Killing a process that takes too long

Shell Programming and Scripting
1

Hello,
I have a C program that takes anywhere from 5 to 100 arguments and I'd like to run it from a script that makes sure it doesnt take too long to execute. If the C program takes more than 5 seconds to execute, i would like the shell script to kill it and return a short message to the user. If it takes less than 5 seconds, the program spits out a short message to standard out, then i'd like the script to stop normally.

Can a script help do this?, or am I going to have to rewrite the C program to handle this?

The problem is, it seems like i would need a multi-threaded shell script?...I'm really not sure how to go about doing this. Any help would be greatly appreciated. I'm running bash 3.00.15 on redhat.

Thanks

2

Try this if you don't want to change your c program

#!/usr/bin/perl -w

my $timeout = 5; # 5 sec timeout

eval {
local $SIG{ALRM} = sub { die "alarm\n" };
alarm $timeout;
qx(./mah.ksh);
alarm 0;
};

if ($@) {
die unless $@ eq "alarm\n";
print "timeout\n";
qx(ps -ef | grep mah.ksh | egrep -v " grep | vi | more | cat | pg | egrep " | awk '{print \$2}' | xargs kill );
}
else {
print "no timeout \n";
}

replace mah.ksh with your c program name.

3

Thanks...that script works great :slight_smile:

Although I'm still having problems...I modified your perl script to be able to take command line arguments...is there a faster way than the way I did it?

The main problem however is that whenever I have php4's shell_exec command calling this script, nothing that is printed via perl's qx command gets returned to php4...i tried 'system($command)' rather than 'qx($command)', but that doesn't help...interestingly though, 'print system($command)' returns a -1 to php, but from a terminal, all of those run the program as desired...

how can i get shell_exec to see output from a call to qx?...is qx opening a new stream each time it is called or something?

here's my perl modified script:

#!/usr/bin/perl -w

# Run my_program w/ the given arguments.  If my_program is still running 
# after the specified number of seconds, kill it, and tell the user.

my $timeout = 5; # 5 second timeout

eval {
  local $SIG{ALRM} = sub { die "alarm\n" };
  alarm $timeout;
  $command = "./my_program";
  foreach $argnum (0 .. $#ARGV) {
    $command .= " $ARGV[$argnum]";
  }
  print qx($command);
  alarm 0;
};

if($@){
  die unless $@ eq "alarm\n";
  print "timeout\n";
  qx(ps -ef | grep pokenum | egrep -v " grep | vi | more | cat | pg | egrep " | awk '{print \$2}' | xargs kill );
}
4

just assign it to some variable.... and then print

my $xyz = qx(unix command);
print $xyz,"\n";