1 /* SPDX-License-Identifier: LGPL-2.1+ */
3 This file is part of systemd.
5 Copyright 2013 David Herrmann
7 systemd is free software; you can redistribute it and/or modify it
8 under the terms of the GNU Lesser General Public License as published by
9 the Free Software Foundation; either version 2.1 of the License, or
10 (at your option) any later version.
12 systemd is distributed in the hope that it will be useful, but
13 WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 Lesser General Public License for more details.
17 You should have received a copy of the GNU Lesser General Public License
18 along with systemd; If not, see <http://www.gnu.org/licenses/>.
22 #include <linux/input.h>
24 #include <sys/ioctl.h>
25 #include <sys/types.h>
27 #if 0 /// elogind needs the systems udev header
33 #include "alloc-util.h"
36 #include "logind-session-device.h"
38 #include "parse-util.h"
39 #include "sd-daemon.h"
42 enum SessionDeviceNotifications {
43 SESSION_DEVICE_RESUME,
44 SESSION_DEVICE_TRY_PAUSE,
46 SESSION_DEVICE_RELEASE,
49 static int session_device_notify(SessionDevice *sd, enum SessionDeviceNotifications type) {
50 _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
51 _cleanup_free_ char *path = NULL;
53 uint32_t major, minor;
58 major = major(sd->dev);
59 minor = minor(sd->dev);
61 if (!sd->session->controller)
64 path = session_bus_path(sd->session);
68 r = sd_bus_message_new_signal(
69 sd->session->manager->bus,
71 "org.freedesktop.login1.Session",
72 (type == SESSION_DEVICE_RESUME) ? "ResumeDevice" : "PauseDevice");
76 r = sd_bus_message_set_destination(m, sd->session->controller);
82 case SESSION_DEVICE_RESUME:
83 r = sd_bus_message_append(m, "uuh", major, minor, sd->fd);
88 case SESSION_DEVICE_TRY_PAUSE:
92 case SESSION_DEVICE_PAUSE:
96 case SESSION_DEVICE_RELEASE:
105 r = sd_bus_message_append(m, "uus", major, minor, t);
110 return sd_bus_send(sd->session->manager->bus, m, NULL);
113 static int sd_eviocrevoke(int fd) {
114 static bool warned = false;
118 if (ioctl(fd, EVIOCREVOKE, NULL) < 0) {
120 if (errno == EINVAL && !warned) {
121 log_warning_errno(errno, "Kernel does not support evdev-revocation: %m");
129 static int sd_drmsetmaster(int fd) {
132 if (ioctl(fd, DRM_IOCTL_SET_MASTER, 0) < 0)
138 static int sd_drmdropmaster(int fd) {
141 if (ioctl(fd, DRM_IOCTL_DROP_MASTER, 0) < 0)
147 static int session_device_open(SessionDevice *sd, bool active) {
151 assert(sd->type != DEVICE_TYPE_UNKNOWN);
154 /* open device and try to get an udev_device from it */
155 fd = open(sd->node, O_RDWR|O_CLOEXEC|O_NOCTTY|O_NONBLOCK);
161 case DEVICE_TYPE_DRM:
163 /* Weird legacy DRM semantics might return an error even though we're master. No way to detect
164 * that so fail at all times and let caller retry in inactive state. */
165 r = sd_drmsetmaster(fd);
171 /* DRM-Master is granted to the first user who opens a device automatically (ughh,
172 * racy!). Hence, we just drop DRM-Master in case we were the first. */
173 sd_drmdropmaster(fd);
176 case DEVICE_TYPE_EVDEV:
181 case DEVICE_TYPE_UNKNOWN:
183 /* fallback for devices wihout synchronizations */
190 static int session_device_start(SessionDevice *sd) {
194 assert(session_is_active(sd->session));
201 case DEVICE_TYPE_DRM:
202 /* Device is kept open. Simply call drmSetMaster() and hope there is no-one else. In case it fails, we
203 * keep the device paused. Maybe at some point we have a drmStealMaster(). */
204 r = sd_drmsetmaster(sd->fd);
209 case DEVICE_TYPE_EVDEV:
210 /* Evdev devices are revoked while inactive. Reopen it and we are fine. */
211 r = session_device_open(sd, true);
215 /* For evdev devices, the file descriptor might be left uninitialized. This might happen while resuming
216 * into a session and logind has been restarted right before. */
221 case DEVICE_TYPE_UNKNOWN:
223 /* fallback for devices wihout synchronizations */
231 static void session_device_stop(SessionDevice *sd) {
238 case DEVICE_TYPE_DRM:
239 /* On DRM devices we simply drop DRM-Master but keep it open.
240 * This allows the user to keep resources allocated. The
241 * CAP_SYS_ADMIN restriction to DRM-Master prevents users from
242 * circumventing this. */
243 sd_drmdropmaster(sd->fd);
245 case DEVICE_TYPE_EVDEV:
246 /* Revoke access on evdev file-descriptors during deactivation.
247 * This will basically prevent any operations on the fd and
248 * cannot be undone. Good side is: it needs no CAP_SYS_ADMIN
249 * protection this way. */
250 sd_eviocrevoke(sd->fd);
252 case DEVICE_TYPE_UNKNOWN:
254 /* fallback for devices without synchronization */
261 static DeviceType detect_device_type(struct udev_device *dev) {
262 const char *sysname, *subsystem;
265 sysname = udev_device_get_sysname(dev);
266 subsystem = udev_device_get_subsystem(dev);
267 type = DEVICE_TYPE_UNKNOWN;
269 if (streq_ptr(subsystem, "drm")) {
270 if (startswith(sysname, "card"))
271 type = DEVICE_TYPE_DRM;
272 } else if (streq_ptr(subsystem, "input")) {
273 if (startswith(sysname, "event"))
274 type = DEVICE_TYPE_EVDEV;
280 static int session_device_verify(SessionDevice *sd) {
281 struct udev_device *dev, *p = NULL;
282 const char *sp, *node;
285 dev = udev_device_new_from_devnum(sd->session->manager->udev, 'c', sd->dev);
289 sp = udev_device_get_syspath(dev);
290 node = udev_device_get_devnode(dev);
296 /* detect device type so we can find the correct sysfs parent */
297 sd->type = detect_device_type(dev);
298 if (sd->type == DEVICE_TYPE_UNKNOWN) {
301 } else if (sd->type == DEVICE_TYPE_EVDEV) {
302 /* for evdev devices we need the parent node as device */
304 dev = udev_device_get_parent_with_subsystem_devtype(p, "input", NULL);
309 sp = udev_device_get_syspath(dev);
310 } else if (sd->type != DEVICE_TYPE_DRM) {
311 /* Prevent opening unsupported devices. Especially devices of
312 * subsystem "input" must be opened via the evdev node as
313 * we require EVIOCREVOKE. */
318 /* search for an existing seat device and return it if available */
319 sd->device = hashmap_get(sd->session->manager->devices, sp);
321 /* The caller might have gotten the udev event before we were
322 * able to process it. Hence, fake the "add" event and let the
323 * logind-manager handle the new device. */
324 r = manager_process_seat_device(sd->session->manager, dev);
328 /* if it's still not available, then the device is invalid */
329 sd->device = hashmap_get(sd->session->manager->devices, sp);
336 if (sd->device->seat != sd->session->seat) {
341 sd->node = strdup(node);
349 udev_device_unref(p ? : dev);
353 int session_device_new(Session *s, dev_t dev, bool open_device, SessionDevice **out) {
363 sd = new0(SessionDevice, 1);
370 sd->type = DEVICE_TYPE_UNKNOWN;
372 r = session_device_verify(sd);
376 r = hashmap_put(s->devices, &sd->dev, sd);
383 /* Open the device for the first time. We need a valid fd to pass back
384 * to the caller. If the session is not active, this _might_ immediately
385 * revoke access and thus invalidate the fd. But this is still needed
386 * to pass a valid fd back. */
387 sd->active = session_is_active(s);
388 r = session_device_open(sd, sd->active);
390 /* EINVAL _may_ mean a master is active; retry inactive */
391 if (sd->active && r == -EINVAL) {
393 r = session_device_open(sd, false);
401 LIST_PREPEND(sd_by_device, sd->device->session_devices, sd);
407 hashmap_remove(s->devices, &sd->dev);
413 void session_device_free(SessionDevice *sd) {
419 /* Remove the pushed fd again, just in case. */
421 m = strjoina("FDSTOREREMOVE=1\n"
422 "FDNAME=session-", sd->session->id);
424 (void) sd_notify(false, m);
427 session_device_stop(sd);
428 session_device_notify(sd, SESSION_DEVICE_RELEASE);
429 close_nointr(sd->fd);
431 LIST_REMOVE(sd_by_device, sd->device->session_devices, sd);
433 hashmap_remove(sd->session->devices, &sd->dev);
439 void session_device_complete_pause(SessionDevice *sd) {
446 session_device_stop(sd);
448 /* if not all devices are paused, wait for further completion events */
449 HASHMAP_FOREACH(iter, sd->session->devices, i)
453 /* complete any pending session switch */
454 seat_complete_switch(sd->session->seat);
457 void session_device_resume_all(Session *s) {
463 HASHMAP_FOREACH(sd, s->devices, i) {
465 if (session_device_start(sd) < 0)
467 if (session_device_save(sd) < 0)
469 session_device_notify(sd, SESSION_DEVICE_RESUME);
474 void session_device_pause_all(Session *s) {
480 HASHMAP_FOREACH(sd, s->devices, i) {
482 session_device_stop(sd);
483 session_device_notify(sd, SESSION_DEVICE_PAUSE);
488 unsigned int session_device_try_pause_all(Session *s) {
491 unsigned int num_pending = 0;
495 HASHMAP_FOREACH(sd, s->devices, i) {
497 session_device_notify(sd, SESSION_DEVICE_TRY_PAUSE);
505 int session_device_save(SessionDevice *sd) {
511 /* Store device fd in PID1. It will send it back to us on restart so revocation will continue to work. To make
512 * things simple, send fds for all type of devices even if they don't support the revocation mechanism so we
513 * don't have to handle them differently later.
515 * Note: for device supporting revocation, PID1 will drop a stored fd automatically if the corresponding device
521 m = strjoina("FDSTORE=1\n"
522 "FDNAME=session", sd->session->id);
524 r = sd_pid_notify_with_fds(0, false, m, &sd->fd, 1);
528 sd->pushed_fd = true;
532 void session_device_attach_fd(SessionDevice *sd, int fd, bool active) {