Network status change notification in mac os x - macos

In Mac Os X how my application get informed when the status of network connection changes? I tried using SCNetworkConnectionGetStatus from SCNetworkConnection Reference. But it has to be called continuously. I need an API which will will inform me as soon as network status chages.

This is what I ended up using. Once I had this script I just put it into a basic while loop and voila -- network connectivity change monitoring.
#!/bin/bash
set -o pipefail
configured_ip_addresses="$((ifconfig | \
grep -iEo '[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+' | \
grep -vi '127.0.0.1' | tr '\n' ' ') || echo NONE_CONFIGURED)"
externally_visible_ip_address="$(curl -m 1 ipinfo.io/ip 2>/dev/null || echo NO_CONNECTIVITY)"
computed_state="Actual: $externally_visible_ip_address, Configured: $configured_ip_addresses"
statefile="/tmp/net-watcher.state"
if [ -f $statefile ]; then
echo "$computed_state" > "${statefile}-new"
new_chksum="$(md5 "${statefile}-new" | awk '{print $NF}')"
existing_chksum="$(md5 "${statefile}" | awk '{print $NF}')"
if [[ "${new_chksum}" != "${existing_chksum}" ]]; then
mv "${statefile}-new" "${statefile}"
osascript -e "display notification \"$(cat $statefile)\" with title \"ALERT: Network Changed\""
else
rm "${statefile}-new"
fi
else
echo "$computed_state" > $statefile
fi

Related

how to stop script from running when drives are full

I have a script that will run and fill up a drive without remorse. I want to set a highwater mark of 90%.
I created a cron that will check if the script is installed and if so if running.
#!/bin/sh
COUNTER=$(df -Ph | grep -vE '^tmpfs|cdrom' | sed s/%//g | sed 1d | awk '{ if($5 > 90) print $1;}' | wc -l)
if [[ -e /var/stats/automation/stats-collection.pl ]]; then
_running=$(ps faux | grep stats-collection.pl | grep -v grep | awk '{print $2}')
if [[ $_running -eq 1 ]]; then
echo "Stats running"
if [[ $COUNTER -gr 0 ]]; then
echo "Drive found above highwater mark. Ending Platform stats."
kill $_running
fi
else
echo "Platform stats not running."
else
echo "Platform stats not found"
fi
How would I combine the benefits of a continuously running cron job to run and stop the offending script from running. Would a while loop be the answer?

DD-WRT Bash script at startup issue

Hey all I have the following BASH script running at startup on my WRT1900ac linksys:
USER="admin"
PASS="passhere"
PROTOCOL="http"
ROUTER_IP="192.168.1.1"
# Port to connect to which will provide the JSON data.
PORT=9898
while [ 1 ]
do
# Grab connected device MAC addresses through router status page.
MACS=$(curl -s --user $USER:$PASS $PROTOCOL://$ROUTER_IP/Status_Wireless.live.asp)
# clear temp JSON file
echo > temp.log
# Get hostname and IP (just in case there is no hostname).
for MAC in $(echo $MACS | grep -oE "wl_mac::[a-z0-9]{2}:[a-z0-9]{2}:[a-z0-9]{2}:[a-z0-9]{2}:[a-z0-9]{2}:[a-z0-9]{2}" | cut -c 9-);
do
grep 0x /proc/net/arp | awk '{print $1 " " $4}' | while IFS= read -r line
do
IP=$(echo $line | cut -d' ' -f1)
MACTEMP=$(echo $line | cut -d' ' -f2)
HOST=$(arp -a | grep $IP | cut -d' ' -f1)
# if no hostname exists, just use IP.
if [ "$HOST" == "" ]
then
HOST=$IP
fi
if [ "$MAC" == "$MACTEMP" ]
then
JSON="{'hostname' : '$HOST', 'mac_address' : '$MAC'}"
echo $JSON >> temp.log
fi
done
done
# Provide the JSON formatted output on $PORT of router.
# This allows one connection before closing the port (connect, receive data, close).
# Port will reopen every 5 minutes with new data as setup in a cron job.
echo -e "HTTP/1.1 200 OK\n\n $(cat temp.log)" | nc -l -p$PORT >/dev/null
# Wait for 10 seconds and do it all over.
sleep 10
done
And for some reason when I reboot the router and then try to visit http://192.168.1.1:9898 it just shows a blank page even though I have my android cell phone connected via wifi to the router and the router shows the MAC address on the status page.
What should be on that page is all the wireless MAC address that are currently connected to the router and displaying them out in JSON form.
Any BASH guru's here that can help spot the problem?
I think it should be
echo -e "HTTP/1.1 200 OK\n\n $(cat temp.log)" | nc -l -p$PORT 0.0.0.0 >/dev/null

Issue with Script

We have a script which is checking and sending an alert if process goes down. For some reason it is not capturing it properly for all the users and not sending the alerts in all scenarios.
Please suggest what could be the problem.
Environments – uatwrk1, uatwrk2, uatwrk3 ------- uatwrk100
ServerName - myuatserver
Process to be checked - Amc/apache/bin/httpd
Script is :
#!/bin/ksh
i=1
while (( i<=100 ))
do
myuser=uatwrk$i
NoOfProcess=`ps -ef | grep -v grep | grep $myuser | grep "Amc/apache/bin/httpd" | wc -l`
if [[ $NoOfProcess -eq 0 ]]
then
echo "Amc process is down, sending an alert"
# Assume sendAlert.ksh is fine
./sendAlert.ksh
else
echo "Amc process is running fine" >> /dev/null
fi
(( i+=1 ))
done
I think #Mahesh already indicated the problem in a comment.
When you only want to have a mail once, you can count the users running a httpd process. The backslash in the following command is for avoiding grep -v grep.
ps -ef | grep "A\mc/apache/bin/httpd" | cut -d " " -f1 | grep "^uatwrk"| sort -u | wc -l

A script to find all the users who are executing a specific program

I've written the bash script (searchuser) which should display all the users who are executing a specific program or a script (at least a bash script). But when searching for scripts fails because the command the SO is executing is something like bash scriptname.
This script acts parsing the ps command output, it search for all the occurrences of the specified program name, extracts the user and the program name, verifies if the program name is that we're searching for and if it's it displays the relevant information (in this case the user name and the program name, might be better to output also the PID, but that is quite simple). The verification is accomplished to reject all lines containing program names which contain the name of the program but they're not the program we are searching for; if we're searching gedit we don't desire to find sgedit or gedits.
Other issues I've are:
I would like to avoid the use of a tmp file.
I would like to be not tied to GNU extensions.
The script has to be executed as:
root# searchuser programname <invio>
The script searchuser is the following:
#!/bin/bash
i=0
search=$1
tmp=`mktemp`
ps -aux | tr -s ' ' | grep "$search" > $tmp
while read fileline
do
user=`echo "$fileline" | cut -f1 -d' '`
prg=`echo "$fileline" | cut -f11 -d' '`
prg=`basename "$prg"`
if [ "$prg" = "$search" ]; then
echo "$user - $prg"
i=`expr $i + 1`
fi
done < $tmp
if [ $i = 0 ]; then
echo "No users are executing $search"
fi
rm $tmp
exit $i
Have you suggestion about to solve these issues?
One approach might looks like such:
IFS=$'\n' read -r -d '' -a pids < <(pgrep -x -- "$1"; printf '\0')
if (( ! ${#pids[#]} )); then
echo "No users are executing $1"
fi
for pid in "${pids[#]}"; do
# build a more accurate command line than the one ps emits
args=( )
while IFS= read -r -d '' arg; do
args+=( "$arg" )
done </proc/"$pid"/cmdline
(( ${#args[#]} )) || continue # exited while we were running
printf -v cmdline_str '%q ' "${args[#]}"
user=$(stat --format=%U /proc/"$pid") || continue # exited while we were running
printf '%q - %s\n' "$user" "${cmdline_str% }"
done
Unlike the output from ps, which doesn't distinguish between ./command "some argument" and ./command "some" "argument", this will emit output which correctly shows the arguments run by each user, with quoting which will re-run the given command correctly.
What about:
ps -e -o user,comm | egrep "^[^ ]+ +$1$" | cut -d' ' -f1 | sort -u
* Addendum *
This statement:
ps -e -o user,pid,comm | egrep "^\s*\S+\s+\S+\s*$1$" | while read a b; do echo $a; done | sort | uniq -c
or this one:
ps -e -o user,pid,comm | egrep "^\s*\S+\s+\S+\s*sleep$" | xargs -L1 echo | cut -d ' ' -f1 | sort | uniq -c
shows the number of process instances by user.

Bash script checking cpu usage of specific process

First off, I'm new to this. I have some experience with windows scripting and apple script but not much with bash. What I'm trying to do is grab the PID and %CPU of a specific process. then compare the %CPU against a set number, and if it's higher, kill the process. I feel like I'm close, but now I'm getting the following error:
[[: 0.0: syntax error: invalid arithmetic operator (error token is ".0")
what am I doing wrong? here's my code so far:
#!/bin/bash
declare -i app_pid
declare -i app_cpu
declare -i cpu_limit
app_name="top"
cpu_limit="50"
app_pid=`ps aux | grep $app_name | grep -v grep | awk {'print $2'}`
app_cpu=`ps aux | grep $app_name | grep -v grep | awk {'print $3'}`
if [[ ! $app_cpu -gt $cpu_limit ]]; then
echo "crap"
else
echo "we're good"
fi
Obviously I'm going to replace the echos in the if/then statement but it's acting as if the statement is true regardless of what the cpu load actually is (I tested this by changing the -gt to -lt and it still echoed "crap"
Thank you for all the help. Oh, and this is on a OS X 10.7 if that is important.
I recommend taking a look at the facilities of ps to avoid multiple horrible things you do.
On my system (ps from procps on linux, GNU awk) I would do this:
ps -C "$app-name" -o pid=,pcpu= |
awk --assign maxcpu="$cpu_limit" '$2>maxcpu {print "crappy pid",$1}'
The problem is that bash can't handle decimals. You can just multiply them by 100 and work with plain integers instead:
#!/bin/bash
declare -i app_pid
declare -i app_cpu
declare -i cpu_limit
app_name="top"
cpu_limit="5000"
app_pid=`ps aux | grep $app_name | grep -v grep | awk {'print $2'}`
app_cpu=`ps aux | grep $app_name | grep -v grep | awk {'print $3*100'}`
if [[ $app_cpu -gt $cpu_limit ]]; then
echo "crap"
else
echo "we're good"
fi
Keep in mind that CPU percentage is a suboptimal measurement of application health. If you have two processes running infinite loops on a single core system, no other application of the same priority will ever go over 33%, even if they're trashing around.
#!/bin/sh
PROCESS="java"
PID=`pgrep $PROCESS | tail -n 1`
CPU=`top -b -p $PID -n 1 | tail -n 1 | awk '{print $9}'`
echo $CPU
I came up with this, using top and bc.
Use it by passing in ex: ./script apache2 50 # max 50%
If there are many PIDs matching your program argument, only one will be calculated, based on how top lists them. I could have extended the script by catching them all and avergaing the percentage or something, but this will have to do.
You can also pass in a number, ./script.sh 12345 50, which will force it to use an exact PID.
#!/bin/bash
# 1: ['command\ name' or PID number(,s)] 2: MAX_CPU_PERCENT
[[ $# -ne 2 ]] && exit 1
PID_NAMES=$1
# get all PIDS as nn,nn,nn
if [[ ! "$PID_NAMES" =~ ^[0-9,]+$ ]] ; then
PIDS=$(pgrep -d ',' -x $PID_NAMES)
else
PIDS=$PID_NAMES
fi
# echo "$PIDS $MAX_CPU"
MAX_CPU="$2"
MAX_CPU="$(echo "($MAX_CPU+0.5)/1" | bc)"
LOOP=1
while [[ $LOOP -eq 1 ]] ; do
sleep 0.3s
# Depending on your 'top' version and OS you might have
# to change head and tail line-numbers
LINE="$(top -b -d 0 -n 1 -p $PIDS | head -n 8 \
| tail -n 1 | sed -r 's/[ ]+/,/g' | \
sed -r 's/^\,|\,$//')"
# If multiple processes in $PIDS, $LINE will only match\
# the most active process
CURR_PID=$(echo "$LINE" | cut -d ',' -f 1)
# calculate cpu limits
CURR_CPU_FLOAT=$(echo "$LINE"| cut -d ',' -f 9)
CURR_CPU=$(echo "($CURR_CPU_FLOAT+0.5)/1" | bc)
echo "PID $CURR_PID: $CURR_CPU""%"
if [[ $CURR_CPU -ge $MAX_CPU ]] ; then
echo "PID $CURR_PID ($PID_NAMES) went over $MAX_CPU""%"
echo "[[ $CURR_CPU""% -ge $MAX_CPU""% ]]"
LOOP=0
break
fi
done
echo "Stopped"
Erik, I used a modified version of your code to create a new script that does something similar. Hope you don't mind it.
A bash script to get the CPU usage by process
usage:
nohup ./check_proc bwengine 70 &
bwegnine is the process name we want to monitor 70 is to log only when the process is using over 70% of the CPU.
Check the logs at: /var/log/check_procs.log
The output should be like:
DATE | TOTAL CPU | CPU USAGE | Process details
Example:
03/12/14 17:11 |20.99|98| ProdPROXY-ProdProxyPA.tra
03/12/14 17:11 |20.99|100| ProdPROXY-ProdProxyPA.tra
Link to the full blog:
http://felipeferreira.net/?p=1453
It is also useful to have app_user information available to test whether the current user has the rights to kill/modify the running process. This information can be obtained along with the needed app_pid and app_cpu by using read eliminating the need for awk or any other 3rd party parser:
read app_user app_pid tmp_cpu stuff <<< \
$( ps aux | grep "$app_name" | grep -v "grep\|defunct\|${0##*/}" )
You can then get your app_cpu * 100 with:
app_cpu=$((${tmp_cpu%.*} * 100))
Note: Including defunct and ${0##*/} in grep -v prevents against multiple processes matching $app_name.
I use top to check some details. It provides a few more details like CPU time.
On Linux this would be:
top -b -n 1 | grep $app_name
On Mac, with its BSD version of top:
top -l 1 | grep $app_name

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