NAME

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

SYNOPSIS

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

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

       setarch --list|-h|-V

DESCRIPTION

       setarch  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 also allows to set
       various personality options.  The default program is /bin/sh.

OPTIONS

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

       --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(3) 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(3) 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.

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

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

EXAMPLES

       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

AUTHOR

       Elliot Lee ⟨sopwith@redhat.com⟩
       Jindrich Novy ⟨jnovy@redhat.com⟩

SEE ALSO

       personality(2), select(2)

AVAILABILITY

       The setarch command is part of the  util-linux  package  and  is  available  from  Linux  Kernel  Archive
       ⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩.