sd-event: add destroy callback logic to sd-event too

This adds what has been added to sd_bus_slot and sd_bus_track to
sd_event too.

diff --git a/man/rules/meson.build b/man/rules/meson.build
index 88c832815ff3698fcad5c79a9d704d51926fd942..13295da9d36e82effb7f494d7783048d09c6597d 100644 (file)
--- a/man/rules/meson.build
+++ b/man/rules/meson.build
@@ -317,6 +317,10 @@ 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_event_source_set_destroy_callback.xml b/man/sd_event_source_set_destroy_callback.xml
new file mode 100644 (file)
index 0000000..aa6d0e1
--- /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>elogind</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;elogind/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="libelogind-pkgconfig.xml" />
+
+  <refsect1>
+    <title>See Also</title>
+
+    <para>
+      <citerefentry><refentrytitle>elogind</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/libelogind/libelogind.sym b/src/libelogind/libelogind.sym
index e65c0d1b849c7a36135146e477ac75f3aacb37aa..e63668b2a1a2d4695f7245b19e1fb19753452422 100644 (file)
--- a/src/libelogind/libelogind.sym
+++ b/src/libelogind/libelogind.sym
@@ -575,4 +575,6 @@ global:
         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/libelogind/sd-event/sd-event.c b/src/libelogind/sd-event/sd-event.c
index 3f9691227d9907f364911c45442d07e09c8cf8fd..ca104281e5456096759138f0634052ea6cae0483 100644 (file)
--- a/src/libelogind/sd-event/sd-event.c
+++ b/src/libelogind/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-event.h b/src/systemd/sd-event.h
index 422393888285240e5114a6397e43d1734a7e6922..e6bea9d4082d29422aa0e7603549ebb8c90abd32 100644 (file)
--- 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);