Improve bin/tncd.c

Changes:

    * Ensure TNC PTYs are closed on error

    * Instead of waiting indefinitely, use patty_client_ping() to poll
      the status of the patty daemon to exit in a timely manner

bin/tncd.c

@@ -32,6 +32,37 @@ static void usage(int argc, char **argv, const char *message, ...) {
     exit(EX_USAGE);
 }
 
+static int pty_close(patty_client *client, int fd) {
+    enum patty_client_call call = PATTY_CLIENT_CLOSE;
+
+    patty_client_close_request request = {
+        .fd = fd
+    };
+
+    patty_client_close_response response;
+
+    if (patty_client_write(client, &call, sizeof(call)) < 0) {
+        goto error_io;
+    }
+
+    if (patty_client_write(client, &request, sizeof(request)) < 0) {
+        goto error_io;
+    }
+
+    if (patty_client_read(client, &response, sizeof(response)) < 0) {
+        goto error_io;
+    }
+
+    if (response.ret < 0) {
+        errno = response.eno;
+    }
+
+    return response.ret;
+
+error_io:
+    return -1;
+}
+
 static int pty_promisc(patty_client *client,
                        const char *ifname,
                        char *pty,
@@ -112,13 +143,13 @@ static int pty_promisc(patty_client *client,
 
     strncpy(pty, socket_response.path, len);
 
-    return 0;
+    return socket_response.fd;
 
 error_client_setsockopt:
 error_client_read_setsockopt_response:
 error_client_write_ifreq:
 error_client_write_setsockopt_request:
-    /* TODO: Close socket on error */
+    (void)pty_close(client, socket_response.fd);
 
 error_client_socket:
 error_client_read_socket_response:
@@ -132,6 +163,8 @@ int main(int argc, char **argv) {
     };
 
     patty_client *client;
+
+    int fd;
     char pty[256];
 
     if (getopt_long(argc, argv, "", opts, NULL) >= 0) {
@@ -149,22 +182,38 @@ int main(int argc, char **argv) {
         goto error_client_new;
     }
 
-    if (pty_promisc(client, argv[2], pty, sizeof(pty)) < 0) {
+    if ((fd = pty_promisc(client, argv[2], pty, sizeof(pty))) < 0) {
         fprintf(stderr, "%s: %s: %s: %s\n",
             argv[0], "pty_promisc()", argv[2], strerror(errno));
 
         goto error_pty_promisc;
     }
 
-    printf("%s\n", pty);
+    printf("pty %s\n", pty);
 
     while (1) {
-        sleep(86400);
+        int pong;
+
+        if ((pong = patty_client_ping(client)) < 0) {
+            fprintf(stderr, "%s: %s: %s\n",
+                argv[0], "patty_client_ping()", strerror(errno));
+
+            goto error_client_ping;
+        } else if (pong == 0) {
+            break;
+        }
+
+        sleep(2);
     }
 
     patty_client_destroy(client);
 
+error_client_ping:
+    (void)pty_close(client, fd);
+
 error_pty_promisc:
+    patty_client_destroy(client);
+
 error_client_new:
     return 1;
 }