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
  19 //applet:IF_SETARCH(APPLET(setarch, BB_DIR_BIN, BB_SUID_DROP))
  20 //applet:IF_SETARCH(APPLET_ODDNAME(linux32, setarch, BB_DIR_BIN, BB_SUID_DROP, linux32))
  21 //applet:IF_SETARCH(APPLET_ODDNAME(linux64, setarch, BB_DIR_BIN, BB_SUID_DROP, linux64))
  22
  23 //kbuild:lib-$(CONFIG_SETARCH) += setarch.o
  24
  25 //usage:#define setarch_trivial_usage
  26 //usage:       "PERSONALITY [-R] PROG ARGS"
  27 //usage:#define setarch_full_usage "\n\n"
  28 //usage:       "PERSONALITY may be:"
  29 //usage:   "\n""        linux32 Set 32bit uname emulation"
  30 //usage:   "\n""        linux64 Set 64bit uname emulation"
  31 //usage:   "\n"
  32 //usage:   "\n""        -R      Disable address space randomization"
  33 //usage:
  34 //usage:#define linux32_trivial_usage NOUSAGE_STR
  35 //usage:#define linux32_full_usage ""
  36 //usage:
  37 //usage:#define linux64_trivial_usage NOUSAGE_STR
  38 //usage:#define linux64_full_usage ""
  39
  40 #include "libbb.h"
  41 #include <sys/personality.h>
  42
  43 #ifndef ADDR_NO_RANDOMIZE
  44 # define ADDR_NO_RANDOMIZE       0x0040000
  45 #endif
  46
  47 int setarch_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  48 int setarch_main(int argc UNUSED_PARAM, char **argv)
  49 {
  50         unsigned opts;
  51         unsigned long pers;
  52
  53         /* Figure out what personality we are supposed to switch to ...
  54          * we can be invoked as either:
  55          * argv[0],argv[1] == "setarch","personality"
  56          * argv[0]         == "personality"
  57          */
  58         if (ENABLE_SETARCH && applet_name[0] == 's'
  59          && argv[1] && is_prefixed_with(argv[1], "linux")
  60         ) {
  61                 applet_name = argv[1];
  62                 argv++;
  63         }
  64         if (applet_name[5] == '6') /* linux64 */
  65                 pers = PER_LINUX;
  66         else if (applet_name[5] == '3') /* linux32 */
  67                 pers = PER_LINUX32;
  68         else
  69                 bb_show_usage();
  70
  71         opts = getopt32(argv, "+R"); /* '+': stop at first non-option */
  72         if (opts)
  73                 pers |= ADDR_NO_RANDOMIZE;
  74
  75         /* Try to set personality */
  76         if (personality(pers) < 0)
  77                 bb_perror_msg_and_die("personality(0x%lx)", pers);
  78
  79         argv += optind;
  80         if (!argv[0])
  81                 (--argv)[0] = (char*)"/bin/sh";
  82
  83         /* Try to execute the program */
  84         BB_EXECVP_or_die(argv);
  85 }