Add support for reading old style GNU sparse tar file format

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

2 files changed, 133 insertions, 2 deletions

diff --git a/tests/Makemodule.am b/tests/Makemodule.am
index e9cb8c4..004f83c 100644
--- a/tests/Makemodule.am
+++ b/tests/Makemodule.am
@@ -46,16 +46,20 @@ test_tar_ustar_SOURCES = tests/tar_ustar.c
 test_tar_ustar_LDADD = libtar.a libutil.a
 test_tar_ustar_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(top_srcdir)/tests/tar
 
+test_tar_sparse_gnu_SOURCES = tests/tar_sparse_gnu.c
+test_tar_sparse_gnu_LDADD = libtar.a libutil.a
+test_tar_sparse_gnu_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(top_srcdir)/tests/tar
+
 check_PROGRAMS += test_canonicalize_name test_mknode_simple test_mknode_slink
 check_PROGRAMS += test_mknode_reg test_mknode_dir test_gen_inode_table
 check_PROGRAMS += test_add_by_path test_get_path test_fstree_sort
 check_PROGRAMS += test_fstree_from_file test_fstree_init test_fstree_xattr
-check_PROGRAMS += test_tar_ustar test_tar_pax test_tar_gnu
+check_PROGRAMS += test_tar_ustar test_tar_pax test_tar_gnu test_tar_sparse_gnu
 
 TESTS += test_canonicalize_name test_mknode_simple test_mknode_slink
 TESTS += test_mknode_reg test_mknode_dir test_gen_inode_table
 TESTS += test_add_by_path test_get_path test_fstree_sort test_fstree_from_file
 TESTS += test_fstree_init test_fstree_xattr test_tar_ustar test_tar_pax
-TESTS += test_tar_gnu
+TESTS += test_tar_gnu test_tar_sparse_gnu
 
 EXTRA_DIST += $(top_srcdir)/tests/tar
diff --git a/tests/tar_sparse_gnu.c b/tests/tar_sparse_gnu.c
new file mode 100644
index 0000000..2f2e1c5
--- /dev/null
+++ b/tests/tar_sparse_gnu.c
@@ -0,0 +1,127 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+#include "util.h"
+#include "tar.h"
+
+#include <unistd.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <stdio.h>
+
+#define STR(x) #x
+#define STRVALUE(x) STR(x)
+
+#define TEST_PATH STRVALUE(TESTPATH)
+
+static int open_read(const char *path)
+{
+	int fd = open(path, O_RDONLY);
+
+	if (fd < 0) {
+		perror(path);
+		exit(EXIT_FAILURE);
+	}
+
+	return fd;
+}
+
+int main(void)
+{
+	tar_sparse_data_t *sparse;
+	tar_header_decoded_t hdr;
+	int fd;
+
+	assert(chdir(TEST_PATH) == 0);
+
+	fd = open_read("sparse-files/gnu-small.tar");
+	assert(read_header(fd, &hdr) == 0);
+	assert(hdr.sb.st_mode == (S_IFREG | 0644));
+	assert(hdr.sb.st_uid == 01750);
+	assert(hdr.sb.st_gid == 01750);
+	assert(hdr.sb.st_size == 524288);
+	assert(strcmp(hdr.name, "input.bin") == 0);
+	assert(!hdr.unknown_record);
+
+	sparse = hdr.sparse;
+	assert(sparse != NULL);
+	assert(sparse->offset == 0);
+	assert(sparse->count == 4096);
+
+	sparse = sparse->next;
+	assert(sparse != NULL);
+	assert(sparse->offset == 262144);
+	assert(sparse->count == 4096);
+
+	sparse = sparse->next;
+	assert(sparse != NULL);
+	assert(sparse->offset == 524288);
+	assert(sparse->count == 0);
+
+	assert(sparse->next == NULL);
+
+	clear_header(&hdr);
+	close(fd);
+
+	fd = open_read("sparse-files/gnu.tar");
+	assert(read_header(fd, &hdr) == 0);
+	assert(hdr.sb.st_mode == (S_IFREG | 0644));
+	assert(hdr.sb.st_uid == 01750);
+	assert(hdr.sb.st_gid == 01750);
+	assert(hdr.sb.st_size == 2097152);
+	assert(strcmp(hdr.name, "input.bin") == 0);
+	assert(!hdr.unknown_record);
+
+	sparse = hdr.sparse;
+	assert(sparse != NULL);
+	assert(sparse->offset == 0);
+	assert(sparse->count == 4096);
+
+	sparse = sparse->next;
+	assert(sparse != NULL);
+	assert(sparse->offset == 262144);
+	assert(sparse->count == 4096);
+
+	sparse = sparse->next;
+	assert(sparse != NULL);
+	assert(sparse->offset == 524288);
+	assert(sparse->count == 4096);
+
+	sparse = sparse->next;
+	assert(sparse != NULL);
+	assert(sparse->offset == 786432);
+	assert(sparse->count == 4096);
+
+	sparse = sparse->next;
+	assert(sparse != NULL);
+	assert(sparse->offset == 1048576);
+	assert(sparse->count == 4096);
+
+	sparse = sparse->next;
+	assert(sparse != NULL);
+	assert(sparse->offset == 1310720);
+	assert(sparse->count == 4096);
+
+	sparse = sparse->next;
+	assert(sparse != NULL);
+	assert(sparse->offset == 1572864);
+	assert(sparse->count == 4096);
+
+	sparse = sparse->next;
+	assert(sparse != NULL);
+	assert(sparse->offset == 1835008);
+	assert(sparse->count == 4096);
+
+	sparse = sparse->next;
+	assert(sparse != NULL);
+	assert(sparse->offset == 2097152);
+	assert(sparse->count == 0);
+
+	sparse = sparse->next;
+	assert(sparse == NULL);
+
+	clear_header(&hdr);
+	close(fd);
+
+	return EXIT_SUCCESS;
+}