Merge functionality of file on disk and file in sqfs compare functions

Moving towards unified sqfs vs sqfs, sqfs vs dir, dir vs sqfs
comparisions.

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

7 files changed, 104 insertions, 135 deletions

diff --git a/difftool/Makemodule.am b/difftool/Makemodule.am
index 8d0a4e7..293143e 100644
--- a/difftool/Makemodule.am
+++ b/difftool/Makemodule.am
@@ -1,6 +1,6 @@
 sqfsdiff_SOURCES = difftool/sqfsdiff.c difftool/difftool.h difftool/util.c
 sqfsdiff_SOURCES += difftool/compare_dir.c difftool/node_compare.c
-sqfsdiff_SOURCES += difftool/compare_files_sqfs.c difftool/super.c
+sqfsdiff_SOURCES += difftool/compare_files.c difftool/super.c
 sqfsdiff_SOURCES += difftool/extract.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_file.c b/difftool/compare_file.c
deleted file mode 100644
index c427f38..0000000
--- a/difftool/compare_file.c
+++ /dev/null
@@ -1,78 +0,0 @@
-/* SPDX-License-Identifier: GPL-3.0-or-later */
-/*
- * compare_file.c
- *
- * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
- */
-#include "difftool.h"
-
-int compare_files(file_info_t *a, file_info_t *b, const char *path)
-{
-	uint64_t offset, size, diff;
-	int ret = 0, afd, bfd;
-	void *aptr, *bptr;
-
-	if (a->size != b->size)
-		return 1;
-
-	if (pushd(first_path))
-		return -1;
-	afd = open(path, O_RDONLY);
-	if (afd < 0) {
-		fprintf(stderr, "%s/%s: %s\n", first_path, path,
-			strerror(errno));
-		return -1;
-	}
-	if (popd())
-		goto fail_afd;
-
-	if (pushd(second_path))
-		goto fail_afd;
-	bfd = open(path, O_RDONLY);
-	if (bfd < 0) {
-		fprintf(stderr, "%s/%s: %s\n", second_path, path,
-			strerror(errno));
-		goto fail_afd;
-	}
-	if (popd())
-		goto fail_bfd;
-
-	size = a->size;
-
-	for (offset = 0; offset < size; offset += diff) {
-		diff = size - offset;
-		if (diff > MAX_WINDOW_SIZE)
-			diff = MAX_WINDOW_SIZE;
-
-		aptr = mmap(NULL, diff, PROT_READ, MAP_SHARED, afd, offset);
-		if (aptr == MAP_FAILED) {
-			fprintf(stderr, "mmap %s/%s: %s\n", first_path, path,
-				strerror(errno));
-			goto fail_bfd;
-		}
-
-		bptr = mmap(NULL, diff, PROT_READ, MAP_SHARED, bfd, offset);
-		if (bptr == MAP_FAILED) {
-			fprintf(stderr, "mmap %s/%s: %s\n", second_path, path,
-				strerror(errno));
-			munmap(aptr, diff);
-			goto fail_bfd;
-		}
-
-		ret = memcmp(aptr, bptr, diff);
-		munmap(aptr, diff);
-		munmap(bptr, diff);
-
-		if (ret != 0)
-			break;
-	}
-
-	close(afd);
-	close(bfd);
-	return ret;
-fail_bfd:
-	close(bfd);
-fail_afd:
-	close(afd);
-	return -1;
-}
diff --git a/difftool/compare_files.c b/difftool/compare_files.c
new file mode 100644
index 0000000..89c5f5c
--- /dev/null
+++ b/difftool/compare_files.c
@@ -0,0 +1,97 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * compare_files.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "difftool.h"
+
+static unsigned char a_buf[MAX_WINDOW_SIZE];
+static unsigned char b_buf[MAX_WINDOW_SIZE];
+
+int compare_files(file_info_t *a, file_info_t *b, const char *path)
+{
+	char second_name[strlen(second_path) + strlen(path) + 2];
+	char first_name[strlen(first_path) + strlen(path) + 2];
+	int afd = -1, bfd = -1, status = 0;
+	uint64_t offset, diff;
+	ssize_t ret;
+
+	if (a->size != b->size)
+		goto out_different;
+
+	if (compare_flags & COMPARE_NO_CONTENTS)
+		return 0;
+
+	if (a_is_dir) {
+		sprintf(first_name, "%s/%s", first_path, path);
+
+		afd = open(first_name, O_RDONLY);
+		if (afd < 0) {
+			perror(first_name);
+			goto fail;
+		}
+	}
+
+	if (b_is_dir) {
+		sprintf(second_name, "%s/%s", second_path, path);
+
+		bfd = open(second_name, O_RDONLY);
+		if (bfd < 0) {
+			perror(second_name);
+			goto fail;
+		}
+	}
+
+	for (offset = 0; offset < a->size; offset += diff) {
+		diff = a->size - offset;
+
+		if (diff > MAX_WINDOW_SIZE)
+			diff = MAX_WINDOW_SIZE;
+
+		if (a_is_dir) {
+			if (read_data_at(first_name, offset, afd, a_buf, diff))
+				goto out;
+		} else {
+			ret = data_reader_read(sqfs_a.data, a, offset,
+					       a_buf, diff);
+			if (ret < 0 || (size_t)ret < diff) {
+				fprintf(stderr, "Failed to read %s from %s\n",
+					path, first_path);
+				return -1;
+			}
+		}
+
+		if (b_is_dir) {
+			if (read_data_at(second_name, offset, bfd, b_buf, diff))
+				goto out;
+		} else {
+			ret = data_reader_read(sqfs_b.data, b, offset,
+					       b_buf, diff);
+			if (ret < 0 || (size_t)ret < diff) {
+				fprintf(stderr, "Failed to read %s from %s\n",
+					path, second_path);
+				return -1;
+			}
+		}
+
+		if (memcmp(a_buf, b_buf, diff) != 0)
+			goto out_different;
+	}
+out:
+	if (afd >= 0)
+		close(afd);
+	if (bfd >= 0)
+		close(bfd);
+	return status;
+fail:
+	status = -1;
+	goto out;
+out_different:
+	if (compare_flags & COMPARE_EXTRACT_FILES) {
+		if (extract_files(a, b, path))
+			goto fail;
+	}
+	status = 1;
+	goto out;
+}
diff --git a/difftool/compare_files_sqfs.c b/difftool/compare_files_sqfs.c
deleted file mode 100644
index 32b97b1..0000000
--- a/difftool/compare_files_sqfs.c
+++ /dev/null
@@ -1,54 +0,0 @@
-/* SPDX-License-Identifier: GPL-3.0-or-later */
-/*
- * compare_file_sfqs.c
- *
- * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
- */
-#include "difftool.h"
-
-static unsigned char a_buf[MAX_WINDOW_SIZE];
-static unsigned char b_buf[MAX_WINDOW_SIZE];
-
-int compare_files(file_info_t *a, file_info_t *b, const char *path)
-{
-	uint64_t offset, diff;
-	ssize_t ret;
-
-	if (a->size != b->size)
-		goto out_different;
-
-	if (compare_flags & COMPARE_NO_CONTENTS)
-		return 0;
-
-	for (offset = 0; offset < a->size; offset += diff) {
-		diff = a->size - offset;
-
-		if (diff > MAX_WINDOW_SIZE)
-			diff = MAX_WINDOW_SIZE;
-
-		ret = data_reader_read(sqfs_a.data, a, offset, a_buf, diff);
-		if (ret < 0 || (size_t)ret < diff) {
-			fprintf(stderr, "Failed to read %s from %s\n",
-				path, first_path);
-			return -1;
-		}
-
-		ret = data_reader_read(sqfs_b.data, b, offset, b_buf, diff);
-		if (ret < 0 || (size_t)ret < diff) {
-			fprintf(stderr, "Failed to read %s from %s\n",
-				path, second_path);
-			return -1;
-		}
-
-		if (memcmp(a_buf, b_buf, diff) != 0)
-			goto out_different;
-	}
-
-	return 0;
-out_different:
-	if (compare_flags & COMPARE_EXTRACT_FILES) {
-		if (extract_files(a, b, path))
-			return -1;
-	}
-	return 1;
-}
diff --git a/difftool/difftool.h b/difftool/difftool.h
index bd04fd2..56f727a 100644
--- a/difftool/difftool.h
+++ b/difftool/difftool.h
@@ -28,6 +28,8 @@ extern const char *second_path;
 extern int compare_flags;
 extern sqfs_reader_t sqfs_a;
 extern sqfs_reader_t sqfs_b;
+extern bool a_is_dir;
+extern bool b_is_dir;
 
 enum {
 	COMPARE_NO_PERM = 0x01,
diff --git a/difftool/extract.c b/difftool/extract.c
index 9d84265..9fee46d 100644
--- a/difftool/extract.c
+++ b/difftool/extract.c
@@ -39,12 +39,12 @@ static int extract(data_reader_t *data, file_info_t *fi,
 
 int extract_files(file_info_t *a, file_info_t *b, const char *path)
 {
-	if (a != NULL) {
+	if (a != NULL && !a_is_dir) {
 		if (extract(sqfs_a.data, a, path, 'a'))
 			return -1;
 	}
 
-	if (b != NULL) {
+	if (b != NULL && !b_is_dir) {
 		if (extract(sqfs_b.data, b, path, 'b'))
 			return -1;
 	}
diff --git a/difftool/sqfsdiff.c b/difftool/sqfsdiff.c
index baebc25..9197430 100644
--- a/difftool/sqfsdiff.c
+++ b/difftool/sqfsdiff.c
@@ -65,6 +65,8 @@ const char *first_path;
 const char *second_path;
 sqfs_reader_t sqfs_a;
 sqfs_reader_t sqfs_b;
+bool a_is_dir;
+bool b_is_dir;
 static bool compare_super = false;
 static const char *extract_dir;