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-rw-r--r--src/login/logind-session-device.c501
1 files changed, 501 insertions, 0 deletions
diff --git a/src/login/logind-session-device.c b/src/login/logind-session-device.c
new file mode 100644
index 0000000..4f934dd
--- /dev/null
+++ b/src/login/logind-session-device.c
@@ -0,0 +1,501 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <fcntl.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+
+#include "sd-device.h"
+#include "sd-daemon.h"
+
+#include "alloc-util.h"
+#include "bus-util.h"
+#include "daemon-util.h"
+#include "fd-util.h"
+#include "logind-session-dbus.h"
+#include "logind-session-device.h"
+#include "missing_drm.h"
+#include "missing_input.h"
+#include "parse-util.h"
+#include "util.h"
+
+enum SessionDeviceNotifications {
+ SESSION_DEVICE_RESUME,
+ SESSION_DEVICE_TRY_PAUSE,
+ SESSION_DEVICE_PAUSE,
+ SESSION_DEVICE_RELEASE,
+};
+
+static int session_device_notify(SessionDevice *sd, enum SessionDeviceNotifications type) {
+ _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+ _cleanup_free_ char *path = NULL;
+ const char *t = NULL;
+ uint32_t major, minor;
+ int r;
+
+ assert(sd);
+
+ major = major(sd->dev);
+ minor = minor(sd->dev);
+
+ if (!sd->session->controller)
+ return 0;
+
+ path = session_bus_path(sd->session);
+ if (!path)
+ return -ENOMEM;
+
+ r = sd_bus_message_new_signal(
+ sd->session->manager->bus,
+ &m, path,
+ "org.freedesktop.login1.Session",
+ type == SESSION_DEVICE_RESUME ? "ResumeDevice" : "PauseDevice");
+ if (!m)
+ return r;
+
+ r = sd_bus_message_set_destination(m, sd->session->controller);
+ if (r < 0)
+ return r;
+
+ switch (type) {
+
+ case SESSION_DEVICE_RESUME:
+ r = sd_bus_message_append(m, "uuh", major, minor, sd->fd);
+ if (r < 0)
+ return r;
+ 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 -EINVAL;
+ }
+
+ if (t) {
+ r = sd_bus_message_append(m, "uus", major, minor, t);
+ if (r < 0)
+ return r;
+ }
+
+ return sd_bus_send(sd->session->manager->bus, m, NULL);
+}
+
+static void sd_eviocrevoke(int fd) {
+ static bool warned = false;
+
+ assert(fd >= 0);
+
+ if (ioctl(fd, EVIOCREVOKE, NULL) < 0) {
+
+ if (errno == EINVAL && !warned) {
+ log_warning_errno(errno, "Kernel does not support evdev-revocation: %m");
+ warned = true;
+ }
+ }
+}
+
+static int sd_drmsetmaster(int fd) {
+ assert(fd >= 0);
+ return RET_NERRNO(ioctl(fd, DRM_IOCTL_SET_MASTER, 0));
+}
+
+static int sd_drmdropmaster(int fd) {
+ assert(fd >= 0);
+ return RET_NERRNO(ioctl(fd, DRM_IOCTL_DROP_MASTER, 0));
+}
+
+static int session_device_open(SessionDevice *sd, bool active) {
+ int fd, r;
+
+ assert(sd);
+ assert(sd->type != DEVICE_TYPE_UNKNOWN);
+ assert(sd->node);
+
+ /* open device and try to get a 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) {
+ /* Weird legacy DRM semantics might return an error even though we're master. No way to detect
+ * that so fail at all times and let caller retry in inactive state. */
+ r = sd_drmsetmaster(fd);
+ if (r < 0) {
+ (void) close_nointr(fd);
+ return r;
+ }
+ } 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. */
+ (void) sd_drmdropmaster(fd);
+ break;
+
+ case DEVICE_TYPE_EVDEV:
+ if (!active)
+ sd_eviocrevoke(fd);
+ break;
+
+ case DEVICE_TYPE_UNKNOWN:
+ default:
+ /* fallback for devices without 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:
+ if (sd->fd < 0)
+ return log_error_errno(SYNTHETIC_ERRNO(EBADF),
+ "Failed to re-activate DRM fd, as the fd was lost (maybe logind restart went wrong?)");
+
+ /* 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;
+
+ /* For evdev devices, the file descriptor might be left uninitialized. This might happen while resuming
+ * into a session and logind has been restarted right before. */
+ close_and_replace(sd->fd, r);
+ break;
+
+ case DEVICE_TYPE_UNKNOWN:
+ default:
+ /* fallback for devices without 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:
+ if (sd->fd < 0) {
+ log_error("Failed to de-activate DRM fd, as the fd was lost (maybe logind restart went wrong?)");
+ return;
+ }
+
+ /* 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_UNKNOWN:
+ default:
+ /* fallback for devices without synchronization */
+ break;
+ }
+
+ sd->active = false;
+}
+
+static DeviceType detect_device_type(sd_device *dev) {
+ const char *sysname, *subsystem;
+ DeviceType type = DEVICE_TYPE_UNKNOWN;
+
+ if (sd_device_get_sysname(dev, &sysname) < 0 ||
+ sd_device_get_subsystem(dev, &subsystem) < 0)
+ return type;
+
+ if (streq(subsystem, "drm")) {
+ if (startswith(sysname, "card"))
+ type = DEVICE_TYPE_DRM;
+ } else if (streq(subsystem, "input")) {
+ if (startswith(sysname, "event"))
+ type = DEVICE_TYPE_EVDEV;
+ }
+
+ return type;
+}
+
+static int session_device_verify(SessionDevice *sd) {
+ _cleanup_(sd_device_unrefp) sd_device *p = NULL;
+ const char *sp, *node;
+ sd_device *dev;
+ int r;
+
+ r = sd_device_new_from_devnum(&p, 'c', sd->dev);
+ if (r < 0)
+ return r;
+
+ dev = p;
+
+ if (sd_device_get_syspath(dev, &sp) < 0 ||
+ sd_device_get_devname(dev, &node) < 0)
+ return -EINVAL;
+
+ /* detect device type so we can find the correct sysfs parent */
+ sd->type = detect_device_type(dev);
+ if (sd->type == DEVICE_TYPE_UNKNOWN)
+ return -ENODEV;
+
+ else if (sd->type == DEVICE_TYPE_EVDEV) {
+ /* for evdev devices we need the parent node as device */
+ if (sd_device_get_parent_with_subsystem_devtype(p, "input", NULL, &dev) < 0)
+ return -ENODEV;
+ if (sd_device_get_syspath(dev, &sp) < 0)
+ return -ENODEV;
+
+ } else if (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. */
+ return -ENODEV;
+
+ /* 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)
+ return r;
+
+ /* if it's still not available, then the device is invalid */
+ sd->device = hashmap_get(sd->session->manager->devices, sp);
+ if (!sd->device)
+ return -ENODEV;
+ }
+
+ if (sd->device->seat != sd->session->seat)
+ return -EPERM;
+
+ sd->node = strdup(node);
+ if (!sd->node)
+ return -ENOMEM;
+
+ return 0;
+}
+
+int session_device_new(Session *s, dev_t dev, bool open_device, 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;
+
+ r = hashmap_put(s->devices, &sd->dev, sd);
+ if (r < 0)
+ goto error;
+
+ if (open_device) {
+ /* 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);
+ r = session_device_open(sd, sd->active);
+ if (r < 0) {
+ /* EINVAL _may_ mean a master is active; retry inactive */
+ if (sd->active && r == -EINVAL) {
+ sd->active = false;
+ r = session_device_open(sd, false);
+ }
+ if (r < 0)
+ goto error;
+ }
+ sd->fd = r;
+ }
+
+ LIST_PREPEND(sd_by_device, sd->device->session_devices, sd);
+
+ *out = sd;
+ return 0;
+
+error:
+ hashmap_remove(s->devices, &sd->dev);
+ free(sd->node);
+ free(sd);
+ return r;
+}
+
+void session_device_free(SessionDevice *sd) {
+ assert(sd);
+
+ /* Make sure to remove the pushed fd. */
+ if (sd->pushed_fd)
+ (void) notify_remove_fd_warnf("session-%s-device-%u-%u", sd->session->id, major(sd->dev), minor(sd->dev));
+
+ session_device_stop(sd);
+ session_device_notify(sd, SESSION_DEVICE_RELEASE);
+ safe_close(sd->fd);
+
+ LIST_REMOVE(sd_by_device, sd->device->session_devices, sd);
+
+ hashmap_remove(sd->session->devices, &sd->dev);
+
+ free(sd->node);
+ free(sd);
+}
+
+void session_device_complete_pause(SessionDevice *sd) {
+ SessionDevice *iter;
+
+ if (!sd->active)
+ return;
+
+ session_device_stop(sd);
+
+ /* if not all devices are paused, wait for further completion events */
+ HASHMAP_FOREACH(iter, sd->session->devices)
+ if (iter->active)
+ return;
+
+ /* complete any pending session switch */
+ seat_complete_switch(sd->session->seat);
+}
+
+void session_device_resume_all(Session *s) {
+ SessionDevice *sd;
+
+ assert(s);
+
+ HASHMAP_FOREACH(sd, s->devices) {
+ if (sd->active)
+ continue;
+
+ if (session_device_start(sd) < 0)
+ continue;
+ if (session_device_save(sd) < 0)
+ continue;
+
+ session_device_notify(sd, SESSION_DEVICE_RESUME);
+ }
+}
+
+void session_device_pause_all(Session *s) {
+ SessionDevice *sd;
+
+ assert(s);
+
+ HASHMAP_FOREACH(sd, s->devices) {
+ if (!sd->active)
+ continue;
+
+ session_device_stop(sd);
+ session_device_notify(sd, SESSION_DEVICE_PAUSE);
+ }
+}
+
+unsigned session_device_try_pause_all(Session *s) {
+ unsigned num_pending = 0;
+ SessionDevice *sd;
+
+ assert(s);
+
+ HASHMAP_FOREACH(sd, s->devices) {
+ if (!sd->active)
+ continue;
+
+ session_device_notify(sd, SESSION_DEVICE_TRY_PAUSE);
+ num_pending++;
+ }
+
+ return num_pending;
+}
+
+int session_device_save(SessionDevice *sd) {
+ const char *id;
+ int r;
+
+ assert(sd);
+
+ /* Store device fd in PID1. It will send it back to us on restart so revocation will continue to work. To make
+ * things simple, send fds for all type of devices even if they don't support the revocation mechanism so we
+ * don't have to handle them differently later.
+ *
+ * Note: for device supporting revocation, PID1 will drop a stored fd automatically if the corresponding device
+ * is revoked. */
+
+ if (sd->pushed_fd)
+ return 0;
+
+ /* Session ID does not contain separators. */
+ id = sd->session->id;
+ assert(*(id + strcspn(id, "-\n")) == '\0');
+
+ r = notify_push_fdf(sd->fd, "session-%s-device-%u-%u", id, major(sd->dev), minor(sd->dev));
+ if (r < 0)
+ return r;
+
+ sd->pushed_fd = true;
+ return 1;
+}
+
+void session_device_attach_fd(SessionDevice *sd, int fd, bool active) {
+ assert(fd >= 0);
+ assert(sd);
+ assert(sd->fd < 0);
+ assert(!sd->active);
+
+ sd->fd = fd;
+ sd->pushed_fd = true;
+ sd->active = active;
+}
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