LP1204123 SIGUSR2 causes router re-register (Perl/C)

When a listener process receives the USR2 signal, the 'register' command
is sent to all known routers.  This allows for the addition of new
routers to running opensrf services.

If a register command is sent to a router for which the process is
already successfully register, the router will safely discard it, so
multiple SIGUSR2 calls are safe.

Minor int => bool clarification repair to existing C shutdown
(prefork_clear) code.

Signed-off-by: Bill Erickson <berick@esilibrary.com>
Signed-off-by: Jason Stephenson <jstephenson@mvlc.org>

diff --git a/src/libopensrf/osrf_prefork.c b/src/libopensrf/osrf_prefork.c
index aab8005..d2537e3 100644 (file)
--- a/src/libopensrf/osrf_prefork.c
+++ b/src/libopensrf/osrf_prefork.c
@@ -101,13 +101,14 @@ static prefork_child* prefork_child_init( prefork_simple* forker,
 
 /* listens on the 'data_to_child' fd and wait for incoming data */
 static void prefork_child_wait( prefork_child* child );
-static void prefork_clear( prefork_simple*, int graceful);
+static void prefork_clear( prefork_simple*, bool graceful);
 static void prefork_child_free( prefork_simple* forker, prefork_child* );
 static void osrf_prefork_register_routers( const char* appname, bool unregister );
 static void osrf_prefork_child_exit( prefork_child* );
 
 static void sigchld_handler( int sig );
 static void sigusr1_handler( int sig );
+static void sigusr2_handler( int sig );
 static void sigterm_handler( int sig );
 static void sigint_handler( int sig );
 
@@ -202,6 +203,7 @@ int osrf_prefork_run( const char* appname ) {
        osrf_prefork_register_routers( appname, false );
 
        signal( SIGUSR1, sigusr1_handler);
+       signal( SIGUSR2, sigusr2_handler);
        signal( SIGTERM, sigterm_handler);
        signal( SIGINT,  sigint_handler );
        signal( SIGQUIT, sigint_handler );
@@ -211,7 +213,7 @@ int osrf_prefork_run( const char* appname ) {
        prefork_run( &forker );
 
        osrfLogWarning( OSRF_LOG_MARK, "prefork_run() returned - how??" );
-       prefork_clear( &forker, 0 );
+       prefork_clear( &forker, false );
        return 0;
 }
 
@@ -616,6 +618,7 @@ static prefork_child* launch_child( prefork_simple* forker ) {
 
                // we don't want to adopt our parent's handlers.
                signal( SIGUSR1, SIG_DFL );
+               signal( SIGUSR2, SIG_DFL );
                signal( SIGTERM, SIG_DFL );
                signal( SIGINT,  SIG_DFL );
                signal( SIGQUIT, SIG_DFL );
@@ -691,6 +694,18 @@ static void sigusr1_handler( int sig ) {
 }
 
 /**
+       @brief Signal handler for SIGUSR2
+       @param sig The value of the trapped signal; always SIGUSR2.
+
+       Send register command to all known routers
+*/
+static void sigusr2_handler( int sig ) {
+       if (!global_forker) return;
+       osrf_prefork_register_routers(global_forker->appname, false);
+       signal( SIGUSR2, sigusr2_handler );
+}
+
+/**
        @brief Signal handler for SIGTERM
        @param sig The value of the trapped signal; always SIGTERM
 
@@ -699,7 +714,7 @@ static void sigusr1_handler( int sig ) {
 static void sigterm_handler(int sig) {
        if (!global_forker) return;
        osrfLogInfo(OSRF_LOG_MARK, "server: received SIGTERM, shutting down");
-       prefork_clear(global_forker, 1);
+       prefork_clear(global_forker, true);
        _exit(0);
 }
 
@@ -712,7 +727,7 @@ static void sigterm_handler(int sig) {
 static void sigint_handler(int sig) {
        if (!global_forker) return;
        osrfLogInfo(OSRF_LOG_MARK, "server: received SIGINT/QUIT, shutting down");
-       prefork_clear(global_forker, 0);
+       prefork_clear(global_forker, false);
        _exit(0);
 }
 
@@ -1233,7 +1248,7 @@ static prefork_child* prefork_child_init( prefork_simple* forker,
 
        We do not deallocate the prefork_simple itself, just its contents.
 */
-static void prefork_clear( prefork_simple* prefork, int graceful ) {
+static void prefork_clear( prefork_simple* prefork, bool graceful ) {
 
        // always de-register routers before killing child processes (or waiting
        // for them to complete) so that new requests are directed elsewhere.

diff --git a/src/perl/lib/OpenSRF/Server.pm b/src/perl/lib/OpenSRF/Server.pm
index 849e606..48197a7 100644 (file)
--- a/src/perl/lib/OpenSRF/Server.pm
+++ b/src/perl/lib/OpenSRF/Server.pm
@@ -146,6 +146,7 @@ sub run {
     $SIG{CHLD} = sub { $self->reap_children(); };
     $SIG{HUP} = sub { $self->handle_sighup(); };
     $SIG{USR1} = sub { $self->unregister_routers; };
+    $SIG{USR2} = sub { $self->register_routers; };
 
     $self->spawn_children;
     $self->build_osrf_handle;