udev-spawn: refuse to spawn commands if the event already takes too long

Also, calculate the timeout for warning based on the remaining time for
the timeout of the event, rather than the timeout itself.

Currently, udev manager kills the worker if the timeout exceeds. So,
this does not change anything except for the timing of the warning.

Just refactoring and preparation for later commits.

diff --git a/src/udev/udev-spawn.c b/src/udev/udev-spawn.c
index 998b1759c4955b46f2d6081035cadfae24b4dab9..4fb5b548a38a4bd7adb16e38f8d2a4f0dab8b94a 100644 (file)
--- a/src/udev/udev-spawn.c
+++ b/src/udev/udev-spawn.c
@@ -23,6 +23,7 @@ typedef struct Spawn {
         usec_t timeout_usec;
         int timeout_signal;
         usec_t event_birth_usec;
+        usec_t cmd_birth_usec;
         bool accept_failure;
         int fd_stdout;
         int fd_stderr;
@@ -163,31 +164,20 @@ static int spawn_wait(Spawn *spawn) {
         if (r < 0)
                 return log_device_debug_errno(spawn->device, r, "Failed to allocate sd-event object: %m");
 
-        if (spawn->timeout_usec > 0) {
-                usec_t usec, age_usec;
-
-                usec = now(CLOCK_MONOTONIC);
-                age_usec = usec - spawn->event_birth_usec;
-                if (age_usec < spawn->timeout_usec) {
-                        if (spawn->timeout_warn_usec > 0 &&
-                            spawn->timeout_warn_usec < spawn->timeout_usec &&
-                            spawn->timeout_warn_usec > age_usec) {
-                                spawn->timeout_warn_usec -= age_usec;
-
-                                r = sd_event_add_time(e, NULL, CLOCK_MONOTONIC,
-                                                      usec + spawn->timeout_warn_usec, USEC_PER_SEC,
-                                                      on_spawn_timeout_warning, spawn);
-                                if (r < 0)
-                                        return log_device_debug_errno(spawn->device, r, "Failed to create timeout warning event source: %m");
-                        }
-
-                        spawn->timeout_usec -= age_usec;
-
+        if (spawn->timeout_usec != USEC_INFINITY) {
+                if (spawn->timeout_warn_usec < spawn->timeout_usec) {
                         r = sd_event_add_time(e, NULL, CLOCK_MONOTONIC,
-                                              usec + spawn->timeout_usec, USEC_PER_SEC, on_spawn_timeout, spawn);
+                                              usec_add(spawn->cmd_birth_usec, spawn->timeout_warn_usec), USEC_PER_SEC,
+                                              on_spawn_timeout_warning, spawn);
                         if (r < 0)
-                                return log_device_debug_errno(spawn->device, r, "Failed to create timeout event source: %m");
+                                return log_device_debug_errno(spawn->device, r, "Failed to create timeout warning event source: %m");
                 }
+
+                r = sd_event_add_time(e, NULL, CLOCK_MONOTONIC,
+                                      usec_add(spawn->cmd_birth_usec, spawn->timeout_usec), USEC_PER_SEC,
+                                      on_spawn_timeout, spawn);
+                if (r < 0)
+                        return log_device_debug_errno(spawn->device, r, "Failed to create timeout event source: %m");
         }
 
         if (spawn->fd_stdout >= 0) {
@@ -240,6 +230,13 @@ int udev_event_spawn(
 
         int timeout_signal = event->worker ? event->worker->timeout_signal : SIGKILL;
         usec_t timeout_usec = event->worker ? event->worker->timeout_usec : DEFAULT_WORKER_TIMEOUT_USEC;
+        usec_t now_usec = now(CLOCK_MONOTONIC);
+        usec_t age_usec = usec_sub_unsigned(now_usec, event->birth_usec);
+        usec_t cmd_timeout_usec = usec_sub_unsigned(timeout_usec, age_usec);
+        if (cmd_timeout_usec <= 0)
+                return log_device_warning_errno(event->dev, SYNTHETIC_ERRNO(ETIME),
+                                                "The event already takes longer (%s) than the timeout (%s), skipping execution of '%s'.",
+                                                FORMAT_TIMESPAN(age_usec, 1), FORMAT_TIMESPAN(timeout_usec, 1), cmd);
 
         /* pipes from child to parent */
         if (result || log_get_max_level() >= LOG_INFO)
@@ -300,10 +297,11 @@ int udev_event_spawn(
                 .cmd = cmd,
                 .pid = pid,
                 .accept_failure = accept_failure,
-                .timeout_warn_usec = udev_warn_timeout(timeout_usec),
-                .timeout_usec = timeout_usec,
+                .timeout_warn_usec = udev_warn_timeout(cmd_timeout_usec),
+                .timeout_usec = cmd_timeout_usec,
                 .timeout_signal = timeout_signal,
                 .event_birth_usec = event->birth_usec,
+                .cmd_birth_usec = now_usec,
                 .fd_stdout = outpipe[READ_END],
                 .fd_stderr = errpipe[READ_END],
                 .result = result,