Manual: setarch

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 , Jindrich Novy , Karel Zak 

SEE ALSO
       personality(2), select(2)

REPORTING BUGS
       For bug reports, use the issue tracker .

AVAILABILITY
       The setarch command is part of the util-linux package which can be downloaded from Linux Kernel
       Archive .

util-linux 2.41.3				 2025-12-15					  SETARCH(8)