Make signal handlers async-signal-safe

[browser-switch] / main.c

diff --git a/main.c b/main.c
index 2e19b84..6f6e95a 100644 (file)
--- a/main.c
+++ b/main.c
@@ -22,10 +22,12 @@
 
 #include <stdlib.h>
 #include <string.h>
 
 #include <stdlib.h>
 #include <string.h>

+#include <unistd.h>

 #include <signal.h>
 #include <errno.h>
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <signal.h>
 #include <errno.h>
 #include <sys/types.h>
 #include <sys/wait.h>

+#include <glib.h>

 #include <dbus/dbus-glib.h>
 
 #include "browser-switchboard.h"
 #include <dbus/dbus-glib.h>
 
 #include "browser-switchboard.h"

@@ -36,12 +38,60 @@
 
 struct swb_context ctx;
 
 
 struct swb_context ctx;
 

+static void read_config(void);
+
+/* Wait for zombies on SIGCHLD */

 static void waitforzombies(int signalnum) {
 static void waitforzombies(int signalnum) {

-       while (waitpid(-1, NULL, WNOHANG) > 0)
-               log_msg("Waited for a zombie\n");
+       while (waitpid(-1, NULL, WNOHANG) > 0);
+}
+
+/* Handle other signals in event loop by writing signal number to pipe */
+int eventpipe[2];
+static void handle_signal(int signalnum) {
+       write(eventpipe[1], &signalnum, sizeof signalnum);

 }
 
 }
 

-static void read_config(int signalnum) {
+/* Callbacks for polling the event pipe in the GLib event loop */
+static GPollFD fdevents_pfd;
+/* Called before entering the poll() */
+static gboolean fdevents_prepare(GSource *source, gint *timeout) {
+       /* No timeout for poll() */
+       *timeout = -1;
+       return FALSE;
+}
+/* Check to see whether a handled event has happened */
+static gboolean fdevents_check(GSource *source) {
+       return !!(fdevents_pfd.revents & G_IO_IN);
+}
+/* Read the event from the pipe and handle it */
+static gboolean fdevents_dispatch(GSource *source,
+                                 GSourceFunc callback, gpointer user_data) {
+       int eventnum;
+
+       if (read(eventpipe[0], &eventnum, sizeof eventnum) == (sizeof eventnum)) {
+               /* Handle the event passed to us */
+               switch (eventnum) {
+                 /* SIGHUP received -- reread config file */
+                 case SIGHUP:
+                       read_config();
+                       break;
+                 default:
+                       return FALSE;
+               }
+               return TRUE;
+       } else {
+               return FALSE;
+       }
+}
+static GSourceFuncs fdevents_funcs = {
+       .prepare = fdevents_prepare,
+       .check = fdevents_check,
+       .dispatch = fdevents_dispatch,
+       .finalize = NULL,
+};
+
+
+static void read_config(void) {

        struct swb_config cfg;
 
        swb_config_init(&cfg);
        struct swb_config cfg;
 
        swb_config_init(&cfg);

@@ -86,8 +136,9 @@ int main() {
        GMainLoop *mainloop;
        GError *error = NULL;
        int reqname_result;
        GMainLoop *mainloop;
        GError *error = NULL;
        int reqname_result;

+       GSource *fdevents;

 
 

-       read_config(0);
+       read_config();

 
        if (ctx.continuous_mode) {
                /* Install signal handlers */
 
        if (ctx.continuous_mode) {
                /* Install signal handlers */

@@ -102,8 +153,12 @@ int main() {
                        return 1;
                }
 
                        return 1;
                }
 

-               /* SIGHUP -- reread config file */
-               act.sa_handler = read_config;
+               /* All other signals are handled via the GLib main loop */
+               if (pipe(eventpipe) == -1) {
+                       log_perror(errno, "Creating event pipe failed");
+                       return 1;
+               }
+               act.sa_handler = handle_signal;

                if (sigaction(SIGHUP, &act, NULL) == -1) {
                        log_msg("Installing signal handler failed\n");
                        return 1;
                if (sigaction(SIGHUP, &act, NULL) == -1) {
                        log_msg("Installing signal handler failed\n");
                        return 1;

@@ -184,6 +239,18 @@ int main() {
                        G_OBJECT(obj_osso_browser_sys_req));
 
        mainloop = g_main_loop_new(NULL, FALSE);
                        G_OBJECT(obj_osso_browser_sys_req));
 
        mainloop = g_main_loop_new(NULL, FALSE);

+
+       /* Hook up event pipe to the main loop */
+       if (ctx.continuous_mode) {
+               fdevents = g_source_new(&fdevents_funcs, sizeof(GSource));
+               g_source_set_priority(fdevents, G_PRIORITY_HIGH);
+               fdevents_pfd.fd = eventpipe[0];
+               fdevents_pfd.events = G_IO_IN;
+               fdevents_pfd.revents = 0;
+               g_source_add_poll(fdevents, &fdevents_pfd);
+               g_source_attach(fdevents, NULL);
+       }
+

        log_msg("Starting main loop\n");
        g_main_loop_run(mainloop);
        log_msg("Main loop completed\n");
        log_msg("Starting main loop\n");
        g_main_loop_run(mainloop);
        log_msg("Main loop completed\n");