unsquashfs: add argument processing, file listing parameter

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

1 files changed, 122 insertions, 13 deletions

diff --git a/unpack/unsquashfs.c b/unpack/unsquashfs.c
index d332dee..b253bae 100644
--- a/unpack/unsquashfs.c
+++ b/unpack/unsquashfs.c
@@ -1,28 +1,119 @@
 /* SPDX-License-Identifier: GPL-3.0-or-later */
 #include "unsquashfs.h"
 
+static struct option long_opts[] = {
+	{ "list", required_argument, NULL, 'l' },
+	{ "help", no_argument, NULL, 'h' },
+	{ "version", no_argument, NULL, 'V' },
+};
+
+static const char *short_opts = "l:hV";
+
+static const char *help_string =
+"Usage: %s [OPTIONS] <squashfs-file>\n"
+"\n"
+"View or extract the contents of a squashfs image.\n"
+"\n"
+"Possible options:\n"
+"  --list, -l <path>  Produce a directory listing for a given path in the\n"
+"                     squashfs image.\n"
+"  --help, -h         Print help text and exit.\n"
+"  --version, -V      Print version information and exit.\n"
+"\n";
+
 extern const char *__progname;
 
+static tree_node_t *find_node(tree_node_t *n, const char *path)
+{
+	const char *end;
+	size_t len;
+
+	while (path != NULL && *path != '\0') {
+		if (!S_ISDIR(n->mode)) {
+			errno = ENOTDIR;
+			return NULL;
+		}
+
+		end = strchrnul(path, '/');
+		len = end - path;
+
+		for (n = n->data.dir->children; n != NULL; n = n->next) {
+			if (strncmp(path, n->name, len) != 0)
+				continue;
+			if (n->name[len] != '\0')
+				continue;
+			break;
+		}
+
+		if (n == NULL) {
+			errno = ENOENT;
+			return NULL;
+		}
+
+		path = *end ? (end + 1) : end;
+	}
+
+	return n;
+}
+
 int main(int argc, char **argv)
 {
-	int fd, status = EXIT_FAILURE;
+	int i, fd, status = EXIT_FAILURE;
+	char *lspath = NULL;
 	sqfs_super_t super;
 	compressor_t *cmp;
 	fstree_t fs;
 
-	if (argc != 2) {
-		fprintf(stderr, "Usage: %s <filename>\n", __progname);
-		return EXIT_FAILURE;
+	for (;;) {
+		i = getopt_long(argc, argv, short_opts, long_opts, NULL);
+		if (i == -1)
+			break;
+
+		switch (i) {
+		case 'l':
+			if (optarg != NULL) {
+				free(lspath);
+
+				lspath = strdup(optarg ? optarg : "");
+				if (lspath == NULL) {
+					perror("processing arguments");
+					return EXIT_FAILURE;
+				}
+
+				if (canonicalize_name(lspath)) {
+					fprintf(stderr, "Invalid pth: %s\n",
+						optarg);
+					goto out_cmd;
+				}
+			}
+			break;
+		case 'h':
+			printf(help_string, __progname);
+			status = EXIT_SUCCESS;
+			goto out_cmd;
+		case 'V':
+			print_version();
+			status = EXIT_SUCCESS;
+			goto out_cmd;
+		default:
+			goto fail_arg;
+		}
 	}
 
-	fd = open(argv[1], O_RDONLY);
+	if (optind >= argc) {
+		fprintf(stderr, "Usage: %s [OPTIONS] <filename>\n",
+			__progname);
+		goto out_cmd;
+	}
+
+	fd = open(argv[optind], O_RDONLY);
 	if (fd < 0) {
-		perror(argv[1]);
-		return EXIT_FAILURE;
+		perror(argv[optind]);
+		goto out_cmd;
 	}
 
 	if (sqfs_super_read(&super, fd))
-		goto out;
+		goto out_fd;
 
 	if ((super.version_major != SQFS_VERSION_MAJOR) ||
 	    (super.version_minor != SQFS_VERSION_MINOR)) {
@@ -31,34 +122,52 @@ int main(int argc, char **argv)
 			"We currently only supports version %d.%d (sorry).\n",
 			super.version_major, super.version_minor,
 			SQFS_VERSION_MAJOR, SQFS_VERSION_MINOR);
-		goto out;
+		goto out_fd;
 	}
 
 	if (super.flags & SQFS_FLAG_COMPRESSOR_OPTIONS) {
 		fputs("Image has been built with compressor options.\n"
 		      "This is not yet supported.\n",
 		      stderr);
-		goto out;
+		goto out_fd;
 	}
 
 	if (!compressor_exists(super.compression_id)) {
 		fputs("Image uses a compressor that has not been built in\n",
 		      stderr);
-		goto out;
+		goto out_fd;
 	}
 
 	cmp = compressor_create(super.compression_id, false, super.block_size);
 	if (cmp == NULL)
-		goto out;
+		goto out_fd;
 
 	if (read_fstree(&fs, fd, &super, cmp))
 		goto out_cmp;
 
+	if (lspath != NULL) {
+		tree_node_t *n = find_node(fs.root, lspath);
+
+		if (n == NULL) {
+			perror(lspath);
+			goto out_fs;
+		}
+
+		list_files(n);
+	}
+
 	status = EXIT_SUCCESS;
+out_fs:
 	fstree_cleanup(&fs);
 out_cmp:
 	cmp->destroy(cmp);
-out:
+out_fd:
 	close(fd);
+out_cmd:
+	free(lspath);
 	return status;
+fail_arg:
+	fprintf(stderr, "Try `%s --help' for more information.\n", __progname);
+	free(lspath);
+	return EXIT_FAILURE;
 }