sys-utils/setarch.c

   1 /*
   2  * Copyright (C) 2003-2007 Red Hat, Inc.
   3  *
   4  * This file is part of util-linux.
   5  *
   6  * This file is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This file is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  *
  17  * Written by Elliot Lee <sopwith@redhat.com>
  18  * New personality options & code added by Jindrich Novy <jnovy@redhat.com>
  19  * ADD_NO_RANDOMIZE flag added by Arjan van de Ven <arjanv@redhat.com>
  20  * Help and MIPS support from Mike Frysinger (vapier@gentoo.org)
  21  * Better error handling from Dmitry V. Levin (ldv@altlinux.org)
  22  *
  23  * based on ideas from the ppc32 util by Guy Streeter (2002-01), based on the
  24  * sparc32 util by Jakub Jelinek (1998, 1999)
  25  */
  26
  27 #include <sys/personality.h>
  28 #include <unistd.h>
  29 #include <stdio.h>
  30 #include <string.h>
  31 #include <stdlib.h>
  32 #include <getopt.h>
  33 #include <limits.h>
  34 #include <sys/utsname.h>
  35 #include "nls.h"
  36 #include "c.h"
  37 #include "closestream.h"
  38
  39 #ifndef HAVE_PERSONALITY
  40 # include <syscall.h>
  41 # define personality(pers) ((long)syscall(SYS_personality, pers))
  42 #endif
  43
  44 #define turn_on(_flag, _opts) \
  45         do { \
  46                 (_opts) |= _flag; \
  47                 if (verbose) \
  48                         printf(_("Switching on %s.\n"), #_flag); \
  49         } while(0)
  50
  51 #ifndef UNAME26
  52 # define UNAME26                 0x0020000
  53 #endif
  54 #ifndef ADDR_NO_RANDOMIZE
  55 # define ADDR_NO_RANDOMIZE       0x0040000
  56 #endif
  57 #ifndef FDPIC_FUNCPTRS
  58 # define FDPIC_FUNCPTRS          0x0080000
  59 #endif
  60 #ifndef MMAP_PAGE_ZERO
  61 # define MMAP_PAGE_ZERO          0x0100000
  62 #endif
  63 #ifndef ADDR_COMPAT_LAYOUT
  64 # define ADDR_COMPAT_LAYOUT      0x0200000
  65 #endif
  66 #ifndef READ_IMPLIES_EXEC
  67 # define READ_IMPLIES_EXEC       0x0400000
  68 #endif
  69 #ifndef ADDR_LIMIT_32BIT
  70 # define ADDR_LIMIT_32BIT        0x0800000
  71 #endif
  72 #ifndef SHORT_INODE
  73 # define SHORT_INODE             0x1000000
  74 #endif
  75 #ifndef WHOLE_SECONDS
  76 # define WHOLE_SECONDS           0x2000000
  77 #endif
  78 #ifndef STICKY_TIMEOUTS
  79 # define STICKY_TIMEOUTS         0x4000000
  80 #endif
  81 #ifndef ADDR_LIMIT_3GB
  82 # define ADDR_LIMIT_3GB          0x8000000
  83 #endif
  84
  85 static int archwrapper;
  86
  87 static void __attribute__((__noreturn__)) show_help(void)
  88 {
  89         fputs(USAGE_HEADER, stdout);
  90         if (!archwrapper)
  91                 printf(_(" %s <arch> [options] [<program> [<argument>...]]\n"), program_invocation_short_name);
  92         else
  93                 printf(_(" %s [options] [<program> [<argument>...]]\n"), program_invocation_short_name);
  94
  95         fputs(USAGE_SEPARATOR, stdout);
  96         fputs(_("Change the reported architecture and set personality flags.\n"), stdout);
  97
  98         fputs(USAGE_OPTIONS, stdout);
  99         fputs(_(" -B, --32bit              turns on ADDR_LIMIT_32BIT\n"), stdout);
 100         fputs(_(" -F, --fdpic-funcptrs     makes function pointers point to descriptors\n"), stdout);
 101         fputs(_(" -I, --short-inode        turns on SHORT_INODE\n"), stdout);
 102         fputs(_(" -L, --addr-compat-layout changes the way virtual memory is allocated\n"), stdout);
 103         fputs(_(" -R, --addr-no-randomize  disables randomization of the virtual address space\n"), stdout);
 104         fputs(_(" -S, --whole-seconds      turns on WHOLE_SECONDS\n"), stdout);
 105         fputs(_(" -T, --sticky-timeouts    turns on STICKY_TIMEOUTS\n"), stdout);
 106         fputs(_(" -X, --read-implies-exec  turns on READ_IMPLIES_EXEC\n"), stdout);
 107         fputs(_(" -Z, --mmap-page-zero     turns on MMAP_PAGE_ZERO\n"), stdout);
 108         fputs(_(" -3, --3gb                limits the used address space to a maximum of 3 GB\n"), stdout);
 109         fputs(_("     --4gb                ignored (for backward compatibility only)\n"), stdout);
 110         fputs(_("     --uname-2.6          turns on UNAME26\n"), stdout);
 111         fputs(_(" -v, --verbose            say what options are being switched on\n"), stdout);
 112
 113         if (!archwrapper)
 114                 fputs(_("     --list               list settable architectures, and exit\n"), stdout);
 115
 116         fputs(USAGE_SEPARATOR, stdout);
 117         fputs(USAGE_HELP, stdout);
 118         fputs(USAGE_VERSION, stdout);
 119         printf(USAGE_MAN_TAIL("setarch(8)"));
 120
 121         exit(EXIT_SUCCESS);
 122 }
 123
 124 static void __attribute__((__noreturn__)) show_usage(const char *s)
 125 {
 126         if (s)
 127                 errx(EXIT_FAILURE,
 128                      _("%s\nTry `%s --help' for more information."), s,
 129                      program_invocation_short_name);
 130         else
 131                 errx(EXIT_FAILURE, _("Try `%s --help' for more information."),
 132                      program_invocation_short_name);
 133 }
 134
 135 static void __attribute__((__noreturn__))
 136     show_version(void)
 137 {
 138         printf(UTIL_LINUX_VERSION);
 139         exit(EXIT_SUCCESS);
 140 }
 141
 142 static int set_arch(const char *pers, unsigned long options, int list)
 143 {
 144         struct utsname un;
 145         int i;
 146         unsigned long pers_value;
 147
 148         struct {
 149                 int perval;
 150                 const char *target_arch, *result_arch;
 151         } transitions[] = {
 152                 {UNAME26,       "uname26",      NULL},
 153                 {PER_LINUX32,   "linux32",      NULL},
 154                 {PER_LINUX,     "linux64",      NULL},
 155 #if defined(__powerpc__) || defined(__powerpc64__)
 156 # ifdef __BIG_ENDIAN__
 157                 {PER_LINUX32,   "ppc32",        "ppc"},
 158                 {PER_LINUX32,   "ppc",          "ppc"},
 159                 {PER_LINUX,     "ppc64",        "ppc64"},
 160                 {PER_LINUX,     "ppc64pseries", "ppc64"},
 161                 {PER_LINUX,     "ppc64iseries", "ppc64"},
 162 # else
 163                 {PER_LINUX32,   "ppc32le",      "ppcle"},
 164                 {PER_LINUX32,   "ppcle",        "ppcle"},
 165                 {PER_LINUX,     "ppc64le",      "ppc64le"},
 166 # endif
 167 #endif
 168 #if defined(__x86_64__) || defined(__i386__) || defined(__ia64__)
 169                 {PER_LINUX32,   "i386",         "i386"},
 170                 {PER_LINUX32,   "i486",         "i386"},
 171                 {PER_LINUX32,   "i586",         "i386"},
 172                 {PER_LINUX32,   "i686",         "i386"},
 173                 {PER_LINUX32,   "athlon",       "i386"},
 174 #endif
 175 #if defined(__x86_64__) || defined(__i386__)
 176                 {PER_LINUX,     "x86_64",       "x86_64"},
 177 #endif
 178 #if defined(__ia64__) || defined(__i386__)
 179                 {PER_LINUX,     "ia64",         "ia64"},
 180 #endif
 181 #if defined(__hppa__)
 182                 {PER_LINUX32,   "parisc32",     "parisc"},
 183                 {PER_LINUX32,   "parisc",       "parisc"},
 184                 {PER_LINUX,     "parisc64",     "parisc64"},
 185 #endif
 186 #if defined(__s390x__) || defined(__s390__)
 187                 {PER_LINUX32,   "s390",         "s390"},
 188                 {PER_LINUX,     "s390x",        "s390x"},
 189 #endif
 190 #if defined(__sparc64__) || defined(__sparc__)
 191                 {PER_LINUX32,   "sparc",        "sparc"},
 192                 {PER_LINUX32,   "sparc32bash",  "sparc"},
 193                 {PER_LINUX32,   "sparc32",      "sparc"},
 194                 {PER_LINUX,     "sparc64",      "sparc64"},
 195 #endif
 196 #if defined(__mips64__) || defined(__mips__)
 197                 {PER_LINUX32,   "mips32",       "mips"},
 198                 {PER_LINUX32,   "mips",         "mips"},
 199                 {PER_LINUX,     "mips64",       "mips64"},
 200 #endif
 201 #if defined(__alpha__)
 202                 {PER_LINUX,     "alpha",        "alpha"},
 203                 {PER_LINUX,     "alphaev5",     "alpha"},
 204                 {PER_LINUX,     "alphaev56",    "alpha"},
 205                 {PER_LINUX,     "alphaev6",     "alpha"},
 206                 {PER_LINUX,     "alphaev67",    "alpha"},
 207 #endif
 208                 /* place holder, will be filled up at runtime */
 209                 {-1,            NULL,           NULL},
 210                 {-1,            NULL,           NULL}
 211         };
 212
 213         /* Add the trivial transition {PER_LINUX, machine, machine} if no
 214          * such target_arch is hardcoded yet.  */
 215         uname(&un);
 216         for (i = 0; transitions[i].perval >= 0; i++)
 217                 if (!strcmp(un.machine, transitions[i].target_arch))
 218                         break;
 219         if (transitions[i].perval < 0) {
 220                 unsigned long wrdsz = CHAR_BIT * sizeof(void *);
 221                 if (wrdsz == 32 || wrdsz == 64) {
 222                         /* fill up the place holder */
 223                         transitions[i].perval = wrdsz == 32 ? PER_LINUX32 : PER_LINUX;
 224                         transitions[i].target_arch = un.machine;
 225                         transitions[i].result_arch = un.machine;
 226                 }
 227         }
 228         if (list) {
 229                 for (i = 0; transitions[i].target_arch != NULL; i++)
 230                         printf("%s\n", transitions[i].target_arch);
 231                 return 0;
 232         }
 233         for (i = 0; transitions[i].perval >= 0; i++)
 234                 if (!strcmp(pers, transitions[i].target_arch))
 235                         break;
 236         if (transitions[i].perval < 0)
 237                 errx(EXIT_FAILURE, _("%s: Unrecognized architecture"), pers);
 238         pers_value = transitions[i].perval | options;
 239         if (personality(pers_value) < 0) {
 240                 /*
 241                  * Depending on architecture and kernel version, personality
 242                  * syscall is either capable or incapable of returning an error.
 243                  * If the return value is not an error, then it's the previous
 244                  * personality value, which can be an arbitrary value
 245                  * undistinguishable from an error value.
 246                  * To make things clear, a second call is needed.
 247                  */
 248                 if (personality(pers_value) < 0)
 249                         return 1;
 250         }
 251         uname(&un);
 252         if (transitions[i].result_arch && strcmp(un.machine, transitions[i].result_arch)) {
 253                 if (strcmp(transitions[i].result_arch, "i386")
 254                     || (strcmp(un.machine, "i486")
 255                         && strcmp(un.machine, "i586")
 256                         && strcmp(un.machine, "i686")
 257                         && strcmp(un.machine, "athlon")))
 258                         errx(EXIT_FAILURE, _("Kernel cannot set architecture to %s"), pers);
 259         }
 260         return 0;
 261 }
 262
 263 int main(int argc, char *argv[])
 264 {
 265         const char *arch = NULL;
 266         unsigned long options = 0;
 267         int verbose = 0;
 268         int c;
 269
 270         /* Options without equivalent short options */
 271         enum {
 272                 OPT_4GB = CHAR_MAX + 1,
 273                 OPT_UNAME26,
 274                 OPT_LIST
 275         };
 276
 277         /* Options --3gb and --4gb are for compatibitity with an old
 278          * Debian setarch implementation.  */
 279         static const struct option longopts[] = {
 280                 {"help",                no_argument,    NULL,   'h'},
 281                 {"version",             no_argument,    NULL,   'V'},
 282                 {"verbose",             no_argument,    NULL,   'v'},
 283                 {"addr-no-randomize",   no_argument,    NULL,   'R'},
 284                 {"fdpic-funcptrs",      no_argument,    NULL,   'F'},
 285                 {"mmap-page-zero",      no_argument,    NULL,   'Z'},
 286                 {"addr-compat-layout",  no_argument,    NULL,   'L'},
 287                 {"read-implies-exec",   no_argument,    NULL,   'X'},
 288                 {"32bit",               no_argument,    NULL,   'B'},
 289                 {"short-inode",         no_argument,    NULL,   'I'},
 290                 {"whole-seconds",       no_argument,    NULL,   'S'},
 291                 {"sticky-timeouts",     no_argument,    NULL,   'T'},
 292                 {"3gb",                 no_argument,    NULL,   '3'},
 293                 {"4gb",                 no_argument,    NULL,   OPT_4GB},
 294                 {"uname-2.6",           no_argument,    NULL,   OPT_UNAME26},
 295                 {"list",                no_argument,    NULL,   OPT_LIST},
 296                 {NULL,                  0,              NULL,   0}
 297         };
 298
 299         setlocale(LC_ALL, "");
 300         bindtextdomain(PACKAGE, LOCALEDIR);
 301         textdomain(PACKAGE);
 302         atexit(close_stdout);
 303
 304         if (argc < 1)
 305                 show_usage(_("Not enough arguments"));
 306
 307         archwrapper = strcmp(program_invocation_short_name, "setarch") != 0;
 308         if (archwrapper)
 309                 arch = program_invocation_short_name;   /* symlinks to setarch */
 310         else {
 311                 if (1 < argc && *argv[1] != '-') {
 312                         arch = argv[1];
 313                         argv[1] = argv[0];      /* for getopt_long() to get the program name */
 314                         argv++;
 315                         argc--;
 316                 }
 317         }
 318
 319 #if defined(__sparc64__) || defined(__sparc__)
 320         if (archwrapper && strcmp(arch, "sparc32bash") == 0) {
 321                 if (set_arch(arch, 0L, 0))
 322                         err(EXIT_FAILURE, _("Failed to set personality to %s"), arch);
 323                 execl("/bin/bash", NULL);
 324                 err(EXIT_FAILURE, _("failed to execute %s"), "/bin/bash");
 325         }
 326 #endif
 327
 328         while ((c = getopt_long(argc, argv, "+hVv3BFILRSTXZ", longopts, NULL)) != -1) {
 329                 switch (c) {
 330                 case 'h':
 331                         show_help();
 332                         break;
 333                 case 'V':
 334                         show_version();
 335                         break;
 336                 case 'v':
 337                         verbose = 1;
 338                         break;
 339                 case 'R':
 340                         turn_on(ADDR_NO_RANDOMIZE, options);
 341                         break;
 342                 case 'F':
 343                         turn_on(FDPIC_FUNCPTRS, options);
 344                         break;
 345                 case 'Z':
 346                         turn_on(MMAP_PAGE_ZERO, options);
 347                         break;
 348                 case 'L':
 349                         turn_on(ADDR_COMPAT_LAYOUT, options);
 350                         break;
 351                 case 'X':
 352                         turn_on(READ_IMPLIES_EXEC, options);
 353                         break;
 354                 case 'B':
 355                         turn_on(ADDR_LIMIT_32BIT, options);
 356                         break;
 357                 case 'I':
 358                         turn_on(SHORT_INODE, options);
 359                         break;
 360                 case 'S':
 361                         turn_on(WHOLE_SECONDS, options);
 362                         break;
 363                 case 'T':
 364                         turn_on(STICKY_TIMEOUTS, options);
 365                         break;
 366                 case '3':
 367                         turn_on(ADDR_LIMIT_3GB, options);
 368                         break;
 369                 case OPT_4GB:   /* just ignore this one */
 370                         break;
 371                 case OPT_UNAME26:
 372                         turn_on(UNAME26, options);
 373                         break;
 374                 case OPT_LIST:
 375                         if (!archwrapper) {
 376                                 set_arch(NULL, 0, 1);
 377                                 return EXIT_SUCCESS;
 378                         } else
 379                                 warnx(_("unrecognized option '--list'"));
 380                 default:
 381                         show_usage(NULL);
 382                 }
 383         }
 384
 385         if (!arch)
 386                 errx(EXIT_FAILURE, _("no architecture argument specified"));
 387
 388         argc -= optind;
 389         argv += optind;
 390
 391         if (set_arch(arch, options, 0))
 392                 err(EXIT_FAILURE, _("failed to set personality to %s"), arch);
 393
 394         /* flush all output streams before exec */
 395         fflush(NULL);
 396
 397         if (!argc) {
 398                 execl("/bin/sh", "-sh", NULL);
 399                 err(EXIT_FAILURE, _("failed to execute %s"), "/bin/sh");
 400         }
 401
 402         execvp(argv[0], argv);
 403         err(EXIT_FAILURE, "%s", argv[0]);
 404         return EXIT_FAILURE;
 405 }