Initial implementation of seatd and libseat

common/connection.c

@@ -0,0 +1,312 @@
+#include <errno.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <unistd.h>
+
+#include "compiler.h"
+#include "connection.h"
+
+#define CLEN (CMSG_LEN(MAX_FDS_OUT * sizeof(int)))
+
+ALWAYS_INLINE static uint32_t connection_buffer_mask(const uint32_t idx) {
+	return idx & (CONNECTION_BUFFER_SIZE - 1);
+}
+
+ALWAYS_INLINE static uint32_t connection_buffer_size(const struct connection_buffer *b) {
+	return b->head - b->tail;
+}
+
+ALWAYS_INLINE static void connection_buffer_consume(struct connection_buffer *b, const size_t size) {
+	b->tail += size;
+}
+
+ALWAYS_INLINE static void connection_buffer_restore(struct connection_buffer *b, const size_t size) {
+	b->tail -= size;
+}
+
+/*
+ * connection_buffer_get_iov prepares I/O vectors pointing to our ring buffer.
+ * Two may be used if the buffer has wrapped around.
+ */
+static void connection_buffer_get_iov(struct connection_buffer *b, struct iovec *iov, int *count) {
+	uint32_t head = connection_buffer_mask(b->head);
+	uint32_t tail = connection_buffer_mask(b->tail);
+	if (tail < head) {
+		iov[0].iov_base = b->data + tail;
+		iov[0].iov_len = head - tail;
+		*count = 1;
+	} else if (head == 0) {
+		iov[0].iov_base = b->data + tail;
+		iov[0].iov_len = sizeof b->data - tail;
+		*count = 1;
+	} else {
+		iov[0].iov_base = b->data + tail;
+		iov[0].iov_len = sizeof b->data - tail;
+		iov[1].iov_base = b->data;
+		iov[1].iov_len = head;
+		*count = 2;
+	}
+}
+
+/*
+ * connection_buffer_put_iov prepares I/O vectors pointing to our ring buffer.
+ * Two may be used if the buffer has wrapped around.
+ */
+static void connection_buffer_put_iov(struct connection_buffer *b, struct iovec *iov, int *count) {
+	uint32_t head = connection_buffer_mask(b->head);
+	uint32_t tail = connection_buffer_mask(b->tail);
+	if (head < tail) {
+		iov[0].iov_base = b->data + head;
+		iov[0].iov_len = tail - head;
+		*count = 1;
+	} else if (tail == 0) {
+		iov[0].iov_base = b->data + head;
+		iov[0].iov_len = sizeof b->data - head;
+		*count = 1;
+	} else {
+		iov[0].iov_base = b->data + head;
+		iov[0].iov_len = sizeof b->data - head;
+		iov[1].iov_base = b->data;
+		iov[1].iov_len = tail;
+		*count = 2;
+	}
+}
+
+/*
+ * connection_buffer_copy copies from our ring buffer into a linear buffer.
+ */
+static void connection_buffer_copy(const struct connection_buffer *b, void *data, const size_t count) {
+	uint32_t tail = connection_buffer_mask(b->tail);
+	if (tail + count <= sizeof b->data) {
+		memcpy(data, b->data + tail, count);
+		return;
+	}
+
+	uint32_t size = sizeof b->data - tail;
+	memcpy(data, b->data + tail, size);
+	memcpy((char *)data + size, b->data, count - size);
+}
+/*
+ * connection_buffer_copy copies from a linear buffer into our ring buffer.
+ */
+static int connection_buffer_put(struct connection_buffer *b, const void *data, const size_t count) {
+	if (count > sizeof(b->data)) {
+		errno = EOVERFLOW;
+		return -1;
+	}
+
+	uint32_t head = connection_buffer_mask(b->head);
+	if (head + count <= sizeof b->data) {
+		memcpy(b->data + head, data, count);
+	} else {
+		uint32_t size = sizeof b->data - head;
+		memcpy(b->data + head, data, size);
+		memcpy(b->data, (const char *)data + size, count - size);
+	}
+
+	b->head += count;
+	return 0;
+}
+
+/*
+ * close_fds closes all fds within a connection_buffer
+ */
+static void connection_buffer_close_fds(struct connection_buffer *buffer) {
+	size_t size = connection_buffer_size(buffer);
+	if (size == 0) {
+		return;
+	}
+	int fds[sizeof(buffer->data) / sizeof(int)];
+	connection_buffer_copy(buffer, fds, size);
+	int count = size / sizeof fds[0];
+	size = count * sizeof fds[0];
+	for (int idx = 0; idx < count; idx++) {
+		close(fds[idx]);
+	}
+	connection_buffer_consume(buffer, size);
+}
+
+/*
+ * build_cmsg prepares a cmsg from a buffer full of fds
+ */
+static void build_cmsg(struct connection_buffer *buffer, char *data, int *clen) {
+	size_t size = connection_buffer_size(buffer);
+	if (size > MAX_FDS_OUT * sizeof(int)) {
+		size = MAX_FDS_OUT * sizeof(int);
+	}
+
+	if (size <= 0) {
+		*clen = 0;
+		return;
+	}
+
+	struct cmsghdr *cmsg = (struct cmsghdr *)data;
+	cmsg->cmsg_level = SOL_SOCKET;
+	cmsg->cmsg_type = SCM_RIGHTS;
+	cmsg->cmsg_len = CMSG_LEN(size);
+	connection_buffer_copy(buffer, CMSG_DATA(cmsg), size);
+	*clen = cmsg->cmsg_len;
+}
+
+static int decode_cmsg(struct connection_buffer *buffer, struct msghdr *msg) {
+	bool overflow = false;
+	struct cmsghdr *cmsg;
+	for (cmsg = CMSG_FIRSTHDR(msg); cmsg != NULL; cmsg = CMSG_NXTHDR(msg, cmsg)) {
+		if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
+			continue;
+		}
+
+		size_t size = cmsg->cmsg_len - CMSG_LEN(0);
+		size_t max = sizeof(buffer->data) - connection_buffer_size(buffer);
+		if (size > max || overflow) {
+			overflow = true;
+			size /= sizeof(int);
+			for (size_t idx = 0; idx < size; idx++) {
+				close(((int *)CMSG_DATA(cmsg))[idx]);
+			}
+		} else if (connection_buffer_put(buffer, CMSG_DATA(cmsg), size) < 0) {
+			return -1;
+		}
+	}
+
+	if (overflow) {
+		errno = EOVERFLOW;
+		return -1;
+	}
+	return 0;
+}
+
+int connection_read(struct connection *connection) {
+	if (connection_buffer_size(&connection->in) >= sizeof(connection->in.data)) {
+		errno = EOVERFLOW;
+		return -1;
+	}
+
+	int count;
+	struct iovec iov[2];
+	connection_buffer_put_iov(&connection->in, iov, &count);
+
+	char cmsg[CLEN];
+	struct msghdr msg = {
+		.msg_name = NULL,
+		.msg_namelen = 0,
+		.msg_iov = iov,
+		.msg_iovlen = count,
+		.msg_control = cmsg,
+		.msg_controllen = sizeof cmsg,
+		.msg_flags = 0,
+	};
+
+	int len;
+	do {
+		len = recvmsg(connection->fd, &msg, MSG_DONTWAIT | MSG_CMSG_CLOEXEC);
+		if (len == -1 && errno != EINTR)
+			return -1;
+	} while (len == -1);
+
+	if (decode_cmsg(&connection->fds_in, &msg) != 0) {
+		return -1;
+	}
+	connection->in.head += len;
+
+	return connection_buffer_size(&connection->in);
+}
+
+int connection_flush(struct connection *connection) {
+	if (!connection->want_flush) {
+		return 0;
+	}
+
+	uint32_t tail = connection->out.tail;
+	while (connection->out.head - connection->out.tail > 0) {
+		int count;
+		struct iovec iov[2];
+		connection_buffer_get_iov(&connection->out, iov, &count);
+
+		int clen;
+		char cmsg[CLEN];
+		build_cmsg(&connection->fds_out, cmsg, &clen);
+		struct msghdr msg = {
+			.msg_name = NULL,
+			.msg_namelen = 0,
+			.msg_iov = iov,
+			.msg_iovlen = count,
+			.msg_control = (clen > 0) ? cmsg : NULL,
+			.msg_controllen = clen,
+			.msg_flags = 0,
+		};
+
+		int len;
+		do {
+			len = sendmsg(connection->fd, &msg, MSG_NOSIGNAL | MSG_DONTWAIT);
+			if (len == -1 && errno != EINTR)
+				return -1;
+		} while (len == -1);
+		connection_buffer_close_fds(&connection->fds_out);
+		connection->out.tail += len;
+	}
+	connection->want_flush = 0;
+	return connection->out.head - tail;
+}
+
+int connection_put(struct connection *connection, const void *data, size_t count) {
+	if (connection_buffer_size(&connection->out) + count > CONNECTION_BUFFER_SIZE) {
+		connection->want_flush = 1;
+		if (connection_flush(connection) == -1) {
+			return -1;
+		}
+	}
+
+	if (connection_buffer_put(&connection->out, data, count) == -1) {
+		return -1;
+	}
+
+	connection->want_flush = 1;
+	return 0;
+}
+
+int connection_put_fd(struct connection *connection, int fd) {
+	if (connection_buffer_size(&connection->fds_out) == MAX_FDS_OUT * sizeof fd) {
+		errno = EOVERFLOW;
+		return -1;
+	}
+
+	return connection_buffer_put(&connection->fds_out, &fd, sizeof fd);
+}
+
+int connection_get(struct connection *connection, void *dst, size_t count) {
+	if (count > connection_buffer_size(&connection->in)) {
+		errno = EAGAIN;
+		return -1;
+	}
+	connection_buffer_copy(&connection->in, dst, count);
+	connection_buffer_consume(&connection->in, count);
+	return count;
+}
+
+int connection_get_fd(struct connection *connection) {
+	int fd;
+	if (sizeof fd > connection_buffer_size(&connection->fds_in)) {
+		errno = EAGAIN;
+		return -1;
+	}
+	connection_buffer_copy(&connection->fds_in, &fd, sizeof fd);
+	connection_buffer_consume(&connection->fds_in, sizeof fd);
+	return fd;
+}
+
+void connection_close_fds(struct connection *connection) {
+	connection_buffer_close_fds(&connection->fds_in);
+	connection_buffer_close_fds(&connection->fds_out);
+}
+
+size_t connection_pending(struct connection *connection) {
+	return connection_buffer_size(&connection->in);
+}
+
+void connection_restore(struct connection *connection, size_t count) {
+	connection_buffer_restore(&connection->in, count);
+}

common/drm.c

@@ -0,0 +1,23 @@
+#include <sys/ioctl.h>
+#include <sys/sysmacros.h>
+#include <sys/types.h>
+
+#include "drm.h"
+
+// From libdrm
+#define DRM_IOCTL_BASE	      'd'
+#define DRM_IO(nr)	      _IO(DRM_IOCTL_BASE, nr)
+#define DRM_IOCTL_SET_MASTER  DRM_IO(0x1e)
+#define DRM_IOCTL_DROP_MASTER DRM_IO(0x1f)
+
+int drm_set_master(int fd) {
+	return ioctl(fd, DRM_IOCTL_SET_MASTER, 0);
+}
+
+int drm_drop_master(int fd) {
+	return ioctl(fd, DRM_IOCTL_DROP_MASTER, 0);
+}
+
+int dev_is_drm(dev_t device) {
+	return major(device) == 226;
+}

common/evdev.c

@@ -0,0 +1,15 @@
+#include <linux/input.h>
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <sys/sysmacros.h>
+#include <sys/types.h>
+
+#include "evdev.h"
+
+int evdev_revoke(int fd) {
+	return ioctl(fd, EVIOCREVOKE, NULL);
+}
+
+int dev_is_evdev(dev_t device) {
+	return major(device) == 13;
+}

common/list.c

@@ -0,0 +1,76 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "list.h"
+
+void list_init(struct list *list) {
+	list->capacity = 10;
+	list->length = 0;
+	list->items = malloc(sizeof(void *) * list->capacity);
+}
+
+static void list_resize(struct list *list) {
+	if (list->length == list->capacity) {
+		list->capacity *= 2;
+		list->items = realloc(list->items, sizeof(void *) * list->capacity);
+	}
+}
+
+void list_free(struct list *list) {
+	list->capacity = 0;
+	list->length = 0;
+	free(list->items);
+}
+
+void list_add(struct list *list, void *item) {
+	list_resize(list);
+	list->items[list->length++] = item;
+}
+
+void list_insert(struct list *list, size_t index, void *item) {
+	list_resize(list);
+	memmove(&list->items[index + 1], &list->items[index],
+		sizeof(void *) * (list->length - index));
+	list->length++;
+	list->items[index] = item;
+}
+
+void list_del(struct list *list, size_t index) {
+	list->length--;
+	memmove(&list->items[index], &list->items[index + 1],
+		sizeof(void *) * (list->length - index));
+}
+
+size_t list_find(struct list *list, const void *item) {
+	for (size_t i = 0; i < list->length; i++) {
+		if (list->items[i] == item) {
+			return i;
+		}
+	}
+	return -1;
+}
+
+void list_concat(struct list *list, struct list *source) {
+	if (list->length + source->length > list->capacity) {
+		while (list->length + source->length > list->capacity) {
+			list->capacity *= 2;
+		}
+		list->items = realloc(list->items, sizeof(void *) * list->capacity);
+	}
+	memmove(&list->items[list->length], source->items, sizeof(void *) * (source->length));
+	list->length += source->length;
+}
+
+void list_truncate(struct list *list) {
+	list->length = 0;
+}
+
+void *list_pop_front(struct list *list) {
+	if (list->length == 0) {
+		return NULL;
+	}
+	void *item = list->items[0];
+	list_del(list, 0);
+	return item;
+}

common/log.c

@@ -0,0 +1,80 @@
+#include <errno.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <unistd.h>
+
+#include "log.h"
+
+const long NSEC_PER_SEC = 1000000000;
+
+static enum libseat_log_level current_log_level;
+static struct timespec start_time = {-1, -1};
+static bool colored = false;
+
+static const char *verbosity_colors[] = {
+	[LIBSEAT_SILENT] = "",
+	[LIBSEAT_ERROR] = "\x1B[1;31m",
+	[LIBSEAT_INFO] = "\x1B[1;34m",
+	[LIBSEAT_DEBUG] = "\x1B[1;90m",
+};
+
+static const char *verbosity_headers[] = {
+	[LIBSEAT_SILENT] = "",
+	[LIBSEAT_ERROR] = "[ERROR]",
+	[LIBSEAT_INFO] = "[INFO]",
+	[LIBSEAT_DEBUG] = "[DEBUG]",
+};
+
+static void timespec_sub(struct timespec *r, const struct timespec *a, const struct timespec *b) {
+	r->tv_sec = a->tv_sec - b->tv_sec;
+	r->tv_nsec = a->tv_nsec - b->tv_nsec;
+	if (r->tv_nsec < 0) {
+		r->tv_sec--;
+		r->tv_nsec += NSEC_PER_SEC;
+	}
+}
+
+void libseat_log_init(enum libseat_log_level level) {
+	if (start_time.tv_sec >= 0) {
+		return;
+	}
+	clock_gettime(CLOCK_MONOTONIC, &start_time);
+	current_log_level = level;
+	colored = isatty(STDERR_FILENO);
+}
+
+void _libseat_logf(enum libseat_log_level level, const char *fmt, ...) {
+	int stored_errno = errno;
+	va_list args;
+	if (level < current_log_level) {
+		return;
+	}
+
+	struct timespec ts = {0};
+	clock_gettime(CLOCK_MONOTONIC, &ts);
+	timespec_sub(&ts, &ts, &start_time);
+	unsigned c = (level < LIBSEAT_LOG_LEVEL_LAST) ? level : LIBSEAT_LOG_LEVEL_LAST - 1;
+
+	const char *prefix, *postfix;
+
+	if (colored) {
+		prefix = verbosity_colors[c];
+		postfix = "\x1B[0m\n";
+	} else {
+		prefix = verbosity_headers[c];
+		postfix = "\n";
+	}
+
+	fprintf(stderr, "%02d:%02d:%02d.%03ld %s ", (int)(ts.tv_sec / 60 / 60),
+		(int)(ts.tv_sec / 60 % 60), (int)(ts.tv_sec % 60), ts.tv_nsec / 1000000, prefix);
+
+	va_start(args, fmt);
+	vfprintf(stderr, fmt, args);
+	va_end(args);
+
+	fprintf(stderr, "%s", postfix);
+	errno = stored_errno;
+}

common/terminal.c

@@ -0,0 +1,202 @@
+#include "string.h"
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/kd.h>
+#include <linux/vt.h>
+#include <signal.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+
+#include "log.h"
+#include "terminal.h"
+
+#define TTYPATHLEN 64
+
+int terminal_current_vt(void) {
+	struct vt_stat st;
+	int fd = open("/dev/tty0", O_RDWR | O_NOCTTY);
+	if (fd == -1) {
+		log_errorf("could not open tty0: %s", strerror(errno));
+		return -1;
+	}
+	int res = ioctl(fd, VT_GETSTATE, &st);
+	close(fd);
+	if (res == -1) {
+		log_errorf("could not retrieve VT state: %s", strerror(errno));
+		return -1;
+	}
+	return st.v_active;
+}
+
+int terminal_setup(int vt) {
+	log_debugf("setting up vt %d", vt);
+	if (vt == -1) {
+		vt = 0;
+	}
+	char path[TTYPATHLEN];
+	if (snprintf(path, TTYPATHLEN, "/dev/tty%d", vt) == -1) {
+		log_errorf("could not generate tty path: %s", strerror(errno));
+		return -1;
+	}
+	int fd = open(path, O_RDWR | O_NOCTTY);
+	if (fd == -1) {
+		log_errorf("could not open target tty: %s", strerror(errno));
+		return -1;
+	}
+
+	static struct vt_mode mode = {
+		.mode = VT_PROCESS,
+		.waitv = 0,
+		.relsig = SIGUSR1,
+		.acqsig = SIGUSR2,
+		.frsig = 0,
+	};
+
+	int res = ioctl(fd, VT_SETMODE, &mode);
+	close(fd);
+	if (res == -1) {
+		log_errorf("could not set VT mode: %s", strerror(errno));
+	}
+
+	return res;
+}
+
+int terminal_teardown(int vt) {
+	log_debugf("tearing down vt %d", vt);
+	if (vt == -1) {
+		vt = 0;
+	}
+	char path[TTYPATHLEN];
+	if (snprintf(path, TTYPATHLEN, "/dev/tty%d", vt) == -1) {
+		log_errorf("could not generate tty path: %s", strerror(errno));
+		return -1;
+	}
+	int fd = open(path, O_RDWR | O_NOCTTY);
+	if (fd == -1) {
+		log_errorf("could not open target tty: %s", strerror(errno));
+		return -1;
+	}
+	if (ioctl(fd, KDSETMODE, KD_TEXT) == -1) {
+		log_errorf("could not set KD graphics mode: %s", strerror(errno));
+		close(fd);
+		return -1;
+	}
+	if (ioctl(fd, KDSKBMODE, K_UNICODE) == -1) {
+		log_errorf("could not set KD keyboard mode: %s", strerror(errno));
+		close(fd);
+		return -1;
+	}
+
+	static struct vt_mode mode = {
+		.mode = VT_PROCESS,
+		.waitv = 0,
+		.relsig = SIGUSR1,
+		.acqsig = SIGUSR2,
+		.frsig = 0,
+	};
+	if (ioctl(fd, VT_SETMODE, &mode) == -1) {
+		log_errorf("could not set VT mode: %s", strerror(errno));
+		close(fd);
+		return -1;
+	}
+
+	close(fd);
+	return 0;
+}
+
+int terminal_switch_vt(int vt) {
+	log_debugf("switching to vt %d", vt);
+	int fd = open("/dev/tty0", O_RDWR | O_NOCTTY);
+	if (fd == -1) {
+		log_errorf("could not open tty0: %s", strerror(errno));
+		return -1;
+	}
+
+	static struct vt_mode mode = {
+		.mode = VT_PROCESS,
+		.waitv = 0,
+		.relsig = SIGUSR1,
+		.acqsig = SIGUSR2,
+		.frsig = 0,
+	};
+
+	if (ioctl(fd, VT_SETMODE, &mode) == -1) {
+		log_errorf("could not set VT mode: %s", strerror(errno));
+		close(fd);
+		return -1;
+	}
+
+	if (ioctl(fd, VT_ACTIVATE, vt) == -1) {
+		log_errorf("could not activate VT: %s", strerror(errno));
+		close(fd);
+		return -1;
+	}
+
+	close(fd);
+	return 0;
+}
+
+int terminal_ack_switch(void) {
+	log_debug("acking vt switch");
+	int fd = open("/dev/tty0", O_RDWR | O_NOCTTY);
+	if (fd == -1) {
+		log_errorf("could not open tty0: %s", strerror(errno));
+		return -1;
+	}
+
+	int res = ioctl(fd, VT_RELDISP, VT_ACKACQ);
+	close(fd);
+	if (res == -1) {
+		log_errorf("could not ack VT switch: %s", strerror(errno));
+	}
+
+	return res;
+}
+
+int terminal_set_keyboard(int vt, bool enable) {
+	log_debugf("setting KD keyboard state to %d on vt %d", enable, vt);
+	if (vt == -1) {
+		vt = 0;
+	}
+	char path[TTYPATHLEN];
+	if (snprintf(path, TTYPATHLEN, "/dev/tty%d", vt) == -1) {
+		log_errorf("could not generate tty path: %s", strerror(errno));
+		return -1;
+	}
+	int fd = open(path, O_RDWR | O_NOCTTY);
+	if (fd == -1) {
+		log_errorf("could not generate tty path: %s", strerror(errno));
+		return -1;
+	}
+	int res = ioctl(fd, KDSKBMODE, enable ? K_UNICODE : K_OFF);
+	close(fd);
+	if (res == -1) {
+		log_errorf("could not set KD keyboard mode: %s", strerror(errno));
+	}
+	return res;
+}
+
+int terminal_set_graphics(int vt, bool enable) {
+	log_debugf("setting KD graphics state to %d on vt %d", enable, vt);
+	if (vt == -1) {
+		vt = 0;
+	}
+	char path[TTYPATHLEN];
+	if (snprintf(path, TTYPATHLEN, "/dev/tty%d", vt) == -1) {
+		log_errorf("could not generate tty path: %s", strerror(errno));
+		return -1;
+	}
+	int fd = open(path, O_RDWR | O_NOCTTY);
+	if (fd == -1) {
+		log_errorf("could not generate tty path: %s", strerror(errno));
+		return -1;
+	}
+	int res = ioctl(fd, KDSETMODE, enable ? KD_GRAPHICS : KD_TEXT);
+	close(fd);
+	if (res == -1) {
+		log_errorf("could not set KD graphics mode: %s", strerror(errno));
+	}
+	return res;
+}