tools: Add composefs-info tool

This lets you list the content of an image, and dump the objects
it references.

Signed-off-by: Alexander Larsson <[email protected]>

tools/Makefile.am

@@ -1,4 +1,6 @@
-bin_PROGRAMS = mkcomposefs
+COMPOSEFS_HASH_CFLAGS = -DUSE_OBSTACK=0 -DTESTING=0 -DUSE_DIFF_HASH=0
+
+bin_PROGRAMS = mkcomposefs composefs-info
 sbin_PROGRAMS = mount.composefs
 noinst_PROGRAMS =
 
@@ -21,6 +23,10 @@ mount_composefs_LDADD = ../libcomposefs/libcomposefs.la $(LIBCRYPTO_LIBS)
 composefs_from_json_SOURCES = composefs-from-json.c read-file.c read-file.h
 composefs_from_json_LDADD = ../libcomposefs/libcomposefs.la $(LIBS_YAJL) $(LIBCRYPTO_LIBS) $(LIBS_SECCOMP)
 
+composefs_info_SOURCES = composefs-info.c ../libcomposefs/hash.c
+composefs_info_CFLAGS = $(AM_CFLAGS) $(COMPOSEFS_HASH_CFLAGS)
+composefs_info_LDADD = ../libcomposefs/libcomposefs.la
+
 composefs_fuse_SOURCES = cfs-fuse.c
 composefs_fuse_LDADD =   ../libcomposefs/libcomposefs.la $(FUSE3_LIBS)
 composefs_fuse_CFLAGS =  $(AM_CFLAGS) $(FUSE3_CFLAGS)

tools/composefs-info.c

@@ -0,0 +1,294 @@
+/* lcfs
+   Copyright (C) 2023 Alexander Larsson <[email protected]>
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#define _GNU_SOURCE
+
+#include "config.h"
+
+#include "libcomposefs/lcfs-writer.h"
+#include "libcomposefs/lcfs-utils.h"
+#include "libcomposefs/lcfs-internal.h"
+#include "libcomposefs/hash.h"
+
+#include <stdio.h>
+#include <string.h>
+#include <err.h>
+#include <error.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <ctype.h>
+
+#define ESCAPE_STANDARD 0
+#define NOESCAPE_SPACE (1 << 0)
+#define ESCAPE_EQUAL (1 << 1)
+#define ESCAPE_LONE_DASH (1 << 2)
+
+static void print_escaped(const char *val, ssize_t len, int escape)
+{
+	bool noescape_space = (escape & NOESCAPE_SPACE) != 0;
+	bool escape_equal = (escape & ESCAPE_EQUAL) != 0;
+	bool escape_lone_dash = (escape & ESCAPE_LONE_DASH) != 0;
+
+	if (len < 0)
+		len = strlen(val);
+
+	if (escape_lone_dash && len == 1 && val[0] == '-') {
+		printf("\\x%.2x", val[0]);
+		return;
+	}
+
+	for (size_t i = 0; i < len; i++) {
+		uint8_t c = val[i];
+		bool hex_escape = false;
+		const char *special = NULL;
+		switch (c) {
+		case '\\':
+			special = "\\\\";
+			break;
+		case '\n':
+			special = "\\n";
+			break;
+		case '\r':
+			special = "\\r";
+			break;
+		case '\t':
+			special = "\\t";
+			break;
+		case '=':
+			hex_escape = escape_equal;
+			break;
+		default:
+			if (noescape_space)
+				hex_escape = !isprint(c);
+			else
+				hex_escape = !isgraph(c);
+			break;
+		}
+
+		if (special != NULL)
+			printf("%s", special);
+		else if (hex_escape)
+			printf("\\x%.2x", c);
+		else
+			printf("%c", c);
+	}
+}
+
+static void print_node(struct lcfs_node_s *node, char *parent_path)
+{
+	for (size_t i = 0; i < lcfs_node_get_n_children(node); i++) {
+		struct lcfs_node_s *child = lcfs_node_get_child(node, i);
+		cleanup_free char *path = NULL;
+
+		asprintf(&path, "%s/%s", parent_path, lcfs_node_get_name(child));
+
+		uint32_t mode = lcfs_node_get_mode(child);
+		uint32_t type = mode & S_IFMT;
+		const char *payload = lcfs_node_get_payload(child);
+
+		print_escaped(path, -1, NOESCAPE_SPACE);
+
+		if (type == S_IFDIR) {
+			printf("/\t");
+		} else if (type == S_IFLNK) {
+			printf("\t-> ");
+			print_escaped(payload, -1, ESCAPE_STANDARD);
+		} else if (type == S_IFREG && payload) {
+			printf("\t@ ");
+			print_escaped(payload, -1, ESCAPE_STANDARD);
+		}
+		printf("\n");
+
+		print_node(child, path);
+	}
+}
+
+static void digest_to_string(const uint8_t *csum, char *buf)
+{
+	static const char hexchars[] = "0123456789abcdef";
+	uint32_t i, j;
+
+	for (i = 0, j = 0; i < LCFS_DIGEST_SIZE; i++, j += 2) {
+		uint8_t byte = csum[i];
+		buf[j] = hexchars[byte >> 4];
+		buf[j + 1] = hexchars[byte & 0xF];
+	}
+	buf[j] = '\0';
+}
+
+static void dump_node(struct lcfs_node_s *node, char *path)
+{
+	struct lcfs_node_s *target;
+	struct timespec mtime;
+	const char *payload;
+	const uint8_t *digest;
+
+	target = lcfs_node_get_hardlink_target(node);
+	if (target == NULL)
+		target = node;
+
+	lcfs_node_get_mtime(target, &mtime);
+	payload = lcfs_node_get_payload(target);
+	digest = lcfs_node_get_fsverity_digest(target);
+
+	print_escaped(*path == 0 ? "/" : path, -1, ESCAPE_STANDARD);
+	printf(" %" PRIu64 " %s%o %u %u %u %u %" PRIi64 ".%u ",
+	       lcfs_node_get_size(target), target == node ? "" : "@",
+	       lcfs_node_get_mode(target), lcfs_node_get_nlink(target),
+	       lcfs_node_get_uid(target), lcfs_node_get_gid(target),
+	       lcfs_node_get_rdev(target), (int64_t)mtime.tv_sec,
+	       (unsigned int)mtime.tv_nsec);
+	print_escaped(payload ? payload : "-", -1, ESCAPE_LONE_DASH);
+
+	if (digest) {
+		char digest_str[LCFS_DIGEST_SIZE * 2 + 1] = { 0 };
+		digest_to_string(digest, digest_str);
+		printf(" %s", digest_str);
+	} else {
+		printf(" -");
+	}
+
+	size_t n_xattr = lcfs_node_get_n_xattr(target);
+	for (size_t i = 0; i < n_xattr; i++) {
+		const char *name = lcfs_node_get_xattr_name(target, i);
+		size_t value_len;
+		const char *value = lcfs_node_get_xattr(target, name, &value_len);
+
+		printf(" ");
+		print_escaped(name, -1, ESCAPE_EQUAL);
+		printf("=");
+		print_escaped(value, value_len, ESCAPE_EQUAL);
+	}
+
+	printf("\n");
+
+	for (size_t i = 0; i < lcfs_node_get_n_children(node); i++) {
+		struct lcfs_node_s *child = lcfs_node_get_child(node, i);
+		cleanup_free char *child_path = NULL;
+
+		asprintf(&child_path, "%s/%s", path, lcfs_node_get_name(child));
+
+		dump_node(child, child_path);
+	}
+}
+
+static void get_objects(struct lcfs_node_s *node, Hash_table *ht)
+{
+	uint32_t mode = lcfs_node_get_mode(node);
+	uint32_t type = mode & S_IFMT;
+	const char *payload = lcfs_node_get_payload(node);
+
+	if (type == S_IFREG && payload) {
+		if (hash_insert(ht, payload) == NULL) {
+			errx(EXIT_FAILURE, "Out of memory");
+		}
+	}
+
+	for (size_t i = 0; i < lcfs_node_get_n_children(node); i++) {
+		struct lcfs_node_s *child = lcfs_node_get_child(node, i);
+		get_objects(child, ht);
+	}
+}
+
+static size_t str_ht_hash(const void *entry, size_t table_size)
+{
+	return hash_string(entry, table_size);
+}
+
+static bool str_ht_eq(const void *entry1, const void *entry2)
+{
+	return strcmp(entry1, entry2) == 0;
+}
+
+static int cmp_obj(const void *_a, const void *_b)
+{
+	const char *const *a = _a;
+	const char *const *b = _b;
+	return strcmp(*a, *b);
+}
+
+static void print_objects(struct lcfs_node_s *node)
+{
+	Hash_table *ht = hash_initialize(0, NULL, str_ht_hash, str_ht_eq, NULL);
+	if (ht == NULL)
+		errx(EXIT_FAILURE, "Out of memory");
+
+	get_objects(node, ht);
+
+	size_t n_objects = hash_get_n_entries(ht);
+	char **objects = calloc(n_objects, sizeof(char *));
+
+	hash_get_entries(ht, (void **)objects, n_objects);
+
+	qsort(objects, n_objects, sizeof(char *), cmp_obj);
+
+	for (size_t i = 0; i < n_objects; i++)
+		printf("%s\n", objects[i]);
+
+	hash_free(ht);
+}
+
+static void usage(const char *argv0)
+{
+	fprintf(stderr, "usage: %s [ls|objects|dump] IMAGE\n", argv0);
+}
+
+int main(int argc, char **argv)
+{
+	const char *bin = argv[0];
+	int fd;
+	cleanup_node struct lcfs_node_s *root = NULL;
+	const char *image_path = NULL;
+	const char *command;
+
+	if (argc <= 1) {
+		fprintf(stderr, "No command specified\n");
+		usage(bin);
+		exit(1);
+	}
+	command = argv[1];
+
+	if (argc <= 2) {
+		fprintf(stderr, "No image path specified\n");
+		usage(bin);
+		exit(1);
+	}
+	image_path = argv[2];
+
+	fd = open(image_path, O_RDONLY | O_CLOEXEC);
+	if (fd < 0) {
+		err(EXIT_FAILURE, "Failed to open '%s'", image_path);
+	}
+
+	root = lcfs_load_node_from_fd(fd);
+	if (root == NULL) {
+		err(EXIT_FAILURE, "Failed to load '%s'", image_path);
+	}
+
+	if (strcmp(command, "ls") == 0) {
+		print_node(root, "");
+	} else if (strcmp(command, "dump") == 0) {
+		dump_node(root, "");
+	} else if (strcmp(command, "objects") == 0) {
+		print_objects(root);
+	} else {
+		errx(EXIT_FAILURE, "Unknown command '%s'\n", command);
+	}
+
+	return 0;
+}