perl/linux ulimit -f question
Hello monks. I'm trying to capture an error if i run out of disk space. To test this (I've never done anything like this before) I have started a new shell (bash) and ran ulimit -f 10. I then wrote a dummy program (called lots_of_print.pl) to try and capture the error and print to stderr. However I'm not getting my program's error message but I'm getting a message from the OS or maybe from the perl interpreter (so I can tell ulimit worked). Any ideas what I'm doing wrong? Thanks for your help,
Erik
here is my shell output
here is my program
Most Linux systems have a /dev/full device that you can use for testing disk full scenarios.
All dogma is stupid.
here is my shell output
[egartz@localhost fullment_programs]$ ulimit -f 10 [egartz@localhost fullment_programs]$ ./lots_of_print.pl File size limit exceeded [egartz@localhost fullment_programs]$
here is my program
#!/usr/local/bin/perl -w
use strict;
open (LARGE_FILE, ">large_file.txt");
for ( 1 .. 10000){
print LARGE_FILE "dummy line...dummy line...dummy line...dummy line...dummy line...dummy line...dummy line...\n" or print STDERR "i caught the error!\n";
}
Re: perl/linux ulimit -f question
created: 2006-04-03 09:31:49
When you exceed a limit (most of them, anyway), your program is immediately aborted. The shell notices this, and prints the message. There's no way your program could capture that message, as it has already been forcibly terminated.
-- Randal L. Schwartz, Perl hacker
Be sure to read my standard disclaimer if this is a reply.
Re: perl/linux ulimit -f question
created: 2006-04-03 09:48:48
Most Linux systems have a /dev/full device that you can use for testing disk full scenarios.
See the full manpage.
--
John.
Re: perl/linux ulimit -f question
created: 2006-04-03 09:56:29
Take a look at the manpage for setrlimit (which ulimit uses to implement it's functionality). On my system this says
RLIMIT_FSIZE
The maximum size of files that the process may create. Attempts to extend a file beyond this limit result in delivery of a SIGXFSZ signal. By default, this signal terminates a process, but a process can catch this signal instead, in which case the relevant system call (e.g., write(), truncate()) fails with the error EFBIG.
So in order to prevent your program from terminating you need to catch the SIGXFSZ signal, either by setting local $SIG{XFSZ}=IGNORE or by doing something more fancy, aka
local $SIG{XFSZ}=sub { print STDERR "Caught SIGXFSZ" };
All dogma is stupid.
Re^2: perl/linux ulimit -f question
created: 2006-04-03 14:07:46
thank you all for your help. i'm glad i'm now aware of /dev/full (it worked perfect for my testing). it seems like a good thing to be aware of for the future. regards,
erik