
 296       data->hofs = ofs;
 297     }
 298
 299 fail:
 300
 301   if (data)
 302     grub_free (data);
 303
 304 #ifndef GRUB_UTIL
 305   grub_dl_unref (my_mod);
 306 #endif
 307
 308   return grub_errno;
 309 }
 310
 311 static grub_ssize_t
 312 grub_cpio_read (grub_file_t file, char *buf, grub_size_t len)
 313 {
 314   struct grub_cpio_data *data;
 315
 316   data = file->data;
 317   return (grub_disk_read (data->disk, 0, data->dofs + file->offset,
 318                           len, buf)) ? -1 : (grub_ssize_t) len;
 319 }
 320
 321 static grub_err_t
 322 grub_cpio_close (grub_file_t file)
 323 {
 324   grub_free (file->data);
 325
 326 #ifndef GRUB_UTIL
 327   grub_dl_unref (my_mod);
 328 #endif
 329
 330   return grub_errno;
 331 }
 332
 333 static struct grub_fs grub_cpio_fs = {
 334   .name = "cpiofs",
 335   .dir = grub_cpio_dir,
 336   .open = grub_cpio_open,
 337   .read = grub_cpio_read,
 338   .close = grub_cpio_close,
 339   .label = 0,
 340   .next = 0
 341 };
 342
 343 GRUB_MOD_INIT (cpio)
 344 {
 345   grub_fs_register (&grub_cpio_fs);
 346 #ifndef GRUB_UTIL
 347   my_mod = mod;
 348 #endif
 349 }
 350
 351 GRUB_MOD_FINI (cpio)
 352 {
 353   grub_fs_unregister (&grub_cpio_fs);
 354 }