man/sd_pid_get_session.xml

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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                 <refname>sd_pid_get_machine_name</refname>
  51                 <refname>sd_pid_get_slice</refname>
  52                 <refpurpose>Determine session, service, owner of a
  53                 session, container/VM or slice of a specific
  54                 PID</refpurpose>
  55         </refnamediv>
  56
  57         <refsynopsisdiv>
  58                 <funcsynopsis>
  59                         <funcsynopsisinfo>#include &lt;systemd/sd-login.h&gt;</funcsynopsisinfo>
  60
  61                         <funcprototype>
  62                                 <funcdef>int <function>sd_pid_get_session</function></funcdef>
  63                                 <paramdef>pid_t <parameter>pid</parameter></paramdef>
  64                                 <paramdef>char** <parameter>session</parameter></paramdef>
  65                         </funcprototype>
  66
  67                         <funcprototype>
  68                                 <funcdef>int <function>sd_pid_get_unit</function></funcdef>
  69                                 <paramdef>pid_t <parameter>pid</parameter></paramdef>
  70                                 <paramdef>char** <parameter>unit</parameter></paramdef>
  71                         </funcprototype>
  72
  73                         <funcprototype>
  74                                 <funcdef>int <function>sd_pid_get_user_unit</function></funcdef>
  75                                 <paramdef>pid_t <parameter>pid</parameter></paramdef>
  76                                 <paramdef>char** <parameter>unit</parameter></paramdef>
  77                         </funcprototype>
  78
  79                         <funcprototype>
  80                                 <funcdef>int <function>sd_pid_get_owner_uid</function></funcdef>
  81                                 <paramdef>pid_t <parameter>pid</parameter></paramdef>
  82                                 <paramdef>uid_t* <parameter>uid</parameter></paramdef>
  83                         </funcprototype>
  84
  85                         <funcprototype>
  86                                 <funcdef>int <function>sd_pid_get_machine_name</function></funcdef>
  87                                 <paramdef>pid_t <parameter>pid</parameter></paramdef>
  88                                 <paramdef>char** <parameter>name</parameter></paramdef>
  89                         </funcprototype>
  90
  91                         <funcprototype>
  92                                 <funcdef>int <function>sd_pid_get_slice</function></funcdef>
  93                                 <paramdef>pid_t <parameter>pid</parameter></paramdef>
  94                                 <paramdef>char** <parameter>slice</parameter></paramdef>
  95                         </funcprototype>
  96                 </funcsynopsis>
  97         </refsynopsisdiv>
  98
  99         <refsect1>
 100                 <title>Description</title>
 101
 102                 <para><function>sd_pid_get_session()</function> may be
 103                 used to determine the login session identifier of a
 104                 process identified by the specified process
 105                 identifier. The session identifier is a short string,
 106                 suitable for usage in file system paths. Note that not
 107                 all processes are part of a login session (e.g. system
 108                 service processes, user processes that are shared
 109                 between multiple sessions of the same user, or kernel
 110                 threads). For processes not being part of a login
 111                 session this function will fail. The returned string
 112                 needs to be freed with the libc
 113                 <citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 114                 call after use.</para>
 115
 116                 <para><function>sd_pid_get_unit()</function> may be
 117                 used to determine the systemd system unit (i.e. system
 118                 service) identifier of a process identified by the
 119                 specified PID. The unit name is a short string,
 120                 suitable for usage in file system paths. Note that not
 121                 all processes are part of a system unit/service
 122                 (e.g. user processes, or kernel threads). For
 123                 processes not being part of a systemd system unit this
 124                 function will fail. (More specifically: this call will
 125                 not work for processes that are part of user units,
 126                 use <function>sd_pid_get_user_unit()</function> for
 127                 that.) The returned string needs to be freed with the
 128                 libc
 129                 <citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 130                 call after use.</para>
 131
 132                 <para><function>sd_pid_get_user_unit()</function> may
 133                 be used to determine the systemd user unit (i.e. user
 134                 service) identifier of a process identified by the
 135                 specified PID. This is similar to
 136                 <function>sd_pid_get_unit()</function> but applies to
 137                 user units instead of system units.</para>
 138
 139                 <para><function>sd_pid_get_owner_uid()</function> may
 140                 be used to determine the Unix user identifier of the
 141                 owner of the session of a process identified the
 142                 specified PID. Note that this function will succeed
 143                 for user processes which are shared between multiple
 144                 login sessions of the same user, where
 145                 <function>sd_pid_get_session()</function> will
 146                 fail. For processes not being part of a login session
 147                 and not being a shared process of a user this function
 148                 will fail.</para>
 149
 150                 <para><function>sd_pid_get_machine_name()</function>
 151                 may be used to determine the name of the VM or
 152                 container is a member of. The machine name is a short
 153                 string, suitable for usage in file system paths. The
 154                 returned string needs to be freed with the libc
 155                 <citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 156                 call after use.</para>
 157
 158                 <para><function>sd_pid_get_slice()</function> may be
 159                 used to determine the slice unit the process is a
 160                 member of. See
 161                 <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 162                 for details about slices. The returned string needs to
 163                 be freed with the libc
 164                 <citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 165                 call after use.</para>
 166
 167                 <para>If the <varname>pid</varname> parameter of any
 168                 of these functions is passed as 0 the operation is
 169                 executed for the calling process.</para>
 170         </refsect1>
 171
 172         <refsect1>
 173                 <title>Return Value</title>
 174
 175                 <para>On success these calls return 0 or a positive
 176                 integer. On failure, these calls return a negative
 177                 errno-style error code.</para>
 178         </refsect1>
 179
 180         <refsect1>
 181                 <title>Notes</title>
 182
 183                 <para>The <function>sd_pid_get_session()</function>,
 184                 <function>sd_pid_get_unit()</function>,
 185                 <function>sd_pid_get_user_unit()</function>,
 186                 <function>sd_pid_get_owner_uid()</function>,
 187                 <function>sd_pid_get_machine_name()</function> and
 188                 <function>sd_pid_get_slice()</function> interfaces are
 189                 available as shared library, which can be compiled and
 190                 linked to with the
 191                 <constant>libsystemd-login</constant> <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 192                 file.</para>
 193
 194                 <para>Note that the login session identifier as
 195                 returned by <function>sd_pid_get_session()</function>
 196                 is completely unrelated to the process session
 197                 identifier as returned by
 198                 <citerefentry><refentrytitle>getsid</refentrytitle><manvolnum>2</manvolnum></citerefentry>.</para>
 199         </refsect1>
 200
 201         <refsect1>
 202                 <title>See Also</title>
 203
 204                 <para>
 205                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 206                         <citerefentry><refentrytitle>sd-login</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 207                         <citerefentry><refentrytitle>sd_session_is_active</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 208                         <citerefentry><refentrytitle>getsid</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
 209                         <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 210                 </para>
 211         </refsect1>
 212
 213 </refentry>