Hi Scott
On 4/9/21 2:40 AM, Scott Andrews wrote:
# Function: pidofproc [-p pidfile] pathname
# The pidofproc function shall return one or more process
# identifiers for a particular daemon using the algorithm
# given above. Only process identifiers of running
# processes should be returned. Multiple process
# identifiers shall be separated by a single space.
# The pidofproc function shall return the LSB defined exit
# status codes for "status". It shall return 0 if the
# program is running and not 0 otherwise.
#
# If the status action is requested, the init script will return
# the following exit status codes.
# 0 program is running or service is OK
# 1 program is dead and /var/run pid file exists
# 2 program is dead and /var/lock lock file exists
# 3 program is not running
# 4 program or service status is unknown
# 5-99 reserved for future LSB use
# 100-149 reserved for distribution use
# 150-199 reserved for application use
# 200-254 reserved
function pidofproc {
local pidfile=""
local program=""
local pid=""
local pidlist=""
local list=""
local exitstatus=0
# Process arguments
while [[ $# -gt 0 ]]; do
case "${1}" in
-p) shift; pidfile="${1}" ;;
*) program="${1##*/}" ;;
esac
shift
done
# If a PID file is not specified, make one
test -z "${pidfile}" && pidfile="/var/run/${program}.pid"
# If a pid file exists and is readable, use it.
if [[ -r "${pidfile}" ]]; then
list=$(head -n1 "${pidfile}")
else
list=$(pidof "${program}")
exitstatus=$?
if [[ ${exitstatus} -gt 0 ]]; then exitstatus=4; fi
fi
if [[ exitstatus -eq 0 ]]; then
# Figure out if all listed PIDs are running.
for pid in ${list}; do
if kill -0 "${pid}" 2> /dev/null; then
pidlist+="${pid} "
else
exitstatus=1
fi
done
fi
if [[ -z "${pidlist}" ]]; then
if [[ -f "${pidfile}" ]]; then
exitstatus=1
else
exitstatus=3
fi
fi
printf "%s" "${pidlist% }"
return ${exitstatus}
}
Testing Function: pidofproc: Start
Testing pidofproc: valid program, no pidfile: running
Returns pid and exit status of 0
pidofproc /usr/sbin/dhcpcd: ---->:pid:[472] exit status:[0]
pidofproc dhcpcd: ---->:pid:[472] exit status:[0]
Testing pidofproc: valid program, valid pidfile: running
Returns pid and exit status of 0
pidofproc -p /var/run/dhcpcd.pid /usr/sbin/dhcpcd: ---->:pid:[472]
exit status:[0]
pidofproc /usr/sbin/dhcpcd -p /var/run/dhcpcd.pid: ---->:pid:[472]
exit status:[0]
pidofproc -p /var/run/dhcpcd.pid dhcpcd: ---->:pid:[472] exit
status:[0]
pidofproc dhcpcd -p /var/run/dhcpcd.pid: ---->: pid:[472] exit
status:[0]
Testing pidofproc: invalid program, no pidfile
Returns no pid and exit status of 3
pidofproc /usr/sbin/barf: ---->: pid:[] exit status:[3]
Testing pidofproc: valid program, invalid pidfile: running
Returns pid and exit status of 0
pidofproc -p barf.pid /usr/sbin/dhcpcd: ---->: pid:[472] exit
status:[0]
pidofproc /usr/sbin/dhcpcd -p barf.pid: ---->: pid:[472] exit
status:[0]
Testing pidofproc: valid program, no pidfile: not running
Returns no pid and exit status of 3
pidofproc /bin/ls: ---->: pid:[] exit status:[3]
Testing pidofproc: valid program: valid pidfile: not running
Returns no pid and exit status of 1
touch /var/run/ls.pid
pidofproc /bin/ls: ---->: pid:[] exit status:[1]
pidofproc -p /var/run/ls.pid /bin/ls: ---->: pid:[] exit status:[1]
rm /var/run/ls.pid
Looks great, tested it successfully with bash. Testing with busybox ash
does not work, but naturally, this is not needed on an LFS system.
I do have one question however:
Testing with invalid program and valid pidfile results in printing the
pid and returning 0:
Test with vaild program and valid pidfile:
root@keegan:~# ./pidofproc -p /var/run/dhcpcd-eno1.pid /sbin/dhcpcd
3144root@keegan:~# echo $?
0
root@keegan:~# ./pidofproc -p /var/run/dhcpcd-eno1.pid /sbin/dhcpcf
3144root@keeganecho $?
0
In the second case, /sbin/dhcpcf does not exist, but the pidfile does,
and belongs to /sbin/dhcpcd. Is this intended behaviour? Not that this
really matters a lot in real-world, as the function certainly will not
be called that way often.
Another minor question: What is the difference between
if [[ -r "${pidfile}" ]]; then
and
if [ -r "${pidfile}" ]; then
I always use the latter, you seem to prefer the first, is there a
difference I'm unaware of?
Bye
Tim
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