busybox/util-linux/setarch.c

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/* vi: set sw=4 ts=4: */
/*
* linux32/linux64 allows for changing uname emulation.
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*
* Copyright 2002 Andi Kleen, SuSE Labs.
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
//config:config SETARCH
//config: bool "setarch (3.6 kb)"
//config: default y
//config: help
//config: The linux32 utility is used to create a 32bit environment for the
//config: specified program (usually a shell). It only makes sense to have
//config: this util on a system that supports both 64bit and 32bit userland
//config: (like amd64/x86, ppc64/ppc, sparc64/sparc, etc...).
//config:
//config:config LINUX32
//config: bool "linux32 (3.3 kb)"
//config: default y
//config: help
//config: Alias to "setarch linux32".
//config:
//config:config LINUX64
//config: bool "linux64 (3.3 kb)"
//config: default y
//config: help
//config: Alias to "setarch linux64".
//applet:IF_SETARCH(APPLET_NOEXEC(setarch, setarch, BB_DIR_BIN, BB_SUID_DROP, setarch))
// APPLET_NOEXEC:name main location suid_type help
//applet:IF_LINUX32(APPLET_NOEXEC(linux32, setarch, BB_DIR_BIN, BB_SUID_DROP, linux32))
//applet:IF_LINUX64(APPLET_NOEXEC(linux64, setarch, BB_DIR_BIN, BB_SUID_DROP, linux64))
//kbuild:lib-$(CONFIG_SETARCH) += setarch.o
//kbuild:lib-$(CONFIG_LINUX32) += setarch.o
//kbuild:lib-$(CONFIG_LINUX64) += setarch.o
//usage:#define setarch_trivial_usage
//usage: "PERSONALITY [-R] PROG ARGS"
//usage:#define setarch_full_usage "\n\n"
//usage: "PERSONALITY may be:"
//usage: "\n"" linux32 Set 32bit uname emulation"
//usage: "\n"" linux64 Set 64bit uname emulation"
//usage: "\n"
//usage: "\n"" -R Disable address space randomization"
//usage:
//usage:#define linux32_trivial_usage NOUSAGE_STR
//usage:#define linux32_full_usage ""
//usage:
//usage:#define linux64_trivial_usage NOUSAGE_STR
//usage:#define linux64_full_usage ""
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#include "libbb.h"
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#include <sys/personality.h>
#ifndef ADDR_NO_RANDOMIZE
# define ADDR_NO_RANDOMIZE 0x0040000
#endif
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int setarch_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int setarch_main(int argc UNUSED_PARAM, char **argv)
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{
unsigned opts;
unsigned long pers;
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/* Figure out what personality we are supposed to switch to ...
* we can be invoked as either:
* argv[0],argv[1] == "setarch","personality"
* argv[0] == "personality"
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*/
if (ENABLE_SETARCH && applet_name[0] == 's'
&& argv[1] && is_prefixed_with(argv[1], "linux")
) {
argv++;
applet_name = argv[0];
}
if ((!ENABLE_SETARCH && !ENABLE_LINUX32) || applet_name[5] == '6')
/* linux64 */
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pers = PER_LINUX;
else
if ((!ENABLE_SETARCH && !ENABLE_LINUX64) || applet_name[5] == '3')
/* linux32 */
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pers = PER_LINUX32;
else
bb_show_usage();
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opts = getopt32(argv, "+R"); /* '+': stop at first non-option */
if (opts)
pers |= ADDR_NO_RANDOMIZE;
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/* Try to set personality */
if (personality(pers) < 0)
bb_perror_msg_and_die("personality(0x%lx)", pers);
argv += optind;
if (!argv[0])
(--argv)[0] = (char*)"/bin/sh";
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/* Try to execute the program */
BB_EXECVP_or_die(argv);
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}