dmeventd_thin: add run_command

Implement forking of executable command.
When command is forked, dmeventd may continue monitor device.

diff --git a/daemons/dmeventd/plugins/thin/dmeventd_thin.c b/daemons/dmeventd/plugins/thin/dmeventd_thin.c
index b436524e1f44b54f3ed74743e75a65582fa36c7d..3e044ff6f8c58f7b43d7ad2d22d9c207cc017034 100644 (file)
--- a/daemons/dmeventd/plugins/thin/dmeventd_thin.c
+++ b/daemons/dmeventd/plugins/thin/dmeventd_thin.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2011-2016 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2011-2017 Red Hat, Inc. All rights reserved.
  *
  * This file is part of LVM2.
  *
@@ -55,6 +55,8 @@ struct dso_state {
        uint64_t known_metadata_size;
        uint64_t known_data_size;
        unsigned fails;
+       pid_t pid;
+       char **argv;
        char cmd_str[1024];
 };
 
@@ -302,19 +304,62 @@ out:
                dm_bitset_destroy(data.minors);
 }
 
+static int _run_command(struct dso_state *state)
+{
+       char val[2][36];
+       char *env[] = { val[0], val[1], NULL };
+       int i;
+
+       if (state->data_percent) {
+               /* Prepare some known data to env vars for easy use */
+               (void) dm_snprintf(val[0], sizeof(val[0]), "DMEVENTD_THIN_POOL_DATA=%d",
+                                  state->data_percent / DM_PERCENT_1);
+               (void) dm_snprintf(val[1], sizeof(val[1]), "DMEVENTD_THIN_POOL_METADATA=%d",
+                                  state->metadata_percent / DM_PERCENT_1);
+       } else {
+               /* For an error event it's for a user to check status and decide */
+               env[0] = NULL;
+               log_debug("Error event processing");
+       }
+
+       log_verbose("Executing command: %s", state->cmd_str);
+
+       /* TODO:
+        *   Support parallel run of 'task' and it's waitpid maintainence
+        *   ATM we can't handle signaling of  SIGALRM
+        *   as signalling is not allowed while 'process_event()' is running
+        */
+       if (!(state->pid = fork())) {
+               /* child */
+               (void) close(0);
+               for (i = 3; i < 255; ++i) (void) close(i);
+               execve(state->argv[0], state->argv, env);
+               _exit(errno);
+       } else if (state->pid == -1) {
+               log_error("Can't fork command %s.", state->cmd_str);
+               state->fails = 1;
+               return 0;
+       }
+
+       return 1;
+}
+
 static int _use_policy(struct dm_task *dmt, struct dso_state *state)
 {
 #if THIN_DEBUG
        log_debug("dmeventd executes: %s.", state->cmd_str);
 #endif
+       if (state->argv)
+               return _run_command(state);
+
        if (!dmeventd_lvm2_run_with_lock(state->cmd_str)) {
-               log_error("Failed to extend thin pool %s.",
-                         dm_task_get_name(dmt));
-               state->fails++;
+               log_error("Failed command for %s.", dm_task_get_name(dmt));
+               state->fails = 1;
                return 0;
        }
 
        state->fails = 0;
+
        return 1;
 }