Add a snprinf wrapper which checks that the buffer was big enough

If we scale our buffer to be wide enough for the format string, we
should expect that the calculation was correct.

char_array_0() invocations are removed, since snprintf nul-terminates
the output in any case.

A similar wrapper is used for strftime calls, but only in timedatectl.c.

1 files changed, 1 insertions, 2 deletions

diff --git a/src/journal/sd-journal.c b/src/journal/sd-journal.c
index 9bc426faf8..9dea5470be 100644
--- a/src/journal/sd-journal.c
+++ b/src/journal/sd-journal.c
@@ -1178,8 +1178,7 @@ static bool file_type_wanted(int flags, const char *filename) {
         if (flags & SD_JOURNAL_CURRENT_USER) {
                 char prefix[5 + DECIMAL_STR_MAX(uid_t) + 1];
 
-                assert_se(snprintf(prefix, sizeof(prefix), "user-"UID_FMT, getuid())
-                          < (int) sizeof(prefix));
+                xsprintf(prefix, "user-"UID_FMT, getuid());
 
                 if (file_has_type_prefix(prefix, filename))
                         return true;