usb_device_detection+main: Added hooks on basestation state change

A script will now run whenever the basesation is plugged/unplugged.

main.c

@@ -1,5 +1,10 @@
+// This is for asprintf support.
+// TODO: Don't use asprintf and remove this.
+#define _GNU_SOURCE
+
 #include <stdio.h>
 #include <stdlib.h>
+#include <unistd.h>
 
 #include <libusb-1.0/libusb.h>
 
@@ -21,6 +26,77 @@ static char const* const DEFAULT_MOTION_SENSOR =
 static uint16_t const BASESTATION_VENDOR_ID  = 0x048d;
 static uint16_t const BASESTATION_PRODUCT_ID = 0x8911;
 
+static char* get_hook_path(char const* const hook_name)
+{
+	char* path;
+	char* xdg_config_dir = getenv("XDG_CONFIG_HOME");
+	if (xdg_config_dir)
+		asprintf(&path, "%s/miix-wlr/hooks/%s-hook", xdg_config_dir, hook_name);
+	else
+		asprintf(&path,
+		         "%s/.config/miix-wlr/hooks/%s-hook",
+		         getenv("HOME"),
+		         hook_name);
+	return path;
+}
+
+static void on_basestation_connected()
+{
+	printf("Basestation connected\n");
+
+	char* hook_path = get_hook_path("basestation-connected");
+
+	if (access(hook_path, X_OK) != 0) {
+		fprintf(stderr, "Couldn't read or execute hook at %s\n", hook_path);
+		free(hook_path);
+		return;
+	}
+
+	pid_t pid = fork();
+
+	if (pid < 0) {
+		// Error
+		fprintf(stderr, "Unable to run hook script!\n");
+		perror("fork");
+	} else if (pid == 0) {
+		// In the child
+		char* argv[] = {hook_path, 0};
+		execve(hook_path, argv, environ);
+		exit(-1);
+	} else {
+		free(hook_path);
+	}
+}
+
+static void on_basestation_disconnected()
+{
+	printf("Basestation disconnected\n");
+
+	char* hook_path = get_hook_path("basestation-disconnected");
+
+	if (access(hook_path, X_OK) != 0) {
+		// Hook is innaccessible
+		fprintf(stderr, "Couldn't read or execute hook at %s\n", hook_path);
+		free(hook_path);
+		return;
+	}
+
+	pid_t pid = fork();
+
+	if (pid < 0) {
+		// Error
+		fprintf(stderr, "Unable to run hook script!\n");
+		perror("fork");
+	} else if (pid == 0) {
+		// In the child
+		char* argv[] = {hook_path, 0};
+		execve(hook_path, argv, environ);
+		exit(-1);
+	} else {
+		free(hook_path);
+	}
+}
+
 static enum accel_rotation last_accel_rotation = ACCEL_ROTATION_NO_CHANGE;
 
 int main(int, char**)
@@ -35,6 +111,10 @@ int main(int, char**)
 	struct usb_detector* base_station_detector =
 	    create_detector(BASESTATION_VENDOR_ID, BASESTATION_PRODUCT_ID);
 
+	base_station_detector->on_connected          = &on_basestation_connected;
+	base_station_detector->on_disconnected       = &on_basestation_disconnected;
+	base_station_detector->has_hotplug_callbacks = true;
+
 	struct miix_wlr_state* state = miix_wlr_init();
 
 	for (;;) {

usb_device_detection.c

@@ -10,11 +10,13 @@ int hotplug_callback(struct libusb_context*,
 {
 	struct usb_detector* detector = user_data;
 
-	if (event == LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED)
+	if (event == LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED) {
 		detector->is_connected = true;
-	else if (event == LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT)
+		if (detector->has_hotplug_callbacks) detector->on_connected();
+	} else if (event == LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT) {
 		detector->is_connected = false;
-	else
+		if (detector->has_hotplug_callbacks) detector->on_disconnected();
+	} else
 		printf("Unexpected USB device event %d\n", event);
 
 	return 0;
@@ -49,6 +51,8 @@ struct usb_detector* create_detector(uint16_t vendor_id, uint16_t product_id)
 	detector->is_connected        = false;
 	detector->event_handler_should_exit = false;
 
+	detector->has_hotplug_callbacks = false;
+
 	if (libusb_hotplug_register_callback(detector->usb_context,
 	                                     LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED |
 	                                         LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT,

usb_device_detection.h

@@ -6,6 +6,8 @@
 
 #include <libusb-1.0/libusb.h>
 
+typedef void (*hotplug_callback_f)();
+
 struct usb_detector {
 	atomic_bool is_connected;
 
@@ -14,6 +16,10 @@ struct usb_detector {
 
 	struct libusb_context*         usb_context;
 	libusb_hotplug_callback_handle hotplug_handle;
+
+	atomic_bool        has_hotplug_callbacks;
+	hotplug_callback_f on_connected;
+	hotplug_callback_f on_disconnected;
 };
 
 struct usb_detector* create_detector(uint16_t vendor_id, uint16_t product_id);