Merge pull request #15503 from DaanDeMeyer/sd-bus-get-docs
sd-bus: Add sd_bus_get_scope/tid/unique_name docs
This commit is contained in:
Zbigniew Jędrzejewski-Szmek
@@ -379,6 +379,9 @@ manpages = [
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'3',
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['sd_bus_get_allow_interactive_authorization',
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'sd_bus_get_description',
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'sd_bus_get_scope',
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'sd_bus_get_tid',
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'sd_bus_get_unique_name',
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'sd_bus_is_anonymous',
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'sd_bus_is_trusted',
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'sd_bus_set_allow_interactive_authorization',
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@@ -80,6 +80,9 @@
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<citerefentry><refentrytitle>sd_bus_get_fd</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_bus_get_method_call_timeout</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_bus_get_n_queued_read</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_bus_get_scope</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_bus_get_tid</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_bus_get_unique_name</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_bus_is_bus_client</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_bus_is_server</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_bus_message_append</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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+58
-48
@@ -26,7 +26,8 @@
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<refname>sd_bus_get_events</refname>
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<refname>sd_bus_get_timeout</refname>
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<refpurpose>Get the file descriptor, I/O events and time-out to wait for from a message bus object</refpurpose>
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<refpurpose>Get the file descriptor, I/O events and time-out to wait for from a message bus
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object</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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@@ -61,65 +62,74 @@
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<refsect1>
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<title>Description</title>
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<para><function>sd_bus_get_fd()</function> returns the file descriptor used to communicate from a message bus
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object. This descriptor can be used with <citerefentry
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project='man-pages'><refentrytitle>poll</refentrytitle><manvolnum>3</manvolnum></citerefentry> or a similar
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function to wait for I/O events on the specified bus connection object. If the bus object was configured with the
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<function>sd_bus_set_fd()</function> function, then the <parameter>input_fd</parameter> file descriptor used in
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that call is returned.</para>
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<para><function>sd_bus_get_fd()</function> returns the file descriptor used to communicate from
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a message bus object. This descriptor can be used with
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<citerefentry project='man-pages'><refentrytitle>poll</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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or a similar function to wait for I/O events on the specified bus connection object. If the bus
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object was configured with the <function>sd_bus_set_fd()</function> function, then the
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<parameter>input_fd</parameter> file descriptor used in that call is returned.</para>
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<para><function>sd_bus_set_fd()</function> sets the file descriptors used to communicate from a message bus
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object. Both <parameter>input_fd</parameter> and <parameter>output_fd</parameter> must be valid file descriptors.
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The same file descriptor may be used as both the input and the output file descriptor. This function must be called
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before the bus is started.</para>
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<para><function>sd_bus_set_fd()</function> sets the file descriptors used to communicate from a
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message bus object. Both <parameter>input_fd</parameter> and <parameter>output_fd</parameter>
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must be valid file descriptors. The same file descriptor may be used as both the input and the
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output file descriptor. This function must be called before the bus is started.</para>
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<para><function>sd_bus_get_events()</function> returns the I/O events to wait for, suitable for passing to
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<function>poll()</function> or a similar call. Returns a combination of <constant>POLLIN</constant>,
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<constant>POLLOUT</constant>, … events, or negative on error.</para>
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<para><function>sd_bus_get_events()</function> returns the I/O events to wait for, suitable for
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passing to <function>poll()</function> or a similar call. Returns a combination of
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<constant>POLLIN</constant>, <constant>POLLOUT</constant>, … events, or negative on error.
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</para>
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<para><function>sd_bus_get_timeout()</function> returns the time-out in µs to pass to to
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<function>poll()</function> or a similar call when waiting for events on the specified bus connection. The returned
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time-out may be zero, in which case a subsequent I/O polling call should be invoked in non-blocking mode. The
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returned timeout may be <constant>UINT64_MAX</constant> in which case the I/O polling call may block indefinitely,
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without any applied time-out. Note that the returned time-out should be considered only a maximum sleeping time. It
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is permissible (and even expected) that shorter time-outs are used by the calling program, in case other event
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sources are polled in the same event loop. Note that the returned time-value is relative and specified in
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microseconds. When converting this value in order to pass it as third argument to <function>poll()</function>
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(which expects milliseconds), care should be taken to use a division that rounds up to ensure the I/O polling
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operation doesn't sleep for shorter than necessary, which might result in unintended busy looping (alternatively,
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use <citerefentry project='man-pages'><refentrytitle>ppoll</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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instead of plain <function>poll()</function>, which understands time-outs with nano-second granularity).</para>
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<function>poll()</function> or a similar call when waiting for events on the specified bus
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connection. The returned time-out may be zero, in which case a subsequent I/O polling call
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should be invoked in non-blocking mode. The returned timeout may be
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<constant>UINT64_MAX</constant> in which case the I/O polling call may block indefinitely,
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without any applied time-out. Note that the returned time-out should be considered only a
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maximum sleeping time. It is permissible (and even expected) that shorter time-outs are used by
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the calling program, in case other event sources are polled in the same event loop. Note that
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the returned time-value is relative and specified in microseconds. When converting this value in
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order to pass it as third argument to <function>poll()</function> (which expects milliseconds),
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care should be taken to use a division that rounds up to ensure the I/O polling operation
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doesn't sleep for shorter than necessary, which might result in unintended busy looping
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(alternatively, use
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<citerefentry project='man-pages'><refentrytitle>ppoll</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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instead of plain <function>poll()</function>, which understands time-outs with nano-second
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granularity).</para>
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<para>These three functions are useful to hook up a bus connection object with an external or manual event loop
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involving <function>poll()</function> or a similar I/O polling call. Before each invocation of the I/O polling
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call, all three functions should be invoked: the file descriptor returned by <function>sd_bus_get_fd()</function>
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should be polled for the events indicated by <function>sd_bus_get_events()</function>, and the I/O call should
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block for that up to the time-out returned by <function>sd_bus_get_timeout()</function>. After each I/O polling
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<para>These three functions are useful to hook up a bus connection object with an external or
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manual event loop involving <function>poll()</function> or a similar I/O polling call. Before
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each invocation of the I/O polling call, all three functions should be invoked: the file
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descriptor returned by <function>sd_bus_get_fd()</function> should be polled for the events
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indicated by <function>sd_bus_get_events()</function>, and the I/O call should block for that up
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to the time-out returned by <function>sd_bus_get_timeout()</function>. After each I/O polling
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call the bus connection needs to process incoming or outgoing data, by invoking
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<citerefentry><refentrytitle>sd_bus_process</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
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<citerefentry><refentrytitle>sd_bus_process</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
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</para>
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<para>Note that these function are only one of three supported ways to implement I/O event handling for bus
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connections. Alternatively use
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<citerefentry><refentrytitle>sd_bus_attach_event</refentrytitle><manvolnum>3</manvolnum></citerefentry> to attach a
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bus connection to an <citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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event loop. Or use <citerefentry><refentrytitle>sd_bus_wait</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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<para>Note that these functions are only one of three supported ways to implement I/O event
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handling for bus connections. Alternatively use
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<citerefentry><refentrytitle>sd_bus_attach_event</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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to attach a bus connection to an
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<citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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event loop. Or use
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<citerefentry><refentrytitle>sd_bus_wait</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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as a simple synchronous, blocking I/O waiting call.</para>
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</refsect1>
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<refsect1>
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<title>Return Value</title>
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<para>On success, <function>sd_bus_get_fd()</function> returns the file descriptor used for communication. On failure,
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it returns a negative errno-style error code.</para>
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<para>On success, <function>sd_bus_get_fd()</function> returns the file descriptor used for
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communication. On failure, it returns a negative errno-style error code.</para>
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<para>On success, <function>sd_bus_set_fd()</function> returns a non-negative integer. On failure, it returns a
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negative errno-style error code.</para>
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<para>On success, <function>sd_bus_set_fd()</function> returns a non-negative integer. On
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failure, it returns a negative errno-style error code.</para>
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<para>On success, <function>sd_bus_get_events()</function> returns the I/O event mask to use for I/O event watching.
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On failure, it returns a negative errno-style error code.</para>
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<para>On success, <function>sd_bus_get_events()</function> returns the I/O event mask to use for
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I/O event watching. On failure, it returns a negative errno-style error code.</para>
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<para>On success, <function>sd_bus_get_timeout()</function> returns a non-negative integer. On failure, it returns a
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negative errno-style error code.</para>
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<para>On success, <function>sd_bus_get_timeout()</function> returns a non-negative integer. On
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failure, it returns a negative errno-style error code.</para>
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<refsect2>
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<title>Errors</title>
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@@ -136,8 +146,8 @@
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<varlistentry>
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<term><constant>-ECHILD</constant></term>
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<listitem><para>The bus connection was allocated in a parent process and is being reused in a child
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process after <function>fork()</function>.</para></listitem>
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<listitem><para>The bus connection was allocated in a parent process and is being reused
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in a child process after <function>fork()</function>.</para></listitem>
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</varlistentry>
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<varlistentry>
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@@ -157,8 +167,8 @@
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<varlistentry>
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<term><constant>-EBADF</constant></term>
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<listitem><para>An invalid file descriptor was passed to <function>sd_bus_set_fd()</function>.
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</para></listitem>
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<listitem><para>An invalid file descriptor was passed to
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<function>sd_bus_set_fd()</function>.</para></listitem>
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</varlistentry>
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<varlistentry>
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@@ -24,6 +24,9 @@
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<refname>sd_bus_is_trusted</refname>
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<refname>sd_bus_set_allow_interactive_authorization</refname>
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<refname>sd_bus_get_allow_interactive_authorization</refname>
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<refname>sd_bus_get_scope</refname>
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<refname>sd_bus_get_tid</refname>
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<refname>sd_bus_get_unique_name</refname>
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<refpurpose>Set or query properties of a bus object</refpurpose>
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</refnamediv>
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@@ -76,59 +79,94 @@
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<funcdef>int <function>sd_bus_get_allow_interactive_authorization</function></funcdef>
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<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_bus_get_scope</function></funcdef>
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<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
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<paramdef>const char **<parameter>scope</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_bus_get_tid</function></funcdef>
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<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
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<paramdef>pid_t *<parameter>tid</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_bus_get_unique_name</function></funcdef>
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<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
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<paramdef>const char **<parameter>unique</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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</refsynopsisdiv>
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<refsect1>
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<title>Description</title>
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<para><function>sd_bus_set_description()</function> sets the description string
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that is used in logging to the specified string. The string is copied internally
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and freed when the bus object is deallocated. The
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<parameter>description</parameter> argument may be <constant>NULL</constant>, in
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which case the description is unset. This function must be called before the bus
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is started.</para>
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<para><function>sd_bus_set_description()</function> sets the description string that is used in
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logging to the specified string. The string is copied internally and freed when the bus object
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is deallocated. The <parameter>description</parameter> argument may be
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<constant>NULL</constant>, in which case the description is unset. This function must be called
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before the bus is started.</para>
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<para><function>sd_bus_get_description()</function> returns a description string
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in <parameter>description</parameter>. This string may have been previously set
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with <function>sd_bus_set_description()</function> or
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<para><function>sd_bus_get_description()</function> returns a description string in
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<parameter>description</parameter>. This string may have been previously set with
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<function>sd_bus_set_description()</function> or
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<citerefentry><refentrytitle>sd_bus_open_with_description</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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or similar. If not set this way, a default string like <literal>system</literal>
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or <literal>user</literal> will be returned for the system or user buses,
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and <constant>NULL</constant> otherwise.</para>
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or similar. If not set this way, a default string like <literal>system</literal> or
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<literal>user</literal> will be returned for the system or user buses, and
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<constant>NULL</constant> otherwise.</para>
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<para><function>sd_bus_set_anonymous()</function> enables or disables "anonymous
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authentication", i.e. lack of authentication, of the bus peer. This function must
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be called before the bus is started. See the <ulink
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url="view-source:https://dbus.freedesktop.org/doc/dbus-specification.html#auth-mechanisms">Authentication
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Mechanisms</ulink> section of the D-Bus specification for details.</para>
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<para><function>sd_bus_set_anonymous()</function> enables or disables "anonymous authentication",
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i.e. lack of authentication, of the bus peer. This function must be called before the bus is
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started. See the
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<ulink url="view-source:https://dbus.freedesktop.org/doc/dbus-specification.html#auth-mechanisms">
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Authentication Mechanisms</ulink> section of the D-Bus specification for details.</para>
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<para><function>sd_bus_is_anonymous()</function> returns true if the bus connection allows anonymous
|
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authentication (in the sense described in previous paragraph).</para>
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<para><function>sd_bus_is_anonymous()</function> returns true if the bus connection allows
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anonymous authentication (in the sense described in previous paragraph).</para>
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<para><function>sd_bus_set_trusted()</function> sets the "trusted" state on the
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<parameter>bus</parameter> object. If true, all connections on the bus are
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trusted and access to all privileged and unprivileged methods is granted. This
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function must be called before the bus is started.</para>
|
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<parameter>bus</parameter> object. If true, all connections on the bus are trusted and access to
|
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all privileged and unprivileged methods is granted. This function must be called before the bus
|
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is started.</para>
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<para><function>sd_bus_is_trusted()</function> returns true if the bus connection is trusted (in the
|
||||
sense described in previous paragraph).</para>
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<para><function>sd_bus_is_trusted()</function> returns true if the bus connection is trusted (in
|
||||
the sense described in previous paragraph).</para>
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|
||||
<para><function>sd_bus_set_allow_interactive_authorization()</function>
|
||||
enables or disables interactive authorization for method calls. If true,
|
||||
messages are marked with the
|
||||
<para><function>sd_bus_set_allow_interactive_authorization()</function> enables or disables
|
||||
interactive authorization for method calls. If true, messages are marked with the
|
||||
<constant>ALLOW_INTERACTIVE_AUTHORIZATION</constant> flag specified by the
|
||||
<ulink
|
||||
url="view-source:https://dbus.freedesktop.org/doc/dbus-specification.html">D-Bus</ulink>
|
||||
specification, informing the receiving side that the caller is prepared to
|
||||
wait for interactive authorization, which might take a considerable time to
|
||||
complete. If this flag is set, the user may be queried for passwords or
|
||||
confirmation via <ulink
|
||||
url="http://www.freedesktop.org/wiki/Software/polkit">polkit</ulink> or a
|
||||
similar framework.</para>
|
||||
<ulink url="view-source:https://dbus.freedesktop.org/doc/dbus-specification.html">D-Bus</ulink>
|
||||
specification, informing the receiving side that the caller is prepared to wait for interactive
|
||||
authorization, which might take a considerable time to complete. If this flag is set, the user
|
||||
may be queried for passwords or confirmation via
|
||||
<ulink url="http://www.freedesktop.org/wiki/Software/polkit">polkit</ulink> or a similar
|
||||
framework.</para>
|
||||
|
||||
<para><function>sd_bus_get_allow_interactive_authorization()</function> returns
|
||||
true if interactive authorization is allowed and false if not.</para>
|
||||
<para><function>sd_bus_get_allow_interactive_authorization()</function> returns true if
|
||||
interactive authorization is allowed and false if not.</para>
|
||||
|
||||
<para><function>sd_bus_get_scope()</function> stores the scope of the given bus object in
|
||||
<parameter>scope</parameter>. The scope of the system bus is <literal>system</literal>. The
|
||||
scope of a user session bus is <literal>user</literal>. If the given bus object is not the
|
||||
system or a user session bus, <function>sd_bus_get_scope()</function> returns an error.</para>
|
||||
|
||||
<para><function>sd_bus_get_tid()</function> stores the kernel thread id of the thread associated
|
||||
with the given bus object in <parameter>tid</parameter>. If <parameter>bus</parameter> is a
|
||||
default bus object obtained by calling one of the functions of the
|
||||
<citerefentry><refentrytitle>sd_bus_default</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
||||
family of functions, it stores the thread id of the thread the bus object was created in.
|
||||
Otherwise, if the bus object is attached to an event loop, it stores the thread id of the
|
||||
thread the event loop object was created in. If <parameter>bus</parameter> is not a default bus
|
||||
object and is not attached to an event loop, <function>sd_bus_get_tid()</function> returns an
|
||||
error.</para>
|
||||
|
||||
<para><function>sd_bus_get_unique_name()</function> stores the unique name of the bus object on
|
||||
the bus in <parameter>unique</parameter>. See
|
||||
<ulink url="https://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-names-bus">
|
||||
The D-Bus specification</ulink> for more information on bus names. Note that the caller does not
|
||||
own the string stored in <parameter>unique</parameter> and should not free it.</para>
|
||||
</refsect1>
|
||||
|
||||
<refsect1>
|
||||
@@ -172,8 +210,21 @@
|
||||
|
||||
<listitem><para>Memory allocation failed.</para></listitem>
|
||||
</varlistentry>
|
||||
</variablelist>
|
||||
|
||||
<varlistentry>
|
||||
<term><constant>-ENODATA</constant></term>
|
||||
|
||||
<listitem><para>The bus object passed to <function>sd_bus_get_scope()</function> was not a
|
||||
system or user session bus.</para></listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term><constant>-ENXIO</constant></term>
|
||||
|
||||
<listitem><para>The bus object passed to <function>sd_bus_get_tid()</function> was not a
|
||||
default bus object and is not attached to an event loop.</para></listitem>
|
||||
</varlistentry>
|
||||
</variablelist>
|
||||
</refsect2>
|
||||
</refsect1>
|
||||
|
||||
|
||||
Reference in New Issue
Block a user