1SETARCH(8)                   System Administration                  SETARCH(8)
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NAME

6       setarch  -  change  reported  architecture  in  new program environment
7       and/or set personality flags
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SYNOPSIS

10       setarch [arch] [options] [program [argument...]]
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12       setarch --list|-h|-V
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14       arch [options] [program [argument...]]
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DESCRIPTION

17       setarch modifies execution domains and process personality flags.
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19       The execution domains currently only affects the output  of  uname  -m.
20       For  example,  on  an  AMD64  system, running setarch i386 program will
21       cause program to see i686 instead of x86_64 as the  machine  type.   It
22       also allows to set various personality options.  The default program is
23       /bin/sh.
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25       Since version 2.33 the arch  command  line  argument  is  optional  and
26       setarch   may  be  used  to  change  personality  flags  (ADDR_LIMIT_*,
27       SHORT_INODE, etc) without modification of the execution domain.
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OPTIONS

30       --list List  the  architectures  that  setarch  knows  about.   Whether
31              setarch  can actually set each of these architectures depends on
32              the running kernel.
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34       --uname-2.6
35              Causes the program to see a kernel version number beginning with
36              2.6.  Turns on UNAME26.
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38       -v, --verbose
39              Be verbose.
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41       -3, --3gb
42              Specifies  program should use a maximum of 3GB of address space.
43              Supported on x86.  Turns on ADDR_LIMIT_3GB.
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45       --4gb  This option has no effect.  It is retained for backward compati‐
46              bility only, and may be removed in future releases.
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48       -B, --32bit
49              Limit  the  address  space to 32 bits to emulate hardware.  Sup‐
50              ported on ARM and Alpha.  Turns on ADDR_LIMIT_32BIT.
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52       -F, --fdpic-funcptrs
53              Treat user-space function pointers to signal handlers as  point‐
54              ers to address descriptors.  This option has no effect on archi‐
55              tectures that do not support  FDPIC  ELF  binaries.   In  kernel
56              v4.14  support  is  limited  to ARM, Blackfin, Fujitsu FR-V, and
57              SuperH CPU architectures.
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59       -I, --short-inode
60              Obsolete bug emulation flag.  Turns on SHORT_INODE.
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62       -L, --addr-compat-layout
63              Provide legacy virtual address space layout.  Use when the  pro‐
64              gram  binary  does  not  have PT_GNU_STACK ELF header.  Turns on
65              ADDR_COMPAT_LAYOUT.
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67       -R, --addr-no-randomize
68              Disables randomization of the virtual address space.   Turns  on
69              ADDR_NO_RANDOMIZE.
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71       -S, --whole-seconds
72              Obsolete bug emulation flag.  Turns on WHOLE_SECONDS.
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74       -T, --sticky-timeouts
75              This makes select(2), pselect(2), and ppoll(2) system calls pre‐
76              serve the timeout value instead of modifying it to  reflect  the
77              amount  of  time not slept when interrupted by a signal handler.
78              Use when program depends on this behavior.  For more details see
79              the  timeout  description  in  select(2)  manual page.  Turns on
80              STICKY_TIMEOUTS.
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82       -X, --read-implies-exec
83              If this  is  set  then  mmap(3)  PROT_READ  will  also  add  the
84              PROT_EXEC bit - as expected by legacy x86 binaries.  Notice that
85              the ELF loader will automatically set this bit when  it  encoun‐
86              ters a legacy binary.  Turns on READ_IMPLIES_EXEC.
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88       -Z, --mmap-page-zero
89              SVr4 bug emulation that will set mmap(3) page zero as read-only.
90              Use when program depends on this behavior, and the  source  code
91              is not available to be fixed.  Turns on MMAP_PAGE_ZERO.
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93       -V, --version
94              Display version information and exit.
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96       -h, --help
97              Display help text and exit.
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EXAMPLES

100       setarch --addr-no-randomize mytestprog
101       setarch ppc32 rpmbuild --target=ppc --rebuild foo.src.rpm
102       setarch ppc32 -v -vL3 rpmbuild --target=ppc --rebuild bar.src.rpm
103       setarch ppc32 --32bit rpmbuild --target=ppc --rebuild foo.src.rpm
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AUTHOR

106       Elliot Lee ⟨sopwith@redhat.com⟩
107       Jindrich Novy ⟨jnovy@redhat.com⟩
108       Karel Zak ⟨kzak@redhat.com⟩
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SEE ALSO

111       personality(2), select(2)
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AVAILABILITY

114       The  setarch command is part of the util-linux package and is available
115       from Linux Kernel Archive ⟨https://www.kernel.org/pub/linux/utils/util-
116       linux/⟩.
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120util-linux                       December 2017                      SETARCH(8)
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