Commit ffa16db0 authored by Lennart Poettering's avatar Lennart Poettering
Browse files

man: document special journal fields

parent 3eff4208
......@@ -667,6 +667,7 @@ MANPAGES = \
man/systemd.snapshot.5 \
man/systemd.exec.5 \
man/systemd.special.7 \
man/systemd.journal-fields.7 \
man/daemon.7 \
man/runlevel.8 \
man/telinit.8 \
......
......@@ -68,7 +68,9 @@
<para>If a match argument is passed the output is
filtered accordingly. A match is in the format
<literal>FIELD=VALUE</literal>,
e.g. <literal>_SYSTEMD_UNIT=httpd.service</literal>.</para>
e.g. <literal>_SYSTEMD_UNIT=httpd.service</literal>. See
<citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>
for a list of well-known fields.</para>
<para>Output is interleaved from all accessible
journal files, whether they are rotated or currently
......@@ -253,6 +255,7 @@
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
<citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
</para>
</refsect1>
......
......@@ -247,6 +247,7 @@
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
</para>
</refsect1>
......
<?xml version='1.0'?> <!--*-nxml-*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!--
This file is part of systemd.
Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
-->
<refentry id="systemd.journal-fields">
<refentryinfo>
<title>systemd.journal-fields</title>
<productname>systemd</productname>
<authorgroup>
<author>
<contrib>Developer</contrib>
<firstname>Lennart</firstname>
<surname>Poettering</surname>
<email>lennart@poettering.net</email>
</author>
</authorgroup>
</refentryinfo>
<refmeta>
<refentrytitle>systemd.journal-fields</refentrytitle>
<manvolnum>7</manvolnum>
</refmeta>
<refnamediv>
<refname>systemd.journal-fields</refname>
<refpurpose>Special journal fields</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<para>Entries in the journal resemble an environment
block in their syntax, however with fields that can
include binary data. Primarily, fields are formatted
ASCII strings, and binary formatting is used only
where formatting as ASCII makes little sense. New
fields may be freely defined by applications, but a
few fields have special meaning. All fields with
special meaning are optional.</para>
</refsect1>
<refsect1>
<title>User Journal Fields</title>
<para>User fields are fields that are directly passed
from clients and stored in the journal.</para>
<variablelist>
<varlistentry>
<term>MESSAGE=</term>
<listitem>
<para>The human readable
message string for this
entry. This is supposed to be
the primary text shown to the
user. It is not translated,
and is not supposed to be
parsed for meta data.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>MESSAGE_ID=</term>
<listitem>
<para>A 128bit message
identifier ID for recognizing
certain message types, if this
is desirable. This should
contain a 128bit id formatted
as lower-case hexadecimal
string, without any separating
dashes or suchlike. This is
recommended to be a UUID
compatible ID, but this is not
enforced, and formatted
differently. Developers can
generate a new ID for this
purpose with
<command>journalctl
--new-id</command>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>PRIORITY=</term>
<listitem>
<para>A priority value between
0 (<literal>emerg</literal>)
and 7
(<literal>debug</literal>)
formatted as decimal
string. This field is
compatible with syslog's
priority concept.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>CODE_FILE=</term>
<term>CODE_LINE=</term>
<term>CODE_FUNC=</term>
<listitem>
<para>The code location
generating this message, if
known. Contains the source
file name, the line number and
the function name.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>SYSLOG_FACILITY=</term>
<term>SYSLOG_IDENTIFIER=</term>
<term>SYSLOG_PID=</term>
<listitem>
<para>Syslog compatibility
fields containing the facility
(formatted as decimal string),
the identifier string
(i.e. "tag"), and the client
PID.</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Trusted Journal Fields</title>
<para>Fields prefixed with an underscore are trusted
fields, i.e. fields that are implicitly added by the
journal and cannot be altered by client code.</para>
<variablelist>
<varlistentry>
<term>_PID=</term>
<term>_UID=</term>
<term>_GID=</term>
<listitem>
<para>The process, user and
group ID of the process the
journal entry originates from
formatted as decimal
string.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>_COMM=</term>
<term>_EXE=</term>
<term>_CMDLINE=</term>
<listitem>
<para>The name, the executable
path and the command line of
the process the journal entry
originates from.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>_AUDIT_SESSION=</term>
<term>_AUDIT_LOGINUID=</term>
<listitem>
<para>The session and login
UID of the process the journal
entry originates from, as
maintained by the kernel audit
subsystem.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>_SYSTEMD_CGROUP=</term>
<term>_SYSTEMD_SESSION=</term>
<term>_SYSTEMD_UNIT=</term>
<term>_SYSTEMD_OWNER_UID=</term>
<listitem>
<para>The contol group path in
the systemd hierarchy, the
systemd session ID (if any),
the systemd unit name (if any)
and the owner UID of the
systemd session (if any) of
the process the journal entry
originates from.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>_SELINUX_CONTEXT=</term>
<listitem>
<para>The SELinux security
context of the process the
journal entry originates
from.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>_SOURCE_REALTIME_TIMESTAMP=</term>
<listitem>
<para>The earliest trusted
timestamp of the message, if
any is known that is different
from the reception time of the
journal. The time in usec
since the epoch formatted as
decimal string.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>_BOOT_ID=</term>
<listitem>
<para>The kernel boot ID for
the boot the message was
generated in, formatted as
128bit hexadecimal
string.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>_MACHINE_ID=</term>
<listitem>
<para>The machine ID of the
originating host, as available
in
<citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>_HOSTNAME=</term>
<listitem>
<para>The name of the
originating host.</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Address Fields</title>
<para>During serialization into external formats the
addresses of journal entries are serialized into
fields prefixed with double underscores. Note that
these aren't proper fields when stored in the journal,
but addressing meta data of entries.</para>
<variablelist>
<varlistentry>
<term>__CURSOR=</term>
<listitem>
<para>The cursor for the
entry. A cursor is an opaque
text string that uniquely
describes the position of an
entry in the journal and is
portable across machines,
platforms and journal
files.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>__REALTIME_TIMESTAMP=</term>
<listitem>
<para>The wallclock time
(CLOCK_REALTIME) at the point
in time the entry was received
by the journal. This has
different properties from
<literal>_SOURCE_REALTIME_TIMESTAMP=</literal>
as it is usually a bit later
but more likely to be
monotonic.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>__MONOTONIC_TIMESTAMP=</term>
<listitem>
<para>The monotonic time
(CLOCK_MONOTONIC) at the point
in time the entry was received
by the journal. To be useful
as an address for the entry
this should be combined with
with boot ID in
<literal>_BOOT_ID=</literal>.</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>
......@@ -348,8 +348,8 @@ static int output_export(sd_journal *j, unsigned line, unsigned n_columns, bool
}
printf("__CURSOR=%s\n"
"__REALTIME=%llu\n"
"__MONOTONIC=%llu\n"
"__REALTIME_TIMESTAMP=%llu\n"
"__MONOTONIC_TIMESTAMP=%llu\n"
"__BOOT_ID=%s\n",
cursor,
(unsigned long long) realtime,
......@@ -460,8 +460,8 @@ static int output_json(sd_journal *j, unsigned line, unsigned n_columns, bool sh
printf("{\n"
"\t\"__CURSOR\" : \"%s\",\n"
"\t\"__REALTIME\" : \"%llu\",\n"
"\t\"__MONOTONIC\" : \"%llu\",\n"
"\t\"__REALTIME_TIMESTAMP\" : \"%llu\",\n"
"\t\"__MONOTONIC_TIMESTAMP\" : \"%llu\",\n"
"\t\"__BOOT_ID\" : \"%s\"",
cursor,
(unsigned long long) realtime,
......
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