Isolate sqfsdiff global state and split off option processing

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

7 files changed, 195 insertions, 185 deletions

diff --git a/difftool/Makemodule.am b/difftool/Makemodule.am
index e687cb0..9b6e713 100644
--- a/difftool/Makemodule.am
+++ b/difftool/Makemodule.am
@@ -1,7 +1,7 @@
 sqfsdiff_SOURCES = difftool/sqfsdiff.c difftool/sqfsdiff.h difftool/util.c
 sqfsdiff_SOURCES += difftool/compare_dir.c difftool/node_compare.c
 sqfsdiff_SOURCES += difftool/compare_files.c difftool/super.c
-sqfsdiff_SOURCES += difftool/extract.c
+sqfsdiff_SOURCES += difftool/extract.c difftool/options.c
 sqfsdiff_LDADD = libsquashfs.a libfstree.a libcompress.a libutil.a
 sqfsdiff_LDADD += $(XZ_LIBS) $(ZLIB_LIBS) $(LZO_LIBS) $(LZ4_LIBS) $(ZSTD_LIBS)
 
diff --git a/difftool/compare_files.c b/difftool/compare_files.c
index 46e170b..605df84 100644
--- a/difftool/compare_files.c
+++ b/difftool/compare_files.c
@@ -9,10 +9,11 @@
 static unsigned char old_buf[MAX_WINDOW_SIZE];
 static unsigned char new_buf[MAX_WINDOW_SIZE];
 
-int compare_files(file_info_t *old, file_info_t *new, const char *path)
+int compare_files(sqfsdiff_t *sd, file_info_t *old, file_info_t *new,
+		  const char *path)
 {
-	char new_name[strlen(new_path) + strlen(path) + 2];
-	char old_name[strlen(old_path) + strlen(path) + 2];
+	char new_name[strlen(sd->new_path) + strlen(path) + 2];
+	char old_name[strlen(sd->old_path) + strlen(path) + 2];
 	int old_fd = -1, new_fd = -1, status = 0;
 	uint64_t offset, diff;
 	ssize_t ret;
@@ -20,11 +21,11 @@ int compare_files(file_info_t *old, file_info_t *new, const char *path)
 	if (old->size != new->size)
 		goto out_different;
 
-	if (compare_flags & COMPARE_NO_CONTENTS)
+	if (sd->compare_flags & COMPARE_NO_CONTENTS)
 		return 0;
 
-	if (old_is_dir) {
-		sprintf(old_name, "%s/%s", old_path, path);
+	if (sd->old_is_dir) {
+		sprintf(old_name, "%s/%s", sd->old_path, path);
 
 		old_fd = open(old_name, O_RDONLY);
 		if (old_fd < 0) {
@@ -33,8 +34,8 @@ int compare_files(file_info_t *old, file_info_t *new, const char *path)
 		}
 	}
 
-	if (new_is_dir) {
-		sprintf(new_name, "%s/%s", new_path, path);
+	if (sd->new_is_dir) {
+		sprintf(new_name, "%s/%s", sd->new_path, path);
 
 		new_fd = open(new_name, O_RDONLY);
 		if (new_fd < 0) {
@@ -49,30 +50,30 @@ int compare_files(file_info_t *old, file_info_t *new, const char *path)
 		if (diff > MAX_WINDOW_SIZE)
 			diff = MAX_WINDOW_SIZE;
 
-		if (old_is_dir) {
+		if (sd->old_is_dir) {
 			if (read_data_at(old_name, offset, old_fd,
 					 old_buf, diff))
 				goto out;
 		} else {
-			ret = data_reader_read(sqfs_old.data, old, offset,
+			ret = data_reader_read(sd->sqfs_old.data, old, offset,
 					       old_buf, diff);
 			if (ret < 0 || (size_t)ret < diff) {
 				fprintf(stderr, "Failed to read %s from %s\n",
-					path, old_path);
+					path, sd->old_path);
 				return -1;
 			}
 		}
 
-		if (new_is_dir) {
+		if (sd->new_is_dir) {
 			if (read_data_at(new_name, offset, new_fd,
 					 new_buf, diff))
 				goto out;
 		} else {
-			ret = data_reader_read(sqfs_new.data, new, offset,
+			ret = data_reader_read(sd->sqfs_new.data, new, offset,
 					       new_buf, diff);
 			if (ret < 0 || (size_t)ret < diff) {
 				fprintf(stderr, "Failed to read %s from %s\n",
-					path, new_path);
+					path, sd->new_path);
 				return -1;
 			}
 		}
@@ -90,8 +91,8 @@ fail:
 	status = -1;
 	goto out;
 out_different:
-	if (compare_flags & COMPARE_EXTRACT_FILES) {
-		if (extract_files(old, new, path))
+	if (sd->compare_flags & COMPARE_EXTRACT_FILES) {
+		if (extract_files(sd, old, new, path))
 			goto fail;
 	}
 	status = 1;
diff --git a/difftool/extract.c b/difftool/extract.c
index f40de60..cefba62 100644
--- a/difftool/extract.c
+++ b/difftool/extract.c
@@ -37,15 +37,16 @@ static int extract(data_reader_t *data, file_info_t *fi,
 	return 0;
 }
 
-int extract_files(file_info_t *old, file_info_t *new, const char *path)
+int extract_files(sqfsdiff_t *sd, file_info_t *old, file_info_t *new,
+		  const char *path)
 {
-	if (old != NULL && !old_is_dir) {
-		if (extract(sqfs_old.data, old, path, 'a'))
+	if (old != NULL && !sd->old_is_dir) {
+		if (extract(sd->sqfs_old.data, old, path, 'a'))
 			return -1;
 	}
 
-	if (new != NULL && !new_is_dir) {
-		if (extract(sqfs_new.data, new, path, 'b'))
+	if (new != NULL && !sd->new_is_dir) {
+		if (extract(sd->sqfs_new.data, new, path, 'b'))
 			return -1;
 	}
 	return 0;
diff --git a/difftool/node_compare.c b/difftool/node_compare.c
index 1c68ab2..35fd07b 100644
--- a/difftool/node_compare.c
+++ b/difftool/node_compare.c
@@ -6,7 +6,7 @@
  */
 #include "sqfsdiff.h"
 
-int node_compare(tree_node_t *a, tree_node_t *b)
+int node_compare(sqfsdiff_t *sd, tree_node_t *a, tree_node_t *b)
 {
 	char *path = node_path(a);
 	tree_node_t *ait, *bit;
@@ -21,7 +21,7 @@ int node_compare(tree_node_t *a, tree_node_t *b)
 		return 1;
 	}
 
-	if (!(compare_flags & COMPARE_NO_PERM)) {
+	if (!(sd->compare_flags & COMPARE_NO_PERM)) {
 		if ((a->mode & ~S_IFMT) != (b->mode & ~S_IFMT)) {
 			fprintf(stdout, "%s has different permissions\n",
 				path);
@@ -29,21 +29,21 @@ int node_compare(tree_node_t *a, tree_node_t *b)
 		}
 	}
 
-	if (!(compare_flags & COMPARE_NO_OWNER)) {
+	if (!(sd->compare_flags & COMPARE_NO_OWNER)) {
 		if (a->uid != b->uid || a->gid != b->gid) {
 			fprintf(stdout, "%s has different ownership\n", path);
 			status = 1;
 		}
 	}
 
-	if (compare_flags & COMPARE_TIMESTAMP) {
+	if (sd->compare_flags & COMPARE_TIMESTAMP) {
 		if (a->mod_time != b->mod_time) {
 			fprintf(stdout, "%s has a different timestamp\n", path);
 			status = 1;
 		}
 	}
 
-	if (compare_flags & COMPARE_INODE_NUM) {
+	if (sd->compare_flags & COMPARE_INODE_NUM) {
 		if (a->inode_num != b->inode_num) {
 			fprintf(stdout, "%s has a different inode number\n",
 				path);
@@ -85,7 +85,7 @@ int node_compare(tree_node_t *a, tree_node_t *b)
 		bit = b->data.dir->children;
 
 		while (ait != NULL && bit != NULL) {
-			ret = node_compare(ait, bit);
+			ret = node_compare(sd, ait, bit);
 			if (ret < 0)
 				return -1;
 			if (ret > 0)
@@ -96,7 +96,7 @@ int node_compare(tree_node_t *a, tree_node_t *b)
 		}
 		break;
 	case S_IFREG:
-		ret = compare_files(a->data.file, b->data.file, path);
+		ret = compare_files(sd, a->data.file, b->data.file, path);
 		if (ret < 0) {
 			status = -1;
 		} else if (ret > 0) {
diff --git a/difftool/options.c b/difftool/options.c
new file mode 100644
index 0000000..8224b1d
--- /dev/null
+++ b/difftool/options.c
@@ -0,0 +1,130 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * sqfsdiff.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "sqfsdiff.h"
+
+static struct option long_opts[] = {
+	{ "old", required_argument, NULL, 'a' },
+	{ "new", required_argument, NULL, 'b' },
+	{ "no-owner", no_argument, NULL, 'O' },
+	{ "no-permissions", no_argument, NULL, 'P' },
+	{ "no-contents", no_argument, NULL, 'C' },
+	{ "timestamps", no_argument, NULL, 'T' },
+	{ "inode-num", no_argument, NULL, 'I' },
+	{ "super", no_argument, NULL, 'S' },
+	{ "extract", required_argument, NULL, 'e' },
+	{ "help", no_argument, NULL, 'h' },
+	{ "version", no_argument, NULL, 'V' },
+};
+
+static const char *short_opts = "a:b:OPCTISe:hV";
+
+static const char *usagestr =
+"Usage: sqfsdiff [OPTIONS...] --old,-a <first> --new,-b <second>\n"
+"\n"
+"Compare two squashfs images. In contrast to doing a direct diff of the\n"
+"images, this actually parses the filesystems and generates a more\n"
+"meaningful difference report.\n"
+"\n"
+"If only contents are compared, any differences in packed file layout,\n"
+"ordering, compression, inode allocation and so on is ignored and the two\n"
+"images are considered equal if each directory contains the same entries,\n"
+"symlink with the same paths have the same targets, device nodes the same\n"
+"device number and files the same size and contents.\n"
+"\n"
+"A report of any difference is printed to stdout. The exit status is similar\n"
+"that of diff(1): 0 means equal, 1 means different, 2 means problem.\n"
+"\n"
+"Possible options:\n"
+"\n"
+"  --old, -a <first>           The first of the two images to compare.\n"
+"  --new, -b <second>          The second of the two images to compare.\n"
+"\n"
+"  --no-contents, -C           Do not compare file contents.\n"
+"  --no-owner, -O              Do not compare file owners.\n"
+"  --no-permissions, -P        Do not compare permission bits.\n"
+"\n"
+"  --timestamps, -T            Compare file timestamps.\n"
+"  --inode-num, -I             Compare inode numbers of all files.\n"
+"  --super, -S                 Also compare metadata in super blocks.\n"
+"\n"
+"  --extract, -e <path>        Extract files that differ to the specified\n"
+"                              directory. Contents of the first image end up\n"
+"                              in a subdirectory 'a' and of the second image\n"
+"                              in a subdirectory 'b'.\n"
+"\n"
+"  --help, -h                  Print help text and exit.\n"
+"  --version, -V               Print version information and exit.\n"
+"\n";
+
+void process_options(sqfsdiff_t *sd, int argc, char **argv)
+{
+	int i;
+
+	for (;;) {
+		i = getopt_long(argc, argv, short_opts, long_opts, NULL);
+		if (i == -1)
+			break;
+
+		switch (i) {
+		case 'a':
+			sd->old_path = optarg;
+			break;
+		case 'b':
+			sd->new_path = optarg;
+			break;
+		case 'O':
+			sd->compare_flags |= COMPARE_NO_OWNER;
+			break;
+		case 'P':
+			sd->compare_flags |= COMPARE_NO_PERM;
+			break;
+		case 'C':
+			sd->compare_flags |= COMPARE_NO_CONTENTS;
+			break;
+		case 'T':
+			sd->compare_flags |= COMPARE_TIMESTAMP;
+			break;
+		case 'I':
+			sd->compare_flags |= COMPARE_INODE_NUM;
+			break;
+		case 'S':
+			sd->compare_super = true;
+			break;
+		case 'e':
+			sd->compare_flags |= COMPARE_EXTRACT_FILES;
+			sd->extract_dir = optarg;
+			break;
+		case 'h':
+			fputs(usagestr, stdout);
+			exit(EXIT_SUCCESS);
+		case 'V':
+			print_version();
+			exit(EXIT_SUCCESS);
+		default:
+			goto fail_arg;
+		}
+	}
+
+	if (sd->old_path == NULL) {
+		fputs("Missing arguments: first filesystem\n", stderr);
+		goto fail_arg;
+	}
+
+	if (sd->new_path == NULL) {
+		fputs("Missing arguments: second filesystem\n", stderr);
+		goto fail_arg;
+	}
+
+	if (optind < argc) {
+		fputs("Unknown extra arguments\n", stderr);
+		goto fail_arg;
+	}
+	return;
+fail_arg:
+	fprintf(stderr, "Try `sqfsdiff --help' for more information.\n");
+	exit(EXIT_FAILURE);
+}
diff --git a/difftool/sqfsdiff.c b/difftool/sqfsdiff.c
index ddc2686..2bc733b 100644
--- a/difftool/sqfsdiff.c
+++ b/difftool/sqfsdiff.c
@@ -6,172 +6,42 @@
  */
 #include "sqfsdiff.h"
 
-static struct option long_opts[] = {
-	{ "old", required_argument, NULL, 'a' },
-	{ "new", required_argument, NULL, 'b' },
-	{ "no-owner", no_argument, NULL, 'O' },
-	{ "no-permissions", no_argument, NULL, 'P' },
-	{ "no-contents", no_argument, NULL, 'C' },
-	{ "timestamps", no_argument, NULL, 'T' },
-	{ "inode-num", no_argument, NULL, 'I' },
-	{ "super", no_argument, NULL, 'S' },
-	{ "extract", required_argument, NULL, 'e' },
-	{ "help", no_argument, NULL, 'h' },
-	{ "version", no_argument, NULL, 'V' },
-};
-
-static const char *short_opts = "a:b:OPCTISe:hV";
-
-static const char *usagestr =
-"Usage: sqfsdiff [OPTIONS...] --old,-a <first> --new,-b <second>\n"
-"\n"
-"Compare two squashfs images. In contrast to doing a direct diff of the\n"
-"images, this actually parses the filesystems and generates a more\n"
-"meaningful difference report.\n"
-"\n"
-"If only contents are compared, any differences in packed file layout,\n"
-"ordering, compression, inode allocation and so on is ignored and the two\n"
-"images are considered equal if each directory contains the same entries,\n"
-"symlink with the same paths have the same targets, device nodes the same\n"
-"device number and files the same size and contents.\n"
-"\n"
-"A report of any difference is printed to stdout. The exit status is similar\n"
-"that of diff(1): 0 means equal, 1 means different, 2 means problem.\n"
-"\n"
-"Possible options:\n"
-"\n"
-"  --old, -a <first>           The first of the two images to compare.\n"
-"  --new, -b <second>          The second of the two images to compare.\n"
-"\n"
-"  --no-contents, -C           Do not compare file contents.\n"
-"  --no-owner, -O              Do not compare file owners.\n"
-"  --no-permissions, -P        Do not compare permission bits.\n"
-"\n"
-"  --timestamps, -T            Compare file timestamps.\n"
-"  --inode-num, -I             Compare inode numbers of all files.\n"
-"  --super, -S                 Also compare metadata in super blocks.\n"
-"\n"
-"  --extract, -e <path>        Extract files that differ to the specified\n"
-"                              directory. Contents of the first image end up\n"
-"                              in a subdirectory 'a' and of the second image\n"
-"                              in a subdirectory 'b'.\n"
-"\n"
-"  --help, -h                  Print help text and exit.\n"
-"  --version, -V               Print version information and exit.\n"
-"\n";
-
-int compare_flags = 0;
-const char *old_path;
-const char *new_path;
-sqfs_reader_t sqfs_old;
-sqfs_reader_t sqfs_new;
-bool old_is_dir;
-bool new_is_dir;
-static bool compare_super = false;
-static const char *extract_dir;
-
-static void process_options(int argc, char **argv)
-{
-	int i;
-
-	for (;;) {
-		i = getopt_long(argc, argv, short_opts, long_opts, NULL);
-		if (i == -1)
-			break;
-
-		switch (i) {
-		case 'a':
-			old_path = optarg;
-			break;
-		case 'b':
-			new_path = optarg;
-			break;
-		case 'O':
-			compare_flags |= COMPARE_NO_OWNER;
-			break;
-		case 'P':
-			compare_flags |= COMPARE_NO_PERM;
-			break;
-		case 'C':
-			compare_flags |= COMPARE_NO_CONTENTS;
-			break;
-		case 'T':
-			compare_flags |= COMPARE_TIMESTAMP;
-			break;
-		case 'I':
-			compare_flags |= COMPARE_INODE_NUM;
-			break;
-		case 'S':
-			compare_super = true;
-			break;
-		case 'e':
-			compare_flags |= COMPARE_EXTRACT_FILES;
-			extract_dir = optarg;
-			break;
-		case 'h':
-			fputs(usagestr, stdout);
-			exit(EXIT_SUCCESS);
-		case 'V':
-			print_version();
-			exit(EXIT_SUCCESS);
-		default:
-			goto fail_arg;
-		}
-	}
-
-	if (old_path == NULL) {
-		fputs("Missing arguments: first filesystem\n", stderr);
-		goto fail_arg;
-	}
-
-	if (new_path == NULL) {
-		fputs("Missing arguments: second filesystem\n", stderr);
-		goto fail_arg;
-	}
-
-	if (optind < argc) {
-		fputs("Unknown extra arguments\n", stderr);
-		goto fail_arg;
-	}
-	return;
-fail_arg:
-	fprintf(stderr, "Try `sqfsdiff --help' for more information.\n");
-	exit(EXIT_FAILURE);
-}
-
 int main(int argc, char **argv)
 {
 	int status, ret = 0;
+	sqfsdiff_t sd;
 
-	process_options(argc, argv);
+	memset(&sd, 0, sizeof(sd));
+	process_options(&sd, argc, argv);
 
-	if (extract_dir != NULL) {
-		if (mkdir_p(extract_dir))
+	if (sd.extract_dir != NULL) {
+		if (mkdir_p(sd.extract_dir))
 			return EXIT_FAILURE;
 	}
 
-	if (sqfs_reader_open(&sqfs_old, old_path, 0))
+	if (sqfs_reader_open(&sd.sqfs_old, sd.old_path, 0))
 		return 2;
 
-	if (sqfs_reader_open(&sqfs_new, new_path, 0)) {
+	if (sqfs_reader_open(&sd.sqfs_new, sd.new_path, 0)) {
 		status = 2;
 		goto out_sqfs_old;
 	}
 
-	if (extract_dir != NULL) {
-		if (chdir(extract_dir)) {
-			perror(extract_dir);
+	if (sd.extract_dir != NULL) {
+		if (chdir(sd.extract_dir)) {
+			perror(sd.extract_dir);
 			ret = -1;
 			goto out;
 		}
 	}
 
-	ret = node_compare(sqfs_old.fs.root, sqfs_new.fs.root);
+	ret = node_compare(&sd, sd.sqfs_old.fs.root, sd.sqfs_new.fs.root);
 	if (ret != 0)
 		goto out;
 
-	if (compare_super) {
-		ret = compare_super_blocks(&sqfs_old.super, &sqfs_new.super);
+	if (sd.compare_super) {
+		ret = compare_super_blocks(&sd.sqfs_old.super,
+					   &sd.sqfs_new.super);
 		if (ret != 0)
 			goto out;
 	}
@@ -183,8 +53,8 @@ out:
 	} else {
 		status = 0;
 	}
-	sqfs_reader_close(&sqfs_new);
+	sqfs_reader_close(&sd.sqfs_new);
 out_sqfs_old:
-	sqfs_reader_close(&sqfs_old);
+	sqfs_reader_close(&sd.sqfs_old);
 	return status;
 }
diff --git a/difftool/sqfsdiff.h b/difftool/sqfsdiff.h
index f7d5139..ce6929f 100644
--- a/difftool/sqfsdiff.h
+++ b/difftool/sqfsdiff.h
@@ -23,13 +23,17 @@
 
 #define MAX_WINDOW_SIZE (1024 * 1024 * 4)
 
-extern const char *old_path;
-extern const char *new_path;
-extern int compare_flags;
-extern sqfs_reader_t sqfs_old;
-extern sqfs_reader_t sqfs_new;
-extern bool old_is_dir;
-extern bool new_is_dir;
+typedef struct {
+	const char *old_path;
+	const char *new_path;
+	int compare_flags;
+	sqfs_reader_t sqfs_old;
+	sqfs_reader_t sqfs_new;
+	bool old_is_dir;
+	bool new_is_dir;
+	bool compare_super;
+	const char *extract_dir;
+} sqfsdiff_t;
 
 enum {
 	COMPARE_NO_PERM = 0x01,
@@ -44,12 +48,16 @@ int compare_dir_entries(tree_node_t *a, tree_node_t *b);
 
 char *node_path(tree_node_t *n);
 
-int compare_files(file_info_t *a, file_info_t *b, const char *path);
+int compare_files(sqfsdiff_t *sd, file_info_t *a, file_info_t *b,
+		  const char *path);
 
-int node_compare(tree_node_t *a, tree_node_t *b);
+int node_compare(sqfsdiff_t *sd, tree_node_t *a, tree_node_t *b);
 
 int compare_super_blocks(const sqfs_super_t *a, const sqfs_super_t *b);
 
-int extract_files(file_info_t *a, file_info_t *b, const char *path);
+int extract_files(sqfsdiff_t *sd, file_info_t *old, file_info_t *new,
+		  const char *path);
+
+void process_options(sqfsdiff_t *sd, int argc, char **argv);
 
 #endif /* DIFFTOOL_H */