Merge pull request #20499 from poettering/align-to-tweak

ALIGN_TO() tweaks

src/basic/macro.h

@@ -146,6 +146,20 @@
 #define ALIGN8_PTR(p) ((void*) ALIGN8((unsigned long) (p)))
 
 static inline size_t ALIGN_TO(size_t l, size_t ali) {
+        /* Check that alignment is exponent of 2 */
+#if SIZE_MAX == UINT_MAX
+        assert(__builtin_popcount(ali) == 1);
+#elif SIZE_MAX == ULONG_MAX
+        assert(__builtin_popcountl(ali) == 1);
+#elif SIZE_MAX == ULONGLONG_MAX
+        assert(__builtin_popcountll(ali) == 1);
+#else
+#error "Unexpected size_t"
+#endif
+
+        if (l > SIZE_MAX - (ali - 1))
+                return SIZE_MAX; /* indicate overflow */
+
         return ((l + ali - 1) & ~(ali - 1));
 }