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

              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(3p) 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

       -Z, --mmap-page-zero
              SVr4 bug emulation that will set mmap(3p) page zero as
              read-only.  Use when program depends on this behavior, and
              the source code is not available to be fixed.  Turns on

       -V, --version
              Display version information and exit.

       -h, --help
              Display help text 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)

AVAILABILITY         top

       The setarch command is part of the util-linux package and is
       available from Linux Kernel Archive 

COLOPHON         top

       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
       2021-03-21.  (At that time, the date of the most recent commit
       that was found in the repository was 2021-03-19.)  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                    December 2017                   SETARCH(8)

Pages that refer to this page: personality(2)