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 also allows  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.

       --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 --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

AUTHOR

       Elliot Lee ⟨sopwith@redhat.com⟩
       Jindrich Novy ⟨jnovy@redhat.com⟩
       Karel Zak ⟨kzak@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/⟩.