Request for peer review of my rc.fetchmail daemon script please

Old_Fogie · 05-17-2012, 01:31 PM

Hello all,

I've been working on a set of build scripts for courier imap, in hopes that I can get it usable enough to post to the mailing list for further work and review.

So because I need to have a lot of mail generated, and fetched for testing purposes, I found that I need fetchmail running as a daemon for my testing.

Since Slackware does not come with a daemon for fetchmail, and yes I know that cron can do it, but that's another issue, I set out to write one for my testing purposes.

If I can get this to be reviewed by others I can put it on Slackwiki or perhaps send it to Mr. V for it to be added (if he wants) to /usr/doc/fetchmail/contrib or the like.

Any how, here's what I've got so far, and it does indeed work.

The only issue, is that when you do something such as "ps aux |grep fetchmail" it will only show "204" instead of the user 'fetchmail' due to posix requirements of a username less that 8 characters.

How to set up user and group info is at the end.

Please scrutinize it, rip it apart, yet at me, it's all good

Ok here's the code:

Code:

#!/bin/sh

INTERVAL=30
CONFIG=/etc/fetchmailrc

case "$1" in
  start)
if [ -e /var/run/fetchmail/.fetchmail.pid ]; then
  echo
  echo "The fetchmail daemon appears to be running by the presence \
of /var/run/fetchmail/.fetchmail.pid."
  echo
  echo "To resolve this, try: fetchmail -quit or simply rm \
/var/run/fetchmail/.fetchmail.pid"
  echo
  echo "Start command failed: exiting now"
  echo
exit
fi
    echo "Starting fetchmail with uid/gid pair of `id fetchmail`"
      # add the -v after CONFIG to get verbose output
      # add the --invisible option to stop fetchmail adding itself to the headers
      su - fetchmail -s /bin/bash -c "/usr/bin/fetchmail -L /var/log/fetchmail -d \
        $INTERVAL -f $CONFIG -v --invisible"
      echo "fetchmail: starting at `date`" >> /var/log/fetchmail
    ;;
  stop)
    echo "Stopping fetchmail"
      su - fetchmail -s /bin/bash -c "/usr/bin/fetchmail -quit"
      echo "fetchmail: stopped at `date`" >> /var/log/fetchmail
      echo "" >> /var/log/fetchmail
    ;;
  restart)
    $0 stop
    sleep 1
    $0 start
    ;;
  *)
    echo "usage: $0 {start|stop|restart}"  
esac
exit 0


# slackware commands to add fetchmail user and group
#groupadd -g 204 fetchmail
#useradd -u 204 -d /var/run/fetchmail -s /bin/false -g fetchmail fetchmail

# create fetchmails home:
#install -d -o fetchmail -g fetchmail -m700 /var/run/fetchmail

# create our config file template
#touch /etc/fetchamilrc <------------- if you don't have one already there
#chmod 600 /etc/fetchamilrc
#chown fetchmail:fetchmail /etc/fetchmailrc <------------if you dont have one there already

# crate the log file for fetchmail to use
#touch /var/log/fetchmail
#chown fetchmail:fetchmail /var/log/fetchmail
#chmod 600 /var/log/fetchmail

unSpawn · 05-18-2012, 11:14 AM

Here's my take on things keeping it simple:

Code:

#!/bin/sh

NAME="fetchmail"
CONFIG=/etc/${NAME}rc
BINARY="/usr/bin/${NAME}"
PIDDIR="/var/run/${NAME}"
LOGFILE="/var/log/${NAME}.log"
INTERVAL=30
umask 027

preflight() { # Add user and group, configuration and log file
getent group ${NAME} >/dev/null 2>&1; 
[ $? -ne 0 ] && { groupadd -g 204 ${NAME}; useradd -u 204 -d ${PIDDIR} -s /bin/false -g ${NAME} ${NAME};
install -d -o ${NAME} -g ${NAME} -m 0700 ${PIDDIR}; }
[ ! -e ${CONFIG} ] && { touch ${CONFIG}; chmod 600 ${CONFIG}; chown ${NAME}:${NAME} ${CONFIG}; }
[ ! -e /var/log/${NAME} ] && { touch ${${LOGFILE}}; chmod 600 ${${LOGFILE}}; chown ${NAME}:${NAME} ${${LOGFILE}}; }
}

isStopped() { # Stop Fetchmail if necessary
pgrep -f "${BINARY} -L ${${LOGFILE}}" >/dev/null 2>&1
case $? in 0) $0 stop;;	*) rm -f "${PIDDIR}/.${NAME}.pid";; esac
}

case "$1" in
 start)  preflight; isStopped
  echo "Starting ${NAME} as `id ${NAME}`"
  su - ${NAME} -s /bin/bash -c "${BINARY} -L ${${LOGFILE}} -d $INTERVAL -f ${CONFIG}"
  logger -f "${${LOGFILE}}" -t "${NAME}" "Starting."
 ;;
 stop)
  echo "Stopping ${NAME}"
  su - ${NAME} -s /bin/bash -c "${BINARY} -quit"
  logger -f "${${LOGFILE}}" -t "${NAME}" "Stopped."
  isStopped
 ;;
 restart)
  $0 stop; sleep 1; $0 start
 ;;
 *)
  echo "usage: $0 {start|stop|restart}"
  exit 0
 ;;
esac

exit 0

Old_Fogie · 05-20-2012, 08:14 PM

Thank you verfy much for the assistnace unSpawn.

There are a few commands in that script you posted that I am not familiar with. So I've been reading up on them.

A question for you please, what does the "*" do in the following section:

Code:

isStopped() { # Stop Fetchmail if necessary
pgrep -f "${BINARY} -L ${${LOGFILE}}" >/dev/null 2>&1
case $? in 0) $0 stop;;    *) rm -f "${PIDDIR}/.${NAME}.pid";; esac
}

Thank you again :)

Richard Cranium · 05-21-2012, 01:20 AM

Quote:

Originally Posted by Old_Fogie

A question for you please, what does the "*" do in the following section:

Code:

isStopped() { # Stop Fetchmail if necessary
pgrep -f "${BINARY} -L ${${LOGFILE}}" >/dev/null 2>&1
case $? in 0) $0 stop;;    *) rm -f "${PIDDIR}/.${NAME}.pid";; esac
}

Well, if you write the case statement like this...

Code:

case $? in
    0)
        $0 stop
        ;;
    *)
        rm -f "${PIDDIR}/.${NAME}.pid"
        ;;
esac

...it might be more clear. The case statement attempts to match the individual case patterns in order. The "*" pattern matches anything, so it is more-or-less used as a default.

You can run the "man bash" command and search for the case command's documentation, which tells you other interesting details too.