Add utility to turn a squashfs image into a POSIX tar archvie

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

1 files changed, 208 insertions, 0 deletions

diff --git a/tar/sqfs2tar.c b/tar/sqfs2tar.c
new file mode 100644
index 0000000..f7f7e71
--- /dev/null
+++ b/tar/sqfs2tar.c
@@ -0,0 +1,208 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+#include "meta_reader.h"
+#include "data_reader.h"
+#include "highlevel.h"
+#include "compress.h"
+#include "fstree.h"
+#include "util.h"
+#include "tar.h"
+
+#include <getopt.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+
+static struct option long_opts[] = {
+	{ "help", no_argument, NULL, 'h' },
+	{ "version", no_argument, NULL, 'V' },
+};
+
+static const char *short_opts = "hV";
+
+static const char *usagestr =
+"Usage: sqfs2tar [OPTIONS...] <sqfsfile>\n"
+"\n"
+"Read an input squashfs archive and turn it into a tar archive, written\n"
+"to stdout.\n"
+"\n"
+"Possible options:\n"
+"\n"
+"  --help, -h                Print help text and exit.\n"
+"  --version, -V             Print version information and exit.\n"
+"\n"
+"Examples:\n"
+"\n"
+"\tsqfs2tar rootfs.sqfs > rootfs.tar\n"
+"\tsqfs2tar rootfs.sqfs | gzip > rootfs.tar.gz\n"
+"\tsqfs2tar rootfs.sqfs | xz > rootfs.tar.xz\n"
+"\n";
+
+static const char *filename;
+
+static void process_args(int argc, char **argv)
+{
+	int i;
+
+	for (;;) {
+		i = getopt_long(argc, argv, short_opts, long_opts, NULL);
+		if (i == -1)
+			break;
+
+		switch (i) {
+		case 'h':
+			fputs(usagestr, stdout);
+			exit(EXIT_SUCCESS);
+		case 'V':
+			print_version();
+			exit(EXIT_SUCCESS);
+		default:
+			goto fail_arg;
+		}
+	}
+
+	if (optind >= argc) {
+		fputs("Missing argument: squashfs image\n", stderr);
+		goto fail_arg;
+	}
+
+	filename = argv[optind++];
+
+	if (optind < argc) {
+		fputs("Unknown extra arguments\n", stderr);
+		goto fail_arg;
+	}
+	return;
+fail_arg:
+	fputs("Try `sqfs2tar --help' for more information.\n", stderr);
+	exit(EXIT_FAILURE);
+}
+
+static int terminate_archive(void)
+{
+	char buffer[1024];
+	ssize_t ret;
+
+	memset(buffer, '\0', sizeof(buffer));
+
+	ret = write_retry(STDOUT_FILENO, buffer, sizeof(buffer));
+
+	if (ret < 0) {
+		perror("adding archive terminator");
+		return -1;
+	}
+
+	if ((size_t)ret < sizeof(buffer)) {
+		fputs("adding archive terminator: truncated write\n", stderr);
+		return -1;
+	}
+
+	return 0;
+}
+
+static int write_tree_dfs(fstree_t *fs, tree_node_t *n, data_reader_t *data)
+{
+	char *name;
+	int ret;
+
+	if (n->parent != NULL || !S_ISDIR(n->mode)) {
+		name = fstree_get_path(n);
+		if (name == NULL) {
+			perror("resolving tree node path");
+			return -1;
+		}
+
+		assert(canonicalize_name(name) == 0);
+
+		ret = write_tar_header(STDOUT_FILENO, fs, n, name);
+		free(name);
+
+		if (ret < 0)
+			return -1;
+		if (ret > 0)
+			return 0;
+
+		if (S_ISREG(n->mode)) {
+			if (data_reader_dump_file(data, n->data.file,
+						  STDOUT_FILENO)) {
+				return -1;
+			}
+
+			if (padd_file(STDOUT_FILENO, n->data.file->size, 512))
+				return -1;
+		}
+	}
+
+	if (S_ISDIR(n->mode)) {
+		for (n = n->data.dir->children; n != NULL; n = n->next) {
+			if (write_tree_dfs(fs, n, data))
+				return -1;
+		}
+	}
+
+	return 0;
+}
+
+int main(int argc, char **argv)
+{
+	data_reader_t *data = NULL;
+	int status = EXIT_FAILURE;
+	sqfs_super_t super;
+	compressor_t *cmp;
+	fstree_t fs;
+	int sqfsfd;
+
+	process_args(argc, argv);
+
+	sqfsfd = open(filename, O_RDONLY);
+	if (sqfsfd < 0) {
+		perror(filename);
+		return EXIT_FAILURE;
+	}
+
+	if (sqfs_super_read(&super, sqfsfd))
+		goto out_fd;
+
+	if (!compressor_exists(super.compression_id)) {
+		fputs("Image uses a compressor that has not been built in\n",
+		      stderr);
+		goto out_fd;
+	}
+
+	cmp = compressor_create(super.compression_id, false,
+				super.block_size, NULL);
+	if (cmp == NULL)
+		goto out_fd;
+
+	if (super.flags & SQFS_FLAG_COMPRESSOR_OPTIONS) {
+		if (cmp->read_options(cmp, sqfsfd))
+			goto out_cmp;
+	}
+
+	if (deserialize_fstree(&fs, &super, cmp, sqfsfd, 0))
+		goto out_cmp;
+
+	data = data_reader_create(sqfsfd, &super, cmp);
+	if (data == NULL)
+		goto out_fs;
+
+	if (write_tree_dfs(&fs, fs.root, data))
+		goto out_data;
+
+	if (terminate_archive())
+		goto out_data;
+
+	status = EXIT_SUCCESS;
+out_data:
+	data_reader_destroy(data);
+out_fs:
+	fstree_cleanup(&fs);
+out_cmp:
+	cmp->destroy(cmp);
+out_fd:
+	close(sqfsfd);
+	return status;
+}