Ignore SIGPIPE when using api server

Wmediumd exits with unhandled signal because signal SIGPIPE is received
when wmediumd tries to write closed api socket. So, set wmediumd to
ignore SIGPIPE and check write result to handle writing to closed client
socket.

Bug: 201616800
Test: lunch aosp_cf_x86_64_phone-userdebug &&
      m PRODUCT_ENFORCE_MAC80211_HWSIM=true droid wmediumd &&
      launch_cvd --ap_rootfs_image=$(path for OpenWRT image) \
                 --ap_kernel_image=$(path for OpenWRT kernel image)

      And then, control wmediumd with wmediumd_control

Change-Id: I07428695c8f5a2469b429f7d0b5e33091ad9b985

1 files changed, 23 insertions, 4 deletions

diff --git a/wmediumd/wmediumd.c b/wmediumd/wmediumd.c
index 8a59782..1f91508 100644
--- a/wmediumd/wmediumd.c
+++ b/wmediumd/wmediumd.c
@@ -275,6 +275,8 @@ static void wmediumd_wait_for_client_ack(struct wmediumd *ctx,
 		usfstl_loop_wait_and_handle();
 }
 
+static void wmediumd_remove_client(struct wmediumd *ctx, struct client *client);
+
 static void wmediumd_notify_frame_start(struct usfstl_job *job)
 {
 	struct frame *frame = container_of(job, struct frame, start_job);
@@ -304,7 +306,11 @@ static void wmediumd_notify_frame_start(struct usfstl_job *job)
 		/* must be API socket since flags cannot otherwise be set */
 		assert(client->type == CLIENT_API_SOCK);
 
-		write(client->loop.fd, &msg, sizeof(msg));
+		if (write(client->loop.fd, &msg, sizeof(msg)) < sizeof(msg)) {
+			usfstl_loop_unregister(&client->loop);
+			wmediumd_remove_client(ctx, client);
+			continue;
+		}
 
 		wmediumd_wait_for_client_ack(ctx, client);
 	}
@@ -548,11 +554,22 @@ static void wmediumd_send_to_client(struct wmediumd *ctx,
 		len = nlmsg_total_size(nlmsg_datalen(nlmsg_hdr(msg)));
 		hdr.type = WMEDIUMD_MSG_NETLINK;
 		hdr.data_len = len;
-		write(client->loop.fd, &hdr, sizeof(hdr));
-		write(client->loop.fd, (void *)nlmsg_hdr(msg), len);
+
+		if (write(client->loop.fd, &hdr, sizeof(hdr)) < sizeof(hdr))
+			goto disconnect;
+
+		if (write(client->loop.fd, (void *)nlmsg_hdr(msg), len) < len)
+			goto disconnect;
+
 		wmediumd_wait_for_client_ack(ctx, client);
 		break;
 	}
+
+	return;
+
+	disconnect:
+	usfstl_loop_unregister(&client->loop);
+	wmediumd_remove_client(ctx, client);
 }
 
 static void wmediumd_remove_client(struct wmediumd *ctx, struct client *client)
@@ -1398,8 +1415,10 @@ int main(int argc, char *argv[])
 			w_logf(&ctx, LOG_NOTICE, "REGISTER SENT!\n");
 	}
 
-	if (api_socket)
+	if (api_socket) {
+		signal(SIGPIPE, SIG_IGN);
 		usfstl_uds_create(api_socket, wmediumd_api_connected, &ctx);
+	}
 
 	if (time_socket) {
 		usfstl_sched_ctrl_start(&ctrl, time_socket,