[systemd-devel] [PATCH] journal: fix assert against (theoretical) undefined behavior

[Shawn Landden]

While all the libc implementations I know return NULL when memchr's size
parameter is 0:

C11 7.24.1p2: Where an argument declared as "size_t n" specifies the length
of the array for a function, n can have the value zero on a call to that
function. Unless explicitly stated otherwise in the description of a
particular function in this subclause, pointer arguments on such a call
shall still have valid values, as described in 7.1.4. On such a call, a
function that locates a character finds no occurrence, a function that
compares two character sequences returns zero, and a function that copies
characters copies zero characters.

see http://llvm.org/bugs/show_bug.cgi?id=18247
---
 src/journal/journal-file.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/journal/journal-file.c b/src/journal/journal-file.c
index 4009b29..59b2829 100644
--- a/src/journal/journal-file.c
+++ b/src/journal/journal-file.c
@@ -956,7 +956,7 @@ static int journal_file_append_data(
         const void *eq;
 
         assert(f);
-        assert(data || size == 0);
+        assert(data);
 
         hash = hash64(data, size);
 
-- 
1.8.5.1