SETARCH(8) System Administration SETARCH(8)
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/>.
util-linux 2.38.1 2022-05-11 SETARCH(8)
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