From 706fb34851be3116e28d6abd2c879f984c3d8c83 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= Date: Wed, 10 Jul 2019 10:22:48 +0200 Subject: [PATCH] shared/dm-util: use strncpy_exact() to silence gcc MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit With gcc-9.1.1-2.fc31.x86_64 and -Doptimization=2: ../src/shared/dm-util.c: In function ‘dm_deferred_remove’: ../src/shared/dm-util.c:35:9: warning: ‘strncpy’ specified bound 128 equals destination size [-Wstringop-truncation] 35 | strncpy(dm.name, name, sizeof(dm.name)); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ gcc is plain wrong here, because we checked strlen(name) a few lines above, so there can be no truncation and even the terminator always fits. But let's avoid the warning. --- src/shared/dm-util.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/src/shared/dm-util.c b/src/shared/dm-util.c index a17b85b64ad..f73bf93520a 100644 --- a/src/shared/dm-util.c +++ b/src/shared/dm-util.c @@ -5,6 +5,7 @@ #include "dm-util.h" #include "fd-util.h" +#include "string-util.h" int dm_deferred_remove(const char *name) { @@ -25,14 +26,14 @@ int dm_deferred_remove(const char *name) { /* Unfortunately, libcryptsetup doesn't provide a proper API for this, hence call the ioctl() * directly. */ - if (strlen(name) > sizeof(dm.name)-1) + if (strlen(name) >= sizeof(dm.name)) return -ENODEV; /* A device with a name longer than this cannot possibly exist */ fd = open("/dev/mapper/control", O_RDWR|O_CLOEXEC); if (fd < 0) return -errno; - strncpy(dm.name, name, sizeof(dm.name)); + strncpy_exact(dm.name, name, sizeof(dm.name)); if (ioctl(fd, DM_DEV_REMOVE, &dm)) return -errno;