/ 
Linux-Personality-0.01
River stage zero No dependents
/ Linux::Personality

NAME

Linux::Personality - Perl interface to the personality(2) Linux system call.

SYNOPSIS

Common usage:

use Linux::Personality qw/personality PER_LINUX32 /;
print `uname -m`;                  # x86_64
personality(PER_LINUX32);
print `uname -m`;                  # i686

Use flags for bugs emulation:

use Linux::Personality qw/personality
                          PER_LINUX32
                          ADDR_LIMIT_3GB
                          SHORT_INODE
                          MMAP_PAGE_ZERO /;
personality(PER_LINUX32 | ADDR_LIMIT_3GB | SHORT_INODE | MMAP_PAGE_ZERO);

DESCRIPTION

You can use this for instance when running 32bit compiles started from inside a Perl program in a 32bit chroot but running on a 64bit host kernel. Without hints the compile tools get confused and try do do 64bit in the 32bit environment.

It's somewhat comparable to the setarch (also known as linux32) utility. With personality you can get similar effect inside a Perl program.

From "man 2 personality":

NAME
       personality - set the process execution domain

SYNOPSIS
       #include <sys/personality.h>
       int personality(unsigned long persona);

DESCRIPTION
       Linux supports different execution domains, or personalities,
       for each process.  Among other things, execution domains tell
       Linux how to map signal numbers into signal actions.  The
       execution domain system allows Linux to provide limited
       support for binaries compiled under other Unix-like operating
       systems.

       This function will return the current personality() when
       persona equals 0xffffffff.  Otherwise, it will make the
       execution domain referenced by persona the new execution
       domain of the calling process.

RETURN VALUE
       On success, the previous persona is returned.  On error, -1 is
       returned, and errno is set appropriately.

ERRORS
       EINVAL The kernel was unable to change the personality.

CONFORMING TO
       personality() is Linux-specific and should not be used in
       programs intended to be portable.

EXPORT

None by default.

Exportable functions

personality

Exportable constants

ADDR_LIMIT_32BIT
ADDR_LIMIT_3GB
ADDR_NO_RANDOMIZE
MMAP_PAGE_ZERO
PER_BSD
PER_HPUX
PER_IRIX32
PER_IRIX64
PER_IRIXN32
PER_ISCR4
PER_LINUX
PER_LINUX32
PER_LINUX32_3GB
PER_LINUX_32BIT
PER_MASK
PER_OSF4
PER_OSR5
PER_RISCOS
PER_SCOSVR3
PER_SOLARIS
PER_SUNOS
PER_SVR3
PER_SVR4
PER_UW7
PER_WYSEV386
PER_XENIX
SHORT_INODE
STICKY_TIMEOUTS
WHOLE_SECONDS

SEE ALSO

man 2 personality
/usr/include/sys/personality.h

AUTHOR

Steffen Schwigon, <ss5@renormalist.net>

CREDITS

Maik Hentsche <maik.hentsche@amd.com> for having the problem in the first place and digging the according solution.

Florian Ragwitz <rafl@debian.org> for the usual Perl low-level support.

COPYRIGHT AND LICENSE

Copyright (C) 2010 by Steffen Schwigon

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.10.1 or, at your option, any later version of Perl 5 you may have available.