libmount: use vsnprintf() in more robust way [coverity scan]

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/libmount/src/context.c b/libmount/src/context.c
index a6944ffe5116da998cf369b9d24aed2c96e03b66..6c536cc1552f4c4a735b4b8782ed058ab8060d10 100644 (file)
--- a/libmount/src/context.c
+++ b/libmount/src/context.c
@@ -2684,8 +2684,8 @@ int mnt_context_get_generic_excode(int rc, char *buf, size_t bufsz, char *fmt, .
        /* we need to support "%m" */
        errno = rc < 0 ? -rc : rc;
 
-       if (buf)
-               vsnprintf(buf, bufsz, fmt, va);
+       if (buf && bufsz && vsnprintf(buf, bufsz, fmt, va) < 0)
+               *buf = '\0';
 
        switch (errno) {
        case EINVAL: