cramfsck.c

制作cramfs文件系统的工具

		die(FSCK_UNCORRECTED, 0, "decompression error %p(%d): %s",
		    zError(err), src, len);
	}
	return stream.total_out;
}

static void do_uncompress(char *path, int fd, unsigned long offset, unsigned long size)
{
	unsigned long curr = offset + 4 * ((size + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE);

	do {
		unsigned long out = PAGE_CACHE_SIZE;
		unsigned long next = *(u32 *) romfs_read(offset);

		if (next > end_data) {
			end_data = next;
		}

		offset += 4;
		if (curr == next) {
			if (opt_verbose > 1) {
				printf("  hole at %ld (%d)\n", curr, PAGE_CACHE_SIZE);
			}
			if (size < PAGE_CACHE_SIZE)
				out = size;
			memset(outbuffer, 0x00, out);
		}
		else {
			if (opt_verbose > 1) {
				printf("  uncompressing block at %ld to %ld (%ld)\n", curr, next, next - curr);
			}
			out = uncompress_block(romfs_read(curr), next - curr);
		}
		if (size >= PAGE_CACHE_SIZE) {
			if (out != PAGE_CACHE_SIZE) {
				die(FSCK_UNCORRECTED, 0, "non-block (%ld) bytes", out);
			}
		} else {
			if (out != size) {
				die(FSCK_UNCORRECTED, 0, "non-size (%ld vs %ld) bytes", out, size);
			}
		}
		size -= out;
		if (opt_extract) {
			if (write(fd, outbuffer, out) < 0) {
				die(FSCK_ERROR, 1, "write failed: %s", path);
			}
		}
		curr = next;
	} while (size);
}

static void change_file_status(char *path, struct cramfs_inode *i)
{
	struct utimbuf epoch = { 0, 0 };

	if (euid == 0) {
		if (lchown(path, i->uid, i->gid) < 0) {
			die(FSCK_ERROR, 1, "lchown failed: %s", path);
		}
		if (S_ISLNK(i->mode))
			return;
		if ((S_ISUID | S_ISGID) & i->mode) {
			if (chmod(path, i->mode) < 0) {
				die(FSCK_ERROR, 1, "chown failed: %s", path);
			}
		}
	}
	if (S_ISLNK(i->mode))
		return;
	if (utime(path, &epoch) < 0) {
		die(FSCK_ERROR, 1, "utime failed: %s", path);
	}
}

static void do_directory(char *path, struct cramfs_inode *i)
{
	int pathlen = strlen(path);
	int count = i->size;
	unsigned long offset = i->offset << 2;
	char *newpath = malloc(pathlen + 256);

	if (!newpath) {
		die(FSCK_ERROR, 1, "malloc failed");
	}
	if (offset == 0 && count != 0) {
		die(FSCK_UNCORRECTED, 0, "directory inode has zero offset and non-zero size: %s", path);
	}
	if (offset != 0 && offset < start_dir) {
		start_dir = offset;
	}
	/* TODO: Do we need to check end_dir for empty case? */
	memcpy(newpath, path, pathlen);
	newpath[pathlen] = '/';
	pathlen++;
	if (opt_verbose) {
		print_node('d', i, path);
	}
	if (opt_extract) {
		if (mkdir(path, i->mode) < 0) {
			die(FSCK_ERROR, 1, "mkdir failed: %s", path);
		}
		change_file_status(path, i);
	}
	while (count > 0) {
		struct cramfs_inode *child = iget(offset);
		int size;
		int newlen = child->namelen << 2;

		size = sizeof(struct cramfs_inode) + newlen;
		count -= size;

		offset += sizeof(struct cramfs_inode);

		memcpy(newpath + pathlen, romfs_read(offset), newlen);
		newpath[pathlen + newlen] = 0;
		if (newlen == 0) {
			die(FSCK_UNCORRECTED, 0, "filename length is zero");
		}
		if ((pathlen + newlen) - strlen(newpath) > 3) {
			die(FSCK_UNCORRECTED, 0, "bad filename length");
		}
		expand_fs(newpath, child);

		offset += newlen;

		if (offset <= start_dir) {
			die(FSCK_UNCORRECTED, 0, "bad inode offset");
		}
		if (offset > end_dir) {
			end_dir = offset;
		}
		iput(child); /* free(child) */
	}
	free(newpath);
}

static void do_file(char *path, struct cramfs_inode *i)
{
	unsigned long offset = i->offset << 2;
	int fd = 0;

	if (offset == 0 && i->size != 0) {
		die(FSCK_UNCORRECTED, 0, "file inode has zero offset and non-zero size");
	}
	if (i->size == 0 && offset != 0) {
		die(FSCK_UNCORRECTED, 0, "file inode has zero size and non-zero offset");
	}
	if (offset != 0 && offset < start_data) {
		start_data = offset;
	}
	if (opt_verbose) {
		print_node('f', i, path);
	}
	if (opt_extract) {
		fd = open(path, O_WRONLY | O_CREAT | O_TRUNC, i->mode);
		if (fd < 0) {
			die(FSCK_ERROR, 1, "open failed: %s", path);
		}
	}
	if (i->size) {
		do_uncompress(path, fd, offset, i->size);
	}
	if (opt_extract) {
		close(fd);
		change_file_status(path, i);
	}
}

static void do_symlink(char *path, struct cramfs_inode *i)
{
	unsigned long offset = i->offset << 2;
	unsigned long curr = offset + 4;
	unsigned long next = *(u32 *) romfs_read(offset);
	unsigned long size;

	if (offset == 0) {
		die(FSCK_UNCORRECTED, 0, "symbolic link has zero offset");
	}
	if (i->size == 0) {
		die(FSCK_UNCORRECTED, 0, "symbolic link has zero size");
	}

	if (offset < start_data) {
		start_data = offset;
	}
	if (next > end_data) {
		end_data = next;
	}

	size = uncompress_block(romfs_read(curr), next - curr);
	if (size != i->size) {
		die(FSCK_UNCORRECTED, 0, "size error in symlink: %s", path);
	}
	outbuffer[size] = 0;
	if (opt_verbose) {
		char *str;

		asprintf(&str, "%s -> %s", path, outbuffer);
		print_node('l', i, str);
		if (opt_verbose > 1) {
			printf("  uncompressing block at %ld to %ld (%ld)\n", curr, next, next - curr);
		}
		free(str);
	}
	if (opt_extract) {
		if (symlink(outbuffer, path) < 0) {
			die(FSCK_ERROR, 1, "symlink failed: %s", path);
		}
		change_file_status(path, i);
	}
}

static void do_special_inode(char *path, struct cramfs_inode *i)
{
	dev_t devtype = 0;
	char type;

	if (i->offset) {	/* no need to shift offset */
		die(FSCK_UNCORRECTED, 0, "special file has non-zero offset: %s", path);
	}
	if (S_ISCHR(i->mode)) {
		devtype = i->size;
		type = 'c';
	}
	else if (S_ISBLK(i->mode)) {
		devtype = i->size;
		type = 'b';
	}
	else if (S_ISFIFO(i->mode)) {
		if (i->size != 0) {
			die(FSCK_UNCORRECTED, 0, "fifo has non-zero size: %s", path);
		}
		type = 'p';
	}
	else if (S_ISSOCK(i->mode)) {
		if (i->size != 0) {
			die(FSCK_UNCORRECTED, 0, "socket has non-zero size: %s", path);
		}
		type = 's';
	}
	else {
		die(FSCK_UNCORRECTED, 0, "bogus mode: %s (%o)", path, i->mode);
		return;		/* not reached */
	}

	if (opt_verbose) {
		print_node(type, i, path);
	}

	if (opt_extract) {
		if (mknod(path, i->mode, devtype) < 0) {
			die(FSCK_ERROR, 1, "mknod failed: %s", path);
		}
		change_file_status(path, i);
	}
}

static void expand_fs(char *path, struct cramfs_inode *inode)
{
	if (S_ISDIR(inode->mode)) {
		do_directory(path, inode);
	}
	else if (S_ISREG(inode->mode)) {
		do_file(path, inode);
	}
	else if (S_ISLNK(inode->mode)) {
		do_symlink(path, inode);
	}
	else {
		do_special_inode(path, inode);
	}
}

static void test_fs(int start)
{
	struct cramfs_inode *root;

	root = read_super();
	umask(0);
	euid = geteuid();
	stream.next_in = NULL;
	stream.avail_in = 0;
	inflateInit(&stream);
	expand_fs(extract_dir, root);
	inflateEnd(&stream);
	if (start_data != ~0UL) {
		if (start_data < (sizeof(struct cramfs_super) + start)) {
			die(FSCK_UNCORRECTED, 0, "directory data start (%ld) < sizeof(struct cramfs_super) + start (%ld)", start_data, sizeof(struct cramfs_super) + start);
		}
		if (end_dir != start_data) {
			die(FSCK_UNCORRECTED, 0, "directory data end (%ld) != file data start (%ld)", end_dir, start_data);
		}
	}
	if (super.flags & CRAMFS_FLAG_FSID_VERSION_2) {
		if (end_data > super.size) {
			die(FSCK_UNCORRECTED, 0, "invalid file data offset");
		}
	}
	iput(root);		/* free(root) */
}
#endif /* INCLUDE_FS_TESTS */

int main(int argc, char **argv)
{
	int c;			/* for getopt */
	int start = 0;
	size_t length;

	if (argc)
		progname = argv[0];

	/* command line options */
	while ((c = getopt(argc, argv, "hx:v")) != EOF) {
		switch (c) {
		case 'h':
			usage(FSCK_OK);
		case 'x':
#ifdef INCLUDE_FS_TESTS
			opt_extract = 1;
			extract_dir = optarg;
			break;
#else /* not INCLUDE_FS_TESTS */
			die(FSCK_USAGE, 0, "compiled without -x support");
#endif /* not INCLUDE_FS_TESTS */
		case 'v':
			opt_verbose++;
			break;
		}
	}

	if ((argc - optind) != 1)
		usage(FSCK_USAGE);
	filename = argv[optind];

	test_super(&start, &length);
	test_crc(start);
#ifdef INCLUDE_FS_TESTS
	test_fs(start);
#endif /* INCLUDE_FS_TESTS */

	if (opt_verbose) {
		printf("%s: OK\n", filename);
	}

	exit(FSCK_OK);
}

/*
 * Local variables:
 * c-file-style: "linux"
 * End:
 */