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.
--show[=personality]
Show the currently active personality and flags. If the
personality argument is provided, it is shown instead of the current
one. personality is a hexadecimal number with values was described in
sys/personality.h.
--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(2) 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(2) 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>
