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.\" ========================================================================
.\"
.IX Title "ps-watcher 8"
.TH ps-watcher 8 "2008-12-25" "perl v5.8.8" "User Contributed Perl Documentation"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH "NAME"
ps\-watcher \- monitors various processes based on ps\-like information.
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
\&\fBps-watcher\fR [\fIoptions\fR...]
            [\f(CW\*(C`\-\-config\*(C'\fR] \fIconfig-file\fR
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
Periodically a list of processes obtained via \f(CW\*(C`ps\*(C'\fR. More precisely
each item in the list contains the process name (just what's listed in
the \*(L"cmd\*(R" field, not the full command and arguments) and its process
id (pid). A configuration file specifies a list of Perl
regular-expression patterns to match the processes against. For each
match, a Perl expression specified for that pattern is evaluated. The
evaluated expression can refer to variables which are set by ps and
pertain to the matched process(es), for example the amount memory
consumed by the process, or the total elapsed time. Some other
variables are set by the program, such as the number of times the
process is running. If the Perl expression for a matched pattern
evaluates true, then an action can be run such as killing the program,
restarting it, or mailing an alert, or running some arbitrary Perl
code.
.PP
Some things you might want to watch a daemon or process for:
.IP "\(bu" 2
check that it is running (hasn't died)
.IP "\(bu" 2
ensure it is not running too many times
.IP "\(bu" 2
isn't consuming too much memory (perhaps a memory leak), or I/O
.PP
Some actions you might want to take:
.IP "\(bu" 2
restart a process
.IP "\(bu" 2
kill off rampant processes
.IP "\(bu" 2
send an alert about any of the conditions listed above
.PP
Depending on options specfied, this program can be run as a daemon,
run once (which is suitable as a \f(CW\*(C`cron\*(C'\fR job), or run not as a daemon
but still continuously (which may be handy in testing the program or
your configuration).
.Sh "\s-1OPTIONS\s0"
.IX Subsection "OPTIONS"
.IP "\-\-help" 4
.IX Item "--help"
Print a usage message on standard error and exit with a return code
of 100.
.Sp

.IP "\-\-doc" 4
.IX Item "--doc"
Extact the full documentation that you are reading now, print it and
exit with a return code of 101.
.Sp

.IP "\-\-version" 4
.IX Item "--version"
Print the version release on standard output and exit with a return
code of 10.
.Sp

.IP "\-\-debug \fInumber\fR" 4
.IX Item "--debug number"
Give debugging output. The higher the number, the more the output. The
default is 0 = none. 2 is the most debugging output.
.IP "[\-\-config] \fIconfiguration file\fR" 4
.IX Item "[--config] configuration file"
Specify configuration file. .
.Sp
See \*(L"\s-1CONFIGURATION\s0 \s-1FILE\s0 \s-1FORMAT\s0\*(R" below for information on the format
of the configuration file and \*(L"\s-1EXAMPLE\s0 \s-1CONFIGURATION\s0\*(R" for a complete
example of a configuration file.
.Sp

.IP "\-\-log [\fIlog file\fR]" 4
.IX Item "--log [log file]"
Send or don't send error and debugging output to a log file. If option
is given but no logfile is specified, then use \s-1STDERR\s0. The default is
no error log file.  See also \-\-syslog below.
.Sp

.IP "\-\-syslog | \-\-nosyslog" 4
.IX Item "--syslog | --nosyslog"
Send or don't send error and debugging output to syslog. The default
is to syslog error and debug output.
.Sp

.IP "\-\-daemon | \-\-nodaemon" 4
.IX Item "--daemon | --nodaemon"
Run or don't as a daemon.
.Sp

.IP "\-\-path \fIsearch-path\fR" 4
.IX Item "--path search-path"
Specify the executable search path used in running commands.
.IP "\-\-ps\-prog \fIprogram\fR" 4
.IX Item "--ps-prog program"
One can specify the command that gives ps information. By default, the
command is \fI/bin/ps\fR.
.Sp

.IP "\-\-run | \-\-norun" 4
.IX Item "--run | --norun"
do/don't run actions go through the motions as though we were going
to. This may be useful in debugging.
.Sp

.IP "\-\-sleep \fIinterval in seconds\fR" 4
.IX Item "--sleep interval in seconds"
It is expected that one might want to run ps-watcher over and over
again. In such instances one can specify the amount of time between
iterations with this option.
.Sp
If a negative number is specified the program is run only once.
.Sp

.Sh "\s-1CONFIGURATION\s0 \s-1FILE\s0 \s-1MODIFICATION\s0 \s-1AND\s0 \s-1SIGNAL\s0 \s-1HANDLING\s0"
.IX Subsection "CONFIGURATION FILE MODIFICATION AND SIGNAL HANDLING"
Periodically ps-watcher checks to see if the configuration file
that it was run against has changed. If so, the program rereads the
configuration file.
.PP
More precisely, the checks are done after waking up from a slumber.
If the sleep interval is long (or if you are impatient), you can
probably force the program to wake up using a \s-1HUP\s0 signal.
.PP
At any time you can increase the level of debug output by sending a
\&\s-1USR1\s0 signal to the ps-watcher process. Similarly you can decrease the
level of debug output by sending the process a \s-1USR2\s0 signal.
.PP
It is recommended that you terminate ps-watcher via an \s-1INT\s0, \s-1TERM\s0, or \s-1QUIT\s0
signal.
.SH "CONFIGURATION FILE FORMAT"
.IX Header "CONFIGURATION FILE FORMAT"
The format of a configuration file is a series of fully qualified
filenames enclosed in square brackets followed by a number of
parameter lines. Each parameter line has a parameter name followed by
an \*(L"equal\*(R" sign and finally value. That is:
.PP
.Vb 5
\& # This is a comment line
\& ; So is this.
\& [process\-pattern1]
\&  parameter1 = value1
\&  parameter2 = value2
\&
\& [process\-pattern2]
\&  parameter1 = value3
\&  parameter2 = value4
.Ve
.PP
Comments start with # or ; and take effect to the end of the line.
.PP
This should be familiar to those who have worked with text-readible
Microsoft \f(CW\*(C`.INI\*(C'\fR files.
.PP
Note process patterns, (\fIprocess\-pattern1\fR and \fIprocess\-pattern2\fR
above) must be unique. If there are times when you may want to
refer to the same process, one can be creative to make these unique.
e.g. \fIcron\fR and \fI[c]ron\fR which refer to the same process even
though they \fIappear\fR to be different.
.PP
As quoted directly from the Config::IniFiles documentation:
.PP
Multiline or multivalued fields may also be defined ala \s-1UNIX\s0
\&\*(L"here document\*(R" syntax:
.PP
.Vb 4
\&  Parameter=<<EOT
\&  value/line 1
\&  value/line 2
\&  EOT
.Ve
.PP
You may use any string you want in place of \*(L"\s-1EOT\s0\*(R".  Note
that what follows the \*(L"<<\*(R" and what appears at the end of
the text \fImust\fR match exactly, including any trailing
whitespace.
.PP
There are two special \*(L"process patterns\*(R": \f(CW$PROLOG\fR and \f(CW$EPILOG\fR, the
former should appear first and the latter last.
.PP
You can put perl code to initialize variables here and do cleanup
actions in these sections using \*(L"perl-action.\*(R"
.PP
A description of parameters names, their meanings and potential values
follows.
.IP "trigger" 4
.IX Item "trigger"
This parameter specifies the condition on which a process action is
fired.  The condition is evaluated with Perl \fIeval()\fR and should
therefore return something which is equivalent to \*(L"true\*(R" in a Perl
expression.
.Sp
If no trigger is given in a section, true or 1 is assumed and
the action is unconditionally triggered.
.Sp
Example:
.Sp
.Vb 8
\&  # Match if httpd has not spawned enough (<4) times. NFS and databases
\&  # daemons typically spawn child processes.  Since the program
\&  # matches against the command names, not commands and arguments,
\&  # something like: ps \-ef | grep httpd won\*(Aqt match the below.
\&  # If you want to match against the command with arguments, see
\&  # the example with $args below.
\&  [httpd$]
\&  trigger = $count <= 4
.Ve
.IP "occurs" 4
.IX Item "occurs"
This parameter specifies how many times an action should be performed
on processes matching the section trigger. Acceptable values are
\&\*(L"every\*(R", \*(L"first\*(R", \*(L"first-trigger\*(R", and \*(L"none\*(R".
.Sp
Setting the occurs value to \*(L"none\*(R" causes the the trigger to be
evaluated when there are no matching processes.  Although one might
think \*(L"$count == 0\*(R" in the action expression would do the same thing,
currently as coded this does not work.
.Sp
Setting the occurs value to \*(L"first\*(R" causes the process-pattern rule to
be finished after handling the first rule that matches, whether or not the
trigger evaluated to true.
.Sp
Setting the occurs value to \*(L"first-trigger\*(R" causes the process-pattern
rule to be finished after handling the first rule that matches \fIand\fR
the trigger evaluates to true.
.Sp
If the item parameter is not specified, \*(L"first\*(R" is assumed.
.Sp
Examples:
.Sp
.Vb 3
\&  [.]
\&  occurs = first
\&  action = echo "You have $count processes running"
\&
\&  # Note in the above since there is no trigger specified,
\&  #   occurs = first
\&  # is the same thing as 
\&  #   occurs = first\-trigger
\&
\&  [.?]
\&  trigger = $vsz > 1000
\&  occurs  = every
\&  action  = echo "Large program $command matches $ps_pat: $vsz KB"
\&
\&  # Fire if /usr/sbin/syslogd is not running.
\&  # Since the program matches against the command names, not commands and
\&  # arguments, something like: 
\&  #   ps \-ef | grep /usr/sbin/syslogd
\&  # won\*(Aqt match the below.
\&  [(/usr/sbin/)?syslogd]
\&  occurs = none
\&  action = /etc/init.d/syslogd start
.Ve
.IP "action" 4
.IX Item "action"
This specifies the action, a command that gets run by the system
shell, when the trigger condition is evaluated to be true.
.Sp
Example:
.Sp
.Vb 1
\& action = /etc/init.d/market_loader.init restart
.Ve
.IP "perl-action" 4
.IX Item "perl-action"
This specifies Perl statements to be eval'd. This can be especially
useful in conjunction with \f(CW$PROLOG\fR and \f(CW$EPILOG\fR sections to make tests
across collections of process and do things which ps-watcher
would otherwise not be able to do.
.Sp
Example:
.Sp
.Vb 5
\&  # A Perl variable initialization.
\&  # Since ps\-watcher runs as a daemon it\*(Aqs a good idea
\&  # to (re)initialize variables before each run.
\&  [$PROLOG]
\&    perl\-action = $root_procs=0;
\&
\&  # Keep track of how many root processes we are running
\&  [.*]
\&    perl\-action = $root_procs++ if $uid == 0
\&    occurs  = every
\&
\&  # Show this count.
\&  [$EPILOG]
\&    action  = echo "I counted $root_procs root processes"
.Ve
.Sh "\s-1EXPANDED\s0 \s-1VARIABLES\s0 \s-1IN\s0 \s-1TRIGGER/ACTION\s0 \s-1CLAUSES\s0"
.IX Subsection "EXPANDED VARIABLES IN TRIGGER/ACTION CLAUSES"
Any variables defined in the program can be used in pattern or
action parameters. For example, \f(CW$program\fR can be used to refer to 
the name of this program ps-watcher.
.PP
The following variables can be used in either the pattern or action
fields.
.ie n .IP "$action" 4
.el .IP "\f(CW$action\fR" 4
.IX Item "$action"
A string containing the text of the action to run.
.Sp

.ie n .IP "$perl_action" 4
.el .IP "\f(CW$perl_action\fR" 4
.IX Item "$perl_action"
A string containing the text of the perl_action to run.
.Sp

.ie n .IP "$ps_pat" 4
.el .IP "\f(CW$ps_pat\fR" 4
.IX Item "$ps_pat"
The Perl regular expression specified in the beginning of the section.
.Sp

.ie n .IP "$command" 4
.el .IP "\f(CW$command\fR" 4
.IX Item "$command"
The command that matched \f(CW$ps_pat\fR.
.Sp
The Perl regular expression specified in the beginning of the section.
Normally processes will not have funny characters in them. Just in
case, backticks in \f(CW$command\fR are escaped.
.Sp
Example:
.Sp
.Vb 2
\&  # List processes other than emacs (which is a known pig) that use lots
\&  # of virtual memory
\&
\&  [.*]
\&  trigger = $command !~ /emacs$/ && $vsz > 10
\&  action  = echo \e"Looks like you have a big \e$command program: \e$vsz KB\e"
.Ve
.Sp

.ie n .IP "$count" 4
.el .IP "\f(CW$count\fR" 4
.IX Item "$count"
The number of times the pattern matched. Presumably the number of
processes of this class running.
.Sp

.ie n .IP "$trigger" 4
.el .IP "\f(CW$trigger\fR" 4
.IX Item "$trigger"
A string containing the text of the trigger.
.PP
A list of variables specific to this program or fields commonly found in
\&\f(CW\*(C`ps\*(C'\fR output is listed below followed by a description of the more
common ones. See also \f(CW\*(C`ps\*(C'\fR for a more complete
description of the meaning of the field.
.PP
.Vb 11
\& uid euid ruid gid egid rgid alarm blocked bsdtime c caught
\&cputime drs dsiz egroup eip esp etime euser f fgid
\&fgroup flag flags fname fsgid fsgroup fsuid fsuser fuid fuser
\&group ignored intpri lim longtname m_drs m_trs maj_flt majflt
\&min_flt  minflt ni nice nwchan opri pagein pcpu pending pgid pgrp
\&pmem ppid pri rgroup rss rssize rsz ruser s sess session
\&sgi_p sgi_rss sgid sgroup sid sig sig_block sig_catch sig_ignore
\&sig_pend sigcatch sigignore sigmask stackp start start_stack start_time
\&stat state stime suid suser svgid svgroup svuid svuser sz time timeout
\&tmout tname tpgid trs trss tsiz tt tty tty4 tty8 uid_hack uname
\&user vsize vsz wchan
.Ve
.PP
Beware though, in some situations ps can return multiple lines for a
single process and we will use just one of these in the trigger. In
particular, Solaris's \f(CW\*(C`ps\*(C'\fR will return a line for each \s-1LWP\s0 (light-weight
process). So on Solaris, if a trigger uses variable lwp, it may or may
not match depending on which single line of the multiple \f(CW\*(C`ps\*(C'\fR lines is
used.
.PP

.ie n .IP "$args" 4
.el .IP "\f(CW$args\fR" 4
.IX Item "$args"
The command along with its command arguments. It is possible that this
is might get truncated at certain length (if ps does likewise as is
the case on Solaris).
.Sp

.ie n .IP "$ppid" 4
.el .IP "\f(CW$ppid\fR" 4
.IX Item "$ppid"
The parent process id.
.Sp

.ie n .IP "$stime" 4
.el .IP "\f(CW$stime\fR" 4
.IX Item "$stime"
The start time of the process.
.Sp

.ie n .IP "$etime" 4
.el .IP "\f(CW$etime\fR" 4
.IX Item "$etime"
The end time of the process.
.Sp

.ie n .IP "$pmem" 4
.el .IP "\f(CW$pmem\fR" 4
.IX Item "$pmem"
The process memory.
.Sp

.ie n .IP "$pcpu" 4
.el .IP "\f(CW$pcpu\fR" 4
.IX Item "$pcpu"
The percent \s-1CPU\s0 utilization.
.Sp

.ie n .IP "$tty" 4
.el .IP "\f(CW$tty\fR" 4
.IX Item "$tty"
The controlling tty.
.Sp

.ie n .IP "$vsz" 4
.el .IP "\f(CW$vsz\fR" 4
.IX Item "$vsz"
Virtual memory size of the process
.Sh "\s-1OTHER\s0 \s-1THINGS\s0 \s-1IN\s0 \s-1TRIGGER\s0 \s-1CLAUSES\s0"
.IX Subsection "OTHER THINGS IN TRIGGER CLAUSES"
To make testing against elapsed time easier, a function \f(CW\*(C`elapse2sec()\*(C'\fR
has been written to parse and convert elapsed time strings in the 
format \f(CW\*(C`dd\-hh:mm:ss\*(C'\fR and a number of seconds.
.PP
Some constants for the number of seconds in a minute, hour, or day
have also been defined. These are referred to as \f(CW\*(C`MINS\*(C'\fR, \f(CW\*(C`HOURS\*(C'\fR,
and \f(CW\*(C`DAYS\*(C'\fR respectively and they have the expected definitions:
.PP
.Vb 3
\&  use constant MINS   => 60;
\&  use constant HOURS  => 60*60;
\&  use constant DAYS   => HOURS * 24;
.Ve
.PP
Here is an example of the use of \f(CW\*(C`elapsed2sec()\*(C'\fR:
.PP
.Vb 7
\&  # Which processes have been running for more than 3 hours?
\&  # Also note use of builtin\-function elapsed2secs, variable $etime
\&  # and builtin\-function HOURS
\&  [.]
\&    trigger = elapsed2secs(\*(Aq$etime\*(Aq) > 1*DAYS
\&    action  = echo "$command has been running more than 1 day ($etime)"
\&    occurs  = every
.Ve
.PP
Please note the quotes around '$etime'.
.SH "EXAMPLE CONFIGURATION"
.IX Header "EXAMPLE CONFIGURATION"
.Vb 1
\&  # Comments start with # or ; and go to the end of the line.
\&
\&  # The format for each entry is in Microsoft .INI form:
\&  # [process\-pattern]
\&  # trigger = perl\-expression
\&  # action  = program\-and\-arguments\-to\-run
\&
\&  [httpd$]
\&    trigger = $count < 4
\&    action  = echo "$trigger fired \-\- You have $count httpd sessions."
\&
\&  [.]
\&  trigger = $vsz > 10
\&  action  = echo "Looks like you have a big $command program: $vsz KB"
\&
\&  # Unfortunately we have use a different pattern below. (Here we use
\&  # ".?" instead of ".".) In effect the the two patterns mean
\&  # test every process.
\&  [.?]
\&    trigger = elapsed2secs(\*(Aq$etime\*(Aq) > 2*MINS && $pcpu > 40
\&    occurs  = every
\&    action  = <<EOT
\&     echo "$command used $pcpu% CPU for the last $etime seconds" | /bin/mail root
\&     kill \-TERM $pid
\&  EOT
\&
\&  # Scripts don\*(Aqt show as the script name as the command name on some
\&  # operating systems.  Rather the name of the interpreter is listed
\&  # (e.g. bash or perl) Here\*(Aqs how you can match against a script.
\&  # BSD/OS is an exception: it does give the script name rather than
\&  # the interpreter name.
\&  [/usr/bin/perl]
\&    trigger = \e$args !~ /ps\-watcher/
\&    occurs  = every
\&    action  = echo "***found perl program ${pid}:\en $args"
.Ve
.ie n .SH "Using $PROLOG for getting non-ps information"
.el .SH "Using \f(CW$PROLOG\fP for getting non-ps information"
.IX Header "Using $PROLOG for getting non-ps information"
Here is an example to show how to use ps-watcher to do something not
really possible from ps: check to see if a \fIport\fR is active.  We make
use of lsof to check port 3333 and the \f(CW$PROLOG\fR make sure it runs.
.PP
.Vb 6
\&  [$PROLOG]
\&    occurs  = first
\&    trigger = { \e$x=\`lsof \-i :3333 >/dev/null 2>&1\`; \e$? >> 8 }
\&    action  = <<EOT
\&    put\-your\-favorite\-command\-here arg1 arg2 ...
\&  EOT
.Ve
.SH "SECURITY CONSIDERATIONS"
.IX Header "SECURITY CONSIDERATIONS"
Any daemon such as this one which is sufficiently flexible is a
security risk. The configuration file allows arbitrary commands to be
run. In particular if this daemon is run as root and the configuration
file is not protected so that it can't be modified, a bad person could
have their programs run as root.
.PP
There's nothing in the ps command or ps-watcher, that requires one to
run this daemon as root.
.PP
So as with all daemons, one needs to take usual security precautions
that a careful sysadmin/maintainer of a computer would. If you can run
any daemon as an unprivileged user (or with no privileges), do it!  If
not, set the permissions on the configuration file and the directory
it lives in.
.PP
This program can also run chrooted and there is a \f(CW\*(C`\-\-path\*(C'\fR option
that is available which can be used to set the executable search path.
All commands used by ps-watcher are fully qualified, and I generally
give a full execution path in my configuration file, so consider using
the option \f(CW\*(C`\-\-path=\*(Aq\*(Aq\*(C'\fR.
.PP
Commands that need to be run as root you can run via \f(CW\*(C`sudo\*(C'\fR.  I often
run process accounting which tracks all commands run. Tripwire may be
useful to track changed configuration files.
.SH "TROUBLESHOOTING"
.IX Header "TROUBLESHOOTING"
To debug a configuration file the following options are useful:
.PP
.Vb 1
\&   ps\-watcher \-\-log \-\-nodaemon \-\-sleep \-1 \-\-debug 2 *config\-file*
.Ve
.PP
For even more information and control try running the above under the
perl debugger, e.g.
.PP
.Vb 1
\&   perl \-d ps\-watcher \-\-log \-\-nodaemon \-\-sleep \-1 \-\-debug 2 *config\-file*
.Ve
.SH "BUGS"
.IX Header "BUGS"
Well, some of these are not so much a bug in ps-watcher so much as a
challenge to getting ps-watcher to do what you want it to do.
.PP
One common problem people run in into is understanding exactly what
the process variables mean. The manual page \fIps\fR\|(1) should be of
help, but I've found some of the descriptions either a bit vague or
just plain lacking.
.PP
Sometimes one will see this error message when debug tracing is turned on:
.PP
.Vb 1
\&  ** debug ** Something wrong getting ps variables
.Ve
.PP
This just means that the process died between the time ps-watcher first
saw the existence of the process and the time that it queried
variables.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
See also \fIps\fR\|(1) and \fIsyslogd\fR\|(8).
.PP
Another cool program doing ps-like things is \f(CW\*(C`xps\*(C'\fR. Well okay, it's
another program I distributed. It shows the process tree dynamically
updated using X Motif and tries to display the output \*(L"attractively\*(R"
but fast. You can the find the homepage at
<http://motif\-pstree.sourceforge.net> and it download via
<http://prdownloads.sourceforge.net/motif\-pstree?sort_by=date&sort=desc>
.SH "AUTHOR"
.IX Header "AUTHOR"
Rocky Bernstein (rocky@gnu.org)
.SH "COPYRIGHT"
.IX Header "COPYRIGHT"
.Vb 6
\&  Copyright (C) 2000, 2002, 2003, 2004, 2005, 2006, 2008
\&  Rocky Bernstein, email: rocky@gnu.org.
\&  This program is free software; you can redistribute it and/or modify
\&  it under the terms of the GNU General Public License as published by
\&  the Free Software Foundation; either version 2 of the License, or
\&  (at your option) any later version.
\&
\&  This program is distributed in the hope that it will be useful,
\&  but WITHOUT ANY WARRANTY; without even the implied warranty of
\&  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
\&  GNU General Public License for more details.
\&
\&  You should have received a copy of the GNU General Public License
\&  along with this program; if not, write to the Free Software
\&  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
.Ve