SETARCH(8)                  System Administration                 SETARCH(8)

NAME         top

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

SYNOPSIS         top

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

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

       setarch --list|-h|-V

DESCRIPTION         top

       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         top

       --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         top

       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         top

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

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 
       ⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩.

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 
       ⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩.  If you have a
       bug report for this manual page, send it to
       util-linux@vger.kernel.org.  This page was obtained from the
       project's upstream Git repository
       ⟨git://git.kernel.org/pub/scm/utils/util-linux/util-linux.git⟩ on
       2018-02-02.  (At that time, the date of the most recent commit that
       was found in the repository was 2018-02-01.)  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
       man-pages@man7.org

util-linux                      December 2017                     SETARCH(8)

Pages that refer to this page: personality(2)

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