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"
  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"
  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"
  28 //config:       default y
  29 //config:       select PLATFORM_LINUX
  30 //config:       help
  31 //config:         Alias to "setarch linux64".
  32
  33 //applet:IF_SETARCH(APPLET(setarch, BB_DIR_BIN, BB_SUID_DROP))
  34 //applet:IF_LINUX32(APPLET_ODDNAME(linux32, setarch, BB_DIR_BIN, BB_SUID_DROP, linux32))
  35 //applet:IF_LINUX64(APPLET_ODDNAME(linux64, setarch, BB_DIR_BIN, BB_SUID_DROP, linux64))
  36
  37 //kbuild:lib-$(CONFIG_SETARCH) += setarch.o
  38 //kbuild:lib-$(CONFIG_LINUX32) += setarch.o
  39 //kbuild:lib-$(CONFIG_LINUX64) += setarch.o
  40
  41 //usage:#define setarch_trivial_usage
  42 //usage:       "PERSONALITY [-R] PROG ARGS"
  43 //usage:#define setarch_full_usage "\n\n"
  44 //usage:       "PERSONALITY may be:"
  45 //usage:   "\n""        linux32 Set 32bit uname emulation"
  46 //usage:   "\n""        linux64 Set 64bit uname emulation"
  47 //usage:   "\n"
  48 //usage:   "\n""        -R      Disable address space randomization"
  49 //usage:
  50 //usage:#define linux32_trivial_usage NOUSAGE_STR
  51 //usage:#define linux32_full_usage ""
  52 //usage:
  53 //usage:#define linux64_trivial_usage NOUSAGE_STR
  54 //usage:#define linux64_full_usage ""
  55
  56 #include "libbb.h"
  57 #include <sys/personality.h>
  58
  59 #ifndef ADDR_NO_RANDOMIZE
  60 # define ADDR_NO_RANDOMIZE       0x0040000
  61 #endif
  62
  63 int setarch_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  64 int setarch_main(int argc UNUSED_PARAM, char **argv)
  65 {
  66         unsigned opts;
  67         unsigned long pers;
  68
  69         /* Figure out what personality we are supposed to switch to ...
  70          * we can be invoked as either:
  71          * argv[0],argv[1] == "setarch","personality"
  72          * argv[0]         == "personality"
  73          */
  74         if (ENABLE_SETARCH && applet_name[0] == 's'
  75          && argv[1] && is_prefixed_with(argv[1], "linux")
  76         ) {
  77                 argv++;
  78                 applet_name = argv[0];
  79         }
  80         if ((!ENABLE_SETARCH && !ENABLE_LINUX32) || applet_name[5] == '6')
  81                 /* linux64 */
  82                 pers = PER_LINUX;
  83         else
  84         if ((!ENABLE_SETARCH && !ENABLE_LINUX64) || applet_name[5] == '3')
  85                 /* linux32 */
  86                 pers = PER_LINUX32;
  87         else
  88                 bb_show_usage();
  89
  90         opts = getopt32(argv, "+R"); /* '+': stop at first non-option */
  91         if (opts)
  92                 pers |= ADDR_NO_RANDOMIZE;
  93
  94         /* Try to set personality */
  95         if (personality(pers) < 0)
  96                 bb_perror_msg_and_die("personality(0x%lx)", pers);
  97
  98         argv += optind;
  99         if (!argv[0])
 100                 (--argv)[0] = (char*)"/bin/sh";
 101
 102         /* Try to execute the program */
 103         BB_EXECVP_or_die(argv);
 104 }