login-utils/initctl.8

   1 .\" Copyright (C) 2000  Richard Gooch
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  17 .\" Richard Gooch may be reached by email at  rgooch@atnf.csiro.au
  18 .\" The postal address is:
  19 .\"   Richard Gooch, c/o ATNF, P. O. Box 76, Epping, N.S.W., 2121, Australia.
  20 .\"
  21 .\"     initctl.8               Richard Gooch   6-NOV-2000
  22 .\"
  23 .TH INITCTL 8 "6 Nov 2000" "Util-Linux Package"
  24 .SH NAME
  25 initctl \- utility to control simpleinit(8)
  26 .SH SYNOPSIS
  27 .nf
  28 \fBneed\fP [\fB-r\fP] \fBservice\fP
  29 .BR display-services
  30 \fBprovide service\fP
  31 .fi
  32 .SH OVERVIEW
  33 The \fBneed\fP programme is designed to help improve the robustness,
  34 scalability and readability of system boot scripts. It is now possible
  35 to write a modularised set of boot scripts without the complex and
  36 fragile numbered symlink scheme used in SysV-style boot scripts. Each
  37 script can simply declare, using \fBneed\fP(8), what must run before
  38 them.
  39 .SH DESCRIPTION for need
  40 The \fBneed\fP programme is a utility that tells \fBsimpleinit\fP(8)
  41 to start a \fIservice\fP (usually a script in \fI/sbin/init.d\fP) and
  42 will wait for the service to become available. If the service is
  43 already available, it will not be started again.
  44
  45 The \fB-r\fP option is used to tell \fBsimpleinit\fP(8) to "roll back"
  46 (stop) services up to (but not including) \fIservice\fP. If
  47 \fIservice\fP is not specified, all services are stopped. The \fB-r\fP
  48 option thus allows the system to be partially or wholly shut down in
  49 an orderly fashion. The \fBshutdown\fP(8) programme still needs to be
  50 run.
  51
  52 .SH DESCRIPTION for display-services
  53 When invoked as \fBdisplay-services\fP it will write the list of
  54 currently available services and the list of failed services to the
  55 standard output.
  56
  57 .SH DESCRIPTION for provide
  58 When invoked as \fBprovide\fP it tells \fBsimpleinit\fP(8) that the
  59 parent (calling) process will be providing a service with name
  60 \fIservice\fP. If the calling process exits successfully (status 0)
  61 the service is deemed to be available. Only one instance of
  62 \fIservice\fP may be started, so alternate providers will block and
  63 may fail.
  64
  65 Using \fBprovide\fP it is possible to have multiple potential
  66 providers for the same (generic) service (e.g. \fBsendmail\fP and
  67 \fBqmail\fP both provide a \fBmta\fP service), where only one actually
  68 provides the service. This may be used by service startup scripts
  69 which check for configuration files.
  70 .SH EXIT CODE
  71 The exit code from \fBneed\fP is 0 if the service was successfully
  72 started, 1 if the service failed badly, and 2 if the service is
  73 unavailable (i.e. disabled in configuration files). These exit codes
  74 reflect the exit codes from the service startup scripts.
  75
  76 The exit code from \fBneed -r\fP is 0 if the service was successfully
  77 stopped, 1 if the service could not be stopped, and 2 if the service
  78 was not available to start with. The service shutdown scripts may only
  79 return 0 (for success) or 1 (for failure).
  80
  81 The exit code from \fBprovide\fP is 0 if the service may be provided,
  82 1 if it may not, and 2 if the parent process is not a child of
  83 init. It may block waiting for another provider which is initialising
  84 the service.
  85 .SH SIGNALS
  86 \fBneed\fP(8) uses \fBSIGUSR1\fP, \fBSIGUSR2\fP and \fBSIGPOLL\fP for
  87 communication with \fBsimpleinit\fP(8). Don't send these signals to
  88 it.
  89 .SH FILES
  90 .PD 0
  91 .TP 20
  92 .BI /dev/initctl
  93 This is the control FIFO, created by \fBsimpleinit\fP(8), which
  94 \fBneed\fP(8) writes commands to.
  95 .SH SEE ALSO
  96 .BR simpleinit (8),
  97 .BR init (8)
  98 .PP
  99 A more complete discussion of the new boot script system, based on
 100 \fBneed\fP(8), is available from:
 101 http://www.atnf.csiro.au/~rgooch/linux/boot-scripts/
 102 .SH AUTHOR
 103 Richard Gooch (rgooch@atnf.csiro.au)
 104 .SH AVAILABILITY
 105 The Util-Linux package is available from:
 106 ftp://ftp.??.kernel.org/pub/linux/utils/util-linux/