freebsd-skq/sbin/rcorder/rcorder.8

.\"	$NetBSD: rcorder.8,v 1.3 2000/07/17 14:16:22 mrg Exp $
.\"
.\" Copyright (c) 1998
.\"	Perry E. Metzger.  All rights reserved.
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.\" modification, are permitted provided that the following conditions
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.\"    must display the following acknowledgment:
.\"	This product includes software developed for the NetBSD Project
.\"	by Perry E. Metzger.
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.\" $FreeBSD$
.\"
.Dd September 8, 2020
.Dt RCORDER 8
.Os
.Sh NAME
.Nm rcorder
.Nd print a dependency ordering of interdependent files
.Sh SYNOPSIS
.Nm
.Op Fl gp
.Op Fl k Ar keep
.Op Fl s Ar skip
.Ar
.Sh DESCRIPTION
The
.Nm
utility is designed to print out a dependency ordering of a set of
interdependent files.
Typically it is used to find an execution
sequence for a set of shell scripts in which certain files must be
executed before others.
.Pp
Each file passed to
.Nm
must be annotated with special lines (which look like comments to the
shell) which indicate the dependencies the files have upon certain
points in the sequence, known as
.Dq conditions ,
and which indicate, for each file, which
.Dq conditions
may be expected to be filled by that file.
.Pp
Within each file, a block containing a series of
.Ql REQUIRE ,
.Ql PROVIDE ,
.Ql BEFORE
and
.Ql KEYWORD
lines must appear.
The format of the lines is rigid.
Each line must begin with a single
.Ql # ,
followed by a single space, followed by
.Ql PROVIDE\&: ,
.Ql REQUIRE\&: ,
.Ql BEFORE\&: ,
or
.Ql KEYWORD\&: .
No deviation is permitted.
Each dependency line is then followed by a series of conditions,
separated by whitespace.
Multiple
.Ql PROVIDE ,
.Ql REQUIRE ,
.Ql BEFORE
and
.Ql KEYWORD
lines may appear, but all such lines must appear in a sequence without
any intervening lines, as once a line that does not follow the format
is reached, parsing stops.
.\" Note that for historical reasons REQUIRES, PROVIDES, and KEYWORDS
.\" are also accepted in addition to the above, but not documented so
.\" that they can be deprecated at some point in the future.
.Pp
The options are as follows:
.Bl -tag -width "-k keep"
.It Fl g
Produce a GraphViz (.dot) of the complete dependency graph instead of
plaintext calling order list.
.It Fl k Ar keep
Add the specified keyword to the
.Dq "keep list" .
If any
.Fl k
option is given, only those files containing the matching keyword are listed.
This option can be specified multiple times.
.It Fl p
Generate ordering suitable for parallel startup, placing files that can be
executed simultaneously on the same line.
.It Fl s Ar skip
Add the specified keyword to the
.Dq "skip list" .
If any
.Fl s
option is given, files containing the matching keyword are not listed.
This option can be specified multiple times.
.El
.Pp
An example block follows:
.Bd -literal -offset indent
# REQUIRE: networking syslog
# REQUIRE: usr
# PROVIDE: dns nscd
.Ed
.Pp
This block states that the file in which it appears depends upon the
.Ql networking ,
.Ql syslog ,
and
.Ql usr
conditions, and provides the
.Ql dns
and
.Ql nscd
conditions.
.Pp
A file may contain zero
.Ql PROVIDE
lines, in which case it provides no conditions, and may contain zero
.Ql REQUIRE
lines, in which case it has no dependencies.
There must be at least one file with no dependencies in the set of
arguments passed to
.Nm
in order for it to find a starting place in the dependency ordering.
.Sh KEYWORDS
There are several
.Em KEYWORDs
in use:
.Bl -tag -width "shutdown" -offset indent
.It Sy firstboot , nojail , nojailvnet , nostart
Used by
.Xr rc 8 .
.It Sy resume
Used by
.Nm /etc/rc.resume
(see
.Xr acpiconf 8 )
.It Sy shutdown
Used by
.Xr rc.shutdown 8 .
.El
.Sh EXAMPLES
Print the dependency ordering of the services from the base system and
.Xr ports 7 :
.Bd -literal -offset indent
$ rcorder /etc/rc.d/* /usr/local/etc/rc.d/*
.Ed
.Pp
Count the number of services in the base system, which specify the
.Sy shutdown
keyword, while skipping those with
.Sy firstboot
and
.Sy nojailvnet :
.Bd -literal -offset indent
$ rcorder -k nostart -s firstboot -s nojailvnet /etc/rc.d/*  | wc -l
       3
.Ed
.Sh DIAGNOSTICS
The
.Nm
utility may print one of the following error messages and exit with a non-zero
status if it encounters an error while processing the file list.
.Bl -diag
.It "Requirement %s in file %s has no providers."
No file has a
.Ql PROVIDE
line corresponding to a condition present in a
.Ql REQUIRE
line in another file.
.It "Circular dependency on provision %s in file %s."
A set of files has a circular dependency which was detected while
processing the stated condition.
Loop visualization follows this message.
.It "Circular dependency on file %s."
A set of files has a circular dependency which was detected while
processing the stated file.
.It "%s was seen in circular dependencies for %d times."
Each node that was a part of circular dependency loops reports total number of
such encounters.
Start with files having biggest counter when fighting with broken dependencies.
.El
.Sh DIAGNOSTICS WITH GRAPHVIZ
Direct dependency is drawn with solid line,
.Ql BEFORE
dependency is drawn as a dashed line.
Each node of a graph represents an item from
.Ql PROVIDE
lines.
In case there are more than one file providing an item, a list of filenames
shortened with
.Xr basename 3
is shown.
Shortened filenames are also shown in case
.Ql PROVIDE
item does not match file name.
.Pp
Edges and nodes where circular dependencies were detected are drawn bold red.
If a file has an item in
.Ql REQUIRE
or in
.Ql BEFORE
that could not be provided,
this missing provider and the requirement will be drawn bold red as well.
.Sh SEE ALSO
.Xr acpiconf 8 ,
.Xr rc 8 ,
.Xr rc.shutdown 8 ,
.Xr service 8
.Sh HISTORY
The
.Nm
utility appeared in
.Nx 1.5 .
.Nm
utility first appeared in
.Fx 5.0 .
.Sh AUTHORS
.An -nosplit
Written by
.An Perry E. Metzger Aq Mt perry@piermont.com
and
.An Matthew R. Green Aq Mt mrg@eterna.com.au .
.Sh BUGS
The
.Ql REQUIRE
keyword is misleading:
It does not describe which daemons have to be running before a script
will be started.
It describes which scripts must be placed before it in
the dependency ordering.
For example,
if your script has a
.Ql REQUIRE
on
.Ql sshd ,
it means the script must be placed after the
.Ql sshd
script in the dependency ordering,
not necessarily that it requires
.Nm sshd
to be started or enabled.