Remove (yad) unreleased shared memory blocks (Linux).

rm-yad-shmem.sh

#!/bin/sh

# rm-yad-shmem for yad 0.36.3 and possibly other versions.

# Motivation
#
# Some times, when you kill [-USR1/-USR2] a plugged dialog, or the paned/tabbed
# dialog that hosts the plugged dialog, its shared memory (shmem) may not be
# fully released. This tool aids in releasing shmem blocks interactively.

# Limitation
#
# As far as I know, telling which shmem blocks a defunct process owned isn't
# possible. So this tool can only help identifying unowned blocks, and you are
# left to decide whether those belonged to the killed yad or to something
# totally different.  There is nothing really specific to yad in this script.

# See also https://stackoverflow.com/a/5658711

NATTCH=0 # query
ipcs -m |
while read \
  key        shmid      owner      perms      bytes      nattch     status      
do

  if [ $NATTCH = "$nattch" ]; then
    printf "key %d (0x%x) shmid %d has %d attached processes\n" $key $key $shmid $nattch
    printf "%s is the owner\n" $owner
    ipcs -mp |
    while read \
      shmid2      owner2      cpid       lpid 
    do
      if [ $shmid = "$shmid2" ]; then
        printf "PID %d created %d and PID %d last attached to it\n" $cpid $shmid2 $lpid
        {
        ps --cols 9999 -ho pid,cmd $cpid 2>/dev/null
        grep $shmid2 /proc/$cpid/maps 2>/dev/null
        } || echo "PID $cpid is no longer running"
        {
        ps --cols 9999 -ho pid,cmd $lpid 2>/dev/null
        grep $shmid2 /proc/$lpid/maps 2>/dev/null
        } || echo "PID $lpid is no longer running"
        printf "Remove shmid %s ? (y/N) " $shmid2
        read reply < /dev/tty
        case $reply in y*|Y* ) ipcrm shm $shmid2;; esac
      fi
    done
  fi
done