[Cluster-devel] [PATCH 06/10] dlm_controld: change dlm_options[] to shared memory type

[Heming Zhao <heming.zhao@suse.com>]

This commit makes dlm_options[] could be modified after fork().
The patch is foundation to dynamic setting feature.

Signed-off-by: Heming Zhao <heming.zhao@suse.com>
---
 dlm_controld/dlm_daemon.h |  2 +-
 dlm_controld/main.c       | 14 +++++++++++++-
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/dlm_controld/dlm_daemon.h b/dlm_controld/dlm_daemon.h
index 76f5f4d082a5..e20e98e78707 100644
--- a/dlm_controld/dlm_daemon.h
+++ b/dlm_controld/dlm_daemon.h
@@ -159,7 +159,7 @@ struct dlm_option {
 	unsigned int dynamic_uint;
 };
 
-EXTERN struct dlm_option dlm_options[dlm_options_max];
+EXTERN struct dlm_option *dlm_options;
 #define opt(x) dlm_options[x].use_int
 #define opts(x) dlm_options[x].use_str
 #define optu(x) dlm_options[x].use_uint
diff --git a/dlm_controld/main.c b/dlm_controld/main.c
index 504cafa12ec6..2a4f33b1b455 100644
--- a/dlm_controld/main.c
+++ b/dlm_controld/main.c
@@ -14,6 +14,7 @@
 #include <linux/genetlink.h>
 #include <linux/dlm_netlink.h>
 #include <uuid/uuid.h>
+#include <sys/mman.h>
 
 #ifdef USE_SD_NOTIFY
 #include <systemd/sd-daemon.h>
@@ -2104,11 +2105,21 @@ int main(int argc, char **argv)
 	struct sigaction act;
 	int fd, rv;
 
+	/* share the cfg memory for helper process */
+	dlm_options = mmap(NULL, sizeof(struct dlm_option)*dlm_options_max,
+						PROT_READ|PROT_WRITE, MAP_SHARED|MAP_ANON, -1, 0);
+	if (dlm_options == MAP_FAILED) {
+		perror("mmap failed");
+		return 1;
+	}
+
 	/*
-	 * config priority: cli, config file, default
+	 * config priority: dynamic, cli, config file, default
 	 * - explicit cli setting will override default,
 	 * - explicit file setting will override default
 	 * - explicit file setting will not override explicit cli setting
+	 * - explicit dynamic setting will override using value,
+	 *   "dlm_tool dump_config" will show which option is using dynamic setting.
 	 */
 
 	set_opt_defaults();
-- 
2.32.0