LXR busybox/util-linux/setarch.c

   1/* vi: set sw=4 ts=4: */
   2/*
   3 * linux32/linux64 allows for changing uname emulation.
   4 *
   5 * Copyright 2002 Andi Kleen, SuSE Labs.
   6 *
   7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   8 */
   9//config:config SETARCH
  10//config:       bool "setarch (3.6 kb)"
  11//config:       default y
  12//config:       help
  13//config:       The linux32 utility is used to create a 32bit environment for the
  14//config:       specified program (usually a shell). It only makes sense to have
  15//config:       this util on a system that supports both 64bit and 32bit userland
  16//config:       (like amd64/x86, ppc64/ppc, sparc64/sparc, etc...).
  17//config:
  18//config:config LINUX32
  19//config:       bool "linux32 (3.3 kb)"
  20//config:       default y
  21//config:       help
  22//config:       Alias to "setarch linux32".
  23//config:
  24//config:config LINUX64
  25//config:       bool "linux64 (3.3 kb)"
  26//config:       default y
  27//config:       help
  28//config:       Alias to "setarch linux64".
  29
  30//applet:IF_SETARCH(APPLET_NOEXEC(setarch, setarch, BB_DIR_BIN, BB_SUID_DROP, setarch))
  31//                  APPLET_NOEXEC:name     main     location    suid_type     help
  32//applet:IF_LINUX32(APPLET_NOEXEC(linux32, setarch, BB_DIR_BIN, BB_SUID_DROP, linux32))
  33//applet:IF_LINUX64(APPLET_NOEXEC(linux64, setarch, BB_DIR_BIN, BB_SUID_DROP, linux64))
  34
  35//kbuild:lib-$(CONFIG_SETARCH) += setarch.o
  36//kbuild:lib-$(CONFIG_LINUX32) += setarch.o
  37//kbuild:lib-$(CONFIG_LINUX64) += setarch.o
  38
  39//usage:#define setarch_trivial_usage
  40//usage:       "PERSONALITY [-R] PROG ARGS"
  41//usage:#define setarch_full_usage "\n\n"
  42//usage:       "PERSONALITY may be:"
  43//usage:   "\n""        linux32 Set 32bit uname emulation"
  44//usage:   "\n""        linux64 Set 64bit uname emulation"
  45//usage:   "\n"
  46//usage:   "\n""        -R      Disable address space randomization"
  47//usage:
  48//usage:#define linux32_trivial_usage NOUSAGE_STR
  49//usage:#define linux32_full_usage ""
  50//usage:
  51//usage:#define linux64_trivial_usage NOUSAGE_STR
  52//usage:#define linux64_full_usage ""
  53
  54#include "libbb.h"
  55#include <sys/personality.h>
  56
  57#ifndef ADDR_NO_RANDOMIZE
  58# define ADDR_NO_RANDOMIZE       0x0040000
  59#endif
  60
  61int setarch_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  62int setarch_main(int argc UNUSED_PARAM, char **argv)
  63{
  64        unsigned opts;
  65        unsigned long pers;
  66
  67        /* Figure out what personality we are supposed to switch to ...
  68         * we can be invoked as either:
  69         * argv[0],argv[1] == "setarch","personality"
  70         * argv[0]         == "personality"
  71         */
  72        if (ENABLE_SETARCH && applet_name[0] == 's'
  73         && argv[1] && is_prefixed_with(argv[1], "linux")
  74        ) {
  75                argv++;
  76                applet_name = argv[0];
  77        }
  78        if ((!ENABLE_SETARCH && !ENABLE_LINUX32) || applet_name[5] == '6')
  79                /* linux64 */
  80                pers = PER_LINUX;
  81        else
  82        if ((!ENABLE_SETARCH && !ENABLE_LINUX64) || applet_name[5] == '3')
  83                /* linux32 */
  84                pers = PER_LINUX32;
  85        else
  86                bb_show_usage();
  87
  88        opts = getopt32(argv, "+R"); /* '+': stop at first non-option */
  89        if (opts)
  90                pers |= ADDR_NO_RANDOMIZE;
  91
  92        /* Try to set personality */
  93        if (personality(pers) < 0)
  94                bb_perror_msg_and_die("personality(0x%lx)", pers);
  95
  96        argv += optind;
  97        if (!argv[0])
  98                (--argv)[0] = (char*)"/bin/sh";
  99
 100        /* Try to execute the program */
 101        BB_EXECVP_or_die(argv);
 102}
 103