Hello everyone,
Here's an updated version of the RFC text, as well as a new version of the
initscriptquery reference script. The fragments.sh script is included just
for completeness, and was not modified.
Changelog:
* fixed typos, updated documentation to an assertive tone
* addressed rcS.d issue (I received no comments on this one, BTW)
* handle multiple links per runlevel nicely
* detect and block attempt to run initscriptquery at runlevel 0 or 6
* address pre-depends/depends issue
Another small RFC dealing with administrative policy enforcement on the
start of initscripts will be sent in a few days. Due to the design of
initscriptquery, such policy enforcement could be done without any
additional changes to other packages.
There are no technical issues left for initscriptquery that I know of. It
should be now in its nearly final state.
RFC: Fix for initscripts being run out of their intended runlevel by
package scripts (during package installs and upgrades).
Interface proposal for /usr/sbin/initscriptquery script:
Assumptions:
Debian uses only sysvinit-compatible initscripts, stored in /etc/init.d/
(currently true for debian, file-rc uses the same /etc/init.d/ scripts as
sysvinit does).
The unique identifier for an initscript is the initscript ID required by
the update-rc.d command.
Documented Command Line Interface:
/usr/sbin/initscriptquery [-q] initscript ID
-q : Run initscriptquery in silent mode, errors are NOT reported to stderr
initscript ID: the update-rc.d identifier for the initscript
Future versions to this script MUST be fully backwards compatible.
Documented behaviour of the initscriptquery script:
stdin shall not be used (it is NOT an interactive script)
stdout shall be used only to output usage information.
stderr shall be used to output all error messages.
Exit status codes:
0 - the initscript is allowed to be started
1 - the initscript is NOT allowed be started
2 - initscript ID unknown
3 - initscript ID known, but behaviour is undefined
4 - syntax error
=5 - other error (usually means inconsistency in the underlining
initscript subsystem)
Verbose description of the exit status codes:
0 - the initscript is allowed to be started
sysvinit meaning: There is a non-dangling, executable S?? link in
the rc?.d directory for the given script ID and current runlevel.
Also, no other administrative reasons for not starting the init
scripts exist.
NOTE: If an initscript would be started at the S runlevel, it is
assumed that this should be true for all runlevels that don't
actually stop the initscript as well.
Desired behaviour: Call /etc/init.d/initscript as you'd have done
before the advent of initscriptquery
1 - the initscript is NOT allowed be started
sysvinit meaning: There is a non-dangling, executable K?? link (and
no S?? link) in the rc?.d directory for the given script ID and
current runlevel.
Or, an administrative reason prohibits starting the initscript.
Desired behaviour: Do not run the initscript. If the daemon is
running, assume it's because the user started it manually and would
like it to be left alone (feel free to issue a warning, though).
2 - initscript ID unknown
sysvinit meaning: There isn't a normal file with the name matching
initscript ID in /etc/init.d/ (note that the existence of a
S??initscriptID link/file is NOT enough, as we are constrained to
the same namespace used by update-rc.d).
This might happen if update-rc.d fails, if you forget to run
update-rc.d BEFORE initscriptquery in the package scripts, or if the
user removed the /etc/init.d/ script.
Desired behaviour: Do whatever is appropriate for your package.
Unless -q was given, initscriptquery will have already printed a
warning to stderr. The calling script might want to try to start the
script anyway (which will probably fail, BTW).
3 - initscript ID known, but behaviour is undefined
sysvinit meaning: No S?? or K?? link in the proper rc?.d directory
for the given initscript ID was found, but a /etc/init.d/ file for
the given initscript iD does exist.
Desired behaviour: For non-daemon-starting initscripts, it is
undefined. Do whatever is *safer* for your package (start it anyway,
do nothing, or stop it).
Never start a daemon which isn't already running if you receive this
status code. You can either restart the daemon, stop the daemon, or
do nothing. WARNING: don't use /etc/init.d/initscript restart for
this operation unless the initscript is under your control, and
known not to start a daemon which was not running.
4 - Syntax error
