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 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

       --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(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 READ_IMPLIES_EXEC.

       -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
           MMAP_PAGE_ZERO.

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

       -V, --version
           Print version and exit.

EXAMPLE

           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

       Elliot Lee <sopwith@redhat.com>, Jindrich Novy <jnovy@redhat.com>, Karel Zak
       <kzak@redhat.com>

SEE ALSO

       personality(2), select(2)

REPORTING BUGS

       For bug reports, use the issue tracker at https://github.com/util-linux/util-linux/issues.

AVAILABILITY

       The setarch command is part of the util-linux package which can be downloaded from Linux
       Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.