1 /* SPDX-License-Identifier: LGPL-2.1+ */
3 This file is part of systemd.
5 Copyright 2013 David Herrmann
9 #include <linux/input.h>
11 #include <sys/ioctl.h>
12 #include <sys/types.h>
14 #if 0 /// elogind needs the systems udev header
20 #include "alloc-util.h"
23 #include "logind-session-device.h"
25 #include "parse-util.h"
26 #include "sd-daemon.h"
29 enum SessionDeviceNotifications {
30 SESSION_DEVICE_RESUME,
31 SESSION_DEVICE_TRY_PAUSE,
33 SESSION_DEVICE_RELEASE,
36 static int session_device_notify(SessionDevice *sd, enum SessionDeviceNotifications type) {
37 _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
38 _cleanup_free_ char *path = NULL;
40 uint32_t major, minor;
45 major = major(sd->dev);
46 minor = minor(sd->dev);
48 if (!sd->session->controller)
51 path = session_bus_path(sd->session);
55 r = sd_bus_message_new_signal(
56 sd->session->manager->bus,
58 "org.freedesktop.login1.Session",
59 (type == SESSION_DEVICE_RESUME) ? "ResumeDevice" : "PauseDevice");
63 r = sd_bus_message_set_destination(m, sd->session->controller);
69 case SESSION_DEVICE_RESUME:
70 r = sd_bus_message_append(m, "uuh", major, minor, sd->fd);
75 case SESSION_DEVICE_TRY_PAUSE:
79 case SESSION_DEVICE_PAUSE:
83 case SESSION_DEVICE_RELEASE:
92 r = sd_bus_message_append(m, "uus", major, minor, t);
97 return sd_bus_send(sd->session->manager->bus, m, NULL);
100 static void sd_eviocrevoke(int fd) {
101 static bool warned = false;
105 if (ioctl(fd, EVIOCREVOKE, NULL) < 0) {
107 if (errno == EINVAL && !warned) {
108 log_warning_errno(errno, "Kernel does not support evdev-revocation: %m");
114 static int sd_drmsetmaster(int fd) {
117 if (ioctl(fd, DRM_IOCTL_SET_MASTER, 0) < 0)
123 static int sd_drmdropmaster(int fd) {
126 if (ioctl(fd, DRM_IOCTL_DROP_MASTER, 0) < 0)
132 static int session_device_open(SessionDevice *sd, bool active) {
136 assert(sd->type != DEVICE_TYPE_UNKNOWN);
139 /* open device and try to get an udev_device from it */
140 fd = open(sd->node, O_RDWR|O_CLOEXEC|O_NOCTTY|O_NONBLOCK);
146 case DEVICE_TYPE_DRM:
148 /* Weird legacy DRM semantics might return an error even though we're master. No way to detect
149 * that so fail at all times and let caller retry in inactive state. */
150 r = sd_drmsetmaster(fd);
156 /* DRM-Master is granted to the first user who opens a device automatically (ughh,
157 * racy!). Hence, we just drop DRM-Master in case we were the first. */
158 (void) sd_drmdropmaster(fd);
161 case DEVICE_TYPE_EVDEV:
166 case DEVICE_TYPE_UNKNOWN:
168 /* fallback for devices wihout synchronizations */
175 static int session_device_start(SessionDevice *sd) {
179 assert(session_is_active(sd->session));
186 case DEVICE_TYPE_DRM:
188 log_error("Failed to re-activate DRM fd, as the fd was lost (maybe logind restart went wrong?)");
192 /* Device is kept open. Simply call drmSetMaster() and hope there is no-one else. In case it fails, we
193 * keep the device paused. Maybe at some point we have a drmStealMaster(). */
194 r = sd_drmsetmaster(sd->fd);
199 case DEVICE_TYPE_EVDEV:
200 /* Evdev devices are revoked while inactive. Reopen it and we are fine. */
201 r = session_device_open(sd, true);
205 /* For evdev devices, the file descriptor might be left uninitialized. This might happen while resuming
206 * into a session and logind has been restarted right before. */
211 case DEVICE_TYPE_UNKNOWN:
213 /* fallback for devices without synchronizations */
221 static void session_device_stop(SessionDevice *sd) {
229 case DEVICE_TYPE_DRM:
231 log_error("Failed to de-activate DRM fd, as the fd was lost (maybe logind restart went wrong?)");
235 /* On DRM devices we simply drop DRM-Master but keep it open.
236 * This allows the user to keep resources allocated. The
237 * CAP_SYS_ADMIN restriction to DRM-Master prevents users from
238 * circumventing this. */
239 sd_drmdropmaster(sd->fd);
242 case DEVICE_TYPE_EVDEV:
243 /* Revoke access on evdev file-descriptors during deactivation.
244 * This will basically prevent any operations on the fd and
245 * cannot be undone. Good side is: it needs no CAP_SYS_ADMIN
246 * protection this way. */
247 sd_eviocrevoke(sd->fd);
250 case DEVICE_TYPE_UNKNOWN:
252 /* fallback for devices without synchronization */
259 static DeviceType detect_device_type(struct udev_device *dev) {
260 const char *sysname, *subsystem;
263 sysname = udev_device_get_sysname(dev);
264 subsystem = udev_device_get_subsystem(dev);
265 type = DEVICE_TYPE_UNKNOWN;
267 if (streq_ptr(subsystem, "drm")) {
268 if (startswith(sysname, "card"))
269 type = DEVICE_TYPE_DRM;
270 } else if (streq_ptr(subsystem, "input")) {
271 if (startswith(sysname, "event"))
272 type = DEVICE_TYPE_EVDEV;
278 static int session_device_verify(SessionDevice *sd) {
279 struct udev_device *dev, *p = NULL;
280 const char *sp, *node;
283 dev = udev_device_new_from_devnum(sd->session->manager->udev, 'c', sd->dev);
287 sp = udev_device_get_syspath(dev);
288 node = udev_device_get_devnode(dev);
294 /* detect device type so we can find the correct sysfs parent */
295 sd->type = detect_device_type(dev);
296 if (sd->type == DEVICE_TYPE_UNKNOWN) {
299 } else if (sd->type == DEVICE_TYPE_EVDEV) {
300 /* for evdev devices we need the parent node as device */
302 dev = udev_device_get_parent_with_subsystem_devtype(p, "input", NULL);
307 sp = udev_device_get_syspath(dev);
308 } else if (sd->type != DEVICE_TYPE_DRM) {
309 /* Prevent opening unsupported devices. Especially devices of
310 * subsystem "input" must be opened via the evdev node as
311 * we require EVIOCREVOKE. */
316 /* search for an existing seat device and return it if available */
317 sd->device = hashmap_get(sd->session->manager->devices, sp);
319 /* The caller might have gotten the udev event before we were
320 * able to process it. Hence, fake the "add" event and let the
321 * logind-manager handle the new device. */
322 r = manager_process_seat_device(sd->session->manager, dev);
326 /* if it's still not available, then the device is invalid */
327 sd->device = hashmap_get(sd->session->manager->devices, sp);
334 if (sd->device->seat != sd->session->seat) {
339 sd->node = strdup(node);
347 udev_device_unref(p ? : dev);
351 int session_device_new(Session *s, dev_t dev, bool open_device, SessionDevice **out) {
361 sd = new0(SessionDevice, 1);
368 sd->type = DEVICE_TYPE_UNKNOWN;
370 r = session_device_verify(sd);
374 r = hashmap_put(s->devices, &sd->dev, sd);
379 /* Open the device for the first time. We need a valid fd to pass back
380 * to the caller. If the session is not active, this _might_ immediately
381 * revoke access and thus invalidate the fd. But this is still needed
382 * to pass a valid fd back. */
383 sd->active = session_is_active(s);
384 r = session_device_open(sd, sd->active);
386 /* EINVAL _may_ mean a master is active; retry inactive */
387 if (sd->active && r == -EINVAL) {
389 r = session_device_open(sd, false);
397 LIST_PREPEND(sd_by_device, sd->device->session_devices, sd);
403 hashmap_remove(s->devices, &sd->dev);
409 void session_device_free(SessionDevice *sd) {
412 /* Make sure to remove the pushed fd. */
414 _cleanup_free_ char *m = NULL;
418 /* Session ID does not contain separators. */
419 id = sd->session->id;
420 assert(*(id + strcspn(id, "-\n")) == '\0');
422 r = asprintf(&m, "FDSTOREREMOVE=1\n"
423 "FDNAME=session-%s-device-%u-%u\n",
424 id, major(sd->dev), minor(sd->dev));
426 (void) sd_notify(false, m);
429 session_device_stop(sd);
430 session_device_notify(sd, SESSION_DEVICE_RELEASE);
433 LIST_REMOVE(sd_by_device, sd->device->session_devices, sd);
435 hashmap_remove(sd->session->devices, &sd->dev);
441 void session_device_complete_pause(SessionDevice *sd) {
448 session_device_stop(sd);
450 /* if not all devices are paused, wait for further completion events */
451 HASHMAP_FOREACH(iter, sd->session->devices, i)
455 /* complete any pending session switch */
456 seat_complete_switch(sd->session->seat);
459 void session_device_resume_all(Session *s) {
465 HASHMAP_FOREACH(sd, s->devices, i) {
469 if (session_device_start(sd) < 0)
471 if (session_device_save(sd) < 0)
474 session_device_notify(sd, SESSION_DEVICE_RESUME);
478 void session_device_pause_all(Session *s) {
484 HASHMAP_FOREACH(sd, s->devices, i) {
488 session_device_stop(sd);
489 session_device_notify(sd, SESSION_DEVICE_PAUSE);
493 unsigned int session_device_try_pause_all(Session *s) {
494 unsigned num_pending = 0;
500 HASHMAP_FOREACH(sd, s->devices, i) {
504 session_device_notify(sd, SESSION_DEVICE_TRY_PAUSE);
511 int session_device_save(SessionDevice *sd) {
512 _cleanup_free_ char *m = NULL;
518 /* Store device fd in PID1. It will send it back to us on restart so revocation will continue to work. To make
519 * things simple, send fds for all type of devices even if they don't support the revocation mechanism so we
520 * don't have to handle them differently later.
522 * Note: for device supporting revocation, PID1 will drop a stored fd automatically if the corresponding device
528 /* Session ID does not contain separators. */
529 id = sd->session->id;
530 assert(*(id + strcspn(id, "-\n")) == '\0');
532 r = asprintf(&m, "FDSTORE=1\n"
533 "FDNAME=session-%s-device-%u-%u\n",
534 id, major(sd->dev), minor(sd->dev));
538 r = sd_pid_notify_with_fds(0, false, m, &sd->fd, 1);
542 sd->pushed_fd = true;
546 void session_device_attach_fd(SessionDevice *sd, int fd, bool active) {
553 sd->pushed_fd = true;