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 can
22       also be used 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
31           List the architectures that setarch knows about. Whether setarch
32           can actually set each of these architectures depends on the running
33           kernel.
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35       --show[=personality]
36           Show the currently active personality and flags. If the personality
37           argument is provided, it is shown instead of the current one.
38           personality is a hexadecimal number with values was described in
39           sys/personality.h.
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41       --uname-2.6
42           Causes the program to see a kernel version number beginning with
43           2.6. Turns on UNAME26.
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45       -v, --verbose
46           Be verbose.
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48       -3, --3gb
49           Specifies program should use a maximum of 3GB of address space.
50           Supported on x86. Turns on ADDR_LIMIT_3GB.
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52       --4gb
53           This option has no effect. It is retained for backward
54           compatibility only, and may be removed in future releases.
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56       -B, --32bit
57           Limit the address space to 32 bits to emulate hardware. Supported
58           on ARM and Alpha. Turns on ADDR_LIMIT_32BIT.
59
60       -F, --fdpic-funcptrs
61           Treat user-space function pointers to signal handlers as pointers
62           to address descriptors. This option has no effect on architectures
63           that do not support FDPIC ELF binaries. In kernel v4.14 support is
64           limited to ARM, Blackfin, Fujitsu FR-V, and SuperH CPU
65           architectures.
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67       -I, --short-inode
68           Obsolete bug emulation flag. Turns on SHORT_INODE.
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70       -L, --addr-compat-layout
71           Provide legacy virtual address space layout. Use when the program
72           binary does not have PT_GNU_STACK ELF header. Turns on
73           ADDR_COMPAT_LAYOUT.
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75       -R, --addr-no-randomize
76           Disables randomization of the virtual address space. Turns on
77           ADDR_NO_RANDOMIZE.
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79       -S, --whole-seconds
80           Obsolete bug emulation flag. Turns on WHOLE_SECONDS.
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82       -T, --sticky-timeouts
83           This makes select(2), pselect(2), and ppoll(2) system calls
84           preserve the timeout value instead of modifying it to reflect the
85           amount of time not slept when interrupted by a signal handler. Use
86           when program depends on this behavior. For more details see the
87           timeout description in select(2) manual page. Turns on
88           STICKY_TIMEOUTS.
89
90       -X, --read-implies-exec
91           If this is set then mmap(2) PROT_READ will also add the PROT_EXEC
92           bit - as expected by legacy x86 binaries. Notice that the ELF
93           loader will automatically set this bit when it encounters a legacy
94           binary. Turns on READ_IMPLIES_EXEC.
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96       -Z, --mmap-page-zero
97           SVr4 bug emulation that will set mmap(2) page zero as read-only.
98           Use when program depends on this behavior, and the source code is
99           not available to be fixed. Turns on MMAP_PAGE_ZERO.
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101       -h, --help
102           Display help text and exit.
103
104       -V, --version
105           Print version and exit.
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EXAMPLE

108           setarch --addr-no-randomize mytestprog
109           setarch ppc32 rpmbuild --target=ppc --rebuild foo.src.rpm
110           setarch ppc32 -v -vL3 rpmbuild --target=ppc --rebuild bar.src.rpm
111           setarch ppc32 --32bit rpmbuild --target=ppc --rebuild foo.src.rpm
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AUTHORS

114       Elliot Lee <sopwith@redhat.com>, Jindrich Novy <jnovy@redhat.com>,
115       Karel Zak <kzak@redhat.com>
116

SEE ALSO

118       personality(2), select(2)
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REPORTING BUGS

121       For bug reports, use the issue tracker at
122       https://github.com/util-linux/util-linux/issues.
123

AVAILABILITY

125       The setarch command is part of the util-linux package which can be
126       downloaded from Linux Kernel Archive
127       <https://www.kernel.org/pub/linux/utils/util-linux/>.
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131util-linux 2.39.2                 2023-06-14                        SETARCH(8)
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