include/qemu/osdep.h

   1 /*
   2  * OS includes and handling of OS dependencies
   3  *
   4  * This header exists to pull in some common system headers that
   5  * most code in QEMU will want, and to fix up some possible issues with
   6  * it (missing defines, Windows weirdness, and so on).
   7  *
   8  * To avoid getting into possible circular include dependencies, this
   9  * file should not include any other QEMU headers, with the exceptions
  10  * of config-host.h, config-target.h, qemu/compiler.h,
  11  * sysemu/os-posix.h, sysemu/os-win32.h, glib-compat.h and
  12  * qemu/typedefs.h, all of which are doing a similar job to this file
  13  * and are under similar constraints.
  14  *
  15  * This header also contains prototypes for functions defined in
  16  * os-*.c and util/oslib-*.c; those would probably be better split
  17  * out into separate header files.
  18  *
  19  * In an ideal world this header would contain only:
  20  *  (1) things which everybody needs
  21  *  (2) things without which code would work on most platforms but
  22  *      fail to compile or misbehave on a minority of host OSes
  23  *
  24  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  25  * See the COPYING file in the top-level directory.
  26  */
  27 #ifndef QEMU_OSDEP_H
  28 #define QEMU_OSDEP_H
  29
  30 #include "config-host.h"
  31 #ifdef NEED_CPU_H
  32 #include CONFIG_TARGET
  33 #else
  34 #include "exec/poison.h"
  35 #endif
  36
  37 #include "qemu/compiler.h"
  38
  39 /* Older versions of C++ don't get definitions of various macros from
  40  * stdlib.h unless we define these macros before first inclusion of
  41  * that system header.
  42  */
  43 #ifndef __STDC_CONSTANT_MACROS
  44 #define __STDC_CONSTANT_MACROS
  45 #endif
  46 #ifndef __STDC_LIMIT_MACROS
  47 #define __STDC_LIMIT_MACROS
  48 #endif
  49 #ifndef __STDC_FORMAT_MACROS
  50 #define __STDC_FORMAT_MACROS
  51 #endif
  52
  53 /* The following block of code temporarily renames the daemon() function so the
  54  * compiler does not see the warning associated with it in stdlib.h on OSX
  55  */
  56 #ifdef __APPLE__
  57 #define daemon qemu_fake_daemon_function
  58 #include <stdlib.h>
  59 #undef daemon
  60 extern int daemon(int, int);
  61 #endif
  62
  63 #ifdef _WIN32
  64 /* as defined in sdkddkver.h */
  65 #ifndef _WIN32_WINNT
  66 #define _WIN32_WINNT 0x0600 /* Vista */
  67 #endif
  68 /* reduces the number of implicitly included headers */
  69 #ifndef WIN32_LEAN_AND_MEAN
  70 #define WIN32_LEAN_AND_MEAN
  71 #endif
  72 #endif
  73
  74 /* enable C99/POSIX format strings (needs mingw32-runtime 3.15 or later) */
  75 #ifdef __MINGW32__
  76 #define __USE_MINGW_ANSI_STDIO 1
  77 #endif
  78
  79 #include <stdarg.h>
  80 #include <stddef.h>
  81 #include <stdbool.h>
  82 #include <stdint.h>
  83 #include <sys/types.h>
  84 #include <stdlib.h>
  85 #include <stdio.h>
  86
  87 #include <string.h>
  88 #include <strings.h>
  89 #include <inttypes.h>
  90 #include <limits.h>
  91 /* Put unistd.h before time.h as that triggers localtime_r/gmtime_r
  92  * function availability on recentish Mingw-w64 platforms. */
  93 #include <unistd.h>
  94 #include <time.h>
  95 #include <ctype.h>
  96 #include <errno.h>
  97 #include <fcntl.h>
  98 #include <getopt.h>
  99 #include <sys/stat.h>
 100 #include <sys/time.h>
 101 #include <assert.h>
 102 /* setjmp must be declared before sysemu/os-win32.h
 103  * because it is redefined there. */
 104 #include <setjmp.h>
 105 #include <signal.h>
 106
 107 #ifndef _WIN32
 108 #include <sys/wait.h>
 109 #else
 110 #define WIFEXITED(x)   1
 111 #define WEXITSTATUS(x) (x)
 112 #endif
 113
 114 #ifdef _WIN32
 115 #include "sysemu/os-win32.h"
 116 #endif
 117
 118 #ifdef CONFIG_POSIX
 119 #include "sysemu/os-posix.h"
 120 #endif
 121
 122 #ifdef __APPLE__
 123 #include <AvailabilityMacros.h>
 124 #endif
 125
 126 #include "glib-compat.h"
 127 #include "qemu/typedefs.h"
 128
 129 /*
 130  * For mingw, as of v6.0.0, the function implementing the assert macro is
 131  * not marked as noreturn, so the compiler cannot delete code following an
 132  * assert(false) as unused.  We rely on this within the code base to delete
 133  * code that is unreachable when features are disabled.
 134  * All supported versions of Glib's g_assert() satisfy this requirement.
 135  */
 136 #ifdef __MINGW32__
 137 #undef assert
 138 #define assert(x)  g_assert(x)
 139 #endif
 140
 141 /*
 142  * According to waitpid man page:
 143  * WCOREDUMP
 144  *  This  macro  is  not  specified  in POSIX.1-2001 and is not
 145  *  available on some UNIX implementations (e.g., AIX, SunOS).
 146  *  Therefore, enclose its use inside #ifdef WCOREDUMP ... #endif.
 147  */
 148 #ifndef WCOREDUMP
 149 #define WCOREDUMP(status) 0
 150 #endif
 151 /*
 152  * We have a lot of unaudited code that may fail in strange ways, or
 153  * even be a security risk during migration, if you disable assertions
 154  * at compile-time.  You may comment out these safety checks if you
 155  * absolutely want to disable assertion overhead, but it is not
 156  * supported upstream so the risk is all yours.  Meanwhile, please
 157  * submit patches to remove any side-effects inside an assertion, or
 158  * fixing error handling that should use Error instead of assert.
 159  */
 160 #ifdef NDEBUG
 161 #error building with NDEBUG is not supported
 162 #endif
 163 #ifdef G_DISABLE_ASSERT
 164 #error building with G_DISABLE_ASSERT is not supported
 165 #endif
 166
 167 #ifndef O_LARGEFILE
 168 #define O_LARGEFILE 0
 169 #endif
 170 #ifndef O_BINARY
 171 #define O_BINARY 0
 172 #endif
 173 #ifndef MAP_ANONYMOUS
 174 #define MAP_ANONYMOUS MAP_ANON
 175 #endif
 176 #ifndef MAP_FIXED_NOREPLACE
 177 #define MAP_FIXED_NOREPLACE 0
 178 #endif
 179 #ifndef ENOMEDIUM
 180 #define ENOMEDIUM ENODEV
 181 #endif
 182 #if !defined(ENOTSUP)
 183 #define ENOTSUP 4096
 184 #endif
 185 #if !defined(ECANCELED)
 186 #define ECANCELED 4097
 187 #endif
 188 #if !defined(EMEDIUMTYPE)
 189 #define EMEDIUMTYPE 4098
 190 #endif
 191 #if !defined(ESHUTDOWN)
 192 #define ESHUTDOWN 4099
 193 #endif
 194
 195 /* time_t may be either 32 or 64 bits depending on the host OS, and
 196  * can be either signed or unsigned, so we can't just hardcode a
 197  * specific maximum value. This is not a C preprocessor constant,
 198  * so you can't use TIME_MAX in an #ifdef, but for our purposes
 199  * this isn't a problem.
 200  */
 201
 202 /* The macros TYPE_SIGNED, TYPE_WIDTH, and TYPE_MAXIMUM are from
 203  * Gnulib, and are under the LGPL v2.1 or (at your option) any
 204  * later version.
 205  */
 206
 207 /* True if the real type T is signed.  */
 208 #define TYPE_SIGNED(t) (!((t)0 < (t)-1))
 209
 210 /* The width in bits of the integer type or expression T.
 211  * Padding bits are not supported.
 212  */
 213 #define TYPE_WIDTH(t) (sizeof(t) * CHAR_BIT)
 214
 215 /* The maximum and minimum values for the integer type T.  */
 216 #define TYPE_MAXIMUM(t)                                                \
 217   ((t) (!TYPE_SIGNED(t)                                                \
 218         ? (t)-1                                                        \
 219         : ((((t)1 << (TYPE_WIDTH(t) - 2)) - 1) * 2 + 1)))
 220
 221 #ifndef TIME_MAX
 222 #define TIME_MAX TYPE_MAXIMUM(time_t)
 223 #endif
 224
 225 /* HOST_LONG_BITS is the size of a native pointer in bits. */
 226 #if UINTPTR_MAX == UINT32_MAX
 227 # define HOST_LONG_BITS 32
 228 #elif UINTPTR_MAX == UINT64_MAX
 229 # define HOST_LONG_BITS 64
 230 #else
 231 # error Unknown pointer size
 232 #endif
 233
 234 /* Mac OSX has a <stdint.h> bug that incorrectly defines SIZE_MAX with
 235  * the wrong type. Our replacement isn't usable in preprocessor
 236  * expressions, but it is sufficient for our needs. */
 237 #if defined(HAVE_BROKEN_SIZE_MAX) && HAVE_BROKEN_SIZE_MAX
 238 #undef SIZE_MAX
 239 #define SIZE_MAX ((size_t)-1)
 240 #endif
 241
 242 /*
 243  * Two variations of MIN/MAX macros. The first is for runtime use, and
 244  * evaluates arguments only once (so it is safe even with side
 245  * effects), but will not work in constant contexts (such as array
 246  * size declarations) because of the '{}'.  The second is for constant
 247  * expression use, where evaluating arguments twice is safe because
 248  * the result is going to be constant anyway, but will not work in a
 249  * runtime context because of a void expression where a value is
 250  * expected.  Thus, both gcc and clang will fail to compile if you use
 251  * the wrong macro (even if the error may seem a bit cryptic).
 252  *
 253  * Note that neither form is usable as an #if condition; if you truly
 254  * need to write conditional code that depends on a minimum or maximum
 255  * determined by the pre-processor instead of the compiler, you'll
 256  * have to open-code it.  Sadly, Coverity is severely confused by the
 257  * constant variants, so we have to dumb things down there.
 258  */
 259 #undef MIN
 260 #define MIN(a, b)                                       \
 261     ({                                                  \
 262         typeof(1 ? (a) : (b)) _a = (a), _b = (b);       \
 263         _a < _b ? _a : _b;                              \
 264     })
 265 #undef MAX
 266 #define MAX(a, b)                                       \
 267     ({                                                  \
 268         typeof(1 ? (a) : (b)) _a = (a), _b = (b);       \
 269         _a > _b ? _a : _b;                              \
 270     })
 271
 272 #ifdef __COVERITY__
 273 # define MIN_CONST(a, b) ((a) < (b) ? (a) : (b))
 274 # define MAX_CONST(a, b) ((a) > (b) ? (a) : (b))
 275 #else
 276 # define MIN_CONST(a, b)                                        \
 277     __builtin_choose_expr(                                      \
 278         __builtin_constant_p(a) && __builtin_constant_p(b),     \
 279         (a) < (b) ? (a) : (b),                                  \
 280         ((void)0))
 281 # define MAX_CONST(a, b)                                        \
 282     __builtin_choose_expr(                                      \
 283         __builtin_constant_p(a) && __builtin_constant_p(b),     \
 284         (a) > (b) ? (a) : (b),                                  \
 285         ((void)0))
 286 #endif
 287
 288 /*
 289  * Minimum function that returns zero only if both values are zero.
 290  * Intended for use with unsigned values only.
 291  */
 292 #ifndef MIN_NON_ZERO
 293 #define MIN_NON_ZERO(a, b)                              \
 294     ({                                                  \
 295         typeof(1 ? (a) : (b)) _a = (a), _b = (b);       \
 296         _a == 0 ? _b : (_b == 0 || _b > _a) ? _a : _b;  \
 297     })
 298 #endif
 299
 300 /* Round number down to multiple */
 301 #define QEMU_ALIGN_DOWN(n, m) ((n) / (m) * (m))
 302
 303 /* Round number up to multiple. Safe when m is not a power of 2 (see
 304  * ROUND_UP for a faster version when a power of 2 is guaranteed) */
 305 #define QEMU_ALIGN_UP(n, m) QEMU_ALIGN_DOWN((n) + (m) - 1, (m))
 306
 307 /* Check if n is a multiple of m */
 308 #define QEMU_IS_ALIGNED(n, m) (((n) % (m)) == 0)
 309
 310 /* n-byte align pointer down */
 311 #define QEMU_ALIGN_PTR_DOWN(p, n) \
 312     ((typeof(p))QEMU_ALIGN_DOWN((uintptr_t)(p), (n)))
 313
 314 /* n-byte align pointer up */
 315 #define QEMU_ALIGN_PTR_UP(p, n) \
 316     ((typeof(p))QEMU_ALIGN_UP((uintptr_t)(p), (n)))
 317
 318 /* Check if pointer p is n-bytes aligned */
 319 #define QEMU_PTR_IS_ALIGNED(p, n) QEMU_IS_ALIGNED((uintptr_t)(p), (n))
 320
 321 /* Round number up to multiple. Requires that d be a power of 2 (see
 322  * QEMU_ALIGN_UP for a safer but slower version on arbitrary
 323  * numbers); works even if d is a smaller type than n.  */
 324 #ifndef ROUND_UP
 325 #define ROUND_UP(n, d) (((n) + (d) - 1) & -(0 ? (n) : (d)))
 326 #endif
 327
 328 #ifndef DIV_ROUND_UP
 329 #define DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d))
 330 #endif
 331
 332 /*
 333  * &(x)[0] is always a pointer - if it's same type as x then the argument is a
 334  * pointer, not an array.
 335  */
 336 #define QEMU_IS_ARRAY(x) (!__builtin_types_compatible_p(typeof(x), \
 337                                                         typeof(&(x)[0])))
 338 #ifndef ARRAY_SIZE
 339 #define ARRAY_SIZE(x) ((sizeof(x) / sizeof((x)[0])) + \
 340                        QEMU_BUILD_BUG_ON_ZERO(!QEMU_IS_ARRAY(x)))
 341 #endif
 342
 343 int qemu_daemon(int nochdir, int noclose);
 344 void *qemu_try_memalign(size_t alignment, size_t size);
 345 void *qemu_memalign(size_t alignment, size_t size);
 346 void *qemu_anon_ram_alloc(size_t size, uint64_t *align, bool shared);
 347 void qemu_vfree(void *ptr);
 348 void qemu_anon_ram_free(void *ptr, size_t size);
 349
 350 #define QEMU_MADV_INVALID -1
 351
 352 #if defined(CONFIG_MADVISE)
 353
 354 #define QEMU_MADV_WILLNEED  MADV_WILLNEED
 355 #define QEMU_MADV_DONTNEED  MADV_DONTNEED
 356 #ifdef MADV_DONTFORK
 357 #define QEMU_MADV_DONTFORK  MADV_DONTFORK
 358 #else
 359 #define QEMU_MADV_DONTFORK  QEMU_MADV_INVALID
 360 #endif
 361 #ifdef MADV_MERGEABLE
 362 #define QEMU_MADV_MERGEABLE MADV_MERGEABLE
 363 #else
 364 #define QEMU_MADV_MERGEABLE QEMU_MADV_INVALID
 365 #endif
 366 #ifdef MADV_UNMERGEABLE
 367 #define QEMU_MADV_UNMERGEABLE MADV_UNMERGEABLE
 368 #else
 369 #define QEMU_MADV_UNMERGEABLE QEMU_MADV_INVALID
 370 #endif
 371 #ifdef MADV_DODUMP
 372 #define QEMU_MADV_DODUMP MADV_DODUMP
 373 #else
 374 #define QEMU_MADV_DODUMP QEMU_MADV_INVALID
 375 #endif
 376 #ifdef MADV_DONTDUMP
 377 #define QEMU_MADV_DONTDUMP MADV_DONTDUMP
 378 #else
 379 #define QEMU_MADV_DONTDUMP QEMU_MADV_INVALID
 380 #endif
 381 #ifdef MADV_HUGEPAGE
 382 #define QEMU_MADV_HUGEPAGE MADV_HUGEPAGE
 383 #else
 384 #define QEMU_MADV_HUGEPAGE QEMU_MADV_INVALID
 385 #endif
 386 #ifdef MADV_NOHUGEPAGE
 387 #define QEMU_MADV_NOHUGEPAGE MADV_NOHUGEPAGE
 388 #else
 389 #define QEMU_MADV_NOHUGEPAGE QEMU_MADV_INVALID
 390 #endif
 391 #ifdef MADV_REMOVE
 392 #define QEMU_MADV_REMOVE MADV_REMOVE
 393 #else
 394 #define QEMU_MADV_REMOVE QEMU_MADV_INVALID
 395 #endif
 396
 397 #elif defined(CONFIG_POSIX_MADVISE)
 398
 399 #define QEMU_MADV_WILLNEED  POSIX_MADV_WILLNEED
 400 #define QEMU_MADV_DONTNEED  POSIX_MADV_DONTNEED
 401 #define QEMU_MADV_DONTFORK  QEMU_MADV_INVALID
 402 #define QEMU_MADV_MERGEABLE QEMU_MADV_INVALID
 403 #define QEMU_MADV_UNMERGEABLE QEMU_MADV_INVALID
 404 #define QEMU_MADV_DODUMP QEMU_MADV_INVALID
 405 #define QEMU_MADV_DONTDUMP QEMU_MADV_INVALID
 406 #define QEMU_MADV_HUGEPAGE  QEMU_MADV_INVALID
 407 #define QEMU_MADV_NOHUGEPAGE  QEMU_MADV_INVALID
 408 #define QEMU_MADV_REMOVE QEMU_MADV_INVALID
 409
 410 #else /* no-op */
 411
 412 #define QEMU_MADV_WILLNEED  QEMU_MADV_INVALID
 413 #define QEMU_MADV_DONTNEED  QEMU_MADV_INVALID
 414 #define QEMU_MADV_DONTFORK  QEMU_MADV_INVALID
 415 #define QEMU_MADV_MERGEABLE QEMU_MADV_INVALID
 416 #define QEMU_MADV_UNMERGEABLE QEMU_MADV_INVALID
 417 #define QEMU_MADV_DODUMP QEMU_MADV_INVALID
 418 #define QEMU_MADV_DONTDUMP QEMU_MADV_INVALID
 419 #define QEMU_MADV_HUGEPAGE  QEMU_MADV_INVALID
 420 #define QEMU_MADV_NOHUGEPAGE  QEMU_MADV_INVALID
 421 #define QEMU_MADV_REMOVE QEMU_MADV_INVALID
 422
 423 #endif
 424
 425 #ifdef _WIN32
 426 #define HAVE_CHARDEV_SERIAL 1
 427 #elif defined(__linux__) || defined(__sun__) || defined(__FreeBSD__)    \
 428     || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) \
 429     || defined(__GLIBC__) || defined(__APPLE__)
 430 #define HAVE_CHARDEV_SERIAL 1
 431 #endif
 432
 433 #if defined(__linux__) || defined(__FreeBSD__) ||               \
 434     defined(__FreeBSD_kernel__) || defined(__DragonFly__)
 435 #define HAVE_CHARDEV_PARPORT 1
 436 #endif
 437
 438 #if defined(__HAIKU__)
 439 #define SIGIO SIGPOLL
 440 #endif
 441
 442 #if defined(CONFIG_LINUX)
 443 #ifndef BUS_MCEERR_AR
 444 #define BUS_MCEERR_AR 4
 445 #endif
 446 #ifndef BUS_MCEERR_AO
 447 #define BUS_MCEERR_AO 5
 448 #endif
 449 #endif
 450
 451 #if defined(__linux__) && \
 452     (defined(__x86_64__) || defined(__arm__) || defined(__aarch64__) \
 453      || defined(__powerpc64__))
 454    /* Use 2 MiB alignment so transparent hugepages can be used by KVM.
 455       Valgrind does not support alignments larger than 1 MiB,
 456       therefore we need special code which handles running on Valgrind. */
 457 #  define QEMU_VMALLOC_ALIGN (512 * 4096)
 458 #elif defined(__linux__) && defined(__s390x__)
 459    /* Use 1 MiB (segment size) alignment so gmap can be used by KVM. */
 460 #  define QEMU_VMALLOC_ALIGN (256 * 4096)
 461 #elif defined(__linux__) && defined(__sparc__)
 462 #include <sys/shm.h>
 463 #  define QEMU_VMALLOC_ALIGN MAX(qemu_real_host_page_size, SHMLBA)
 464 #else
 465 #  define QEMU_VMALLOC_ALIGN qemu_real_host_page_size
 466 #endif
 467
 468 #ifdef CONFIG_POSIX
 469 struct qemu_signalfd_siginfo {
 470     uint32_t ssi_signo;   /* Signal number */
 471     int32_t  ssi_errno;   /* Error number (unused) */
 472     int32_t  ssi_code;    /* Signal code */
 473     uint32_t ssi_pid;     /* PID of sender */
 474     uint32_t ssi_uid;     /* Real UID of sender */
 475     int32_t  ssi_fd;      /* File descriptor (SIGIO) */
 476     uint32_t ssi_tid;     /* Kernel timer ID (POSIX timers) */
 477     uint32_t ssi_band;    /* Band event (SIGIO) */
 478     uint32_t ssi_overrun; /* POSIX timer overrun count */
 479     uint32_t ssi_trapno;  /* Trap number that caused signal */
 480     int32_t  ssi_status;  /* Exit status or signal (SIGCHLD) */
 481     int32_t  ssi_int;     /* Integer sent by sigqueue(2) */
 482     uint64_t ssi_ptr;     /* Pointer sent by sigqueue(2) */
 483     uint64_t ssi_utime;   /* User CPU time consumed (SIGCHLD) */
 484     uint64_t ssi_stime;   /* System CPU time consumed (SIGCHLD) */
 485     uint64_t ssi_addr;    /* Address that generated signal
 486                              (for hardware-generated signals) */
 487     uint8_t  pad[48];     /* Pad size to 128 bytes (allow for
 488                              additional fields in the future) */
 489 };
 490
 491 int qemu_signalfd(const sigset_t *mask);
 492 void sigaction_invoke(struct sigaction *action,
 493                       struct qemu_signalfd_siginfo *info);
 494 #endif
 495
 496 int qemu_madvise(void *addr, size_t len, int advice);
 497 int qemu_mprotect_rwx(void *addr, size_t size);
 498 int qemu_mprotect_none(void *addr, size_t size);
 499
 500 /*
 501  * Don't introduce new usage of this function, prefer the following
 502  * qemu_open/qemu_create that take an "Error **errp"
 503  */
 504 int qemu_open_old(const char *name, int flags, ...);
 505 int qemu_open(const char *name, int flags, Error **errp);
 506 int qemu_create(const char *name, int flags, mode_t mode, Error **errp);
 507 int qemu_close(int fd);
 508 int qemu_unlink(const char *name);
 509 #ifndef _WIN32
 510 int qemu_dup_flags(int fd, int flags);
 511 int qemu_dup(int fd);
 512 int qemu_lock_fd(int fd, int64_t start, int64_t len, bool exclusive);
 513 int qemu_unlock_fd(int fd, int64_t start, int64_t len);
 514 int qemu_lock_fd_test(int fd, int64_t start, int64_t len, bool exclusive);
 515 bool qemu_has_ofd_lock(void);
 516 #endif
 517
 518 #if defined(__HAIKU__) && defined(__i386__)
 519 #define FMT_pid "%ld"
 520 #elif defined(WIN64)
 521 #define FMT_pid "%" PRId64
 522 #else
 523 #define FMT_pid "%d"
 524 #endif
 525
 526 bool qemu_write_pidfile(const char *pidfile, Error **errp);
 527
 528 int qemu_get_thread_id(void);
 529
 530 #ifndef CONFIG_IOVEC
 531 struct iovec {
 532     void *iov_base;
 533     size_t iov_len;
 534 };
 535 /*
 536  * Use the same value as Linux for now.
 537  */
 538 #define IOV_MAX 1024
 539
 540 ssize_t readv(int fd, const struct iovec *iov, int iov_cnt);
 541 ssize_t writev(int fd, const struct iovec *iov, int iov_cnt);
 542 #else
 543 #include <sys/uio.h>
 544 #endif
 545
 546 #ifdef _WIN32
 547 static inline void qemu_timersub(const struct timeval *val1,
 548                                  const struct timeval *val2,
 549                                  struct timeval *res)
 550 {
 551     res->tv_sec = val1->tv_sec - val2->tv_sec;
 552     if (val1->tv_usec < val2->tv_usec) {
 553         res->tv_sec--;
 554         res->tv_usec = val1->tv_usec - val2->tv_usec + 1000 * 1000;
 555     } else {
 556         res->tv_usec = val1->tv_usec - val2->tv_usec;
 557     }
 558 }
 559 #else
 560 #define qemu_timersub timersub
 561 #endif
 562
 563 void qemu_set_cloexec(int fd);
 564
 565 /* Starting on QEMU 2.5, qemu_hw_version() returns "2.5+" by default
 566  * instead of QEMU_VERSION, so setting hw_version on MachineClass
 567  * is no longer mandatory.
 568  *
 569  * Do NOT change this string, or it will break compatibility on all
 570  * machine classes that don't set hw_version.
 571  */
 572 #define QEMU_HW_VERSION "2.5+"
 573
 574 /* QEMU "hardware version" setting. Used to replace code that exposed
 575  * QEMU_VERSION to guests in the past and need to keep compatibility.
 576  * Do not use qemu_hw_version() in new code.
 577  */
 578 void qemu_set_hw_version(const char *);
 579 const char *qemu_hw_version(void);
 580
 581 void fips_set_state(bool requested);
 582 bool fips_get_state(void);
 583
 584 /* Return a dynamically allocated pathname denoting a file or directory that is
 585  * appropriate for storing local state.
 586  *
 587  * @relative_pathname need not start with a directory separator; one will be
 588  * added automatically.
 589  *
 590  * The caller is responsible for releasing the value returned with g_free()
 591  * after use.
 592  */
 593 char *qemu_get_local_state_pathname(const char *relative_pathname);
 594
 595 /* Find program directory, and save it for later usage with
 596  * qemu_get_exec_dir().
 597  * Try OS specific API first, if not working, parse from argv0. */
 598 void qemu_init_exec_dir(const char *argv0);
 599
 600 /* Get the saved exec dir.  */
 601 const char *qemu_get_exec_dir(void);
 602
 603 /**
 604  * qemu_getauxval:
 605  * @type: the auxiliary vector key to lookup
 606  *
 607  * Search the auxiliary vector for @type, returning the value
 608  * or 0 if @type is not present.
 609  */
 610 unsigned long qemu_getauxval(unsigned long type);
 611
 612 void qemu_set_tty_echo(int fd, bool echo);
 613
 614 void os_mem_prealloc(int fd, char *area, size_t sz, int smp_cpus,
 615                      Error **errp);
 616
 617 /**
 618  * qemu_get_pid_name:
 619  * @pid: pid of a process
 620  *
 621  * For given @pid fetch its name. Caller is responsible for
 622  * freeing the string when no longer needed.
 623  * Returns allocated string on success, NULL on failure.
 624  */
 625 char *qemu_get_pid_name(pid_t pid);
 626
 627 /**
 628  * qemu_fork:
 629  *
 630  * A version of fork that avoids signal handler race
 631  * conditions that can lead to child process getting
 632  * signals that are otherwise only expected by the
 633  * parent. It also resets all signal handlers to the
 634  * default settings.
 635  *
 636  * Returns 0 to child process, pid number to parent
 637  * or -1 on failure.
 638  */
 639 pid_t qemu_fork(Error **errp);
 640
 641 /* Using intptr_t ensures that qemu_*_page_mask is sign-extended even
 642  * when intptr_t is 32-bit and we are aligning a long long.
 643  */
 644 extern uintptr_t qemu_real_host_page_size;
 645 extern intptr_t qemu_real_host_page_mask;
 646
 647 extern int qemu_icache_linesize;
 648 extern int qemu_icache_linesize_log;
 649 extern int qemu_dcache_linesize;
 650 extern int qemu_dcache_linesize_log;
 651
 652 /*
 653  * After using getopt or getopt_long, if you need to parse another set
 654  * of options, then you must reset optind.  Unfortunately the way to
 655  * do this varies between implementations of getopt.
 656  */
 657 static inline void qemu_reset_optind(void)
 658 {
 659 #ifdef HAVE_OPTRESET
 660     optind = 1;
 661     optreset = 1;
 662 #else
 663     optind = 0;
 664 #endif
 665 }
 666
 667 /**
 668  * qemu_get_host_name:
 669  * @errp: Error object
 670  *
 671  * Operating system agnostic way of querying host name.
 672  *
 673  * Returns allocated hostname (caller should free), NULL on failure.
 674  */
 675 char *qemu_get_host_name(Error **errp);
 676
 677 /**
 678  * qemu_get_host_physmem:
 679  *
 680  * Operating system agnostic way of querying host memory.
 681  *
 682  * Returns amount of physical memory on the system. This is purely
 683  * advisery and may return 0 if we can't work it out. At the other
 684  * end we saturate to SIZE_MAX if you are lucky enough to have that
 685  * much memory.
 686  */
 687 size_t qemu_get_host_physmem(void);
 688
 689 /*
 690  * Toggle write/execute on the pages marked MAP_JIT
 691  * for the current thread.
 692  */
 693 #if defined(MAC_OS_VERSION_11_0) && \
 694     MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_VERSION_11_0
 695 static inline void qemu_thread_jit_execute(void)
 696 {
 697     if (__builtin_available(macOS 11.0, *)) {
 698         pthread_jit_write_protect_np(true);
 699     }
 700 }
 701
 702 static inline void qemu_thread_jit_write(void)
 703 {
 704     if (__builtin_available(macOS 11.0, *)) {
 705         pthread_jit_write_protect_np(false);
 706     }
 707 }
 708 #else
 709 static inline void qemu_thread_jit_write(void) {}
 710 static inline void qemu_thread_jit_execute(void) {}
 711 #endif
 712
 713 /**
 714  * Platforms which do not support system() return ENOSYS
 715  */
 716 #ifndef HAVE_SYSTEM_FUNCTION
 717 #define system platform_does_not_support_system
 718 static inline int platform_does_not_support_system(const char *command)
 719 {
 720     errno = ENOSYS;
 721     return -1;
 722 }
 723 #endif /* !HAVE_SYSTEM_FUNCTION */
 724
 725 #endif