Use sigaction instead of a signal handler to wait for the SIGHUP

1 files changed, 12 insertions, 21 deletions

diff --git a/jaildaemon.c b/jaildaemon.c
index 3ae8612..7dad058 100644
--- a/jaildaemon.c
+++ b/jaildaemon.c
@@ -36,7 +36,6 @@ typedef struct {
 } daemon_task;
 
 /* Forward declarations */
-static void  signal_handler( int signal );
 static void  term_handler( int signal );
 static void  kill_all_probes( void );
 static int   check_for_jail( int jid );
@@ -49,14 +48,8 @@ static void  exerr( char * message );
 static void  warn( char * message );
 static void  usage( char * command );
 
-/* This is the handler installed in the jailed process. It will exit with the
-   proper exit code to make the host system daemon recognize the process has
-   deliberately killed itself and was not just shutdown with the jail */
-static void signal_handler( int signal ) {
-    if( signal == SIGHUP )
-        _exit( MAGIC_EXIT_CODE );
-}
-
+/* This handler ensures that we clean up our probes if asked to terminate
+   gracefully */
 static void term_handler( int signal ) {
     if( signal == SIGTERM )
         exit(0);
@@ -174,28 +167,27 @@ static int check_for_jail( int jid ) {
 }
 
 static pid_t fork_and_jail( int jid, char * proctitle ) {
+    int sig;
     pid_t pid = fork();
     if( !pid ) {
-        struct sigaction sa;
+        sigset_t sigset;
 
         /* Set proctitle so that jail's pgrep -f can identify the process */
         if( proctitle && *proctitle )
             setproctitle( "%s", proctitle );
 
-        /* Setup signal handler for SIGHUP */
-        sa.sa_handler = signal_handler;
-        sigemptyset(&sa.sa_mask);
-        sa.sa_flags = SA_RESTART;
-        if( sigaction(SIGHUP, &sa, NULL) == -1 )
-            exerr( "when install signal handler" );
-
         /* Throw ourself into the jail */
         if( jail_attach( jid ) )
             exerr( "when attaching to jail" );
 
-        /* Spin and wait for SIGHUP */
-        while( 1 )
-            sleep(32);
+        /* wait for SIGHUP */
+        sigemptyset(&sigset);
+        sigaddset(&sigset, SIGHUP);
+        sigprocmask(SIG_BLOCK, &sigset, NULL);
+        while( !sigwait( &sigset, &sig ) )
+            if( sig == SIGHUP )
+                exit( MAGIC_EXIT_CODE );
+        exit(0);
     }
     return pid;
 }
@@ -281,7 +273,6 @@ static void fork_and_execve( int kq, daemon_task * t_in ) {
 
 static void kill_all_probes( void ) {
     size_t i;
-syslog( LOG_ERR, "KILLING PROBES" );
     if( g_probes )
         for( i = 0; i < g_probes_size; ++i )
             if( g_probes[i] )