wlroots/backend/session/logind.c

696 lines
17 KiB
C

#define _POSIX_C_SOURCE 200809L
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/sysmacros.h>
#include <unistd.h>
#include <wayland-server-core.h>
#include <wlr/backend/session/interface.h>
#include <wlr/config.h>
#include <wlr/util/log.h>
#include "util/signal.h"
#if WLR_HAS_SYSTEMD
#include <systemd/sd-bus.h>
#include <systemd/sd-login.h>
#elif WLR_HAS_ELOGIND
#include <elogind/sd-bus.h>
#include <elogind/sd-login.h>
#endif
enum { DRM_MAJOR = 226 };
const struct session_impl session_logind;
struct logind_session {
struct wlr_session base;
sd_bus *bus;
struct wl_event_source *event;
char *id;
char *path;
// specifies whether a drm device was taken
// if so, the session will be (de)activated with the drm fd,
// otherwise with the dbus PropertiesChanged on "active" signal
bool has_drm;
};
static struct logind_session *logind_session_from_session(
struct wlr_session *base) {
assert(base->impl == &session_logind);
return (struct logind_session *)base;
}
static int logind_take_device(struct wlr_session *base, const char *path) {
struct logind_session *session = logind_session_from_session(base);
int fd = -1;
int ret;
sd_bus_message *msg = NULL;
sd_bus_error error = SD_BUS_ERROR_NULL;
struct stat st;
if (stat(path, &st) < 0) {
wlr_log(WLR_ERROR, "Failed to stat '%s'", path);
return -1;
}
if (major(st.st_rdev) == DRM_MAJOR) {
session->has_drm = true;
}
ret = sd_bus_call_method(session->bus, "org.freedesktop.login1",
session->path, "org.freedesktop.login1.Session", "TakeDevice",
&error, &msg, "uu", major(st.st_rdev), minor(st.st_rdev));
if (ret < 0) {
wlr_log(WLR_ERROR, "Failed to take device '%s': %s", path,
error.message);
goto out;
}
int paused = 0;
ret = sd_bus_message_read(msg, "hb", &fd, &paused);
if (ret < 0) {
wlr_log(WLR_ERROR, "Failed to parse D-Bus response for '%s': %s",
path, strerror(-ret));
goto out;
}
// The original fd seems to be closed when the message is freed
// so we just clone it.
fd = fcntl(fd, F_DUPFD_CLOEXEC, 0);
if (fd < 0) {
wlr_log(WLR_ERROR, "Failed to clone file descriptor for '%s': %s",
path, strerror(errno));
goto out;
}
out:
sd_bus_error_free(&error);
sd_bus_message_unref(msg);
return fd;
}
static void logind_release_device(struct wlr_session *base, int fd) {
struct logind_session *session = logind_session_from_session(base);
struct stat st;
if (fstat(fd, &st) < 0) {
wlr_log(WLR_ERROR, "Failed to stat device '%d': %s", fd,
strerror(errno));
return;
}
sd_bus_message *msg = NULL;
sd_bus_error error = SD_BUS_ERROR_NULL;
int ret = sd_bus_call_method(session->bus, "org.freedesktop.login1",
session->path, "org.freedesktop.login1.Session", "ReleaseDevice",
&error, &msg, "uu", major(st.st_rdev), minor(st.st_rdev));
if (ret < 0) {
wlr_log(WLR_ERROR, "Failed to release device '%d': %s", fd,
error.message);
}
sd_bus_error_free(&error);
sd_bus_message_unref(msg);
close(fd);
}
static bool logind_change_vt(struct wlr_session *base, unsigned vt) {
struct logind_session *session = logind_session_from_session(base);
// Only seat0 has VTs associated with it
if (strcmp(session->base.seat, "seat0") != 0) {
return true;
}
int ret;
sd_bus_message *msg = NULL;
sd_bus_error error = SD_BUS_ERROR_NULL;
ret = sd_bus_call_method(session->bus, "org.freedesktop.login1",
"/org/freedesktop/login1/seat/seat0", "org.freedesktop.login1.Seat", "SwitchTo",
&error, &msg, "u", (uint32_t)vt);
if (ret < 0) {
wlr_log(WLR_ERROR, "Failed to change to vt '%d'", vt);
}
sd_bus_error_free(&error);
sd_bus_message_unref(msg);
return ret >= 0;
}
static bool find_session_path(struct logind_session *session) {
int ret;
sd_bus_message *msg = NULL;
sd_bus_error error = SD_BUS_ERROR_NULL;
ret = sd_bus_call_method(session->bus, "org.freedesktop.login1",
"/org/freedesktop/login1", "org.freedesktop.login1.Manager",
"GetSession", &error, &msg, "s", session->id);
if (ret < 0) {
wlr_log(WLR_ERROR, "Failed to get session path: %s", error.message);
goto out;
}
const char *path;
ret = sd_bus_message_read(msg, "o", &path);
if (ret < 0) {
wlr_log(WLR_ERROR, "Could not parse session path: %s", error.message);
goto out;
}
session->path = strdup(path);
out:
sd_bus_error_free(&error);
sd_bus_message_unref(msg);
return ret >= 0;
}
static bool session_activate(struct logind_session *session) {
int ret;
sd_bus_message *msg = NULL;
sd_bus_error error = SD_BUS_ERROR_NULL;
ret = sd_bus_call_method(session->bus, "org.freedesktop.login1",
session->path, "org.freedesktop.login1.Session", "Activate",
&error, &msg, "");
if (ret < 0) {
wlr_log(WLR_ERROR, "Failed to activate session: %s", error.message);
}
sd_bus_error_free(&error);
sd_bus_message_unref(msg);
return ret >= 0;
}
static bool take_control(struct logind_session *session) {
int ret;
sd_bus_message *msg = NULL;
sd_bus_error error = SD_BUS_ERROR_NULL;
ret = sd_bus_call_method(session->bus, "org.freedesktop.login1",
session->path, "org.freedesktop.login1.Session", "TakeControl",
&error, &msg, "b", false);
if (ret < 0) {
wlr_log(WLR_ERROR, "Failed to take control of session: %s",
error.message);
}
sd_bus_error_free(&error);
sd_bus_message_unref(msg);
return ret >= 0;
}
static void release_control(struct logind_session *session) {
int ret;
sd_bus_message *msg = NULL;
sd_bus_error error = SD_BUS_ERROR_NULL;
ret = sd_bus_call_method(session->bus, "org.freedesktop.login1",
session->path, "org.freedesktop.login1.Session", "ReleaseControl",
&error, &msg, "");
if (ret < 0) {
wlr_log(WLR_ERROR, "Failed to release control of session: %s",
error.message);
}
sd_bus_error_free(&error);
sd_bus_message_unref(msg);
}
static void logind_session_destroy(struct wlr_session *base) {
struct logind_session *session = logind_session_from_session(base);
release_control(session);
wl_event_source_remove(session->event);
sd_bus_unref(session->bus);
free(session->id);
free(session->path);
free(session);
}
static int session_removed(sd_bus_message *msg, void *userdata,
sd_bus_error *ret_error) {
wlr_log(WLR_INFO, "SessionRemoved signal received");
return 0;
}
static struct wlr_device *find_device(struct wlr_session *session,
dev_t devnum) {
struct wlr_device *dev;
wl_list_for_each(dev, &session->devices, link) {
if (dev->dev == devnum) {
return dev;
}
}
wlr_log(WLR_ERROR, "Tried to use dev_t %lu not opened by session",
(unsigned long)devnum);
assert(0);
return NULL;
}
static int pause_device(sd_bus_message *msg, void *userdata,
sd_bus_error *ret_error) {
struct logind_session *session = userdata;
int ret;
uint32_t major, minor;
const char *type;
ret = sd_bus_message_read(msg, "uus", &major, &minor, &type);
if (ret < 0) {
wlr_log(WLR_ERROR, "Failed to parse D-Bus response for PauseDevice: %s",
strerror(-ret));
goto error;
}
if (major == DRM_MAJOR && strcmp(type, "gone") != 0) {
assert(session->has_drm);
session->base.active = false;
wlr_signal_emit_safe(&session->base.session_signal, session);
}
if (strcmp(type, "pause") == 0) {
ret = sd_bus_call_method(session->bus, "org.freedesktop.login1",
session->path, "org.freedesktop.login1.Session", "PauseDeviceComplete",
ret_error, &msg, "uu", major, minor);
if (ret < 0) {
wlr_log(WLR_ERROR, "Failed to send PauseDeviceComplete signal: %s",
strerror(-ret));
}
}
error:
return 0;
}
static int resume_device(sd_bus_message *msg, void *userdata,
sd_bus_error *ret_error) {
struct logind_session *session = userdata;
int ret;
int fd;
uint32_t major, minor;
ret = sd_bus_message_read(msg, "uuh", &major, &minor, &fd);
if (ret < 0) {
wlr_log(WLR_ERROR, "Failed to parse D-Bus response for ResumeDevice: %s",
strerror(-ret));
goto error;
}
if (major == DRM_MAJOR) {
struct wlr_device *dev = find_device(&session->base, makedev(major, minor));
close(dev->fd);
if (fcntl(fd, F_DUPFD_CLOEXEC, dev->fd) < 0) {
wlr_log_errno(WLR_ERROR, "Failed to duplicate file descriptor");
goto error;
}
if (!session->base.active) {
session->base.active = true;
wlr_signal_emit_safe(&session->base.session_signal, session);
}
}
error:
return 0;
}
static int properties_changed(sd_bus_message *msg, void *userdata,
sd_bus_error *ret_error) {
struct logind_session *session = userdata;
int ret = 0;
// if we have a drm fd we don't depend on this
if (session->has_drm) {
return 0;
}
// PropertiesChanged arg 1: interface
const char *interface;
ret = sd_bus_message_read_basic(msg, 's', &interface); // skip path
if (ret < 0) {
goto error;
}
if (strcmp(interface, "org.freedesktop.login1.Session") != 0) {
// not interesting for us; ignore
wlr_log(WLR_DEBUG, "ignoring PropertiesChanged from %s", interface);
return 0;
}
// PropertiesChanged arg 2: changed properties with values
ret = sd_bus_message_enter_container(msg, 'a', "{sv}");
if (ret < 0) {
goto error;
}
const char *s;
while ((ret = sd_bus_message_enter_container(msg, 'e', "sv")) > 0) {
ret = sd_bus_message_read_basic(msg, 's', &s);
if (ret < 0) {
goto error;
}
if (strcmp(s, "Active") == 0) {
int ret;
ret = sd_bus_message_enter_container(msg, 'v', "b");
if (ret < 0) {
goto error;
}
bool active;
ret = sd_bus_message_read_basic(msg, 'b', &active);
if (ret < 0) {
goto error;
}
if (session->base.active != active) {
session->base.active = active;
wlr_signal_emit_safe(&session->base.session_signal, session);
}
return 0;
} else {
sd_bus_message_skip(msg, "{sv}");
}
ret = sd_bus_message_exit_container(msg);
if (ret < 0) {
goto error;
}
}
if (ret < 0) {
goto error;
}
ret = sd_bus_message_exit_container(msg);
if (ret < 0) {
goto error;
}
// PropertiesChanged arg 3: changed properties without values
sd_bus_message_enter_container(msg, 'a', "s");
while ((ret = sd_bus_message_read_basic(msg, 's', &s)) > 0) {
if (strcmp(s, "Active") == 0) {
sd_bus_error error = SD_BUS_ERROR_NULL;
bool active;
ret = sd_bus_get_property_trivial(session->bus,
"org.freedesktop.login1", session->path,
"org.freedesktop.login1.Session", "Active", &error,
'b', &active);
if (ret < 0) {
wlr_log(WLR_ERROR, "Failed to get 'Active' property: %s",
error.message);
return 0;
}
if (session->base.active != active) {
session->base.active = active;
wlr_signal_emit_safe(&session->base.session_signal, session);
}
return 0;
}
}
if (ret < 0) {
goto error;
}
return 0;
error:
wlr_log(WLR_ERROR, "Failed to parse D-Bus PropertiesChanged: %s",
strerror(-ret));
return 0;
}
static bool add_signal_matches(struct logind_session *session) {
int ret;
char str[256];
const char fmt[] = "type='signal',"
"sender='org.freedesktop.login1',"
"interface='org.freedesktop.login1.%s',"
"member='%s',"
"path='%s'";
snprintf(str, sizeof(str), fmt, "Manager", "SessionRemoved",
"/org/freedesktop/login1");
ret = sd_bus_add_match(session->bus, NULL, str, session_removed, session);
if (ret < 0) {
wlr_log(WLR_ERROR, "Failed to add D-Bus match: %s", strerror(-ret));
return false;
}
snprintf(str, sizeof(str), fmt, "Session", "PauseDevice", session->path);
ret = sd_bus_add_match(session->bus, NULL, str, pause_device, session);
if (ret < 0) {
wlr_log(WLR_ERROR, "Failed to add D-Bus match: %s", strerror(-ret));
return false;
}
snprintf(str, sizeof(str), fmt, "Session", "ResumeDevice", session->path);
ret = sd_bus_add_match(session->bus, NULL, str, resume_device, session);
if (ret < 0) {
wlr_log(WLR_ERROR, "Failed to add D-Bus match: %s", strerror(-ret));
return false;
}
ret = sd_bus_match_signal(session->bus, NULL, "org.freedesktop.login1",
session->path, "org.freedesktop.DBus.Properties", "PropertiesChanged",
properties_changed, session);
if (ret < 0) {
wlr_log(WLR_ERROR, "Failed to add D-Bus match: %s", strerror(-ret));
return false;
}
return true;
}
static int dbus_event(int fd, uint32_t mask, void *data) {
sd_bus *bus = data;
while (sd_bus_process(bus, NULL) > 0) {
// Do nothing.
}
return 1;
}
static bool contains_str(const char *needle, const char **haystack) {
for (int i = 0; haystack[i]; i++) {
if (strcmp(haystack[i], needle) == 0) {
return true;
}
}
return false;
}
static bool get_greeter_session(char **session_id) {
char *class = NULL;
char **user_sessions = NULL;
int user_session_count = sd_uid_get_sessions(getuid(), 1, &user_sessions);
if (user_session_count < 0) {
wlr_log(WLR_ERROR, "Failed to get sessions");
goto out;
}
if (user_session_count == 0) {
wlr_log(WLR_ERROR, "User has no sessions");
goto out;
}
for (int i = 0; i < user_session_count; ++i) {
int ret = sd_session_get_class(user_sessions[i], &class);
if (ret < 0) {
continue;
}
if (strcmp(class, "greeter") == 0) {
*session_id = strdup(user_sessions[i]);
goto out;
}
}
out:
free(class);
for (int i = 0; i < user_session_count; ++i) {
free(user_sessions[i]);
}
free(user_sessions);
return *session_id != NULL;
}
static bool get_display_session(char **session_id) {
assert(session_id != NULL);
int ret;
char *type = NULL;
char *state = NULL;
char *xdg_session_id = getenv("XDG_SESSION_ID");
if (xdg_session_id) {
// This just checks whether the supplied session ID is valid
if (sd_session_is_active(xdg_session_id) < 0) {
wlr_log(WLR_ERROR, "Invalid XDG_SESSION_ID: '%s'", xdg_session_id);
goto error;
}
*session_id = strdup(xdg_session_id);
return true;
}
// If there's a session active for the current process then just use that
ret = sd_pid_get_session(getpid(), session_id);
if (ret == 0) {
return true;
}
// Find any active sessions for the user if the process isn't part of an
// active session itself
ret = sd_uid_get_display(getuid(), session_id);
if (ret < 0 && ret != -ENODATA) {
wlr_log(WLR_ERROR, "Failed to get display: %s", strerror(-ret));
goto error;
}
if (ret != 0 && !get_greeter_session(session_id)) {
wlr_log(WLR_ERROR, "Couldn't find an active session or a greeter session");
goto error;
}
assert(*session_id != NULL);
// Check that the available session is graphical
ret = sd_session_get_type(*session_id, &type);
if (ret < 0) {
wlr_log(WLR_ERROR, "Couldn't get a type for session '%s': %s",
*session_id, strerror(-ret));
goto error;
}
const char *graphical_session_types[] = {"wayland", "x11", "mir", NULL};
if (!contains_str(type, graphical_session_types)) {
wlr_log(WLR_ERROR, "Session '%s' isn't a graphical session (type: '%s')",
*session_id, type);
goto error;
}
// Check that the session is active
ret = sd_session_get_state(*session_id, &state);
if (ret < 0) {
wlr_log(WLR_ERROR, "Couldn't get state for session '%s': %s",
*session_id, strerror(-ret));
goto error;
}
const char *active_states[] = {"active", "online", NULL};
if (!contains_str(state, active_states)) {
wlr_log(WLR_ERROR, "Session '%s' is not active", *session_id);
goto error;
}
free(type);
free(state);
return true;
error:
free(type);
free(state);
free(*session_id);
*session_id = NULL;
return false;
}
static struct wlr_session *logind_session_create(struct wl_display *disp) {
int ret;
struct logind_session *session = calloc(1, sizeof(*session));
if (!session) {
wlr_log(WLR_ERROR, "Allocation failed: %s", strerror(errno));
return NULL;
}
if (!get_display_session(&session->id)) {
goto error;
}
char *seat;
ret = sd_session_get_seat(session->id, &seat);
if (ret < 0) {
wlr_log(WLR_ERROR, "Failed to get seat id: %s", strerror(-ret));
goto error;
}
snprintf(session->base.seat, sizeof(session->base.seat), "%s", seat);
if (strcmp(seat, "seat0") == 0) {
ret = sd_session_get_vt(session->id, &session->base.vtnr);
if (ret < 0) {
wlr_log(WLR_ERROR, "Session not running in virtual terminal");
goto error;
}
}
free(seat);
ret = sd_bus_default_system(&session->bus);
if (ret < 0) {
wlr_log(WLR_ERROR, "Failed to open D-Bus connection: %s", strerror(-ret));
goto error;
}
if (!find_session_path(session)) {
sd_bus_unref(session->bus);
goto error;
}
if (!add_signal_matches(session)) {
goto error_bus;
}
struct wl_event_loop *event_loop = wl_display_get_event_loop(disp);
session->event = wl_event_loop_add_fd(event_loop, sd_bus_get_fd(session->bus),
WL_EVENT_READABLE, dbus_event, session->bus);
if (!session_activate(session)) {
goto error_bus;
}
if (!take_control(session)) {
goto error_bus;
}
wlr_log(WLR_INFO, "Successfully loaded logind session");
session->base.impl = &session_logind;
return &session->base;
error_bus:
sd_bus_unref(session->bus);
free(session->path);
error:
free(session->id);
return NULL;
}
const struct session_impl session_logind = {
.create = logind_session_create,
.destroy = logind_session_destroy,
.open = logind_take_device,
.close = logind_release_device,
.change_vt = logind_change_vt,
};