--- /dev/null
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+ This file is part of systemd.
+
+ Copyright (C) 2014 David Herrmann <dh.herrmann@gmail.com>
+
+ 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 <fcntl.h>
+#include <inttypes.h>
+#include <libevdev/libevdev.h>
+#include <libudev.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <systemd/sd-bus.h>
+#include <systemd/sd-event.h>
+#include <unistd.h>
+#include "bus-util.h"
+#include "hashmap.h"
+#include "idev.h"
+#include "idev-internal.h"
+#include "macro.h"
+#include "udev-util.h"
+#include "util.h"
+
+typedef struct idev_evdev idev_evdev;
+typedef struct unmanaged_evdev unmanaged_evdev;
+typedef struct managed_evdev managed_evdev;
+
+struct idev_evdev {
+ struct idev_element element;
+ struct libevdev *evdev;
+ int fd;
+ sd_event_source *fd_src;
+ sd_event_source *idle_src;
+
+ bool unsync : 1; /* not in-sync with kernel */
+ bool resync : 1; /* re-syncing with kernel */
+};
+
+struct unmanaged_evdev {
+ struct idev_evdev evdev;
+ char *devnode;
+};
+
+struct managed_evdev {
+ struct idev_evdev evdev;
+ dev_t devnum;
+
+ sd_bus_slot *slot_pause_device;
+ sd_bus_slot *slot_resume_device;
+ sd_bus_slot *slot_take_device;
+
+ bool requested : 1; /* TakeDevice() was sent */
+ bool acquired : 1; /* TakeDevice() was successful */
+};
+
+#define idev_evdev_from_element(_e) container_of((_e), idev_evdev, element)
+#define unmanaged_evdev_from_element(_e) \
+ container_of(idev_evdev_from_element(_e), unmanaged_evdev, evdev)
+#define managed_evdev_from_element(_e) \
+ container_of(idev_evdev_from_element(_e), managed_evdev, evdev)
+
+#define IDEV_EVDEV_INIT(_vtable, _session) ((idev_evdev){ \
+ .element = IDEV_ELEMENT_INIT((_vtable), (_session)), \
+ .fd = -1, \
+ })
+
+#define IDEV_EVDEV_NAME_MAX (8 + DECIMAL_STR_MAX(unsigned) * 2)
+
+static const idev_element_vtable unmanaged_evdev_vtable;
+static const idev_element_vtable managed_evdev_vtable;
+
+static int idev_evdev_resume(idev_evdev *evdev, int dev_fd);
+static void idev_evdev_pause(idev_evdev *evdev, bool release);
+
+/*
+ * Virtual Evdev Element
+ * The virtual evdev element is the base class of all other evdev elements. It
+ * uses libevdev to access the kernel evdev API. It supports asynchronous
+ * access revocation, re-syncing if events got dropped and more.
+ * This element cannot be used by itself. There must be a wrapper around it
+ * which opens a file-descriptor and passes it to the virtual evdev element.
+ */
+
+static void idev_evdev_name(char *out, dev_t devnum) {
+ /* @out must be at least of size IDEV_EVDEV_NAME_MAX */
+ sprintf(out, "evdev/%u:%u", major(devnum), minor(devnum));
+}
+
+static int idev_evdev_raise(idev_evdev *evdev, struct input_event *event) {
+ idev_data data = {
+ .type = IDEV_DATA_EVDEV,
+ .resync = evdev->resync,
+ .evdev = {
+ .event = *event,
+ },
+ };
+
+ return idev_element_feed(&evdev->element, &data);
+}
+
+static void idev_evdev_hup(idev_evdev *evdev) {
+ /*
+ * On HUP, we close the current fd via idev_evdev_pause(). This drops
+ * the event-sources from the main-loop and effectively puts the
+ * element asleep. If the HUP is part of a hotplug-event, a following
+ * udev-notification will destroy the element. Otherwise, the HUP is
+ * either result of access-revokation or a serious error.
+ * For unmanaged devices, we should never receive HUP (except for
+ * unplug-events). But if we do, something went seriously wrong and we
+ * shouldn't try to be clever.
+ * Instead, we simply stay asleep and wait for the device to be
+ * disabled and then re-enabled (or closed and re-opened). This will
+ * re-open the device node and restart the device.
+ * For managed devices, a HUP usually means our device-access was
+ * revoked. In that case, we simply put the device asleep and wait for
+ * logind to notify us once the device is alive again. logind also
+ * passes us a new fd. Hence, we don't have to re-enable the device.
+ *
+ * Long story short: The only thing we have to do here, is close() the
+ * file-descriptor and remove it from the main-loop. Everything else is
+ * handled via additional events we receive.
+ */
+
+ idev_evdev_pause(evdev, true);
+}
+
+static int idev_evdev_io(idev_evdev *evdev) {
+ idev_element *e = &evdev->element;
+ struct input_event ev;
+ unsigned int flags;
+ int r, error = 0;
+
+ /*
+ * Read input-events via libevdev until the input-queue is drained. In
+ * case we're disabled, don't do anything. The input-queue might
+ * overflow, but we don't care as we have to resync after wake-up,
+ * anyway.
+ * TODO: libevdev should give us a hint how many events to read. We
+ * really want to avoid starvation, so we shouldn't read forever in
+ * case we cannot keep up with the kernel.
+ * TODO: Make sure libevdev always reports SYN_DROPPED to us, regardless
+ * whether any event was synced afterwards.
+ * TODO: Forward SYN_DROPPED to attached devices.
+ */
+
+ flags = LIBEVDEV_READ_FLAG_NORMAL;
+ while (e->enabled) {
+ if (evdev->unsync) {
+ /* immediately resync, even if in sync right now */
+ evdev->unsync = false;
+ evdev->resync = false;
+ flags = LIBEVDEV_READ_FLAG_NORMAL;
+ r = libevdev_next_event(evdev->evdev, flags | LIBEVDEV_READ_FLAG_FORCE_SYNC, &ev);
+ if (r < 0 && r != -EAGAIN) {
+ r = 0;
+ goto error;
+ } else if (r != LIBEVDEV_READ_STATUS_SYNC) {
+ log_debug("idev-evdev: %s/%s: cannot force resync: %d",
+ e->session->name, e->name, r);
+ }
+ } else {
+ r = libevdev_next_event(evdev->evdev, flags, &ev);
+ }
+
+ if (evdev->resync && r == -EAGAIN) {
+ /* end of re-sync */
+ evdev->resync = false;
+ flags = LIBEVDEV_READ_FLAG_NORMAL;
+ } else if (r == -EAGAIN) {
+ /* no data available */
+ break;
+ } else if (r < 0) {
+ /* read error */
+ goto error;
+ } else if (r == LIBEVDEV_READ_STATUS_SYNC) {
+ if (evdev->resync) {
+ /* sync-event */
+ r = idev_evdev_raise(evdev, &ev);
+ if (r != 0) {
+ error = r;
+ break;
+ }
+ } else {
+ /* start of sync */
+ evdev->resync = true;
+ flags = LIBEVDEV_READ_FLAG_SYNC;
+ }
+ } else {
+ /* normal event */
+ r = idev_evdev_raise(evdev, &ev);
+ if (r != 0) {
+ error = r;
+ break;
+ }
+ }
+ }
+
+ if (error < 0)
+ log_debug("idev-evdev: %s/%s: error on data event: %s",
+ e->session->name, e->name, strerror(-error));
+ return error;
+
+error:
+ idev_evdev_hup(evdev);
+ return r;
+}
+
+static int idev_evdev_event_fn(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
+ idev_evdev *evdev = userdata;
+
+ /* fetch data as long as EPOLLIN is signalled */
+ if (revents & EPOLLIN)
+ return idev_evdev_io(evdev);
+
+ if (revents & (EPOLLHUP | EPOLLERR))
+ idev_evdev_hup(evdev);
+
+ return 0;
+}
+
+static int idev_evdev_idle_fn(sd_event_source *s, void *userdata) {
+ idev_evdev *evdev = userdata;
+
+ /*
+ * The idle-event is raised whenever we have to re-sync the libevdev
+ * state from the kernel. We simply call into idev_evdev_io() which
+ * flushes the state and re-syncs it if @unsync is set.
+ * State has to be synced whenever our view of the kernel device is
+ * out of date. This is the case when we open the device, if the
+ * kernel's receive buffer overflows, or on other exceptional
+ * situations. Events during re-syncs must be forwarded to the upper
+ * layers so they can update their view of the device. However, such
+ * events must only be handled passively, as they might be out-of-order
+ * and/or re-ordered. Therefore, we mark them as 'sync' events.
+ */
+
+ if (!evdev->unsync)
+ return 0;
+
+ return idev_evdev_io(evdev);
+}
+
+static void idev_evdev_destroy(idev_evdev *evdev) {
+ assert(evdev);
+ assert(evdev->fd < 0);
+
+ libevdev_free(evdev->evdev);
+ evdev->evdev = NULL;
+}
+
+static void idev_evdev_enable(idev_evdev *evdev) {
+ assert(evdev);
+ assert(evdev->fd_src);
+ assert(evdev->idle_src);
+
+ sd_event_source_set_enabled(evdev->fd_src, SD_EVENT_ON);
+ sd_event_source_set_enabled(evdev->idle_src, SD_EVENT_ONESHOT);
+}
+
+static void idev_evdev_disable(idev_evdev *evdev) {
+ assert(evdev);
+ assert(evdev->fd_src);
+ assert(evdev->idle_src);
+
+ sd_event_source_set_enabled(evdev->fd_src, SD_EVENT_OFF);
+ sd_event_source_set_enabled(evdev->idle_src, SD_EVENT_OFF);
+}
+
+static int idev_evdev_resume(idev_evdev *evdev, int dev_fd) {
+ idev_element *e = &evdev->element;
+ _cleanup_close_ int fd = dev_fd;
+ int r, flags;
+
+ if (fd < 0 || evdev->fd == fd) {
+ fd = -1;
+ if (evdev->fd >= 0 && e->n_open > 0 && e->enabled)
+ idev_evdev_enable(evdev);
+
+ return 0;
+ }
+
+ idev_evdev_pause(evdev, true);
+ log_debug("idev-evdev: %s/%s: resume", e->session->name, e->name);
+
+ r = fd_nonblock(fd, true);
+ if (r < 0)
+ return r;
+
+ r = fd_cloexec(fd, true);
+ if (r < 0)
+ return r;
+
+ flags = fcntl(fd, F_GETFL, 0);
+ if (flags < 0)
+ return r;
+
+ flags &= O_ACCMODE;
+ if (flags == O_WRONLY)
+ return -EACCES;
+
+ evdev->element.readable = true;
+ evdev->element.writable = true;
+ if (flags == O_RDONLY)
+ evdev->element.writable = false;
+ else if (flags == O_WRONLY)
+ evdev->element.readable = false;
+
+ /*
+ * TODO: We *MUST* re-sync the device so we get a delta of the changed
+ * state while we didn't read events from the device. This works just
+ * fine with libevdev_change_fd(), however, libevdev_new_from_fd() (or
+ * libevdev_set_fd()) don't pass us events for the initial device
+ * state. So even if we force a re-sync, we will not get the delta for
+ * the initial device state.
+ * We really need to fix libevdev to support that!
+ */
+ if (evdev->evdev)
+ r = libevdev_change_fd(evdev->evdev, fd);
+ else
+ r = libevdev_new_from_fd(fd, &evdev->evdev);
+
+ if (r < 0)
+ return r;
+
+ r = sd_event_add_io(e->session->context->event,
+ &evdev->fd_src,
+ fd,
+ EPOLLHUP | EPOLLERR | EPOLLIN,
+ idev_evdev_event_fn,
+ evdev);
+ if (r < 0)
+ return r;
+
+ r = sd_event_add_defer(e->session->context->event,
+ &evdev->idle_src,
+ idev_evdev_idle_fn,
+ evdev);
+ if (r < 0) {
+ evdev->fd_src = sd_event_source_unref(evdev->fd_src);
+ return r;
+ }
+
+ if (e->n_open < 1 || !e->enabled) {
+ sd_event_source_set_enabled(evdev->fd_src, SD_EVENT_OFF);
+ sd_event_source_set_enabled(evdev->idle_src, SD_EVENT_OFF);
+ }
+
+ evdev->unsync = true;
+ evdev->fd = fd;
+
+ fd = -1;
+ return 0;
+}
+
+static void idev_evdev_pause(idev_evdev *evdev, bool release) {
+ idev_element *e = &evdev->element;
+
+ if (evdev->fd < 0)
+ return;
+
+ log_debug("idev-evdev: %s/%s: pause", e->session->name, e->name);
+
+ if (release) {
+ evdev->idle_src = sd_event_source_unref(evdev->idle_src);
+ evdev->fd_src = sd_event_source_unref(evdev->fd_src);
+ evdev->fd = safe_close(evdev->fd);
+ } else {
+ idev_evdev_disable(evdev);
+ }
+}
+
+/*
+ * Unmanaged Evdev Element
+ * The unmanaged evdev element opens the evdev node for a given input device
+ * directly (/dev/input/eventX) and thus needs sufficient privileges. It opens
+ * the device only if we really require it and releases it as soon as we're
+ * disabled or closed.
+ * The unmanaged element can be used in all situations where you have direct
+ * access to input device nodes. Unlike managed evdev elements, it can be used
+ * outside of user sessions and in emergency situations where logind is not
+ * available.
+ */
+
+static void unmanaged_evdev_resume(idev_element *e) {
+ unmanaged_evdev *eu = unmanaged_evdev_from_element(e);
+ int r, fd;
+
+ /*
+ * Unmanaged devices can be acquired on-demand. Therefore, don't
+ * acquire it unless someone opened the device *and* we're enabled.
+ */
+ if (e->n_open < 1 || !e->enabled)
+ return;
+
+ fd = eu->evdev.fd;
+ if (fd < 0) {
+ fd = open(eu->devnode, O_RDWR | O_CLOEXEC | O_NOCTTY | O_NONBLOCK);
+ if (fd < 0) {
+ if (errno != EACCES && errno != EPERM) {
+ log_debug("idev-evdev: %s/%s: cannot open node %s: %m",
+ e->session->name, e->name, eu->devnode);
+ return;
+ }
+
+ fd = open(eu->devnode, O_RDONLY | O_CLOEXEC | O_NOCTTY | O_NONBLOCK);
+ if (fd < 0) {
+ log_debug("idev-evdev: %s/%s: cannot open node %s: %m",
+ e->session->name, e->name, eu->devnode);
+ return;
+ }
+
+ e->readable = true;
+ e->writable = false;
+ } else {
+ e->readable = true;
+ e->writable = true;
+ }
+ }
+
+ r = idev_evdev_resume(&eu->evdev, fd);
+ if (r < 0)
+ log_debug("idev-evdev: %s/%s: cannot resume: %s",
+ e->session->name, e->name, strerror(-r));
+}
+
+static void unmanaged_evdev_pause(idev_element *e) {
+ unmanaged_evdev *eu = unmanaged_evdev_from_element(e);
+
+ /*
+ * Release the device if the device is disabled or there is no-one who
+ * opened it. This guarantees we stay only available if we're opened
+ * *and* enabled.
+ */
+
+ idev_evdev_pause(&eu->evdev, true);
+}
+
+static int unmanaged_evdev_new(idev_element **out, idev_session *s, struct udev_device *ud) {
+ _cleanup_(idev_element_freep) idev_element *e = NULL;
+ char name[IDEV_EVDEV_NAME_MAX];
+ unmanaged_evdev *eu;
+ const char *devnode;
+ dev_t devnum;
+ int r;
+
+ assert_return(s, -EINVAL);
+ assert_return(ud, -EINVAL);
+
+ devnode = udev_device_get_devnode(ud);
+ devnum = udev_device_get_devnum(ud);
+ if (!devnode || devnum == 0)
+ return -ENODEV;
+
+ idev_evdev_name(name, devnum);
+
+ eu = new0(unmanaged_evdev, 1);
+ if (!eu)
+ return -ENOMEM;
+
+ e = &eu->evdev.element;
+ eu->evdev = IDEV_EVDEV_INIT(&unmanaged_evdev_vtable, s);
+
+ eu->devnode = strdup(devnode);
+ if (!eu->devnode)
+ return -ENOMEM;
+
+ r = idev_element_add(e, name);
+ if (r < 0)
+ return r;
+
+ if (out)
+ *out = e;
+ e = NULL;
+ return 0;
+}
+
+static void unmanaged_evdev_free(idev_element *e) {
+ unmanaged_evdev *eu = unmanaged_evdev_from_element(e);
+
+ idev_evdev_destroy(&eu->evdev);
+ free(eu->devnode);
+ free(eu);
+}
+
+static const idev_element_vtable unmanaged_evdev_vtable = {
+ .free = unmanaged_evdev_free,
+ .enable = unmanaged_evdev_resume,
+ .disable = unmanaged_evdev_pause,
+ .open = unmanaged_evdev_resume,
+ .close = unmanaged_evdev_pause,
+};
+
+/*
+ * Managed Evdev Element
+ * The managed evdev element uses systemd-logind to acquire evdev devices. This
+ * means, we do not open the device node /dev/input/eventX directly. Instead,
+ * logind passes us a file-descriptor whenever our session is activated. Thus,
+ * we don't need access to the device node directly.
+ * Furthermore, whenever the session is put asleep, logind revokes the
+ * file-descriptor so we loose access to the device.
+ * Managed evdev elements should be preferred over unmanaged elements whenever
+ * you run inside a user session with exclusive device access.
+ */
+
+static int managed_evdev_take_device_fn(sd_bus *bus,
+ sd_bus_message *reply,
+ void *userdata,
+ sd_bus_error *ret_error) {
+ managed_evdev *em = userdata;
+ idev_element *e = &em->evdev.element;
+ idev_session *s = e->session;
+ int r, paused, fd;
+
+ em->slot_take_device = sd_bus_slot_unref(em->slot_take_device);
+
+ if (sd_bus_message_is_method_error(reply, NULL)) {
+ const sd_bus_error *error = sd_bus_message_get_error(reply);
+
+ log_debug("idev-evdev: %s/%s: TakeDevice failed: %s: %s",
+ s->name, e->name, error->name, error->message);
+ return 0;
+ }
+
+ em->acquired = true;
+
+ r = sd_bus_message_read(reply, "hb", &fd, &paused);
+ if (r < 0) {
+ log_debug("idev-evdev: %s/%s: erroneous TakeDevice reply", s->name, e->name);
+ return 0;
+ }
+
+ /* If the device is paused, ignore it; we will get the next fd via
+ * ResumeDevice signals. */
+ if (paused)
+ return 0;
+
+ fd = fcntl(fd, F_DUPFD_CLOEXEC, 3);
+ if (fd < 0) {
+ log_debug("idev-evdev: %s/%s: cannot duplicate evdev fd: %m", s->name, e->name);
+ return 0;
+ }
+
+ r = idev_evdev_resume(&em->evdev, fd);
+ if (r < 0)
+ log_debug("idev-evdev: %s/%s: cannot resume: %s",
+ s->name, e->name, strerror(-r));
+
+ return 0;
+}
+
+static void managed_evdev_resume(idev_element *e) {
+ _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
+ managed_evdev *em = managed_evdev_from_element(e);
+ idev_session *s = e->session;
+ idev_context *c = s->context;
+ int r;
+
+ /*
+ * Acquiring managed devices is heavy, so do it only once we're
+ * enabled *and* opened by someone.
+ */
+ if (e->n_open < 1 || !e->enabled)
+ return;
+
+ /* bail out if already pending */
+ if (em->requested)
+ return;
+
+ r = sd_bus_message_new_method_call(c->sysbus,
+ &m,
+ "org.freedesktop.login1",
+ s->path,
+ "org.freedesktop.login1.Session",
+ "TakeDevice");
+ if (r < 0)
+ goto error;
+
+ r = sd_bus_message_append(m, "uu", major(em->devnum), minor(em->devnum));
+ if (r < 0)
+ goto error;
+
+ r = sd_bus_call_async(c->sysbus,
+ &em->slot_take_device,
+ m,
+ managed_evdev_take_device_fn,
+ em,
+ 0);
+ if (r < 0)
+ goto error;
+
+ em->requested = true;
+ return;
+
+error:
+ log_debug("idev-evdev: %s/%s: cannot send TakeDevice request: %s",
+ s->name, e->name, strerror(-r));
+}
+
+static void managed_evdev_pause(idev_element *e) {
+ _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
+ managed_evdev *em = managed_evdev_from_element(e);
+ idev_session *s = e->session;
+ idev_context *c = s->context;
+ int r;
+
+ /*
+ * Releasing managed devices is heavy. Once acquired, we get
+ * notifications for sleep/wake-up events, so there's no reason to
+ * release it if disabled but opened. However, if a device is closed,
+ * we release it immediately as we don't care for sleep/wake-up events
+ * then (even if we're actually enabled).
+ */
+
+ idev_evdev_pause(&em->evdev, false);
+
+ if (e->n_open > 0 || !em->requested)
+ return;
+
+ /*
+ * If TakeDevice() is pending or was successful, make sure to
+ * release the device again. We don't care for return-values,
+ * so send it without waiting or callbacks.
+ * If a failed TakeDevice() is pending, but someone else took
+ * the device on the same bus-connection, we might incorrectly
+ * release their device. This is an unlikely race, though.
+ * Furthermore, you really shouldn't have two users of the
+ * controller-API on the same session, on the same devices, *AND* on
+ * the same bus-connection. So we don't care for that race..
+ */
+
+ idev_evdev_pause(&em->evdev, true);
+ em->requested = false;
+
+ if (!em->acquired && !em->slot_take_device)
+ return;
+
+ em->slot_take_device = sd_bus_slot_unref(em->slot_take_device);
+ em->acquired = false;
+
+ r = sd_bus_message_new_method_call(c->sysbus,
+ &m,
+ "org.freedesktop.login1",
+ s->path,
+ "org.freedesktop.login1.Session",
+ "ReleaseDevice");
+ if (r >= 0) {
+ r = sd_bus_message_append(m, "uu", major(em->devnum), minor(em->devnum));
+ if (r >= 0)
+ r = sd_bus_send(c->sysbus, m, NULL);
+ }
+
+ if (r < 0 && r != -ENOTCONN)
+ log_debug("idev-evdev: %s/%s: cannot send ReleaseDevice: %s",
+ s->name, e->name, strerror(-r));
+}
+
+static int managed_evdev_pause_device_fn(sd_bus *bus,
+ sd_bus_message *signal,
+ void *userdata,
+ sd_bus_error *ret_error) {
+ managed_evdev *em = userdata;
+ idev_element *e = &em->evdev.element;
+ idev_session *s = e->session;
+ idev_context *c = s->context;
+ uint32_t major, minor;
+ const char *mode;
+ int r;
+
+ /*
+ * We get PauseDevice() signals from logind whenever a device we
+ * requested was, or is about to be, paused. Arguments are major/minor
+ * number of the device and the mode of the operation.
+ * In case the event is not about our device, we ignore it. Otherwise,
+ * we treat it as asynchronous access-revocation (as if we got HUP on
+ * the device fd). Note that we might have already treated the HUP
+ * event via EPOLLHUP, whichever comes first.
+ *
+ * @mode can be one of the following:
+ * "pause": The device is about to be paused. We must react
+ * immediately and respond with PauseDeviceComplete(). Once
+ * we replied, logind will pause the device. Note that
+ * logind might apply any kind of timeout and force pause
+ * the device if we don't respond in a timely manner. In
+ * this case, we will receive a second PauseDevice event
+ * with @mode set to "force" (or similar).
+ * "force": The device was disabled forecfully by logind. Access is
+ * already revoked. This is just an asynchronous
+ * notification so we can put the device asleep (in case
+ * we didn't already notice the access revocation).
+ * "gone": This is like "force" but is sent if the device was
+ * paused due to a device-removal event.
+ *
+ * We always handle PauseDevice signals as "force" as we properly
+ * support asynchronous access revocation, anyway. But in case logind
+ * sent mode "pause", we also call PauseDeviceComplete() to immediately
+ * acknowledge the request.
+ */
+
+ r = sd_bus_message_read(signal, "uus", &major, &minor, &mode);
+ if (r < 0) {
+ log_debug("idev-evdev: %s/%s: erroneous PauseDevice signal",
+ s->name, e->name);
+ return 0;
+ }
+
+ /* not our device? */
+ if (makedev(major, minor) != em->devnum)
+ return 0;
+
+ idev_evdev_pause(&em->evdev, true);
+
+ if (streq(mode, "pause")) {
+ _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
+
+ /*
+ * Sending PauseDeviceComplete() is racy if logind triggers the
+ * timeout. That is, if we take too long and logind pauses the
+ * device by sending a forced PauseDevice, our
+ * PauseDeviceComplete call will be stray. That's fine, though.
+ * logind ignores such stray calls. Only if logind also sent a
+ * further PauseDevice() signal, it might match our call
+ * incorrectly to the newer PauseDevice(). That's fine, too, as
+ * we handle that event asynchronously, anyway. Therefore,
+ * whatever happens, we're fine. Yay!
+ */
+
+ r = sd_bus_message_new_method_call(c->sysbus,
+ &m,
+ "org.freedesktop.login1",
+ s->path,
+ "org.freedesktop.login1.Session",
+ "PauseDeviceComplete");
+ if (r >= 0) {
+ r = sd_bus_message_append(m, "uu", major, minor);
+ if (r >= 0)
+ r = sd_bus_send(c->sysbus, m, NULL);
+ }
+
+ if (r < 0)
+ log_debug("idev-evdev: %s/%s: cannot send PauseDeviceComplete: %s",
+ s->name, e->name, strerror(-r));
+ }
+
+ return 0;
+}
+
+static int managed_evdev_resume_device_fn(sd_bus *bus,
+ sd_bus_message *signal,
+ void *userdata,
+ sd_bus_error *ret_error) {
+ managed_evdev *em = userdata;
+ idev_element *e = &em->evdev.element;
+ idev_session *s = e->session;
+ uint32_t major, minor;
+ int r, fd;
+
+ /*
+ * We get ResumeDevice signals whenever logind resumed a previously
+ * paused device. The arguments contain the major/minor number of the
+ * related device and a new file-descriptor for the freshly opened
+ * device-node.
+ * If the signal is not about our device, we simply ignore it.
+ * Otherwise, we take the file-descriptor and immediately resume the
+ * device.
+ */
+
+ r = sd_bus_message_read(signal, "uuh", &major, &minor, &fd);
+ if (r < 0) {
+ log_debug("idev-evdev: %s/%s: erroneous ResumeDevice signal",
+ s->name, e->name);
+ return 0;
+ }
+
+ /* not our device? */
+ if (makedev(major, minor) != em->devnum)
+ return 0;
+
+ fd = fcntl(fd, F_DUPFD_CLOEXEC, 3);
+ if (fd < 0) {
+ log_debug("idev-evdev: %s/%s: cannot duplicate evdev fd: %m",
+ s->name, e->name);
+ return 0;
+ }
+
+ r = idev_evdev_resume(&em->evdev, fd);
+ if (r < 0)
+ log_debug("idev-evdev: %s/%s: cannot resume: %s",
+ s->name, e->name, strerror(-r));
+
+ return 0;
+}
+
+static int managed_evdev_setup_bus(managed_evdev *em) {
+ idev_element *e = &em->evdev.element;
+ idev_session *s = e->session;
+ idev_context *c = s->context;
+ _cleanup_free_ char *match = NULL;
+ int r;
+
+ match = strjoin("type='signal',"
+ "sender='org.freedesktop.login1',"
+ "interface='org.freedesktop.login1.Session',"
+ "member='PauseDevice',"
+ "path='", s->path, "'",
+ NULL);
+ if (!match)
+ return -ENOMEM;
+
+ r = sd_bus_add_match(c->sysbus,
+ &em->slot_pause_device,
+ match,
+ managed_evdev_pause_device_fn,
+ em);
+ if (r < 0)
+ return r;
+
+ free(match);
+ match = strjoin("type='signal',"
+ "sender='org.freedesktop.login1',"
+ "interface='org.freedesktop.login1.Session',"
+ "member='ResumeDevice',"
+ "path='", s->path, "'",
+ NULL);
+ if (!match)
+ return -ENOMEM;
+
+ r = sd_bus_add_match(c->sysbus,
+ &em->slot_resume_device,
+ match,
+ managed_evdev_resume_device_fn,
+ em);
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
+static int managed_evdev_new(idev_element **out, idev_session *s, struct udev_device *ud) {
+ _cleanup_(idev_element_freep) idev_element *e = NULL;
+ char name[IDEV_EVDEV_NAME_MAX];
+ managed_evdev *em;
+ dev_t devnum;
+ int r;
+
+ assert_return(s, -EINVAL);
+ assert_return(s->context->sysbus, -EINVAL);
+ assert_return(s->managed, -EINVAL);
+ assert_return(s->context->sysbus, -EINVAL);
+ assert_return(ud, -EINVAL);
+
+ devnum = udev_device_get_devnum(ud);
+ if (devnum == 0)
+ return -ENODEV;
+
+ idev_evdev_name(name, devnum);
+
+ em = new0(managed_evdev, 1);
+ if (!em)
+ return -ENOMEM;
+
+ e = &em->evdev.element;
+ em->evdev = IDEV_EVDEV_INIT(&managed_evdev_vtable, s);
+ em->devnum = devnum;
+
+ r = managed_evdev_setup_bus(em);
+ if (r < 0)
+ return r;
+
+ r = idev_element_add(e, name);
+ if (r < 0)
+ return r;
+
+ if (out)
+ *out = e;
+ e = NULL;
+ return 0;
+}
+
+static void managed_evdev_free(idev_element *e) {
+ managed_evdev *em = managed_evdev_from_element(e);
+
+ em->slot_resume_device = sd_bus_slot_unref(em->slot_resume_device);
+ em->slot_pause_device = sd_bus_slot_unref(em->slot_pause_device);
+ idev_evdev_destroy(&em->evdev);
+ free(em);
+}
+
+static const idev_element_vtable managed_evdev_vtable = {
+ .free = managed_evdev_free,
+ .enable = managed_evdev_resume,
+ .disable = managed_evdev_pause,
+ .open = managed_evdev_resume,
+ .close = managed_evdev_pause,
+};
+
+/*
+ * Generic Constructor
+ * Instead of relying on the caller to choose between managed and unmanaged
+ * evdev devices, the idev_evdev_new() constructor does that for you (by
+ * looking at s->managed).
+ */
+
+bool idev_is_evdev(idev_element *e) {
+ return e && (e->vtable == &unmanaged_evdev_vtable ||
+ e->vtable == &managed_evdev_vtable);
+}
+
+idev_element *idev_find_evdev(idev_session *s, dev_t devnum) {
+ char name[IDEV_EVDEV_NAME_MAX];
+
+ assert_return(s, NULL);
+ assert_return(devnum != 0, NULL);
+
+ idev_evdev_name(name, devnum);
+ return idev_find_element(s, name);
+}
+
+int idev_evdev_new(idev_element **out, idev_session *s, struct udev_device *ud) {
+ assert_return(s, -EINVAL);
+ assert_return(ud, -EINVAL);
+
+ return s->managed ? managed_evdev_new(out, s, ud) : unmanaged_evdev_new(out, s, ud);
+}
~ianmdlvl / elogind.git / commitdiff