From 1c961f8bf67a798d51d88195f89d035012a681d4 Mon Sep 17 00:00:00 2001

From: Michal Sekletar <msekleta@redhat.com>

Date: Thu, 27 Feb 2014 17:56:16 +0100

Subject: [PATCH] core: introduce new stop protocol for unit scopes

By specifiy a Controller property when creating the scope a client can

specify a bus name that will be notified with a RequestStop bus signal

when the scope has been asked to shut down, instead of sending SIGTERM

to the scope processes themselves.

https://bugzilla.redhat.com/show_bug.cgi?id=1032695

Based-on: 2d4a39e759c4ab846ad8a546abeddd40bc8d736e

---

 src/core/dbus-scope.c    | 55 ++++++++++++++++++++++++++++++++++++++++++++++++

 src/core/dbus-scope.h    |  2 ++

 src/core/scope.c         | 20 +++++++++++++++---

 src/core/scope.h         |  2 ++

 src/run/run.c            |  8 +++++++

 src/shared/dbus-common.c | 42 ++++++++++++++++++++++++++++++++++++

 src/shared/dbus-common.h |  2 ++

 7 files changed, 128 insertions(+), 3 deletions(-)

diff --git a/src/core/dbus-scope.c b/src/core/dbus-scope.c

index 783a969..b576f76 100644

--- a/src/core/dbus-scope.c

+++ b/src/core/dbus-scope.c

@@ -31,10 +31,12 @@

 #define BUS_SCOPE_INTERFACE                                             \

         " <interface name=\"org.freedesktop.systemd1.Scope\">\n"        \

         BUS_UNIT_CGROUP_INTERFACE                                       \

+        "  <property name=\"Controller\" type=\"s\" access=\"read\"/>\n"\

         "  <property name=\"TimeoutStopUSec\" type=\"t\" access=\"read\"/>\n" \

         BUS_KILL_CONTEXT_INTERFACE                                      \

         BUS_CGROUP_CONTEXT_INTERFACE                                    \

         "  <property name=\"Result\" type=\"s\" access=\"read\"/>\n"    \

+        "  <signal name=\"RequestStop\"/>\n"                            \

         " </interface>\n"

 #define INTROSPECTION                                                   \

@@ -56,6 +58,7 @@ const char bus_scope_interface[] _introspect_("Scope") = BUS_SCOPE_INTERFACE;

 static DEFINE_BUS_PROPERTY_APPEND_ENUM(bus_scope_append_scope_result, scope_result, ScopeResult);

 static const BusProperty bus_scope_properties[] = {

+        { "Controller",             bus_property_append_string,    "s", offsetof(Scope, controller)        },

         { "TimeoutStopUSec",        bus_property_append_usec,      "t", offsetof(Scope, timeout_stop_usec) },

         { "Result",                 bus_scope_append_scope_result, "s", offsetof(Scope, result)            },

         {}

@@ -127,6 +130,31 @@ static int bus_scope_set_transient_property(

                 return 1;

+        } else if (streq(name, "Controller")) {

+                const char *controller;

+

+                if (dbus_message_iter_get_arg_type(i) != DBUS_TYPE_STRING)

+                        return -EINVAL;

+

+                dbus_message_iter_get_basic(i, &controller);

+

+                if (!isempty(controller) && !bus_service_name_is_valid(controller))

+                        return -EINVAL;

+

+                if (mode != UNIT_CHECK) {

+                        char *c = NULL;

+

+                        if (!isempty(controller)) {

+                                c = strdup(controller);

+                                if (!c)

+                                        return -ENOMEM;

+                        }

+

+                        free(s->controller);

+                        s->controller = c;

+                }

+

+                return 1;

         } else if (streq(name, "TimeoutStopUSec")) {

                 if (dbus_message_iter_get_arg_type(i) != DBUS_TYPE_UINT64)

@@ -187,3 +215,30 @@ int bus_scope_commit_properties(Unit *u) {

         unit_realize_cgroup(u);

         return 0;

 }

+

+int bus_scope_send_request_stop(Scope *s) {

+        _cleanup_dbus_message_unref_ DBusMessage *m = NULL;

+        _cleanup_free_ char *p = NULL;

+        int r;

+

+        assert(s);

+

+        if (!s->controller)

+                return 0;

+

+        p = unit_dbus_path(UNIT(s));

+        if (!p)

+                return -ENOMEM;

+

+        m = dbus_message_new_signal(p,

+                                    "org.freedesktop.systemd1.Scope",

+                                    "RequestStop");

+        if (!m)

+                return 0;

+

+        r = dbus_message_set_destination(m, s->controller);

+        if (!r)

+                return 0;

+

+        return dbus_connection_send(UNIT(s)->manager->api_bus, m, NULL);

+}

diff --git a/src/core/dbus-scope.h b/src/core/dbus-scope.h

index e6836f1..34720f2 100644

--- a/src/core/dbus-scope.h

+++ b/src/core/dbus-scope.h

@@ -30,4 +30,6 @@ DBusHandlerResult bus_scope_message_handler(Unit *u, DBusConnection *c, DBusMess

 int bus_scope_set_property(Unit *u, const char *name, DBusMessageIter *i, UnitSetPropertiesMode mode, DBusError *error);

 int bus_scope_commit_properties(Unit *u);

+int bus_scope_send_request_stop(Scope *s);

+

 extern const char bus_scope_interface[];

diff --git a/src/core/scope.c b/src/core/scope.c

index 41da3b9..e75fc2b 100644

--- a/src/core/scope.c

+++ b/src/core/scope.c

@@ -64,6 +64,9 @@ static void scope_done(Unit *u) {

         cgroup_context_done(&s->cgroup_context);

+        free(s->controller);

+        s->controller = NULL;

+

         set_free(s->pids);

         s->pids = NULL;

@@ -198,6 +201,7 @@ static void scope_enter_dead(Scope *s, ScopeResult f) {

 }

 static void scope_enter_signal(Scope *s, ScopeState state, ScopeResult f) {

+        bool skip_signal = false;

         int r;

         assert(s);

@@ -205,13 +209,23 @@ static void scope_enter_signal(Scope *s, ScopeState state, ScopeResult f) {

         if (f != SCOPE_SUCCESS)

                 s->result = f;

-        r = unit_kill_context(

+        /* If we have a controller set let's ask the controller nicely

+         * to terminate the scope, instead of us going directly into

+         * SIGTERM beserk mode */

+        if (state == SCOPE_STOP_SIGTERM)

+                skip_signal = bus_scope_send_request_stop(s) > 0;

+

+        if (!skip_signal) {

+                r = unit_kill_context(

                         UNIT(s),

                         &s->kill_context,

                         state != SCOPE_STOP_SIGTERM,

                         -1, -1, false);

-        if (r < 0)

-                goto fail;

+

+                if (r < 0)

+                        goto fail;

+        } else

+                r = 1;

         if (r > 0) {

                 if (s->timeout_stop_usec > 0) {

diff --git a/src/core/scope.h b/src/core/scope.h

index 2a3dcb7..b4bafa7 100644

--- a/src/core/scope.h

+++ b/src/core/scope.h

@@ -55,6 +55,8 @@ struct Scope {

         usec_t timeout_stop_usec;

+        char *controller;

+

         Set *pids;

         Watch timer_watch;

diff --git a/src/run/run.c b/src/run/run.c

index a6abead..93e3f88 100644

--- a/src/run/run.c

+++ b/src/run/run.c

@@ -315,6 +315,14 @@ static int start_transient_scope(

         if (r < 0)

                 return r;

+        {

+                const char *unique_id;

+                sd_bus_get_unique_name(bus, &unique_id);

+                r = sd_bus_message_append(m, "(sv)", "Controller", "s", unique_id);

+                if (r < 0)

+                        return r;

+        }

+

         r = sd_bus_message_append(m, "(sv)", "PIDs", "au", 1, (uint32_t) getpid());

         if (r < 0)

                 return r;

diff --git a/src/shared/dbus-common.c b/src/shared/dbus-common.c

index 3ba2d87..8a68708 100644

--- a/src/shared/dbus-common.c

+++ b/src/shared/dbus-common.c

@@ -1428,3 +1428,45 @@ const char *bus_message_get_sender_with_fallback(DBusMessage *m) {

         return ":no-sender";

 }

+

+bool bus_service_name_is_valid(const char *p) {

+        const char *q;

+        bool dot, found_dot = false, unique;

+

+        if (isempty(p))

+                return false;

+

+        unique = p[0] == ':';

+

+        for (dot = true, q = unique ? p+1 : p; *q; q++)

+                if (*q == '.') {

+                        if (dot)

+                                return false;

+

+                        found_dot = dot = true;

+                } else {

+                        bool good;

+

+                        good =

+                                (*q >= 'a' && *q <= 'z') ||

+                                (*q >= 'A' && *q <= 'Z') ||

+                                ((!dot || unique) && *q >= '0' && *q <= '9') ||

+                                *q == '_' || *q == '-';

+

+                        if (!good)

+                                return false;

+

+                        dot = false;

+                }

+

+        if (q - p > 255)

+                return false;

+

+        if (dot)

+                return false;

+

+        if (!found_dot)

+                return false;

+

+        return true;

+}

diff --git a/src/shared/dbus-common.h b/src/shared/dbus-common.h

index 9752f08..8d01d14 100644

--- a/src/shared/dbus-common.h

+++ b/src/shared/dbus-common.h

@@ -242,5 +242,7 @@ const char *bus_message_get_sender_with_fallback(DBusMessage *m);

 void bus_message_unrefp(DBusMessage **reply);

+bool bus_service_name_is_valid(const char *p);

+

 #define _cleanup_dbus_message_unref_ __attribute__((cleanup(bus_message_unrefp)))

 #define _cleanup_dbus_error_free_ __attribute__((cleanup(dbus_error_free)))