[PATCH] fix a Gcc undefined behavior Upstream-Status: Pending Calling strncpy with NULL second argument, even when the size is 0, is undefined behavior, which leads to GCC to drop the check old variable with NULL in following code. https://bugzilla.yoctoproject.org/show_bug.cgi?id=6743 Signed-off-by: Roy Li --- support/export/client.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/support/export/client.c b/support/export/client.c index dbf47b9..a37ef69 100644 --- a/support/export/client.c +++ b/support/export/client.c @@ -482,8 +482,13 @@ add_name(char *old, const char *add) else cp = cp + strlen(cp); } - strncpy(new, old, cp-old); - new[cp-old] = 0; + + if (old) { + strncpy(new, old, cp-old); + new[cp-old] = 0; + } else + new[0] = 0; + if (cp != old && !*cp) strcat(new, ","); strcat(new, add); -- 1.7.10.4