[pve-devel] [PATCH ha-manager v2 5/5] watchdog-mux: sync journal right after fencing warning

[Maximiliano Sandoval <m.sandoval@proxmox.com>]

Since this journal entry can be logged multiple times in the lifespan on
the process, we double fork to prevent accumulating zombie processes.

Signed-off-by: Maximiliano Sandoval <m.sandoval@proxmox.com>
---
 src/watchdog-mux.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/src/watchdog-mux.c b/src/watchdog-mux.c
index 2287625..93f9bd9 100644
--- a/src/watchdog-mux.c
+++ b/src/watchdog-mux.c
@@ -12,6 +12,7 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <sys/un.h>
+#include <sys/wait.h>
 #include <time.h>
 #include <unistd.h>
 
@@ -116,6 +117,22 @@ static void sync_journal_unsafe(void) {
     }
 }
 
+// Like sync_journal_unsafe but we double fork so we don't leave trailing zombie
+// processes.
+static void sync_journal_in_fork(void) {
+    pid_t child = fork();
+    if (child == 0) {
+        child = fork();
+        if (child == 0) {
+            execl(JOURNALCTL_BIN, JOURNALCTL_BIN, "--sync", NULL);
+            exit(-1);
+        }
+        exit(0);
+    } else if (child > 0) {
+        wait(NULL);
+    }
+}
+
 int main(void) {
     struct sockaddr_un my_addr, peer_addr;
     socklen_t peer_addr_size;
@@ -254,6 +271,7 @@ int main(void) {
                             (ctime - client_list[i].time) > CLIENT_WATCHDOG_TIMEOUT_WARNING) {
                             client_list[i].warning_state = WARNING_ISSUED;
                             fprintf(stderr, "client watchdog is about to expire\n");
+                            sync_journal_in_fork();
                         }
 
                         if ((ctime - client_list[i].time) > CLIENT_WATCHDOG_TIMEOUT) {
-- 
2.39.5



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