Updated usbmuxd protocol definition and public header.

[Hector] Merged by putting utils.c into a common dir,
avoiding log.c dependency for libusbmuxd, adding CMake
magic to tie things up.

4 files changed, 372 insertions, 84 deletions

diff --git a/libusbmuxd/CMakeLists.txt b/libusbmuxd/CMakeLists.txt
index 61de1a8..7f7b35f 100644
--- a/libusbmuxd/CMakeLists.txt
+++ b/libusbmuxd/CMakeLists.txt
@@ -1,4 +1,6 @@
-add_library (libusbmuxd libusbmuxd.c sock_stuff.c)
+include_directories (${CMAKE_SOURCE_DIR}/common)
+
+add_library (libusbmuxd libusbmuxd.c sock_stuff.c ../common/utils.c)
 
 # 'lib' is a UNIXism, the proper CMake target is usbmuxd
 # But we can't use that due to the conflict with the usbmuxd daemon,
diff --git a/libusbmuxd/libusbmuxd.c b/libusbmuxd/libusbmuxd.c
index 090695f..6a54765 100644
--- a/libusbmuxd/libusbmuxd.c
+++ b/libusbmuxd/libusbmuxd.c
@@ -6,6 +6,7 @@
 #include <sys/socket.h>
 #include <arpa/inet.h>
 #include <unistd.h>
+#include <signal.h>
 
 // usbmuxd public interface
 #include "usbmuxd.h"
@@ -13,10 +14,48 @@
 #include "usbmuxd-proto.h"
 // socket utility functions
 #include "sock_stuff.h"
+// misc utility functions
+#include "utils.h"
 
+static struct collection devices;
+static usbmuxd_event_cb_t event_cb = NULL;
+pthread_t devmon;
+static int listenfd = -1;
+
+/**
+ * Finds a device info record by its handle.
+ * if the record is not found, NULL is returned.
+ */
+static usbmuxd_device_info_t *devices_find(int handle)
+{
+	FOREACH(usbmuxd_device_info_t *dev, &devices) {
+		if (dev && dev->handle == handle) {
+			return dev;
+		}
+	} ENDFOREACH
+	return NULL;
+}
+
+/**
+ * Creates a socket connection to usbmuxd.
+ * For Mac/Linux it is a unix domain socket,
+ * for Windows it is a tcp socket.
+ */
+static int connect_usbmuxd_socket()
+{
+#ifdef WINDOWS
+	return connect_socket("127.0.0.1", 27015);
+#else
+	return connect_unix_socket(USBMUXD_SOCKET_FILE);
+#endif
+}
+
+/**
+ * Retrieves the result code to a previously sent request.
+ */
 static int usbmuxd_get_result(int sfd, uint32_t tag, uint32_t * result)
 {
-	struct usbmuxd_result res;
+	struct usbmuxd_result_msg res;
 	int recv_len;
 
 	if (!result) {
@@ -29,8 +68,8 @@ static int usbmuxd_get_result(int sfd, uint32_t tag, uint32_t * result)
 	} else {
 		if ((recv_len == sizeof(res))
 			&& (res.header.length == (uint32_t) recv_len)
-			&& (res.header.reserved == 0)
-			&& (res.header.type == USBMUXD_RESULT)
+			&& (res.header.version == USBMUXD_PROTOCOL_VERSION)
+			&& (res.header.message == MESSAGE_RESULT)
 			) {
 			*result = res.result;
 			if (res.header.tag == tag) {
@@ -44,16 +83,229 @@ static int usbmuxd_get_result(int sfd, uint32_t tag, uint32_t * result)
 	return -1;
 }
 
-int usbmuxd_scan(usbmuxd_scan_result ** available_devices)
+/**
+ * Generates an event, i.e. calls the callback function.
+ * A reference to a populated usbmuxd_event_t with information about the event
+ * and the corresponding device will be passed to the callback function.
+ */
+static void generate_event(usbmuxd_event_cb_t callback, const usbmuxd_device_info_t *dev, enum usbmuxd_device_event event)
+{
+	usbmuxd_event_t ev;
+
+	if (!callback || !dev) {
+		return;
+	}
+
+	ev.event = event;
+	memcpy(&ev.device, dev, sizeof(usbmuxd_device_info_t));
+
+	printf("%s: event=%d, handle=%d\n", __func__, ev.event, ev.device.handle);
+
+	callback(&ev);
+}
+
+/**
+ * Tries to connect to usbmuxd and wait if it is not running.
+ * 
+ * TODO inotify support should come here
+ */
+static int usbmuxd_listen()
 {
-	struct usbmuxd_scan_request s_req;
 	int sfd;
-	int scan_success = 0;
+	uint32_t res = -1;
+	struct usbmuxd_listen_request req;
+	struct usbmuxd_header hdr;
+
+	req.header.length = sizeof(struct usbmuxd_listen_request);
+	req.header.version = USBMUXD_PROTOCOL_VERSION;
+	req.header.message = MESSAGE_LISTEN;
+	req.header.tag = 2;
+
+	sfd = connect_usbmuxd_socket();
+	if (sfd < 0) {
+		fprintf(stderr, "DEBUG: waiting for usbmuxd to come up.\n");
+
+		while (event_cb) {
+			if ((sfd = connect_usbmuxd_socket()) > 0) {
+				fprintf(stderr, "DEBUG: usbmuxd started\n");
+				break;
+			}
+			sleep(1);
+		}
+	}
+
+	if (sfd < 0) {
+		fprintf(stderr, "ERROR: usbmuxd was supposed to be running here...\n");
+		return sfd;
+	}
+
+	if (send_buf(sfd, &req, req.header.length) != (int)req.header.length) {
+		fprintf(stderr, "ERROR: could not send listen packet\n");
+		close(sfd);
+		return -1;
+	}
+	if (usbmuxd_get_result(sfd, req.header.tag, &res) && (res != 0)) {
+		fprintf(stderr, "ERROR: did not get OK\n");
+		close(sfd);
+		return -1;
+	}
+
+	return sfd;
+}
+
+/**
+ * Waits for an event to occur, i.e. a packet coming from usbmuxd.
+ * Calls generate_event to pass the event via callback to the client program.
+ */
+int get_next_event(int sfd, usbmuxd_event_cb_t callback)
+{
+	int recv_len;
+	struct usbmuxd_listen_request req;
+	struct usbmuxd_header hdr;
+
+	/* block until we receive something */
+	recv_len = recv_buf_timeout(sfd, &hdr, sizeof(hdr), 0, 0);
+	if (recv_len < 0) {
+		int i;
+		fprintf(stderr, "DEBUG: connection closed.\n");
+		// when then usbmuxd connection fails,
+		// generate remove events for every device that
+		// is still present so applications know about it
+		// TODO: is this behaviour correct?
+		FOREACH(usbmuxd_device_info_t *dev, &devices) {
+			generate_event(callback, dev, UE_DEVICE_REMOVE);
+		} ENDFOREACH
+		collection_free(&devices);
+		return recv_len;
+	} else if (recv_len == sizeof(hdr)) {
+		if (hdr.message == MESSAGE_DEVICE_ADD) {
+			struct usbmuxd_device_record dev;
+			usbmuxd_device_info_t *devinfo = (usbmuxd_device_info_t*)malloc(sizeof(usbmuxd_device_info_t));
+			if (!devinfo) {
+				fprintf(stderr, "Out of memory!\n");
+				return -1;
+			}
+
+			if (hdr.length != sizeof(struct usbmuxd_header)+sizeof(struct usbmuxd_device_record)) {
+				fprintf(stderr, "WARNING: unexpected packet size%d for MESSAGE_DEVICE_ADD (expected %d)!\n", hdr.length, sizeof(struct usbmuxd_header)+sizeof(struct usbmuxd_device_record));
+			}
+			recv_len =  recv_buf_timeout(sfd, &dev, hdr.length - sizeof(struct usbmuxd_header), 0, 5000);
+			if (recv_len != (hdr.length - sizeof(struct usbmuxd_header))) {
+				fprintf(stderr, "Could not receive packet\n");
+				return recv_len;
+			}
+
+			devinfo->handle = dev.device_id;
+			devinfo->product_id = dev.product_id;
+			memset(devinfo->uuid, '\0', sizeof(devinfo->uuid));
+			memcpy(devinfo->uuid, dev.serial_number, sizeof(devinfo->uuid));
+
+			collection_add(&devices, devinfo);
+			generate_event(callback, devinfo, UE_DEVICE_ADD);
+		} else if (hdr.message == MESSAGE_DEVICE_REMOVE) {
+			uint32_t handle;
+			usbmuxd_device_info_t *dev;
+
+			if (hdr.length != sizeof(struct usbmuxd_header)+sizeof(uint32_t)) {
+				fprintf(stderr, "WARNING: unexpected packet size%d for MESSAGE_DEVICE_REMOVE (expected %d)!\n", hdr.length, sizeof(struct usbmuxd_header)+sizeof(uint32_t));
+			}
+			recv_len = recv_buf_timeout(sfd, &handle, sizeof(uint32_t), 0, 5000);
+			if (recv_len != sizeof(uint32_t)) {
+				fprintf(stderr, "Could not receive packet\n");
+				return recv_len;
+			}
+
+			dev = devices_find(handle);
+			if (!dev) {
+				fprintf(stderr, "WARNING: got device remove message for handle %d, but couldn't find the corresponding handle in the device list. This event will be ignored.\n", handle);
+			} else {
+				generate_event(callback, dev, UE_DEVICE_REMOVE);
+				collection_remove(&devices, dev);
+			}
+		} else {
+			fprintf(stderr, "%s: Unknown message type %d length %d\n", __func__, hdr.message, hdr.length);
+		}
+	} else {
+		fprintf(stderr, "%s: ERROR: incomplete packet received!\n", __func__);
+	}
+	return 0;
+}
+
+/**
+ * Device Monitor thread function.
+ *
+ * This function sets up a connection to usbmuxd
+ */
+static void *device_monitor(void *data)
+{
+	collection_init(&devices);
+
+	while (event_cb) {
+
+		listenfd = usbmuxd_listen();
+		if (listenfd < 0) {
+			fprintf(stderr, "DEBUG: listenfd=%d\n", listenfd);
+			continue;
+		}
+
+		while (event_cb) {
+			printf("waiting for events\n");
+			int res = get_next_event(listenfd, event_cb);
+			if (res < 0) {
+			    fprintf(stderr, "%s: closing connection (code %d)\n", __func__, res);
+			    break;
+			}
+		}
+	}
+
+	collection_free(&devices);
+	printf("%s: terminated\n", __func__);
+
+	return NULL;
+}
+
+int usbmuxd_subscribe(usbmuxd_event_cb_t callback)
+{
+	int res;
+
+	if (!callback) {
+		return -EINVAL;
+	}
+	event_cb = callback;
+
+	res = pthread_create(&devmon, NULL, device_monitor, NULL);
+	if (res != 0) {
+		fprintf(stderr, "ERROR: Could not start device watcher thread!\n");
+		return res;
+	}
+	return 0;
+}
+
+int usbmuxd_unsubscribe()
+{
+	event_cb = NULL;
+
+	if (pthread_kill(devmon, 0) == 0) {
+		printf("%s: unsubscribing callback\n", __func__);
+		close(listenfd);
+		listenfd = -1;
+		pthread_kill(devmon, SIGINT);
+		pthread_join(devmon, NULL);
+	}
+
+	return 0;
+}
+
+int usbmuxd_scan(usbmuxd_device_info_t ** available_devices)
+{
+	struct usbmuxd_listen_request s_req;
+	int sfd;
+	int listen_success = 0;
 	uint32_t res;
-	uint32_t pktlen;
 	int recv_len;
-	usbmuxd_scan_result *newlist = NULL;
-	struct usbmuxd_device_info_record dev_info_pkt;
+	usbmuxd_device_info_t *newlist = NULL;
+	struct usbmuxd_header hdr;
+	struct usbmuxd_device_record dev_info;
 	int dev_cnt = 0;
 
 	sfd = connect_unix_socket(USBMUXD_SOCKET_FILE);
@@ -62,9 +314,9 @@ int usbmuxd_scan(usbmuxd_scan_result ** available_devices)
 		return sfd;
 	}
 
-	s_req.header.length = sizeof(struct usbmuxd_scan_request);
-	s_req.header.reserved = 0;
-	s_req.header.type = USBMUXD_SCAN;
+	s_req.header.length = sizeof(struct usbmuxd_listen_request);
+	s_req.header.version = USBMUXD_PROTOCOL_VERSION;
+	s_req.header.message = MESSAGE_LISTEN;
 	s_req.header.tag = 2;
 
 	// send scan request packet
@@ -73,7 +325,7 @@ int usbmuxd_scan(usbmuxd_scan_result ** available_devices)
 		res = -1;
 		// get response
 		if (usbmuxd_get_result(sfd, s_req.header.tag, &res) && (res == 0)) {
-			scan_success = 1;
+			listen_success = 1;
 		} else {
 			fprintf(stderr,
 					"%s: Did not get response to scan request (with result=0)...\n",
@@ -83,50 +335,44 @@ int usbmuxd_scan(usbmuxd_scan_result ** available_devices)
 		}
 	}
 
-	if (!scan_success) {
-		fprintf(stderr, "%s: Could not send scan request!\n", __func__);
+	if (!listen_success) {
+		fprintf(stderr, "%s: Could not send listen request!\n", __func__);
 		return -1;
 	}
 
 	*available_devices = NULL;
 	// receive device list
 	while (1) {
-		if (recv_buf_timeout(sfd, &pktlen, 4, MSG_PEEK, 1000) == 4) {
-			if (pktlen != sizeof(dev_info_pkt)) {
+		if (recv_buf_timeout(sfd, &hdr, sizeof(hdr), 0, 1000) == sizeof(hdr)) {
+			if (hdr.length != sizeof(hdr)+sizeof(dev_info)) {
 				// invalid packet size received!
 				fprintf(stderr,
 						"%s: Invalid packet size (%d) received when expecting a device info record.\n",
-						__func__, pktlen);
+						__func__, hdr.length);
 				break;
 			}
 
-			recv_len = recv_buf(sfd, &dev_info_pkt, pktlen);
+			recv_len = recv_buf(sfd, &dev_info, hdr.length - sizeof(hdr));
 			if (recv_len <= 0) {
 				fprintf(stderr,
 						"%s: Error when receiving device info record\n",
 						__func__);
 				break;
-			} else if ((uint32_t) recv_len < pktlen) {
+			} else if ((uint32_t) recv_len < hdr.length - sizeof(hdr)) {
 				fprintf(stderr,
-						"%s: received less data than specified in header!\n",
-						__func__);
+						"%s: received less data than specified in header!\n", __func__);
 			} else {
-				//fprintf(stderr, "%s: got device record with id %d, UUID=%s\n", __func__, dev_info_pkt.device_info.device_id, dev_info_pkt.device_info.serial_number);
-				newlist =
-					(usbmuxd_scan_result *) realloc(*available_devices,
-													sizeof
-													(usbmuxd_scan_result) *
-													(dev_cnt + 1));
+				newlist = (usbmuxd_device_info_t *) realloc(*available_devices, sizeof(usbmuxd_device_info_t) * (dev_cnt + 1));
 				if (newlist) {
 					newlist[dev_cnt].handle =
-						(int) dev_info_pkt.device.device_id;
+						(int) dev_info.device_id;
 					newlist[dev_cnt].product_id =
-						dev_info_pkt.device.product_id;
-					memset(newlist[dev_cnt].serial_number, '\0',
-						   sizeof(newlist[dev_cnt].serial_number));
-					memcpy(newlist[dev_cnt].serial_number,
-						   dev_info_pkt.device.serial_number,
-						   sizeof(dev_info_pkt.device.serial_number));
+						dev_info.product_id;
+					memset(newlist[dev_cnt].uuid, '\0',
+						   sizeof(newlist[dev_cnt].uuid));
+					memcpy(newlist[dev_cnt].uuid,
+						   dev_info.serial_number,
+						   sizeof(newlist[dev_cnt].uuid));
 					*available_devices = newlist;
 					dev_cnt++;
 				} else {
@@ -144,24 +390,21 @@ int usbmuxd_scan(usbmuxd_scan_result ** available_devices)
 	}
 
 	// terminating zero record
-	newlist =
-		(usbmuxd_scan_result *) realloc(*available_devices,
-										sizeof(usbmuxd_scan_result) *
-										(dev_cnt + 1));
-	memset(newlist + dev_cnt, 0, sizeof(usbmuxd_scan_result));
+	newlist = (usbmuxd_device_info_t*) realloc(*available_devices, sizeof(usbmuxd_device_info_t) * (dev_cnt + 1));
+	memset(newlist + dev_cnt, 0, sizeof(usbmuxd_device_info_t));
 	*available_devices = newlist;
 
 	return dev_cnt;
 }
 
-int usbmuxd_connect(const int handle, const unsigned short tcp_port)
+int usbmuxd_connect(const int handle, const unsigned short port)
 {
 	int sfd;
 	struct usbmuxd_connect_request c_req;
 	int connected = 0;
 	uint32_t res = -1;
 
-	sfd = connect_unix_socket(USBMUXD_SOCKET_FILE);
+	sfd = connect_usbmuxd_socket();
 	if (sfd < 0) {
 		fprintf(stderr, "%s: Error: Connection to usbmuxd failed: %s\n",
 				__func__, strerror(errno));
@@ -169,11 +412,11 @@ int usbmuxd_connect(const int handle, const unsigned short tcp_port)
 	}
 
 	c_req.header.length = sizeof(c_req);
-	c_req.header.reserved = 0;
-	c_req.header.type = USBMUXD_CONNECT;
+	c_req.header.version = USBMUXD_PROTOCOL_VERSION;
+	c_req.header.message = MESSAGE_CONNECT;
 	c_req.header.tag = 3;
 	c_req.device_id = (uint32_t) handle;
-	c_req.tcp_dport = htons(tcp_port);
+	c_req.port = htons(port);
 	c_req.reserved = 0;
 
 	if (send_buf(sfd, &c_req, sizeof(c_req)) < 0) {
diff --git a/libusbmuxd/usbmuxd-proto.h b/libusbmuxd/usbmuxd-proto.h
index 7f8c2d6..1ecb7bc 100644
--- a/libusbmuxd/usbmuxd-proto.h
+++ b/libusbmuxd/usbmuxd-proto.h
@@ -1,52 +1,62 @@
 /* Protocol defintion for usbmuxd proxy protocol */
-
 #ifndef __USBMUXD_PROTO_H
 #define __USBMUXD_PROTO_H
 
 #include <stdint.h>
+#define USBMUXD_PROTOCOL_VERSION 0
 
 #define USBMUXD_SOCKET_FILE "/var/run/usbmuxd"
 
+enum usbmuxd_result {
+	RESULT_OK = 0,
+	RESULT_BADCOMMAND = 1,
+	RESULT_BADDEV = 2,
+	RESULT_CONNREFUSED = 3,
+	// ???
+	// ???
+	RESULT_BADVERSION = 6,
+};
+
+enum usbmuxd_msgtype {
+	MESSAGE_RESULT  = 1,
+	MESSAGE_CONNECT = 2,
+	MESSAGE_LISTEN = 3,
+	MESSAGE_DEVICE_ADD = 4,
+	MESSAGE_DEVICE_REMOVE = 5,
+	//???
+	//???
+	//MESSAGE_PLIST = 8,
+};
+
 struct usbmuxd_header {
 	uint32_t length;    // length of message, including header
-	uint32_t reserved;  // always zero
-	uint32_t type;      // message type
+	uint32_t version;   // protocol version
+	uint32_t message;   // message type
 	uint32_t tag;       // responses to this query will echo back this tag
 } __attribute__((__packed__));
 
-struct usbmuxd_result {
+struct usbmuxd_result_msg {
 	struct usbmuxd_header header;
 	uint32_t result;
 } __attribute__((__packed__));
 
-struct	usbmuxd_connect_request {
+struct usbmuxd_connect_request {
 	struct usbmuxd_header header;
 	uint32_t device_id;
-	uint16_t tcp_dport;   // TCP port number
+	uint16_t port;   // TCP port number
 	uint16_t reserved;   // set to zero
 } __attribute__((__packed__));
 
-struct usbmuxd_device {
-	uint32_t device_id;
-	uint16_t product_id;
-	char serial_number[40];
-} __attribute__((__packed__));
-
-struct usbmuxd_device_info_record {
+struct usbmuxd_listen_request {
 	struct usbmuxd_header header;
-	struct usbmuxd_device device;
-	char padding[222];
 } __attribute__((__packed__));
 
-struct usbmuxd_scan_request {
-	struct usbmuxd_header header;
+struct usbmuxd_device_record {
+	uint32_t device_id;
+	uint16_t product_id;
+	char serial_number[256];
+	uint16_t padding;
+	uint32_t location;
 } __attribute__((__packed__));
 
-enum {
-	USBMUXD_RESULT  = 1,
-	USBMUXD_CONNECT = 2,
-	USBMUXD_SCAN = 3,
-	USBMUXD_DEVICE_INFO = 4,
-};
-
 #endif /* __USBMUXD_PROTO_H */
diff --git a/libusbmuxd/usbmuxd.h b/libusbmuxd/usbmuxd.h
index ba45ec3..f12ae39 100644
--- a/libusbmuxd/usbmuxd.h
+++ b/libusbmuxd/usbmuxd.h
@@ -2,10 +2,7 @@
 #define __USBMUXD_H
 
 /**
- * Array entry returned by 'usbmuxd_scan()' scanning.
- *
- * If more than one device is available, 'product_id' and
- * 'serial_number' and be analysed to help make a selection.
+ * Device information structure holding data to identify the device.
  * The relevant 'handle' should be passed to 'usbmuxd_connect()', to
  * start a proxy connection.  The value 'handle' should be considered
  * opaque and no presumption made about the meaning of its value.
@@ -13,22 +10,58 @@
 typedef struct {
 	int handle;
 	int product_id;
-	char serial_number[41];
-} usbmuxd_scan_result;
+	char uuid[41];
+} usbmuxd_device_info_t;
+
+/**
+ * event types for event callback function
+ */
+enum usbmuxd_device_event {
+    UE_DEVICE_ADD = 1,
+    UE_DEVICE_REMOVE
+};
+
+/**
+ * Event structure that will be passed to the callback function.
+ * 'event' will contains the type of the event, and 'device' will contains
+ * information about the device.
+ */
+typedef struct {
+    int event;
+    usbmuxd_device_info_t device;
+} usbmuxd_event_t;
+
+/**
+ * Callback function prototype.
+ */
+typedef void (*usbmuxd_event_cb_t) (const usbmuxd_event_t *event);
+
+/**
+ * Subscribe a callback function so that applications get to know about
+ * device add/remove events.
+ *
+ * @param callback A callback function that is executed when an event occurs.
+ *
+ * @return 0 on success or negative on error.
+ */
+int usbmuxd_subscribe(usbmuxd_event_cb_t callback);
+
+/**
+ * Unsubscribe callback.
+ *
+ * @return only 0 for now.
+ */
+int usbmuxd_unsubscribe();
 
 /**
- * Contacts usbmuxd and performs a scan for connected devices.
+ * Contacts usbmuxd and retrieves a list of connected devices.
  *
- * @param available_devices pointer to array of usbmuxd_scan_result.
- * 	Array of available devices.  The required 'handle'
- *	should be passed to 'usbmuxd_connect()'.  The returned array
- *	is zero-terminated for convenience; the final (unused)
- *	entry containing handle == 0.  The returned array pointer
- *	should be freed by passing to 'free()' after use.
+ * @param available_devices pointer to an array of usbmuxd_device_info_t
+ *      that will hold records of the connected devices.
  *
  * @return number of available devices, zero on no devices, or negative on error
  */
-int usbmuxd_scan(usbmuxd_scan_result **available_devices);
+int usbmuxd_scan(usbmuxd_device_info_t **available_devices);
 
 /**
  * Request proxy connect to