Merge pull request #20346 from poettering/strlen-unsigned-fix

CONST_MAX() integer size fix

src/basic/macro.h

@@ -214,7 +214,7 @@ static inline size_t GREEDY_ALLOC_ROUND_UP(size_t l) {
  *          Contrary to strlen(), this is a constant expression.
  * @x: a string literal.
  */
-#define STRLEN(x) ((unsigned) sizeof(""x"") - 1)
+#define STRLEN(x) (sizeof(""x"") - 1U)
 
 /*
  * container_of - cast a member of a structure out to the containing structure
@@ -345,12 +345,12 @@ static inline int __coverity_check_and_return__(int condition) {
         (2U+(sizeof(type) <= 1 ? 3U :                                   \
              sizeof(type) <= 2 ? 5U :                                   \
              sizeof(type) <= 4 ? 10U :                                  \
-             sizeof(type) <= 8 ? 20U : (unsigned) sizeof(int[-2*(sizeof(type) > 8)])))
+             sizeof(type) <= 8 ? 20U : sizeof(int[-2*(sizeof(type) > 8)])))
 
 #define DECIMAL_STR_WIDTH(x)                            \
         ({                                              \
                 typeof(x) _x_ = (x);                    \
-                unsigned ans = 1;                       \
+                size_t ans = 1;                         \
                 while ((_x_ /= 10) != 0)                \
                         ans++;                          \
                 ans;                                    \

src/fundamental/macro-fundamental.h

@@ -70,12 +70,29 @@
                 UNIQ_T(A, aq) > UNIQ_T(B, bq) ? UNIQ_T(A, aq) : UNIQ_T(B, bq); \
         })
 
-/* evaluates to (void) if _A or _B are not constant or of different types */
+#define IS_UNSIGNED_INTEGER_TYPE(type) \
+        (__builtin_types_compatible_p(typeof(type), unsigned char) ||   \
+         __builtin_types_compatible_p(typeof(type), unsigned short) ||  \
+         __builtin_types_compatible_p(typeof(type), unsigned) ||        \
+         __builtin_types_compatible_p(typeof(type), unsigned long) ||   \
+         __builtin_types_compatible_p(typeof(type), unsigned long long))
+
+#define IS_SIGNED_INTEGER_TYPE(type) \
+        (__builtin_types_compatible_p(typeof(type), signed char) ||   \
+         __builtin_types_compatible_p(typeof(type), signed short) ||  \
+         __builtin_types_compatible_p(typeof(type), signed) ||        \
+         __builtin_types_compatible_p(typeof(type), signed long) ||   \
+         __builtin_types_compatible_p(typeof(type), signed long long))
+
+/* Evaluates to (void) if _A or _B are not constant or of different types (being integers of different sizes
+ * is also OK as long as the signedness matches) */
 #define CONST_MAX(_A, _B) \
         (__builtin_choose_expr(                                         \
                 __builtin_constant_p(_A) &&                             \
                 __builtin_constant_p(_B) &&                             \
-                __builtin_types_compatible_p(typeof(_A), typeof(_B)),   \
+                (__builtin_types_compatible_p(typeof(_A), typeof(_B)) || \
+                 (IS_UNSIGNED_INTEGER_TYPE(_A) && IS_UNSIGNED_INTEGER_TYPE(_B)) || \
+                 (IS_SIGNED_INTEGER_TYPE(_A) && IS_SIGNED_INTEGER_TYPE(_B))), \
                 ((_A) > (_B)) ? (_A) : (_B),                            \
                 VOID_0))