How do I change the process name? - linux

Question

Does anyone know how to change the process name in top?
top - 05:02:47 up 182 days, 10:38, 1 user, load average: 14.53, 13.11, 11.95
Tasks: 4 total, 2 running, 2 sleeping, 0 stopped, 0 zombie
Cpu(s): 57.2%us, 14.8%sy, 0.0%ni, 26.2%id, 1.3%wa, 0.0%hi, 0.5%si, 0.0%st
Mem: 24736852k total, 22519688k used, 2217164k free, 132268k buffers
Swap: 8386552k total, 741900k used, 7644652k free, 12416224k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
6230 user 20 0 47540 6856 1164 R 41.5 0.0 0:03.10 perl
6430 user 20 0 14900 1156 936 R 0.3 0.0 0:00.02 top
6227 user 20 0 47276 7552 2088 S 0.0 0.0 0:00.07 perl
14577 user 20 0 11588 1808 1340 S 0.0 0.0 0:00.46 bash
I have figured out how to change the top -c name
$0 = 'new name.';
However this doesn't accomplish my goal.
I found a non standard module, and it looks very promising,
However I can't use any non standard modules.
http://metacpan.org/pod/Sys::Prctl
# instead of "perl helloworld.pl"
$0 = "helloworld"
prctl_name("helloworld");
I was hoping someone had some input, or knowledge on changing the title/name of a process.
I feel I have gone through perlvar pretty thoroughly however I may have missed a simple $^0. Hoping it's that simple.
Edit
#user2783897, not sure why I didn't think of that, here is the basic example I made.
sub prctl_name {
my $TASK_COMM_LEN = 16;
my $SYS_prctl = 157;
my $SYS_PR_SET_NAME = 15;
my $SYS_PR_GET_NAME = 16;
my ($str) = #_;
if(defined $str) {
my $rv = prctl($SYS_PR_SET_NAME, $str);
if($rv == 0) {
return 1;
} else {
return;
}
} else {
$str = "\x00" x ($TASK_COMM_LEN + 1); # allocate $str
my $ptr = unpack( 'L', pack( 'P', $str ) );
my $rv = prctl($SYS_PR_GET_NAME, $ptr);
if($rv == 0) {
return substr($str, 0, index($str, "\x00"));
} else {
return;
}
}
}
sub prctl {
my $SYS_prctl = 157;
my ($option, $arg2, $arg3, $arg4, $arg5) = #_;
syscall($SYS_prctl, $option,
($arg2 or 0), ($arg3 or 0), ($arg4 or 0), ($arg5 or 0));
}

Answer 1

Why don't you copy Sys/Prctl.pm code inside your own ? It's only a few dozens of lines.
Furthermore, most of the code is dedicated to finding on which kind of kernel the process is running, to select the appropriate SYS_prctl parameter. If you know on what kind of kernel you're running, you can cut the code to its bare bone.