Overhaul sqfs_istream_t/sqfs_ostream_t error handling

Report an error number from the implementations, change the users to
forward that error number (which also means libtar write header/link
now returns an error code) and all subsequent binaries to use
sqfs_perror() instead of relying on the function to print an error
internally.

Also, make sure to preserve errno/GetLastError() in the implementations
and print out a stringified error in sqfs_perror() if the error code
indicates an I/O error.

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

42 files changed, 490 insertions, 359 deletions

diff --git a/bin/gensquashfs/Makemodule.am b/bin/gensquashfs/Makemodule.am
index 98153cb..dd32d5a 100644
--- a/bin/gensquashfs/Makemodule.am
+++ b/bin/gensquashfs/Makemodule.am
@@ -26,7 +26,7 @@ test_filemap_xattr_SOURCES = bin/gensquashfs/test/filemap_xattr.c \
 test_filemap_xattr_CPPFLAGS = $(AM_CPPFLAGS) -I$(top_srcdir)/bin/gensquashfs/src
 test_filemap_xattr_CPPFLAGS += -DTESTPATH=$(GENDATADIR)/xattr1.txt
 test_filemap_xattr_LDADD = libio.a libsquashfs.la libfstree.a libutil.a
-test_filemap_xattr_LDADD += libcompat.a
+test_filemap_xattr_LDADD += libcommon.a libcompat.a
 
 test_fstree_from_file_SOURCES = bin/gensquashfs/test/fstree_from_file.c \
 				bin/gensquashfs/src/fstree_from_file.c \
diff --git a/bin/gensquashfs/src/filemap_xattr.c b/bin/gensquashfs/src/filemap_xattr.c
index 89624f4..8843c46 100644
--- a/bin/gensquashfs/src/filemap_xattr.c
+++ b/bin/gensquashfs/src/filemap_xattr.c
@@ -159,8 +159,12 @@ xattr_open_map_file(const char *path) {
 	struct XattrMap *map;
 	size_t line_num = 1;
 	char *p = NULL;
-	sqfs_istream_t *file = istream_open_file(path);
-	if (file == NULL) {
+	sqfs_istream_t *file = NULL;
+	int ret;
+
+	ret = istream_open_file(&file, path);
+	if (ret) {
+		sqfs_perror(path, NULL, ret);
 		return NULL;
 	}
 
diff --git a/bin/gensquashfs/src/fstree_from_file.c b/bin/gensquashfs/src/fstree_from_file.c
index efb5d43..f392b34 100644
--- a/bin/gensquashfs/src/fstree_from_file.c
+++ b/bin/gensquashfs/src/fstree_from_file.c
@@ -313,9 +313,11 @@ int fstree_from_file(fstree_t *fs, const char *filename, const char *basepath)
 	sqfs_istream_t *fp;
 	int ret;
 
-	fp = istream_open_file(filename);
-	if (fp == NULL)
+	ret = istream_open_file(&fp, filename);
+	if (ret) {
+		sqfs_perror(filename, NULL, ret);
 		return -1;
+	}
 
 	ret = fstree_from_file_stream(fs, fp, basepath);
 
diff --git a/bin/gensquashfs/src/mkfs.c b/bin/gensquashfs/src/mkfs.c
index cdef359..de291fa 100644
--- a/bin/gensquashfs/src/mkfs.c
+++ b/bin/gensquashfs/src/mkfs.c
@@ -160,9 +160,11 @@ int main(int argc, char **argv)
 	}
 
 	if (opt.sortfile != NULL) {
-		sortfile = istream_open_file(opt.sortfile);
-		if (sortfile == NULL)
+		int ret = istream_open_file(&sortfile, opt.sortfile);
+		if (ret) {
+			sqfs_perror(opt.sortfile, NULL, ret);
 			goto out;
+		}
 	}
 
 	if (opt.infile == NULL) {
diff --git a/bin/rdsquashfs/src/fill_files.c b/bin/rdsquashfs/src/fill_files.c
index e692ee3..f0ad7e2 100644
--- a/bin/rdsquashfs/src/fill_files.c
+++ b/bin/rdsquashfs/src/fill_files.c
@@ -145,9 +145,11 @@ static int fill_files(sqfs_data_reader_t *data, int flags)
 		openflags |= SQFS_FILE_OPEN_NO_SPARSE;
 
 	for (i = 0; i < num_files; ++i) {
-		fp = ostream_open_file(files[i].path, openflags);
-		if (fp == NULL)
+		ret = ostream_open_file(&fp, files[i].path, openflags);
+		if (ret) {
+			sqfs_perror(files[i].path, NULL, ret);
 			return -1;
+		}
 
 		if (!(flags & UNPACK_QUIET))
 			printf("unpacking %s\n", files[i].path);
@@ -157,9 +159,13 @@ static int fill_files(sqfs_data_reader_t *data, int flags)
 		if (ret == 0)
 			ret = fp->flush(fp);
 
-		sqfs_drop(fp);
-		if (ret)
+		if (ret) {
+			sqfs_perror(files[i].path, "unpacking", ret);
+			sqfs_drop(fp);
 			return -1;
+		}
+
+		sqfs_drop(fp);
 	}
 
 	return 0;
diff --git a/bin/rdsquashfs/src/rdsquashfs.c b/bin/rdsquashfs/src/rdsquashfs.c
index ad85e68..77dc5ba 100644
--- a/bin/rdsquashfs/src/rdsquashfs.c
+++ b/bin/rdsquashfs/src/rdsquashfs.c
@@ -208,6 +208,7 @@ int main(int argc, char **argv)
 		break;
 	case OP_CAT: {
 		sqfs_ostream_t *fp;
+		int ret;
 
 		if (!S_ISREG(n->inode->base.mode)) {
 			fprintf(stderr, "/%s: not a regular file\n",
@@ -215,9 +216,11 @@ int main(int argc, char **argv)
 			goto out;
 		}
 
-		fp = ostream_open_stdout();
-		if (fp == NULL)
+		ret = ostream_open_stdout(&fp);
+		if (ret) {
+			sqfs_perror("stdout", "creating stream wrapper", ret);
 			goto out;
+		}
 
 		ret = sqfs_data_reader_dump(opt.cmdpath, data, n->inode,
 					    fp, super.block_size);
diff --git a/bin/sqfs2tar/src/sqfs2tar.c b/bin/sqfs2tar/src/sqfs2tar.c
index e90aa56..714f6db 100644
--- a/bin/sqfs2tar/src/sqfs2tar.c
+++ b/bin/sqfs2tar/src/sqfs2tar.c
@@ -117,9 +117,9 @@ int main(int argc, char **argv)
 
 	process_args(argc, argv);
 
-	out_file = ostream_open_stdout();
-	if (out_file == NULL) {
-		perror("changing stdout to binary mode");
+	ret = ostream_open_stdout(&out_file);
+	if (ret) {
+		sqfs_perror("stdout", "creating stream wrapper", ret);
 		goto out;
 	}
 
@@ -253,8 +253,11 @@ int main(int argc, char **argv)
 	if (terminate_archive())
 		goto out;
 
-	if (out_file->flush(out_file))
+	ret = out_file->flush(out_file);
+	if (ret) {
+		sqfs_perror(out_file->get_filename(out_file), NULL, ret);
 		goto out;
+	}
 
 	status = EXIT_SUCCESS;
 out:
diff --git a/bin/sqfs2tar/src/write_tree.c b/bin/sqfs2tar/src/write_tree.c
index e578a9f..dc3ac72 100644
--- a/bin/sqfs2tar/src/write_tree.c
+++ b/bin/sqfs2tar/src/write_tree.c
@@ -119,6 +119,8 @@ static int write_tree_dfs(const sqfs_tree_node_t *n)
 		if (lnk != NULL) {
 			ret = write_hard_link(out_file, &sb, name, lnk->target,
 					      record_counter++);
+			if (ret != 0)
+				sqfs_perror(name, "writing hard link", ret);
 			sqfs_free(name);
 			return ret;
 		}
@@ -143,10 +145,13 @@ static int write_tree_dfs(const sqfs_tree_node_t *n)
 			       record_counter++);
 	sqfs_xattr_list_free(xattr);
 
-	if (ret > 0)
+	if (ret == SQFS_ERROR_UNSUPPORTED) {
+		fprintf(stderr, "WARNING: %s: unsupported file type\n", name);
 		goto out_skip;
+	}
 
 	if (ret < 0) {
+		sqfs_perror(name, "writing tar header", ret);
 		sqfs_free(name);
 		return -1;
 	}
@@ -158,7 +163,9 @@ static int write_tree_dfs(const sqfs_tree_node_t *n)
 			return -1;
 		}
 
-		if (padd_file(out_file, sb.st_size)) {
+		ret = padd_file(out_file, sb.st_size);
+		if (ret) {
+			sqfs_perror(name, NULL, ret);
 			sqfs_free(name);
 			return -1;
 		}
diff --git a/bin/sqfsdiff/src/extract.c b/bin/sqfsdiff/src/extract.c
index 43e9b97..d51096f 100644
--- a/bin/sqfsdiff/src/extract.c
+++ b/bin/sqfsdiff/src/extract.c
@@ -11,6 +11,7 @@ static int extract(sqfs_data_reader_t *data, const sqfs_inode_generic_t *inode,
 {
 	char *ptr, *temp;
 	sqfs_ostream_t *fp;
+	int ret;
 
 	temp = alloca(strlen(prefix) + strlen(path) + 2);
 	sprintf(temp, "%s/%s", prefix, path);
@@ -21,9 +22,9 @@ static int extract(sqfs_data_reader_t *data, const sqfs_inode_generic_t *inode,
 		return -1;
 	*ptr = '/';
 
-	fp = ostream_open_file(temp, SQFS_FILE_OPEN_OVERWRITE);
-	if (fp == NULL) {
-		perror(temp);
+	ret = ostream_open_file(&fp, temp, SQFS_FILE_OPEN_OVERWRITE);
+	if (ret) {
+		sqfs_perror(temp, NULL, ret);
 		return -1;
 	}
 
@@ -32,7 +33,13 @@ static int extract(sqfs_data_reader_t *data, const sqfs_inode_generic_t *inode,
 		return -1;
 	}
 
-	fp->flush(fp);
+	ret = fp->flush(fp);
+	if (ret) {
+		sqfs_perror(fp->get_filename(fp), NULL, ret);
+		sqfs_drop(fp);
+		return -1;
+	}
+
 	sqfs_drop(fp);
 	return 0;
 }
diff --git a/bin/tar2sqfs/src/tar2sqfs.c b/bin/tar2sqfs/src/tar2sqfs.c
index f7ed060..ed671f5 100644
--- a/bin/tar2sqfs/src/tar2sqfs.c
+++ b/bin/tar2sqfs/src/tar2sqfs.c
@@ -12,12 +12,15 @@ int main(int argc, char **argv)
 	sqfs_istream_t *input_file = NULL;
 	dir_iterator_t *tar = NULL;
 	sqfs_writer_t sqfs;
+	int ret;
 
 	process_args(argc, argv);
 
-	input_file = istream_open_stdin();
-	if (input_file == NULL)
+	ret = istream_open_stdin(&input_file);
+	if (ret) {
+		sqfs_perror("stdint", "creating stream wrapper", ret);
 		return EXIT_FAILURE;
+	}
 
 	tar = tar_open_stream(input_file);
 	sqfs_drop(input_file);
diff --git a/include/io/file.h b/include/io/file.h
index 5065619..e7ffb0d 100644
--- a/include/io/file.h
+++ b/include/io/file.h
@@ -22,13 +22,15 @@ extern "C" {
  * of cleaning it up. On failure, the handle remains usable, and ownership
  * remains with the caller.
  *
+ * @param out Returns a pointer to an input stream on success.
  * @param path The name to associate with the handle.
  * @param fd A native file handle.
  *
- * @return A pointer to an output stream on success, NULL on failure.
+ * @return Zero on success, a negative @ref SQFS_ERROR number on failure
  */
 SQFS_INTERNAL
-sqfs_istream_t *istream_open_handle(const char *path, sqfs_file_handle_t fd);
+int istream_open_handle(sqfs_istream_t **out, const char *path,
+			sqfs_file_handle_t fd);
 
 /**
  * @brief Create an output stream that writes to an OS native file handle.
@@ -40,26 +42,27 @@ sqfs_istream_t *istream_open_handle(const char *path, sqfs_file_handle_t fd);
  * Otherwise, it tries to use seek/truncate style APIs to create sparse output
  * files.
  *
+ * @param out Returns a pointer to an output stream on success.
  * @param path The name to associate with the handle.
  * @param fd A native file handle.
  * @param flags A combination of flags.
  *
- * @return A pointer to an output stream on success, NULL on failure.
+ * @return Zero on success, a negative @ref SQFS_ERROR number on failure
  */
-SQFS_INTERNAL sqfs_ostream_t *ostream_open_handle(const char *path,
-						  sqfs_file_handle_t hnd,
-						  int flags);
+SQFS_INTERNAL int ostream_open_handle(sqfs_ostream_t **out, const char *path,
+				      sqfs_file_handle_t hnd, int flags);
 
 /**
  * @brief Create an input stream that reads from a file.
  *
  * @memberof sqfs_istream_t
  *
+ * @param out Returns a pointer to an input stream on success.
  * @param path A path to the file to open or create.
  *
- * @return A pointer to an output stream on success, NULL on failure.
+ * @return Zero on success, a negative @ref SQFS_ERROR number on failure
  */
-SQFS_INTERNAL sqfs_istream_t *istream_open_file(const char *path);
+SQFS_INTERNAL int istream_open_file(sqfs_istream_t **out, const char *path);
 
 /**
  * @brief Create an output stream that writes to a file.
@@ -75,12 +78,14 @@ SQFS_INTERNAL sqfs_istream_t *istream_open_file(const char *path);
  * Otherwise, it tries to use seek/truncate style APIs to create sparse output
  * files.
  *
+ * @param out Returns a pointer to an output stream on success.
  * @param path A path to the file to open or create.
  * @param flags A combination of flags controling how to open/create the file.
  *
- * @return A pointer to an output stream on success, NULL on failure.
+ * @return Zero on success, a negative @ref SQFS_ERROR number on failure
  */
-SQFS_INTERNAL sqfs_ostream_t *ostream_open_file(const char *path, int flags);
+SQFS_INTERNAL int ostream_open_file(sqfs_ostream_t **out,
+				    const char *path, int flags);
 
 #ifdef __cplusplus
 }
diff --git a/include/io/std.h b/include/io/std.h
index f622491..c5dddfa 100644
--- a/include/io/std.h
+++ b/include/io/std.h
@@ -18,18 +18,22 @@ extern "C" {
  *
  * @memberof sqfs_istream_t
  *
- * @return A pointer to an input stream on success, NULL on failure.
+ * @param out Returns a pointer to an input stream on success.
+ *
+ * @return Zero on success, a negative @ref SQFS_ERROR number on failure
  */
-SQFS_INTERNAL sqfs_istream_t *istream_open_stdin(void);
+SQFS_INTERNAL int istream_open_stdin(sqfs_istream_t **out);
 
 /**
  * @brief Create an output stream that writes to standard output.
  *
  * @memberof sqfs_ostream_t
  *
- * @return A pointer to an output stream on success, NULL on failure.
+ * @param out Returns a pointer to an output stream on success.
+ *
+ * @return Zero on success, a negative @ref SQFS_ERROR number on failure
  */
-SQFS_INTERNAL sqfs_ostream_t *ostream_open_stdout(void);
+SQFS_INTERNAL int ostream_open_stdout(sqfs_ostream_t **out);
 
 #ifdef __cplusplus
 }
diff --git a/lib/common/src/data_reader_dump.c b/lib/common/src/data_reader_dump.c
index e3cbb87..920b2bd 100644
--- a/lib/common/src/data_reader_dump.c
+++ b/lib/common/src/data_reader_dump.c
@@ -26,8 +26,7 @@ int sqfs_data_reader_dump(const char *name, sqfs_data_reader_t *data,
 		diff = (filesz < block_size) ? filesz : block_size;
 
 		if (SQFS_IS_SPARSE_BLOCK(inode->extra[i])) {
-			if (fp->append(fp, NULL, diff))
-				return -1;
+			err = fp->append(fp, NULL, diff);
 		} else {
 			err = sqfs_data_reader_get_block(data, inode, i,
 							 &chunk_size, &chunk);
@@ -38,11 +37,11 @@ int sqfs_data_reader_dump(const char *name, sqfs_data_reader_t *data,
 
 			err = fp->append(fp, chunk, chunk_size);
 			free(chunk);
-
-			if (err)
-				return -1;
 		}
 
+		if (err)
+			goto fail_io;
+
 		filesz -= diff;
 	}
 
@@ -58,8 +57,11 @@ int sqfs_data_reader_dump(const char *name, sqfs_data_reader_t *data,
 		free(chunk);
 
 		if (err)
-			return -1;
+			goto fail_io;
 	}
 
 	return 0;
+fail_io:
+	sqfs_perror(fp->get_filename(fp), "writing data block", err);
+	return -1;
 }
diff --git a/lib/common/src/perror.c b/lib/common/src/perror.c
index 53a8c16..5f62748 100644
--- a/lib/common/src/perror.c
+++ b/lib/common/src/perror.c
@@ -8,9 +8,22 @@
 
 #include <stdio.h>
 
+#if defined(_WIN32) || defined(__WINDOWS__)
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#else
+#include <errno.h>
+#include <string.h>
+#endif
+
 void sqfs_perror(const char *file, const char *action, int error_code)
 {
 	const char *errstr;
+#if defined(_WIN32) || defined(__WINDOWS__)
+	DWORD syserror = GetLastError();
+#else
+	int syserror = errno;
+#endif
 
 	switch (error_code) {
 	case SQFS_ERROR_ALLOC:
@@ -76,4 +89,24 @@ void sqfs_perror(const char *file, const char *action, int error_code)
 		fprintf(stderr, "%s: ", action);
 
 	fprintf(stderr, "%s.\n", errstr);
+
+	if (error_code == SQFS_ERROR_IO) {
+#if defined(_WIN32) || defined(__WINDOWS__)
+		LPVOID msg = NULL;
+
+		FormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER |
+			       FORMAT_MESSAGE_FROM_SYSTEM |
+			       FORMAT_MESSAGE_IGNORE_INSERTS,
+			       NULL, syserror,
+			       MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+			       (LPTSTR)&msg, 0, NULL);
+
+		fprintf(stderr, "OS error: %s\n", (const char *)msg);
+
+		if (msg != NULL)
+			LocalFree(msg);
+#else
+		fprintf(stderr, "OS error: %s\n", strerror(syserror));
+#endif
+	}
 }
diff --git a/lib/io/src/get_line.c b/lib/io/src/get_line.c
index ad37be6..3178592 100644
--- a/lib/io/src/get_line.c
+++ b/lib/io/src/get_line.c
@@ -6,6 +6,7 @@
  */
 #include "internal.h"
 #include "sqfs/io.h"
+#include "sqfs/error.h"
 
 static void ltrim(char *buffer)
 {
@@ -44,17 +45,17 @@ int istream_get_line(sqfs_istream_t *strm, char **out,
 {
 	char *line = NULL, *new;
 	size_t line_len = 0;
+	int err;
 
 	for (;;) {
 		bool have_line = false;
 		size_t i, count, avail;
 		const sqfs_u8 *ptr;
-		int ret;
 
-		ret = strm->get_buffered_data(strm, &ptr, &avail, 0);
-		if (ret < 0)
-			goto fail_free;
-		if (ret > 0) {
+		err = strm->get_buffered_data(strm, &ptr, &avail, 0);
+		if (err < 0)
+			goto fail;
+		if (err > 0) {
 			if (line_len == 0)
 				goto out_eof;
 
@@ -78,8 +79,10 @@ int istream_get_line(sqfs_istream_t *strm, char **out,
 		}
 
 		new = realloc(line, line_len + count + 1);
-		if (new == NULL)
-			goto fail_errno;
+		if (new == NULL) {
+			err = SQFS_ERROR_ALLOC;
+			goto fail;
+		}
 
 		line = new;
 		memcpy(line + line_len, ptr, count);
@@ -108,13 +111,13 @@ int istream_get_line(sqfs_istream_t *strm, char **out,
 
 	*out = line;
 	return 0;
-fail_errno:
-	fprintf(stderr, "%s: " PRI_SZ ": %s.\n", strm->get_filename(strm),
-		*line_num, strerror(errno));
-fail_free:
+fail: {
+	int temp = errno;
 	free(line);
 	*out = NULL;
-	return -1;
+	errno = temp;
+	return err;
+}
 out_eof:
 	free(line);
 	*out = NULL;
diff --git a/lib/io/src/unix/istream.c b/lib/io/src/unix/istream.c
index ca9a183..5005a69 100644
--- a/lib/io/src/unix/istream.c
+++ b/lib/io/src/unix/istream.c
@@ -6,6 +6,7 @@
  */
 #include "../internal.h"
 #include "sqfs/io.h"
+#include "sqfs/error.h"
 
 typedef struct {
 	sqfs_istream_t base;
@@ -46,9 +47,7 @@ static int precache(sqfs_istream_t *strm)
 		if (ret < 0) {
 			if (errno == EINTR)
 				continue;
-
-			perror(file->path);
-			return -1;
+			return SQFS_ERROR_IO;
 		}
 
 		file->buffer_used += ret;
@@ -90,76 +89,72 @@ static void file_advance_buffer(sqfs_istream_t *strm, size_t count)
 
 static const char *file_get_filename(sqfs_istream_t *strm)
 {
-	file_istream_t *file = (file_istream_t *)strm;
-
-	return file->path;
+	return ((file_istream_t *)strm)->path;
 }
 
 static void file_destroy(sqfs_object_t *obj)
 {
 	file_istream_t *file = (file_istream_t *)obj;
 
-	if (file->fd != STDIN_FILENO)
-		close(file->fd);
-
+	close(file->fd);
 	free(file->path);
 	free(file);
 }
 
-sqfs_istream_t *istream_open_handle(const char *path, int fd)
+int istream_open_handle(sqfs_istream_t **out, const char *path,
+			sqfs_file_handle_t fd)
 {
 	file_istream_t *file = calloc(1, sizeof(*file));
 	sqfs_istream_t *strm = (sqfs_istream_t *)file;
 
-	if (file == NULL) {
-		perror(path);
-		return NULL;
-	}
+	if (file == NULL)
+		return SQFS_ERROR_ALLOC;
 
 	sqfs_object_init(file, file_destroy, NULL);
 
 	file->path = strdup(path);
 	if (file->path == NULL) {
-		perror(path);
-		goto fail_free;
+		int temp = errno;
+		free(file);
+		errno = temp;
+		return SQFS_ERROR_ALLOC;
 	}
 
 	file->fd = dup(fd);
 	if (file->fd < 0) {
-		perror(path);
-		goto fail_path;
+		int temp = errno;
+		free(file->path);
+		free(file);
+		errno = temp;
+		return SQFS_ERROR_IO;
 	}
 	close(fd);
 
 	strm->get_buffered_data = file_get_buffered_data;
 	strm->advance_buffer = file_advance_buffer;
 	strm->get_filename = file_get_filename;
-	return strm;
-fail_path:
-	free(file->path);
-fail_free:
-	free(file);
-	return NULL;
+
+	*out = strm;
+	return 0;
 }
 
-sqfs_istream_t *istream_open_file(const char *path)
+int istream_open_file(sqfs_istream_t **out, const char *path)
 {
 	sqfs_file_handle_t fd;
-	sqfs_istream_t *out;
+	int ret;
 
-	if (sqfs_open_native_file(&fd, path, SQFS_FILE_OPEN_READ_ONLY)) {
-		perror(path);
-		return NULL;
-	}
+	ret = sqfs_open_native_file(&fd, path, SQFS_FILE_OPEN_READ_ONLY);
+	if (ret)
+		return ret;
 
-	out = istream_open_handle(path, fd);
-	if (out == NULL)
+	ret = istream_open_handle(out, path, fd);
+	if (ret != 0)
 		close(fd);
 
-	return out;
+	return ret;
 }
 
-sqfs_istream_t *istream_open_stdin(void)
+int istream_open_stdin(sqfs_istream_t **out)
 {
-	return istream_open_handle("stdin", STDIN_FILENO);
+	return istream_open_handle(out, "stdin", STDIN_FILENO);
 }
diff --git a/lib/io/src/unix/ostream.c b/lib/io/src/unix/ostream.c
index 52a566a..a97d8f3 100644
--- a/lib/io/src/unix/ostream.c
+++ b/lib/io/src/unix/ostream.c
@@ -6,6 +6,7 @@
  */
 #include "../internal.h"
 #include "sqfs/io.h"
+#include "sqfs/error.h"
 
 typedef struct {
 	sqfs_ostream_t base;
@@ -23,15 +24,14 @@ static int write_all(file_ostream_t *file, const sqfs_u8 *data, size_t size)
 		ssize_t ret = write(file->fd, data, size);
 
 		if (ret == 0) {
-			fprintf(stderr, "%s: truncated write.\n", file->path);
-			return -1;
+			errno = EPIPE;
+			return SQFS_ERROR_IO;
 		}
 
 		if (ret < 0) {
 			if (errno == EINTR)
 				continue;
-			perror(file->path);
-			return -1;
+			return SQFS_ERROR_IO;
 		}
 
 		file->size += ret;
@@ -46,6 +46,7 @@ static int realize_sparse(file_ostream_t *file)
 {
 	unsigned char *buffer;
 	size_t diff, bufsz;
+	int ret;
 
 	if (file->sparse_count == 0)
 		return 0;
@@ -54,15 +55,18 @@ static int realize_sparse(file_ostream_t *file)
 		bufsz = file->sparse_count > 1024 ? 1024 : file->sparse_count;
 		buffer = calloc(1, bufsz);
 		if (buffer == NULL)
-			goto fail;
+			return SQFS_ERROR_ALLOC;
 
 		while (file->sparse_count > 0) {
 			diff = file->sparse_count > (off_t)bufsz ?
 				bufsz : (size_t)file->sparse_count;
 
-			if (write_all(file, buffer, diff)) {
+			ret = write_all(file, buffer, diff);
+			if (ret) {
+				int temp = errno;
 				free(buffer);
-				return -1;
+				errno = temp;
+				return ret;
 			}
 
 			file->sparse_count -= diff;
@@ -71,35 +75,31 @@ static int realize_sparse(file_ostream_t *file)
 		free(buffer);
 	} else {
 		if (lseek(file->fd, file->sparse_count, SEEK_CUR) == (off_t)-1)
-			goto fail;
+			return SQFS_ERROR_IO;
 
 		if (ftruncate(file->fd, file->size) != 0)
-			goto fail;
+			return SQFS_ERROR_IO;
 
 		file->sparse_count = 0;
 	}
 
 	return 0;
-fail:
-	perror(file->path);
-	return -1;
 }
 
 static int file_append(sqfs_ostream_t *strm, const void *data, size_t size)
 {
 	file_ostream_t *file = (file_ostream_t *)strm;
+	int ret;
 
-	if (size == 0)
-		return 0;
-
-	if (data == NULL) {
+	if (size == 0 || data == NULL) {
 		file->sparse_count += size;
 		file->size += size;
 		return 0;
 	}
 
-	if (realize_sparse(file))
-		return -1;
+	ret = realize_sparse(file);
+	if (ret)
+		return ret;
 
 	return write_all(file, data, size);
 }
@@ -107,15 +107,15 @@ static int file_append(sqfs_ostream_t *strm, const void *data, size_t size)
 static int file_flush(sqfs_ostream_t *strm)
 {
 	file_ostream_t *file = (file_ostream_t *)strm;
+	int ret;
 
-	if (realize_sparse(file))
-		return -1;
+	ret = realize_sparse(file);
+	if (ret)
+		return ret;
 
 	if (fsync(file->fd) != 0) {
-		if (errno == EINVAL)
-			return 0;
-		perror(file->path);
-		return -1;
+		if (errno != EINVAL)
+			return SQFS_ERROR_IO;
 	}
 
 	return 0;
@@ -132,33 +132,36 @@ static void file_destroy(sqfs_object_t *obj)
 
 static const char *file_get_filename(sqfs_ostream_t *strm)
 {
-	file_ostream_t *file = (file_ostream_t *)strm;
-
-	return file->path;
+	return ((file_ostream_t *)strm)->path;
 }
 
-sqfs_ostream_t *ostream_open_handle(const char *path, int fd, int flags)
+int ostream_open_handle(sqfs_ostream_t **out, const char *path,
+			sqfs_file_handle_t fd, int flags)
 {
 	file_ostream_t *file = calloc(1, sizeof(*file));
 	sqfs_ostream_t *strm = (sqfs_ostream_t *)file;
 
-	if (file == NULL) {
-		perror(path);
-		return NULL;
-	}
+	*out = NULL;
+	if (file == NULL)
+		return SQFS_ERROR_ALLOC;
 
 	sqfs_object_init(file, file_destroy, NULL);
 
 	file->path = strdup(path);
 	if (file->path == NULL) {
-		perror(path);
-		goto fail_free;
+		int temp = errno;
+		free(file);
+		errno = temp;
+		return SQFS_ERROR_ALLOC;
 	}
 
 	file->fd = dup(fd);
 	if (file->fd < 0) {
-		perror(path);
-		goto fail_path;
+		int temp = errno;
+		free(file->path);
+		free(file);
+		errno = temp;
+		return SQFS_ERROR_IO;
 	}
 
 	close(fd);
@@ -167,33 +170,34 @@ sqfs_ostream_t *ostream_open_handle(const char *path, int fd, int flags)
 	strm->append = file_append;
 	strm->flush = file_flush;
 	strm->get_filename = file_get_filename;
-	return strm;
-fail_path:
-	free(file->path);
-fail_free:
-	free(file);
-	return NULL;
+
+	*out = strm;
+	return 0;
 }
 
-sqfs_ostream_t *ostream_open_file(const char *path, int flags)
+int ostream_open_file(sqfs_ostream_t **out, const char *path, int flags)
 {
 	sqfs_file_handle_t fd;
-	sqfs_ostream_t *out;
+	int ret;
 
-	if (sqfs_open_native_file(&fd, path, flags)) {
-		perror(path);
-		return NULL;
-	}
+	*out = NULL;
+	ret = sqfs_open_native_file(&fd, path, flags);
+	if (ret)
+		return ret;
 
-	out = ostream_open_handle(path, fd, flags);
-	if (out == NULL)
+	ret = ostream_open_handle(out, path, fd, flags);
+	if (ret) {
+		int temp = errno;
 		close(fd);
+		errno = temp;
+		return ret;
+	}
 
-	return out;
+	return 0;
 }
 
-sqfs_ostream_t *ostream_open_stdout(void)
+int ostream_open_stdout(sqfs_ostream_t **out)
 {
-	return ostream_open_handle("stdout", STDOUT_FILENO,
+	return ostream_open_handle(out, "stdout", STDOUT_FILENO,
 				   SQFS_FILE_OPEN_NO_SPARSE);
 }
diff --git a/lib/io/src/win32/istream.c b/lib/io/src/win32/istream.c
index 7cc7144..1a4f4db 100644
--- a/lib/io/src/win32/istream.c
+++ b/lib/io/src/win32/istream.c
@@ -6,6 +6,7 @@
  */
 #include "../internal.h"
 #include "sqfs/io.h"
+#include "sqfs/error.h"
 
 #define WIN32_LEAN_AND_MEAN
 #include <windows.h>
@@ -52,8 +53,7 @@ static int precache(sqfs_istream_t *strm)
 			}
 
 			SetLastError(error);
-			w32_perror(file->path);
-			return -1;
+			return SQFS_ERROR_IO;
 		}
 
 		if (actual == 0) {
@@ -112,31 +112,34 @@ static void file_destroy(sqfs_object_t *obj)
 	free(file);
 }
 
-sqfs_istream_t *istream_open_handle(const char *path, HANDLE hnd)
+int istream_open_handle(sqfs_istream_t **out, const char *path, HANDLE hnd)
 {
 	file_istream_t *file = calloc(1, sizeof(*file));
 	sqfs_istream_t *strm = (sqfs_istream_t *)file;
 	BOOL ret;
 
-	if (file == NULL) {
-		perror(path);
-		return NULL;
-	}
+	if (file == NULL)
+		return SQFS_ERROR_ALLOC;
 
 	sqfs_object_init(file, file_destroy, NULL);
 
 	file->path = strdup(path);
 	if (file->path == NULL) {
-		perror(path);
-		goto fail_free;
+		DWORD temp = GetLastError();
+		free(file);
+		SetLastError(temp);
+		return SQFS_ERROR_ALLOC;
 	}
 
 	ret = DuplicateHandle(GetCurrentProcess(), hnd,
 			      GetCurrentProcess(), &file->hnd,
 			      0, FALSE, DUPLICATE_SAME_ACCESS);
 	if (!ret) {
-		w32_perror(path);
-		goto fail_path;
+		DWORD temp = GetLastError();
+		free(file->path);
+		free(file);
+		SetLastError(temp);
+		return SQFS_ERROR_IO;
 	}
 
 	CloseHandle(hnd);
@@ -144,34 +147,34 @@ sqfs_istream_t *istream_open_handle(const char *path, HANDLE hnd)
 	strm->get_buffered_data = file_get_buffered_data;
 	strm->advance_buffer = file_advance_buffer;
 	strm->get_filename = file_get_filename;
-	return strm;
-fail_path:
-	free(file->path);
-fail_free:
-	free(file);
-	return NULL;
+
+	*out = strm;
+	return 0;
 }
 
-sqfs_istream_t *istream_open_file(const char *path)
+int istream_open_file(sqfs_istream_t **out, const char *path)
 {
 	sqfs_file_handle_t hnd;
-	sqfs_istream_t *out;
+	int ret;
 
-	if (sqfs_open_native_file(&hnd, path, SQFS_FILE_OPEN_READ_ONLY)) {
-		w32_perror(path);
-		return NULL;
-	}
+	ret = sqfs_open_native_file(&hnd, path, SQFS_FILE_OPEN_READ_ONLY);
+	if (ret)
+		return ret;
 
-	out = istream_open_handle(path, hnd);
-	if (out == NULL)
+	ret = istream_open_handle(out, path, hnd);
+	if (ret) {
+		DWORD temp = GetLastError();
 		CloseHandle(hnd);
+		SetLastError(temp);
+		return ret;
+	}
 
-	return out;
+	return 0;
 }
 
-sqfs_istream_t *istream_open_stdin(void)
+int istream_open_stdin(sqfs_istream_t **out)
 {
 	HANDLE hnd = GetStdHandle(STD_INPUT_HANDLE);
 
-	return istream_open_handle("stdin", hnd);
+	return istream_open_handle(out, "stdin", hnd);
 }
diff --git a/lib/io/src/win32/ostream.c b/lib/io/src/win32/ostream.c
index 5b584e5..b2ba599 100644
--- a/lib/io/src/win32/ostream.c
+++ b/lib/io/src/win32/ostream.c
@@ -6,6 +6,7 @@
  */
 #include "../internal.h"
 #include "sqfs/io.h"
+#include "sqfs/error.h"
 
 #define WIN32_LEAN_AND_MEAN
 #include <windows.h>
@@ -23,10 +24,8 @@ static int write_data(file_ostream_t *file, const void *data, size_t size)
 	DWORD diff;
 
 	while (size > 0) {
-		if (!WriteFile(file->hnd, data, size, &diff, NULL)) {
-			w32_perror(file->path);
-			return -1;
-		}
+		if (!WriteFile(file->hnd, data, size, &diff, NULL))
+			return SQFS_ERROR_IO;
 
 		size -= diff;
 		data = (const char *)data + diff;
@@ -40,6 +39,7 @@ static int realize_sparse(file_ostream_t *file)
 	size_t bufsz, diff;
 	LARGE_INTEGER pos;
 	void *buffer;
+	int ret;
 
 	if (file->sparse_count == 0)
 		return 0;
@@ -48,18 +48,19 @@ static int realize_sparse(file_ostream_t *file)
 		bufsz = file->sparse_count > 1024 ? 1024 : file->sparse_count;
 		buffer = calloc(1, bufsz);
 
-		if (buffer == NULL) {
-			fputs("out-of-memory\n", stderr);
-			return -1;
-		}
+		if (buffer == NULL)
+			return SQFS_ERROR_ALLOC;
 
 		while (file->sparse_count > 0) {
 			diff = file->sparse_count > bufsz ?
 				bufsz : file->sparse_count;
 
-			if (write_data(file, buffer, diff)) {
+			ret = write_data(file, buffer, diff);
+			if (ret) {
+				DWORD temp = GetLastError();
 				free(buffer);
-				return -1;
+				SetLastError(temp);
+				return ret;
 			}
 
 			file->sparse_count -= diff;
@@ -70,34 +71,30 @@ static int realize_sparse(file_ostream_t *file)
 		pos.QuadPart = file->sparse_count;
 
 		if (!SetFilePointerEx(file->hnd, pos, NULL, FILE_CURRENT))
-			goto fail;
+			return SQFS_ERROR_IO;
 
 		if (!SetEndOfFile(file->hnd))
-			goto fail;
+			return SQFS_ERROR_IO;
 
 		file->sparse_count = 0;
 	}
 
 	return 0;
-fail:
-	w32_perror(file->path);
-	return -1;
 }
 
 static int file_append(sqfs_ostream_t *strm, const void *data, size_t size)
 {
 	file_ostream_t *file = (file_ostream_t *)strm;
+	int ret;
 
-	if (size == 0)
-		return 0;
-
-	if (data == NULL) {
+	if (size == 0 || data == NULL) {
 		file->sparse_count += size;
 		return 0;
 	}
 
-	if (realize_sparse(file))
-		return -1;
+	ret = realize_sparse(file);
+	if (ret)
+		return ret;
 
 	return write_data(file, data, size);
 }
@@ -105,14 +102,14 @@ static int file_append(sqfs_ostream_t *strm, const void *data, size_t size)
 static int file_flush(sqfs_ostream_t *strm)
 {
 	file_ostream_t *file = (file_ostream_t *)strm;
+	int ret;
 
-	if (realize_sparse(file))
-		return -1;
+	ret = realize_sparse(file);
+	if (ret)
+		return ret;
 
-	if (!FlushFileBuffers(file->hnd)) {
-		w32_perror(file->path);
-		return -1;
-	}
+	if (!FlushFileBuffers(file->hnd))
+		return SQFS_ERROR_IO;
 
 	return 0;
 }
@@ -128,36 +125,36 @@ static void file_destroy(sqfs_object_t *obj)
 
 static const char *file_get_filename(sqfs_ostream_t *strm)
 {
-	file_ostream_t *file = (file_ostream_t *)strm;
-
-	return file->path;
+	return ((file_ostream_t *)strm)->path;
 }
 
-sqfs_ostream_t *ostream_open_handle(const char *path, HANDLE hnd, int flags)
+int ostream_open_handle(sqfs_ostream_t **out, const char *path,
+			sqfs_file_handle_t hnd, int flags)
 {
 	file_ostream_t *file = calloc(1, sizeof(*file));
 	sqfs_ostream_t *strm = (sqfs_ostream_t *)file;
 	BOOL ret;
 
-	if (file == NULL) {
-		perror(path);
-		return NULL;
-	}
+	if (file == NULL)
+		return SQFS_ERROR_ALLOC;
 
 	sqfs_object_init(file, file_destroy, NULL);
 
 	file->path = strdup(path);
 	if (file->path == NULL) {
-		perror(path);
-		goto fail_free;
+		free(file);
+		return SQFS_ERROR_ALLOC;
 	}
 
 	ret = DuplicateHandle(GetCurrentProcess(), hnd,
 			      GetCurrentProcess(), &file->hnd,
 			      0, FALSE, DUPLICATE_SAME_ACCESS);
 	if (!ret) {
-		w32_perror(path);
-		goto fail_path;
+		DWORD temp = GetLastError();
+		free(file->path);
+		free(file);
+		SetLastError(temp);
+		return SQFS_ERROR_IO;
 	}
 
 	CloseHandle(hnd);
@@ -166,39 +163,36 @@ sqfs_ostream_t *ostream_open_handle(const char *path, HANDLE hnd, int flags)
 	strm->append = file_append;
 	strm->flush = file_flush;
 	strm->get_filename = file_get_filename;
-	return strm;
-fail_path:
-	free(file->path);
-fail_free:
-	free(file);
-	return NULL;
+
+	*out = strm;
+	return 0;
 }
 
-sqfs_ostream_t *ostream_open_file(const char *path, int flags)
+int ostream_open_file(sqfs_ostream_t **out, const char *path, int flags)
 {
 	sqfs_file_handle_t hnd;
-	sqfs_ostream_t *out;
-
-	if (sqfs_open_native_file(&hnd, path, flags)) {
-		w32_perror(path);
-		return NULL;
-	}
+	int ret;
 
-	if (hnd == INVALID_HANDLE_VALUE) {
-		w32_perror(path);
-		return NULL;
-	}
+	*out = NULL;
+	ret = sqfs_open_native_file(&hnd, path, flags);
+	if (ret)
+		return ret;
 
-	out = ostream_open_handle(path, hnd, flags);
-	if (out == NULL)
+	ret = ostream_open_handle(out, path, hnd, flags);
+	if (ret) {
+		DWORD temp = GetLastError();
 		CloseHandle(hnd);
+		SetLastError(temp);
+		return SQFS_ERROR_IO;
+	}
 
-	return out;
+	return 0;
 }
 
-sqfs_ostream_t *ostream_open_stdout(void)
+int ostream_open_stdout(sqfs_ostream_t **out)
 {
 	HANDLE hnd = GetStdHandle(STD_OUTPUT_HANDLE);
 
-	return ostream_open_handle("stdout", hnd, SQFS_FILE_OPEN_NO_SPARSE);
+	return ostream_open_handle(out, "stdout", hnd,
+				   SQFS_FILE_OPEN_NO_SPARSE);
 }
diff --git a/lib/io/src/xfrm/istream.c b/lib/io/src/xfrm/istream.c
index c499f6c..ee4b5bd 100644
--- a/lib/io/src/xfrm/istream.c
+++ b/lib/io/src/xfrm/istream.c
@@ -6,6 +6,7 @@
  */
 #include "../internal.h"
 #include "sqfs/io.h"
+#include "sqfs/error.h"
 
 typedef struct istream_xfrm_t {
 	sqfs_istream_t base;
@@ -52,11 +53,8 @@ static int precache(sqfs_istream_t *base)
 					       BUFSZ - out_off,
 					       &in_off, &out_off, mode);
 
-		if (ret == XFRM_STREAM_ERROR) {
-			fprintf(stderr, "%s: internal error in decompressor.\n",
-				base->get_filename(base));
-			return -1;
-		}
+		if (ret == XFRM_STREAM_ERROR)
+			return SQFS_ERROR_COMPRESSOR;
 
 		xfrm->buffer_used = out_off;
 		xfrm->wrapped->advance_buffer(xfrm->wrapped, in_off);
diff --git a/lib/io/src/xfrm/ostream.c b/lib/io/src/xfrm/ostream.c
index 4c77f42..c035f2a 100644
--- a/lib/io/src/xfrm/ostream.c
+++ b/lib/io/src/xfrm/ostream.c
@@ -6,6 +6,7 @@
  */
 #include "../internal.h"
 #include "sqfs/io.h"
+#include "sqfs/error.h"
 
 typedef struct ostream_xfrm_t {
 	sqfs_ostream_t base;
@@ -26,7 +27,7 @@ static int flush_inbuf(ostream_xfrm_t *xfrm, bool finish)
 	const int mode = finish ? XFRM_STREAM_FLUSH_FULL :
 		XFRM_STREAM_FLUSH_NONE;
 	sqfs_u32 off_in = 0, off_out = 0;
-	int ret;
+	int ret, ioret;
 
 	while (finish || off_in < avail_in) {
 		ret = xfrm->xfrm->process_data(xfrm->xfrm,
@@ -36,15 +37,13 @@ static int flush_inbuf(ostream_xfrm_t *xfrm, bool finish)
 					       avail_out - off_out,
 					       &off_in, &off_out, mode);
 
-		if (ret == XFRM_STREAM_ERROR) {
-			fprintf(stderr,
-				"%s: internal error in compressor.\n",
-				xfrm->wrapped->get_filename(xfrm->wrapped));
-			return -1;
-		}
+		if (ret == XFRM_STREAM_ERROR)
+			return SQFS_ERROR_COMPRESSOR;
 
-		if (xfrm->wrapped->append(xfrm->wrapped, xfrm->outbuf, off_out))
-			return -1;
+		ioret = xfrm->wrapped->append(xfrm->wrapped,
+					      xfrm->outbuf, off_out);
+		if (ioret)
+			return ioret;
 
 		off_out = 0;
 
@@ -53,8 +52,10 @@ static int flush_inbuf(ostream_xfrm_t *xfrm, bool finish)
 	}
 
 	if (off_out > 0) {
-		if (xfrm->wrapped->append(xfrm->wrapped, xfrm->outbuf, off_out))
-			return -1;
+		ret = xfrm->wrapped->append(xfrm->wrapped,
+					    xfrm->outbuf, off_out);
+		if (ret)
+			return ret;
 	}
 
 	if (off_in < avail_in) {
@@ -74,8 +75,9 @@ static int xfrm_append(sqfs_ostream_t *strm, const void *data, size_t size)
 
 	while (size > 0) {
 		if (xfrm->inbuf_used >= BUFSZ) {
-			if (flush_inbuf(xfrm, false))
-				return -1;
+			int ret = flush_inbuf(xfrm, false);
+			if (ret)
+				return ret;
 		}
 
 		diff = BUFSZ - xfrm->inbuf_used;
@@ -102,8 +104,9 @@ static int xfrm_flush(sqfs_ostream_t *strm)
 	ostream_xfrm_t *xfrm = (ostream_xfrm_t *)strm;
 
 	if (xfrm->inbuf_used > 0) {
-		if (flush_inbuf(xfrm, true))
-			return -1;
+		int ret = flush_inbuf(xfrm, true);
+		if (ret)
+			return ret;
 	}
 
 	return xfrm->wrapped->flush(xfrm->wrapped);
diff --git a/lib/tar/Makemodule.am b/lib/tar/Makemodule.am
index 983467e..b66d071 100644
--- a/lib/tar/Makemodule.am
+++ b/lib/tar/Makemodule.am
@@ -11,193 +11,194 @@ noinst_LIBRARIES += libtar.a
 TARDATADIR=$(top_srcdir)/lib/tar/test/data
 
 test_tar_gnu0_SOURCES = lib/tar/test/tar_simple.c
-test_tar_gnu0_LDADD = libtar.a libio.a libsquashfs.la libutil.a libcompat.a
+test_tar_gnu0_LDADD = libtar.a libio.a libcommon.a libsquashfs.la libutil.a libcompat.a
 test_tar_gnu0_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_gnu0_CPPFLAGS += -DTESTFILE=format-acceptance/gnu.tar
 
 test_tar_gnu1_SOURCES = lib/tar/test/tar_simple.c
-test_tar_gnu1_LDADD = libtar.a libio.a libsquashfs.la libutil.a libcompat.a
+test_tar_gnu1_LDADD = libtar.a libio.a libcommon.a libsquashfs.la libutil.a libcompat.a
 test_tar_gnu1_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_gnu1_CPPFLAGS += -DTESTFILE=format-acceptance/gnu-g.tar
 
 test_tar_gnu2_SOURCES = lib/tar/test/tar_simple.c
-test_tar_gnu2_LDADD = libtar.a libio.a libsquashfs.la libutil.a libcompat.a
+test_tar_gnu2_LDADD = libtar.a libio.a libcommon.a libsquashfs.la libutil.a libcompat.a
 test_tar_gnu2_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_gnu2_CPPFLAGS += -DTESTFILE=user-group-largenum/gnu.tar
 test_tar_gnu2_CPPFLAGS += -DTESTUID=0x80000000  -DTESTGID=0x80000000
 test_tar_gnu2_CPPFLAGS += -DTESTTS=1542995392
 
 test_tar_gnu3_SOURCES = lib/tar/test/tar_simple.c
-test_tar_gnu3_LDADD = libtar.a libio.a libsquashfs.la libutil.a libcompat.a
+test_tar_gnu3_LDADD = libtar.a libio.a libcommon.a libsquashfs.la libutil.a libcompat.a
 test_tar_gnu3_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_gnu3_CPPFLAGS += -DTESTFILE=negative-mtime/gnu.tar -DTESTTS=-315622800
 
 test_tar_gnu4_SOURCES = lib/tar/test/tar_simple.c
-test_tar_gnu4_LDADD = libtar.a libio.a libsquashfs.la libutil.a libcompat.a
+test_tar_gnu4_LDADD = libtar.a libio.a libcommon.a libsquashfs.la libutil.a libcompat.a
 test_tar_gnu4_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_gnu4_CPPFLAGS += -DTESTFILE=long-paths/gnu.tar -DLONG_NAME_TEST
 test_tar_gnu4_CPPFLAGS += -DTESTTS=1542909670
 
 test_tar_gnu5_SOURCES = lib/tar/test/tar_simple.c
-test_tar_gnu5_LDADD = libtar.a libio.a libsquashfs.la libutil.a libcompat.a
+test_tar_gnu5_LDADD = libtar.a libio.a libcommon.a libsquashfs.la libutil.a libcompat.a
 test_tar_gnu5_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_gnu5_CPPFLAGS += -DTESTFILE=large-mtime/gnu.tar -DTESTTS=8589934592L
 
 test_tar_gnu6_SOURCES = lib/tar/test/tar_big_file.c
-test_tar_gnu6_LDADD = libtar.a libio.a libsquashfs.la libutil.a libcompat.a
+test_tar_gnu6_LDADD = libtar.a libio.a libcommon.a libsquashfs.la libutil.a libcompat.a
 test_tar_gnu6_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_gnu6_CPPFLAGS += -DTESTFILE=file-size/gnu.tar
 
 test_tar_pax0_SOURCES = lib/tar/test/tar_simple.c
-test_tar_pax0_LDADD = libtar.a libio.a libsquashfs.la libutil.a libcompat.a
+test_tar_pax0_LDADD = libtar.a libio.a libcommon.a libsquashfs.la libutil.a libcompat.a
 test_tar_pax0_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_pax0_CPPFLAGS += -DTESTFILE=format-acceptance/pax.tar
 
 test_tar_pax1_SOURCES = lib/tar/test/tar_simple.c
-test_tar_pax1_LDADD = libtar.a libio.a libsquashfs.la libutil.a libcompat.a
+test_tar_pax1_LDADD = libtar.a libio.a libcommon.a libsquashfs.la libutil.a libcompat.a
 test_tar_pax1_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_pax1_CPPFLAGS += -DTESTFILE=user-group-largenum/pax.tar
 test_tar_pax1_CPPFLAGS += -DTESTUID=2147483648UL -DTESTGID=2147483648UL
 test_tar_pax1_CPPFLAGS += -DTESTTS=1542995392
 
 test_tar_pax2_SOURCES = lib/tar/test/tar_simple.c
-test_tar_pax2_LDADD = libtar.a libio.a libsquashfs.la libutil.a libcompat.a
+test_tar_pax2_LDADD = libtar.a libio.a libcommon.a libsquashfs.la libutil.a libcompat.a
 test_tar_pax2_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_pax2_CPPFLAGS += -DTESTFILE=large-mtime/pax.tar -DTESTTS=8589934592L
 
 test_tar_pax3_SOURCES = lib/tar/test/tar_simple.c
-test_tar_pax3_LDADD = libtar.a libio.a libsquashfs.la libutil.a libcompat.a
+test_tar_pax3_LDADD = libtar.a libio.a libcommon.a libsquashfs.la libutil.a libcompat.a
 test_tar_pax3_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_pax3_CPPFLAGS += -DTESTFILE=negative-mtime/pax.tar -DTESTTS=-315622800
 
 test_tar_pax4_SOURCES = lib/tar/test/tar_simple.c
-test_tar_pax4_LDADD = libtar.a libio.a libsquashfs.la libutil.a libcompat.a
+test_tar_pax4_LDADD = libtar.a libio.a libcommon.a libsquashfs.la libutil.a libcompat.a
 test_tar_pax4_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_pax4_CPPFLAGS += -DTESTFILE=long-paths/pax.tar
 test_tar_pax4_CPPFLAGS += -DLONG_NAME_TEST -DTESTTS=1542909670
 
 test_tar_pax5_SOURCES = lib/tar/test/tar_big_file.c
-test_tar_pax5_LDADD = libtar.a libio.a libsquashfs.la libutil.a libcompat.a
+test_tar_pax5_LDADD = libtar.a libio.a libcommon.a libsquashfs.la libutil.a libcompat.a
 test_tar_pax5_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_pax5_CPPFLAGS += -DTESTFILE=file-size/pax.tar
 
 test_tar_ustar0_SOURCES = lib/tar/test/tar_simple.c
-test_tar_ustar0_LDADD = libtar.a libio.a libsquashfs.la libutil.a libcompat.a
+test_tar_ustar0_LDADD = libtar.a libio.a libcommon.a libsquashfs.la libutil.a libcompat.a
 test_tar_ustar0_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_ustar0_CPPFLAGS += -DTESTFILE=format-acceptance/ustar.tar
 
 test_tar_ustar1_SOURCES = lib/tar/test/tar_simple.c
-test_tar_ustar1_LDADD = libtar.a libio.a libsquashfs.la libutil.a libcompat.a
+test_tar_ustar1_LDADD = libtar.a libio.a libcommon.a libsquashfs.la libutil.a libcompat.a
 test_tar_ustar1_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_ustar1_CPPFLAGS += -DTESTFILE=format-acceptance/ustar-pre-posix.tar
 
 test_tar_ustar2_SOURCES = lib/tar/test/tar_simple.c
-test_tar_ustar2_LDADD = libtar.a libio.a libsquashfs.la libutil.a libcompat.a
+test_tar_ustar2_LDADD = libtar.a libio.a libcommon.a libsquashfs.la libutil.a libcompat.a
 test_tar_ustar2_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_ustar2_CPPFLAGS += -DTESTFILE=format-acceptance/v7.tar
 
 test_tar_ustar3_SOURCES = lib/tar/test/tar_simple.c
-test_tar_ustar3_LDADD = libtar.a libio.a libsquashfs.la libutil.a libcompat.a
+test_tar_ustar3_LDADD = libtar.a libio.a libcommon.a libsquashfs.la libutil.a libcompat.a
 test_tar_ustar3_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_ustar3_CPPFLAGS += -DTESTFILE=user-group-largenum/8-digit.tar
 test_tar_ustar3_CPPFLAGS += -DTESTUID=8388608 -DTESTGID=8388608
 test_tar_ustar3_CPPFLAGS += -DTESTTS=1542995392
 
 test_tar_ustar4_SOURCES = lib/tar/test/tar_simple.c
-test_tar_ustar4_LDADD = libtar.a libio.a libsquashfs.la libutil.a libcompat.a
+test_tar_ustar4_LDADD = libtar.a libio.a libcommon.a libsquashfs.la libutil.a libcompat.a
 test_tar_ustar4_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_ustar4_CPPFLAGS += -DTESTFILE=large-mtime/12-digit.tar
 test_tar_ustar4_CPPFLAGS += -DTESTTS=8589934592L
 
 test_tar_ustar5_SOURCES = lib/tar/test/tar_simple.c
-test_tar_ustar5_LDADD = libtar.a libio.a libsquashfs.la libutil.a libcompat.a
+test_tar_ustar5_LDADD = libtar.a libio.a libcommon.a libsquashfs.la libutil.a libcompat.a
 test_tar_ustar5_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_ustar5_CPPFLAGS += -DTESTFILE=long-paths/ustar.tar
 test_tar_ustar5_CPPFLAGS += -DLONG_NAME_TEST -DTESTTS=1542909670
 
 test_tar_ustar6_SOURCES = lib/tar/test/tar_big_file.c
-test_tar_ustar6_LDADD = libtar.a libio.a libsquashfs.la libutil.a libcompat.a
+test_tar_ustar6_LDADD = libtar.a libio.a libcommon.a libsquashfs.la libutil.a libcompat.a
 test_tar_ustar6_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_ustar6_CPPFLAGS += -DTESTFILE=file-size/12-digit.tar
 
 test_tar_target_filled_SOURCES = lib/tar/test/tar_target_filled.c
-test_tar_target_filled_LDADD = libtar.a libio.a libsquashfs.la libutil.a \
-			libcompat.a
+test_tar_target_filled_LDADD = libtar.a libio.a libcommon.a libsquashfs.la \
+			libutil.a libcompat.a
 test_tar_target_filled_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 
 test_tar_sparse_gnu_SOURCES = lib/tar/test/tar_sparse_gnu.c
-test_tar_sparse_gnu_LDADD = libtar.a libio.a libsquashfs.la libutil.a \
-			libcompat.a
+test_tar_sparse_gnu_LDADD = libtar.a libio.a libcommon.a libsquashfs.la \
+			libutil.a libcompat.a
 test_tar_sparse_gnu_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 
 test_tar_sparse_gnu0_SOURCES = lib/tar/test/tar_sparse.c
-test_tar_sparse_gnu0_LDADD = libtar.a libio.a libsquashfs.la libutil.a \
-			libcompat.a
+test_tar_sparse_gnu0_LDADD = libtar.a libio.a libcommon.a libsquashfs.la \
+			libutil.a libcompat.a
 test_tar_sparse_gnu0_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_sparse_gnu0_CPPFLAGS += -DTESTFILE=sparse-files/pax-gnu0-0.tar
 
 test_tar_sparse_gnu1_SOURCES = lib/tar/test/tar_sparse.c
-test_tar_sparse_gnu1_LDADD = libtar.a libio.a libsquashfs.la libutil.a \
-			libcompat.a
+test_tar_sparse_gnu1_LDADD = libtar.a libio.a libcommon.a libsquashfs.la \
+			libutil.a libcompat.a
 test_tar_sparse_gnu1_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_sparse_gnu1_CPPFLAGS += -DTESTFILE=sparse-files/pax-gnu0-1.tar
 
 test_tar_sparse_gnu2_SOURCES = lib/tar/test/tar_sparse.c
-test_tar_sparse_gnu2_LDADD = libtar.a libio.a libsquashfs.la libutil.a \
-			libcompat.a
+test_tar_sparse_gnu2_LDADD = libtar.a libio.a libcommon.a libsquashfs.la \
+			libutil.a libcompat.a
 test_tar_sparse_gnu2_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_sparse_gnu2_CPPFLAGS += -DTESTFILE=sparse-files/pax-gnu1-0.tar
 
 test_tar_sparse_gnu3_SOURCES = lib/tar/test/tar_sparse.c
-test_tar_sparse_gnu3_LDADD = libtar.a libio.a libsquashfs.la libutil.a \
-			libcompat.a
+test_tar_sparse_gnu3_LDADD = libtar.a libio.a libcommon.a libsquashfs.la \
+			libutil.a libcompat.a
 test_tar_sparse_gnu3_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_sparse_gnu3_CPPFLAGS += -DTESTFILE=sparse-files/gnu.tar
 
 test_tar_xattr_bsd_SOURCES = lib/tar/test/tar_xattr.c
-test_tar_xattr_bsd_LDADD = libtar.a libio.a libsquashfs.la libutil.a \
-			libcompat.a
+test_tar_xattr_bsd_LDADD = libtar.a libio.a libcommon.a libsquashfs.la \
+			libutil.a libcompat.a
 test_tar_xattr_bsd_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_xattr_bsd_CPPFLAGS += -DTESTFILE=xattr/xattr-libarchive.tar
 
 test_tar_xattr_schily_SOURCES = lib/tar/test/tar_xattr.c
-test_tar_xattr_schily_LDADD = libtar.a libio.a libsquashfs.la libutil.a \
-			libcompat.a
+test_tar_xattr_schily_LDADD = libtar.a libio.a libcommon.a libsquashfs.la \
+			libutil.a libcompat.a
 test_tar_xattr_schily_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_xattr_schily_CPPFLAGS += -DTESTFILE=xattr/xattr-schily.tar
 
 test_tar_xattr_schily_bin_SOURCES = lib/tar/test/tar_xattr_bin.c
-test_tar_xattr_schily_bin_LDADD = libtar.a libio.a libsquashfs.la libutil.a \
-			libcompat.a
+test_tar_xattr_schily_bin_LDADD = libtar.a libio.a libcommon.a libsquashfs.la \
+			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_iterator_SOURCES = lib/tar/test/tar_iterator.c
-test_tar_iterator_LDADD = libtar.a libio.a libsquashfs.la libxfrm.a \
-		libutil.a libcompat.a $(XZ_LIBS) $(BZIP2_LIBS) \
+test_tar_iterator_LDADD = libtar.a libio.a libcommon.a libsquashfs.la \
+		libxfrm.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 libio.a libsquashfs.la libxfrm.a \
-		libutil.a libcompat.a $(XZ_LIBS) $(BZIP2_LIBS) \
+test_tar_iterator2_LDADD = libtar.a libio.a libcommon.a libsquashfs.la \
+		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 libio.a libsquashfs.la libxfrm.a \
-		libutil.a libcompat.a $(XZ_LIBS) $(BZIP2_LIBS) \
+test_tar_iterator3_LDADD = libtar.a libio.a libcommon.a libsquashfs.la \
+		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
-tar_fuzz_LDADD = libtar.a libio.a libsquashfs.la libutil.a libcompat.a
+tar_fuzz_LDADD = libtar.a libio.a libcommon.a libcommon.a libsquashfs.la \
+		libutil.a libcompat.a
 
 test_tar_write_simple_SOURCES = lib/tar/test/tar_write_simple.c
-test_tar_write_simple_LDADD = libtar.a libio.a libsquashfs.la libutil.a \
-		libcompat.a
+test_tar_write_simple_LDADD = libtar.a libio.a libcommon.a libsquashfs.la \
+		libutil.a libcompat.a
 test_tar_write_simple_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(TARDATADIR)
 test_tar_write_simple_CPPFLAGS += -DTESTFILE=write/simple.tar
 
diff --git a/lib/tar/src/internal.h b/lib/tar/src/internal.h
index 56613d3..4671f0b 100644
--- a/lib/tar/src/internal.h
+++ b/lib/tar/src/internal.h
@@ -12,6 +12,8 @@
 #include "tar/tar.h"
 #include "tar/format.h"
 #include "util/util.h"
+#include "sqfs/error.h"
+#include "common.h"
 
 enum {
 	PAX_SIZE = 0x001,
diff --git a/lib/tar/src/iterator.c b/lib/tar/src/iterator.c
index 93c931c..ed35b73 100644
--- a/lib/tar/src/iterator.c
+++ b/lib/tar/src/iterator.c
@@ -231,7 +231,7 @@ retry:
 
 	return 0;
 fail:
-	tar->state = ret < 0 ? SQFS_ERROR_IO : 1;
+	tar->state = ret < 0 ? ret : 1;
 	return tar->state;
 }
 
diff --git a/lib/tar/src/read_header.c b/lib/tar/src/read_header.c
index 16fc9d7..df2f56c 100644
--- a/lib/tar/src/read_header.c
+++ b/lib/tar/src/read_header.c
@@ -176,8 +176,11 @@ int read_header(sqfs_istream_t *fp, tar_header_decoded_t *out)
 
 	for (;;) {
 		ret = sqfs_istream_read(fp, &hdr, sizeof(hdr));
-		if (ret < 0)
+		if (ret < 0) {
+			sqfs_perror(fp->get_filename(fp),
+				    "reading raw tar header", ret);
 			goto fail;
+		}
 
 		if ((size_t)ret < sizeof(hdr))
 			goto out_eof;
@@ -226,7 +229,12 @@ int read_header(sqfs_istream_t *fp, tar_header_decoded_t *out)
 				goto fail;
 			if (pax_size % 512)
 				pax_size += 512 - (pax_size % 512);
-			sqfs_istream_skip(fp, pax_size);
+			ret = sqfs_istream_skip(fp, pax_size);
+			if (ret) {
+				sqfs_perror(fp->get_filename(fp),
+					    "skipping padding", ret);
+				goto fail;
+			}
 			continue;
 		case TAR_TYPE_PAX:
 			clear_header(out);
diff --git a/lib/tar/src/read_sparse_map_new.c b/lib/tar/src/read_sparse_map_new.c
index 4e317a8..e42466c 100644
--- a/lib/tar/src/read_sparse_map_new.c
+++ b/lib/tar/src/read_sparse_map_new.c
@@ -42,8 +42,10 @@ sparse_map_t *read_gnu_new_sparse(sqfs_istream_t *fp, tar_header_decoded_t *out)
 		goto fail_format;
 
 	ret = sqfs_istream_read(fp, buffer, 512);
-	if (ret < 0)
+	if (ret < 0) {
+		sqfs_perror(fp->get_filename(fp), "reading sparse list", ret);
 		goto fail;
+	}
 
 	if (ret < 512)
 		goto fail_format;
@@ -69,8 +71,11 @@ sparse_map_t *read_gnu_new_sparse(sqfs_istream_t *fp, tar_header_decoded_t *out)
 				goto fail_format;
 
 			ret = sqfs_istream_read(fp, buffer + 512, 512);
-			if (ret < 0)
+			if (ret < 0) {
+				sqfs_perror(fp->get_filename(fp),
+					    "reading sparse list", ret);
 				goto fail;
+			}
 
 			if (ret < 512)
 				goto fail_format;
diff --git a/lib/tar/src/read_sparse_map_old.c b/lib/tar/src/read_sparse_map_old.c
index 1794073..0915214 100644
--- a/lib/tar/src/read_sparse_map_old.c
+++ b/lib/tar/src/read_sparse_map_old.c
@@ -60,8 +60,11 @@ sparse_map_t *read_gnu_old_sparse(sqfs_istream_t *fp, tar_header_t *hdr)
 
 	do {
 		ret = sqfs_istream_read(fp, &sph, sizeof(sph));
-		if (ret < 0)
+		if (ret < 0) {
+			sqfs_perror(fp->get_filename(fp),
+				    "reading old GNU sparse list", ret);
 			goto fail;
+		}
 
 		if ((size_t)ret < sizeof(sph))
 			goto fail_eof;
diff --git a/lib/tar/src/record_to_memory.c b/lib/tar/src/record_to_memory.c
index 597d6f8..84beaa3 100644
--- a/lib/tar/src/record_to_memory.c
+++ b/lib/tar/src/record_to_memory.c
@@ -19,8 +19,10 @@ char *record_to_memory(sqfs_istream_t *fp, size_t size)
 		goto fail_errno;
 
 	ret = sqfs_istream_read(fp, buffer, size);
-	if (ret < 0)
+	if (ret < 0) {
+		sqfs_perror(fp->get_filename(fp), "reading tar record", ret);
 		goto fail;
+	}
 
 	if ((size_t)ret < size) {
 		fputs("Reading tar record: unexpected end-of-file.\n", stderr);
@@ -28,8 +30,12 @@ char *record_to_memory(sqfs_istream_t *fp, size_t size)
 	}
 
 	if (size % 512) {
-		if (sqfs_istream_skip(fp, 512 - (size % 512)))
+		ret = sqfs_istream_skip(fp, 512 - (size % 512));
+		if (ret) {
+			sqfs_perror(fp->get_filename(fp),
+				    "skipping tar padding", ret);
 			goto fail;
+		}
 	}
 
 	buffer[size] = '\0';
diff --git a/lib/tar/src/write_header.c b/lib/tar/src/write_header.c
index 1183c9a..dda98b7 100644
--- a/lib/tar/src/write_header.c
+++ b/lib/tar/src/write_header.c
@@ -8,6 +8,7 @@
 
 #include "internal.h"
 #include "sqfs/xattr.h"
+#include "sqfs/error.h"
 #include <string.h>
 #include <stdlib.h>
 
@@ -106,16 +107,19 @@ static int write_ext_header(sqfs_ostream_t *fp, const struct stat *orig,
 			    int type, const char *name)
 {
 	struct stat sb;
+	int ret;
 
 	sb = *orig;
 	sb.st_mode = S_IFREG | 0644;
 	sb.st_size = payload_len;
 
-	if (write_header(fp, &sb, name, NULL, type))
-		return -1;
+	ret = write_header(fp, &sb, name, NULL, type);
+	if (ret)
+		return ret;
 
-	if (fp->append(fp, payload, payload_len))
-		return -1;
+	ret = fp->append(fp, payload, payload_len);
+	if (ret)
+		return ret;
 
 	return padd_file(fp, payload_len);
 }
@@ -159,11 +163,8 @@ static int write_schily_xattr(sqfs_ostream_t *fp, const struct stat *orig,
 	}
 
 	buffer = calloc(1, total_size + 1);
-	if (buffer == NULL) {
-		fprintf(stderr, "%s: generating xattr header: "
-			"out-of-memory\n", name);
-		return -1;
-	}
+	if (buffer == NULL)
+		return SQFS_ERROR_ALLOC;
 
 	ptr = buffer;
 
@@ -188,15 +189,15 @@ int write_tar_header(sqfs_ostream_t *fp,
 		     const char *slink_target, const sqfs_xattr_t *xattr,
 		     unsigned int counter)
 {
-	const char *reason;
 	char buffer[64];
-	int type;
+	int type, ret;
 
 	if (xattr != NULL) {
 		sprintf(buffer, "pax/xattr%u", counter);
 
-		if (write_schily_xattr(fp, sb, buffer, xattr))
-			return -1;
+		ret = write_schily_xattr(fp, sb, buffer, xattr);
+		if (ret)
+			return ret;
 	}
 
 	if (!S_ISLNK(sb->st_mode))
@@ -204,19 +205,20 @@ int write_tar_header(sqfs_ostream_t *fp,
 
 	if (S_ISLNK(sb->st_mode) && sb->st_size >= 100) {
 		sprintf(buffer, "gnu/target%u", counter);
-		if (write_ext_header(fp, sb, slink_target, sb->st_size,
-				     TAR_TYPE_GNU_SLINK, buffer))
-			return -1;
+		ret = write_ext_header(fp, sb, slink_target, sb->st_size,
+				       TAR_TYPE_GNU_SLINK, buffer);
+		if (ret)
+			return ret;
 		slink_target = NULL;
 	}
 
 	if (strlen(name) >= 100) {
 		sprintf(buffer, "gnu/name%u", counter);
 
-		if (write_ext_header(fp, sb, name, strlen(name),
-				     TAR_TYPE_GNU_PATH, buffer)) {
-			return -1;
-		}
+		ret = write_ext_header(fp, sb, name, strlen(name),
+				       TAR_TYPE_GNU_PATH, buffer);
+		if (ret)
+			return ret;
 
 		sprintf(buffer, "gnu/data%u", counter);
 		name = buffer;
@@ -229,18 +231,11 @@ int write_tar_header(sqfs_ostream_t *fp,
 	case S_IFREG: type = TAR_TYPE_FILE; break;
 	case S_IFDIR: type = TAR_TYPE_DIR; break;
 	case S_IFIFO: type = TAR_TYPE_FIFO; break;
-	case S_IFSOCK:
-		reason = "cannot pack socket";
-		goto out_skip;
 	default:
-		reason = "unknown type";
-		goto out_skip;
+		return SQFS_ERROR_UNSUPPORTED;
 	}
 
 	return write_header(fp, sb, name, slink_target, type);
-out_skip:
-	fprintf(stderr, "WARNING: %s: %s\n", name, reason);
-	return 1;
 }
 
 int write_hard_link(sqfs_ostream_t *fp, const struct stat *sb, const char *name,
@@ -249,15 +244,17 @@ int write_hard_link(sqfs_ostream_t *fp, const struct stat *sb, const char *name,
 	tar_header_t hdr;
 	char buffer[64];
 	size_t len;
+	int ret;
 
 	memset(&hdr, 0, sizeof(hdr));
 
 	len = strlen(target);
 	if (len >= 100) {
 		sprintf(buffer, "gnu/target%u", counter);
-		if (write_ext_header(fp, sb, target, len,
-				     TAR_TYPE_GNU_SLINK, buffer))
-			return -1;
+		ret = write_ext_header(fp, sb, target, len,
+				       TAR_TYPE_GNU_SLINK, buffer);
+		if (ret)
+			return ret;
 		sprintf(hdr.linkname, "hardlink_%u", counter);
 	} else {
 		memcpy(hdr.linkname, target, len);
@@ -266,10 +263,10 @@ int write_hard_link(sqfs_ostream_t *fp, const struct stat *sb, const char *name,
 	len = strlen(name);
 	if (len >= 100) {
 		sprintf(buffer, "gnu/name%u", counter);
-		if (write_ext_header(fp, sb, name, len,
-				     TAR_TYPE_GNU_PATH, buffer)) {
-			return -1;
-		}
+		ret = write_ext_header(fp, sb, name, len,
+				       TAR_TYPE_GNU_PATH, buffer);
+		if (ret)
+			return ret;
 		sprintf(hdr.name, "gnu/data%u", counter);
 	} else {
 		memcpy(hdr.name, name, len);
diff --git a/lib/tar/test/tar_big_file.c b/lib/tar/test/tar_big_file.c
index 444548b..6a88d4c 100644
--- a/lib/tar/test/tar_big_file.c
+++ b/lib/tar/test/tar_big_file.c
@@ -13,9 +13,11 @@ int main(int argc, char **argv)
 {
 	tar_header_decoded_t hdr;
 	sqfs_istream_t *fp;
+	int ret;
 	(void)argc; (void)argv;
 
-	fp = istream_open_file(STRVALUE(TESTPATH) "/" STRVALUE(TESTFILE));
+	ret = istream_open_file(&fp, STRVALUE(TESTPATH) "/" STRVALUE(TESTFILE));
+	TEST_EQUAL_I(ret, 0);
 	TEST_NOT_NULL(fp);
 	TEST_ASSERT(read_header(fp, &hdr) == 0);
 	TEST_EQUAL_UI(hdr.mode, S_IFREG | 0644);
diff --git a/lib/tar/test/tar_fuzz.c b/lib/tar/test/tar_fuzz.c
index 92c0952..42fe73d 100644
--- a/lib/tar/test/tar_fuzz.c
+++ b/lib/tar/test/tar_fuzz.c
@@ -8,6 +8,7 @@
 
 #include "io/file.h"
 #include "tar/tar.h"
+#include "common.h"
 
 #include <stdlib.h>
 #include <stdio.h>
@@ -23,9 +24,11 @@ int main(int argc, char **argv)
 		return EXIT_FAILURE;
 	}
 
-	fp = istream_open_file(argv[1]);
-	if (fp == NULL)
+	ret = istream_open_file(&fp, argv[1]);
+	if (ret) {
+		sqfs_perror("stdint", NULL, ret);
 		return EXIT_FAILURE;
+	}
 
 	for (;;) {
 		ret = read_header(fp, &hdr);
diff --git a/lib/tar/test/tar_iterator.c b/lib/tar/test/tar_iterator.c
index f51ecd6..8de50ed 100644
--- a/lib/tar/test/tar_iterator.c
+++ b/lib/tar/test/tar_iterator.c
@@ -36,10 +36,13 @@ int main(int argc, char **argv)
 	char buffer[100];
 	sqfs_s32 ret;
 	sqfs_s64 ts;
+	int iret;
 	(void)argc; (void)argv;
 
 	/* Open the file, create an iterator */
-	fp = istream_open_file(STRVALUE(TESTPATH) "/" STRVALUE(TESTFILE));
+	iret = istream_open_file(&fp,
+				 STRVALUE(TESTPATH) "/" STRVALUE(TESTFILE));
+	TEST_EQUAL_I(iret, 0);
 	TEST_NOT_NULL(fp);
 	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
 	it = tar_open_stream(fp);
@@ -106,7 +109,9 @@ int main(int argc, char **argv)
 	sqfs_drop(fp);
 
 	/* re-open the tar iterator */
-	fp = istream_open_file(STRVALUE(TESTPATH) "/" STRVALUE(TESTFILE));
+	iret = istream_open_file(&fp,
+				 STRVALUE(TESTPATH) "/" STRVALUE(TESTFILE));
+	TEST_EQUAL_I(iret, 0);
 	TEST_NOT_NULL(fp);
 	it = tar_open_stream(fp);
 	TEST_NOT_NULL(it);
diff --git a/lib/tar/test/tar_iterator2.c b/lib/tar/test/tar_iterator2.c
index 7483e81..8826762 100644
--- a/lib/tar/test/tar_iterator2.c
+++ b/lib/tar/test/tar_iterator2.c
@@ -49,9 +49,12 @@ int main(int argc, char **argv)
 	dir_entry_t *ent;
 	uint64_t offset;
 	sqfs_s32 i, ret;
+	int iret;
 	(void)argc; (void)argv;
 
-	fp = istream_open_file(STRVALUE(TESTPATH) "/" STRVALUE(TESTFILE));
+	iret = istream_open_file(&fp,
+				 STRVALUE(TESTPATH) "/" STRVALUE(TESTFILE));
+	TEST_EQUAL_I(iret, 0);
 	TEST_NOT_NULL(fp);
 	it = tar_open_stream(fp);
 	TEST_NOT_NULL(it);
diff --git a/lib/tar/test/tar_iterator3.c b/lib/tar/test/tar_iterator3.c
index 11c2fd2..0aee0e3 100644
--- a/lib/tar/test/tar_iterator3.c
+++ b/lib/tar/test/tar_iterator3.c
@@ -23,7 +23,8 @@ int main(int argc, char **argv)
 
 	TEST_ASSERT(chdir(TEST_PATH) == 0);
 
-	fp = istream_open_file("format-acceptance/link_filled.tar");
+	ret = istream_open_file(&fp, "format-acceptance/link_filled.tar");
+	TEST_EQUAL_I(ret, 0);
 	TEST_NOT_NULL(fp);
 	TEST_EQUAL_UI(((sqfs_object_t *)fp)->refcount, 1);
 	it = tar_open_stream(fp);
diff --git a/lib/tar/test/tar_simple.c b/lib/tar/test/tar_simple.c
index a666eb5..8ee5b84 100644
--- a/lib/tar/test/tar_simple.c
+++ b/lib/tar/test/tar_simple.c
@@ -40,9 +40,11 @@ int main(int argc, char **argv)
 	sqfs_istream_t *fp;
 	char buffer[6];
 	sqfs_s64 ts;
+	int ret;
 	(void)argc; (void)argv;
 
-	fp = istream_open_file(STRVALUE(TESTPATH) "/" STRVALUE(TESTFILE));
+	ret = istream_open_file(&fp, STRVALUE(TESTPATH) "/" STRVALUE(TESTFILE));
+	TEST_EQUAL_I(ret, 0);
 	TEST_NOT_NULL(fp);
 	TEST_ASSERT(read_header(fp, &hdr) == 0);
 	TEST_EQUAL_UI(hdr.mode, S_IFREG | 0644);
diff --git a/lib/tar/test/tar_sparse.c b/lib/tar/test/tar_sparse.c
index 99d4639..d93482d 100644
--- a/lib/tar/test/tar_sparse.c
+++ b/lib/tar/test/tar_sparse.c
@@ -14,8 +14,10 @@ static void test_case_sparse(const char *path)
 	tar_header_decoded_t hdr;
 	sparse_map_t *sparse;
 	sqfs_istream_t *fp;
+	int ret;
 
-	fp = istream_open_file(path);
+	ret = istream_open_file(&fp, path);
+	TEST_EQUAL_I(ret, 0);
 	TEST_NOT_NULL(fp);
 	TEST_ASSERT(read_header(fp, &hdr) == 0);
 	TEST_EQUAL_UI(hdr.mode, S_IFREG | 0644);
diff --git a/lib/tar/test/tar_sparse_gnu.c b/lib/tar/test/tar_sparse_gnu.c
index 675ef9a..6effb52 100644
--- a/lib/tar/test/tar_sparse_gnu.c
+++ b/lib/tar/test/tar_sparse_gnu.c
@@ -14,11 +14,13 @@ int main(int argc, char **argv)
 	tar_header_decoded_t hdr;
 	sparse_map_t *sparse;
 	sqfs_istream_t *fp;
+	int ret;
 	(void)argc; (void)argv;
 
 	TEST_ASSERT(chdir(TEST_PATH) == 0);
 
-	fp = istream_open_file("sparse-files/gnu-small.tar");
+	ret = istream_open_file(&fp, "sparse-files/gnu-small.tar");
+	TEST_EQUAL_I(ret, 0);
 	TEST_NOT_NULL(fp);
 	TEST_ASSERT(read_header(fp, &hdr) == 0);
 	TEST_EQUAL_UI(hdr.mode, S_IFREG | 0644);
diff --git a/lib/tar/test/tar_target_filled.c b/lib/tar/test/tar_target_filled.c
index 4f061c0..85a1af4 100644
--- a/lib/tar/test/tar_target_filled.c
+++ b/lib/tar/test/tar_target_filled.c
@@ -14,11 +14,13 @@ int main(int argc, char **argv)
 	tar_header_decoded_t hdr;
 	sqfs_istream_t *fp;
 	char buffer[16];
+	int ret;
 	(void)argc; (void)argv;
 
 	TEST_ASSERT(chdir(TEST_PATH) == 0);
 
-	fp = istream_open_file("format-acceptance/link_filled.tar");
+	ret = istream_open_file(&fp, "format-acceptance/link_filled.tar");
+	TEST_EQUAL_I(ret, 0);
 	TEST_NOT_NULL(fp);
 
 	/* "deep" directory hierarchy containg 2 files */
diff --git a/lib/tar/test/tar_write_simple.c b/lib/tar/test/tar_write_simple.c
index ca8d1e5..28f199f 100644
--- a/lib/tar/test/tar_write_simple.c
+++ b/lib/tar/test/tar_write_simple.c
@@ -188,7 +188,8 @@ int main(int argc, char **argv)
 	TEST_EQUAL_UI(wr_offset, sizeof(wr_buffer));
 	TEST_EQUAL_UI(sizeof(rd_buffer), sizeof(wr_buffer));
 
-	fp = istream_open_file(STRVALUE(TESTPATH) "/" STRVALUE(TESTFILE));
+	ret = istream_open_file(&fp, STRVALUE(TESTPATH) "/" STRVALUE(TESTFILE));
+	TEST_EQUAL_I(ret, 0);
 	TEST_NOT_NULL(fp);
 
 	ret = sqfs_istream_read(fp, rd_buffer, sizeof(rd_buffer));
diff --git a/lib/tar/test/tar_xattr.c b/lib/tar/test/tar_xattr.c
index 26a2cd0..0e0579c 100644
--- a/lib/tar/test/tar_xattr.c
+++ b/lib/tar/test/tar_xattr.c
@@ -15,9 +15,11 @@ int main(int argc, char **argv)
 	tar_header_decoded_t hdr;
 	sqfs_istream_t *fp;
 	char buffer[6];
+	int ret;
 	(void)argc; (void)argv;
 
-	fp = istream_open_file(STRVALUE(TESTPATH) "/" STRVALUE(TESTFILE));
+	ret = istream_open_file(&fp, STRVALUE(TESTPATH) "/" STRVALUE(TESTFILE));
+	TEST_EQUAL_I(ret, 0);
 	TEST_NOT_NULL(fp);
 	TEST_ASSERT(read_header(fp, &hdr) == 0);
 	TEST_EQUAL_UI(hdr.mode, S_IFREG | 0644);
diff --git a/lib/tar/test/tar_xattr_bin.c b/lib/tar/test/tar_xattr_bin.c
index 94c8d76..617c356 100644
--- a/lib/tar/test/tar_xattr_bin.c
+++ b/lib/tar/test/tar_xattr_bin.c
@@ -23,9 +23,11 @@ int main(int argc, char **argv)
 	tar_header_decoded_t hdr;
 	sqfs_istream_t *fp;
 	char buffer[6];
+	int ret;
 	(void)argc; (void)argv;
 
-	fp = istream_open_file(STRVALUE(TESTPATH) "/" STRVALUE(TESTFILE));
+	ret = istream_open_file(&fp, STRVALUE(TESTPATH) "/" STRVALUE(TESTFILE));
+	TEST_EQUAL_I(ret, 0);
 	TEST_NOT_NULL(fp);
 	TEST_ASSERT(read_header(fp, &hdr) == 0);
 	TEST_EQUAL_UI(hdr.mode, S_IFREG | 0644);
diff --git a/lib/util/test/str_table.c b/lib/util/test/str_table.c
index 75658ef..4a62b59 100644
--- a/lib/util/test/str_table.c
+++ b/lib/util/test/str_table.c
@@ -21,7 +21,8 @@ static int read_strings(void)
 	char *line;
 	int i;
 
-	fp = istream_open_file("words.txt");
+	i = istream_open_file(&fp, "words.txt");
+	TEST_EQUAL_I(i, 0);
 	TEST_NOT_NULL(fp);
 
 	for (i = 0; i < 1000; ++i) {