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[elogind.git] / man / sd_pid_get_session.xml
1 <?xml version='1.0'?> <!--*-nxml-*-->
2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
3         "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
4
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23
24 <refentry id="sd_pid_get_session">
25
26         <refentryinfo>
27                 <title>sd_pid_get_session</title>
28                 <productname>systemd</productname>
29
30                 <authorgroup>
31                         <author>
32                                 <contrib>Developer</contrib>
33                                 <firstname>Lennart</firstname>
34                                 <surname>Poettering</surname>
35                                 <email>lennart@poettering.net</email>
36                         </author>
37                 </authorgroup>
38         </refentryinfo>
39
40         <refmeta>
41                 <refentrytitle>sd_pid_get_session</refentrytitle>
42                 <manvolnum>3</manvolnum>
43         </refmeta>
44
45         <refnamediv>
46                 <refname>sd_pid_get_session</refname>
47                 <refname>sd_pid_get_unit</refname>
48                 <refname>sd_pid_get_owner_uid</refname>
49                 <refpurpose>Determine session, service or owner of a session of a specific PID</refpurpose>
50         </refnamediv>
51
52         <refsynopsisdiv>
53                 <funcsynopsis>
54                         <funcsynopsisinfo>#include &lt;systemd/sd-login.h&gt;</funcsynopsisinfo>
55
56                         <funcprototype>
57                                 <funcdef>int <function>sd_pid_get_session</function></funcdef>
58                                 <paramdef>pid_t <parameter>pid</parameter></paramdef>
59                                 <paramdef>char** <parameter>session</parameter></paramdef>
60                         </funcprototype>
61
62                         <funcprototype>
63                                 <funcdef>int <function>sd_pid_get_unit</function></funcdef>
64                                 <paramdef>pid_t <parameter>pid</parameter></paramdef>
65                                 <paramdef>char** <parameter>unit</parameter></paramdef>
66                         </funcprototype>
67
68                         <funcprototype>
69                                 <funcdef>int <function>sd_pid_get_owner_uid</function></funcdef>
70                                 <paramdef>pid_t <parameter>pid</parameter></paramdef>
71                                 <paramdef>uid_t* <parameter>uid</parameter></paramdef>
72                         </funcprototype>
73                 </funcsynopsis>
74         </refsynopsisdiv>
75
76         <refsect1>
77                 <title>Description</title>
78
79                 <para><function>sd_pid_get_session()</function> may be
80                 used to determine the login session identifier of a
81                 process identified by the specified process
82                 identifier. The session identifier is a short string,
83                 suitable for usage in file system paths. Note that not
84                 all processes are part of a login session (e.g. system
85                 service processes, user processes that are shared
86                 between multiple sessions of the same user, or kernel
87                 threads). For processes not being part of a login
88                 session this function will fail. The returned string
89                 needs to be freed with the libc
90                 <citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
91                 call after use.</para>
92
93                 <para><function>sd_pid_get_unit()</function> may be
94                 used to determine the systemd unit (i.e. system
95                 service) identifier of a process identified by the
96                 specified process identifier. The unit name is a short
97                 string, suitable for usage in file system paths. Note
98                 that not all processes are part of a unit/service
99                 (e.g. user processes, or kernel threads). For
100                 processes not being part of a systemd unit/system
101                 service this function will fail. The returned string
102                 needs to be freed with the libc
103                 <citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
104                 call after use.</para>
105
106                 <para><function>sd_pid_get_owner_uid()</function> may
107                 be used to determine the Unix user identifier of the
108                 owner of the session of a process identified the
109                 specified PID. Note that this function will succeed
110                 for user processes which are shared between multiple
111                 login sessions of the same user, where
112                 <function>sd_pid_get_session()</function> will
113                 fail. For processes not being part of a login session
114                 and not being a shared process of a user this function
115                 will fail.</para>
116         </refsect1>
117
118         <refsect1>
119                 <title>Return Value</title>
120
121                 <para>On success these calls return 0 or a positive
122                 integer. On failure, these calls return a negative
123                 errno-style error code.</para>
124         </refsect1>
125
126         <refsect1>
127                 <title>Notes</title>
128
129                 <para>The <function>sd_pid_get_session()</function>,
130                 <function>sd_pid_get_pid()</function>, and
131                 <function>sd_pid_get_owner_uid()</function> interfaces
132                 are available as shared library, which can be compiled
133                 and linked to with the
134                 <literal>libsystemd-login</literal>
135                 <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
136                 file.</para>
137
138                 <para>Note that the login session identifier as
139                 returned by <function>sd_pid_get_session()</function>
140                 is completely unrelated to the process session
141                 identifier as returned by
142                 <citerefentry><refentrytitle>getsid</refentrytitle><manvolnum>2</manvolnum></citerefentry>.</para>
143         </refsect1>
144
145         <refsect1>
146                 <title>See Also</title>
147
148                 <para>
149                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
150                         <citerefentry><refentrytitle>sd-login</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
151                         <citerefentry><refentrytitle>sd_session_is_active</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
152                         <citerefentry><refentrytitle>getsid</refentrytitle><manvolnum>2</manvolnum></citerefentry>
153                 </para>
154         </refsect1>
155
156 </refentry>