libfstools/snapshot.h

   1 /*
   2  * Copyright (C) 2014 John Crispin <blogic@openwrt.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU Lesser General Public License version 2.1
   6  * as published by the Free Software Foundation
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #ifndef _SNAPSHOT_H__
  15 #define _SNAPSHOT_H__
  16
  17 #define PATH_MAX        256
  18 #define OWRT            0x4f575254
  19 #define DATA            0x44415441
  20 #define CONF            0x434f4e46
  21
  22 struct file_header {
  23         uint32_t magic;
  24         uint32_t type;
  25         uint32_t seq;
  26         uint32_t length;
  27         uint32_t md5[4];
  28 };
  29
  30 static inline int
  31 is_config(struct file_header *h)
  32 {
  33         return ((h->magic == OWRT) && (h->type == CONF));
  34 }
  35
  36 static inline int
  37 valid_file_size(int fs)
  38 {
  39         if ((fs > 8 * 1024 * 1204) || (fs <= 0))
  40                 return -1;
  41
  42         return 0;
  43 }
  44
  45 static inline void
  46 hdr_to_be32(struct file_header *hdr)
  47 {
  48         uint32_t *h = (uint32_t *) hdr;
  49         int i;
  50
  51         for (i = 0; i < sizeof(struct file_header) / sizeof(uint32_t); i++)
  52                 h[i] = cpu_to_be32(h[i]);
  53 }
  54
  55 static inline void
  56 be32_to_hdr(struct file_header *hdr)
  57 {
  58         uint32_t *h = (uint32_t *) hdr;
  59         int i;
  60
  61         for (i = 0; i < sizeof(struct file_header) / sizeof(uint32_t); i++)
  62                 h[i] = be32_to_cpu(h[i]);
  63 }
  64
  65 static inline int
  66 pad_file_size(struct volume *v, int size)
  67 {
  68         int mod;
  69
  70         size += sizeof(struct file_header);
  71         mod = size % v->block_size;
  72         if (mod) {
  73                 size -= mod;
  74                 size += v->block_size;
  75         }
  76
  77         return size;
  78 }
  79
  80 int verify_file_hash(char *file, uint32_t *hash);
  81 int snapshot_next_free(struct volume *v, uint32_t *seq);
  82 int config_find(struct volume *v, struct file_header *conf, struct file_header *sentinel);
  83 int snapshot_write_file(struct volume *v, int block, char *file, uint32_t seq, uint32_t type);
  84 int snapshot_read_file(struct volume *v, int block, char *file, uint32_t type);
  85 int sentinel_write(struct volume *v, uint32_t _seq);
  86 int volatile_write(struct volume *v, uint32_t _seq);
  87
  88 #endif