man/sd_pid_get_session.xml

   1 <?xml version='1.0'?> <!--*-nxml-*-->
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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   8   Copyright 2010 Lennart Poettering
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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_owner_uid</refname>
  48                 <refpurpose>Determine session or owner of a session of a specific PID</refpurpose>
  49         </refnamediv>
  50
  51         <refsynopsisdiv>
  52                 <funcsynopsis>
  53                         <funcsynopsisinfo>#include &lt;systemd/sd-login.h&gt;</funcsynopsisinfo>
  54
  55                         <funcprototype>
  56                                 <funcdef>int <function>sd_pid_get_session</function></funcdef>
  57                                 <paramdef>pid_t <parameter>pid</parameter></paramdef>
  58                                 <paramdef>char** <parameter>session</parameter></paramdef>
  59                         </funcprototype>
  60
  61                         <funcprototype>
  62                                 <funcdef>int <function>sd_pid_get_owner_uid</function></funcdef>
  63                                 <paramdef>pid_t <parameter>pid</parameter></paramdef>
  64                                 <paramdef>uid_t* <parameter>uid</parameter></paramdef>
  65                         </funcprototype>
  66                 </funcsynopsis>
  67         </refsynopsisdiv>
  68
  69         <refsect1>
  70                 <title>Description</title>
  71
  72                 <para><function>sd_pid_get_session()</function> may be
  73                 used to determine the login session identifier of a
  74                 process identified by the specified process identifier. The session
  75                 identifier is a short string (up to 64 characters),
  76                 consisting only of the characters a-zA-Z0-9 as well as
  77                 '-' and '_'. It is suitable for usage in file system
  78                 paths. Note that not all processes are part of a login
  79                 session (e.g. system service processes and user
  80                 processes that are shared between multiple sessions of
  81                 the same user). For processes not being part of a
  82                 login session this function will fail. The returned
  83                 string needs to be freed with the libc
  84                 <citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
  85                 call after use.</para>
  86
  87                 <para><function>sd_pid_get_owner_uid()</function> may
  88                 be used to determine the Unix user identifier of the
  89                 owner of the session of a process identified the
  90                 specified PID. Note that this function will succeed
  91                 for user processes which are shared between multiple
  92                 login sessions of the same user, where
  93                 <function>sd_pid_get_session()</function> will
  94                 fail. For processes not being part of a login session
  95                 and not being a shared process of a user this function
  96                 will fail.</para>
  97         </refsect1>
  98
  99         <refsect1>
 100                 <title>Return Value</title>
 101
 102                 <para>On success these calls return 0 or a positive
 103                 integer. On failure, these calls return a negative
 104                 errno-style error code.</para>
 105         </refsect1>
 106
 107         <refsect1>
 108                 <title>Notes</title>
 109
 110                 <para>The <function>sd_pid_get_session()</function>
 111                 and <function>sd_pid_get_owner_uid()</function>
 112                 interfaces are available as shared library, which can
 113                 be compiled and linked to with the
 114                 <literal>libsystemd-login</literal>
 115                 <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 116                 file.</para>
 117
 118                 <para>Note that the login session identifier as
 119                 returned by <function>sd_pid_get_session()</function>
 120                 is completely unrelated to the process session
 121                 identifier as returned by
 122                 <citerefentry><refentrytitle>getsid</refentrytitle><manvolnum>2</manvolnum></citerefentry>.</para>
 123         </refsect1>
 124
 125         <refsect1>
 126                 <title>See Also</title>
 127
 128                 <para>
 129                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 130                         <citerefentry><refentrytitle>sd-login</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 131                         <citerefentry><refentrytitle>sd_session_is_active</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 132                         <citerefentry><refentrytitle>getsid</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 133                 </para>
 134         </refsect1>
 135
 136 </refentry>