Adding upstream version 255.4.upstream/255.4

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 507 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..44d8d52
--- /dev/null
+++ b/src/login/logind-session-device.c
@@ -0,0 +1,507 @@
+/* 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"
+
+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);
+
+        /* Prevent opening unsupported devices. Especially devices of
+         * subsystem "input" must be opened via the evdev node as
+         * we require EVIOCREVOKE. */
+        switch (sd->type) {
+        case 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;
+                break;
+
+        case DEVICE_TYPE_DRM:
+                break;
+
+        case  DEVICE_TYPE_UNKNOWN:
+        default:
+                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 = -EBADF;
+        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;
+}
+
+SessionDevice *session_device_free(SessionDevice *sd) {
+        if (!sd)
+                return NULL;
+
+        /* 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);
+
+        return mfree(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;
+}