Fix: libsquashfs: add sqfs_free() function

On systems like Windows, the dynamic library and applications can
easily end up being linked against different runtime libraries, so
applications cannot be expected to be able to free() any malloc'd
pointer that the library returns.

This commit adds an sqfs_free function so the application can pass
pointers back to the library to call the correct free() implementation.

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

2 files changed, 18 insertions, 0 deletions

diff --git a/lib/sqfs/Makemodule.am b/lib/sqfs/Makemodule.am
index d6b392e..df6e3ce 100644
--- a/lib/sqfs/Makemodule.am
+++ b/lib/sqfs/Makemodule.am
@@ -30,6 +30,7 @@ libsquashfs_la_SOURCES += lib/sqfs/block_processor/block_processor.c
 libsquashfs_la_SOURCES += lib/sqfs/block_processor/backend.c
 libsquashfs_la_SOURCES += lib/sqfs/frag_table.c include/sqfs/frag_table.h
 libsquashfs_la_SOURCES += lib/sqfs/block_writer.c include/sqfs/block_writer.h
+libsquashfs_la_SOURCES += lib/sqfs/misc.c
 libsquashfs_la_CPPFLAGS = $(AM_CPPFLAGS)
 libsquashfs_la_LDFLAGS = $(AM_LDFLAGS) -version-info $(LIBSQUASHFS_SO_VERSION)
 libsquashfs_la_CFLAGS = $(AM_CFLAGS) $(PTHREAD_CFLAGS) $(ZLIB_CFLAGS)
diff --git a/lib/sqfs/misc.c b/lib/sqfs/misc.c
new file mode 100644
index 0000000..74a4203
--- /dev/null
+++ b/lib/sqfs/misc.c
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: LGPL-3.0-or-later */
+/*
+ * misc.c
+ *
+ * Copyright (C) 2021 David Oberhollenzer <goliath@infraroot.at>
+ */
+#define SQFS_BUILDING_DLL
+#include "config.h"
+
+#include "sqfs/predef.h"
+
+#include <stdlib.h>
+
+void sqfs_free(void *ptr)
+{
+	free(ptr);
+}