SQUASHFS/squashfs-tools-4.4/squashfs-tools/unsquash-123.c

   1 /*
   2  * Unsquash a squashfs filesystem.  This is a highly compressed read only
   3  * filesystem.
   4  *
   5  * Copyright (c) 2019
   6  * Phillip Lougher <phillip@squashfs.org.uk>
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License
  10  * as published by the Free Software Foundation; either version 2,
  11  * or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  21  *
  22  * unsquash-123.c
  23  *
  24  * Helper functions used by unsquash-1, unsquash-2 and unsquash-3.
  25  */
  26
  27 #include "unsquashfs.h"
  28 #include "squashfs_compat.h"
  29
  30 int read_ids(int ids, long long start, long long end, unsigned int **id_table)
  31 {
  32         /* Note on overflow limits:
  33          * Size of ids is 2^8
  34          * Max length is 2^8*4 or 1024
  35          */
  36         int res;
  37         int length = ids * sizeof(unsigned int);
  38
  39         /*
  40          * The size of the index table (length bytes) should match the
  41          * table start and end points
  42          */
  43         if(length != (end - start)) {
  44                 ERROR("read_ids: Bad inode count in super block\n");
  45                 return FALSE;
  46         }
  47
  48         TRACE("read_ids: no_ids %d\n", ids);
  49
  50         *id_table = malloc(length);
  51         if(*id_table == NULL) {
  52                 ERROR("read_ids: failed to allocate uid/gid table\n");
  53                 return FALSE;
  54         }
  55
  56         if(swap) {
  57                 unsigned int *sid_table = malloc(length);
  58
  59                 if(sid_table == NULL) {
  60                         ERROR("read_ids: failed to allocate uid/gid table\n");
  61                         return FALSE;
  62                 }
  63
  64                 res = read_fs_bytes(fd, start, length, sid_table);
  65                 if(res == FALSE) {
  66                         ERROR("read_ids: failed to read uid/gid table"
  67                                 "\n");
  68                         free(sid_table);
  69                         return FALSE;
  70                 }
  71                 SQUASHFS_SWAP_INTS_3((*id_table), sid_table, ids);
  72                 free(sid_table);
  73         } else {
  74                 res = read_fs_bytes(fd, start, length, *id_table);
  75                 if(res == FALSE) {
  76                         ERROR("read_ids: failed to read uid/gid table"
  77                                 "\n");
  78                         return FALSE;
  79                 }
  80         }
  81
  82         return TRUE;
  83 }