From ff5349960f1cf7af5404b0f765c57eb386c91216 Mon Sep 17 00:00:00 2001

From: Lennart Poettering <lennart@poettering.net>

Date: Fri, 13 Nov 2015 18:25:02 +0100

Subject: [PATCH] logind: add a new UserTasksMax= setting to logind.conf

This new setting configures the TasksMax= field for the slice objects we

create for each user.

This alters logind to create the slice unit as transient unit explicitly

instead of relying on implicit generation of slice units by simply

starting them. This also enables us to set a friendly description for

slice units that way.

Cherry-picked from: 90558f315844ec35e3fd4f1a19ac38c8721c9354

Conflicts:

	src/login/logind-dbus.c

	src/login/logind-user.c

	src/login/logind.conf

	src/login/logind.h

Resolves: #1337244

---

 man/logind.conf.xml          | 15 +++++-

 src/login/logind-dbus.c      | 94 +++++++++++++++++++++++++++++++++++-

 src/login/logind-gperf.gperf |  1 +

 src/login/logind-session.c   | 25 ++++++----

 src/login/logind-session.h   |  3 +-

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

 src/login/logind.c           |  1 +

 src/login/logind.conf        |  1 +

 src/login/logind.h           |  4 +-

 9 files changed, 160 insertions(+), 25 deletions(-)

diff --git a/man/logind.conf.xml b/man/logind.conf.xml

index 54651f07d..bcc8ee975 100644

--- a/man/logind.conf.xml

+++ b/man/logind.conf.xml

@@ -1,4 +1,4 @@

- 

+ 

   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">

@@ -262,7 +262,18 @@

         limit relative to the amount of physical RAM. Defaults to 10%.

         Note that this size is a safety limit only. As each runtime

         directory is a tmpfs file system, it will only consume as much

-        memory as is needed. </para></listitem>

+        memory as is needed.</para></listitem>

+      </varlistentry>

+

+      <varlistentry>

+        <term><varname>UserTasksMax=</varname></term>

+

+        <listitem><para>Sets the maximum number of OS tasks each user

+        may run concurrently. This controls the

+        <varname>TasksMax=</varname> setting of the per-user slice

+        unit, see

+        <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>

+        for details.</para></listitem>

       </varlistentry>

       <varlistentry>

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

index fb84e92e5..63b9a0df3 100644

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

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

@@ -2325,13 +2325,101 @@ int manager_dispatch_delayed(Manager *manager) {

         return 1;

 }

+int manager_start_slice(

+                Manager *manager,

+                const char *slice,

+                const char *description,

+                const char *after,

+                const char *after2,

+                uint64_t tasks_max,

+                sd_bus_error *error,

+                char **job) {

+

+        _cleanup_bus_message_unref_ sd_bus_message *m = NULL, *reply = NULL;

+        int r;

+

+        assert(manager);

+        assert(slice);

+

+        r = sd_bus_message_new_method_call(

+                        manager->bus,

+                        &m,

+                        "org.freedesktop.systemd1",

+                        "/org/freedesktop/systemd1",

+                        "org.freedesktop.systemd1.Manager",

+                        "StartTransientUnit");

+        if (r < 0)

+                return r;

+

+        r = sd_bus_message_append(m, "ss", strempty(slice), "fail");

+        if (r < 0)

+                return r;

+

+        r = sd_bus_message_open_container(m, 'a', "(sv)");

+        if (r < 0)

+                return r;

+

+        if (!isempty(description)) {

+                r = sd_bus_message_append(m, "(sv)", "Description", "s", description);

+                if (r < 0)

+                        return r;

+        }

+

+        if (!isempty(after)) {

+                r = sd_bus_message_append(m, "(sv)", "After", "as", 1, after);

+                if (r < 0)

+                        return r;

+        }

+

+        if (!isempty(after2)) {

+                r = sd_bus_message_append(m, "(sv)", "After", "as", 1, after2);

+                if (r < 0)

+                        return r;

+        }

+

+        r = sd_bus_message_append(m, "(sv)", "TasksMax", "t", tasks_max);

+        if (r < 0)

+                return r;

+

+        r = sd_bus_message_close_container(m);

+        if (r < 0)

+                return r;

+

+        r = sd_bus_message_append(m, "a(sa(sv))", 0);

+        if (r < 0)

+                return r;

+

+        r = sd_bus_call(manager->bus, m, 0, error, &reply);

+        if (r < 0)

+                return r;

+

+        if (job) {

+                const char *j;

+                char *copy;

+

+                r = sd_bus_message_read(reply, "o", &j);

+                if (r < 0)

+                        return r;

+

+                copy = strdup(j);

+                if (!copy)

+                        return -ENOMEM;

+

+                *job = copy;

+        }

+

+        return 1;

+}

+

 int manager_start_scope(

                 Manager *manager,

                 const char *scope,

                 pid_t pid,

                 const char *slice,

                 const char *description,

-                const char *after, const char *after2,

+                const char *after,

+                const char *after2,

+                uint64_t tasks_max,

                 sd_bus_error *error,

                 char **job) {

@@ -2399,6 +2487,10 @@ int manager_start_scope(

         if (r < 0)

                 return r;

+        r = sd_bus_message_append(m, "(sv)", "TasksMax", "t", tasks_max);

+        if (r < 0)

+                return r;

+

         r = sd_bus_message_close_container(m);

         if (r < 0)

                 return r;

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

index 62460673b..8a064e2a9 100644

--- a/src/login/logind-gperf.gperf

+++ b/src/login/logind-gperf.gperf

@@ -33,3 +33,4 @@ Login.IdleAction,                  config_parse_handle_action, 0, offsetof(Manag

 Login.IdleActionSec,               config_parse_sec,           0, offsetof(Manager, idle_action_usec)

 Login.RuntimeDirectorySize,        config_parse_tmpfs_size,    0, offsetof(Manager, runtime_dir_size)

 Login.RemoveIPC,                   config_parse_bool,          0, offsetof(Manager, remove_ipc)

+Login.UserTasksMax,                config_parse_uint64,        0, offsetof(Manager, user_tasks_max)

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

index 746e50aa5..4575a029f 100644

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

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

@@ -510,21 +510,28 @@ static int session_start_scope(Session *s) {

         if (!s->scope) {

                 _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;

-                _cleanup_free_ char *description = NULL;

                 char *scope, *job = NULL;

-

-                description = strjoin("Session ", s->id, " of user ", s->user->name, NULL);

-                if (!description)

-                        return log_oom();

+                const char *description;

                 scope = strjoin("session-", s->id, ".scope", NULL);

                 if (!scope)

                         return log_oom();

-                r = manager_start_scope(s->manager, scope, s->leader, s->user->slice, description, "systemd-logind.service", "systemd-user-sessions.service", &error, &job;;

+                description = strjoina("Session ", s->id, " of user ", s->user->name, NULL);

+

+                r = manager_start_scope(

+                                s->manager,

+                                scope,

+                                s->leader,

+                                s->user->slice,

+                                description,

+                                "systemd-logind.service",

+                                "systemd-user-sessions.service",

+                                (uint64_t) -1, /* disable TasksMax= for the scope, rely on the slice setting for it */

+                                &error,

+                                &job;;

                 if (r < 0) {

-                        log_error("Failed to start session scope %s: %s %s",

-                                  scope, bus_error_message(&error, r), error.name);

+                        log_error_errno(r, "Failed to start session scope %s: %s", scope, bus_error_message(&error, r));

                         free(scope);

                         return r;

                 } else {

@@ -536,7 +543,7 @@ static int session_start_scope(Session *s) {

         }

         if (s->scope)

-                hashmap_put(s->manager->session_units, s->scope, s);

+                (void) hashmap_put(s->manager->session_units, s->scope, s);

         return 0;

 }

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

index 5002b6868..d662082d8 100644

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

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

@@ -115,7 +115,8 @@ struct Session {

         bool in_gc_queue:1;

         bool started:1;

-        bool stopping:1;

+

+        bool stopping;

         sd_bus_message *create_message;

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

index 97eb4feca..4298704ce 100644

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

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

@@ -33,6 +33,7 @@

 #include "special.h"

 #include "unit-name.h"

 #include "bus-util.h"

+#include "bus-common-errors.h"

 #include "bus-error.h"

 #include "conf-parser.h"

 #include "clean-ipc.h"

@@ -367,34 +368,52 @@ fail:

 }

 static int user_start_slice(User *u) {

-        char *job;

         int r;

         assert(u);

         if (!u->slice) {

                 _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;

-                char lu[DECIMAL_STR_MAX(uid_t) + 1], *slice;

-                sprintf(lu, UID_FMT, u->uid);

+                char lu[DECIMAL_STR_MAX(uid_t) + 1], *slice, *job;

+                const char *description;

+

+                free(u->slice_job);

+                u->slice_job = NULL;

+                xsprintf(lu, UID_FMT, u->uid);

                 r = build_subslice(SPECIAL_USER_SLICE, lu, &slice);

                 if (r < 0)

-                        return r;

-

-                r = manager_start_unit(u->manager, slice, &error, &job;;

+                        return log_error_errno(r, "Failed to build slice name: %m");

+

+                description = strjoina("User Slice of ", u->name);

+

+                r = manager_start_slice(

+                                u->manager,

+                                slice,

+                                description,

+                                "systemd-logind.service",

+                                "systemd-user-sessions.service",

+                                u->manager->user_tasks_max,

+                                &error,

+                                &job;;

                 if (r < 0) {

-                        log_error("Failed to start user slice: %s", bus_error_message(&error, r));

-                        free(slice);

+

+                        if (sd_bus_error_has_name(&error, BUS_ERROR_UNIT_EXISTS))

+                                /* The slice already exists? If so, that's fine, let's just reuse it */

+                                u->slice = slice;

+                        else {

+                                log_error_errno(r, "Failed to start user slice %s, ignoring: %s (%s)", slice, bus_error_message(&error, r), error.name);

+                                free(slice);

+                                /* we don't fail due to this, let's try to continue */

+                        }

                 } else {

                         u->slice = slice;

-

-                        free(u->slice_job);

                         u->slice_job = job;

                 }

         }

         if (u->slice)

-                hashmap_put(u->manager->user_units, u->slice, u);

+                (void) hashmap_put(u->manager->user_units, u->slice, u);

         return 0;

 }

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

index e8d0669bb..16c931c3e 100644

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

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

@@ -63,6 +63,7 @@ Manager *manager_new(void) {

         m->idle_action_not_before_usec = now(CLOCK_MONOTONIC);

         m->runtime_dir_size = PAGE_ALIGN((size_t) (physical_memory() / 10)); /* 10% */

+        m->user_tasks_max = (uint64_t) -1;

         m->devices = hashmap_new(&string_hash_ops);

         m->seats = hashmap_new(&string_hash_ops);

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

index be8d7dff2..d33e0b34d 100644

--- a/src/login/logind.conf

+++ b/src/login/logind.conf

@@ -31,3 +31,4 @@

 #IdleActionSec=30min

 #RuntimeDirectorySize=10%

 #RemoveIPC=no

+#UserTasksMax=

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

index e0cb7d023..8503eb24d 100644

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

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

@@ -128,6 +128,7 @@ struct Manager {

         sd_event_source *lid_switch_ignore_event_source;

         size_t runtime_dir_size;

+        uint64_t user_tasks_max;

 };

 Manager *manager_new(void);

@@ -176,7 +177,8 @@ int manager_send_changed(Manager *manager, const char *property, ...) _sentinel_

 int manager_dispatch_delayed(Manager *manager);

-int manager_start_scope(Manager *manager, const char *scope, pid_t pid, const char *slice, const char *description, const char *after, const char *after2, sd_bus_error *error, char **job);

+int manager_start_slice(Manager *manager, const char *slice, const char *description, const char *after, const char *after2, uint64_t tasks_max, sd_bus_error *error, char **job);

+int manager_start_scope(Manager *manager, const char *scope, pid_t pid, const char *slice, const char *description, const char *after, const char *after2, uint64_t tasks_max, sd_bus_error *error, char **job);

 int manager_start_unit(Manager *manager, const char *unit, sd_bus_error *error, char **job);

 int manager_stop_unit(Manager *manager, const char *unit, sd_bus_error *error, char **job);

 int manager_abandon_scope(Manager *manager, const char *scope, sd_bus_error *error);