Merge pull request #9221 from poettering/bus-track-destroy

add sd_bus_track and sd_event_source destroy callbacks too

9 files changed, 247 insertions, 25 deletions

diff --git a/man/rules/meson.build b/man/rules/meson.build
index efbd940fe0..04f03c6786 100644
--- a/man/rules/meson.build
+++ b/man/rules/meson.build
@@ -233,7 +233,10 @@ manpages = [
  ['sd_bus_set_watch_bind', '3', ['sd_bus_get_watch_bind'], ''],
  ['sd_bus_slot_set_destroy_callback',
   '3',
-  ['sd_bus_slot_get_destroy_callback'],
+  ['sd_bus_destroy_t',
+   'sd_bus_slot_get_destroy_callback',
+   'sd_bus_track_get_destroy_callback',
+   'sd_bus_track_set_destroy_callback'],
   ''],
  ['sd_bus_slot_set_floating', '3', ['sd_bus_slot_get_floating'], ''],
  ['sd_bus_track_add_name',
@@ -277,9 +280,11 @@ manpages = [
    'sd_event_source',
    'sd_event_source_get_io_events',
    'sd_event_source_get_io_fd',
+   'sd_event_source_get_io_fd_own',
    'sd_event_source_get_io_revents',
    'sd_event_source_set_io_events',
-   'sd_event_source_set_io_fd'],
+   'sd_event_source_set_io_fd',
+   'sd_event_source_set_io_fd_own'],
   ''],
  ['sd_event_add_signal',
   '3',
@@ -314,6 +319,10 @@ manpages = [
   '3',
   ['sd_event_source_get_description'],
   ''],
+ ['sd_event_source_set_destroy_callback',
+  '3',
+  ['sd_event_destroy_t', 'sd_event_source_get_destroy_callback'],
+  ''],
  ['sd_event_source_set_enabled',
   '3',
   ['SD_EVENT_OFF',
diff --git a/man/sd_bus_slot_set_destroy_callback.xml b/man/sd_bus_slot_set_destroy_callback.xml
index 6334444f9a..a54b7e2d61 100644
--- a/man/sd_bus_slot_set_destroy_callback.xml
+++ b/man/sd_bus_slot_set_destroy_callback.xml
@@ -20,6 +20,9 @@
   <refnamediv>
     <refname>sd_bus_slot_set_destroy_callback</refname>
     <refname>sd_bus_slot_get_destroy_callback</refname>
+    <refname>sd_bus_track_set_destroy_callback</refname>
+    <refname>sd_bus_track_get_destroy_callback</refname>
+    <refname>sd_bus_destroy_t</refname>
 
     <refpurpose>Define the callback function for resource cleanup.</refpurpose>
   </refnamediv>
@@ -44,35 +47,54 @@
         <paramdef>sd_bus_slot *<parameter>slot</parameter></paramdef>
         <paramdef>sd_bus_destroy_t *<parameter>callback</parameter></paramdef>
       </funcprototype>
+
+      <funcprototype>
+        <funcdef>int <function>sd_bus_track_set_destroy_callback</function></funcdef>
+        <paramdef>sd_bus_track *<parameter>track</parameter></paramdef>
+        <paramdef>sd_bus_destroy_t <parameter>callback</parameter></paramdef>
+      </funcprototype>
+
+      <funcprototype>
+        <funcdef>int <function>sd_bus_track_get_destroy_callback</function></funcdef>
+        <paramdef>sd_bus_track *<parameter>track</parameter></paramdef>
+        <paramdef>sd_bus_destroy_t *<parameter>callback</parameter></paramdef>
+      </funcprototype>
     </funcsynopsis>
   </refsynopsisdiv>
 
   <refsect1>
     <title>Description</title>
 
-    <para><function>sd_bus_slot_set_destroy_callback()</function> sets
-    <parameter>callback</parameter> as the callback function to be called right before the bus slot
-    object <parameter>slot</parameter> is deallocated. The <parameter>userdata</parameter> pointer
-    from the slot object will be passed as the <parameter>userdata</parameter> parameter. This
-    pointer can be set specified as an argument to the constuctor functions, see
-    <citerefentry><refentrytitle>sd_bus_add_match</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
-    or directly, see
-    <citerefentry><refentrytitle>sd_bus_set_userdata</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
-    This callback function is called even if <parameter>userdata</parameter> is
-    <constant>NULL</constant>.</para>
+    <para><function>sd_bus_slot_set_destroy_callback()</function> sets <parameter>callback</parameter> as the callback
+    function to be called right before the bus slot object <parameter>slot</parameter> is deallocated. The
+    <parameter>userdata</parameter> pointer from the slot object will be passed as the <parameter>userdata</parameter>
+    parameter. This pointer can be set by an argument to the constructor functions, see
+    <citerefentry><refentrytitle>sd_bus_add_match</refentrytitle><manvolnum>3</manvolnum></citerefentry>, or directly,
+    see <citerefentry><refentrytitle>sd_bus_slot_set_userdata</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
+    This callback function is called even if <parameter>userdata</parameter> is <constant>NULL</constant>. Note that
+    this callback is invoked at a time where the bus slot object itself is already invalidated, and executing
+    operations or taking new references to the bus slot object is not permissible.</para>
 
     <para><function>sd_bus_slot_get_destroy_callback()</function> returns the current callback
     for <parameter>slot</parameter> in the <parameter>callback</parameter> parameter.</para>
+
+    <para><function>sd_bus_track_set_destroy_callback()</function> and
+    <function>sd_bus_track_get_destroy_callback</function> provide equivalent functionality for the
+    <parameter>userdata</parameter> pointer associated with bus peer tracking objects. For details about bus peer
+    tracking objects, see
+    <citerefentry><refentrytitle>sd_bus_track_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
   </refsect1>
 
   <refsect1>
     <title>Return Value</title>
 
-    <para>On success, <function>sd_bus_slot_set_destroy_callback()</function> returns 0 or a
-    positive integer. On failure, it returns a negative errno-style error code.</para>
+    <para>On success, <function>sd_bus_slot_set_destroy_callback()</function> and
+    <function>sd_bus_track_set_destroy_callback()</function> return 0 or a positive integer. On failure, they return a
+    negative errno-style error code.</para>
 
-    <para><function>sd_bus_slot_get_destroy_callback()</function> returns 1 if the destroy callback
-    function is set, 0 if not. On failure, it returns a negative errno-style error code.</para>
+    <para><function>sd_bus_slot_get_destroy_callback()</function> and
+    <function>sd_bus_track_get_destroy_callback</function> return positive if the destroy callback function is set, 0
+    if not. On failure, they return a negative errno-style error code.</para>
   </refsect1>
 
   <refsect1>
@@ -84,8 +106,8 @@
       <varlistentry>
         <term><constant>-EINVAL</constant></term>
 
-        <listitem><para>The <parameter>slot</parameter> parameter is <constant>NULL</constant>.
-        </para></listitem>
+        <listitem><para>The <parameter>slot</parameter> or <parameter>track</parameter> parameter is
+        <constant>NULL</constant>.</para></listitem>
       </varlistentry>
     </variablelist>
   </refsect1>
@@ -98,7 +120,11 @@
     <para>
       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
       <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
-      <citerefentry><refentrytitle>sd_bus_slot_set_floating</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+      <citerefentry><refentrytitle>sd_bus_slot_set_floating</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_bus_add_match</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_bus_track_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_bus_slot_set_userdata</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_bus_track_set_userdata</refentrytitle><manvolnum>3</manvolnum></citerefentry>
     </para>
   </refsect1>
 
diff --git a/man/sd_event_add_io.xml b/man/sd_event_add_io.xml
index d5ef462e53..bd513a7814 100644
--- a/man/sd_event_add_io.xml
+++ b/man/sd_event_add_io.xml
@@ -38,6 +38,8 @@
     <refname>sd_event_source_get_io_revents</refname>
     <refname>sd_event_source_get_io_fd</refname>
     <refname>sd_event_source_set_io_fd</refname>
+    <refname>sd_event_source_get_io_fd_own</refname>
+    <refname>sd_event_source_set_io_fd_own</refname>
     <refname>sd_event_source</refname>
     <refname>sd_event_io_handler_t</refname>
 
@@ -97,6 +99,17 @@
         <paramdef>int <parameter>fd</parameter></paramdef>
       </funcprototype>
 
+      <funcprototype>
+        <funcdef>int <function>sd_event_source_get_io_fd_own</function></funcdef>
+        <paramdef>sd_event_source *<parameter>source</parameter></paramdef>
+      </funcprototype>
+
+      <funcprototype>
+        <funcdef>int <function>sd_event_source_set_io_fd_own</function></funcdef>
+        <paramdef>sd_event_source *<parameter>source</parameter></paramdef>
+        <paramdef>int <parameter>b</parameter></paramdef>
+      </funcprototype>
+
     </funcsynopsis>
   </refsynopsisdiv>
 
@@ -212,6 +225,17 @@
     changes the UNIX file descriptor of an I/O event source created
     previously with <function>sd_event_add_io()</function>. It takes
     the event source object and the new file descriptor.</para>
+
+    <para><function>sd_event_source_set_io_fd_own()</function> controls whether the file descriptor of the event source
+    shall be closed automatically when the event source is freed, i.e. whether it shall be considered 'owned' by the
+    event source object. By default it is not closed automatically, and the application has to do this on its own. The
+    <parameter>b</parameter> parameter is a boolean parameter: if zero, the file descriptor is not closed automatically
+    when the event source is freed, otherwise it is closed.</para>
+
+    <para><function>sd_event_source_get_io_fd_own()</function> may be used to query the current setting of the file
+    descriptor ownership boolean flag as set with <function>sd_event_source_set_io_fd_own()</function>. It returns
+    positive if the file descriptor is closed automatically when the event source is destroyed, zero if not, and
+    negative on error.</para>
   </refsect1>
 
   <refsect1>
diff --git a/man/sd_event_source_set_destroy_callback.xml b/man/sd_event_source_set_destroy_callback.xml
new file mode 100644
index 0000000000..34f7652c86
--- /dev/null
+++ b/man/sd_event_source_set_destroy_callback.xml
@@ -0,0 +1,112 @@
+<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
+
+<!-- SPDX-License-Identifier: LGPL-2.1+ -->
+
+<refentry id="sd_event_source_set_destroy_callback"
+          xmlns:xi="http://www.w3.org/2001/XInclude">
+
+  <refentryinfo>
+    <title>sd_event_source_set_destroy_callback</title>
+    <productname>systemd</productname>
+  </refentryinfo>
+
+  <refmeta>
+    <refentrytitle>sd_event_source_set_destroy_callback</refentrytitle>
+    <manvolnum>3</manvolnum>
+  </refmeta>
+
+  <refnamediv>
+    <refname>sd_event_source_set_destroy_callback</refname>
+    <refname>sd_event_source_get_destroy_callback</refname>
+    <refname>sd_event_destroy_t</refname>
+
+    <refpurpose>Define the callback function for resource cleanup.</refpurpose>
+  </refnamediv>
+
+  <refsynopsisdiv>
+    <funcsynopsis>
+      <funcsynopsisinfo>#include &lt;systemd/sd-event.h&gt;</funcsynopsisinfo>
+
+      <funcprototype>
+        <funcdef>typedef int (*<function>sd_event_destroy_t</function>)</funcdef>
+        <paramdef>void *<parameter>userdata</parameter></paramdef>
+      </funcprototype>
+
+      <funcprototype>
+        <funcdef>int <function>sd_event_source_set_destroy_callback</function></funcdef>
+        <paramdef>sd_event_source *<parameter>source</parameter></paramdef>
+        <paramdef>sd_event_destroy_t <parameter>callback</parameter></paramdef>
+      </funcprototype>
+
+      <funcprototype>
+        <funcdef>int <function>sd_event_source_get_destroy_callback</function></funcdef>
+        <paramdef>sd_event_source *<parameter>source</parameter></paramdef>
+        <paramdef>sd_event_destroy_t *<parameter>callback</parameter></paramdef>
+      </funcprototype>
+
+    </funcsynopsis>
+  </refsynopsisdiv>
+
+  <refsect1>
+    <title>Description</title>
+
+    <para><function>sd_event_source_set_destroy_callback()</function> sets <parameter>callback</parameter> as the
+    callback function to be called right before the event source object <parameter>source</parameter> is
+    deallocated. The <parameter>userdata</parameter> pointer from the event source object will be passed as the
+    <parameter>userdata</parameter> parameter. This pointer can be set by an argument to the constructor functions, see
+    <citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry>, or directly,
+    see
+    <citerefentry><refentrytitle>sd_event_source_set_userdata</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
+    This callback function is called even if <parameter>userdata</parameter> is <constant>NULL</constant>. Note that
+    this callback is invoked at a time where the event source object itself is already invalidated, and executing
+    operations or taking new references to the event source object is not permissible.</para>
+
+    <para><function>sd_event_source_get_destroy_callback()</function> returns the current callback
+    for <parameter>source</parameter> in the <parameter>callback</parameter> parameter.</para>
+  </refsect1>
+
+  <refsect1>
+    <title>Return Value</title>
+
+    <para>On success, <function>sd_event_source_set_destroy_callback()</function> returns 0 or a positive integer. On
+    failure, it returns a negative errno-style error code.</para>
+
+    <para><function>sd_event_source_get_destroy_callback()</function> returns positive if the destroy callback function
+    is set, 0 if not. On failure, returns a negative errno-style error code.</para>
+  </refsect1>
+
+  <refsect1>
+    <title>Errors</title>
+
+    <para>Returned errors may indicate the following problems:</para>
+
+    <variablelist>
+      <varlistentry>
+        <term><constant>-EINVAL</constant></term>
+
+        <listitem><para>The <parameter>source</parameter> parameter is <constant>NULL</constant>.</para></listitem>
+      </varlistentry>
+    </variablelist>
+  </refsect1>
+
+  <xi:include href="libsystemd-pkgconfig.xml" />
+
+  <refsect1>
+    <title>See Also</title>
+
+    <para>
+      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_event_add_time</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_event_add_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_event_add_child</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_event_add_inotify</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_event_add_defer</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_event_source_set_userdata</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+    </para>
+  </refsect1>
+
+</refentry>
diff --git a/src/libsystemd/libsystemd.sym b/src/libsystemd/libsystemd.sym
index dc9c2d241a..270fe37e9f 100644
--- a/src/libsystemd/libsystemd.sym
+++ b/src/libsystemd/libsystemd.sym
@@ -565,6 +565,10 @@ global:
         sd_bus_slot_set_floating;
         sd_bus_slot_get_destroy_callback;
         sd_bus_slot_set_destroy_callback;
+        sd_bus_track_get_destroy_callback;
+        sd_bus_track_set_destroy_callback;
         sd_event_add_inotify;
         sd_event_source_get_inotify_mask;
+        sd_event_source_set_destroy_callback;
+        sd_event_source_get_destroy_callback;
 } LIBSYSTEMD_238;
diff --git a/src/libsystemd/sd-bus/bus-track.c b/src/libsystemd/sd-bus/bus-track.c
index 168c6c5ac7..1819eaffd4 100644
--- a/src/libsystemd/sd-bus/bus-track.c
+++ b/src/libsystemd/sd-bus/bus-track.c
@@ -31,6 +31,7 @@ struct sd_bus_track {
         bool in_queue:1;   /* In bus->track_queue? */
         bool modified:1;
         bool recursive:1;
+        sd_bus_destroy_t destroy_callback;
 
         LIST_FIELDS(sd_bus_track, tracks);
 };
@@ -164,18 +165,21 @@ _public_ sd_bus_track* sd_bus_track_unref(sd_bus_track *track) {
                 return NULL;
 
         assert(track->n_ref > 0);
+        track->n_ref--;
 
-        if (track->n_ref > 1) {
-                track->n_ref--;
+        if (track->n_ref > 0)
                 return NULL;
-        }
 
         if (track->in_list)
                 LIST_REMOVE(tracks, track->bus->tracks, track);
 
         bus_track_remove_from_queue(track);
-        hashmap_free_with_destructor(track->names, track_item_free);
-        sd_bus_unref(track->bus);
+        track->names = hashmap_free_with_destructor(track->names, track_item_free);
+        track->bus = sd_bus_unref(track->bus);
+
+        if (track->destroy_callback)
+                track->destroy_callback(track->userdata);
+
         return mfree(track);
 }
 
@@ -439,6 +443,22 @@ _public_ void *sd_bus_track_set_userdata(sd_bus_track *track, void *userdata) {
         return ret;
 }
 
+_public_ int sd_bus_track_set_destroy_callback(sd_bus_track *track, sd_bus_destroy_t callback) {
+        assert_return(track, -EINVAL);
+
+        track->destroy_callback = callback;
+        return 0;
+}
+
+_public_ int sd_bus_track_get_destroy_callback(sd_bus_track *track, sd_bus_destroy_t *ret) {
+        assert_return(track, -EINVAL);
+
+        if (ret)
+                *ret = track->destroy_callback;
+
+        return !!track->destroy_callback;
+}
+
 _public_ int sd_bus_track_set_recursive(sd_bus_track *track, int b) {
         assert_return(track, -EINVAL);
 
diff --git a/src/libsystemd/sd-event/sd-event.c b/src/libsystemd/sd-event/sd-event.c
index 1b983dbe37..196b90d59b 100644
--- a/src/libsystemd/sd-event/sd-event.c
+++ b/src/libsystemd/sd-event/sd-event.c
@@ -106,6 +106,8 @@ struct sd_event_source {
         uint64_t pending_iteration;
         uint64_t prepare_iteration;
 
+        sd_event_destroy_t destroy_callback;
+
         LIST_FIELDS(sd_event_source, sources);
 
         union {
@@ -1016,7 +1018,10 @@ static void source_free(sd_event_source *s) {
         source_disconnect(s);
 
         if (s->type == SOURCE_IO && s->io.owned)
-                safe_close(s->io.fd);
+                s->io.fd = safe_close(s->io.fd);
+
+        if (s->destroy_callback)
+                s->destroy_callback(s->userdata);
 
         free(s->description);
         free(s);
@@ -3775,3 +3780,19 @@ _public_ int sd_event_get_iteration(sd_event *e, uint64_t *ret) {
         *ret = e->iteration;
         return 0;
 }
+
+_public_ int sd_event_source_set_destroy_callback(sd_event_source *s, sd_event_destroy_t callback) {
+        assert_return(s, -EINVAL);
+
+        s->destroy_callback = callback;
+        return 0;
+}
+
+_public_ int sd_event_source_get_destroy_callback(sd_event_source *s, sd_event_destroy_t *ret) {
+        assert_return(s, -EINVAL);
+
+        if (ret)
+                *ret = s->destroy_callback;
+
+        return !!s->destroy_callback;
+}
diff --git a/src/systemd/sd-bus.h b/src/systemd/sd-bus.h
index b2394763c1..a1b1570663 100644
--- a/src/systemd/sd-bus.h
+++ b/src/systemd/sd-bus.h
@@ -485,6 +485,9 @@ const char* sd_bus_track_contains(sd_bus_track *track, const char *name);
 const char* sd_bus_track_first(sd_bus_track *track);
 const char* sd_bus_track_next(sd_bus_track *track);
 
+int sd_bus_track_set_destroy_callback(sd_bus_track *s, sd_bus_destroy_t callback);
+int sd_bus_track_get_destroy_callback(sd_bus_track *s, sd_bus_destroy_t *ret);
+
 /* Define helpers so that __attribute__((cleanup(sd_bus_unrefp))) and similar may be used. */
 _SD_DEFINE_POINTER_CLEANUP_FUNC(sd_bus, sd_bus_unref);
 _SD_DEFINE_POINTER_CLEANUP_FUNC(sd_bus, sd_bus_flush_close_unref);
diff --git a/src/systemd/sd-event.h b/src/systemd/sd-event.h
index 28939ca550..fc5a75b6b6 100644
--- a/src/systemd/sd-event.h
+++ b/src/systemd/sd-event.h
@@ -80,6 +80,7 @@ typedef int (*sd_event_child_handler_t)(sd_event_source *s, const siginfo_t *si,
 typedef void* sd_event_child_handler_t;
 #endif
 typedef int (*sd_event_inotify_handler_t)(sd_event_source *s, const struct inotify_event *event, void *userdata);
+typedef void (*sd_event_destroy_t)(void *userdata);
 
 int sd_event_default(sd_event **e);
 
@@ -143,6 +144,8 @@ int sd_event_source_get_time_clock(sd_event_source *s, clockid_t *clock);
 int sd_event_source_get_signal(sd_event_source *s);
 int sd_event_source_get_child_pid(sd_event_source *s, pid_t *pid);
 int sd_event_source_get_inotify_mask(sd_event_source *s, uint32_t *ret);
+int sd_event_source_set_destroy_callback(sd_event_source *s, sd_event_destroy_t callback);
+int sd_event_source_get_destroy_callback(sd_event_source *s, sd_event_destroy_t *ret);
 
 /* Define helpers so that __attribute__((cleanup(sd_event_unrefp))) and similar may be used. */
 _SD_DEFINE_POINTER_CLEANUP_FUNC(sd_event, sd_event_unref);