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 void 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");
127 static int sd_drmsetmaster(int fd) {
130 if (ioctl(fd, DRM_IOCTL_SET_MASTER, 0) < 0)
136 static int sd_drmdropmaster(int fd) {
139 if (ioctl(fd, DRM_IOCTL_DROP_MASTER, 0) < 0)
145 static int session_device_open(SessionDevice *sd, bool active) {
149 assert(sd->type != DEVICE_TYPE_UNKNOWN);
152 /* open device and try to get an udev_device from it */
153 fd = open(sd->node, O_RDWR|O_CLOEXEC|O_NOCTTY|O_NONBLOCK);
159 case DEVICE_TYPE_DRM:
161 /* Weird legacy DRM semantics might return an error even though we're master. No way to detect
162 * that so fail at all times and let caller retry in inactive state. */
163 r = sd_drmsetmaster(fd);
169 /* DRM-Master is granted to the first user who opens a device automatically (ughh,
170 * racy!). Hence, we just drop DRM-Master in case we were the first. */
171 (void) sd_drmdropmaster(fd);
174 case DEVICE_TYPE_EVDEV:
179 case DEVICE_TYPE_UNKNOWN:
181 /* fallback for devices wihout synchronizations */
188 static int session_device_start(SessionDevice *sd) {
192 assert(session_is_active(sd->session));
199 case DEVICE_TYPE_DRM:
200 /* Device is kept open. Simply call drmSetMaster() and hope there is no-one else. In case it fails, we
201 * keep the device paused. Maybe at some point we have a drmStealMaster(). */
202 r = sd_drmsetmaster(sd->fd);
207 case DEVICE_TYPE_EVDEV:
208 /* Evdev devices are revoked while inactive. Reopen it and we are fine. */
209 r = session_device_open(sd, true);
213 /* For evdev devices, the file descriptor might be left uninitialized. This might happen while resuming
214 * into a session and logind has been restarted right before. */
219 case DEVICE_TYPE_UNKNOWN:
221 /* fallback for devices wihout synchronizations */
229 static void session_device_stop(SessionDevice *sd) {
236 case DEVICE_TYPE_DRM:
237 /* On DRM devices we simply drop DRM-Master but keep it open.
238 * This allows the user to keep resources allocated. The
239 * CAP_SYS_ADMIN restriction to DRM-Master prevents users from
240 * circumventing this. */
241 sd_drmdropmaster(sd->fd);
243 case DEVICE_TYPE_EVDEV:
244 /* Revoke access on evdev file-descriptors during deactivation.
245 * This will basically prevent any operations on the fd and
246 * cannot be undone. Good side is: it needs no CAP_SYS_ADMIN
247 * protection this way. */
248 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) {
415 /* Remove the pushed fd again, just in case. */
417 m = strjoina("FDSTOREREMOVE=1\n"
418 "FDNAME=session-", sd->session->id);
420 (void) sd_notify(false, m);
423 session_device_stop(sd);
424 session_device_notify(sd, SESSION_DEVICE_RELEASE);
427 LIST_REMOVE(sd_by_device, sd->device->session_devices, sd);
429 hashmap_remove(sd->session->devices, &sd->dev);
435 void session_device_complete_pause(SessionDevice *sd) {
442 session_device_stop(sd);
444 /* if not all devices are paused, wait for further completion events */
445 HASHMAP_FOREACH(iter, sd->session->devices, i)
449 /* complete any pending session switch */
450 seat_complete_switch(sd->session->seat);
453 void session_device_resume_all(Session *s) {
459 HASHMAP_FOREACH(sd, s->devices, i) {
463 if (session_device_start(sd) < 0)
465 if (session_device_save(sd) < 0)
467 session_device_notify(sd, SESSION_DEVICE_RESUME);
471 void session_device_pause_all(Session *s) {
477 HASHMAP_FOREACH(sd, s->devices, i) {
481 session_device_stop(sd);
482 session_device_notify(sd, SESSION_DEVICE_PAUSE);
486 unsigned int session_device_try_pause_all(Session *s) {
487 unsigned num_pending = 0;
493 HASHMAP_FOREACH(sd, s->devices, i) {
497 session_device_notify(sd, SESSION_DEVICE_TRY_PAUSE);
504 int session_device_save(SessionDevice *sd) {
510 /* Store device fd in PID1. It will send it back to us on restart so revocation will continue to work. To make
511 * things simple, send fds for all type of devices even if they don't support the revocation mechanism so we
512 * don't have to handle them differently later.
514 * Note: for device supporting revocation, PID1 will drop a stored fd automatically if the corresponding device
520 m = strjoina("FDSTORE=1\n"
521 "FDNAME=session", sd->session->id);
523 r = sd_pid_notify_with_fds(0, false, m, &sd->fd, 1);
527 sd->pushed_fd = true;
531 void session_device_attach_fd(SessionDevice *sd, int fd, bool active) {