From: Patrick Steinhardt Date: Sun, 22 Dec 2024 07:24:31 +0000 (+0100) Subject: reftable/basics: return NULL on zero-sized allocations X-Git-Tag: v2.48.0-rc1~23^2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d7282891f542b58410a209230009182b9057af79;p=thirdparty%2Fgit.git reftable/basics: return NULL on zero-sized allocations In the preceding commits we have fixed a couple of issues when allocating zero-sized objects. These issues were masked by implementation-defined behaviour. Quoting malloc(3p): If size is 0, either: * A null pointer shall be returned and errno may be set to an implementation-defined value, or * A pointer to the allocated space shall be returned. The application shall ensure that the pointer is not used to access an object. So it is perfectly valid that implementations of this function may or may not return a NULL pointer in such a case. Adapt both `reftable_malloc()` and `reftable_realloc()` so that they return NULL pointers on zero-sized allocations. This should remove any implementation-defined behaviour in our allocators and thus allows us to detect such platform-specific issues more easily going forward. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano --- diff --git a/reftable/basics.c b/reftable/basics.c index 9a949e5cf8..eab5553d93 100644 --- a/reftable/basics.c +++ b/reftable/basics.c @@ -16,6 +16,8 @@ static void (*reftable_free_ptr)(void *); void *reftable_malloc(size_t sz) { + if (!sz) + return NULL; if (reftable_malloc_ptr) return (*reftable_malloc_ptr)(sz); return malloc(sz); @@ -23,6 +25,11 @@ void *reftable_malloc(size_t sz) void *reftable_realloc(void *p, size_t sz) { + if (!sz) { + reftable_free(p); + return NULL; + } + if (reftable_realloc_ptr) return (*reftable_realloc_ptr)(p, sz); return realloc(p, sz);