preflight: check for device record before trying to read host id

3 files changed, 47 insertions, 11 deletions

diff --git a/src/conf.c b/src/conf.c
index 780a7c4..2291671 100644
--- a/src/conf.c
+++ b/src/conf.c
@@ -326,6 +326,35 @@ static int config_set_system_buid(const char *system_buid)
 }
 
 /**
+ * Determines whether a pairing record is present for the given device.
+ *
+ * @param udid The device UDID as given by the device.
+ *
+ * @return 1 if there's a pairing record for the given udid or 0 otherwise.
+ */
+int config_has_device_record(const char *udid)
+{
+	int res = 0;
+	if (!udid) return 0;
+
+	/* ensure config directory exists */
+	config_create_config_dir();
+
+	/* build file path */
+	const char *config_path = config_get_config_dir();
+	char *device_record_file = string_concat(config_path, DIR_SEP_S, udid, CONFIG_EXT, NULL);
+
+	struct stat st;
+
+	if ((stat(device_record_file, &st) == 0) && S_ISREG(st.st_mode))
+		res = 1;
+
+	free(device_record_file);
+
+	return res;
+}
+
+/**
  * Reads the BUID from a previously generated configuration file.
  *
  * @param system_buid pointer to a variable that will be set to point to a
@@ -430,7 +459,8 @@ int config_get_device_record(const char *udid, char **record_data, uint64_t *rec
 	char *device_record_file = string_concat(config_path, DIR_SEP_S, udid, CONFIG_EXT, NULL);
 
 	/* read file */
-	buffer_read_from_filename(device_record_file, record_data, record_size);	if (!*record_data) {
+	buffer_read_from_filename(device_record_file, record_data, record_size);
+	if (!*record_data) {
 		usbmuxd_log(LL_ERROR, "%s: failed to read '%s': %s", __func__, device_record_file, strerror(errno));
 		res = -ENOENT;
 	}
diff --git a/src/conf.h b/src/conf.h
index a104185..fd74607 100644
--- a/src/conf.h
+++ b/src/conf.h
@@ -31,6 +31,7 @@ const char *config_get_config_dir();
 
 void config_get_system_buid(char **system_buid);
 
+int config_has_device_record(const char *udid);
 int config_get_device_record(const char *udid, char **record_data, uint64_t *record_size);
 int config_set_device_record(const char *udid, char* record_data, uint64_t record_size);
 int config_remove_device_record(const char *udid);
diff --git a/src/preflight.c b/src/preflight.c
index b011344..5198d8c 100644
--- a/src/preflight.c
+++ b/src/preflight.c
@@ -161,17 +161,22 @@ retry:
 
 	int is_device_paired = 0;
 	char *host_id = NULL;
-	config_device_record_get_host_id(dev->udid, &host_id);
-	lerr = lockdownd_start_session(lockdown, host_id, NULL, NULL);
-	free(host_id);
-	if (lerr == LOCKDOWN_E_SUCCESS) {
-		usbmuxd_log(LL_INFO, "%s: StartSession success for device %s", __func__, _dev->udid);
-		usbmuxd_log(LL_INFO, "%s: Finished preflight on device %s", __func__, _dev->udid);
-		client_device_add(info);
-		goto leave;
-	}
+	if (config_has_device_record(dev->udid)) {
+		config_device_record_get_host_id(dev->udid, &host_id);
+		lerr = lockdownd_start_session(lockdown, host_id, NULL, NULL);
+		if (host_id)
+			free(host_id);
+		if (lerr == LOCKDOWN_E_SUCCESS) {
+			usbmuxd_log(LL_INFO, "%s: StartSession success for device %s", __func__, _dev->udid);
+			usbmuxd_log(LL_INFO, "%s: Finished preflight on device %s", __func__, _dev->udid);
+			client_device_add(info);
+			goto leave;
+		}
 
-	usbmuxd_log(LL_INFO, "%s: StartSession failed on device %s, lockdown error %d", __func__, _dev->udid, lerr);
+		usbmuxd_log(LL_INFO, "%s: StartSession failed on device %s, lockdown error %d", __func__, _dev->udid, lerr);
+	} else {
+		lerr = LOCKDOWN_E_INVALID_HOST_ID;
+	}
 	switch (lerr) {
 	case LOCKDOWN_E_INVALID_HOST_ID:
 		usbmuxd_log(LL_INFO, "%s: Device %s is not paired with this host.", __func__, _dev->udid);