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org.freedesktop.LogControl1 - D-Bus interface to query and set logging configuration


org.freedesktop.LogControl1 is a generic interface that is intended to be used by any daemon which should allow setting the log level and target over D-Bus. It is implemented by various daemons that are part of the systemd(1) suite.

It is assumed that those settings are global for the whole program, so a fixed object path is used. The interface should always be available under the path /org/freedesktop/LogControl1.


The following interface is exposed:

node /org/freedesktop/LogControl1 {
  interface org.freedesktop.LogControl1 {
      readwrite s LogLevel = '...';
      readwrite s LogTarget = '...';
      readonly s SyslogIdentifier = '...';
  interface org.freedesktop.DBus.Peer { ... };
  interface org.freedesktop.DBus.Introspectable { ... };
  interface org.freedesktop.DBus.Properties { ... };


LogLevel describes the syslog(3)-style log-level, and should be one of "emerg", "alert", "crit", "err", "warning", "notice", "info", "debug", in order of increasing verbosity.

LogTarget describes the log target (mechanism). It should be one of "console" (log to the console or standard output), "kmsg" (log to the kernel ring buffer), "journal" (log to the journal natively, see systemd-journald.service(8)), "syslog" (log using the syslog(3) call).

Those two properties are writable, so they may be set by sufficiently privileged users.

SyslogIdentifier is a read-only property that shows the "syslog identifier". It is a short string that identifies the program that is the source of log messages that is passed to the syslog(3) call.

Note: journalctl option -p/--priority= may be used to filter log messages by log level, option -t/--identifier= may be used to by the syslog identifier, and filters like "_TRANSPORT=syslog", "_TRANSPORT=journal", and "_TRANSPORT=kernel" may be used to filter messages by the mechanism through which they reached systemd-journald.

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