lsb-base for Debian
-------------------

The Debian lsb-base package provides a series of logging functions to
permit simplified logging of init script actions.  These functions are
specific to Debian and (in some cases) other derived distributions.

  - log_daemon_msg "Starting/stopping long daemon name" "daemond"

    Log starting/stopping of daemons. On Debian, outputs:

    "Starting/stopping long daemon name: daemond"

    and leaves the cursor at the end of the line. If "Fancy output" is
    enabled, outputs:

    "[....] Starting/stopping long daemon name: daemond"

    and leaves the cursor at the end of the line.

  - log_progress_msg "daemon2d"

    Log startup of a second daemon (e.g. sysklogd, nfs init scripts).
    On Debian, outputs " daemon2d" and leaves the cursor at the EOL.

  - log_end_msg 0/1

    Log successful startup.  On Debian, outputs "." followed by newline.
    A non-zero code may also be specified, which indicates failure;
    currently implemented as outputting "failed!" (in red on a color
    TTY) followed by newline.

    Unsucessful startup will cause the specified failure code to be
    returned by this function; unless trapped, this may end your init
    script depending on whether or not set -e is used.

    If "Fancy output" is enabled, it will store the cursor position,
    move it to the start of the line, write a colored "[ ok ]", "[FAIL]"
    or "[warn]" and restore the cursor position. This has the effect of
    updating the "[....]" printed by log_daemon_msg.

  - log_action_msg "Setting VARIABLE to VALUE"

    Log an atomic action by your init script.  Typically, this is the
    setting of a kernel variable, but it might be something else that is
    not expected to take any time (or fail).

    On Debian, a trailing period will be added to the message, followed by
    a newline. If "Fancy output" is enabled, the message will get prepended
    with a blue [info].

  - log_action_begin_msg "Configuring network interfaces"

    Log the start of an action that is expected to take some time.  On
    Debian, an elipsis (...) will follow the message, and the cursor will
    stay at EOL.

    If "Fancy output" is enabled, it will get the same [....] block as
    log_daemon_msg.

  - log_action_cont_msg "flushing ARP cache"

    Log an action as part of a process started by log_action_start_msg().
    On Debian, this message will receive a trailing elipsis, and the cursor
    will stay at EOL.

  - log_action_end_msg {0|1} ["message"]

    Log the end of the action started by log_action_start_msg().  If one
    argument is supplied, either "done." (0) or "failed." (1) will be output,
    followed by a newline.  If a second argument is supplied, the message
    will appear as follows:

    "done (your message here)." --- if first argument is 0
    "failed (your message here)." --- if first argument is 1

    This argument must be quoted, or otherwise only the first word will
    be output.

    On color TTYs, the failure messages will be red.

    Note that unlike log_end_msg(), this function does not return the
    first argument as its exit code.

  - status_of_proc [-p pidfile] pathname "Daemon_name"

    Log the status of a process and return an LSB-compliant exit status
    code:

    0       program is running or service is OK
    1       program is dead and /var/run pid file exists
    2       program is dead and /var/lock lock file exists
    3       program is not running
    4       program or service status is unknown
    5-99    reserved for future LSB use
    100-149 reserved for distribution use
    150-199 reserved for application use
    200-254 reserved

    On Debian, outputs:
      "Daemon_name is running.".
      "Daemon_name is not running ... failed!"

    The pidfile path will be used as argument for pidofproc and must be
    provided if the pidfile is not /var/run/$daemon_basename.pid.

    status_of_proc can be used to easily implement the "status" argument
    of init scripts:

      status)
        status_of_proc "$DAEMON" "$NAME" && exit 0 || exit $?
      ;;

  - init_is_upstart

    If the currently running init daemon is upstart, return zero; if the
    calling init script belongs to a package which also provides a native
    upstart job, it should generally exit non-zero in this case.

    init_is_upstart is available since lsb-base 4.1+Debian3.

To use these functions, source /lib/lsb/init-functions at the
beginning of your (Bourne sh or compatible) init script.

Please depend on lsb-base to ensure all of these functions are available
for your init scripts.

LSB LOGGING FUNCTIONS

This package also includes the LSB-specified logging functions:

log_success_msg message
log_failure_msg message
log_warning_msg message

These functions *do not* comply with Debian policy and should only be used
by LSB packages.

OTHER LSB FUNCTIONALITY

start_daemon [-f] [-n nicelevel] [-p pidfile] pathname [args...]
  Start "pathname" as a daemon.  We call Debian's start-stop-daemon to
  implement this functionality.

killproc [-p pidfile] pathname [signal]
  Stops "pathname" (using "pidfile", if specified, to find the process
  ID).  This is implemented using start-stop-daemon as well.

pidofproc [-p pidfile] pathname
  Find the process ID of pathname.  If the pidfile is specified, we use the
  first space-delimited word; otherwise, /bin/pidof is used from the
  sysvinit package, if available.

For full documentation, please refer to:

http://refspecs.linuxbase.org/LSB_4.1.0/LSB-Core-generic/LSB-Core-generic/iniscrptfunc.html

Note: Debian packages probably should use start-stop-daemon directly;
however, these functions may be useful in porting init scripts from
other distributions.  Also, if you are developing software for wider
use, you should not expect these functions to be implemented
identically on other LSB-conforming distributions; the only guaranteed
behaviors are those in the specification above.

CUSTOMIZING LOGGING OUTPUT

  - FOR PACKAGES AND DISTRIBUTIONS

Since lsb-base 4.1+Debian4, init-functions will source all
correctly-named files under /lib/lsb/init-functions.d for the purpose of
allowing packages to alter or enhance the init-functions functions.

By providing a file in there, any package or derivative distribution can
override the default behaviour of /lib/lsb/init-functions: logging init
script events, changing the logging messages format, etc.

If supplied, these script fragments shall be compatible with any Debian
/bin/sh, as init scripts sourcing /lib/lsb/init-functions may be running
under any Bourne-style shell permitted by Debian policy (i.e. not just
bash).

  - FOR ADMINISTRATORS

After those distribution-provided files, if it exists,
/etc/lsb-base-logging.sh will be sourced by /lib/lsb/init-functions.
This file is to be supplied by the administrator for machine-specific
overrides. This file may also be useful on systems where the console log
is not visible during startup.

If supplied, this script fragment should be compatible with any Debian
/bin/sh, as init scripts sourcing this file may be running under any
Bourne-style shell permitted by Debian policy (i.e. not just bash).

  - FANCY OUTPUT

"Fancy output" can be overridden by setting FANCYTTY=0 in
/etc/lsb-base-logging.sh .

  - OUTPUT FUNCTIONS

From lsb-base 3.2-14, you can use the following hook functions which
are called by the appropriate functions, instead of supplying your own
logging functions:

log_daemon_msg_pre
log_daemon_msg_post
log_begin_msg_pre (since 4.1+Debian1)
log_begin_msg_post (since 4.1+Debian1)
log_action_msg_pre (since 4.1+Debian1)
log_action_msg_post (since 4.1+Debian1)
log_action_begin_msg_pre (since 4.1+Debian1)
log_action_begin_msg_post (since 4.1+Debian1)
log_end_msg_pre
log_end_msg_post
log_action_end_msg_pre
log_action_end_msg_post

Each function receives all of the arguments sent to the parent
function; the "pre" functions operate before any output, while the
"post" functions operate after the output is produced.

FANCY OUTPUT, KNOWN BUGS

  * Daemons writing too much information on the screen (hence getting
    their output spawned on multiple lines) won't get their [....]
    replaced by [ ok ] as the replacement will happen on the last input
    line.
  * The above has the side-effect of hiding 7 characters of potentially
    useful output.
  * init.d scripts not using the /lib/lsb/init-functions provided
    functions will (obviously) not get the fancy output.

 -- Chris Lawrence <lawrencc@debian.org>, Sat, 18 Sep 2010 17:09:57 -0500
 -- Didier Raboud <odyx@debian.org>  Mon, 21 May 2012 15:00:10 +0200