--- /dev/null
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+ This file is part of systemd.
+
+ Copyright 2013 David Herrmann
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <assert.h>
+#include <fcntl.h>
+#include <libudev.h>
+#include <linux/input.h>
+#include <linux/ioctl.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "dbus-common.h"
+#include "logind-session-device.h"
+#include "util.h"
+#include "missing.h"
+
+enum SessionDeviceNotifications {
+ SESSION_DEVICE_RESUME,
+ SESSION_DEVICE_TRY_PAUSE,
+ SESSION_DEVICE_PAUSE,
+ SESSION_DEVICE_RELEASE,
+};
+
+static void session_device_notify(SessionDevice *sd, enum SessionDeviceNotifications type) {
+ _cleanup_dbus_message_unref_ DBusMessage *m = NULL;
+ _cleanup_free_ char *path = NULL;
+ const char *t = NULL;
+
+ assert(sd);
+
+ if (!sd->session->controller)
+ return;
+
+ path = session_bus_path(sd->session);
+ if (!path)
+ return;
+
+ m = dbus_message_new_signal(path,
+ "org.freedesktop.login1.Session",
+ (type == SESSION_DEVICE_RESUME) ? "ResumeDevice" : "PauseDevice");
+ if (!m)
+ return;
+
+ if (!dbus_message_set_destination(m, sd->session->controller))
+ return;
+
+ switch (type) {
+ case SESSION_DEVICE_RESUME:
+ if (!dbus_message_append_args(m,
+ DBUS_TYPE_UINT32, major(sd->dev),
+ DBUS_TYPE_UINT32, minor(sd->dev),
+ DBUS_TYPE_UNIX_FD, &sd->fd,
+ DBUS_TYPE_INVALID))
+ return;
+ break;
+ case SESSION_DEVICE_TRY_PAUSE:
+ t = "pause";
+ break;
+ case SESSION_DEVICE_PAUSE:
+ t = "force";
+ break;
+ case SESSION_DEVICE_RELEASE:
+ t = "gone";
+ break;
+ default:
+ return;
+ }
+
+ if (t && !dbus_message_append_args(m,
+ DBUS_TYPE_UINT32, major(sd->dev),
+ DBUS_TYPE_UINT32, minor(sd->dev),
+ DBUS_TYPE_STRING, &t,
+ DBUS_TYPE_INVALID))
+ return;
+
+ dbus_connection_send(sd->session->manager->bus, m, NULL);
+}
+
+static int sd_eviocrevoke(int fd) {
+ static bool warned;
+ int r;
+
+ assert(fd >= 0);
+
+ r = ioctl(fd, EVIOCREVOKE, 1);
+ if (r < 0) {
+ r = -errno;
+ if (r == -EINVAL && !warned) {
+ warned = true;
+ log_warning("kernel does not support evdev-revocation");
+ }
+ }
+
+ return 0;
+}
+
+static int sd_drmsetmaster(int fd) {
+ int r;
+
+ assert(fd >= 0);
+
+ r = ioctl(fd, DRM_IOCTL_SET_MASTER, 0);
+ if (r < 0)
+ return -errno;
+
+ return 0;
+}
+
+static int sd_drmdropmaster(int fd) {
+ int r;
+
+ assert(fd >= 0);
+
+ r = ioctl(fd, DRM_IOCTL_DROP_MASTER, 0);
+ if (r < 0)
+ return -errno;
+
+ return 0;
+}
+
+static int session_device_open(SessionDevice *sd, bool active) {
+ int fd;
+
+ assert(sd->type != DEVICE_TYPE_UNKNOWN);
+
+ /* open device and try to get an udev_device from it */
+ fd = open(sd->node, O_RDWR|O_CLOEXEC|O_NOCTTY|O_NONBLOCK);
+ if (fd < 0)
+ return -errno;
+
+ switch (sd->type) {
+ case DEVICE_TYPE_DRM:
+ if (active)
+ sd_drmsetmaster(fd);
+ else {
+ /* DRM-Master is granted to the first user who opens a
+ * device automatically (ughh, racy!). Hence, we just
+ * drop DRM-Master in case we were the first. */
+ sd_drmdropmaster(fd);
+ }
+ break;
+ case DEVICE_TYPE_EVDEV:
+ if (!active)
+ sd_eviocrevoke(fd);
+ break;
+ case DEVICE_TYPE_FBDEV:
+ case DEVICE_TYPE_UNKNOWN:
+ default:
+ /* fallback for devices wihout synchronizations */
+ break;
+ }
+
+ return fd;
+}
+
+static int session_device_start(SessionDevice *sd) {
+ int r;
+
+ assert(sd);
+ assert(session_is_active(sd->session));
+
+ if (sd->active)
+ return 0;
+
+ switch (sd->type) {
+ case DEVICE_TYPE_DRM:
+ /* Device is kept open. Simply call drmSetMaster() and hope
+ * there is no-one else. In case it fails, we keep the device
+ * paused. Maybe at some point we have a drmStealMaster(). */
+ r = sd_drmsetmaster(sd->fd);
+ if (r < 0)
+ return r;
+ break;
+ case DEVICE_TYPE_EVDEV:
+ /* Evdev devices are revoked while inactive. Reopen it and we
+ * are fine. */
+ r = session_device_open(sd, true);
+ if (r < 0)
+ return r;
+ close_nointr_nofail(sd->fd);
+ sd->fd = r;
+ break;
+ case DEVICE_TYPE_FBDEV:
+ /* fbdev devices have no way to synchronize access. Moreover,
+ * they mostly operate through mmaps() without any pageflips
+ * and modesetting, so there is no way for us to prevent access
+ * but tear down mmaps.
+ * That would be quite expensive to do on a per-fd context. So
+ * ignore legcy fbdev and let its users feel the pain they asked
+ * for when deciding for fbdev. */
+ case DEVICE_TYPE_UNKNOWN:
+ default:
+ /* fallback for devices wihout synchronizations */
+ break;
+ }
+
+ sd->active = true;
+ return 0;
+}
+
+static void session_device_stop(SessionDevice *sd) {
+ assert(sd);
+
+ if (!sd->active)
+ return;
+
+ switch (sd->type) {
+ case DEVICE_TYPE_DRM:
+ /* On DRM devices we simply drop DRM-Master but keep it open.
+ * This allows the user to keep resources allocated. The
+ * CAP_SYS_ADMIN restriction to DRM-Master prevents users from
+ * circumventing this. */
+ sd_drmdropmaster(sd->fd);
+ break;
+ case DEVICE_TYPE_EVDEV:
+ /* Revoke access on evdev file-descriptors during deactivation.
+ * This will basically prevent any operations on the fd and
+ * cannot be undone. Good side is: it needs no CAP_SYS_ADMIN
+ * protection this way. */
+ sd_eviocrevoke(sd->fd);
+ break;
+ case DEVICE_TYPE_FBDEV:
+ case DEVICE_TYPE_UNKNOWN:
+ default:
+ /* fallback for devices without synchronization */
+ break;
+ }
+
+ sd->active = false;
+}
+
+static DeviceType detect_device_type(struct udev_device *dev) {
+ const char *sysname, *subsystem;
+ DeviceType type;
+
+ sysname = udev_device_get_sysname(dev);
+ subsystem = udev_device_get_subsystem(dev);
+ type = DEVICE_TYPE_UNKNOWN;
+
+ if (streq_ptr(subsystem, "graphics")) {
+ if (!streq(sysname, "fbcon") && startswith(sysname, "fb"))
+ type = DEVICE_TYPE_FBDEV;
+ } else if (streq_ptr(subsystem, "drm")) {
+ if (startswith(sysname, "card"))
+ type = DEVICE_TYPE_DRM;
+ } else if (streq_ptr(subsystem, "input")) {
+ if (startswith(sysname, "event"))
+ type = DEVICE_TYPE_EVDEV;
+ }
+
+ return type;
+}
+
+static int session_device_verify(SessionDevice *sd) {
+ struct udev_device *dev, *p = NULL;
+ const char *sp, *node;
+ int r;
+
+ dev = udev_device_new_from_devnum(sd->session->manager->udev, 'c', sd->dev);
+ if (!dev)
+ return -ENODEV;
+
+ sp = udev_device_get_syspath(dev);
+ node = udev_device_get_devnode(dev);
+ if (!node) {
+ r = -EINVAL;
+ goto err_dev;
+ }
+
+ /* detect device type so we can find the correct sysfs parent */
+ sd->type = detect_device_type(dev);
+ if (sd->type == DEVICE_TYPE_UNKNOWN) {
+ r = -ENODEV;
+ goto err_dev;
+ } else if (sd->type == DEVICE_TYPE_EVDEV) {
+ /* for evdev devices we need the parent node as device */
+ p = dev;
+ dev = udev_device_get_parent_with_subsystem_devtype(p, "input", NULL);
+ if (!dev) {
+ r = -ENODEV;
+ goto err_dev;
+ }
+ sp = udev_device_get_syspath(dev);
+ } else if (sd->type != DEVICE_TYPE_FBDEV &&
+ sd->type != DEVICE_TYPE_DRM) {
+ /* Prevent opening unsupported devices. Especially devices of
+ * subsystem "input" must be opened via the evdev node as
+ * we require EVIOCREVOKE. */
+ r = -ENODEV;
+ goto err_dev;
+ }
+
+ /* search for an existing seat device and return it if available */
+ sd->device = hashmap_get(sd->session->manager->devices, sp);
+ if (!sd->device) {
+ /* The caller might have gotten the udev event before we were
+ * able to process it. Hence, fake the "add" event and let the
+ * logind-manager handle the new device. */
+ r = manager_process_seat_device(sd->session->manager, dev);
+ if (r < 0)
+ goto err_dev;
+
+ /* if it's still not available, then the device is invalid */
+ sd->device = hashmap_get(sd->session->manager->devices, sp);
+ if (!sd->device) {
+ r = -ENODEV;
+ goto err_dev;
+ }
+ }
+
+ if (sd->device->seat != sd->session->seat) {
+ r = -EPERM;
+ goto err_dev;
+ }
+
+ sd->node = strdup(node);
+ if (!sd->node) {
+ r = -ENOMEM;
+ goto err_dev;
+ }
+
+ r = 0;
+err_dev:
+ udev_device_unref(p ? : dev);
+ return r;
+}
+
+int session_device_new(Session *s, dev_t dev, SessionDevice **out) {
+ SessionDevice *sd;
+ int r;
+
+ assert(s);
+ assert(out);
+
+ if (!s->seat)
+ return -EPERM;
+
+ sd = new0(SessionDevice, 1);
+ if (!sd)
+ return -ENOMEM;
+
+ sd->session = s;
+ sd->dev = dev;
+ sd->fd = -1;
+ sd->type = DEVICE_TYPE_UNKNOWN;
+
+ r = session_device_verify(sd);
+ if (r < 0)
+ goto error;
+
+ assert_cc(sizeof(unsigned long) >= sizeof(dev_t));
+
+ r = hashmap_put(s->devices, ULONG_TO_PTR((unsigned long)sd->dev), sd);
+ if (r < 0) {
+ r = -ENOMEM;
+ goto error;
+ }
+
+ /* Open the device for the first time. We need a valid fd to pass back
+ * to the caller. If the session is not active, this _might_ immediately
+ * revoke access and thus invalidate the fd. But this is still needed
+ * to pass a valid fd back. */
+ sd->active = session_is_active(s);
+ sd->fd = session_device_open(sd, sd->active);
+ if (sd->fd < 0)
+ goto error;
+
+ LIST_PREPEND(SessionDevice, sd_by_device, sd->device->session_devices, sd);
+
+ *out = sd;
+ return 0;
+
+error:
+ hashmap_remove(s->devices, ULONG_TO_PTR((unsigned long)sd->dev));
+ free(sd->node);
+ free(sd);
+ return r;
+}
+
+void session_device_free(SessionDevice *sd) {
+ assert(sd);
+
+ session_device_stop(sd);
+ session_device_notify(sd, SESSION_DEVICE_RELEASE);
+ close_nointr_nofail(sd->fd);
+
+ LIST_REMOVE(SessionDevice, sd_by_device, sd->device->session_devices, sd);
+
+ hashmap_remove(sd->session->devices, ULONG_TO_PTR((unsigned long)sd->dev));
+
+ free(sd->node);
+ free(sd);
+}
+
+void session_device_complete_pause(SessionDevice *sd) {
+ if (!sd->active)
+ return;
+
+ session_device_stop(sd);
+}
+
+void session_device_resume_all(Session *s) {
+ SessionDevice *sd;
+ Iterator i;
+ int r;
+
+ assert(s);
+
+ HASHMAP_FOREACH(sd, s->devices, i) {
+ if (!sd->active) {
+ r = session_device_start(sd);
+ if (!r)
+ session_device_notify(sd, SESSION_DEVICE_RESUME);
+ }
+ }
+}
+
+void session_device_pause_all(Session *s) {
+ SessionDevice *sd;
+ Iterator i;
+
+ assert(s);
+
+ HASHMAP_FOREACH(sd, s->devices, i) {
+ if (sd->active) {
+ session_device_stop(sd);
+ session_device_notify(sd, SESSION_DEVICE_PAUSE);
+ }
+ }
+}
~ianmdlvl / elogind.git / blobdiff