问并行平扫

EN

#!/bin/bash
ping() {
  if ping -c 1 -W 5 131.212.$i.$j >/dev/null
  then
      ((++s))
      echo -n "*"
  else
      ((++f))
      echo -n "."
  fi
  ((++j))
  #if j has reached 255, set it to zero and increment i
  if [ $j -gt 255 ]; then
      j=0
      ((++i))
      echo "Pinging 131.212.$i.xx IP Block...\n"
  fi
}

s=0 #number of responses recieved
f=0 #number of failures recieved
i=0 #IP increment 1
j=0 #IP increment 2
curProcs=$(ps | wc -l)
maxProcs=$(getconf OPEN_MAX)
while [ $i -lt 256 ]; do
    curProcs=$(ps | wc -l)
    if [ $curProcs -lt $maxProcs ]; then
      ping &
    else
      sleep 10
    fi
done
echo "Found "$s" responses and "$f" timeouts."
echo /usr/bin/time -l
done

redirection error: cannot duplicate fd: Too many open files

#!/bin/bash

#############################
#      Ping Subfunction     #
#############################
# blocks with more responses will complete first since worst-case scenerio
# is O(n) if no IPs generate a response
pingSubnet() {
  for ((j = 0 ; j <= 255 ; j++)); do
    # send a single ping with a timeout of 5 sec, piping output to the bitbucket
    if ping -c 1 -W 1 131.212."$i"."$j" >/dev/null
    then
        ((++s))
    else
        ((++f))
    fi
  done
  #echo "Recieved $s responses with $f timeouts in block $i..."
  # output number of success results to the pipe opened in at the start
  echo "$s" >"$pipe"
  exit 0
}

#############################
#   Variable Declaration    #
#############################
start=$(date +%s) #start of execution time
startMem=$(vm_stat | awk '/Pages free/ {print $3}' | awk 'BEGIN { FS = "\." }; {print ($1*0.004092)}' | sed 's/\..*$//');
startCPU=$(top -l 1 | grep "CPU usage" | awk '{print 100-$7;}' | sed 's/\..*$//')
s=0 #number of responses recieved
f=0 #number of failures recieved
i=0 #IP increment 1
j=0 #IP increment 2

#############################
#    Pipe Initialization    #
#############################
# create a pipe for child procs to write to
# child procs inherit runtime environment of parent proc, but cannot
# write back to it (like passing by value in C, but the whole env)
# hence, they need somewhere else to write back to that the parent
# proc can read back in
pipe=/tmp/pingpipe
trap 'rm -f $pipe' EXIT
if [[ ! -p $pipe ]]; then
    mkfifo $pipe
    exec 3<> $pipe
fi

#############################
#     IP Block Iteration    #
#############################
# adding an ampersand to the end forks the command to a separate, backgrounded
# child process. this allows for parellel computation but adds logistical
# challenges since children can't write the parent's variables
echo "Initiating scan processes..."
while [ $i -lt 256 ]; do
      #echo "Beginning 131.212.$i.x block scan..."
      #ping subnet asynchronously
      pingSubnet &
      ((++i))
done
echo "Waiting for scans to complete (this may take up to 5 minutes)..."
peakMem=$(vm_stat | awk '/Pages free/ {print $3}' | awk 'BEGIN { FS = "\." }; {print ($1*0.004092)}' | sed 's/\..*$//')
peakCPU=$(top -l 1 | grep "CPU usage" | awk '{print 100-$7;}' | sed 's/\..*$//')
wait
echo -e "done" >$pipe

#############################
#    Concat Pipe Outputs    #
#############################
# read each line from the pipe we created earlier, adding the number
# of successes up in a variable
success=0
echo "Tallying responses..."
while read -r line <$pipe; do
    if [[ "$line" == 'done' ]]; then
      break
    fi
    success=$((line+success))
done

#############################
#    Output Statistics      #
#############################
echo "Gathering Statistics..."
fail=$((65535-success))
#output program statistics
averageMem=$((peakMem-startMem))
averageCPU=$((peakCPU-startCPU))
end=$(date +%s) #end of execution time
runtime=$((end-start))
echo "Scan completed in $runtime seconds."
echo "Found $success active servers and $fail nonresponsive addresses with a timeout of 1."
echo "Estimated memory usage was $averageMem MB."
echo "Estimated CPU utilization was $averageCPU %"