SETARCH(8)		     System Administration		    SETARCH(8)

NAME
       setarch - change reported architecture in new program environment
       and/or set personality flags

SYNOPSIS
       setarch [arch] [options] [program [argument...]]

       setarch --list|-h|-V

       arch [options] [program [argument...]]

DESCRIPTION
       setarch modifies execution domains and process personality flags.

       The execution domains currently only affects the output of uname -m.
       For example, on an AMD64 system, running setarch i386 program will
       cause program to see i686 instead of x86_64 as the machine type. It can
       also be used to set various personality options. The default program is
       /bin/sh.

       Since version 2.33 the arch command line argument is optional and
       setarch may be used to change personality flags (ADDR_LIMIT_*,
       SHORT_INODE, etc) without modification of the execution domain.

OPTIONS
       --list
	   List the architectures that setarch knows about. Whether setarch
	   can actually set each of these architectures depends on the running
	   kernel.

       --show[=personality]
	   Show the currently active personality and flags.  If the
	   personality argument is provided, it is shown instead of the
	   current one.	 personality is a hexadecimal number with values was
	   described in sys/personality.h.

       --uname-2.6
	   Causes the program to see a kernel version number beginning with
	   2.6. Turns on UNAME26.

       -v, --verbose
	   Be verbose.

       -3, --3gb
	   Specifies program should use a maximum of 3GB of address space.
	   Supported on x86. Turns on ADDR_LIMIT_3GB.

       --4gb
	   This option has no effect. It is retained for backward
	   compatibility only, and may be removed in future releases.

       -B, --32bit
	   Limit the address space to 32 bits to emulate hardware. Supported
	   on ARM and Alpha. Turns on ADDR_LIMIT_32BIT.

       -F, --fdpic-funcptrs
	   Treat user-space function pointers to signal handlers as pointers
	   to address descriptors. This option has no effect on architectures
	   that do not support FDPIC ELF binaries. In kernel v4.14 support is
	   limited to ARM, Blackfin, Fujitsu FR-V, and SuperH CPU
	   architectures.

       -I, --short-inode
	   Obsolete bug emulation flag. Turns on SHORT_INODE.

       -L, --addr-compat-layout
	   Provide legacy virtual address space layout. Use when the program
	   binary does not have PT_GNU_STACK ELF header. Turns on
	   ADDR_COMPAT_LAYOUT.

       -R, --addr-no-randomize
	   Disables randomization of the virtual address space. Turns on
	   ADDR_NO_RANDOMIZE.

       -S, --whole-seconds
	   Obsolete bug emulation flag. Turns on WHOLE_SECONDS.

       -T, --sticky-timeouts
	   This makes select(2), pselect(2), and ppoll(2) system calls
	   preserve the timeout value instead of modifying it to reflect the
	   amount of time not slept when interrupted by a signal handler. Use
	   when program depends on this behavior. For more details see the
	   timeout description in select(2) manual page. Turns on
	   STICKY_TIMEOUTS.

       -X, --read-implies-exec
	   If this is set then mmap(2) PROT_READ will also add the PROT_EXEC
	   bit - as expected by legacy x86 binaries. Notice that the ELF
	   loader will automatically set this bit when it encounters a legacy
	   binary. Turns on READ_IMPLIES_EXEC.

       -Z, --mmap-page-zero
	   SVr4 bug emulation that will set mmap(2) page zero as read-only.
	   Use when program depends on this behavior, and the source code is
	   not available to be fixed. Turns on MMAP_PAGE_ZERO.

       -h, --help
	   Display help text and exit.

       -V, --version
	   Display version and exit.

EXAMPLE
	   setarch --addr-no-randomize mytestprog
	   setarch ppc32 rpmbuild --target=ppc --rebuild foo.src.rpm
	   setarch ppc32 -v -vL3 rpmbuild --target=ppc --rebuild bar.src.rpm
	   setarch ppc32 --32bit rpmbuild --target=ppc --rebuild foo.src.rpm

AUTHORS
       Elliot Lee <sopwith@redhat.com>, Jindrich Novy <jnovy@redhat.com>,
       Karel Zak <kzak@redhat.com>

SEE ALSO
       personality(2), select(2)

REPORTING BUGS
       For bug reports, use the issue tracker
       <https://github.com/util-linux/util-linux/issues>.

AVAILABILITY
       The setarch command is part of the util-linux package which can be
       downloaded from Linux Kernel Archive
       <https://www.kernel.org/pub/linux/utils/util-linux/>.

util-linux 2.41.2		  2025-09-22			    SETARCH(8)