[PATCH 6/8] treewide: Address cert-err33-c clang-tidy warnings for clock and timer functions

[Stefano Brivio <sbrivio@redhat.com>]

For clock_gettime(), we shouldn't ignore errors if they happen at
initialisation phase, because something is seriously wrong and it's
not helpful if we proceed as if nothing happened.

As we're up and running, though, it's probably better to use a stale
value than to terminate altogether. Make sure we use a zero value if
we don't have a stale one somewhere.

For timerfd_gettime() and timerfd_settime() failures, report an error,
there isn't much else we can do.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
---
 passt.c |  8 +++++---
 pcap.c  | 12 ++++++------
 tcp.c   | 12 +++++++++---
 3 files changed, 20 insertions(+), 12 deletions(-)

diff --git a/passt.c b/passt.c
index ad6f0bc..e987f0d 100644
--- a/passt.c
+++ b/passt.c
@@ -207,7 +207,8 @@ int main(int argc, char **argv)
 	struct timespec now;
 	struct sigaction sa;
 
-	clock_gettime(CLOCK_MONOTONIC, &log_start);
+	if (clock_gettime(CLOCK_MONOTONIC, &log_start))
+		die_perror("Failed to get CLOCK_MONOTONIC time");
 
 	arch_avx2_exec(argv);
 
@@ -265,7 +266,8 @@ int main(int argc, char **argv)
 
 	secret_init(&c);
 
-	clock_gettime(CLOCK_MONOTONIC, &now);
+	if (clock_gettime(CLOCK_MONOTONIC, &now))
+		die_perror("Failed to get CLOCK_MONOTONIC time");
 
 	flow_init();
 
@@ -313,7 +315,7 @@ loop:
 	if (nfds == -1 && errno != EINTR)
 		die_perror("epoll_wait() failed in main loop");
 
-	clock_gettime(CLOCK_MONOTONIC, &now);
+	(void)clock_gettime(CLOCK_MONOTONIC, &now);
 
 	for (i = 0; i < nfds; i++) {
 		union epoll_ref ref = *((union epoll_ref *)&events[i].data.u64);
diff --git a/pcap.c b/pcap.c
index 6753cfb..156c953 100644
--- a/pcap.c
+++ b/pcap.c
@@ -100,12 +100,12 @@ static void pcap_frame(const struct iovec *iov, size_t iovcnt,
 void pcap(const char *pkt, size_t l2len)
 {
 	struct iovec iov = { (char *)pkt, l2len };
-	struct timespec now;
+	struct timespec now = { 0 };
 
 	if (pcap_fd == -1)
 		return;
 
-	clock_gettime(CLOCK_REALTIME, &now);
+	(void)clock_gettime(CLOCK_REALTIME, &now);
 	pcap_frame(&iov, 1, 0, &now);
 }
 
@@ -119,13 +119,13 @@ void pcap(const char *pkt, size_t l2len)
 void pcap_multiple(const struct iovec *iov, size_t frame_parts, unsigned int n,
 		   size_t offset)
 {
-	struct timespec now;
+	struct timespec now = { 0 };
 	unsigned int i;
 
 	if (pcap_fd == -1)
 		return;
 
-	clock_gettime(CLOCK_REALTIME, &now);
+	(void)clock_gettime(CLOCK_REALTIME, &now);
 
 	for (i = 0; i < n; i++)
 		pcap_frame(iov + i * frame_parts, frame_parts, offset, &now);
@@ -143,12 +143,12 @@ void pcap_multiple(const struct iovec *iov, size_t frame_parts, unsigned int n,
 /* cppcheck-suppress unusedFunction */
 void pcap_iov(const struct iovec *iov, size_t iovcnt, size_t offset)
 {
-	struct timespec now;
+	struct timespec now = { 0 };
 
 	if (pcap_fd == -1)
 		return;
 
-	clock_gettime(CLOCK_REALTIME, &now);
+	(void)clock_gettime(CLOCK_REALTIME, &now);
 	pcap_frame(iov, iovcnt, offset, &now);
 }
 
diff --git a/tcp.c b/tcp.c
index 0d22e07..d55caee 100644
--- a/tcp.c
+++ b/tcp.c
@@ -548,7 +548,8 @@ static void tcp_timer_ctl(const struct ctx *c, struct tcp_tap_conn *conn)
 		 (unsigned long long)it.it_value.tv_sec,
 		 (unsigned long long)it.it_value.tv_nsec / 1000 / 1000);
 
-	timerfd_settime(conn->timer, 0, &it, NULL);
+	if (timerfd_settime(conn->timer, 0, &it, NULL))
+		flow_err(conn, "failed to set timer: %s", strerror(errno));
 }
 
 /**
@@ -2240,7 +2241,9 @@ void tcp_timer_handler(const struct ctx *c, union epoll_ref ref)
 	 * timer is currently armed, this event came from a previous setting,
 	 * and we just set the timer to a new point in the future: discard it.
 	 */
-	timerfd_gettime(conn->timer, &check_armed);
+	if (timerfd_gettime(conn->timer, &check_armed))
+		flow_err(conn, "failed to read timer: %s", strerror(errno));
+
 	if (check_armed.it_value.tv_sec || check_armed.it_value.tv_nsec)
 		return;
 
@@ -2278,7 +2281,10 @@ void tcp_timer_handler(const struct ctx *c, union epoll_ref ref)
 		 * case. This avoids having to preemptively reset the timer on
 		 * ~ACK_TO_TAP_DUE or ~ACK_FROM_TAP_DUE.
 		 */
-		timerfd_settime(conn->timer, 0, &new, &old);
+		if (timerfd_settime(conn->timer, 0, &new, &old))
+			flow_err(conn, "failed to set timer: %s",
+				 strerror(errno));
+
 		if (old.it_value.tv_sec == ACT_TIMEOUT) {
 			flow_dbg(conn, "activity timeout");
 			tcp_rst(c, conn);
-- 
@@ -548,7 +548,8 @@ static void tcp_timer_ctl(const struct ctx *c, struct tcp_tap_conn *conn)
 		 (unsigned long long)it.it_value.tv_sec,
 		 (unsigned long long)it.it_value.tv_nsec / 1000 / 1000);
 
-	timerfd_settime(conn->timer, 0, &it, NULL);
+	if (timerfd_settime(conn->timer, 0, &it, NULL))
+		flow_err(conn, "failed to set timer: %s", strerror(errno));
 }
 
 /**
@@ -2240,7 +2241,9 @@ void tcp_timer_handler(const struct ctx *c, union epoll_ref ref)
 	 * timer is currently armed, this event came from a previous setting,
 	 * and we just set the timer to a new point in the future: discard it.
 	 */
-	timerfd_gettime(conn->timer, &check_armed);
+	if (timerfd_gettime(conn->timer, &check_armed))
+		flow_err(conn, "failed to read timer: %s", strerror(errno));
+
 	if (check_armed.it_value.tv_sec || check_armed.it_value.tv_nsec)
 		return;
 
@@ -2278,7 +2281,10 @@ void tcp_timer_handler(const struct ctx *c, union epoll_ref ref)
 		 * case. This avoids having to preemptively reset the timer on
 		 * ~ACK_TO_TAP_DUE or ~ACK_FROM_TAP_DUE.
 		 */
-		timerfd_settime(conn->timer, 0, &new, &old);
+		if (timerfd_settime(conn->timer, 0, &new, &old))
+			flow_err(conn, "failed to set timer: %s",
+				 strerror(errno));
+
 		if (old.it_value.tv_sec == ACT_TIMEOUT) {
 			flow_dbg(conn, "activity timeout");
 			tcp_rst(c, conn);
-- 
2.43.0