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         *vlnk = 1;
 204         return g_vtoy_vlnk.dst;
 205     }
 206
 207     while (node)
 208     {
 209         if (node->srclen == len && grub_strcmp(name, node->src) == 0)
 210         {
 211             *vlnk = 1;
 212             return node->dst;
 213         }
 214         node = node->next;
 215     }
 216
 217     return name;
 218 }
 219
 220 grub_file_t
 221 grub_file_open (const char *name, enum grub_file_type type)
 222 {
 223   int vlnk = 0;
 224   grub_device_t device = 0;
 225   grub_file_t file = 0, last_file = 0;
 226   char *device_name;
 227   const char *file_name;
 228   grub_file_filter_id_t filter;
 229
 230   /* <DESC> : mem:xxx:size:xxx format in chainloader grub_strlen(GRUB_MEMFILE_MEM) */
 231   if (grub_strncmp(name, GRUB_MEMFILE_MEM, 4) == 0) {
 232       return grub_memfile_open(name);
 233   }
 234
 235   if ((g_vlnk_list || g_vtoy_vlnk.srclen) && (type & GRUB_FILE_TYPE_NO_VLNK) == 0)
 236     name = grub_file_get_vlnk(name, &vlnk);
 237
 238   device_name = grub_file_get_device_name (name);
 239   if (grub_errno)
 240     goto fail;
 241
 242   /* Get the file part of NAME.  */
 243   file_name = (name[0] == '(') ? grub_strchr (name, ')') : NULL;
 244   if (file_name)
 245     file_name++;
 246   else
 247     file_name = name;
 248
 249   device = grub_device_open (device_name);
 250   grub_free (device_name);
 251   if (! device)
 252     goto fail;
 253
 254   file = (grub_file_t) grub_zalloc (sizeof (*file));
 255   if (! file)
 256     goto fail;
 257
 258   file->device = device;
 259   file->vlnk = vlnk;
 260
 261   /* In case of relative pathnames and non-Unix systems (like Windows)
 262    * name of host files may not start with `/'. Blocklists for host files
 263    * are meaningless as well (for a start, host disk does not allow any direct
 264    * access - it is just a marker). So skip host disk in this case.
 265    */
 266   if (device->disk && file_name[0] != '/'
 267 #if defined(GRUB_UTIL) || defined(GRUB_MACHINE_EMU)
 268       && grub_strcmp (device->disk->name, "host")
 269 #endif
 270      )
 271     /* This is a block list.  */
 272     file->fs = &grub_fs_blocklist;
 273   else
 274     {
 275       file->fs = grub_fs_probe (device);
 276       if (! file->fs)
 277         goto fail;
 278     }
 279
 280   if ((file->fs->fs_open) (file, file_name) != GRUB_ERR_NONE)
 281     goto fail;
 282
 283   file->name = grub_strdup (name);
 284   grub_errno = GRUB_ERR_NONE;
 285
 286   for (filter = 0; file && filter < ARRAY_SIZE (grub_file_filters);
 287        filter++)
 288     if (grub_file_filters[filter])
 289       {
 290         last_file = file;
 291         file = grub_file_filters[filter] (file, type);
 292         if (file && file != last_file)
 293           {
 294             file->name = grub_strdup (name);
 295             grub_errno = GRUB_ERR_NONE;
 296           }
 297       }
 298   if (!file)
 299     grub_file_close (last_file);
 300
 301   return file;
 302
 303  fail:
 304   if (device)
 305     grub_device_close (device);
 306
 307   /* if (net) grub_net_close (net);  */
 308
 309   grub_free (file);
 310
 311   return 0;
 312 }
 313
 314 grub_disk_read_hook_t grub_file_progress_hook;
 315
 316 grub_ssize_t
 317 grub_file_read (grub_file_t file, void *buf, grub_size_t len)
 318 {
 319   grub_ssize_t res;
 320   grub_disk_read_hook_t read_hook;
 321   void *read_hook_data;
 322
 323   if (file->offset > file->size)
 324     {
 325       grub_error (GRUB_ERR_OUT_OF_RANGE,
 326                   N_("attempt to read past the end of file"));
 327       return -1;
 328     }
 329
 330   if (len == 0)
 331     return 0;
 332
 333   if (len > file->size - file->offset)
 334     len = file->size - file->offset;
 335
 336   /* Prevent an overflow.  */
 337   if ((grub_ssize_t) len < 0)
 338     len >>= 1;
 339
 340   if (len == 0)
 341     return 0;
 342
 343   if (grub_strncmp(file->name, GRUB_MEMFILE_MEM, grub_strlen(GRUB_MEMFILE_MEM)) == 0) {
 344       grub_memcpy(buf, (grub_uint8_t *)(file->data) + file->offset, len);
 345       file->offset += len;
 346       return len;
 347   }
 348
 349   read_hook = file->read_hook;
 350   read_hook_data = file->read_hook_data;
 351   if (!file->read_hook)
 352     {
 353       file->read_hook = grub_file_progress_hook;
 354       file->read_hook_data = file;
 355       file->progress_offset = file->offset;
 356     }
 357   res = (file->fs->fs_read) (file, buf, len);
 358   file->read_hook = read_hook;
 359   file->read_hook_data = read_hook_data;
 360   if (res > 0)
 361     file->offset += res;
 362
 363   return res;
 364 }
 365
 366 grub_err_t
 367 grub_file_close (grub_file_t file)
 368 {
 369   if (file->fs && file->fs->fs_close)
 370     (file->fs->fs_close) (file);
 371
 372   if (file->device)
 373     grub_device_close (file->device);
 374   grub_free (file->name);
 375   grub_free (file);
 376   return grub_errno;
 377 }
 378
 379 grub_off_t
 380 grub_file_seek (grub_file_t file, grub_off_t offset)
 381 {
 382   grub_off_t old;
 383
 384   if (offset > file->size)
 385     {
 386       grub_error (GRUB_ERR_OUT_OF_RANGE,
 387                   N_("attempt to seek outside of the file"));
 388       return -1;
 389     }
 390
 391   old = file->offset;
 392   file->offset = offset;
 393
 394   return old;
 395 }