Disable polling in udev mode, use udev to signal device discovery

1 files changed, 43 insertions, 15 deletions

diff --git a/daemon/main.c b/daemon/main.c
index ef98e75..893f26d 100644
--- a/daemon/main.c
+++ b/daemon/main.c
@@ -48,6 +48,7 @@ static const char *socket_path = "/var/run/usbmuxd";
 static const char *lockfile = "/var/run/usbmuxd.pid";
 
 int should_exit;
+int should_discover;
 
 static int verbose = 0;
 static int foreground = 0;
@@ -96,21 +97,26 @@ int create_socket(void) {
 
 void handle_signal(int sig)
 {
-        if (sig != SIGUSR1) {
+        if (sig != SIGUSR1 && sig != SIGUSR2) {
                 usbmuxd_log(LL_NOTICE,"Caught signal %d, exiting", sig);
                 should_exit = 1;
         } else {
                 if(opt_udev) {
-                        usbmuxd_log(LL_INFO, "Caught SIGUSR1, checking if we can terminate (no more devices attached)...");
-                        if (device_get_count() > 0) {
-                                // we can't quit, there are still devices attached.
-                                usbmuxd_log(LL_NOTICE, "Refusing to terminate, there are still devices attached. Kill me with signal 15 (TERM) to force quit.");
-                        } else {
-                                // it's safe to quit
-                                should_exit = 1;
+                        if (sig == SIGUSR1) {
+                                usbmuxd_log(LL_INFO, "Caught SIGUSR1, checking if we can terminate (no more devices attached)...");
+                                if (device_get_count() > 0) {
+                                        // we can't quit, there are still devices attached.
+                                        usbmuxd_log(LL_NOTICE, "Refusing to terminate, there are still devices attached. Kill me with signal 15 (TERM) to force quit.");
+                                } else {
+                                        // it's safe to quit
+                                        should_exit = 1;
+                                }
+                        } else if (sig == SIGUSR2) {
+                                usbmuxd_log(LL_INFO, "Caught SIGUSR2, scheduling device discovery");
+                                should_discover = 1;
                         }
                 } else {
-                        usbmuxd_log(LL_INFO, "Caught SIGUSR1 but we weren't started in --udev mode, ignoring");
+                        usbmuxd_log(LL_INFO, "Caught SIGUSR1/2 but we weren't started in --udev mode, ignoring");
                 }
         }
 }
@@ -124,6 +130,7 @@ void set_signal_handlers(void)
         sigaction(SIGQUIT, &sa, NULL);
         sigaction(SIGTERM, &sa, NULL);
         sigaction(SIGUSR1, &sa, NULL);
+        sigaction(SIGUSR2, &sa, NULL);
 }
 
 int main_loop(int listenfd)
@@ -150,10 +157,17 @@ int main_loop(int listenfd)
                 usbmuxd_log(LL_FLOOD, "poll() returned %d", cnt);
 
                 if(cnt == -1) {
-                        if(errno == EINTR && should_exit) {
-                                usbmuxd_log(LL_INFO, "event processing interrupted");
-                                fdlist_free(&pollfds);
-                                return 0;
+                        if(errno == EINTR) {
+                                if(should_exit) {
+                                        usbmuxd_log(LL_INFO, "event processing interrupted");
+                                        fdlist_free(&pollfds);
+                                        return 0;
+                                }
+                                if(should_discover) {
+                                        should_discover = 0;
+                                        usbmuxd_log(LL_INFO, "device discovery triggered by udev");
+                                        usb_discover();
+                                }
                         }
                 } else if(cnt == 0) {
                         if(usb_process() < 0) {
@@ -391,6 +405,7 @@ int main(int argc, char *argv[])
 
         usbmuxd_log(LL_NOTICE, "usbmux v%s starting up", USBMUXD_VERSION);
         should_exit = 0;
+        should_discover = 0;
 
         set_signal_handlers();
 
@@ -425,8 +440,18 @@ int main(int argc, char *argv[])
                                 usbmuxd_log(LL_ERROR, "Another instance is already running (pid %d). exiting.", lock.l_pid);
                                 res = -1;
                         } else {
-                                usbmuxd_log(LL_NOTICE, "Another instance is already running (pid %d). exiting.", lock.l_pid);
-                                res = 0;
+                                usbmuxd_log(LL_NOTICE, "Another instance is already running (pid %d). Telling it to check for devices.", lock.l_pid);
+                                if (lock.l_pid && !kill(lock.l_pid, 0)) {
+                                        usbmuxd_log(LL_NOTICE, "Sending signal SIGUSR2 to instance with pid %d", lock.l_pid);
+                                        res = 0;
+                                        if (kill(lock.l_pid, SIGUSR2) < 0) {
+                                                usbmuxd_log(LL_FATAL, "Could not deliver SIGUSR2 to pid %d", lock.l_pid);
+                                                res = -1;
+                                        }
+                                } else {
+                                        usbmuxd_log(LL_ERROR, "Could not determine pid of the other running instance!");
+                                        res = -1;
+                                }
                         }
                         goto terminate;
                 }
@@ -523,6 +548,9 @@ int main(int argc, char *argv[])
                 if((res = notify_parent(0)) < 0)
                         goto terminate;
 
+        if(opt_udev)
+                usb_autodiscover(0); // discovery triggered by udev
+
         res = main_loop(listenfd);
         if(res < 0)
                 usbmuxd_log(LL_FATAL, "main_loop failed");