From e855c861acde634662957131bbfb367260f8daf0 Mon Sep 17 00:00:00 2001
From: Hector Martin
Date: Sat, 10 Oct 2009 16:01:26 +0200
Subject: Disable polling in udev mode, use udev to signal device discovery

---
 daemon/main.c      | 58 ++++++++++++++++++++++++++++++++++++++++--------------
 daemon/usb-linux.c | 12 ++++++++++-
 daemon/usb.h       |  2 ++
 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);
 
-- 
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