linux-user/main.c

   1 /*
   2  *  qemu user main
   3  *
   4  *  Copyright (c) 2003-2008 Fabrice Bellard
   5  *
   6  *  This program 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 program 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  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include "qemu/osdep.h"
  21 #include "qemu/help-texts.h"
  22 #include "qemu/units.h"
  23 #include "qemu/accel.h"
  24 #include "qemu-version.h"
  25 #include <sys/syscall.h>
  26 #include <sys/resource.h>
  27 #include <sys/shm.h>
  28 #include <linux/binfmts.h>
  29
  30 #include "qapi/error.h"
  31 #include "qemu.h"
  32 #include "user-internals.h"
  33 #include "qemu/path.h"
  34 #include "qemu/queue.h"
  35 #include "qemu/config-file.h"
  36 #include "qemu/cutils.h"
  37 #include "qemu/error-report.h"
  38 #include "qemu/help_option.h"
  39 #include "qemu/module.h"
  40 #include "qemu/plugin.h"
  41 #include "exec/exec-all.h"
  42 #include "exec/gdbstub.h"
  43 #include "tcg/tcg.h"
  44 #include "qemu/timer.h"
  45 #include "qemu/envlist.h"
  46 #include "qemu/guest-random.h"
  47 #include "elf.h"
  48 #include "trace/control.h"
  49 #include "target_elf.h"
  50 #include "cpu_loop-common.h"
  51 #include "crypto/init.h"
  52 #include "fd-trans.h"
  53 #include "signal-common.h"
  54 #include "loader.h"
  55 #include "user-mmap.h"
  56
  57 #ifdef CONFIG_SEMIHOSTING
  58 #include "semihosting/semihost.h"
  59 #endif
  60
  61 #ifndef AT_FLAGS_PRESERVE_ARGV0
  62 #define AT_FLAGS_PRESERVE_ARGV0_BIT 0
  63 #define AT_FLAGS_PRESERVE_ARGV0 (1 << AT_FLAGS_PRESERVE_ARGV0_BIT)
  64 #endif
  65
  66 char *exec_path;
  67
  68 int singlestep;
  69 static const char *argv0;
  70 static const char *gdbstub;
  71 static envlist_t *envlist;
  72 static const char *cpu_model;
  73 static const char *cpu_type;
  74 static const char *seed_optarg;
  75 unsigned long mmap_min_addr;
  76 uintptr_t guest_base;
  77 bool have_guest_base;
  78
  79 /*
  80  * Used to implement backwards-compatibility for the `-strace`, and
  81  * QEMU_STRACE options. Without this, the QEMU_LOG can be overwritten by
  82  * -strace, or vice versa.
  83  */
  84 static bool enable_strace;
  85
  86 /*
  87  * The last log mask given by the user in an environment variable or argument.
  88  * Used to support command line arguments overriding environment variables.
  89  */
  90 static int last_log_mask;
  91 static const char *last_log_filename;
  92
  93 /*
  94  * When running 32-on-64 we should make sure we can fit all of the possible
  95  * guest address space into a contiguous chunk of virtual host memory.
  96  *
  97  * This way we will never overlap with our own libraries or binaries or stack
  98  * or anything else that QEMU maps.
  99  *
 100  * Many cpus reserve the high bit (or more than one for some 64-bit cpus)
 101  * of the address for the kernel.  Some cpus rely on this and user space
 102  * uses the high bit(s) for pointer tagging and the like.  For them, we
 103  * must preserve the expected address space.
 104  */
 105 #ifndef MAX_RESERVED_VA
 106 # if HOST_LONG_BITS > TARGET_VIRT_ADDR_SPACE_BITS
 107 #  if TARGET_VIRT_ADDR_SPACE_BITS == 32 && \
 108       (TARGET_LONG_BITS == 32 || defined(TARGET_ABI32))
 109 /* There are a number of places where we assign reserved_va to a variable
 110    of type abi_ulong and expect it to fit.  Avoid the last page.  */
 111 #   define MAX_RESERVED_VA(CPU)  (0xfffffffful & TARGET_PAGE_MASK)
 112 #  else
 113 #   define MAX_RESERVED_VA(CPU)  (1ul << TARGET_VIRT_ADDR_SPACE_BITS)
 114 #  endif
 115 # else
 116 #  define MAX_RESERVED_VA(CPU)  0
 117 # endif
 118 #endif
 119
 120 unsigned long reserved_va;
 121
 122 static void usage(int exitcode);
 123
 124 static const char *interp_prefix = CONFIG_QEMU_INTERP_PREFIX;
 125 const char *qemu_uname_release;
 126
 127 #if !defined(TARGET_DEFAULT_STACK_SIZE)
 128 /* XXX: on x86 MAP_GROWSDOWN only works if ESP <= address + 32, so
 129    we allocate a bigger stack. Need a better solution, for example
 130    by remapping the process stack directly at the right place */
 131 #define TARGET_DEFAULT_STACK_SIZE       8 * 1024 * 1024UL
 132 #endif
 133
 134 unsigned long guest_stack_size = TARGET_DEFAULT_STACK_SIZE;
 135
 136 /***********************************************************/
 137 /* Helper routines for implementing atomic operations.  */
 138
 139 /* Make sure everything is in a consistent state for calling fork().  */
 140 void fork_start(void)
 141 {
 142     start_exclusive();
 143     mmap_fork_start();
 144     cpu_list_lock();
 145     qemu_plugin_user_prefork_lock();
 146 }
 147
 148 void fork_end(int child)
 149 {
 150     qemu_plugin_user_postfork(child);
 151     mmap_fork_end(child);
 152     if (child) {
 153         CPUState *cpu, *next_cpu;
 154         /* Child processes created by fork() only have a single thread.
 155            Discard information about the parent threads.  */
 156         CPU_FOREACH_SAFE(cpu, next_cpu) {
 157             if (cpu != thread_cpu) {
 158                 QTAILQ_REMOVE_RCU(&cpus, cpu, node);
 159             }
 160         }
 161         qemu_init_cpu_list();
 162         gdbserver_fork(thread_cpu);
 163         /* qemu_init_cpu_list() takes care of reinitializing the
 164          * exclusive state, so we don't need to end_exclusive() here.
 165          */
 166     } else {
 167         cpu_list_unlock();
 168         end_exclusive();
 169     }
 170 }
 171
 172 __thread CPUState *thread_cpu;
 173
 174 bool qemu_cpu_is_self(CPUState *cpu)
 175 {
 176     return thread_cpu == cpu;
 177 }
 178
 179 void qemu_cpu_kick(CPUState *cpu)
 180 {
 181     cpu_exit(cpu);
 182 }
 183
 184 void task_settid(TaskState *ts)
 185 {
 186     if (ts->ts_tid == 0) {
 187         ts->ts_tid = (pid_t)syscall(SYS_gettid);
 188     }
 189 }
 190
 191 void stop_all_tasks(void)
 192 {
 193     /*
 194      * We trust that when using NPTL, start_exclusive()
 195      * handles thread stopping correctly.
 196      */
 197     start_exclusive();
 198 }
 199
 200 /* Assumes contents are already zeroed.  */
 201 void init_task_state(TaskState *ts)
 202 {
 203     long ticks_per_sec;
 204     struct timespec bt;
 205
 206     ts->used = 1;
 207     ts->sigaltstack_used = (struct target_sigaltstack) {
 208         .ss_sp = 0,
 209         .ss_size = 0,
 210         .ss_flags = TARGET_SS_DISABLE,
 211     };
 212
 213     /* Capture task start time relative to system boot */
 214
 215     ticks_per_sec = sysconf(_SC_CLK_TCK);
 216
 217     if ((ticks_per_sec > 0) && !clock_gettime(CLOCK_BOOTTIME, &bt)) {
 218         /* start_boottime is expressed in clock ticks */
 219         ts->start_boottime = bt.tv_sec * (uint64_t) ticks_per_sec;
 220         ts->start_boottime += bt.tv_nsec * (uint64_t) ticks_per_sec /
 221                               NANOSECONDS_PER_SECOND;
 222     }
 223 }
 224
 225 CPUArchState *cpu_copy(CPUArchState *env)
 226 {
 227     CPUState *cpu = env_cpu(env);
 228     CPUState *new_cpu = cpu_create(cpu_type);
 229     CPUArchState *new_env = new_cpu->env_ptr;
 230     CPUBreakpoint *bp;
 231
 232     /* Reset non arch specific state */
 233     cpu_reset(new_cpu);
 234
 235     new_cpu->tcg_cflags = cpu->tcg_cflags;
 236     memcpy(new_env, env, sizeof(CPUArchState));
 237
 238     /* Clone all break/watchpoints.
 239        Note: Once we support ptrace with hw-debug register access, make sure
 240        BP_CPU break/watchpoints are handled correctly on clone. */
 241     QTAILQ_INIT(&new_cpu->breakpoints);
 242     QTAILQ_FOREACH(bp, &cpu->breakpoints, entry) {
 243         cpu_breakpoint_insert(new_cpu, bp->pc, bp->flags, NULL);
 244     }
 245
 246     return new_env;
 247 }
 248
 249 static void handle_arg_help(const char *arg)
 250 {
 251     usage(EXIT_SUCCESS);
 252 }
 253
 254 static void handle_arg_log(const char *arg)
 255 {
 256     last_log_mask = qemu_str_to_log_mask(arg);
 257     if (!last_log_mask) {
 258         qemu_print_log_usage(stdout);
 259         exit(EXIT_FAILURE);
 260     }
 261 }
 262
 263 static void handle_arg_dfilter(const char *arg)
 264 {
 265     qemu_set_dfilter_ranges(arg, &error_fatal);
 266 }
 267
 268 static void handle_arg_log_filename(const char *arg)
 269 {
 270     last_log_filename = arg;
 271 }
 272
 273 static void handle_arg_set_env(const char *arg)
 274 {
 275     char *r, *p, *token;
 276     r = p = strdup(arg);
 277     while ((token = strsep(&p, ",")) != NULL) {
 278         if (envlist_setenv(envlist, token) != 0) {
 279             usage(EXIT_FAILURE);
 280         }
 281     }
 282     free(r);
 283 }
 284
 285 static void handle_arg_unset_env(const char *arg)
 286 {
 287     char *r, *p, *token;
 288     r = p = strdup(arg);
 289     while ((token = strsep(&p, ",")) != NULL) {
 290         if (envlist_unsetenv(envlist, token) != 0) {
 291             usage(EXIT_FAILURE);
 292         }
 293     }
 294     free(r);
 295 }
 296
 297 static void handle_arg_argv0(const char *arg)
 298 {
 299     argv0 = strdup(arg);
 300 }
 301
 302 static void handle_arg_stack_size(const char *arg)
 303 {
 304     char *p;
 305     guest_stack_size = strtoul(arg, &p, 0);
 306     if (guest_stack_size == 0) {
 307         usage(EXIT_FAILURE);
 308     }
 309
 310     if (*p == 'M') {
 311         guest_stack_size *= MiB;
 312     } else if (*p == 'k' || *p == 'K') {
 313         guest_stack_size *= KiB;
 314     }
 315 }
 316
 317 static void handle_arg_ld_prefix(const char *arg)
 318 {
 319     interp_prefix = strdup(arg);
 320 }
 321
 322 static void handle_arg_pagesize(const char *arg)
 323 {
 324     qemu_host_page_size = atoi(arg);
 325     if (qemu_host_page_size == 0 ||
 326         (qemu_host_page_size & (qemu_host_page_size - 1)) != 0) {
 327         fprintf(stderr, "page size must be a power of two\n");
 328         exit(EXIT_FAILURE);
 329     }
 330 }
 331
 332 static void handle_arg_seed(const char *arg)
 333 {
 334     seed_optarg = arg;
 335 }
 336
 337 static void handle_arg_gdb(const char *arg)
 338 {
 339     gdbstub = g_strdup(arg);
 340 }
 341
 342 static void handle_arg_uname(const char *arg)
 343 {
 344     qemu_uname_release = strdup(arg);
 345 }
 346
 347 static void handle_arg_cpu(const char *arg)
 348 {
 349     cpu_model = strdup(arg);
 350     if (cpu_model == NULL || is_help_option(cpu_model)) {
 351         /* XXX: implement xxx_cpu_list for targets that still miss it */
 352 #if defined(cpu_list)
 353         cpu_list();
 354 #endif
 355         exit(EXIT_FAILURE);
 356     }
 357 }
 358
 359 static void handle_arg_guest_base(const char *arg)
 360 {
 361     guest_base = strtol(arg, NULL, 0);
 362     have_guest_base = true;
 363 }
 364
 365 static void handle_arg_reserved_va(const char *arg)
 366 {
 367     char *p;
 368     int shift = 0;
 369     reserved_va = strtoul(arg, &p, 0);
 370     switch (*p) {
 371     case 'k':
 372     case 'K':
 373         shift = 10;
 374         break;
 375     case 'M':
 376         shift = 20;
 377         break;
 378     case 'G':
 379         shift = 30;
 380         break;
 381     }
 382     if (shift) {
 383         unsigned long unshifted = reserved_va;
 384         p++;
 385         reserved_va <<= shift;
 386         if (reserved_va >> shift != unshifted) {
 387             fprintf(stderr, "Reserved virtual address too big\n");
 388             exit(EXIT_FAILURE);
 389         }
 390     }
 391     if (*p) {
 392         fprintf(stderr, "Unrecognised -R size suffix '%s'\n", p);
 393         exit(EXIT_FAILURE);
 394     }
 395 }
 396
 397 static void handle_arg_singlestep(const char *arg)
 398 {
 399     singlestep = 1;
 400 }
 401
 402 static void handle_arg_strace(const char *arg)
 403 {
 404     enable_strace = true;
 405 }
 406
 407 static void handle_arg_version(const char *arg)
 408 {
 409     printf("qemu-" TARGET_NAME " version " QEMU_FULL_VERSION
 410            "\n" QEMU_COPYRIGHT "\n");
 411     exit(EXIT_SUCCESS);
 412 }
 413
 414 static void handle_arg_trace(const char *arg)
 415 {
 416     trace_opt_parse(arg);
 417 }
 418
 419 #if defined(TARGET_XTENSA)
 420 static void handle_arg_abi_call0(const char *arg)
 421 {
 422     xtensa_set_abi_call0();
 423 }
 424 #endif
 425
 426 static QemuPluginList plugins = QTAILQ_HEAD_INITIALIZER(plugins);
 427
 428 #ifdef CONFIG_PLUGIN
 429 static void handle_arg_plugin(const char *arg)
 430 {
 431     qemu_plugin_opt_parse(arg, &plugins);
 432 }
 433 #endif
 434
 435 struct qemu_argument {
 436     const char *argv;
 437     const char *env;
 438     bool has_arg;
 439     void (*handle_opt)(const char *arg);
 440     const char *example;
 441     const char *help;
 442 };
 443
 444 static const struct qemu_argument arg_table[] = {
 445     {"h",          "",                 false, handle_arg_help,
 446      "",           "print this help"},
 447     {"help",       "",                 false, handle_arg_help,
 448      "",           ""},
 449     {"g",          "QEMU_GDB",         true,  handle_arg_gdb,
 450      "port",       "wait gdb connection to 'port'"},
 451     {"L",          "QEMU_LD_PREFIX",   true,  handle_arg_ld_prefix,
 452      "path",       "set the elf interpreter prefix to 'path'"},
 453     {"s",          "QEMU_STACK_SIZE",  true,  handle_arg_stack_size,
 454      "size",       "set the stack size to 'size' bytes"},
 455     {"cpu",        "QEMU_CPU",         true,  handle_arg_cpu,
 456      "model",      "select CPU (-cpu help for list)"},
 457     {"E",          "QEMU_SET_ENV",     true,  handle_arg_set_env,
 458      "var=value",  "sets targets environment variable (see below)"},
 459     {"U",          "QEMU_UNSET_ENV",   true,  handle_arg_unset_env,
 460      "var",        "unsets targets environment variable (see below)"},
 461     {"0",          "QEMU_ARGV0",       true,  handle_arg_argv0,
 462      "argv0",      "forces target process argv[0] to be 'argv0'"},
 463     {"r",          "QEMU_UNAME",       true,  handle_arg_uname,
 464      "uname",      "set qemu uname release string to 'uname'"},
 465     {"B",          "QEMU_GUEST_BASE",  true,  handle_arg_guest_base,
 466      "address",    "set guest_base address to 'address'"},
 467     {"R",          "QEMU_RESERVED_VA", true,  handle_arg_reserved_va,
 468      "size",       "reserve 'size' bytes for guest virtual address space"},
 469     {"d",          "QEMU_LOG",         true,  handle_arg_log,
 470      "item[,...]", "enable logging of specified items "
 471      "(use '-d help' for a list of items)"},
 472     {"dfilter",    "QEMU_DFILTER",     true,  handle_arg_dfilter,
 473      "range[,...]","filter logging based on address range"},
 474     {"D",          "QEMU_LOG_FILENAME", true, handle_arg_log_filename,
 475      "logfile",     "write logs to 'logfile' (default stderr)"},
 476     {"p",          "QEMU_PAGESIZE",    true,  handle_arg_pagesize,
 477      "pagesize",   "set the host page size to 'pagesize'"},
 478     {"singlestep", "QEMU_SINGLESTEP",  false, handle_arg_singlestep,
 479      "",           "run in singlestep mode"},
 480     {"strace",     "QEMU_STRACE",      false, handle_arg_strace,
 481      "",           "log system calls"},
 482     {"seed",       "QEMU_RAND_SEED",   true,  handle_arg_seed,
 483      "",           "Seed for pseudo-random number generator"},
 484     {"trace",      "QEMU_TRACE",       true,  handle_arg_trace,
 485      "",           "[[enable=]<pattern>][,events=<file>][,file=<file>]"},
 486 #ifdef CONFIG_PLUGIN
 487     {"plugin",     "QEMU_PLUGIN",      true,  handle_arg_plugin,
 488      "",           "[file=]<file>[,<argname>=<argvalue>]"},
 489 #endif
 490     {"version",    "QEMU_VERSION",     false, handle_arg_version,
 491      "",           "display version information and exit"},
 492 #if defined(TARGET_XTENSA)
 493     {"xtensa-abi-call0", "QEMU_XTENSA_ABI_CALL0", false, handle_arg_abi_call0,
 494      "",           "assume CALL0 Xtensa ABI"},
 495 #endif
 496     {NULL, NULL, false, NULL, NULL, NULL}
 497 };
 498
 499 static void usage(int exitcode)
 500 {
 501     const struct qemu_argument *arginfo;
 502     int maxarglen;
 503     int maxenvlen;
 504
 505     printf("usage: qemu-" TARGET_NAME " [options] program [arguments...]\n"
 506            "Linux CPU emulator (compiled for " TARGET_NAME " emulation)\n"
 507            "\n"
 508            "Options and associated environment variables:\n"
 509            "\n");
 510
 511     /* Calculate column widths. We must always have at least enough space
 512      * for the column header.
 513      */
 514     maxarglen = strlen("Argument");
 515     maxenvlen = strlen("Env-variable");
 516
 517     for (arginfo = arg_table; arginfo->handle_opt != NULL; arginfo++) {
 518         int arglen = strlen(arginfo->argv);
 519         if (arginfo->has_arg) {
 520             arglen += strlen(arginfo->example) + 1;
 521         }
 522         if (strlen(arginfo->env) > maxenvlen) {
 523             maxenvlen = strlen(arginfo->env);
 524         }
 525         if (arglen > maxarglen) {
 526             maxarglen = arglen;
 527         }
 528     }
 529
 530     printf("%-*s %-*s Description\n", maxarglen+1, "Argument",
 531             maxenvlen, "Env-variable");
 532
 533     for (arginfo = arg_table; arginfo->handle_opt != NULL; arginfo++) {
 534         if (arginfo->has_arg) {
 535             printf("-%s %-*s %-*s %s\n", arginfo->argv,
 536                    (int)(maxarglen - strlen(arginfo->argv) - 1),
 537                    arginfo->example, maxenvlen, arginfo->env, arginfo->help);
 538         } else {
 539             printf("-%-*s %-*s %s\n", maxarglen, arginfo->argv,
 540                     maxenvlen, arginfo->env,
 541                     arginfo->help);
 542         }
 543     }
 544
 545     printf("\n"
 546            "Defaults:\n"
 547            "QEMU_LD_PREFIX  = %s\n"
 548            "QEMU_STACK_SIZE = %ld byte\n",
 549            interp_prefix,
 550            guest_stack_size);
 551
 552     printf("\n"
 553            "You can use -E and -U options or the QEMU_SET_ENV and\n"
 554            "QEMU_UNSET_ENV environment variables to set and unset\n"
 555            "environment variables for the target process.\n"
 556            "It is possible to provide several variables by separating them\n"
 557            "by commas in getsubopt(3) style. Additionally it is possible to\n"
 558            "provide the -E and -U options multiple times.\n"
 559            "The following lines are equivalent:\n"
 560            "    -E var1=val2 -E var2=val2 -U LD_PRELOAD -U LD_DEBUG\n"
 561            "    -E var1=val2,var2=val2 -U LD_PRELOAD,LD_DEBUG\n"
 562            "    QEMU_SET_ENV=var1=val2,var2=val2 QEMU_UNSET_ENV=LD_PRELOAD,LD_DEBUG\n"
 563            "Note that if you provide several changes to a single variable\n"
 564            "the last change will stay in effect.\n"
 565            "\n"
 566            QEMU_HELP_BOTTOM "\n");
 567
 568     exit(exitcode);
 569 }
 570
 571 static int parse_args(int argc, char **argv)
 572 {
 573     const char *r;
 574     int optind;
 575     const struct qemu_argument *arginfo;
 576
 577     for (arginfo = arg_table; arginfo->handle_opt != NULL; arginfo++) {
 578         if (arginfo->env == NULL) {
 579             continue;
 580         }
 581
 582         r = getenv(arginfo->env);
 583         if (r != NULL) {
 584             arginfo->handle_opt(r);
 585         }
 586     }
 587
 588     optind = 1;
 589     for (;;) {
 590         if (optind >= argc) {
 591             break;
 592         }
 593         r = argv[optind];
 594         if (r[0] != '-') {
 595             break;
 596         }
 597         optind++;
 598         r++;
 599         if (!strcmp(r, "-")) {
 600             break;
 601         }
 602         /* Treat --foo the same as -foo.  */
 603         if (r[0] == '-') {
 604             r++;
 605         }
 606
 607         for (arginfo = arg_table; arginfo->handle_opt != NULL; arginfo++) {
 608             if (!strcmp(r, arginfo->argv)) {
 609                 if (arginfo->has_arg) {
 610                     if (optind >= argc) {
 611                         (void) fprintf(stderr,
 612                             "qemu: missing argument for option '%s'\n", r);
 613                         exit(EXIT_FAILURE);
 614                     }
 615                     arginfo->handle_opt(argv[optind]);
 616                     optind++;
 617                 } else {
 618                     arginfo->handle_opt(NULL);
 619                 }
 620                 break;
 621             }
 622         }
 623
 624         /* no option matched the current argv */
 625         if (arginfo->handle_opt == NULL) {
 626             (void) fprintf(stderr, "qemu: unknown option '%s'\n", r);
 627             exit(EXIT_FAILURE);
 628         }
 629     }
 630
 631     if (optind >= argc) {
 632         (void) fprintf(stderr, "qemu: no user program specified\n");
 633         exit(EXIT_FAILURE);
 634     }
 635
 636     exec_path = argv[optind];
 637
 638     return optind;
 639 }
 640
 641 int main(int argc, char **argv, char **envp)
 642 {
 643     struct target_pt_regs regs1, *regs = &regs1;
 644     struct image_info info1, *info = &info1;
 645     struct linux_binprm bprm;
 646     TaskState *ts;
 647     CPUArchState *env;
 648     CPUState *cpu;
 649     int optind;
 650     char **target_environ, **wrk;
 651     char **target_argv;
 652     int target_argc;
 653     int i;
 654     int ret;
 655     int execfd;
 656     unsigned long max_reserved_va;
 657     bool preserve_argv0;
 658
 659     error_init(argv[0]);
 660     module_call_init(MODULE_INIT_TRACE);
 661     qemu_init_cpu_list();
 662     module_call_init(MODULE_INIT_QOM);
 663
 664     envlist = envlist_create();
 665
 666     /* add current environment into the list */
 667     for (wrk = environ; *wrk != NULL; wrk++) {
 668         (void) envlist_setenv(envlist, *wrk);
 669     }
 670
 671     /* Read the stack limit from the kernel.  If it's "unlimited",
 672        then we can do little else besides use the default.  */
 673     {
 674         struct rlimit lim;
 675         if (getrlimit(RLIMIT_STACK, &lim) == 0
 676             && lim.rlim_cur != RLIM_INFINITY
 677             && lim.rlim_cur == (target_long)lim.rlim_cur
 678             && lim.rlim_cur > guest_stack_size) {
 679             guest_stack_size = lim.rlim_cur;
 680         }
 681     }
 682
 683     cpu_model = NULL;
 684
 685     qemu_add_opts(&qemu_trace_opts);
 686     qemu_plugin_add_opts();
 687
 688     optind = parse_args(argc, argv);
 689
 690     qemu_set_log_filename_flags(last_log_filename,
 691                                 last_log_mask | (enable_strace * LOG_STRACE),
 692                                 &error_fatal);
 693
 694     if (!trace_init_backends()) {
 695         exit(1);
 696     }
 697     trace_init_file();
 698     qemu_plugin_load_list(&plugins, &error_fatal);
 699
 700     /* Zero out regs */
 701     memset(regs, 0, sizeof(struct target_pt_regs));
 702
 703     /* Zero out image_info */
 704     memset(info, 0, sizeof(struct image_info));
 705
 706     memset(&bprm, 0, sizeof (bprm));
 707
 708     /* Scan interp_prefix dir for replacement files. */
 709     init_paths(interp_prefix);
 710
 711     init_qemu_uname_release();
 712
 713     /*
 714      * Manage binfmt-misc open-binary flag
 715      */
 716     execfd = qemu_getauxval(AT_EXECFD);
 717     if (execfd == 0) {
 718         execfd = open(exec_path, O_RDONLY);
 719         if (execfd < 0) {
 720             printf("Error while loading %s: %s\n", exec_path, strerror(errno));
 721             _exit(EXIT_FAILURE);
 722         }
 723     }
 724
 725     /*
 726      * get binfmt_misc flags
 727      */
 728     preserve_argv0 = !!(qemu_getauxval(AT_FLAGS) & AT_FLAGS_PRESERVE_ARGV0);
 729
 730     /*
 731      * Manage binfmt-misc preserve-arg[0] flag
 732      *    argv[optind]     full path to the binary
 733      *    argv[optind + 1] original argv[0]
 734      */
 735     if (optind + 1 < argc && preserve_argv0) {
 736         optind++;
 737     }
 738
 739     if (cpu_model == NULL) {
 740         cpu_model = cpu_get_model(get_elf_eflags(execfd));
 741     }
 742     cpu_type = parse_cpu_option(cpu_model);
 743
 744     /* init tcg before creating CPUs and to get qemu_host_page_size */
 745     {
 746         AccelClass *ac = ACCEL_GET_CLASS(current_accel());
 747
 748         accel_init_interfaces(ac);
 749         ac->init_machine(NULL);
 750     }
 751     cpu = cpu_create(cpu_type);
 752     env = cpu->env_ptr;
 753     cpu_reset(cpu);
 754     thread_cpu = cpu;
 755
 756     /*
 757      * Reserving too much vm space via mmap can run into problems
 758      * with rlimits, oom due to page table creation, etc.  We will
 759      * still try it, if directed by the command-line option, but
 760      * not by default.
 761      */
 762     max_reserved_va = MAX_RESERVED_VA(cpu);
 763     if (reserved_va != 0) {
 764         if (max_reserved_va && reserved_va > max_reserved_va) {
 765             fprintf(stderr, "Reserved virtual address too big\n");
 766             exit(EXIT_FAILURE);
 767         }
 768     } else if (HOST_LONG_BITS == 64 && TARGET_VIRT_ADDR_SPACE_BITS <= 32) {
 769         /*
 770          * reserved_va must be aligned with the host page size
 771          * as it is used with mmap()
 772          */
 773         reserved_va = max_reserved_va & qemu_host_page_mask;
 774     }
 775
 776     {
 777         Error *err = NULL;
 778         if (seed_optarg != NULL) {
 779             qemu_guest_random_seed_main(seed_optarg, &err);
 780         } else {
 781             qcrypto_init(&err);
 782         }
 783         if (err) {
 784             error_reportf_err(err, "cannot initialize crypto: ");
 785             exit(1);
 786         }
 787     }
 788
 789     target_environ = envlist_to_environ(envlist, NULL);
 790     envlist_free(envlist);
 791
 792     /*
 793      * Read in mmap_min_addr kernel parameter.  This value is used
 794      * When loading the ELF image to determine whether guest_base
 795      * is needed.  It is also used in mmap_find_vma.
 796      */
 797     {
 798         FILE *fp;
 799
 800         if ((fp = fopen("/proc/sys/vm/mmap_min_addr", "r")) != NULL) {
 801             unsigned long tmp;
 802             if (fscanf(fp, "%lu", &tmp) == 1 && tmp != 0) {
 803                 mmap_min_addr = tmp;
 804                 qemu_log_mask(CPU_LOG_PAGE, "host mmap_min_addr=0x%lx\n",
 805                               mmap_min_addr);
 806             }
 807             fclose(fp);
 808         }
 809     }
 810
 811     /*
 812      * We prefer to not make NULL pointers accessible to QEMU.
 813      * If we're in a chroot with no /proc, fall back to 1 page.
 814      */
 815     if (mmap_min_addr == 0) {
 816         mmap_min_addr = qemu_host_page_size;
 817         qemu_log_mask(CPU_LOG_PAGE,
 818                       "host mmap_min_addr=0x%lx (fallback)\n",
 819                       mmap_min_addr);
 820     }
 821
 822     /*
 823      * Prepare copy of argv vector for target.
 824      */
 825     target_argc = argc - optind;
 826     target_argv = calloc(target_argc + 1, sizeof (char *));
 827     if (target_argv == NULL) {
 828         (void) fprintf(stderr, "Unable to allocate memory for target_argv\n");
 829         exit(EXIT_FAILURE);
 830     }
 831
 832     /*
 833      * If argv0 is specified (using '-0' switch) we replace
 834      * argv[0] pointer with the given one.
 835      */
 836     i = 0;
 837     if (argv0 != NULL) {
 838         target_argv[i++] = strdup(argv0);
 839     }
 840     for (; i < target_argc; i++) {
 841         target_argv[i] = strdup(argv[optind + i]);
 842     }
 843     target_argv[target_argc] = NULL;
 844
 845     ts = g_new0(TaskState, 1);
 846     init_task_state(ts);
 847     /* build Task State */
 848     ts->info = info;
 849     ts->bprm = &bprm;
 850     cpu->opaque = ts;
 851     task_settid(ts);
 852
 853     fd_trans_init();
 854
 855     ret = loader_exec(execfd, exec_path, target_argv, target_environ, regs,
 856         info, &bprm);
 857     if (ret != 0) {
 858         printf("Error while loading %s: %s\n", exec_path, strerror(-ret));
 859         _exit(EXIT_FAILURE);
 860     }
 861
 862     for (wrk = target_environ; *wrk; wrk++) {
 863         g_free(*wrk);
 864     }
 865
 866     g_free(target_environ);
 867
 868     if (qemu_loglevel_mask(CPU_LOG_PAGE)) {
 869         FILE *f = qemu_log_trylock();
 870         if (f) {
 871             fprintf(f, "guest_base  %p\n", (void *)guest_base);
 872             fprintf(f, "page layout changed following binary load\n");
 873             page_dump(f);
 874
 875             fprintf(f, "start_brk   0x" TARGET_ABI_FMT_lx "\n",
 876                     info->start_brk);
 877             fprintf(f, "end_code    0x" TARGET_ABI_FMT_lx "\n",
 878                     info->end_code);
 879             fprintf(f, "start_code  0x" TARGET_ABI_FMT_lx "\n",
 880                     info->start_code);
 881             fprintf(f, "start_data  0x" TARGET_ABI_FMT_lx "\n",
 882                     info->start_data);
 883             fprintf(f, "end_data    0x" TARGET_ABI_FMT_lx "\n",
 884                     info->end_data);
 885             fprintf(f, "start_stack 0x" TARGET_ABI_FMT_lx "\n",
 886                     info->start_stack);
 887             fprintf(f, "brk         0x" TARGET_ABI_FMT_lx "\n",
 888                     info->brk);
 889             fprintf(f, "entry       0x" TARGET_ABI_FMT_lx "\n",
 890                     info->entry);
 891             fprintf(f, "argv_start  0x" TARGET_ABI_FMT_lx "\n",
 892                     info->argv);
 893             fprintf(f, "env_start   0x" TARGET_ABI_FMT_lx "\n",
 894                     info->envp);
 895             fprintf(f, "auxv_start  0x" TARGET_ABI_FMT_lx "\n",
 896                     info->saved_auxv);
 897             qemu_log_unlock(f);
 898         }
 899     }
 900
 901     target_set_brk(info->brk);
 902     syscall_init();
 903     signal_init();
 904
 905     /* Now that we've loaded the binary, GUEST_BASE is fixed.  Delay
 906        generating the prologue until now so that the prologue can take
 907        the real value of GUEST_BASE into account.  */
 908     tcg_prologue_init(tcg_ctx);
 909
 910     target_cpu_copy_regs(env, regs);
 911
 912     if (gdbstub) {
 913         if (gdbserver_start(gdbstub) < 0) {
 914             fprintf(stderr, "qemu: could not open gdbserver on %s\n",
 915                     gdbstub);
 916             exit(EXIT_FAILURE);
 917         }
 918         gdb_handlesig(cpu, 0);
 919     }
 920
 921 #ifdef CONFIG_SEMIHOSTING
 922     qemu_semihosting_guestfd_init();
 923 #endif
 924
 925     cpu_loop(env);
 926     /* never exits */
 927     return 0;
 928 }