Remove bgw_sighup and bgw_sigterm.

robertmhaas · robertmhaas · commit 295f9bbf1d2d · 2013-07-22T15:15:22.000-04:00
Per discussion on pgsql-hackers, these aren't really needed.  Interim
versions of the background worker patch had the worker starting with
signals already unblocked, which would have made this necessary.
But the final version does not, so we don't really need it; and it
doesn't work well with the new facility for starting dynamic background
workers, so just rip it out.

Also per discussion on pgsql-hackers, back-patch this change to 9.3.
It's best to get the API break out of the way before we do an
official release of this facility, to avoid more pain for extension
authors later.
diff --git a/contrib/worker_spi/worker_spi.c b/contrib/worker_spi/worker_spi.c
@@ -159,6 +159,10 @@ worker_spi_main(void *main_arg)
 	worktable  *table = (worktable *) main_arg;
 	StringInfoData buf;
 
+	/* Establish signal handlers before unblocking signals. */
+	pqsignal(SIGHUP, worker_spi_sighup);
+	pqsignal(SIGTERM, worker_spi_sigterm);
+
 	/* We're now ready to receive signals */
 	BackgroundWorkerUnblockSignals();
 
@@ -328,8 +332,6 @@ _PG_init(void)
 	worker.bgw_start_time = BgWorkerStart_RecoveryFinished;
 	worker.bgw_restart_time = BGW_NEVER_RESTART;
 	worker.bgw_main = worker_spi_main;
-	worker.bgw_sighup = worker_spi_sighup;
-	worker.bgw_sigterm = worker_spi_sigterm;
 
 	/*
 	 * Now fill in worker-specific data, and do the actual registrations.
diff --git a/doc/src/sgml/bgworker.sgml b/doc/src/sgml/bgworker.sgml
@@ -38,7 +38,6 @@
   The structure <structname>BackgroundWorker</structname> is defined thus:
 <programlisting>
 typedef void (*bgworker_main_type)(void *main_arg);
-typedef void (*bgworker_sighdlr_type)(SIGNAL_ARGS);
 typedef struct BackgroundWorker
 {
     char       *bgw_name;
@@ -47,8 +46,6 @@ typedef struct BackgroundWorker
     int         bgw_restart_time;       /* in seconds, or BGW_NEVER_RESTART */
     bgworker_main_type  bgw_main;
     void       *bgw_main_arg;
-    bgworker_sighdlr_type bgw_sighup;
-    bgworker_sighdlr_type bgw_sigterm;
 } BackgroundWorker;
 </programlisting>
   </para>
@@ -104,14 +101,6 @@ typedef struct BackgroundWorker
    passed at registration time.
   </para>
 
-  <para>
-   <structfield>bgw_sighup</structfield> and <structfield>bgw_sigterm</> are
-   pointers to functions that will be installed as signal handlers for the new
-   process.  If <structfield>bgw_sighup</> is NULL, then <literal>SIG_IGN</>
-   is used; if <structfield>bgw_sigterm</> is NULL, a handler is installed that
-   will terminate the process after logging a suitable message.
-  </para>
-
   <para>Once running, the process can connect to a database by calling
    <function>BackgroundWorkerInitializeConnection(<parameter>char *dbname</parameter>, <parameter>char *username</parameter>)</function>.
    This allows the process to run transactions and queries using the
@@ -126,7 +115,7 @@ typedef struct BackgroundWorker
   <para>
    Signals are initially blocked when control reaches the
    <structfield>bgw_main</> function, and must be unblocked by it; this is to
-   allow the process to further customize its signal handlers, if necessary.
+   allow the process to customize its signal handlers, if necessary.
    Signals can be unblocked in the new process by calling
    <function>BackgroundWorkerUnblockSignals</> and blocked by calling
    <function>BackgroundWorkerBlockSignals</>.
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
@@ -5434,16 +5434,8 @@ do_start_bgworker(void)
 		pqsignal(SIGFPE, SIG_IGN);
 	}
 
-	/* SIGTERM and SIGHUP are configurable */
-	if (worker->bgw_sigterm)
-		pqsignal(SIGTERM, worker->bgw_sigterm);
-	else
-		pqsignal(SIGTERM, bgworker_die);
-
-	if (worker->bgw_sighup)
-		pqsignal(SIGHUP, worker->bgw_sighup);
-	else
-		pqsignal(SIGHUP, SIG_IGN);
+	pqsignal(SIGTERM, bgworker_die);
+	pqsignal(SIGHUP, SIG_IGN);
 
 	pqsignal(SIGQUIT, bgworker_quickdie);
 	InitializeTimeouts();		/* establishes SIGALRM handler */
diff --git a/src/include/postmaster/bgworker.h b/src/include/postmaster/bgworker.h
@@ -53,7 +53,6 @@
 
 
 typedef void (*bgworker_main_type) (void *main_arg);
-typedef void (*bgworker_sighdlr_type) (SIGNAL_ARGS);
 
 /*
  * Points in time at which a bgworker can request to be started
@@ -76,8 +75,6 @@ typedef struct BackgroundWorker
 	int			bgw_restart_time;		/* in seconds, or BGW_NEVER_RESTART */
 	bgworker_main_type bgw_main;
 	void	   *bgw_main_arg;
-	bgworker_sighdlr_type bgw_sighup;
-	bgworker_sighdlr_type bgw_sigterm;
 } BackgroundWorker;
 
 /* Register a new bgworker */
