[BlueZ 2/5] shared/util: Add helper for "cleanup" variable attribute

[Bastien Nocera <hadess@hadess.net>]

Use the widespread "cleanup" variable attribute:
https://gcc.gnu.org/onlinedocs/gcc/Common-Attributes.html#index-cleanup

It is implemented by both GCC and clang on platforms where bluez is
used, and can help reduce memory leaks, while improving readability.

See also:
https://systemd.io/CODING_STYLE/#memory-allocation
https://docs.gtk.org/glib/auto-cleanup.html
---
 src/shared/util.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/shared/util.h b/src/shared/util.h
index 67629dddfaa9..90e3b32f86fe 100644
--- a/src/shared/util.h
+++ b/src/shared/util.h
@@ -93,6 +93,13 @@ do {						\
 #define newa(t, n) ((t*) alloca(sizeof(t)*(n)))
 #define malloc0(n) (calloc(1, (n)))
 
+static inline void freep(void *p) {
+        free(*(void**) p);
+}
+
+#define _cleanup_(f) __attribute__((cleanup(f)))
+#define _cleanup_free_ _cleanup_(freep)
+
 char *strdelimit(char *str, char *del, char c);
 int strsuffix(const char *str, const char *suffix);
 char *strstrip(char *str);
-- 
2.54.0