man/sd_pid_get_session.xml

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  11   Copyright 2010 Lennart Poettering
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  26
  27 <refentry id="sd_pid_get_session" conditional='HAVE_PAM'>
  28
  29   <refentryinfo>
  30     <title>sd_pid_get_session</title>
  31     <productname>systemd</productname>
  32
  33     <authorgroup>
  34       <author>
  35         <contrib>Developer</contrib>
  36         <firstname>Lennart</firstname>
  37         <surname>Poettering</surname>
  38         <email>lennart@poettering.net</email>
  39       </author>
  40     </authorgroup>
  41   </refentryinfo>
  42
  43   <refmeta>
  44     <refentrytitle>sd_pid_get_session</refentrytitle>
  45     <manvolnum>3</manvolnum>
  46   </refmeta>
  47
  48   <refnamediv>
  49     <refname>sd_pid_get_session</refname>
  50     <refname>sd_pid_get_unit</refname>
  51     <refname>sd_pid_get_user_unit</refname>
  52     <refname>sd_pid_get_owner_uid</refname>
  53     <refname>sd_pid_get_machine_name</refname>
  54     <refname>sd_pid_get_slice</refname>
  55     <refname>sd_peer_get_session</refname>
  56     <refname>sd_peer_get_unit</refname>
  57     <refname>sd_peer_get_user_unit</refname>
  58     <refname>sd_peer_get_owner_uid</refname>
  59     <refname>sd_peer_get_machine_name</refname>
  60     <refname>sd_peer_get_slice</refname>
  61     <refpurpose>Determine session, service, owner of a
  62     session, container/VM or slice of a specific
  63     PID or socket peer</refpurpose>
  64   </refnamediv>
  65
  66   <refsynopsisdiv>
  67     <funcsynopsis>
  68       <funcsynopsisinfo>#include &lt;systemd/sd-login.h&gt;</funcsynopsisinfo>
  69
  70       <funcprototype>
  71         <funcdef>int <function>sd_pid_get_session</function></funcdef>
  72         <paramdef>pid_t <parameter>pid</parameter></paramdef>
  73         <paramdef>char **<parameter>session</parameter></paramdef>
  74       </funcprototype>
  75
  76       <funcprototype>
  77         <funcdef>int <function>sd_pid_get_unit</function></funcdef>
  78         <paramdef>pid_t <parameter>pid</parameter></paramdef>
  79         <paramdef>char **<parameter>unit</parameter></paramdef>
  80       </funcprototype>
  81
  82       <funcprototype>
  83         <funcdef>int <function>sd_pid_get_user_unit</function></funcdef>
  84         <paramdef>pid_t <parameter>pid</parameter></paramdef>
  85         <paramdef>char **<parameter>unit</parameter></paramdef>
  86       </funcprototype>
  87
  88       <funcprototype>
  89         <funcdef>int <function>sd_pid_get_owner_uid</function></funcdef>
  90         <paramdef>pid_t <parameter>pid</parameter></paramdef>
  91         <paramdef>uid_t *<parameter>uid</parameter></paramdef>
  92       </funcprototype>
  93
  94       <funcprototype>
  95         <funcdef>int <function>sd_pid_get_machine_name</function></funcdef>
  96         <paramdef>pid_t <parameter>pid</parameter></paramdef>
  97         <paramdef>char **<parameter>name</parameter></paramdef>
  98       </funcprototype>
  99
 100       <funcprototype>
 101         <funcdef>int <function>sd_pid_get_slice</function></funcdef>
 102         <paramdef>pid_t <parameter>pid</parameter></paramdef>
 103         <paramdef>char **<parameter>slice</parameter></paramdef>
 104       </funcprototype>
 105
 106       <funcprototype>
 107         <funcdef>int <function>sd_peer_get_session</function></funcdef>
 108         <paramdef>int <parameter>fd</parameter></paramdef>
 109         <paramdef>char **<parameter>session</parameter></paramdef>
 110       </funcprototype>
 111
 112       <funcprototype>
 113         <funcdef>int <function>sd_peer_get_unit</function></funcdef>
 114         <paramdef>int <parameter>fd</parameter></paramdef>
 115         <paramdef>char **<parameter>unit</parameter></paramdef>
 116       </funcprototype>
 117
 118       <funcprototype>
 119         <funcdef>int <function>sd_peer_get_user_unit</function></funcdef>
 120         <paramdef>int <parameter>fd</parameter></paramdef>
 121         <paramdef>char **<parameter>unit</parameter></paramdef>
 122       </funcprototype>
 123
 124       <funcprototype>
 125         <funcdef>int <function>sd_peer_get_owner_uid</function></funcdef>
 126         <paramdef>int <parameter>fd</parameter></paramdef>
 127         <paramdef>uid_t *<parameter>uid</parameter></paramdef>
 128       </funcprototype>
 129
 130       <funcprototype>
 131         <funcdef>int <function>sd_peer_get_machine_name</function></funcdef>
 132         <paramdef>int <parameter>fd</parameter></paramdef>
 133         <paramdef>char **<parameter>name</parameter></paramdef>
 134       </funcprototype>
 135
 136       <funcprototype>
 137         <funcdef>int <function>sd_peer_get_slice</function></funcdef>
 138         <paramdef>int <parameter>fd</parameter></paramdef>
 139         <paramdef>char **<parameter>slice</parameter></paramdef>
 140       </funcprototype>
 141     </funcsynopsis>
 142   </refsynopsisdiv>
 143
 144   <refsect1>
 145     <title>Description</title>
 146
 147     <para><function>sd_pid_get_session()</function> may be used to
 148     determine the login session identifier of a process identified by
 149     the specified process identifier. The session identifier is a
 150     short string, suitable for usage in file system paths. Note that
 151     not all processes are part of a login session (e.g. system service
 152     processes, user processes that are shared between multiple
 153     sessions of the same user, or kernel threads). For processes not
 154     being part of a login session this function will fail with
 155     -ENXIO. The returned string needs to be freed with the libc
 156     <citerefentry
 157     project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 158     call after use.</para>
 159
 160     <para><function>sd_pid_get_unit()</function> may be used to
 161     determine the systemd system unit (i.e. system service) identifier
 162     of a process identified by the specified PID. The unit name is a
 163     short string, suitable for usage in file system paths. Note that
 164     not all processes are part of a system unit/service (e.g. user
 165     processes, or kernel threads). For processes not being part of a
 166     systemd system unit this function will fail with -ENXIO (More
 167     specifically: this call will not work for processes that are part
 168     of user units, use <function>sd_pid_get_user_unit()</function> for
 169     that.) The returned string needs to be freed with the libc
 170     <citerefentry
 171     project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 172     call after use.</para>
 173
 174     <para><function>sd_pid_get_user_unit()</function> may be used to
 175     determine the systemd user unit (i.e. user service) identifier of
 176     a process identified by the specified PID. This is similar to
 177     <function>sd_pid_get_unit()</function> but applies to user units
 178     instead of system units.</para>
 179
 180     <para><function>sd_pid_get_owner_uid()</function> may be used to
 181     determine the Unix user identifier of the owner of the session of
 182     a process identified the specified PID. Note that this function
 183     will succeed for user processes which are shared between multiple
 184     login sessions of the same user, where
 185     <function>sd_pid_get_session()</function> will fail. For processes
 186     not being part of a login session and not being a shared process
 187     of a user this function will fail with -ENXIO.</para>
 188
 189     <para><function>sd_pid_get_machine_name()</function> may be used
 190     to determine the name of the VM or container is a member of. The
 191     machine name is a short string, suitable for usage in file system
 192     paths. The returned string needs to be freed with the libc
 193     <citerefentry
 194     project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 195     call after use. For processes not part of a VM or containers this
 196     function fails with -ENXIO.</para>
 197
 198     <para><function>sd_pid_get_slice()</function> may be used to
 199     determine the slice unit the process is a member of. See
 200     <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 201     for details about slices. The returned string needs to be freed
 202     with the libc
 203     <citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 204     call after use.</para>
 205
 206     <para>If the <varname>pid</varname> parameter of any of these
 207     functions is passed as 0, the operation is executed for the
 208     calling process.</para>
 209
 210     <para>The <function>sd_peer_get_session()</function>,
 211     <function>sd_peer_get_unit()</function>,
 212     <function>sd_peer_get_user_unit()</function>,
 213     <function>sd_peer_get_owner_uid()</function>,
 214     <function>sd_peer_get_machine_name()</function> and
 215     <function>sd_peer_get_slice()</function> calls operate similar to
 216     their PID counterparts, but operate on a connected AF_UNIX socket
 217     and retrieve information about the connected peer process.</para>
 218   </refsect1>
 219
 220   <refsect1>
 221     <title>Return Value</title>
 222
 223     <para>On success, these calls return 0 or a positive integer. On
 224     failure, these calls return a negative errno-style error
 225     code.</para>
 226   </refsect1>
 227
 228   <refsect1>
 229     <title>Errors</title>
 230
 231     <para>Returned errors may indicate the following problems:</para>
 232
 233     <variablelist>
 234
 235       <varlistentry>
 236         <term><constant>-ENXIO</constant></term>
 237
 238         <listitem><para>Given field is not specified for the described
 239         process or peer.</para>
 240         </listitem>
 241       </varlistentry>
 242
 243       <varlistentry>
 244         <term><constant>-ESRCH</constant></term>
 245
 246         <listitem><para>The specified PID does not refer to a running
 247         process.</para>
 248         </listitem>
 249       </varlistentry>
 250
 251       <varlistentry>
 252         <term><constant>-ENOMEM</constant></term>
 253
 254         <listitem><para>Memory allocation failed.</para></listitem>
 255       </varlistentry>
 256     </variablelist>
 257   </refsect1>
 258
 259   <refsect1>
 260     <title>Notes</title>
 261
 262     <para>The <function>sd_pid_get_session()</function>,
 263     <function>sd_pid_get_unit()</function>,
 264     <function>sd_pid_get_user_unit()</function>,
 265     <function>sd_pid_get_owner_uid()</function>,
 266     <function>sd_pid_get_machine_name()</function>,
 267     <function>sd_pid_get_slice()</function>,
 268     <function>sd_peer_get_session()</function>,
 269     <function>sd_peer_get_unit()</function>,
 270     <function>sd_peer_get_user_unit()</function>,
 271     <function>sd_peer_get_owner_uid()</function>,
 272     <function>sd_peer_get_machine_name()</function> and
 273     <function>sd_peer_get_slice()</function> interfaces are
 274     available as a shared library, which can be compiled
 275     and linked to with the
 276     <constant>libsystemd</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 277     file.</para>
 278
 279     <para>Note that the login session identifier as
 280     returned by <function>sd_pid_get_session()</function>
 281     is completely unrelated to the process session
 282     identifier as returned by
 283     <citerefentry><refentrytitle>getsid</refentrytitle><manvolnum>2</manvolnum></citerefentry>.</para>
 284   </refsect1>
 285
 286   <refsect1>
 287     <title>See Also</title>
 288
 289     <para>
 290       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 291       <citerefentry><refentrytitle>sd-login</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 292       <citerefentry><refentrytitle>sd_session_is_active</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 293       <citerefentry><refentrytitle>getsid</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
 294       <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 295       <citerefentry><refentrytitle>systemd-machined.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 296     </para>
 297   </refsect1>
 298
 299 </refentry>