GRUB2/MOD_SRC/grub-2.04/grub-core/kern/file.c

   1 /* file.c - file I/O functions */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 2002,2006,2007,2009  Free Software Foundation, Inc.
   5  *
   6  *  GRUB 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  *  GRUB 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 GRUB.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <grub/misc.h>
  21 #include <grub/err.h>
  22 #include <grub/file.h>
  23 #include <grub/net.h>
  24 #include <grub/mm.h>
  25 #include <grub/fs.h>
  26 #include <grub/device.h>
  27 #include <grub/i18n.h>
  28
  29 void (*EXPORT_VAR (grub_grubnet_fini)) (void);
  30
  31 grub_file_filter_t grub_file_filters[GRUB_FILE_FILTER_MAX];
  32
  33 /* Get the device part of the filename NAME. It is enclosed by parentheses.  */
  34 char *
  35 grub_file_get_device_name (const char *name)
  36 {
  37   if (name[0] == '(')
  38     {
  39       char *p = grub_strchr (name, ')');
  40       char *ret;
  41
  42       if (! p)
  43         {
  44           grub_error (GRUB_ERR_BAD_FILENAME, N_("missing `%c' symbol"), ')');
  45           return 0;
  46         }
  47
  48       ret = (char *) grub_malloc (p - name);
  49       if (! ret)
  50         return 0;
  51
  52       grub_memcpy (ret, name + 1, p - name - 1);
  53       ret[p - name - 1] = '\0';
  54       return ret;
  55     }
  56
  57   return 0;
  58 }
  59
  60 /* Support mem:xxx:size:xxx format in chainloader */
  61 grub_file_t grub_memfile_open(const char *name);
  62 #define GRUB_MEMFILE_MEM     "mem:"
  63 #define GRUB_MEMFILE_SIZE    "size:"
  64
  65 grub_file_t grub_memfile_open(const char *name)
  66 {
  67     char *size = NULL;
  68     grub_file_t file = 0;
  69
  70     file = (grub_file_t)grub_zalloc(sizeof(*file));
  71     if (NULL == file)
  72     {
  73         return 0;
  74     }
  75
  76     file->name = grub_strdup(name);
  77     file->data = (void *)grub_strtoul(name + grub_strlen(GRUB_MEMFILE_MEM), NULL, 0);
  78
  79     size = grub_strstr(name, GRUB_MEMFILE_SIZE);
  80     file->size = (grub_off_t)grub_strtoul(size + grub_strlen(GRUB_MEMFILE_SIZE), NULL, 0);
  81
  82     grub_errno = GRUB_ERR_NONE;
  83     return file;
  84 }
  85
  86 int ventoy_check_file_exist(const char * fmt, ...)
  87 {
  88     va_list ap;
  89     grub_file_t file;
  90     char fullpath[256] = {0};
  91
  92     va_start (ap, fmt);
  93     grub_vsnprintf(fullpath, 255, fmt, ap);
  94     va_end (ap);
  95
  96     file = grub_file_open(fullpath, GRUB_FILE_TYPE_NONE);
  97     if (!file)
  98     {
  99         grub_errno = 0;
 100         return 0;
 101     }
 102     else
 103     {
 104         grub_file_close(file);
 105         return 1;
 106     }
 107 }
 108
 109 typedef struct grub_vlnk
 110 {
 111     int srclen;
 112     char src[512];
 113     char dst[512];
 114     struct grub_vlnk *next;
 115 }grub_vlnk;
 116
 117 static grub_vlnk g_vtoy_vlnk;
 118 static grub_vlnk *g_vlnk_list;
 119
 120 int grub_file_is_vlnk_suffix(const char *name, int len)
 121 {
 122     grub_uint32_t suffix;
 123
 124     if (len > 9)
 125     {
 126         suffix = *(grub_uint32_t *)(name + len - 4);
 127         if (grub_strncmp(name + len - 9, ".vlnk.", 6) == 0)
 128         {
 129             /* .iso .wim .img .vhd .efi .dat */
 130             if (suffix == 0x6F73692E || suffix == 0x6D69772E ||
 131                 suffix == 0x676D692E || suffix == 0x6468762E ||
 132                 suffix == 0x6966652E || suffix == 0x7461642E)
 133             {
 134                 return 1;
 135             }
 136         }
 137         else if (len > 10 && grub_strncmp(name + len - 10, ".vlnk.", 6) == 0)
 138         {
 139             /* vhdx vtoy */
 140             if (suffix == 0x78646876 || suffix == 0x796F7476)
 141             {
 142                 return 1;
 143             }
 144         }
 145     }
 146
 147     return 0;
 148 }
 149
 150 int grub_file_vtoy_vlnk(const char *src, const char *dst)
 151 {
 152     if (src)
 153     {
 154         g_vtoy_vlnk.srclen = (int)grub_strlen(src);
 155         grub_strncpy(g_vtoy_vlnk.src, src, sizeof(g_vtoy_vlnk.src) - 1);
 156         grub_strncpy(g_vtoy_vlnk.dst, dst, sizeof(g_vtoy_vlnk.dst) - 1);
 157     }
 158     else
 159     {
 160         g_vtoy_vlnk.srclen = 0;
 161         g_vtoy_vlnk.src[0] = 0;
 162         g_vtoy_vlnk.dst[0] = 0;
 163     }
 164     return 0;
 165 }
 166
 167 int grub_file_add_vlnk(const char *src, const char *dst)
 168 {
 169     grub_vlnk *node = NULL;
 170
 171     if (src && dst)
 172     {
 173         node = grub_zalloc(sizeof(grub_vlnk));
 174         if (node)
 175         {
 176             node->srclen = (int)grub_strlen(src);
 177             grub_strncpy(node->src, src, sizeof(node->src) - 1);
 178             grub_strncpy(node->dst, dst, sizeof(node->dst) - 1);
 179
 180             node->next = g_vlnk_list;
 181             g_vlnk_list = node;
 182             return 0;
 183         }
 184     }
 185
 186     return 1;
 187 }
 188
 189 const char *grub_file_get_vlnk(const char *name, int *vlnk)
 190 {
 191     int len;
 192     grub_vlnk *node = g_vlnk_list;
 193
 194     len = grub_strlen(name);
 195
 196     if (!grub_file_is_vlnk_suffix(name, len))
 197     {
 198         return name;
 199     }
 200
 201     if (len == g_vtoy_vlnk.srclen && grub_strcmp(name, g_vtoy_vlnk.src) == 0)
 202     {
 203         if (vlnk)
 204             *vlnk = 1;
 205         return g_vtoy_vlnk.dst;
 206     }
 207
 208     while (node)
 209     {
 210         if (node->srclen == len && grub_strcmp(name, node->src) == 0)
 211         {
 212             if (vlnk)
 213                 *vlnk = 1;
 214             return node->dst;
 215         }
 216         node = node->next;
 217     }
 218
 219     return name;
 220 }
 221
 222 grub_file_t
 223 grub_file_open (const char *name, enum grub_file_type type)
 224 {
 225   int vlnk = 0;
 226   grub_device_t device = 0;
 227   grub_file_t file = 0, last_file = 0;
 228   char *device_name;
 229   const char *file_name;
 230   grub_file_filter_id_t filter;
 231
 232   /* <DESC> : mem:xxx:size:xxx format in chainloader grub_strlen(GRUB_MEMFILE_MEM) */
 233   if (grub_strncmp(name, GRUB_MEMFILE_MEM, 4) == 0) {
 234       return grub_memfile_open(name);
 235   }
 236
 237   if ((g_vlnk_list || g_vtoy_vlnk.srclen) && (type & GRUB_FILE_TYPE_NO_VLNK) == 0)
 238     name = grub_file_get_vlnk(name, &vlnk);
 239
 240   device_name = grub_file_get_device_name (name);
 241   if (grub_errno)
 242     goto fail;
 243
 244   /* Get the file part of NAME.  */
 245   file_name = (name[0] == '(') ? grub_strchr (name, ')') : NULL;
 246   if (file_name)
 247     file_name++;
 248   else
 249     file_name = name;
 250
 251   device = grub_device_open (device_name);
 252   grub_free (device_name);
 253   if (! device)
 254     goto fail;
 255
 256   file = (grub_file_t) grub_zalloc (sizeof (*file));
 257   if (! file)
 258     goto fail;
 259
 260   file->device = device;
 261   file->vlnk = vlnk;
 262
 263   /* In case of relative pathnames and non-Unix systems (like Windows)
 264    * name of host files may not start with `/'. Blocklists for host files
 265    * are meaningless as well (for a start, host disk does not allow any direct
 266    * access - it is just a marker). So skip host disk in this case.
 267    */
 268   if (device->disk && file_name[0] != '/'
 269 #if defined(GRUB_UTIL) || defined(GRUB_MACHINE_EMU)
 270       && grub_strcmp (device->disk->name, "host")
 271 #endif
 272      )
 273     /* This is a block list.  */
 274     file->fs = &grub_fs_blocklist;
 275   else
 276     {
 277       file->fs = grub_fs_probe (device);
 278       if (! file->fs)
 279         goto fail;
 280     }
 281
 282   if ((file->fs->fs_open) (file, file_name) != GRUB_ERR_NONE)
 283     goto fail;
 284
 285   file->name = grub_strdup (name);
 286   grub_errno = GRUB_ERR_NONE;
 287
 288   for (filter = 0; file && filter < ARRAY_SIZE (grub_file_filters);
 289        filter++)
 290     if (grub_file_filters[filter])
 291       {
 292         last_file = file;
 293         file = grub_file_filters[filter] (file, type);
 294         if (file && file != last_file)
 295           {
 296             file->name = grub_strdup (name);
 297             grub_errno = GRUB_ERR_NONE;
 298           }
 299       }
 300   if (!file)
 301     grub_file_close (last_file);
 302
 303   return file;
 304
 305  fail:
 306   if (device)
 307     grub_device_close (device);
 308
 309   /* if (net) grub_net_close (net);  */
 310
 311   grub_free (file);
 312
 313   return 0;
 314 }
 315
 316 grub_disk_read_hook_t grub_file_progress_hook;
 317
 318 grub_ssize_t
 319 grub_file_read (grub_file_t file, void *buf, grub_size_t len)
 320 {
 321   grub_ssize_t res;
 322   grub_disk_read_hook_t read_hook;
 323   void *read_hook_data;
 324
 325   if (file->offset > file->size)
 326     {
 327       grub_error (GRUB_ERR_OUT_OF_RANGE,
 328                   N_("attempt to read past the end of file"));
 329       return -1;
 330     }
 331
 332   if (len == 0)
 333     return 0;
 334
 335   if (len > file->size - file->offset)
 336     len = file->size - file->offset;
 337
 338   /* Prevent an overflow.  */
 339   if ((grub_ssize_t) len < 0)
 340     len >>= 1;
 341
 342   if (len == 0)
 343     return 0;
 344
 345   if (file->name) {
 346     if (grub_strncmp(file->name, GRUB_MEMFILE_MEM, grub_strlen(GRUB_MEMFILE_MEM)) == 0) {
 347       grub_memcpy(buf, (grub_uint8_t *)(file->data) + file->offset, len);
 348       file->offset += len;
 349       return len;
 350     }
 351   }
 352
 353   read_hook = file->read_hook;
 354   read_hook_data = file->read_hook_data;
 355   if (!file->read_hook)
 356     {
 357       file->read_hook = grub_file_progress_hook;
 358       file->read_hook_data = file;
 359       file->progress_offset = file->offset;
 360     }
 361   res = (file->fs->fs_read) (file, buf, len);
 362   file->read_hook = read_hook;
 363   file->read_hook_data = read_hook_data;
 364   if (res > 0)
 365     file->offset += res;
 366
 367   return res;
 368 }
 369
 370 grub_err_t
 371 grub_file_close (grub_file_t file)
 372 {
 373   if (file->fs && file->fs->fs_close)
 374     (file->fs->fs_close) (file);
 375
 376   if (file->device)
 377     grub_device_close (file->device);
 378   grub_free (file->name);
 379   grub_free (file);
 380   return grub_errno;
 381 }
 382
 383 grub_off_t
 384 grub_file_seek (grub_file_t file, grub_off_t offset)
 385 {
 386   grub_off_t old;
 387
 388   if (offset > file->size)
 389     {
 390       grub_error (GRUB_ERR_OUT_OF_RANGE,
 391                   N_("attempt to seek outside of the file"));
 392       return -1;
 393     }
 394
 395   old = file->offset;
 396   file->offset = offset;
 397
 398   return old;
 399 }