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
  86 struct arch_domain {
  87         int             perval;         /* PER_* */
  88         const char      *target_arch;
  89         const char      *result_arch;
  90 };
  91
  92
  93 static void __attribute__((__noreturn__)) usage(int archwrapper)
  94 {
  95         fputs(USAGE_HEADER, stdout);
  96         if (!archwrapper)
  97                 printf(_(" %s [<arch>] [options] [<program> [<argument>...]]\n"), program_invocation_short_name);
  98         else
  99                 printf(_(" %s [options] [<program> [<argument>...]]\n"), program_invocation_short_name);
 100
 101         fputs(USAGE_SEPARATOR, stdout);
 102         fputs(_("Change the reported architecture and set personality flags.\n"), stdout);
 103
 104         fputs(USAGE_OPTIONS, stdout);
 105         fputs(_(" -B, --32bit              turns on ADDR_LIMIT_32BIT\n"), stdout);
 106         fputs(_(" -F, --fdpic-funcptrs     makes function pointers point to descriptors\n"), stdout);
 107         fputs(_(" -I, --short-inode        turns on SHORT_INODE\n"), stdout);
 108         fputs(_(" -L, --addr-compat-layout changes the way virtual memory is allocated\n"), stdout);
 109         fputs(_(" -R, --addr-no-randomize  disables randomization of the virtual address space\n"), stdout);
 110         fputs(_(" -S, --whole-seconds      turns on WHOLE_SECONDS\n"), stdout);
 111         fputs(_(" -T, --sticky-timeouts    turns on STICKY_TIMEOUTS\n"), stdout);
 112         fputs(_(" -X, --read-implies-exec  turns on READ_IMPLIES_EXEC\n"), stdout);
 113         fputs(_(" -Z, --mmap-page-zero     turns on MMAP_PAGE_ZERO\n"), stdout);
 114         fputs(_(" -3, --3gb                limits the used address space to a maximum of 3 GB\n"), stdout);
 115         fputs(_("     --4gb                ignored (for backward compatibility only)\n"), stdout);
 116         fputs(_("     --uname-2.6          turns on UNAME26\n"), stdout);
 117         fputs(_(" -v, --verbose            say what options are being switched on\n"), stdout);
 118
 119         if (!archwrapper)
 120                 fputs(_("     --list               list settable architectures, and exit\n"), stdout);
 121
 122         fputs(USAGE_SEPARATOR, stdout);
 123         printf(USAGE_HELP_OPTIONS(26));
 124         printf(USAGE_MAN_TAIL("setarch(8)"));
 125
 126         exit(EXIT_SUCCESS);
 127 }
 128
 129 /*
 130  * Returns inilialized list of all available execution domains.
 131  */
 132 static struct arch_domain *init_arch_domains(void)
 133 {
 134         static struct utsname un;
 135         size_t i;
 136
 137         static struct arch_domain transitions[] =
 138         {
 139                 {UNAME26,       "uname26",      NULL},
 140                 {PER_LINUX32,   "linux32",      NULL},
 141                 {PER_LINUX,     "linux64",      NULL},
 142 #if defined(__powerpc__) || defined(__powerpc64__)
 143 # ifdef __BIG_ENDIAN__
 144                 {PER_LINUX32,   "ppc32",        "ppc"},
 145                 {PER_LINUX32,   "ppc",          "ppc"},
 146                 {PER_LINUX,     "ppc64",        "ppc64"},
 147                 {PER_LINUX,     "ppc64pseries", "ppc64"},
 148                 {PER_LINUX,     "ppc64iseries", "ppc64"},
 149 # else
 150                 {PER_LINUX32,   "ppc32",        "ppcle"},
 151                 {PER_LINUX32,   "ppc",          "ppcle"},
 152                 {PER_LINUX32,   "ppc32le",      "ppcle"},
 153                 {PER_LINUX32,   "ppcle",        "ppcle"},
 154                 {PER_LINUX,     "ppc64le",      "ppc64le"},
 155 # endif
 156 #endif
 157 #if defined(__x86_64__) || defined(__i386__) || defined(__ia64__)
 158                 {PER_LINUX32,   "i386",         "i386"},
 159                 {PER_LINUX32,   "i486",         "i386"},
 160                 {PER_LINUX32,   "i586",         "i386"},
 161                 {PER_LINUX32,   "i686",         "i386"},
 162                 {PER_LINUX32,   "athlon",       "i386"},
 163 #endif
 164 #if defined(__x86_64__) || defined(__i386__)
 165                 {PER_LINUX,     "x86_64",       "x86_64"},
 166 #endif
 167 #if defined(__ia64__) || defined(__i386__)
 168                 {PER_LINUX,     "ia64",         "ia64"},
 169 #endif
 170 #if defined(__hppa__)
 171                 {PER_LINUX32,   "parisc32",     "parisc"},
 172                 {PER_LINUX32,   "parisc",       "parisc"},
 173                 {PER_LINUX,     "parisc64",     "parisc64"},
 174 #endif
 175 #if defined(__s390x__) || defined(__s390__)
 176                 {PER_LINUX32,   "s390",         "s390"},
 177                 {PER_LINUX,     "s390x",        "s390x"},
 178 #endif
 179 #if defined(__sparc64__) || defined(__sparc__)
 180                 {PER_LINUX32,   "sparc",        "sparc"},
 181                 {PER_LINUX32,   "sparc32bash",  "sparc"},
 182                 {PER_LINUX32,   "sparc32",      "sparc"},
 183                 {PER_LINUX,     "sparc64",      "sparc64"},
 184 #endif
 185 #if defined(__mips64__) || defined(__mips__)
 186                 {PER_LINUX32,   "mips32",       "mips"},
 187                 {PER_LINUX32,   "mips",         "mips"},
 188                 {PER_LINUX,     "mips64",       "mips64"},
 189 #endif
 190 #if defined(__alpha__)
 191                 {PER_LINUX,     "alpha",        "alpha"},
 192                 {PER_LINUX,     "alphaev5",     "alpha"},
 193                 {PER_LINUX,     "alphaev56",    "alpha"},
 194                 {PER_LINUX,     "alphaev6",     "alpha"},
 195                 {PER_LINUX,     "alphaev67",    "alpha"},
 196 #endif
 197                 /* place holder, will be filled up at runtime */
 198                 {-1,            NULL,           NULL},
 199                 {-1,            NULL,           NULL}
 200         };
 201
 202         /* Add the trivial transition {PER_LINUX, machine, machine} if no
 203          * such target_arch is hardcoded yet.  */
 204         uname(&un);
 205         for (i = 0; transitions[i].perval >= 0; i++)
 206                 if (!strcmp(un.machine, transitions[i].target_arch))
 207                         break;
 208         if (transitions[i].perval < 0) {
 209                 unsigned long wrdsz = CHAR_BIT * sizeof(void *);
 210                 if (wrdsz == 32 || wrdsz == 64) {
 211                         /* fill up the place holder */
 212                         transitions[i].perval = wrdsz == 32 ? PER_LINUX32 : PER_LINUX;
 213                         transitions[i].target_arch = un.machine;
 214                         transitions[i].result_arch = un.machine;
 215                 }
 216         }
 217
 218         return transitions;
 219 }
 220
 221 /*
 222  * List all execution domains from transitions
 223  */
 224 static void list_arch_domains(struct arch_domain *doms)
 225 {
 226         struct arch_domain *d;
 227
 228         for (d = doms; d->target_arch != NULL; d++)
 229                 printf("%s\n", d->target_arch);
 230 }
 231
 232 static struct arch_domain *get_arch_domain(struct arch_domain *doms, const char *pers)
 233 {
 234         struct arch_domain *d;
 235
 236         for (d = doms; d->perval >= 0; d++) {
 237                 if (!strcmp(pers, d->target_arch))
 238                         break;
 239         }
 240
 241         return !d || d->perval < 0 ? NULL : d;
 242 }
 243
 244 static void verify_arch_domain(struct arch_domain *dom, const char *wanted)
 245 {
 246         struct utsname un;
 247
 248         if (!dom || !dom->result_arch)
 249                 return;
 250
 251         uname(&un);
 252         if (strcmp(un.machine, dom->result_arch)) {
 253                 if (strcmp(dom->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"), wanted);
 259         }
 260 }
 261
 262 int main(int argc, char *argv[])
 263 {
 264         const char *arch = NULL;
 265         unsigned long options = 0;
 266         int verbose = 0;
 267         int archwrapper;
 268         int c;
 269         struct arch_domain *doms, *target;
 270         unsigned long pers_value = 0;
 271         char *shell = NULL, *shell_arg = NULL;
 272
 273         /* Options without equivalent short options */
 274         enum {
 275                 OPT_4GB = CHAR_MAX + 1,
 276                 OPT_UNAME26,
 277                 OPT_LIST
 278         };
 279
 280         /* Options --3gb and --4gb are for compatibility with an old
 281          * Debian setarch implementation.  */
 282         static const struct option longopts[] = {
 283                 {"help",                no_argument,    NULL,   'h'},
 284                 {"version",             no_argument,    NULL,   'V'},
 285                 {"verbose",             no_argument,    NULL,   'v'},
 286                 {"addr-no-randomize",   no_argument,    NULL,   'R'},
 287                 {"fdpic-funcptrs",      no_argument,    NULL,   'F'},
 288                 {"mmap-page-zero",      no_argument,    NULL,   'Z'},
 289                 {"addr-compat-layout",  no_argument,    NULL,   'L'},
 290                 {"read-implies-exec",   no_argument,    NULL,   'X'},
 291                 {"32bit",               no_argument,    NULL,   'B'},
 292                 {"short-inode",         no_argument,    NULL,   'I'},
 293                 {"whole-seconds",       no_argument,    NULL,   'S'},
 294                 {"sticky-timeouts",     no_argument,    NULL,   'T'},
 295                 {"3gb",                 no_argument,    NULL,   '3'},
 296                 {"4gb",                 no_argument,    NULL,   OPT_4GB},
 297                 {"uname-2.6",           no_argument,    NULL,   OPT_UNAME26},
 298                 {"list",                no_argument,    NULL,   OPT_LIST},
 299                 {NULL,                  0,              NULL,   0}
 300         };
 301
 302         setlocale(LC_ALL, "");
 303         bindtextdomain(PACKAGE, LOCALEDIR);
 304         textdomain(PACKAGE);
 305         atexit(close_stdout);
 306
 307         if (argc < 1) {
 308                 warnx(_("Not enough arguments"));
 309                 errtryhelp(EXIT_FAILURE);
 310         }
 311         archwrapper = strcmp(program_invocation_short_name, "setarch") != 0;
 312         if (archwrapper) {
 313                 arch = program_invocation_short_name;   /* symlinks to setarch */
 314
 315                 /* Don't use ifdef sparc here, we get "Unrecognized architecture"
 316                  * error message later if necessary */
 317                 if (strcmp(arch, "sparc32bash") == 0) {
 318                         shell = "/bin/bash";
 319                         shell_arg = "";
 320                         goto set_arch;
 321                 }
 322         } else {
 323                 if (1 < argc && *argv[1] != '-') {
 324                         arch = argv[1];
 325                         argv[1] = argv[0];      /* for getopt_long() to get the program name */
 326                         argv++;
 327                         argc--;
 328                 }
 329         }
 330
 331         while ((c = getopt_long(argc, argv, "+hVv3BFILRSTXZ", longopts, NULL)) != -1) {
 332                 switch (c) {
 333                 case 'h':
 334                         usage(archwrapper);
 335                         break;
 336                 case 'V':
 337                         printf(UTIL_LINUX_VERSION);
 338                         return EXIT_SUCCESS;
 339                 case 'v':
 340                         verbose = 1;
 341                         break;
 342                 case 'R':
 343                         turn_on(ADDR_NO_RANDOMIZE, options);
 344                         break;
 345                 case 'F':
 346                         turn_on(FDPIC_FUNCPTRS, options);
 347                         break;
 348                 case 'Z':
 349                         turn_on(MMAP_PAGE_ZERO, options);
 350                         break;
 351                 case 'L':
 352                         turn_on(ADDR_COMPAT_LAYOUT, options);
 353                         break;
 354                 case 'X':
 355                         turn_on(READ_IMPLIES_EXEC, options);
 356                         break;
 357                 case 'B':
 358                         turn_on(ADDR_LIMIT_32BIT, options);
 359                         break;
 360                 case 'I':
 361                         turn_on(SHORT_INODE, options);
 362                         break;
 363                 case 'S':
 364                         turn_on(WHOLE_SECONDS, options);
 365                         break;
 366                 case 'T':
 367                         turn_on(STICKY_TIMEOUTS, options);
 368                         break;
 369                 case '3':
 370                         turn_on(ADDR_LIMIT_3GB, options);
 371                         break;
 372                 case OPT_4GB:   /* just ignore this one */
 373                         break;
 374                 case OPT_UNAME26:
 375                         turn_on(UNAME26, options);
 376                         break;
 377                 case OPT_LIST:
 378                         if (!archwrapper) {
 379                                 list_arch_domains(init_arch_domains());
 380                                 return EXIT_SUCCESS;
 381                         } else
 382                                 warnx(_("unrecognized option '--list'"));
 383                         /* fallthrough */
 384                 default:
 385                         errtryhelp(EXIT_FAILURE);
 386                 }
 387         }
 388
 389         if (!arch && !options)
 390                 errx(EXIT_FAILURE, _("no architecture argument or personality flags specified"));
 391
 392         argc -= optind;
 393         argv += optind;
 394
 395 set_arch:
 396         /* get execution domain (architecture) */
 397         if (arch) {
 398                 doms = init_arch_domains();
 399                 target = get_arch_domain(doms, arch);
 400
 401                 if (!target)
 402                         errx(EXIT_FAILURE, _("%s: Unrecognized architecture"), arch);
 403                 pers_value = target->perval;
 404         }
 405
 406         /* add personality flags */
 407         pers_value |= options;
 408
 409         /* call kernel */
 410         if (personality(pers_value) < 0) {
 411                 /*
 412                  * Depending on architecture and kernel version, personality
 413                  * syscall is either capable or incapable of returning an error.
 414                  * If the return value is not an error, then it's the previous
 415                  * personality value, which can be an arbitrary value
 416                  * undistinguishable from an error value.
 417                  * To make things clear, a second call is needed.
 418                  */
 419                 if (personality(pers_value) < 0)
 420                         err(EXIT_FAILURE, _("failed to set personality to %s"), arch);
 421         }
 422
 423         /* make sure architecture is set as expected */
 424         if (arch)
 425                 verify_arch_domain(target, arch);
 426
 427         if (!argc) {
 428                 shell = "/bin/sh";
 429                 shell_arg = "-sh";
 430         }
 431         if (verbose) {
 432                 printf(_("Execute command `%s'.\n"), shell ? shell : argv[0]);
 433                 /* flush all output streams before exec */
 434                 fflush(NULL);
 435         }
 436
 437         /* Execute shell */
 438         if (shell) {
 439                 execl(shell, shell_arg, NULL);
 440                 errexec(shell);
 441         }
 442
 443         /* Execute on command line specified command */
 444         execvp(argv[0], argv);
 445         errexec(argv[0]);
 446 }