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

3 files changed, 56 insertions, 16 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");
diff --git a/daemon/usb-linux.c b/daemon/usb-linux.c
index 0edc557..1f70f46 100644
--- a/daemon/usb-linux.c
+++ b/daemon/usb-linux.c
@@ -53,6 +53,7 @@ static struct collection device_list;
 static struct timeval next_dev_poll_time;
 
 static int devlist_failures;
+static int device_polling;
 
 static void usb_disconnect(struct usb_device *dev)
 {
@@ -214,7 +215,7 @@ static int start_rx(struct usb_device *dev)
         return 0;
 }
 
-static int usb_discover(void)
+int usb_discover(void)
 {
         int cnt, i, res;
         int valid_count = 0;
@@ -393,10 +394,18 @@ void usb_get_fds(struct fdlist *list)
         free(usbfds);
 }
 
+void usb_autodiscover(int enable)
+{
+        usbmuxd_log(LL_DEBUG, "usb polling enable: %d", enable);
+        device_polling = enable;
+}
+
 static int dev_poll_remain_ms(void)
 {
         int msecs;
         struct timeval tv;
+        if(!device_polling)
+                return 100000; // devices will never be polled if this is > 0
         gettimeofday(&tv, NULL);
         msecs = (next_dev_poll_time.tv_sec - tv.tv_sec) * 1000;
         msecs += (next_dev_poll_time.tv_usec - tv.tv_usec) / 1000;
@@ -493,6 +502,7 @@ int usb_init(void)
         usbmuxd_log(LL_DEBUG, "usb_init for linux / libusb 1.0");
 
         devlist_failures = 0;
+        device_polling = 1;
         res = libusb_init(NULL);
         //libusb_set_debug(NULL, 3);
         if(res != 0) {
diff --git a/daemon/usb.h b/daemon/usb.h
index 7e20dce..9b2cb1a 100644
--- a/daemon/usb.h
+++ b/daemon/usb.h
@@ -57,6 +57,8 @@ uint16_t usb_get_pid(struct usb_device *dev);
 void usb_get_fds(struct fdlist *list);
 int usb_get_timeout(void);
 int usb_send(struct usb_device *dev, const unsigned char *buf, int length);
+int usb_discover(void);
+void usb_autodiscover(int enable);
 int usb_process(void);
 int usb_process_timeout(int msec);