From fbc394252588325b6e7ecd1ab65ad40b51763c58 Mon Sep 17 00:00:00 2001

From: Lennart Poettering <lennart@poettering.net>

Date: Tue, 7 Aug 2018 12:08:24 +0200

Subject: [PATCH] logind: add hashtable for finding session by leader PID

This is useful later on, when we quickly want to find the session for a

leader PID.

(cherry picked from commit 238794b15082e6f61d0ce2943d39205289fff7f0)

Related: #2122288

---

 src/login/logind-core.c    | 15 ++++++++------

 src/login/logind-dbus.c    |  3 +--

 src/login/logind-session.c | 41 +++++++++++++++++++++++++++++++++++---

 src/login/logind-session.h |  1 +

 src/login/logind.c         |  4 +++-

 src/login/logind.h         |  1 +

 6 files changed, 53 insertions(+), 12 deletions(-)

diff --git a/src/login/logind-core.c b/src/login/logind-core.c

index 7e33f8e6aa..a1943b6f9d 100644

--- a/src/login/logind-core.c

+++ b/src/login/logind-core.c

@@ -339,13 +339,16 @@ int manager_get_session_by_pid(Manager *m, pid_t pid, Session **ret) {

         if (!pid_is_valid(pid))

                 return -EINVAL;

-        r = cg_pid_get_unit(pid, &unit);

-        if (r < 0)

-                goto not_found;

+        s = hashmap_get(m->sessions_by_leader, PID_TO_PTR(pid));

+        if (!s) {

+                r = cg_pid_get_unit(pid, &unit);

+                if (r < 0)

+                        goto not_found;

-        s = hashmap_get(m->session_units, unit);

-        if (!s)

-                goto not_found;

+                s = hashmap_get(m->session_units, unit);

+                if (!s)

+                        goto not_found;

+        }

         if (ret)

                 *ret = s;

diff --git a/src/login/logind-dbus.c b/src/login/logind-dbus.c

index 0248042308..01bfef4ff7 100644

--- a/src/login/logind-dbus.c

+++ b/src/login/logind-dbus.c

@@ -784,9 +784,8 @@ static int method_create_session(sd_bus_message *message, void *userdata, sd_bus

                 goto fail;

         session_set_user(session, user);

+        session_set_leader(session, leader);

-        session->leader = leader;

-        session->audit_id = audit_id;

         session->type = t;

         session->class = c;

         session->remote = remote;

diff --git a/src/login/logind-session.c b/src/login/logind-session.c

index d666f86d3f..cc838ca383 100644

--- a/src/login/logind-session.c

+++ b/src/login/logind-session.c

@@ -121,6 +121,9 @@ Session* session_free(Session *s) {

                 free(s->scope);

         }

+        if (pid_is_valid(s->leader))

+                (void) hashmap_remove_value(s->manager->sessions_by_leader, PID_TO_PTR(s->leader), s);

+

         free(s->scope_job);

         sd_bus_message_unref(s->create_message);

@@ -149,6 +152,30 @@ void session_set_user(Session *s, User *u) {

         user_update_last_session_timer(u);

 }

+int session_set_leader(Session *s, pid_t pid) {

+        int r;

+

+        assert(s);

+

+        if (!pid_is_valid(pid))

+                return -EINVAL;

+

+        if (s->leader == pid)

+                return 0;

+

+        r = hashmap_put(s->manager->sessions_by_leader, PID_TO_PTR(pid), s);

+        if (r < 0)

+                return r;

+

+        if (pid_is_valid(s->leader))

+                (void) hashmap_remove_value(s->manager->sessions_by_leader, PID_TO_PTR(s->leader), s);

+

+        s->leader = pid;

+        (void) audit_session_from_pid(pid, &s->audit_id);

+

+        return 1;

+}

+

 static void session_save_devices(Session *s, FILE *f) {

         SessionDevice *sd;

         Iterator i;

@@ -473,8 +500,16 @@ int session_load(Session *s) {

         }

         if (leader) {

-                if (parse_pid(leader, &s->leader) >= 0)

-                        (void) audit_session_from_pid(s->leader, &s->audit_id);

+                pid_t pid;

+

+                r = parse_pid(leader, &pid;;

+                if (r < 0)

+                        log_debug_errno(r, "Failed to parse leader PID of session: %s", leader);

+                else {

+                        r = session_set_leader(s, pid);

+                        if (r < 0)

+                                log_warning_errno(r, "Failed to set session leader PID, ignoring: %m");

+                }

         }

         if (type) {

@@ -910,7 +945,7 @@ int session_get_idle_hint(Session *s, dual_timestamp *t) {

         /* For sessions with a leader but no explicitly configured

          * tty, let's check the controlling tty of the leader */

-        if (s->leader > 0) {

+        if (pid_is_valid(s->leader)) {

                 r = get_process_ctty_atime(s->leader, &atime);

                 if (r >= 0)

                         goto found_atime;

diff --git a/src/login/logind-session.h b/src/login/logind-session.h

index 7da845cea3..8c7d0301f2 100644

--- a/src/login/logind-session.h

+++ b/src/login/logind-session.h

@@ -124,6 +124,7 @@ Session* session_free(Session *s);

 DEFINE_TRIVIAL_CLEANUP_FUNC(Session *, session_free);

 void session_set_user(Session *s, User *u);

+int session_set_leader(Session *s, pid_t pid);

 bool session_may_gc(Session *s, bool drop_not_started);

 void session_add_to_gc_queue(Session *s);

 int session_activate(Session *s);

diff --git a/src/login/logind.c b/src/login/logind.c

index 25de9a6ab2..6b576dad0d 100644

--- a/src/login/logind.c

+++ b/src/login/logind.c

@@ -46,6 +46,7 @@ static int manager_new(Manager **ret) {

         m->devices = hashmap_new(&string_hash_ops);

         m->seats = hashmap_new(&string_hash_ops);

         m->sessions = hashmap_new(&string_hash_ops);

+        m->sessions_by_leader = hashmap_new(NULL);

         m->users = hashmap_new(NULL);

         m->inhibitors = hashmap_new(&string_hash_ops);

         m->buttons = hashmap_new(&string_hash_ops);

@@ -53,7 +54,7 @@ static int manager_new(Manager **ret) {

         m->user_units = hashmap_new(&string_hash_ops);

         m->session_units = hashmap_new(&string_hash_ops);

-        if (!m->devices || !m->seats || !m->sessions || !m->users || !m->inhibitors || !m->buttons || !m->user_units || !m->session_units)

+        if (!m->devices || !m->seats || !m->sessions || !m->sessions_by_leader || !m->users || !m->inhibitors || !m->buttons || !m->user_units || !m->session_units)

                 return -ENOMEM;

         m->udev = udev_new();

@@ -112,6 +113,7 @@ static Manager* manager_unref(Manager *m) {

         hashmap_free(m->devices);

         hashmap_free(m->seats);

         hashmap_free(m->sessions);

+        hashmap_free(m->sessions_by_leader);

         hashmap_free(m->users);

         hashmap_free(m->inhibitors);

         hashmap_free(m->buttons);

diff --git a/src/login/logind.h b/src/login/logind.h

index bb127bf4a5..7f94dea2f6 100644

--- a/src/login/logind.h

+++ b/src/login/logind.h

@@ -26,6 +26,7 @@ struct Manager {

         Hashmap *devices;

         Hashmap *seats;

         Hashmap *sessions;

+        Hashmap *sessions_by_leader;

         Hashmap *users;

         Hashmap *inhibitors;

         Hashmap *buttons;