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INVOKE-RC.D(8) Debian GNU/Linux INVOKE-RC.D(8)

NAME

invoke-rc.d - executes System-V style init script actions

SYNOPSIS

invoke-rc.d [--quiet] [--force] [--try-anyway] [--disclose-deny] [--query] [--no-fallback] name action [init script parameters...]

invoke-rc.d [--help]

DESCRIPTION

invoke-rc.d is a generic interface to execute System V style init script /etc/init.d/name actions, obeying runlevel constraints as well as any local policies set by the system administrator.

All access to the init scripts by Debian packages' maintainer scripts should be done through invoke-rc.d.

This manpage documents only the usage and behavior of invoke-rc.d. For a discussion of the System V style init script arrangements please see init(8). More information on invoke-rc.d can be found in the section on runlevels and init.d scripts of the Debian Policy Manual.

INIT SCRIPT ACTIONS

The standard actions are: start, stop, force-stop, restart, try-restart, reload, force-reload, and status. Other actions are accepted, but they can cause problems to policy-rc.d (see the INIT SCRIPT POLICY section), so warnings are generated if the policy layer is active.

Please note that not all init scripts will implement all the actions listed above, and that the policy layer may override an action to another action(s), or even deny it.

Any extra parameters will be passed to the init script(s) being executed.

If an action must be carried out regardless of any local policies, use the --force switch.

OPTIONS

Display usage help.
Quiet mode, no error messages are generated.
Tries to run the init script regardless of policy and init script subsystem errors. Use of this option in Debian maintainer scripts is severely discouraged.
Tries to run the init script if a non-fatal error is detected.
Return status code 101 instead of status code 0 if the init script action is denied by the policy layer.
Returns one of the status codes 100-106. Does not run the init script, and implies --disclose-deny and --no-fallback.
Ignores any fallback action requests by the policy layer. Warning: this is usually a very bad idea for any actions other than start.
Exits before doing anything if a systemd environment is detected and the requested service is a native systemd unit. This is useful for maintainer scripts that want to defer systemd actions to deb-systemd-invoke(1p)

STATUS CODES

Should an init script be executed, invoke-rc.d always returns the status code returned by the init script. Init scripts should not return status codes in the 100+ range (which is reserved in Debian and by the LSB). The status codes returned by invoke-rc.d proper are:

0
Success. Either the init script was run and returned exit status 0 (note that a fallback action may have been run instead of the one given in the command line), or it was not run because of runlevel/local policy constrains and --disclose-deny is not in effect.
1 - 99
Reserved for init.d script, usually indicates a failure.
100
Init script ID (name) unknown. This means the init script was not registered successfully through update-rc.d or that the init script does not exist.
101
Action not allowed. The requested action will not be performed because of runlevel or local policy constraints.
102
Subsystem error. Init script (or policy layer) subsystem malfunction. Also, forced init script execution due to --try-anyway or --force failed.
103
Syntax error.
104
Action allowed. Init script would be run, but --query is in effect.
105
Behavior uncertain. It cannot be determined if action should be carried out or not, and --query is in effect.
106
Fallback action requested. The policy layer denied the requested action, and supplied an allowed fallback action to be used instead.

INIT SCRIPT POLICY

invoke-rc.d introduces the concept of a policy layer which is used to verify if an init script should be run or not, or if something else should be done instead. This layer has various uses, the most immediate ones being avoiding that package upgrades start daemons out-of-runlevel, and that a package starts or stops daemons while inside a chroot jail.

The policy layer has the following abilities: deny or approve the execution of an action; request that another action (called a fallback) is to be taken, instead of the action requested in invoke-rc.d's command line; or request multiple actions to be tried in order, until one of them succeeds (a multiple fallback).

invoke-rc.d itself only pays attention to the current runlevel; it will block any attempts to start a service in a runlevel in which the service is disabled. Other policies are implemented with the use of the policy-rc.d helper, and are only available if /usr/sbin/policy-rc.d is installed in the system.

RUNIT INIT POLICY

When invoke-rc.d is run under runit init, the executable script /etc/runit/override-sysv.d/runit-default is run, if it exists, with name and action as arguments; then the return code is checked. Any value returned other than 104 will deny the action and invoke-rc.d will exit without doing nothing.

The default runit policy (as defined in /etc/runit/override-sysv.d/runit-default) works as follow: if a disabled runit service with the same name is found either in /etc/sv or in /usr/share/runit/sv.current the actions is denied; a runit service is considered disabled if no name or a .name symlink is found in /etc/service directory; if an enabled runit service with the same name is found (a name symlink exists under /etc/service) then if a dh-runit integration is detected the action is denied but if no dh-runit integration is found the action is forwarded to sv(8). If the action is not supported by sv, then the sysvinit script will be called as fallback. If no runit service is found for name then the policy is to run the sysvinit script (continuing with invoke-rc.d).

A service name is considered to have a dh-runit integration if inside the name service directory there is a .meta/bin file, or if a file /usr/share/runit/meta/name/installed is found in the system.

It's possible for the local admin to override the above policy for each single runit service, by touching empty files with appropriate names inside /etc/runit/override-sysv.d/ directory; for details see the README inide the override-sysv.d directory.

The runit policy layer is alway checked after the policy-rc.d layer, so if an action is denied by policy-rc.d the runit layer has no effect.

FILES

/etc/init.d/*
System V init scripts.
/usr/sbin/policy-rc.d
Init script policy layer helper (not required).
/etc/rc?.d/*
System V runlevel configuration.

NOTES

invoke-rc.d special cases the status action, and returns exit status 4 instead of exit status 0 when it is denied.

BUGS

See <http://bugs.debian.org/sysv-rc> and
<http://bugs.debian.org/init-system-helpers> .

SEE ALSO

Debian Policy manual,
/etc/init.d/skeleton,
update-rc.d(8),
init(8),
/usr/share/doc/init-system-helpers/README.policy-rc.d.gz

AUTHOR

Henrique de Moraes Holschuh

License: GNU General Public License v2 or Later (GPLv2+)

COPYRIGHT

2001 Henrique de Moraes Holschuh

1 March 2001