2010-02-20 15:59:06 -08:00

119 lines
2.8 KiB
C

/*
* unyaffs: extract files from yaffs2 file system image to current directory
*
* Created by Kai Wei <kai.wei.cn@gmail.com>
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "unyaffs.h"
#define CHUNK_SIZE 2048
#define SPARE_SIZE 64
#define MAX_OBJECTS 10000
#define YAFFS_OBJECTID_ROOT 1
unsigned char data[CHUNK_SIZE + SPARE_SIZE];
unsigned char *chunk_data = data;
unsigned char *spare_data = data + CHUNK_SIZE;
int img_file;
char *obj_list[MAX_OBJECTS];
void process_chunk()
{
int out_file, remain, s;
char *full_path_name;
yaffs_PackedTags2 *pt = (yaffs_PackedTags2 *)spare_data;
if (pt->t.byteCount == 0xffff) { //a new object
yaffs_ObjectHeader *oh = (yaffs_ObjectHeader *)malloc(sizeof(yaffs_ObjectHeader));
memcpy(oh, chunk_data, sizeof(yaffs_ObjectHeader));
full_path_name = (char *)malloc(strlen(oh->name) + strlen(obj_list[oh->parentObjectId]) + 2);
if (full_path_name == NULL) {
perror("malloc full path name\n");
}
strcpy(full_path_name, obj_list[oh->parentObjectId]);
strcat(full_path_name, "/");
strcat(full_path_name, oh->name);
obj_list[pt->t.objectId] = full_path_name;
switch(oh->type) {
case YAFFS_OBJECT_TYPE_FILE:
remain = oh->fileSize;
out_file = creat(full_path_name, oh->yst_mode);
while(remain > 0) {
if (read_chunk())
return -1;
s = (remain < pt->t.byteCount) ? remain : pt->t.byteCount;
if (write(out_file, chunk_data, s) == -1)
return -1;
remain -= s;
}
close(out_file);
break;
case YAFFS_OBJECT_TYPE_SYMLINK:
symlink(oh->alias, full_path_name);
break;
case YAFFS_OBJECT_TYPE_DIRECTORY:
mkdir(full_path_name, 0777);
break;
case YAFFS_OBJECT_TYPE_HARDLINK:
link(obj_list[oh->equivalentObjectId], full_path_name);
break;
}
}
}
int read_chunk()
{
ssize_t s;
int ret = -1;
memset(chunk_data, 0xff, sizeof(chunk_data));
s = read(img_file, data, CHUNK_SIZE + SPARE_SIZE);
if (s == -1) {
perror("read image file\n");
} else if (s == 0) {
printf("end of image\n");
} else if ((s == (CHUNK_SIZE + SPARE_SIZE))) {
ret = 0;
} else {
fprintf(stderr, "broken image file\n");
}
return ret;
}
int main(int argc, char **argv)
{
if (argc != 2) {
printf("Usage: unyaffs image_file_name\n");
exit(1);
}
img_file = open(argv[1], O_RDONLY);
if (img_file == -1) {
printf("open image file failed\n");
exit(1);
}
obj_list[YAFFS_OBJECTID_ROOT] = ".";
while(1) {
if (read_chunk() == -1)
break;
process_chunk();
}
close(img_file);
return 0;
}