setarch(8) — Linux manual page


SETARCH(8)                System Administration               SETARCH(8)

NAME         top

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

SYNOPSIS         top

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

       setarch --list|-h|-V

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

DESCRIPTION         top

       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         top

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

           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.

           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.

           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

       -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

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

       -V, --version
           Print version and exit.

EXAMPLE         top

           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         top

       Elliot Lee <>, Jindrich Novy
       <>, Karel Zak <>

SEE ALSO         top

       personality(2), select(2)

REPORTING BUGS         top

       For bug reports, use the issue tracker at

AVAILABILITY         top

       The setarch command is part of the util-linux package which can
       be downloaded from Linux Kernel Archive
       <>. This page
       is part of the util-linux (a random collection of Linux
       utilities) project. Information about the project can be found at
       ⟨⟩. If you have
       a bug report for this manual page, send it to This page was obtained from the
       project's upstream Git repository
       ⟨git://⟩ on
       2023-12-22. (At that time, the date of the most recent commit
       that was found in the repository was 2023-12-14.) If you discover
       any rendering problems in this HTML version of the page, or you
       believe there is a better or more up-to-date source for the page,
       or you have corrections or improvements to the information in
       this COLOPHON (which is not part of the original manual page),
       send a mail to

util-linux 2.39.594-1e0ad      2023-07-19                     SETARCH(8)

Pages that refer to this page: personality(2)