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_vlnk_list;
 118
 119 int grub_file_is_vlnk_suffix(const char *name, int len)
 120 {
 121     grub_uint32_t suffix;
 122
 123     if (len > 9)
 124     {
 125         suffix = *(grub_uint32_t *)(name + len - 4);
 126         if (grub_strncmp(name + len - 9, ".vlnk.", 6) == 0)
 127         {
 128             /* .iso .wim .img .vhd .efi .dat */
 129             if (suffix == 0x6F73692E || suffix == 0x6D69772E ||
 130                 suffix == 0x676D692E || suffix == 0x6468762E ||
 131                 suffix == 0x6966652E || suffix == 0x7461642E)
 132             {
 133                 return 1;
 134             }
 135         }
 136         else if (len > 10 && grub_strncmp(name + len - 10, ".vlnk.", 6) == 0)
 137         {
 138             /* vhdx vtoy */
 139             if (suffix == 0x78646876 || suffix == 0x796F7476)
 140             {
 141                 return 1;
 142             }
 143         }
 144     }
 145
 146     return 0;
 147 }
 148
 149 int grub_file_add_vlnk(const char *src, const char *dst)
 150 {
 151     grub_vlnk *node = NULL;
 152
 153     if (src && dst)
 154     {
 155         node = grub_zalloc(sizeof(grub_vlnk));
 156         if (node)
 157         {
 158             node->srclen = (int)grub_strlen(src);
 159             grub_strncpy(node->src, src, sizeof(node->src) - 1);
 160             grub_strncpy(node->dst, dst, sizeof(node->dst) - 1);
 161
 162             node->next = g_vlnk_list;
 163             g_vlnk_list = node;
 164             return 0;
 165         }
 166     }
 167
 168     return 1;
 169 }
 170
 171 const char *grub_file_get_vlnk(const char *name, int *vlnk)
 172 {
 173     int len;
 174     grub_vlnk *node = g_vlnk_list;
 175
 176     len = grub_strlen(name);
 177     if (!grub_file_is_vlnk_suffix(name, len))
 178     {
 179         return name;
 180     }
 181
 182     while (node)
 183     {
 184         if (node->srclen == len && grub_strcmp(name, node->src) == 0)
 185         {
 186             *vlnk = 1;
 187             return node->dst;
 188         }
 189         node = node->next;
 190     }
 191
 192     return name;
 193 }
 194
 195 grub_file_t
 196 grub_file_open (const char *name, enum grub_file_type type)
 197 {
 198   int vlnk = 0;
 199   grub_device_t device = 0;
 200   grub_file_t file = 0, last_file = 0;
 201   char *device_name;
 202   const char *file_name;
 203   grub_file_filter_id_t filter;
 204
 205   /* <DESC> : mem:xxx:size:xxx format in chainloader grub_strlen(GRUB_MEMFILE_MEM) */
 206   if (grub_strncmp(name, GRUB_MEMFILE_MEM, 4) == 0) {
 207       return grub_memfile_open(name);
 208   }
 209
 210   if (g_vlnk_list && (type & GRUB_FILE_TYPE_NO_VLNK) == 0)
 211     name = grub_file_get_vlnk(name, &vlnk);
 212
 213   device_name = grub_file_get_device_name (name);
 214   if (grub_errno)
 215     goto fail;
 216
 217   /* Get the file part of NAME.  */
 218   file_name = (name[0] == '(') ? grub_strchr (name, ')') : NULL;
 219   if (file_name)
 220     file_name++;
 221   else
 222     file_name = name;
 223
 224   device = grub_device_open (device_name);
 225   grub_free (device_name);
 226   if (! device)
 227     goto fail;
 228
 229   file = (grub_file_t) grub_zalloc (sizeof (*file));
 230   if (! file)
 231     goto fail;
 232
 233   file->device = device;
 234   file->vlnk = vlnk;
 235
 236   /* In case of relative pathnames and non-Unix systems (like Windows)
 237    * name of host files may not start with `/'. Blocklists for host files
 238    * are meaningless as well (for a start, host disk does not allow any direct
 239    * access - it is just a marker). So skip host disk in this case.
 240    */
 241   if (device->disk && file_name[0] != '/'
 242 #if defined(GRUB_UTIL) || defined(GRUB_MACHINE_EMU)
 243       && grub_strcmp (device->disk->name, "host")
 244 #endif
 245      )
 246     /* This is a block list.  */
 247     file->fs = &grub_fs_blocklist;
 248   else
 249     {
 250       file->fs = grub_fs_probe (device);
 251       if (! file->fs)
 252         goto fail;
 253     }
 254
 255   if ((file->fs->fs_open) (file, file_name) != GRUB_ERR_NONE)
 256     goto fail;
 257
 258   file->name = grub_strdup (name);
 259   grub_errno = GRUB_ERR_NONE;
 260
 261   for (filter = 0; file && filter < ARRAY_SIZE (grub_file_filters);
 262        filter++)
 263     if (grub_file_filters[filter])
 264       {
 265         last_file = file;
 266         file = grub_file_filters[filter] (file, type);
 267         if (file && file != last_file)
 268           {
 269             file->name = grub_strdup (name);
 270             grub_errno = GRUB_ERR_NONE;
 271           }
 272       }
 273   if (!file)
 274     grub_file_close (last_file);
 275
 276   return file;
 277
 278  fail:
 279   if (device)
 280     grub_device_close (device);
 281
 282   /* if (net) grub_net_close (net);  */
 283
 284   grub_free (file);
 285
 286   return 0;
 287 }
 288
 289 grub_disk_read_hook_t grub_file_progress_hook;
 290
 291 grub_ssize_t
 292 grub_file_read (grub_file_t file, void *buf, grub_size_t len)
 293 {
 294   grub_ssize_t res;
 295   grub_disk_read_hook_t read_hook;
 296   void *read_hook_data;
 297
 298   if (file->offset > file->size)
 299     {
 300       grub_error (GRUB_ERR_OUT_OF_RANGE,
 301                   N_("attempt to read past the end of file"));
 302       return -1;
 303     }
 304
 305   if (len == 0)
 306     return 0;
 307
 308   if (len > file->size - file->offset)
 309     len = file->size - file->offset;
 310
 311   /* Prevent an overflow.  */
 312   if ((grub_ssize_t) len < 0)
 313     len >>= 1;
 314
 315   if (len == 0)
 316     return 0;
 317
 318   if (grub_strncmp(file->name, GRUB_MEMFILE_MEM, grub_strlen(GRUB_MEMFILE_MEM)) == 0) {
 319       grub_memcpy(buf, (grub_uint8_t *)(file->data) + file->offset, len);
 320       file->offset += len;
 321       return len;
 322   }
 323
 324   read_hook = file->read_hook;
 325   read_hook_data = file->read_hook_data;
 326   if (!file->read_hook)
 327     {
 328       file->read_hook = grub_file_progress_hook;
 329       file->read_hook_data = file;
 330       file->progress_offset = file->offset;
 331     }
 332   res = (file->fs->fs_read) (file, buf, len);
 333   file->read_hook = read_hook;
 334   file->read_hook_data = read_hook_data;
 335   if (res > 0)
 336     file->offset += res;
 337
 338   return res;
 339 }
 340
 341 grub_err_t
 342 grub_file_close (grub_file_t file)
 343 {
 344   if (file->fs && file->fs->fs_close)
 345     (file->fs->fs_close) (file);
 346
 347   if (file->device)
 348     grub_device_close (file->device);
 349   grub_free (file->name);
 350   grub_free (file);
 351   return grub_errno;
 352 }
 353
 354 grub_off_t
 355 grub_file_seek (grub_file_t file, grub_off_t offset)
 356 {
 357   grub_off_t old;
 358
 359   if (offset > file->size)
 360     {
 361       grub_error (GRUB_ERR_OUT_OF_RANGE,
 362                   N_("attempt to seek outside of the file"));
 363       return -1;
 364     }
 365
 366   old = file->offset;
 367   file->offset = offset;
 368
 369   return old;
 370 }