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runtrap(8)			    runtools			      runtrap(8)

NAME
     runtrap - run a program with a signal trapper

SYNOPSIS
     runtrap [-hV] id trapper program [ args ...  ]

DESCRIPTION
     runtrap  starts  program  with  any  args and monitors it as a long-running
     process.  If runtrap notices that program terminates, it restarts it.

     Whenever runtrap itself receives any signal it can catch,	it  invokes  the
     argument given by trapper in this form:

	    trapper ``trap'' id pid signum signame

     Where:

	    trapper

		   The	name  of an executable specified in the trapper argument
		   on the command-line.

	    ``trap''

		   The verbatim string ``trap''.

	    id

		   A simple string specified in the id argument on the	command-
		   line.

	    pid

		   The process ID of the program that runtrap is monitoring.

	    signum

		   The	numeric decimal representation of the signal received by
		   runtrap.

	    signame

		   The symbolic name for the signal received by runtrap.

     Presumably trapper is a short-running program designed to perform some spe-
     cial handling of signals destined for  program.   After  invoking	trapper,
     runtrap waits for it to complete and then resumes monitoring program.

     If  runtrap  receives a SIGTERM, it flags itself to terminate.  It then in-
     vokes trapper as above with SIGTERM arguments.   When  program  terminates,
     runtrap itself then exits normally.

OPTIONS
     -h     Help.  Print a brief usage message to stderr and exit.

     -V     Version.  Print the version number to stderr and exit.

EXAMPLES
     runtrap  is  designed for use in perpetrate(5) runscripts for services that
     need special signal handling.  The example below shows how an rc.main  run-
     script may be multiplexed to handle ``trap'' targets:

	    #!/bin/sh
	    exec 2>&1

	    TARGET=${1}
	    SVNAME=${2}

	    start() {
	      echo "starting ${SVNAME} ..."
	      exec runtrap ${SVNAME} ./rc.main /usr/sbin/foo -f
	    }

	    reset() {
	      echo "resetting ${SVNAME} ..."
	      #...
	    }

	    trap() {
	      SVPID=${3}
	      SIGNUM=${4}
	      SIGNAME=${5}
	      echo "trapping ${SVNAME} for signal ${SIGNAME} ..."
	      kill -${SIGNUM} ${SVPID}
	    }

	    eval ${TARGET} "$@"

	    ### EOF

AUTHOR
     Wayne Marshall, http://b0llix.net/perp/

SEE ALSO
     runtools_intro(8),   runargs(8),  runargv0(8),  runchoom(8),  rundetach(8),
     rundeux(8), runenv(8), runfile(8),  runlimit(8),  runlock(8),  runpause(8),
     runsession(8), runtool(8), runuid(8), perpd(8), perpetrate(5)

runtools-2.07			  January 2013			      runtrap(8)

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