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/⟩.