483 lines
14 KiB
C
483 lines
14 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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/***
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This file is part of systemd.
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Copyright 2013 David Herrmann
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <fcntl.h>
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#include <linux/input.h>
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#include <string.h>
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#include <sys/ioctl.h>
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#include <sys/types.h>
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#include "libudev.h"
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#include "alloc-util.h"
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#include "bus-util.h"
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#include "fd-util.h"
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#include "logind-session-device.h"
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#include "missing.h"
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#include "util.h"
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enum SessionDeviceNotifications {
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SESSION_DEVICE_RESUME,
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SESSION_DEVICE_TRY_PAUSE,
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SESSION_DEVICE_PAUSE,
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SESSION_DEVICE_RELEASE,
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};
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static int session_device_notify(SessionDevice *sd, enum SessionDeviceNotifications type) {
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_cleanup_bus_message_unref_ sd_bus_message *m = NULL;
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_cleanup_free_ char *path = NULL;
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const char *t = NULL;
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uint32_t major, minor;
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int r;
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assert(sd);
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major = major(sd->dev);
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minor = minor(sd->dev);
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if (!sd->session->controller)
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return 0;
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path = session_bus_path(sd->session);
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if (!path)
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return -ENOMEM;
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r = sd_bus_message_new_signal(
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sd->session->manager->bus,
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&m, path,
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"org.freedesktop.login1.Session",
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(type == SESSION_DEVICE_RESUME) ? "ResumeDevice" : "PauseDevice");
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if (!m)
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return r;
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r = sd_bus_message_set_destination(m, sd->session->controller);
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if (r < 0)
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return r;
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switch (type) {
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case SESSION_DEVICE_RESUME:
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r = sd_bus_message_append(m, "uuh", major, minor, sd->fd);
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if (r < 0)
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return r;
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break;
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case SESSION_DEVICE_TRY_PAUSE:
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t = "pause";
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break;
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case SESSION_DEVICE_PAUSE:
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t = "force";
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break;
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case SESSION_DEVICE_RELEASE:
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t = "gone";
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break;
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default:
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return -EINVAL;
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}
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if (t) {
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r = sd_bus_message_append(m, "uus", major, minor, t);
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if (r < 0)
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return r;
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}
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return sd_bus_send(sd->session->manager->bus, m, NULL);
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}
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static int sd_eviocrevoke(int fd) {
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static bool warned;
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int r;
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assert(fd >= 0);
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r = ioctl(fd, EVIOCREVOKE, NULL);
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if (r < 0) {
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r = -errno;
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if (r == -EINVAL && !warned) {
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warned = true;
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log_warning("kernel does not support evdev-revocation");
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}
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}
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return 0;
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}
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static int sd_drmsetmaster(int fd) {
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int r;
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assert(fd >= 0);
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r = ioctl(fd, DRM_IOCTL_SET_MASTER, 0);
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if (r < 0)
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return -errno;
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return 0;
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}
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static int sd_drmdropmaster(int fd) {
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int r;
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assert(fd >= 0);
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r = ioctl(fd, DRM_IOCTL_DROP_MASTER, 0);
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if (r < 0)
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return -errno;
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return 0;
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}
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static int session_device_open(SessionDevice *sd, bool active) {
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int fd, r;
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assert(sd->type != DEVICE_TYPE_UNKNOWN);
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/* open device and try to get an udev_device from it */
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fd = open(sd->node, O_RDWR|O_CLOEXEC|O_NOCTTY|O_NONBLOCK);
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if (fd < 0)
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return -errno;
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switch (sd->type) {
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case DEVICE_TYPE_DRM:
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if (active) {
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/* Weird legacy DRM semantics might return an error
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* even though we're master. No way to detect that so
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* fail at all times and let caller retry in inactive
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* state. */
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r = sd_drmsetmaster(fd);
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if (r < 0) {
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close_nointr(fd);
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return r;
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}
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} else {
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/* DRM-Master is granted to the first user who opens a
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* device automatically (ughh, racy!). Hence, we just
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* drop DRM-Master in case we were the first. */
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sd_drmdropmaster(fd);
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}
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break;
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case DEVICE_TYPE_EVDEV:
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if (!active)
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sd_eviocrevoke(fd);
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break;
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case DEVICE_TYPE_UNKNOWN:
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default:
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/* fallback for devices wihout synchronizations */
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break;
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}
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return fd;
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}
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static int session_device_start(SessionDevice *sd) {
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int r;
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assert(sd);
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assert(session_is_active(sd->session));
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if (sd->active)
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return 0;
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switch (sd->type) {
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case DEVICE_TYPE_DRM:
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/* Device is kept open. Simply call drmSetMaster() and hope
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* there is no-one else. In case it fails, we keep the device
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* paused. Maybe at some point we have a drmStealMaster(). */
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r = sd_drmsetmaster(sd->fd);
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if (r < 0)
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return r;
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break;
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case DEVICE_TYPE_EVDEV:
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/* Evdev devices are revoked while inactive. Reopen it and we
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* are fine. */
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r = session_device_open(sd, true);
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if (r < 0)
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return r;
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close_nointr(sd->fd);
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sd->fd = r;
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break;
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case DEVICE_TYPE_UNKNOWN:
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default:
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/* fallback for devices wihout synchronizations */
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break;
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}
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sd->active = true;
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return 0;
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}
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static void session_device_stop(SessionDevice *sd) {
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assert(sd);
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if (!sd->active)
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return;
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switch (sd->type) {
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case DEVICE_TYPE_DRM:
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/* On DRM devices we simply drop DRM-Master but keep it open.
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* This allows the user to keep resources allocated. The
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* CAP_SYS_ADMIN restriction to DRM-Master prevents users from
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* circumventing this. */
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sd_drmdropmaster(sd->fd);
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break;
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case DEVICE_TYPE_EVDEV:
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/* Revoke access on evdev file-descriptors during deactivation.
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* This will basically prevent any operations on the fd and
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* cannot be undone. Good side is: it needs no CAP_SYS_ADMIN
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* protection this way. */
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sd_eviocrevoke(sd->fd);
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break;
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case DEVICE_TYPE_UNKNOWN:
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default:
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/* fallback for devices without synchronization */
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break;
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}
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sd->active = false;
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}
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static DeviceType detect_device_type(struct udev_device *dev) {
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const char *sysname, *subsystem;
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DeviceType type;
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sysname = udev_device_get_sysname(dev);
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subsystem = udev_device_get_subsystem(dev);
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type = DEVICE_TYPE_UNKNOWN;
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if (streq_ptr(subsystem, "drm")) {
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if (startswith(sysname, "card"))
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type = DEVICE_TYPE_DRM;
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} else if (streq_ptr(subsystem, "input")) {
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if (startswith(sysname, "event"))
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type = DEVICE_TYPE_EVDEV;
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}
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return type;
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}
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static int session_device_verify(SessionDevice *sd) {
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struct udev_device *dev, *p = NULL;
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const char *sp, *node;
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int r;
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dev = udev_device_new_from_devnum(sd->session->manager->udev, 'c', sd->dev);
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if (!dev)
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return -ENODEV;
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sp = udev_device_get_syspath(dev);
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node = udev_device_get_devnode(dev);
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if (!node) {
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r = -EINVAL;
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goto err_dev;
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}
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/* detect device type so we can find the correct sysfs parent */
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sd->type = detect_device_type(dev);
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if (sd->type == DEVICE_TYPE_UNKNOWN) {
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r = -ENODEV;
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goto err_dev;
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} else if (sd->type == DEVICE_TYPE_EVDEV) {
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/* for evdev devices we need the parent node as device */
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p = dev;
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dev = udev_device_get_parent_with_subsystem_devtype(p, "input", NULL);
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if (!dev) {
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r = -ENODEV;
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goto err_dev;
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}
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sp = udev_device_get_syspath(dev);
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} else if (sd->type != DEVICE_TYPE_DRM) {
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/* Prevent opening unsupported devices. Especially devices of
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* subsystem "input" must be opened via the evdev node as
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* we require EVIOCREVOKE. */
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r = -ENODEV;
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goto err_dev;
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}
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/* search for an existing seat device and return it if available */
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sd->device = hashmap_get(sd->session->manager->devices, sp);
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if (!sd->device) {
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/* The caller might have gotten the udev event before we were
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* able to process it. Hence, fake the "add" event and let the
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* logind-manager handle the new device. */
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r = manager_process_seat_device(sd->session->manager, dev);
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if (r < 0)
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goto err_dev;
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/* if it's still not available, then the device is invalid */
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sd->device = hashmap_get(sd->session->manager->devices, sp);
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if (!sd->device) {
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r = -ENODEV;
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goto err_dev;
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}
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}
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if (sd->device->seat != sd->session->seat) {
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r = -EPERM;
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goto err_dev;
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}
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sd->node = strdup(node);
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if (!sd->node) {
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r = -ENOMEM;
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goto err_dev;
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}
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r = 0;
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err_dev:
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udev_device_unref(p ? : dev);
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return r;
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}
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int session_device_new(Session *s, dev_t dev, SessionDevice **out) {
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SessionDevice *sd;
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int r;
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assert(s);
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assert(out);
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if (!s->seat)
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return -EPERM;
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sd = new0(SessionDevice, 1);
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if (!sd)
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return -ENOMEM;
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sd->session = s;
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sd->dev = dev;
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sd->fd = -1;
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sd->type = DEVICE_TYPE_UNKNOWN;
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r = session_device_verify(sd);
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if (r < 0)
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goto error;
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r = hashmap_put(s->devices, &sd->dev, sd);
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if (r < 0) {
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r = -ENOMEM;
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goto error;
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}
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/* Open the device for the first time. We need a valid fd to pass back
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* to the caller. If the session is not active, this _might_ immediately
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* revoke access and thus invalidate the fd. But this is still needed
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* to pass a valid fd back. */
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sd->active = session_is_active(s);
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r = session_device_open(sd, sd->active);
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if (r < 0) {
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/* EINVAL _may_ mean a master is active; retry inactive */
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if (sd->active && r == -EINVAL) {
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sd->active = false;
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r = session_device_open(sd, false);
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}
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if (r < 0)
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goto error;
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}
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sd->fd = r;
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LIST_PREPEND(sd_by_device, sd->device->session_devices, sd);
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*out = sd;
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return 0;
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error:
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hashmap_remove(s->devices, &sd->dev);
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free(sd->node);
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free(sd);
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return r;
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}
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void session_device_free(SessionDevice *sd) {
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assert(sd);
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session_device_stop(sd);
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session_device_notify(sd, SESSION_DEVICE_RELEASE);
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close_nointr(sd->fd);
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LIST_REMOVE(sd_by_device, sd->device->session_devices, sd);
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hashmap_remove(sd->session->devices, &sd->dev);
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free(sd->node);
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free(sd);
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}
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void session_device_complete_pause(SessionDevice *sd) {
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SessionDevice *iter;
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Iterator i;
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if (!sd->active)
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return;
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session_device_stop(sd);
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/* if not all devices are paused, wait for further completion events */
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HASHMAP_FOREACH(iter, sd->session->devices, i)
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if (iter->active)
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return;
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/* complete any pending session switch */
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seat_complete_switch(sd->session->seat);
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}
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void session_device_resume_all(Session *s) {
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SessionDevice *sd;
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Iterator i;
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int r;
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assert(s);
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HASHMAP_FOREACH(sd, s->devices, i) {
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if (!sd->active) {
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r = session_device_start(sd);
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if (!r)
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session_device_notify(sd, SESSION_DEVICE_RESUME);
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}
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}
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}
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void session_device_pause_all(Session *s) {
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SessionDevice *sd;
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Iterator i;
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assert(s);
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HASHMAP_FOREACH(sd, s->devices, i) {
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if (sd->active) {
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session_device_stop(sd);
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session_device_notify(sd, SESSION_DEVICE_PAUSE);
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}
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}
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}
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unsigned int session_device_try_pause_all(Session *s) {
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SessionDevice *sd;
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Iterator i;
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unsigned int num_pending = 0;
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assert(s);
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HASHMAP_FOREACH(sd, s->devices, i) {
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if (sd->active) {
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session_device_notify(sd, SESSION_DEVICE_TRY_PAUSE);
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++num_pending;
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}
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}
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return num_pending;
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}
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