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:       select PLATFORM_LINUX
  13//config:       help
  14//config:       The linux32 utility is used to create a 32bit environment for the
  15//config:       specified program (usually a shell). It only makes sense to have
  16//config:       this util on a system that supports both 64bit and 32bit userland
  17//config:       (like amd64/x86, ppc64/ppc, sparc64/sparc, etc...).
  18//config:
  19//config:config LINUX32
  20//config:       bool "linux32 (3.3 kb)"
  21//config:       default y
  22//config:       select PLATFORM_LINUX
  23//config:       help
  24//config:       Alias to "setarch linux32".
  25//config:
  26//config:config LINUX64
  27//config:       bool "linux64 (3.3 kb)"
  28//config:       default y
  29//config:       select PLATFORM_LINUX
  30//config:       help
  31//config:       Alias to "setarch linux64".
  32
  33//applet:IF_SETARCH(APPLET_NOEXEC(setarch, setarch, BB_DIR_BIN, BB_SUID_DROP, setarch))
  34//                  APPLET_NOEXEC:name     main     location    suid_type     help
  35//applet:IF_LINUX32(APPLET_NOEXEC(linux32, setarch, BB_DIR_BIN, BB_SUID_DROP, linux32))
  36//applet:IF_LINUX64(APPLET_NOEXEC(linux64, setarch, BB_DIR_BIN, BB_SUID_DROP, linux64))
  37
  38//kbuild:lib-$(CONFIG_SETARCH) += setarch.o
  39//kbuild:lib-$(CONFIG_LINUX32) += setarch.o
  40//kbuild:lib-$(CONFIG_LINUX64) += setarch.o
  41
  42//usage:#define setarch_trivial_usage
  43//usage:       "PERSONALITY [-R] PROG ARGS"
  44//usage:#define setarch_full_usage "\n\n"
  45//usage:       "PERSONALITY may be:"
  46//usage:   "\n""        linux32 Set 32bit uname emulation"
  47//usage:   "\n""        linux64 Set 64bit uname emulation"
  48//usage:   "\n"
  49//usage:   "\n""        -R      Disable address space randomization"
  50//usage:
  51//usage:#define linux32_trivial_usage NOUSAGE_STR
  52//usage:#define linux32_full_usage ""
  53//usage:
  54//usage:#define linux64_trivial_usage NOUSAGE_STR
  55//usage:#define linux64_full_usage ""
  56
  57#include "libbb.h"
  58#include <sys/personality.h>
  59
  60#ifndef ADDR_NO_RANDOMIZE
  61# define ADDR_NO_RANDOMIZE       0x0040000
  62#endif
  63
  64int setarch_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  65int setarch_main(int argc UNUSED_PARAM, char **argv)
  66{
  67        unsigned opts;
  68        unsigned long pers;
  69
  70        /* Figure out what personality we are supposed to switch to ...
  71         * we can be invoked as either:
  72         * argv[0],argv[1] == "setarch","personality"
  73         * argv[0]         == "personality"
  74         */
  75        if (ENABLE_SETARCH && applet_name[0] == 's'
  76         && argv[1] && is_prefixed_with(argv[1], "linux")
  77        ) {
  78                argv++;
  79                applet_name = argv[0];
  80        }
  81        if ((!ENABLE_SETARCH && !ENABLE_LINUX32) || applet_name[5] == '6')
  82                /* linux64 */
  83                pers = PER_LINUX;
  84        else
  85        if ((!ENABLE_SETARCH && !ENABLE_LINUX64) || applet_name[5] == '3')
  86                /* linux32 */
  87                pers = PER_LINUX32;
  88        else
  89                bb_show_usage();
  90
  91        opts = getopt32(argv, "+R"); /* '+': stop at first non-option */
  92        if (opts)
  93                pers |= ADDR_NO_RANDOMIZE;
  94
  95        /* Try to set personality */
  96        if (personality(pers) < 0)
  97                bb_perror_msg_and_die("personality(0x%lx)", pers);
  98
  99        argv += optind;
 100        if (!argv[0])
 101                (--argv)[0] = (char*)"/bin/sh";
 102
 103        /* Try to execute the program */
 104        BB_EXECVP_or_die(argv);
 105}
 106