333 lines
14 KiB
XML
333 lines
14 KiB
XML
<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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<!--
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This file is part of systemd.
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Copyright 2014 Zbigniew Jędrzejewski-Szmek
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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-->
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<refentry id="sd_bus_creds_new_from_pid">
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<refentryinfo>
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<title>sd_bus_creds_new_from_pid</title>
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<productname>systemd</productname>
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<authorgroup>
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<author>
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<contrib>A monkey with a typewriter</contrib>
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<firstname>Zbigniew</firstname>
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<surname>Jędrzejewski-Szmek</surname>
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<email>zbyszek@in.waw.pl</email>
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</author>
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</authorgroup>
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</refentryinfo>
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<refmeta>
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<refentrytitle>sd_bus_creds_new_from_pid</refentrytitle>
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<manvolnum>3</manvolnum>
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</refmeta>
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<refnamediv>
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<refname>sd_bus_creds_new_from_pid</refname>
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<refname>sd_bus_creds_get_mask</refname>
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<refname>sd_bus_creds_get_augmented_mask</refname>
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<refname>sd_bus_creds_ref</refname>
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<refname>sd_bus_creds_unref</refname>
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<refpurpose>Retrieve credentials object for the specified PID</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<funcsynopsis>
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<funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo>
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<funcprototype>
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<funcdef>int <function>sd_bus_creds_new_from_pid</function></funcdef>
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<paramdef>pid_t <parameter>pid</parameter></paramdef>
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<paramdef>uint64_t <parameter>creds_mask</parameter></paramdef>
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<paramdef>sd_bus_creds **<parameter>ret</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>uint64_t <function>sd_bus_creds_get_mask</function></funcdef>
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<paramdef>const sd_bus_creds *<parameter>c</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>uint64_t <function>sd_bus_creds_get_augmented_mask</function></funcdef>
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<paramdef>const sd_bus_creds *<parameter>c</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>sd_bus_creds *<function>sd_bus_creds_ref</function></funcdef>
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<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>sd_bus_creds *<function>sd_bus_creds_unref</function></funcdef>
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<paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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<para>
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<constant>SD_BUS_CREDS_PID</constant>,
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<constant>SD_BUS_CREDS_PPID</constant>,
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<constant>SD_BUS_CREDS_TID</constant>,
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<constant>SD_BUS_CREDS_UID</constant>,
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<constant>SD_BUS_CREDS_EUID</constant>,
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<constant>SD_BUS_CREDS_SUID</constant>,
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<constant>SD_BUS_CREDS_FSUID</constant>,
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<constant>SD_BUS_CREDS_GID</constant>,
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<constant>SD_BUS_CREDS_EGID</constant>,
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<constant>SD_BUS_CREDS_SGID</constant>,
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<constant>SD_BUS_CREDS_FSGID</constant>,
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<constant>SD_BUS_CREDS_SUPPLEMENTARY_GIDS</constant>,
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<constant>SD_BUS_CREDS_COMM</constant>,
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<constant>SD_BUS_CREDS_TID_COMM</constant>,
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<constant>SD_BUS_CREDS_EXE</constant>,
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<constant>SD_BUS_CREDS_CMDLINE</constant>,
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<constant>SD_BUS_CREDS_CGROUP</constant>,
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<constant>SD_BUS_CREDS_UNIT</constant>,
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<constant>SD_BUS_CREDS_SLICE</constant>,
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<constant>SD_BUS_CREDS_USER_UNIT</constant>,
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<constant>SD_BUS_CREDS_USER_SLICE</constant>,
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<constant>SD_BUS_CREDS_SESSION</constant>,
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<constant>SD_BUS_CREDS_OWNER_UID</constant>,
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<constant>SD_BUS_CREDS_EFFECTIVE_CAPS</constant>,
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<constant>SD_BUS_CREDS_PERMITTED_CAPS</constant>,
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<constant>SD_BUS_CREDS_INHERITABLE_CAPS</constant>,
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<constant>SD_BUS_CREDS_BOUNDING_CAPS</constant>,
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<constant>SD_BUS_CREDS_SELINUX_CONTEXT</constant>,
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<constant>SD_BUS_CREDS_AUDIT_SESSION_ID</constant>,
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<constant>SD_BUS_CREDS_AUDIT_LOGIN_UID</constant>,
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<constant>SD_BUS_CREDS_TTY</constant>,
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<constant>SD_BUS_CREDS_UNIQUE_NAME</constant>,
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<constant>SD_BUS_CREDS_WELL_KNOWN_NAMES</constant>,
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<constant>SD_BUS_CREDS_DESCRIPTION</constant>,
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<constant>SD_BUS_CREDS_AUGMENT</constant>,
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<constant>_SD_BUS_CREDS_ALL</constant>
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</para>
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</refsynopsisdiv>
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<refsect1>
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<title>Description</title>
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<para><function>sd_bus_creds_new_from_pid()</function> creates a
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new credentials object and fills it with information about the
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process <parameter>pid</parameter>. The pointer to this object
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will be stored in the <parameter>ret</parameter> pointer. Note that
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credential objects may also be created and retrieved via
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<citerefentry><refentrytitle>sd_bus_get_name_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_bus_get_owner_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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and
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<citerefentry><refentrytitle>sd_bus_message_get_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
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<para>The information that will be stored is determined by
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<parameter>creds_mask</parameter>. It may contain a subset of ORed
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constants <constant>SD_BUS_CREDS_PID</constant>,
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<constant>SD_BUS_CREDS_PPID</constant>,
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<constant>SD_BUS_CREDS_TID</constant>,
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<constant>SD_BUS_CREDS_UID</constant>,
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<constant>SD_BUS_CREDS_EUID</constant>,
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<constant>SD_BUS_CREDS_SUID</constant>,
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<constant>SD_BUS_CREDS_FSUID</constant>,
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<constant>SD_BUS_CREDS_GID</constant>,
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<constant>SD_BUS_CREDS_EGID</constant>,
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<constant>SD_BUS_CREDS_SGID</constant>,
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<constant>SD_BUS_CREDS_FSGID</constant>,
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<constant>SD_BUS_CREDS_SUPPLEMENTARY_GIDS</constant>,
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<constant>SD_BUS_CREDS_COMM</constant>,
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<constant>SD_BUS_CREDS_TID_COMM</constant>,
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<constant>SD_BUS_CREDS_EXE</constant>,
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<constant>SD_BUS_CREDS_CMDLINE</constant>,
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<constant>SD_BUS_CREDS_CGROUP</constant>,
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<constant>SD_BUS_CREDS_UNIT</constant>,
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<constant>SD_BUS_CREDS_SLICE</constant>,
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<constant>SD_BUS_CREDS_USER_UNIT</constant>,
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<constant>SD_BUS_CREDS_USER_SLICE</constant>,
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<constant>SD_BUS_CREDS_SESSION</constant>,
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<constant>SD_BUS_CREDS_OWNER_UID</constant>,
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<constant>SD_BUS_CREDS_EFFECTIVE_CAPS</constant>,
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<constant>SD_BUS_CREDS_PERMITTED_CAPS</constant>,
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<constant>SD_BUS_CREDS_INHERITABLE_CAPS</constant>,
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<constant>SD_BUS_CREDS_BOUNDING_CAPS</constant>,
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<constant>SD_BUS_CREDS_SELINUX_CONTEXT</constant>,
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<constant>SD_BUS_CREDS_AUDIT_SESSION_ID</constant>,
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<constant>SD_BUS_CREDS_AUDIT_LOGIN_UID</constant>,
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<constant>SD_BUS_CREDS_TTY</constant>,
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<constant>SD_BUS_CREDS_UNIQUE_NAME</constant>,
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<constant>SD_BUS_CREDS_WELL_KNOWN_NAMES</constant>, and
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<constant>SD_BUS_CREDS_DESCRIPTION</constant>. Use the special
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value <constant>_SD_BUS_CREDS_ALL</constant> to request all
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supported fields. The <constant>SD_BUS_CREDS_AUGMENT</constant>
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constant may not be ORed into the mask for invocations of
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<function>sd_bus_creds_new_from_pid()</function>.</para>
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<para>Fields can be retrieved from the credentials object using
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<citerefentry><refentrytitle>sd_bus_creds_get_pid</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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and other functions which correspond directly to the constants
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listed above.</para>
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<para>A mask of fields which were actually successfully retrieved
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can be retrieved with
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<function>sd_bus_creds_get_mask()</function>. If the credentials
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object was created with
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<function>sd_bus_creds_new_from_pid()</function>, this will be a
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subset of fields requested in <parameter>creds_mask</parameter>.
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</para>
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<para>Similar to <function>sd_bus_creds_get_mask()</function>, the
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function <function>sd_bus_creds_get_augmented_mask()</function>
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returns a bitmask of field constants. The mask indicates which
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credential fields have been retrieved in a non-atomic fashion. For
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credential objects created via
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<function>sd_bus_creds_new_from_pid()</function>, this mask will be
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identical to the mask returned by
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<function>sd_bus_creds_get_mask()</function>. However, for
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credential objects retrieved via
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<function>sd_bus_get_name_creds()</function>, this mask will be set
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for the credential fields that could not be determined atomically
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at peer connection time, and which were later added by reading
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augmenting credential data from
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<filename>/proc</filename>. Similarly, for credential objects
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retrieved via <function>sd_bus_get_owner_creds()</function>, the
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mask is set for the fields that could not be determined atomically
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at bus creation time, but have been augmented. Similarly, for
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credential objects retrieved via
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<function>sd_bus_message_get_creds()</function>, the mask is set
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for the fields that could not be determined atomically at message
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sending time, but have been augmented. The mask returned by
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<function>sd_bus_creds_get_augmented_mask()</function> is always a
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subset of (or identical to) the mask returned by
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<function>sd_bus_creds_get_mask()</function> for the same
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object. The latter call hence returns all credential fields
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available in the credential object, the former then marks the
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subset of those that have been augmented. Note that augmented
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fields are unsuitable for authorization decisions, as they may be
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retrieved at different times, thus being subject to races. Hence,
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augmented fields should be used exclusively for informational
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purposes.
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</para>
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<para><function>sd_bus_creds_ref()</function> creates a new
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reference to the credentials object <parameter>c</parameter>. This
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object will not be destroyed until
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<function>sd_bus_creds_unref()</function> has been called as many
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times plus once more. Once the reference count has dropped to zero,
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<parameter>c</parameter> cannot be used anymore, so further
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calls to <function>sd_bus_creds_ref(c)</function> or
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<function>sd_bus_creds_unref(c)</function> are illegal.</para>
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<para><function>sd_bus_creds_unref()</function> destroys a reference
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to <parameter>c</parameter>.</para>
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</refsect1>
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<refsect1>
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<title>Return Value</title>
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<para>On success, <function>sd_bus_creds_new_from_pid()</function>
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returns 0 or a positive integer. On failure, it returns a negative
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errno-style error code.</para>
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<para><function>sd_bus_creds_get_mask()</function> returns the
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mask of successfully acquired fields.</para>
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<para><function>sd_bus_creds_get_augmented_mask()</function>
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returns the mask of fields that have been augmented from data in
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<filename>/proc</filename>, and are thus not suitable for
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authorization decisions.</para>
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<para><function>sd_bus_creds_ref()</function> always returns the
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argument.</para>
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<para><function>sd_bus_creds_unref()</function> always returns
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<constant>NULL</constant>.</para>
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</refsect1>
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<refsect1>
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<title>Reference ownership</title>
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<para>Function <function>sd_bus_creds_new_from_pid()</function>
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creates a new object and the caller owns the sole reference. When
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not needed anymore, this reference should be destroyed with
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<citerefentry><refentrytitle>sd_bus_creds_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
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</para>
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</refsect1>
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<refsect1>
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<title>Errors</title>
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<para>Returned errors may indicate the following problems:</para>
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<variablelist>
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<varlistentry>
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<term><constant>-ESRCH</constant></term>
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<listitem><para>Specified <parameter>pid</parameter> could not
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be found.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>-EINVAL</constant></term>
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<listitem><para>Specified parameter is invalid
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(<constant>NULL</constant> in case of output
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parameters).</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>-ENOMEM</constant></term>
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<listitem><para>Memory allocation failed.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>-EOPNOTSUPP</constant></term>
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<listitem><para>One of the requested fields is unknown to the local system.</para></listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1>
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<title>Notes</title>
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<para><function>sd_bus_creds_new_from_pid()</function> and the
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other calls described here are available as a shared library,
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which can be compiled and linked to with the
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<constant>libsystemd</constant> <citerefentry
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project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
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file.</para>
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</refsect1>
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<refsect1>
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<title>See Also</title>
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<para>
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<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_bus_creds_get_pid</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_bus_get_name_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_bus_get_owner_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_bus_message_get_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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</para>
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</refsect1>
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</refentry>
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