Do not use dlopen() for zero-size libraries on FreeBSD and DragonFlyBSD

See for more info: https://reviews.freebsd.org/D5112

Author: saprykin

src/plibraryloader.c

@@ -25,6 +25,15 @@
 #  include <dlfcn.h>
 #endif
 
+/* FreeBSD may cause a segfault: https://reviews.freebsd.org/D5112,
+ * DragonFlyBSD as well, so we need to check a file size before calling dlopen()
+ */
+#if defined (P_OS_FREEBSD) || defined (P_OS_DRAGONFLY)
+#  include <unistd.h>
+#  include <sys/types.h>
+#  include <sys/stat.h>
+#endif
+
 #ifdef P_OS_WIN
 	typedef HINSTANCE	plibrary_handle;
 #else
@@ -54,12 +63,27 @@ p_library_loader_new (const pchar *path)
 {
 	PLibraryLoader	*loader;
 	plibrary_handle	handle;
+#if defined (P_OS_FREEBSD) || defined (P_OS_DRAGONFLY)
+	struct stat	stat_buf;
+#endif
 
 	loader = NULL;
 
 	if (!p_file_is_exists (path))
 		return NULL;
 
+#if defined (P_OS_FREEBSD) || defined (P_OS_DRAGONFLY)
+	if (P_UNLIKELY (stat (path, &stat_buf) != 0)) {
+		P_ERROR ("PLibraryLoader: failed to call stat()");
+		return NULL;
+	}
+
+	if (P_UNLIKELY (stat_buf.st_size == 0)) {
+		P_ERROR ("PLibraryLoader: unable to handle zero-size file");
+		return NULL;
+	}
+#endif
+
 #ifdef P_OS_WIN
 	if (P_UNLIKELY ((handle = LoadLibraryA (path)) == NULL)) {
 		P_ERROR ("PLibraryLoader: failed to call LoadLibraryA()");

tests/plibraryloader_test.cpp

@@ -79,10 +79,7 @@ BOOST_AUTO_TEST_CASE (plibraryloader_nomem_test)
 
 	int argCount = boost::unit_test::framework::master_test_suite().argc;
 
-	/* FreeBSD may cause a segfault :https://reviews.freebsd.org/D5112 */
-#ifndef P_OS_FREEBSD
 	BOOST_CHECK (p_library_loader_new ("." P_DIR_SEPARATOR "p_empty_file.txt") == NULL);
-#endif
 	BOOST_CHECK (p_library_loader_new (boost::unit_test::framework::master_test_suite().argv[argCount - 1]) == NULL);
 
 #ifdef P_OS_WIN