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">
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   8   Copyright 2010 Lennart Poettering
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  23
  24 <refentry id="sd_pid_get_session" conditional='HAVE_PAM'>
  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_user_unit</refname>
  49                 <refname>sd_pid_get_owner_uid</refname>
  50                 <refpurpose>Determine session, service or owner of a session of a specific PID</refpurpose>
  51         </refnamediv>
  52
  53         <refsynopsisdiv>
  54                 <funcsynopsis>
  55                         <funcsynopsisinfo>#include &lt;systemd/sd-login.h&gt;</funcsynopsisinfo>
  56
  57                         <funcprototype>
  58                                 <funcdef>int <function>sd_pid_get_session</function></funcdef>
  59                                 <paramdef>pid_t <parameter>pid</parameter></paramdef>
  60                                 <paramdef>char** <parameter>session</parameter></paramdef>
  61                         </funcprototype>
  62
  63                         <funcprototype>
  64                                 <funcdef>int <function>sd_pid_get_unit</function></funcdef>
  65                                 <paramdef>pid_t <parameter>pid</parameter></paramdef>
  66                                 <paramdef>char** <parameter>unit</parameter></paramdef>
  67                         </funcprototype>
  68
  69                         <funcprototype>
  70                                 <funcdef>int <function>sd_pid_get_user_unit</function></funcdef>
  71                                 <paramdef>pid_t <parameter>pid</parameter></paramdef>
  72                                 <paramdef>char** <parameter>unit</parameter></paramdef>
  73                         </funcprototype>
  74
  75                         <funcprototype>
  76                                 <funcdef>int <function>sd_pid_get_owner_uid</function></funcdef>
  77                                 <paramdef>pid_t <parameter>pid</parameter></paramdef>
  78                                 <paramdef>uid_t* <parameter>uid</parameter></paramdef>
  79                         </funcprototype>
  80                 </funcsynopsis>
  81         </refsynopsisdiv>
  82
  83         <refsect1>
  84                 <title>Description</title>
  85
  86                 <para><function>sd_pid_get_session()</function> may be
  87                 used to determine the login session identifier of a
  88                 process identified by the specified process
  89                 identifier. The session identifier is a short string,
  90                 suitable for usage in file system paths. Note that not
  91                 all processes are part of a login session (e.g. system
  92                 service processes, user processes that are shared
  93                 between multiple sessions of the same user, or kernel
  94                 threads). For processes not being part of a login
  95                 session this function will fail. The returned string
  96                 needs to be freed with the libc
  97                 <citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
  98                 call after use.</para>
  99
 100                 <para><function>sd_pid_get_unit()</function> may be
 101                 used to determine the systemd system unit (i.e. system
 102                 service) identifier of a process identified by the
 103                 specified PID. The unit name is a short string,
 104                 suitable for usage in file system paths. Note that not
 105                 all processes are part of a system unit/service
 106                 (e.g. user processes, or kernel threads). For
 107                 processes not being part of a systemd system unit this
 108                 function will fail. (More specifically: this call will
 109                 not work for processes that are part of user units,
 110                 use <function>sd_pid_get_user_unit()</function> for
 111                 that.)  The returned string needs to be freed with the
 112                 libc
 113                 <citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 114                 call after use.</para>
 115
 116                 <para><function>sd_pid_get_user_unit()</function> may
 117                 be used to determine the systemd user unit (i.e. user
 118                 service) identifier of a process identified by the
 119                 specified PID. This is similar to
 120                 <function>sd_pid_get_unit()</function> but applies to
 121                 user units instead of system units.</para>
 122
 123                 <para><function>sd_pid_get_owner_uid()</function> may
 124                 be used to determine the Unix user identifier of the
 125                 owner of the session of a process identified the
 126                 specified PID. Note that this function will succeed
 127                 for user processes which are shared between multiple
 128                 login sessions of the same user, where
 129                 <function>sd_pid_get_session()</function> will
 130                 fail. For processes not being part of a login session
 131                 and not being a shared process of a user this function
 132                 will fail.</para>
 133
 134                 <para>If the <literal>pid</literal> parameter of any
 135                 of these functions is passed as 0 the operation is
 136                 executed for the calling process.</para>
 137         </refsect1>
 138
 139         <refsect1>
 140                 <title>Return Value</title>
 141
 142                 <para>On success these calls return 0 or a positive
 143                 integer. On failure, these calls return a negative
 144                 errno-style error code.</para>
 145         </refsect1>
 146
 147         <refsect1>
 148                 <title>Notes</title>
 149
 150                 <para>The <function>sd_pid_get_session()</function>,
 151                 <function>sd_pid_get_unit()</function>,
 152                 <function>sd_pid_get_user_unit()</function>, and
 153                 <function>sd_pid_get_owner_uid()</function> interfaces
 154                 are available as shared library, which can be compiled
 155                 and linked to with the
 156                 <literal>libsystemd-login</literal>
 157                 <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 158                 file.</para>
 159
 160                 <para>Note that the login session identifier as
 161                 returned by <function>sd_pid_get_session()</function>
 162                 is completely unrelated to the process session
 163                 identifier as returned by
 164                 <citerefentry><refentrytitle>getsid</refentrytitle><manvolnum>2</manvolnum></citerefentry>.</para>
 165         </refsect1>
 166
 167         <refsect1>
 168                 <title>See Also</title>
 169
 170                 <para>
 171                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 172                         <citerefentry><refentrytitle>sd-login</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 173                         <citerefentry><refentrytitle>sd_session_is_active</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 174                         <citerefentry><refentrytitle>getsid</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 175                 </para>
 176         </refsect1>
 177
 178 </refentry>