-<?xml version='1.0'?> <!--*-nxml-*-->
+<?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">
<refname>sd_pid_get_owner_uid</refname>
<refname>sd_pid_get_machine_name</refname>
<refname>sd_pid_get_slice</refname>
+ <refname>sd_pid_get_user_slice</refname>
+ <refname>sd_pid_get_cgroup</refname>
<refname>sd_peer_get_session</refname>
<refname>sd_peer_get_unit</refname>
<refname>sd_peer_get_user_unit</refname>
<refname>sd_peer_get_owner_uid</refname>
<refname>sd_peer_get_machine_name</refname>
<refname>sd_peer_get_slice</refname>
- <refpurpose>Determine session, service, owner of a
- session, container/VM or slice of a specific
- PID or socket peer</refpurpose>
+ <refname>sd_peer_get_user_slice</refname>
+ <refname>sd_peer_get_cgroup</refname>
+ <refpurpose>Determine session, unit, owner of a session,
+ container/VM or slice of a specific PID or socket
+ peer</refpurpose>
</refnamediv>
<refsynopsisdiv>
<paramdef>char **<parameter>slice</parameter></paramdef>
</funcprototype>
+ <funcprototype>
+ <funcdef>int <function>sd_pid_get_user_slice</function></funcdef>
+ <paramdef>pid_t <parameter>pid</parameter></paramdef>
+ <paramdef>char **<parameter>slice</parameter></paramdef>
+ </funcprototype>
+
+ <funcprototype>
+ <funcdef>int <function>sd_pid_get_cgroup</function></funcdef>
+ <paramdef>pid_t <parameter>pid</parameter></paramdef>
+ <paramdef>char **<parameter>cgroup</parameter></paramdef>
+ </funcprototype>
+
<funcprototype>
<funcdef>int <function>sd_peer_get_session</function></funcdef>
<paramdef>int <parameter>fd</parameter></paramdef>
<paramdef>int <parameter>fd</parameter></paramdef>
<paramdef>char **<parameter>slice</parameter></paramdef>
</funcprototype>
+
+ <funcprototype>
+ <funcdef>int <function>sd_peer_get_user_slice</function></funcdef>
+ <paramdef>int <parameter>fd</parameter></paramdef>
+ <paramdef>char **<parameter>slice</parameter></paramdef>
+ </funcprototype>
+
+ <funcprototype>
+ <funcdef>int <function>sd_peer_get_cgroup</function></funcdef>
+ <paramdef>int <parameter>fd</parameter></paramdef>
+ <paramdef>char **<parameter>cgroup</parameter></paramdef>
+ </funcprototype>
</funcsynopsis>
</refsynopsisdiv>
not all processes are part of a login session (e.g. system service
processes, user processes that are shared between multiple
sessions of the same user, or kernel threads). For processes not
- being part of a login session this function will fail. The
- returned string needs to be freed with the libc
- <citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ being part of a login session, this function will fail with
+ -ENODATA. The returned string needs to be freed with the libc
+ <citerefentry
+ project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
call after use.</para>
<para><function>sd_pid_get_unit()</function> may be used to
- determine the systemd system unit (i.e. system service) identifier
- of a process identified by the specified PID. The unit name is a
- short string, suitable for usage in file system paths. Note that
- not all processes are part of a system unit/service (e.g. user
- processes, or kernel threads). For processes not being part of a
- systemd system unit this function will fail. (More specifically:
- this call will not work for processes that are part of user units,
- use <function>sd_pid_get_user_unit()</function> for that.) The
- returned string needs to be freed with the libc
- <citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ determine the systemd system unit (i.e. system service or scope
+ unit) identifier of a process identified by the specified PID. The
+ unit name is a short string, suitable for usage in file system
+ paths. Note that not all processes are part of a system
+ unit/service (e.g. user processes, or kernel threads). For
+ processes not being part of a systemd system unit, this function
+ will fail with -ENODATA. (More specifically, this call will not
+ work for kernel threads.) The returned string needs to be freed
+ with the libc <citerefentry
+ project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
call after use.</para>
<para><function>sd_pid_get_user_unit()</function> may be used to
- determine the systemd user unit (i.e. user service) identifier of
- a process identified by the specified PID. This is similar to
- <function>sd_pid_get_unit()</function> but applies to user units
- instead of system units.</para>
+ determine the systemd user unit (i.e. user service or scope unit)
+ identifier of a process identified by the specified PID. This is
+ similar to <function>sd_pid_get_unit()</function>, but applies to
+ user units instead of system units.</para>
<para><function>sd_pid_get_owner_uid()</function> may be used to
- determine the Unix user identifier of the owner of the session of
- a process identified the specified PID. Note that this function
- will succeed for user processes which are shared between multiple
- login sessions of the same user, where
+ determine the Unix UID (user identifier) of the owner of the
+ session of a process identified the specified PID. Note that this
+ function will succeed for user processes which are shared between
+ multiple login sessions of the same user, whereas
<function>sd_pid_get_session()</function> will fail. For processes
not being part of a login session and not being a shared process
- of a user this function will fail.</para>
+ of a user, this function will fail with -ENODATA.</para>
<para><function>sd_pid_get_machine_name()</function> may be used
to determine the name of the VM or container is a member of. The
machine name is a short string, suitable for usage in file system
paths. The returned string needs to be freed with the libc
- <citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- call after use.</para>
+ <citerefentry
+ project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ call after use. For processes not part of a VM or containers, this
+ function fails with -ENODATA.</para>
<para><function>sd_pid_get_slice()</function> may be used to
determine the slice unit the process is a member of. See
<citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
call after use.</para>
+ <para>Similarly, <function>sd_pid_get_user_slice()</function>
+ returns the user slice (as managed by the user's systemd instance)
+ of a process.</para>
+
+ <para><function>sd_pid_get_cgroup()</function> returns the control
+ group path of the specified process, relative to the root of the
+ hierarchy. Returns the path without trailing slash, except for
+ processes located in the root control group, where "/" is
+ returned. To find the actual control group path in the file system,
+ the returned path needs to be prefixed with
+ <filename>/sys/fs/cgroup/</filename> (if the unified control group
+ setup is used), or
+ <filename>/sys/fs/cgroup/<replaceable>HIERARCHY</replaceable>/</filename>
+ (if the legacy multi-hierarchy control group setup is used).</para>
+
<para>If the <varname>pid</varname> parameter of any of these
functions is passed as 0, the operation is executed for the
calling process.</para>
<function>sd_peer_get_unit()</function>,
<function>sd_peer_get_user_unit()</function>,
<function>sd_peer_get_owner_uid()</function>,
- <function>sd_peer_get_machine_name()</function> and
- <function>sd_peer_get_slice()</function> calls operate similar to
+ <function>sd_peer_get_machine_name()</function>,
+ <function>sd_peer_get_slice()</function>,
+ <function>sd_peer_get_user_slice()</function> and
+ <function>sd_peer_get_cgroup()</function> calls operate similar to
their PID counterparts, but operate on a connected AF_UNIX socket
- and retrieve information about the connected peer process.</para>
+ and retrieve information about the connected peer process. Note
+ that these fields are retrieved via <filename>/proc</filename>,
+ and hence are not suitable for authorization purposes, as they are
+ subject to races.</para>
</refsect1>
<refsect1>
code.</para>
</refsect1>
+ <refsect1>
+ <title>Errors</title>
+
+ <para>Returned errors may indicate the following problems:</para>
+
+ <variablelist>
+
+ <varlistentry>
+ <term><constant>-ESRCH</constant></term>
+
+ <listitem><para>The specified PID does not refer to a running
+ process.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><constant>-BADF</constant></term>
+
+ <listitem><para>The specified socket file descriptor was
+ invalid.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><constant>-ENODATA</constant></term>
+
+ <listitem><para>The given field is not specified for the described
+ process or peer.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><constant>-EINVAL</constant></term>
+
+ <listitem><para>An input parameter was invalid (out of range,
+ or NULL, where that is not accepted).</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><constant>-ENOMEM</constant></term>
+
+ <listitem><para>Memory allocation failed.</para></listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
<refsect1>
<title>Notes</title>
<function>sd_pid_get_owner_uid()</function>,
<function>sd_pid_get_machine_name()</function>,
<function>sd_pid_get_slice()</function>,
+ <function>sd_pid_get_user_slice()</function>,
<function>sd_peer_get_session()</function>,
<function>sd_peer_get_unit()</function>,
<function>sd_peer_get_user_unit()</function>,
<function>sd_peer_get_owner_uid()</function>,
- <function>sd_peer_get_machine_name()</function> and
- <function>sd_peer_get_slice()</function> interfaces are
- available as a shared library, which can be compiled
- and linked to with the
- <constant>libsystemd</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+ <function>sd_peer_get_machine_name()</function>,
+ <function>sd_peer_get_slice()</function> and
+ <function>sd_peer_get_user_slice()</function> interfaces are
+ available as a shared library, which can be compiled and linked to
+ with the <constant>libelogind</constant> <citerefentry
+ project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
file.</para>
<para>Note that the login session identifier as
~ianmdlvl / elogind.git / blobdiff