Strange Errno::EOVERFLOW error with IO#read and IO#sysread

Ruby
1

Hi all,

Ruby 1.8.6 p114 (32-bit)
Solaris 10

I’m reading binary data out of the /proc//as file on Solaris, and
I’m hitting a curious overflow error on one process in particular:

With IO#sysread

irb(main):010:0> File.open("/proc/383/as"){ |fh| fh.sysread(4) }
Errno::EOVERFLOW: Value too large for defined data type - /proc/383/as
from (irb):10:in sysread' from (irb):10 from (irb):10:inopen’
from (irb):10

With IO#read

rb(main):010:0> File.open("/proc/383/as"){ |fh| fh.read(4) }
Errno::EOVERFLOW: Value too large for defined data type - /proc/383/as
from (irb):10:in read' from (irb):10 from (irb):10:inopen’
from (irb):10

Where pid 383 is:

UID PID PPID C STIME TTY TIME CMD
root 383 1 0 07:14:42 ? 0:01 /usr/sfw/sbin/snmpd

This is the only pid in particular where this error occurs (out of
about 80).

Any idea what’s happening here?

Thanks,

Dan

2

On Sep 12, 2008, at 10:48 AM, Daniel B. wrote:

Errno::EOVERFLOW: Value too large for defined data type - /proc/383/as
from (irb):10:in `open’
Any idea what’s happening here?

Thanks,

Dan

your programs are so powerful daniel - they’re overwhelming the
system! maybe if you re-write in perl the system will be able to
handle them.

:wink:

a @ http://codeforpeople.com/

3

On Sep 12, 2008, at 11:28 AM, Daniel B. wrote:

Regards,

Dan

/me kids

/dan needs more coffee :wink:

a @ http://codeforpeople.com/

4

On Sep 12, 11:11 am, “ara.t.howard” [email protected] wrote:

I’m hitting a curious overflow error on one process in particular:
rb(main):010:0> File.open(“/proc/383/as”){ |fh| fh.read(4) }

system! maybe if you re-write in perl the system will be able to
handle them.

Nope:

use strict;
use warnings;

my $file = “/proc/383/as”;

open(FH, $file) or die $!;

my $buf = “”;

Dies here with: Value too large for defined data type

read(FH, $buf, 4, 0) or die $!;

close(FH);

Regards,

Dan

5

On Sep 12, 12:36 pm, “ara.t.howard” [email protected] wrote:

Nope:

Dies here with: Value too large for defined data type

/dan needs more coffee :wink:
As far as I can gather it’s a 32-bit largefile issue. The short
version is that a 32-bit Ruby (or Perl, or Python) will simply not be
able to read that file. The same code using a 64-bit Ruby works fine.

Well, except the part where my io-extra library segfaults on IO.pread
in 64-bit mode, but nevermind that.

Regards,

Dan