1 files changed, 118 insertions, 0 deletions
diff --git a/nandroid/unyaffs.c b/nandroid/unyaffs.c
new file mode 100644
index 0000000..aa8a735
--- /dev/null
+++ b/nandroid/unyaffs.c
@@ -0,0 +1,118 @@
+/*
+ * 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;
+}