Move tar compressor auto wrapping code from tar2sqfs into libtar

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

5 files changed, 88 insertions, 82 deletions

diff --git a/bin/tar2sqfs/src/process_tarball.c b/bin/tar2sqfs/src/process_tarball.c
index 9ad7d9a..91572ec 100644
--- a/bin/tar2sqfs/src/process_tarball.c
+++ b/bin/tar2sqfs/src/process_tarball.c
@@ -148,16 +148,10 @@ static int set_root_attribs(sqfs_writer_t *sqfs, dir_iterator_t *it,
 	return 0;
 }
 
-int process_tarball(istream_t *input_file, sqfs_writer_t *sqfs)
+int process_tarball(dir_iterator_t *it, sqfs_writer_t *sqfs)
 {
-	dir_iterator_t *it = tar_open_stream(input_file);
 	size_t rootlen = root_becomes == NULL ? 0 : strlen(root_becomes);
 
-	if (it == NULL) {
-		fputs("Creating tar stream: out-of-memory\n", stderr);
-		return -1;
-	}
-
 	for (;;) {
 		bool skip = false, is_root = false, is_prefixed = true;
 		dir_entry_t *ent = NULL;
@@ -168,7 +162,7 @@ int process_tarball(istream_t *input_file, sqfs_writer_t *sqfs)
 		if (ret > 0)
 			break;
 		if (ret < 0)
-			goto fail;
+			return -1;
 
 		if (ent->mtime < 0)
 			ent->mtime = 0;
@@ -181,7 +175,7 @@ int process_tarball(istream_t *input_file, sqfs_writer_t *sqfs)
 			if (ret != 0) {
 				sqfs_perror(ent->name, "read link", ret);
 				free(ent);
-				goto fail;
+				return -1;
 			}
 		}
 
@@ -235,12 +229,8 @@ int process_tarball(istream_t *input_file, sqfs_writer_t *sqfs)
 		free(ent);
 		free(link);
 		if (ret)
-			goto fail;
+			return -1;
 	}
 
-	sqfs_drop(it);
 	return 0;
-fail:
-	sqfs_drop(it);
-	return -1;
 }
diff --git a/bin/tar2sqfs/src/tar2sqfs.c b/bin/tar2sqfs/src/tar2sqfs.c
index 1145675..b09f920 100644
--- a/bin/tar2sqfs/src/tar2sqfs.c
+++ b/bin/tar2sqfs/src/tar2sqfs.c
@@ -6,65 +6,11 @@
  */
 #include "tar2sqfs.h"
 
-static int tar_probe(const sqfs_u8 *data, size_t size)
-{
-	size_t i, offset;
-
-	if (size >= TAR_RECORD_SIZE) {
-		for (i = 0; i < TAR_RECORD_SIZE; ++i) {
-			if (data[i] != 0x00)
-				break;
-		}
-
-		if (i == TAR_RECORD_SIZE) {
-			data += TAR_RECORD_SIZE;
-			size -= TAR_RECORD_SIZE;
-		}
-	}
-
-	offset = offsetof(tar_header_t, magic);
-
-	if (offset + 5 <= size) {
-		if (memcmp(data + offset, "ustar", 5) == 0)
-			return 1;
-	}
-
-	return 0;
-}
-
-static istream_t *magic_autowrap(istream_t *strm)
-{
-	xfrm_stream_t *xfrm = NULL;
-	istream_t *wrapper = NULL;
-	int ret;
-
-	ret = istream_precache(strm);
-	if (ret != 0)
-		goto out;
-
-	ret = tar_probe(strm->buffer, strm->buffer_used);
-	if (ret > 0)
-		return strm;
-
-	ret = xfrm_compressor_id_from_magic(strm->buffer, strm->buffer_used);
-	if (ret <= 0)
-		return strm;
-
-	xfrm = decompressor_stream_create(ret);
-	if (xfrm == NULL)
-		goto out;
-
-	wrapper = istream_xfrm_create(strm, xfrm);
-out:
-	sqfs_drop(strm);
-	sqfs_drop(xfrm);
-	return wrapper;
-}
-
 int main(int argc, char **argv)
 {
 	int status = EXIT_FAILURE;
 	istream_t *input_file = NULL;
+	dir_iterator_t *tar = NULL;
 	sqfs_writer_t sqfs;
 
 	process_args(argc, argv);
@@ -73,15 +19,18 @@ int main(int argc, char **argv)
 	if (input_file == NULL)
 		return EXIT_FAILURE;
 
-	input_file = magic_autowrap(input_file);
-	if (input_file == NULL)
+	tar = tar_open_stream(input_file);
+	sqfs_drop(input_file);
+	if (tar == NULL) {
+		fputs("Creating tar stream: out-of-memory\n", stderr);
 		return EXIT_FAILURE;
+	}
 
 	memset(&sqfs, 0, sizeof(sqfs));
 	if (sqfs_writer_init(&sqfs, &cfg))
-		goto out_if;
+		goto out_it;
 
-	if (process_tarball(input_file, &sqfs))
+	if (process_tarball(tar, &sqfs))
 		goto out;
 
 	if (fstree_post_process(&sqfs.fs))
@@ -93,7 +42,7 @@ int main(int argc, char **argv)
 	status = EXIT_SUCCESS;
 out:
 	sqfs_writer_cleanup(&sqfs, status);
-out_if:
-	sqfs_drop(input_file);
+out_it:
+	sqfs_drop(tar);
 	return status;
 }
diff --git a/bin/tar2sqfs/src/tar2sqfs.h b/bin/tar2sqfs/src/tar2sqfs.h
index a21774b..e853ae9 100644
--- a/bin/tar2sqfs/src/tar2sqfs.h
+++ b/bin/tar2sqfs/src/tar2sqfs.h
@@ -15,7 +15,6 @@
 #include "tar/tar.h"
 #include "tar/format.h"
 #include "xfrm/compress.h"
-#include "io/xfrm.h"
 
 #include <stdlib.h>
 #include <getopt.h>
@@ -34,6 +33,6 @@ extern char *root_becomes;
 void process_args(int argc, char **argv);
 
 /* process_tarball.c */
-int process_tarball(istream_t *input_file, sqfs_writer_t *sqfs);
+int process_tarball(dir_iterator_t *it, sqfs_writer_t *sqfs);
 
 #endif /* TAR2SQFS_H */
diff --git a/lib/tar/Makemodule.am b/lib/tar/Makemodule.am
index 9061571..4dc5057 100644
--- a/lib/tar/Makemodule.am
+++ b/lib/tar/Makemodule.am
@@ -173,17 +173,23 @@ test_tar_xattr_schily_bin_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_xattr_schily_bin_CPPFLAGS += -DTESTFILE=xattr/xattr-schily-binary.tar
 
 test_tar_iterator_SOURCES = lib/tar/test/tar_iterator.c
-test_tar_iterator_LDADD = libtar.a libsquashfs.la libio.a libutil.a libcompat.a
+test_tar_iterator_LDADD = libtar.a libsquashfs.la libxfrm.a libio.a \
+		libutil.a libcompat.a $(XZ_LIBS) $(BZIP2_LIBS) \
+		$(ZLIB_LIBS) $(ZSTD_LIBS)
 test_tar_iterator_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_iterator_CPPFLAGS += -DTESTFILE=format-acceptance/gnu.tar
 
 test_tar_iterator2_SOURCES = lib/tar/test/tar_iterator2.c
-test_tar_iterator2_LDADD = libtar.a libsquashfs.la libio.a libutil.a libcompat.a
+test_tar_iterator2_LDADD = libtar.a libsquashfs.la libio.a libxfrm.a \
+		libutil.a libcompat.a $(XZ_LIBS) $(BZIP2_LIBS) \
+		$(ZLIB_LIBS) $(ZSTD_LIBS)
 test_tar_iterator2_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_iterator2_CPPFLAGS += -DTESTFILE=iterator/sparse.tar
 
 test_tar_iterator3_SOURCES = lib/tar/test/tar_iterator3.c
-test_tar_iterator3_LDADD = libtar.a libsquashfs.la libio.a libutil.a libcompat.a
+test_tar_iterator3_LDADD = libtar.a libsquashfs.la libio.a libxfrm.a \
+		libutil.a libcompat.a $(XZ_LIBS) $(BZIP2_LIBS) \
+		$(ZLIB_LIBS) $(ZSTD_LIBS)
 test_tar_iterator3_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 
 tar_fuzz_SOURCES = lib/tar/test/tar_fuzz.c
diff --git a/lib/tar/src/iterator.c b/lib/tar/src/iterator.c
index 216c528..85937c8 100644
--- a/lib/tar/src/iterator.c
+++ b/lib/tar/src/iterator.c
@@ -4,10 +4,13 @@
  *
  * Copyright (C) 2023 David Oberhollenzer <goliath@infraroot.at>
  */
+#include "xfrm/compress.h"
+#include "tar/format.h"
 #include "tar/tar.h"
 #include "sqfs/error.h"
 #include "sqfs/xattr.h"
 #include "util/util.h"
+#include "io/xfrm.h"
 
 #include <stdlib.h>
 #include <string.h>
@@ -311,16 +314,45 @@ static void it_destroy(sqfs_object_t *obj)
 	free(tar);
 }
 
-dir_iterator_t *tar_open_stream(istream_t *stream)
+/*****************************************************************************/
+
+static int tar_probe(const sqfs_u8 *data, size_t size)
+{
+	size_t i, offset;
+
+	if (size >= TAR_RECORD_SIZE) {
+		for (i = 0; i < TAR_RECORD_SIZE; ++i) {
+			if (data[i] != 0x00)
+				break;
+		}
+
+		if (i == TAR_RECORD_SIZE) {
+			data += TAR_RECORD_SIZE;
+			size -= TAR_RECORD_SIZE;
+		}
+	}
+
+	offset = offsetof(tar_header_t, magic);
+
+	if (offset + 5 <= size) {
+		if (memcmp(data + offset, "ustar", 5) == 0)
+			return 1;
+	}
+
+	return 0;
+}
+
+dir_iterator_t *tar_open_stream(istream_t *strm)
 {
 	tar_iterator_t *tar = calloc(1, sizeof(*tar));
 	dir_iterator_t *it = (dir_iterator_t *)tar;
+	xfrm_stream_t *xfrm = NULL;
+	int ret;
 
 	if (tar == NULL)
 		return NULL;
 
 	sqfs_object_init(it, it_destroy, NULL);
-	tar->stream = sqfs_grab(stream);
 	it->next = it_next;
 	it->read_link = it_read_link;
 	it->open_subdir = it_open_subdir;
@@ -328,5 +360,35 @@ dir_iterator_t *tar_open_stream(istream_t *stream)
 	it->open_file_ro = it_open_file_ro;
 	it->read_xattr = it_read_xattr;
 
+	/* proble if the stream is compressed */
+	ret = istream_precache(strm);
+	if (ret != 0)
+		goto out_strm;
+
+	ret = tar_probe(strm->buffer, strm->buffer_used);
+	if (ret > 0)
+		goto out_strm;
+
+	ret = xfrm_compressor_id_from_magic(strm->buffer, strm->buffer_used);
+	if (ret <= 0)
+		goto out_strm;
+
+	/* auto-wrap a compressed source stream */
+	xfrm = decompressor_stream_create(ret);
+	if (xfrm == NULL) {
+		sqfs_drop(it);
+		return NULL;
+	}
+
+	tar->stream = istream_xfrm_create(strm, xfrm);
+	if (tar->stream == NULL) {
+		sqfs_drop(xfrm);
+		sqfs_drop(it);
+		return NULL;
+	}
+
+	return it;
+out_strm:
+	tar->stream = sqfs_grab(strm);
 	return it;
 }