setarch - change reported architecture in new program environment
and/or set personality flags
setarch [arch] [options] [program
[argument...]]
setarch --list|-h|-V
arch [options] [program [argument...]]
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.
- --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.
- -V, --version
- Display version information and exit.
- -h, --help
- Display help text and exit.
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