libtar: Add an istream_t implementation

The tar_istream_t reads the data from a tar file, having been given
the header, and synthesizes zero bytes for sparse regions.

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

7 files changed, 570 insertions, 2 deletions

diff --git a/lib/tar/Makemodule.am b/lib/tar/Makemodule.am
index 896ce0f..9faeecf 100644
--- a/lib/tar/Makemodule.am
+++ b/lib/tar/Makemodule.am
@@ -3,7 +3,7 @@ libtar_a_SOURCES = lib/tar/src/read_header.c lib/tar/src/write_header.c \
 	lib/tar/src/read_sparse_map_old.c lib/tar/src/internal.h \
 	lib/tar/src/padd_file.c lib/tar/src/record_to_memory.c \
 	lib/tar/src/pax_header.c lib/tar/src/read_sparse_map_new.c \
-	include/tar/tar.h include/tar/format.h
+	lib/tar/src/istream.c include/tar/tar.h include/tar/format.h
 
 noinst_LIBRARIES += libtar.a
 
@@ -162,6 +162,20 @@ test_tar_xattr_schily_bin_LDADD = libtar.a libio.a libutil.a libcompat.a
 test_tar_xattr_schily_bin_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_xattr_schily_bin_CPPFLAGS += -DTESTFILE=xattr/xattr-schily-binary.tar
 
+test_tar_istream_SOURCES = lib/tar/test/tar_istream.c
+test_tar_istream_LDADD = libtar.a libio.a libutil.a libcompat.a
+test_tar_istream_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
+test_tar_istream_CPPFLAGS += -DTESTFILE=format-acceptance/gnu.tar
+
+test_tar_istream2_SOURCES = lib/tar/test/tar_istream2.c
+test_tar_istream2_LDADD = libtar.a libio.a libutil.a libcompat.a
+test_tar_istream2_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
+
+test_tar_istream3_SOURCES = lib/tar/test/tar_istream3.c
+test_tar_istream3_LDADD = libtar.a libio.a libutil.a libcompat.a
+test_tar_istream3_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
+test_tar_istream3_CPPFLAGS += -DTESTFILE=istream/sparse.tar
+
 tar_fuzz_SOURCES = lib/tar/test/tar_fuzz.c
 tar_fuzz_LDADD = libtar.a libio.a libutil.a libcompat.a
 
@@ -175,7 +189,8 @@ LIBTAR_TESTS = \
 	test_tar_sparse_gnu test_tar_sparse_gnu0 test_tar_sparse_gnu1 \
 	test_tar_sparse_gnu2 test_tar_sparse_gnu3 \
 	test_tar_xattr_bsd test_tar_xattr_schily test_tar_xattr_schily_bin \
-	test_tar_target_filled
+	test_tar_target_filled \
+	test_tar_istream test_tar_istream2 test_tar_istream3
 
 check_PROGRAMS += $(LIBTAR_TESTS)
 TESTS += $(LIBTAR_TESTS)
diff --git a/lib/tar/src/istream.c b/lib/tar/src/istream.c
new file mode 100644
index 0000000..30b8a34
--- /dev/null
+++ b/lib/tar/src/istream.c
@@ -0,0 +1,222 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * istream.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "internal.h"
+
+#include <string.h>
+#include <stdlib.h>
+
+typedef struct {
+	sqfs_u64 offset;
+	sqfs_u64 count;
+} sparse_ent_t;
+
+typedef struct {
+	istream_t base;
+
+	istream_t *parent;
+
+	char *filename;
+
+	sparse_ent_t *sparse;
+	size_t num_sparse;
+
+	sqfs_u64 record_size;
+	sqfs_u64 file_size;
+	sqfs_u64 offset;
+
+	size_t last_chunk;
+	bool last_sparse;
+
+	sqfs_u8 buffer[4096];
+} tar_istream_t;
+
+static bool is_sparse_region(tar_istream_t *tar, sqfs_u64 *count)
+{
+	size_t i;
+
+	*count = tar->file_size - tar->offset;
+	if (tar->num_sparse == 0)
+		return false;
+
+	for (i = 0; i < tar->num_sparse; ++i) {
+		if (tar->offset >= tar->sparse[i].offset) {
+			sqfs_u64 diff = tar->offset - tar->sparse[i].offset;
+
+			if (diff < tar->sparse[i].count) {
+				*count = tar->sparse[i].count - diff;
+				return false;
+			}
+		}
+	}
+
+	for (i = 0; i < tar->num_sparse; ++i) {
+		if (tar->offset < tar->sparse[i].offset) {
+			sqfs_u64 diff = tar->sparse[i].offset - tar->offset;
+
+			if (diff < *count)
+				*count = diff;
+		}
+	}
+
+	return true;
+}
+
+static int precache(istream_t *strm)
+{
+	tar_istream_t *tar = (tar_istream_t *)strm;
+	sqfs_u64 diff, avail;
+
+	tar->offset += tar->last_chunk;
+
+	if (!tar->last_sparse) {
+		tar->parent->buffer_offset += tar->last_chunk;
+		tar->record_size -= tar->last_chunk;
+	}
+
+	if (tar->offset >= tar->file_size) {
+		strm->eof = true;
+		strm->buffer_used = 0;
+		strm->buffer = tar->buffer;
+		if (tar->record_size > 0)
+			goto fail_rec_sz;
+		return 0;
+	}
+
+	if (is_sparse_region(tar, &diff)) {
+		if (diff > sizeof(tar->buffer))
+			diff = sizeof(tar->buffer);
+
+		strm->buffer = tar->buffer;
+		strm->buffer_used = diff;
+		tar->last_chunk = diff;
+		tar->last_sparse = true;
+
+		memset(tar->buffer, 0, diff);
+	} else {
+		if (diff > tar->record_size)
+			goto fail_rec_sz;
+
+		avail = tar->parent->buffer_used - tar->parent->buffer_offset;
+
+		if ((diff > avail) &&
+		    ((tar->parent->buffer_offset > 0) || avail == 0)) {
+			if (istream_precache(tar->parent))
+				return -1;
+
+			if (tar->parent->buffer_used == 0 && tar->parent->eof)
+				goto fail_eof;
+
+			avail = tar->parent->buffer_used;
+		}
+
+		if (diff > avail)
+			diff = avail;
+
+		strm->buffer = tar->parent->buffer + tar->parent->buffer_offset;
+		strm->buffer_used = diff;
+		tar->last_chunk = diff;
+		tar->last_sparse = false;
+	}
+
+	return 0;
+fail_rec_sz:
+	fprintf(stderr,
+		"%s: missmatch in tar record size vs file size for `%s`.\n",
+		istream_get_filename(tar->parent), istream_get_filename(strm));
+	return -1;
+fail_eof:
+	fprintf(stderr, "%s: unexpected end-of-file while reading `%s`\n",
+		istream_get_filename(tar->parent), istream_get_filename(strm));
+	return -1;
+}
+
+static const char *get_filename(istream_t *strm)
+{
+	return ((tar_istream_t *)strm)->filename;
+}
+
+static void tar_istream_destroy(sqfs_object_t *obj)
+{
+	tar_istream_t *strm = (tar_istream_t *)obj;
+
+	sqfs_drop(strm->parent);
+	free(strm->sparse);
+	free(strm->filename);
+	free(strm);
+}
+
+istream_t *tar_record_istream_create(istream_t *parent,
+				     const tar_header_decoded_t *hdr)
+{
+	tar_istream_t *strm;
+	sparse_map_t *it;
+	sqfs_u64 diff;
+	size_t idx;
+
+	strm = calloc(1, sizeof(*strm));
+	if (strm == NULL)
+		goto fail_oom;
+
+	sqfs_object_init(strm, tar_istream_destroy, NULL);
+
+	strm->filename = strdup(hdr->name);
+	if (strm->filename == NULL)
+		goto fail_oom;
+
+	strm->num_sparse = 0;
+	for (it = hdr->sparse; it != NULL; it = it->next)
+		strm->num_sparse += 1;
+
+	if (strm->num_sparse > 0) {
+		strm->sparse = alloc_array(sizeof(strm->sparse[0]),
+					   strm->num_sparse);
+		if (strm->sparse == NULL)
+			goto fail_oom;
+
+		idx = 0;
+		it = hdr->sparse;
+		while (it != NULL && idx < strm->num_sparse) {
+			strm->sparse[idx].offset = it->offset;
+			strm->sparse[idx].count = it->count;
+			++idx;
+			it = it->next;
+		}
+	}
+
+	for (idx = 1; idx < strm->num_sparse; ++idx) {
+		if (strm->sparse[idx].offset <= strm->sparse[idx - 1].offset)
+			goto fail_sparse;
+
+		diff = strm->sparse[idx].offset - strm->sparse[idx - 1].offset;
+
+		if (diff < strm->sparse[idx - 1].count)
+			goto fail_sparse;
+	}
+
+	strm->record_size = hdr->record_size;
+	strm->file_size = hdr->actual_size;
+	strm->parent = sqfs_grab(parent);
+
+	((istream_t *)strm)->precache = precache;
+	((istream_t *)strm)->get_filename = get_filename;
+	((istream_t *)strm)->buffer = strm->buffer;
+	((istream_t *)strm)->eof = false;
+	return (istream_t *)strm;
+fail_sparse:
+	fprintf(stderr, "%s: sparse map is not ordered or overlapping!\n",
+		hdr->name);
+	goto fail;
+fail_oom:
+	fputs("tar istream create: out-of-memory\n", stderr);
+	goto fail;
+fail:
+	if (strm != NULL) {
+		free(strm->filename);
+		free(strm);
+	}
+	return NULL;
+}
diff --git a/lib/tar/test/data/CREDITS b/lib/tar/test/data/CREDITS
index 7a2738f..dab8951 100644
--- a/lib/tar/test/data/CREDITS
+++ b/lib/tar/test/data/CREDITS
@@ -33,3 +33,6 @@ The following addtional files have been added:
      Contributed in GitHub issue #64. A tar ball that contains a hard link
      where the 100 byte target field is completely filled without containing
      a null-terminator.
+ - istream/sparse.tar
+     Derived from sparse/gnu.tar and contains some test data for testing the
+     tar istream implementation.
diff --git a/lib/tar/test/data/istream/sparse.tar b/lib/tar/test/data/istream/sparse.tar
new file mode 100644
index 0000000..7f4700d
--- /dev/null
+++ b/lib/tar/test/data/istream/sparse.tar
diff --git a/lib/tar/test/tar_istream.c b/lib/tar/test/tar_istream.c
new file mode 100644
index 0000000..cc31282
--- /dev/null
+++ b/lib/tar/test/tar_istream.c
@@ -0,0 +1,73 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * tar_istream.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "config.h"
+#include "io/file.h"
+#include "tar/tar.h"
+#include "util/test.h"
+
+#ifndef TESTUID
+#define TESTUID 1000
+#endif
+
+#ifndef TESTGID
+#define TESTGID TESTUID
+#endif
+
+#ifndef TESTFNAME
+#define TESTFNAME input.txt
+#endif
+
+#ifndef TESTTS
+#define TESTTS 1542905892
+#endif
+
+static const char *fname = STRVALUE(TESTFNAME);
+
+int main(int argc, char **argv)
+{
+	tar_header_decoded_t hdr;
+	char buffer[100];
+	sqfs_s64 ts;
+	istream_t *fp;
+	istream_t *ti;
+	sqfs_s32 ret;
+	(void)argc; (void)argv;
+
+	fp = istream_open_file(STRVALUE(TESTPATH) "/" STRVALUE(TESTFILE));
+	TEST_NOT_NULL(fp);
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
+	TEST_ASSERT(read_header(fp, &hdr) == 0);
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
+	TEST_EQUAL_UI(hdr.mode, S_IFREG | 0644);
+	TEST_EQUAL_UI(hdr.uid, TESTUID);
+	TEST_EQUAL_UI(hdr.gid, TESTGID);
+	TEST_EQUAL_UI(hdr.actual_size, 5);
+
+	ts = TESTTS;
+	TEST_EQUAL_UI(hdr.mtime, ts);
+	TEST_STR_EQUAL(hdr.name, fname);
+	TEST_ASSERT(!hdr.unknown_record);
+
+	ti = tar_record_istream_create(fp, &hdr);
+	TEST_NOT_NULL(ti);
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 2);
+	TEST_EQUAL_UI(((sqfs_object_t *)ti)->refcount, 1);
+
+	ret = istream_read(ti, buffer, sizeof(buffer));
+	TEST_EQUAL_I(ret, 5);
+	buffer[5] = '\0';
+	TEST_STR_EQUAL(buffer, "test\n");
+
+	ret = istream_read(ti, buffer, sizeof(buffer));
+	TEST_EQUAL_I(ret, 0);
+
+	clear_header(&hdr);
+	sqfs_drop(ti);
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
+	sqfs_drop(fp);
+	return EXIT_SUCCESS;
+}
diff --git a/lib/tar/test/tar_istream2.c b/lib/tar/test/tar_istream2.c
new file mode 100644
index 0000000..a3f27d5
--- /dev/null
+++ b/lib/tar/test/tar_istream2.c
@@ -0,0 +1,155 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * tar_istream2.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "config.h"
+#include "io/file.h"
+#include "tar/tar.h"
+#include "util/test.h"
+
+int main(int argc, char **argv)
+{
+	tar_header_decoded_t hdr;
+	char buffer[100];
+	istream_t *fp;
+	istream_t *ti;
+	(void)argc; (void)argv;
+
+	TEST_ASSERT(chdir(TEST_PATH) == 0);
+
+	fp = istream_open_file("format-acceptance/link_filled.tar");
+	TEST_NOT_NULL(fp);
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
+
+	/* "deep" directory hierarchy containg 2 files */
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
+	TEST_ASSERT(read_header(fp, &hdr) == 0);
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
+	TEST_EQUAL_UI(hdr.mode, S_IFDIR | 0777);
+	TEST_STR_EQUAL(hdr.name, "20_characters_here01/");
+	clear_header(&hdr);
+
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
+	TEST_ASSERT(read_header(fp, &hdr) == 0);
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
+	TEST_EQUAL_UI(hdr.mode, S_IFDIR | 0777);
+	TEST_STR_EQUAL(hdr.name, "20_characters_here01/20_characters_here02/");
+	clear_header(&hdr);
+
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
+	TEST_ASSERT(read_header(fp, &hdr) == 0);
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
+	TEST_EQUAL_UI(hdr.mode, S_IFDIR | 0777);
+	TEST_STR_EQUAL(hdr.name, "20_characters_here01/20_characters_here02/"
+		       "20_characters_here03/");
+	clear_header(&hdr);
+
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
+	TEST_ASSERT(read_header(fp, &hdr) == 0);
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
+	TEST_EQUAL_UI(hdr.mode, S_IFDIR | 0777);
+	TEST_STR_EQUAL(hdr.name, "20_characters_here01/20_characters_here02/"
+		       "20_characters_here03/20_characters_here04/");
+	clear_header(&hdr);
+
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
+	TEST_ASSERT(read_header(fp, &hdr) == 0);
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
+	TEST_EQUAL_UI(hdr.mode, S_IFREG | 0777);
+	TEST_STR_EQUAL(hdr.name, "20_characters_here01/20_characters_here02/"
+		       "20_characters_here03/20_characters_here04/"
+		       "errored_file_tst");
+	TEST_EQUAL_UI(hdr.actual_size, 5);
+
+	ti = tar_record_istream_create(fp, &hdr);
+	TEST_NOT_NULL(ti);
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 2);
+	TEST_EQUAL_UI(((sqfs_object_t *)ti)->refcount, 1);
+	clear_header(&hdr);
+
+	TEST_ASSERT(istream_read(ti, buffer, sizeof(buffer)) == 5);
+	buffer[5] = '\0';
+	TEST_STR_EQUAL(buffer, "test\n");
+	TEST_ASSERT(istream_read(ti, buffer, sizeof(buffer)) == 0);
+
+	ti = sqfs_drop(ti);
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
+
+	TEST_ASSERT(skip_padding(fp, 5) == 0);
+
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
+	TEST_ASSERT(read_header(fp, &hdr) == 0);
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
+	TEST_EQUAL_UI(hdr.mode, S_IFREG | 0777);
+	TEST_STR_EQUAL(hdr.name, "20_characters_here01/20_characters_here02/"
+		       "20_characters_here03/20_characters_here04/"
+		       "some_test_file");
+	TEST_EQUAL_UI(hdr.actual_size, 5);
+
+	ti = tar_record_istream_create(fp, &hdr);
+	TEST_NOT_NULL(ti);
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 2);
+	TEST_EQUAL_UI(((sqfs_object_t *)ti)->refcount, 1);
+	clear_header(&hdr);
+
+	TEST_ASSERT(istream_read(ti, buffer, sizeof(buffer)) == 5);
+	buffer[5] = '\0';
+	TEST_STR_EQUAL(buffer, "test\n");
+	TEST_ASSERT(istream_read(ti, buffer, sizeof(buffer)) == 0);
+
+	ti = sqfs_drop(ti);
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
+
+	TEST_ASSERT(skip_padding(fp, 5) == 0);
+
+	/* "deep" directory hierarchy containg a hard link */
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
+	TEST_ASSERT(read_header(fp, &hdr) == 0);
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
+	TEST_EQUAL_UI(hdr.mode, S_IFDIR | 0777);
+	TEST_STR_EQUAL(hdr.name, "20CharsForLnkTest001/");
+	clear_header(&hdr);
+
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
+	TEST_ASSERT(read_header(fp, &hdr) == 0);
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
+	TEST_EQUAL_UI(hdr.mode, S_IFDIR | 0777);
+	TEST_STR_EQUAL(hdr.name, "20CharsForLnkTest001/20CharsForLnkTest002/");
+	clear_header(&hdr);
+
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
+	TEST_ASSERT(read_header(fp, &hdr) == 0);
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
+	TEST_EQUAL_UI(hdr.mode, S_IFDIR | 0777);
+	TEST_STR_EQUAL(hdr.name, "20CharsForLnkTest001/20CharsForLnkTest002/"
+		       "20CharsForLnkTest003/");
+	clear_header(&hdr);
+
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
+	TEST_ASSERT(read_header(fp, &hdr) == 0);
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
+	TEST_EQUAL_UI(hdr.mode, S_IFDIR | 0777);
+	TEST_STR_EQUAL(hdr.name, "20CharsForLnkTest001/20CharsForLnkTest002/"
+		       "20CharsForLnkTest003/20CharsForLnkTest004/");
+	clear_header(&hdr);
+
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
+	TEST_ASSERT(read_header(fp, &hdr) == 0);
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
+	TEST_STR_EQUAL(hdr.name, "20CharsForLnkTest001/20CharsForLnkTest002/"
+		       "20CharsForLnkTest003/20CharsForLnkTest004/"
+		       "01234567890123456789");
+	TEST_ASSERT(hdr.is_hard_link);
+
+	TEST_STR_EQUAL(hdr.link_target, "20_characters_here01/"
+		       "20_characters_here02/20_characters_here03/"
+		       "20_characters_here04/errored_file_tst");
+	clear_header(&hdr);
+
+	/* end of file */
+	TEST_ASSERT(read_header(fp, &hdr) > 0);
+	sqfs_drop(fp);
+	return EXIT_SUCCESS;
+}
diff --git a/lib/tar/test/tar_istream3.c b/lib/tar/test/tar_istream3.c
new file mode 100644
index 0000000..d287081
--- /dev/null
+++ b/lib/tar/test/tar_istream3.c
@@ -0,0 +1,100 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * tar_istream3.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "config.h"
+#include "io/file.h"
+#include "tar/tar.h"
+#include "util/test.h"
+
+static const struct {
+	uint64_t offset;
+	size_t size;
+	int fill;
+} regions[] = {
+	{       0, 4096, 'A' },
+	{  262144, 4096, 'B' },
+	{  524288, 4096, 'C' },
+	{  786432, 4096, 'D' },
+	{ 1048576, 4096, 'E' },
+	{ 1310720, 4096, 'F' },
+	{ 1572864, 4096, 'G' },
+	{ 1835008, 4096, 'H' },
+};
+
+static int byte_from_offset(uint64_t offset)
+{
+	sqfs_u64 diff;
+	size_t i;
+
+	for (i = 0; i < sizeof(regions) / sizeof(regions[0]); ++i) {
+		if (offset >= regions[i].offset) {
+			diff = (offset - regions[i].offset);
+
+			if (diff < regions[i].size)
+				return regions[i].fill;
+		}
+	}
+
+	return '\0';
+}
+
+int main(int argc, char **argv)
+{
+	unsigned char buffer[941];
+	tar_header_decoded_t hdr;
+	istream_t *fp, *ti;
+	uint64_t offset;
+	sqfs_s32 i, ret;
+	(void)argc; (void)argv;
+
+	fp = istream_open_file(STRVALUE(TESTPATH) "/" STRVALUE(TESTFILE));
+	TEST_NOT_NULL(fp);
+	TEST_ASSERT(read_header(fp, &hdr) == 0);
+	TEST_EQUAL_UI(hdr.mode, S_IFREG | 0644);
+	TEST_EQUAL_UI(hdr.uid, 01750);
+	TEST_EQUAL_UI(hdr.gid, 01750);
+	TEST_EQUAL_UI(hdr.actual_size, 2097152);
+	TEST_EQUAL_UI(hdr.record_size, 32768);
+	TEST_STR_EQUAL(hdr.name, "input.bin");
+	TEST_ASSERT(!hdr.unknown_record);
+
+	ti = tar_record_istream_create(fp, &hdr);
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 2);
+	TEST_EQUAL_UI(((sqfs_object_t *)ti)->refcount, 1);
+	clear_header(&hdr);
+
+	offset = 0;
+
+	for (;;) {
+		ret = istream_read(ti, buffer, sizeof(buffer));
+		TEST_ASSERT(ret >= 0);
+
+		if (ret == 0)
+			break;
+
+		for (i = 0; i < ret; ++i) {
+			int ref_byte = byte_from_offset(offset + i);
+
+			if (buffer[i] != ref_byte) {
+				fprintf(stderr, "Byte at offset %llu should "
+					"be 0x%02X, but is 0x%02X\n",
+					(unsigned long long)(offset + i),
+					(unsigned int)ref_byte, buffer[i]);
+				return EXIT_FAILURE;
+			}
+		}
+
+		offset += ret;
+		TEST_ASSERT(offset <= 2097152);
+	}
+
+	TEST_EQUAL_UI(offset, 2097152);
+
+	sqfs_drop(ti);
+	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
+	sqfs_drop(fp);
+	return EXIT_SUCCESS;
+}