Rename uinput backend to evdev

1 files changed, 484 insertions, 0 deletions

diff --git a/evdev.c b/evdev.c
new file mode 100644
index 0000000..1355c06
--- /dev/null
+++ b/evdev.c
@@ -0,0 +1,484 @@
+#include <linux/input.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <unistd.h>
+#include <linux/uinput.h>
+#include <sys/ioctl.h>
+
+#include "midimonster.h"
+#include "evdev.h"
+
+#define BACKEND_NAME "evdev"
+#define UINPUT_PATH "/dev/uinput"
+
+int init(){
+	backend evdev = {
+		.name = BACKEND_NAME,
+		.conf = evdev_configure,
+		.create = evdev_instance,
+		.conf_instance = evdev_configure_instance,
+		.channel = evdev_channel,
+		.handle = evdev_set,
+		.process = evdev_handle,
+		.start = evdev_start,
+		.shutdown = evdev_shutdown
+	};
+
+	if(mm_backend_register(evdev)){
+		fprintf(stderr, "Failed to register evdev backend\n");
+		return 1;
+	}
+
+	return 0;
+}
+
+static int evdev_configure(char* option, char* value) {
+	//intentionally ignored
+	return 0;
+}
+
+static int evdev_configure_instance(instance* inst, char* option, char* value) {
+	evdev_instance_data* data = (evdev_instance_data*) inst->impl;
+
+	if (!strcmp(option, "device")) {
+		if (data->device_path) {
+			free(data->device_path);
+		}
+		data->device_path = strdup(value);
+
+		if (!data->device_path) {
+			fprintf(stderr, "Failed to allocate memory for device path: %s\n", strerror(errno));
+			return 1;
+		}
+	} else if (!strcmp(option, "exclusive")) {
+		data->exclusive = strtoul(value, NULL, 10);
+	} else if (!strcmp(option, "name")) {
+		if (data->name) {
+			free(data->name);
+		}
+
+		data->name = strdup(value);
+
+		if (!data->name) {
+			fprintf(stderr, "Failed to allocate memory for name: %s\n", strerror(errno));
+			return 1;
+		}
+	} else {
+		fprintf(stderr, "Unkown configuration parameter %s for evdev backend\n", option);
+		return 1;
+	}
+	return 0;
+}
+
+static channel* evdev_channel(instance* inst, char* spec) {
+	evdev_instance_data* data = (evdev_instance_data*) inst->impl;
+	char* next = spec;
+	// type
+	unsigned long type = strtoul(spec, &next, 10);
+
+	if (spec == next) {
+		fprintf(stderr, "Cannot parse type\n");
+		return NULL;
+	}
+
+	if (type >= EV_MAX) {
+		fprintf(stderr, "Type is out of range\n");
+		return NULL;
+	}
+
+	if (next[0] != '.') {
+		fprintf(stderr, "Cannot parse code. Unknown character %c\n", next[0]);
+		return NULL;
+	}
+
+	spec = next + 1;
+
+	unsigned long code = strtoul(spec, &next, 10);
+
+	if (spec == next) {
+		fprintf(stderr, "Cannot parse code\n");
+		return NULL;
+	}
+
+	if (type == EV_SYN && code >= SYN_MAX) {
+		fprintf(stderr, "Code is out of range. Limit for SYN is %d\n", SYN_MAX);
+	} else if (type == EV_KEY && code >= KEY_MAX) {
+		fprintf(stderr, "Code is out of range. Limit for KEY is %d\n", KEY_MAX);
+		return NULL;
+	} else if (type == EV_REL && code >= REL_MAX) {
+		fprintf(stderr, "Code is out of range. Limit for REL is %d\n", REL_MAX);
+		return NULL;
+	} else if (type == EV_ABS && code >= ABS_MAX) {
+		fprintf(stderr, "Code is out of range. Limit for ABS is %d\n", ABS_MAX);
+		return NULL;
+	} else if (type == EV_SW && code >= SW_MAX) {
+		fprintf(stderr, "Code is out of range. Limit for SW is %d\n", SW_MAX);
+		return NULL;
+	} else if (type == EV_MSC && code >= MSC_MAX) {
+		fprintf(stderr, "Code is out of range. Limit for MSC is %d\n", MSC_MAX);
+		return NULL;
+	} else if (type == EV_LED && code >= LED_MAX) {
+		fprintf(stderr, "Code is out of range. Limit for LED is %d\n", LED_MAX);
+		return NULL;
+	} else if (type == EV_REP && code >= REP_MAX) {
+		fprintf(stderr, "Code is out of range. Limit for REP is %d\n", REP_MAX);
+		return NULL;
+	} else if (type == EV_SND && code >= SND_MAX) {
+		fprintf(stderr, "Code is out of range. Limit for SND is %d\n", SND_MAX);
+	}
+
+	uint64_t u;
+	if (next[0] == '.') {
+		spec = next + 1;
+		long value = strtol(spec, &next, 10);
+		if (spec == next) {
+			fprintf(stderr, "Cannot parse value\n");
+			return NULL;
+		}
+		if (type == EV_KEY && (value != 0 && value != 1)) {
+			fprintf(stderr, "Value of KEY %ld is out of range. Only values 0 and 1 are supported for KEY.\n", value);
+			return NULL;
+		}
+		// find event with value
+		for (u = 0; u < data->size_events; u++) {
+			if (data->events[u].type == type
+					&& data->events[u].code == code
+					&& data->events[u].value == value) {
+				break;
+			}
+		}
+	} else if (next[0] != '\0') {
+		fprintf(stderr, "Unkown characters: %s\n", next);
+		return NULL;
+	} else {
+		// find event
+		for (u = 0; u < data->size_events; u++) {
+			if (data->events[u].type == type
+					&& data->events[u].code == code) {
+				break;
+			}
+		}
+	}
+
+	// check if no event was found
+	if (u == data->size_events) {
+		fprintf(stderr, "Alloc dev %ld: %ld, %ld\n", u, type, code);
+		data->events = realloc(data->events, (u + 1) * sizeof(struct input_event));
+
+		if (!data->events) {
+			fprintf(stderr, "Failed to allocate memory\n");
+			return NULL;
+		}
+
+		data->events[u].type = (uint16_t) type;
+		data->events[u].code = (uint16_t) code;
+		data->size_events++;
+	}
+	return mm_channel(inst, u, 1);
+}
+
+static instance* evdev_instance() {
+	instance* inst = mm_instance();
+	if (!inst) {
+		return NULL;
+	}
+
+	inst->impl = calloc(1, sizeof(evdev_instance_data));
+	if (!inst->impl) {
+		fprintf(stderr, "Failed to allocate memory for instance\n");
+		return NULL;
+	}
+	return inst;
+}
+
+static channel_value evdev_normalize(evdev_instance_data* data, uint64_t ident, struct input_event* event) {
+	channel_value value = {};
+
+	switch (event->type) {
+		case EV_KEY:
+			value.normalised = event->value > 0;
+			break;
+		case EV_REL:
+			if (event->value > 0) {
+				value.normalised = 1.0;
+			} else {
+				value.normalised = 0.0;
+			}
+			break;
+	}
+
+	return value;
+}
+
+static uint32_t evdev_convert_normalised(struct input_event event, channel_value* value) {
+	switch (event.type) {
+		case EV_KEY:
+			return value->normalised < 0.5;
+		case EV_REL:
+			return (value->normalised < 0.5) - 1;
+		default:
+			return value->normalised < 0.5;
+	}
+}
+
+
+static int evdev_handle(size_t num, managed_fd* fds) {
+	struct input_event event;
+	ssize_t bytes = 0;
+	uint64_t ident;
+
+	evdev_instance_data* data;
+
+	channel* channel;
+	for (int i = 0; i < num; i++) {
+		bytes = read(fds[i].fd, &event, sizeof(struct input_event));
+
+		if (bytes < sizeof(struct input_event)) {
+			fprintf(stderr, "Failed to read an complete event\n");
+			return 1;
+		}
+		data = (evdev_instance_data*) fds[0].impl;
+		for (ident = 0; ident < data->size_events; ident++) {
+			if (data->events[ident].type == event.type
+					&& data->events[ident].code == event.code) {
+				break;
+			}
+		}
+		fprintf(stderr, "Found event: %d, %d, %d (%ld/%ld)\n", event.type, event.code, event.value, ident, data->size_events);
+
+		if (ident >= data->size_events) {
+			fprintf(stderr, "Event not registered.\n");
+			continue;
+		}
+		channel = mm_channel(mm_instance_find(BACKEND_NAME, data->ident), ident, 0);
+
+		if (channel) {
+			fprintf(stderr, "Channel found\n");
+			if (mm_channel_event(channel, evdev_normalize(data, ident, &event))) {
+				return 1;
+			}
+		}
+	}
+
+	return 0;
+}
+
+static int evdev_open_input_device(evdev_instance_data* data) {
+	if (!data->device_path) {
+		return 0;
+	}
+
+	data->fd_in = open(data->device_path, O_RDONLY | O_NONBLOCK);
+
+	if (data->fd_in < 0) {
+		fprintf(stderr, "Failed to open device %s: %s\n", data->device_path, strerror(errno));
+		return 1;
+	}
+	int grab = data->exclusive;
+	if (ioctl(data->fd_in, EVIOCGRAB, &grab) > 0) {
+		fprintf(stderr, "Cannot set exclusive lock on device %s\n", data->device_path);
+		close(data->fd_in);
+		data->fd_in = -1;
+		return 1;
+	}
+
+	if (!mm_manage_fd(data->fd_in, BACKEND_NAME, 1, data)) {
+		return 1;
+	}
+
+	return 0;
+}
+
+static int enable_device_keys(evdev_instance_data* data, int uinput_fd, struct uinput_user_dev* dev) {
+	unsigned int u;
+	int ret;
+	int action;
+	uint8_t first_bits[EV_CNT];
+	memset(first_bits, 0, EV_CNT * sizeof(uint8_t));
+	for (u = 0; u < data->size_events; u++) {
+		if (data->events[u].type < EV_MAX && !first_bits[data->events[u].type]) {
+			ret = ioctl(uinput_fd, UI_SET_EVBIT, data->events[u].type);
+
+			if (ret < 0) {
+				fprintf(stderr, "Cannot enable type: %d\n", data->events[u].type);
+				return 1;
+			}
+		}
+		switch (data->events[u].type) {
+			case EV_KEY:
+				action = UI_SET_KEYBIT;
+				break;
+			case EV_ABS:
+				action = UI_SET_ABSBIT;
+				break;
+			case EV_REL:
+				action = UI_SET_RELBIT;
+				break;
+			case EV_MSC:
+				action = UI_SET_MSCBIT;
+				break;
+			default:
+				fprintf(stderr, "Event code not supported: %d\n", data->events[u].type);
+				return 1;
+		}
+		ret = ioctl(uinput_fd,  action, data->events[u].code);
+
+		if (ret < 0) {
+			fprintf(stderr, "Cannot enable code: %d\n", data->events[u].code);
+			return 1;
+		}
+	}
+	return 0;
+}
+
+static int uinput_create_output_device(evdev_instance_data* data) {
+
+	int uinput_fd = open(UINPUT_PATH, O_WRONLY | O_NONBLOCK);
+
+	if (uinput_fd < 0) {
+		fprintf(stderr, "Cannot open uinput device: %s\n", strerror(errno));
+		return 1;
+	}
+
+	struct uinput_user_dev dev = {};
+	memset(&dev, 0, sizeof(dev));
+	strncpy(dev.name, data->name, UINPUT_MAX_NAME_SIZE - 1);
+	dev.id.bustype = 0;
+	dev.id.vendor = 0;
+	dev.id.product = 0;
+	dev.id.version = 0;
+
+	if (enable_device_keys(data, uinput_fd, &dev)) {
+		close(uinput_fd);
+		return 1;
+	}
+	// write config to uinput
+	int ret = write(uinput_fd, &dev, sizeof(dev));
+
+	if (ret < 0) {
+		fprintf(stderr, "Cannot write to uinput device: %s\n", strerror(errno));
+		close(uinput_fd);
+		return 1;
+	}
+
+	ret = ioctl(uinput_fd, UI_DEV_CREATE);
+
+	if (ret < 0) {
+		fprintf(stderr, "Cannot create device: %s\n", strerror(errno));
+		close(uinput_fd);
+		return 1;
+	}
+
+	data->fd_out = uinput_fd;
+
+	return 0;
+}
+
+static int evdev_start() {
+	size_t n;
+	instance** inst = NULL;
+	evdev_instance_data* data;
+	if (mm_backend_instances(BACKEND_NAME, &n, &inst)) {
+		fprintf(stderr, "Failed to fetch instance list\n");
+		return 1;
+	}
+
+	if (!n) {
+		free(inst);
+		return 0;
+	}
+
+	for (unsigned p = 0; p < n; p++) {
+		data = (evdev_instance_data*) inst[p]->impl;
+
+		if (data->name) {
+			uinput_create_output_device(data);
+		}
+
+		if (data->device_path) {
+			evdev_open_input_device(data);
+		}
+		data->ident = p;
+		inst[p]->ident = data->ident;
+	}
+
+	free(inst);
+	return 0;
+}
+
+static int evdev_set(instance* inst, size_t num, channel** c, channel_value* v) {
+	size_t u;
+	evdev_instance_data* data;
+	uint64_t ident;
+	int ret;
+	struct input_event event = {};
+
+	for (u = 0; u < num; u++) {
+		data = (evdev_instance_data*) c[u]->instance->impl;
+		ident = c[u]->ident;
+
+		memcpy(&event, &data->events[ident], sizeof(struct input_event));
+		event.value = evdev_convert_normalised(event, v);
+
+		ret = write(data->fd_out, &event, sizeof(event));
+		if (ret < 0 ) {
+			fprintf(stderr, "Cannot write event: %s\n", strerror(errno));
+			return 1;
+		}
+		event.type = EV_SYN;
+		event.code = SYN_REPORT;
+		event.value = 0;
+
+		ret = write(data->fd_out, &event, sizeof(event));
+		if (ret < 0) {
+			fprintf(stderr, "Cannot send SYN_REPORT event: %s\n", strerror(errno));
+			return 1;
+		}
+	}
+
+	return 0;
+}
+
+static int evdev_shutdown() {
+	evdev_instance_data* data = NULL;
+	instance** instances = NULL;
+	size_t n = 0;
+
+	if (mm_backend_instances(BACKEND_NAME, &n, &instances)) {
+		fprintf(stderr, "Failed to fetch instance list\n");
+		return 1;
+	}
+
+	if (!n) {
+		free(instances);
+		return 0;
+	}
+
+	for (unsigned p = 0; p < n; p++) {
+		data = (evdev_instance_data*) instances[p]->impl;
+		if (data->fd_in < 0) {
+			close(data->fd_in);
+			data->fd_in = -1;
+		}
+
+		if (data->fd_out < 0) {
+			int ret = ioctl(data->fd_out, UI_DEV_DESTROY);
+
+			if (ret < 0) {
+				fprintf(stderr, "Could not destroy device: %s\n", strerror(errno));
+				return 1;
+			}
+			close(data->fd_out);
+			data->fd_out = -1;
+		}
+
+		free(data->events);
+		free(data->name);
+		free(data->device_path);
+		free(data);
+	}
+	free(instances);
+	return 0;
+}