On Thu, 06.02.14 21:37, Djalal Harouni (tix...@opendz.org) wrote: I think this one I fixed by adding a new "stopping" variable. Could you check?
> Currently the user and session states are not stable, they are affected > by several races during login: > > 1) session state: > To get the session state the function session_get_state() is used. > > Opening state: > At login the D-Bus CreateSession() method will call session_start() which > calls user_start() and session_start_scope() to queue the scope job and > set the session->scope_job > > => session_get_state() == SESSION_OPENING (correct) > > Then execution will continue from session_send_create() which is called > by the D-Bus match_job_removed() signal. math_job_removed() will check if > this is the session scope and if this is the previously queued scope job. > If so it will clear the session->scope_job > > => session_get_state() == SESSION_CLOSING (incorrect) > (session closing since fifo_fd == -1) > > So scope job has finished and scope was created successfully, later the > session_send_create_reply() will wait for the session scope *and* the > user service to be successfully created. > > /* user service is still pending */ > if (s->scope_job || s->user->service_job)) > return 0 > > => session_get_state() == SESSION_CLOSING (incorrect) > > else > session_create_fifo() /* fifo_fd finally created */ > > => session_get_state() == SESSION_ACTIVE (correct) > > To sum it up, current state during login: > "SESSION_OPENING"=>"SESSION_CLOSING"x2=>"SESSION_ACTIVE" > > To fix the session state and remove the two incorrect SESSION_CLOSING, > we do not clear up the "session->scope_job" when we detect that this is > the session scope, we setup a temporary variable "scope_job" that will > get the current value of "session->scope_job" and update it if > necessary. > > Add a new "active" variable to check if the session scope and user > service jobs are still being created. > > Update session_jobs_replay() and session_send_create_reply() function to > receive the "opening" variable as an argument, so it will still wait for > the scope and service jobs to finish before creating the session fifo. > > The "session->scope_job" will be cleared when session_jobs_reply() > finishes. This ensures that the state will just go from: > "SESSION_OPENING" => "SESSION_ACTIVE" > > 2) user state: > To get the user state the function user_get_state() is used. > > I'll add that the user_get_state() and session_get_state() do not have > the same logic when it comes to sessions, this will just add ambiguity. > user_get_state() calls session_is_active() before checking > session_get_state(), and session_is_active() will return true right from > the start since the logic is set during D-Bus CreateSession(). This will > we be fixed in the followup patches. > > Opening state: > At login we have session_start() which calls user_start() > > here we already: > > => user_get_state() == USER_ACTIVE (incorrect) > (not fixed in this patch) > > user_start() calls: > user_start_slice() queue the slice and set user->slice_job > user_start_service() queue the service and set user->service_job > > => user_get_state() == USER_OPENING (correct) > > Then execution will continue from session_send_create() which is called > by the D-Bus match_job_removed() signal. math_job_removed() will check if > these are the user service and slice and if they are the previously queued > jobs. If so it will clear the: user->service_job and user->slice_job > > => user_get_state() == USER_ACTIVE (incorrect) > (incorrect since the fifo_fd has not been created, > here the state should stay USER_OPENING) > > Later when the user service is created successfully, > session_send_create_reply() will also wait for the session scope to be > created. If so then session_send_create_reply() will continue and call > session_create_fifo() > > => user_get_state() == USER_ACTIVE (correct) > (fifo_fd was created) > > To fix this, we use the same logic as used to fix session states. In > order to remove the incorrect state when the fifo_fd is not created but > the state shows USER_ACTIVE, we do not clear the "user->service_job" and > "user->slice_job" right away, we store the state in a temporary variable > "service_job" and update it later if we detect that this is the user > service. > > The new "active" variable will be used to check if the session scope and > user service are still being created. If so we'll wait for the next > match_job_removed() signal and continue, otherwise we proceed with > session_jobs_reply() and session_send_create_reply() in order to notify > clients. > --- > src/login/logind-dbus.c | 44 > ++++++++++++++++++++++++++++++----------- > src/login/logind-session-dbus.c | 8 +++++--- > src/login/logind-session.h | 2 +- > 3 files changed, 39 insertions(+), 15 deletions(-) > > diff --git a/src/login/logind-dbus.c b/src/login/logind-dbus.c > index 7b050fb..0560707 100644 > --- a/src/login/logind-dbus.c > +++ b/src/login/logind-dbus.c > @@ -1919,7 +1919,9 @@ const sd_bus_vtable manager_vtable[] = { > SD_BUS_VTABLE_END > }; > > -static int session_jobs_reply(Session *s, const char *unit, const char > *result) { > +/* session_jobs_reply() calls session_send_create_reply() to > + * notify client that they are able to login now. */ > +static int session_jobs_reply(Session *s, const char *unit, const char > *result, bool opening) { > int r = 0; > > assert(s); > @@ -1929,12 +1931,12 @@ static int session_jobs_reply(Session *s, const char > *unit, const char *result) > return r; > > if (streq(result, "done")) > - r = session_send_create_reply(s, NULL); > + r = session_send_create_reply(s, NULL, opening); > else { > _cleanup_bus_error_free_ sd_bus_error e = SD_BUS_ERROR_NULL; > > sd_bus_error_setf(&e, BUS_ERROR_JOB_FAILED, "Start job for > unit %s failed with '%s'", unit, result); > - r = session_send_create_reply(s, &e); > + r = session_send_create_reply(s, &e, opening); > } > > return r; > @@ -1973,22 +1975,46 @@ int match_job_removed(sd_bus *bus, sd_bus_message > *message, void *userdata, sd_b > > session = hashmap_get(m->session_units, unit); > if (session) { > + bool active, scope_job = !!session->scope_job; > > - if (streq_ptr(path, session->scope_job)) { > + /* Set to false if the scope job has finished */ > + if (streq_ptr(path, session->scope_job)) > + scope_job = false; > + > + /* If the session scope and the user service are still > + * being created this will be set to true, otherwise > + * it will be false */ > + active = scope_job || !!session->user->service_job; > + session_jobs_reply(session, unit, result, active); > + > + if (!scope_job) { > + /* Clean this up after session_jobs_reply() */ > free(session->scope_job); > session->scope_job = NULL; > } > > - session_jobs_reply(session, unit, result); > - > session_save(session); > session_add_to_gc_queue(session); > } > > user = hashmap_get(m->user_units, unit); > if (user) { > + bool active, service_job = !!user->service_job; > + > + /* Set to false if the user service has finished */ > + if (streq_ptr(path, user->service_job)) > + service_job = false; > + > + LIST_FOREACH(sessions_by_user, session, user->sessions) { > + /* If the session scope and the user service are > + * still being created this will be set to true, > + * otherwise it will be false */ > + active = service_job || !!session->scope_job; > + session_jobs_reply(session, unit, result, active); > + } > > - if (streq_ptr(path, user->service_job)) { > + if (!service_job) { > + /* Clean this up after session_jobs_reply() */ > free(user->service_job); > user->service_job = NULL; > } > @@ -1998,10 +2024,6 @@ int match_job_removed(sd_bus *bus, sd_bus_message > *message, void *userdata, sd_b > user->slice_job = NULL; > } > > - LIST_FOREACH(sessions_by_user, session, user->sessions) { > - session_jobs_reply(session, unit, result); > - } > - > user_save(user); > user_add_to_gc_queue(user); > } > diff --git a/src/login/logind-session-dbus.c b/src/login/logind-session-dbus.c > index 7ee4956..54db864 100644 > --- a/src/login/logind-session-dbus.c > +++ b/src/login/logind-session-dbus.c > @@ -641,7 +641,7 @@ int session_send_lock_all(Manager *m, bool lock) { > return r; > } > > -int session_send_create_reply(Session *s, sd_bus_error *error) { > +int session_send_create_reply(Session *s, sd_bus_error *error, bool opening) > { > _cleanup_bus_message_unref_ sd_bus_message *c = NULL; > _cleanup_close_ int fifo_fd = -1; > _cleanup_free_ char *p = NULL; > @@ -650,12 +650,12 @@ int session_send_create_reply(Session *s, sd_bus_error > *error) { > > /* This is called after the session scope and the user service > * were successfully created, and finishes where > - * bus_manager_create_session() left off. */ > + * method_create_session() left off. */ > > if (!s->create_message) > return 0; > > - if (!sd_bus_error_is_set(error) && (s->scope_job || > s->user->service_job)) > + if (!sd_bus_error_is_set(error) && opening) > return 0; > > c = s->create_message; > @@ -664,6 +664,8 @@ int session_send_create_reply(Session *s, sd_bus_error > *error) { > if (error) > return sd_bus_reply_method_error(c, error); > > + /* At this stage the session scope and the user service > + * were successfully created */ > fifo_fd = session_create_fifo(s); > if (fifo_fd < 0) > return fifo_fd; > diff --git a/src/login/logind-session.h b/src/login/logind-session.h > index 7bf1932..ebe3902 100644 > --- a/src/login/logind-session.h > +++ b/src/login/logind-session.h > @@ -152,7 +152,7 @@ int session_send_changed(Session *s, const char > *properties, ...) _sentinel_; > int session_send_lock(Session *s, bool lock); > int session_send_lock_all(Manager *m, bool lock); > > -int session_send_create_reply(Session *s, sd_bus_error *error); > +int session_send_create_reply(Session *s, sd_bus_error *error, bool opening); > > const char* session_state_to_string(SessionState t) _const_; > SessionState session_state_from_string(const char *s) _pure_; Lennart -- Lennart Poettering, Red Hat _______________________________________________ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel