On 30/12/2018 21:59, Heikki Linnakangas wrote:
On 28/12/2018 22:13, Tom Lane wrote:
Heikki Linnakangas <hlinn...@iki.fi> writes:
Another idea would be to call setsid() in pg_ctl, after forking
postmaster, like in Paul's original patch. That solves 1. and 2. To
still do 3., add a signal handler for SIGINT in pg_ctl, which forwards
the SIGINT to the postmaster process. Thoughts on that?
That seems like a nice idea.
Here's a patch to implement that.
Forgot attachment, here it is.
- Heikki
diff --git a/src/bin/pg_ctl/pg_ctl.c b/src/bin/pg_ctl/pg_ctl.c
index 1d0b056dde0..cb7b88bc7df 100644
--- a/src/bin/pg_ctl/pg_ctl.c
+++ b/src/bin/pg_ctl/pg_ctl.c
@@ -103,12 +103,13 @@ static char backup_file[MAXPGPATH];
static char promote_file[MAXPGPATH];
static char logrotate_file[MAXPGPATH];
+static volatile pgpid_t postmasterPID = -1;
+
#ifdef WIN32
static DWORD pgctl_start_type = SERVICE_AUTO_START;
static SERVICE_STATUS status;
static SERVICE_STATUS_HANDLE hStatus = (SERVICE_STATUS_HANDLE) 0;
static HANDLE shutdownHandles[2];
-static pid_t postmasterPID = -1;
#define shutdownEvent shutdownHandles[0]
#define postmasterProcess shutdownHandles[1]
@@ -471,6 +472,20 @@ start_postmaster(void)
/* fork succeeded, in child */
+ /*
+ * If possible, detach the postmaster process from the launching process group
+ * and make it a group leader, so that it doesn't get signaled along with the
+ * current group that launched it.
+ */
+#ifdef HAVE_SETSID
+ if (setsid() < 0)
+ {
+ write_stderr(_("%s: could not start server due to setsid() failure: %s\n"),
+ progname, strerror(errno));
+ exit(1);
+ }
+#endif
+
/*
* Since there might be quotes to handle here, it is easier simply to pass
* everything to a shell to process them. Use exec so that the postmaster
@@ -719,6 +734,30 @@ read_post_opts(void)
}
}
+/*
+ * SIGINT signal handler used while waiting for postmaster to start up.
+ * Forwards the SIGINT to the postmaster process, asking it to shut down,
+ * before terminating pg_ctl itself. This way, if the user hits CTRL-C while
+ * waiting for the server to start up, the server launch is aborted.
+ */
+static void
+trap_sigint_during_startup(int sig)
+{
+ if (postmasterPID != -1)
+ {
+ if (kill(postmasterPID, SIGINT) != 0)
+ write_stderr(_("%s: could not send stop signal (PID: %ld): %s\n"),
+ progname, (pgpid_t) postmasterPID, strerror(errno));
+ }
+
+ /*
+ * Clear the signal handler, and send the signal again, to terminate the
+ * process as normal.
+ */
+ pqsignal(SIGINT, SIG_DFL);
+ raise(SIGINT);
+}
+
static char *
find_other_exec_or_die(const char *argv0, const char *target, const char *versionstr)
{
@@ -827,6 +866,17 @@ do_start(void)
if (do_wait)
{
+ /*
+ * If the user hits interrupts the startup (e.g. with CTRL-C), we'd
+ * like to abort the server launch. Install a signal handler that
+ * will forward SIGINT to the postmaster process, while we wait.
+ *
+ * (We don't bother to reset the signal handler after the launch,
+ * as we're about to exit, anyway.)
+ */
+ postmasterPID = pm_pid;
+ pqsignal(SIGINT, trap_sigint_during_startup);
+
print_msg(_("waiting for server to start..."));
switch (wait_for_postmaster(pm_pid, false))
