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 /*
 115  * This is somewhat like a system header; it must be outside any extern "C"
 116  * block because it includes system headers itself, including glib.h,
 117  * which will not compile if inside an extern "C" block.
 118  */
 119 #include "glib-compat.h"
 120
 121 #ifdef _WIN32
 122 #include "sysemu/os-win32.h"
 123 #endif
 124
 125 #ifdef CONFIG_POSIX
 126 #include "sysemu/os-posix.h"
 127 #endif
 128
 129 #ifdef __APPLE__
 130 #include <AvailabilityMacros.h>
 131 #endif
 132
 133 #include "qemu/typedefs.h"
 134
 135 /*
 136  * For mingw, as of v6.0.0, the function implementing the assert macro is
 137  * not marked as noreturn, so the compiler cannot delete code following an
 138  * assert(false) as unused.  We rely on this within the code base to delete
 139  * code that is unreachable when features are disabled.
 140  * All supported versions of Glib's g_assert() satisfy this requirement.
 141  */
 142 #ifdef __MINGW32__
 143 #undef assert
 144 #define assert(x)  g_assert(x)
 145 #endif
 146
 147 /*
 148  * According to waitpid man page:
 149  * WCOREDUMP
 150  *  This  macro  is  not  specified  in POSIX.1-2001 and is not
 151  *  available on some UNIX implementations (e.g., AIX, SunOS).
 152  *  Therefore, enclose its use inside #ifdef WCOREDUMP ... #endif.
 153  */
 154 #ifndef WCOREDUMP
 155 #define WCOREDUMP(status) 0
 156 #endif
 157 /*
 158  * We have a lot of unaudited code that may fail in strange ways, or
 159  * even be a security risk during migration, if you disable assertions
 160  * at compile-time.  You may comment out these safety checks if you
 161  * absolutely want to disable assertion overhead, but it is not
 162  * supported upstream so the risk is all yours.  Meanwhile, please
 163  * submit patches to remove any side-effects inside an assertion, or
 164  * fixing error handling that should use Error instead of assert.
 165  */
 166 #ifdef NDEBUG
 167 #error building with NDEBUG is not supported
 168 #endif
 169 #ifdef G_DISABLE_ASSERT
 170 #error building with G_DISABLE_ASSERT is not supported
 171 #endif
 172
 173 #ifndef O_LARGEFILE
 174 #define O_LARGEFILE 0
 175 #endif
 176 #ifndef O_BINARY
 177 #define O_BINARY 0
 178 #endif
 179 #ifndef MAP_ANONYMOUS
 180 #define MAP_ANONYMOUS MAP_ANON
 181 #endif
 182 #ifndef MAP_FIXED_NOREPLACE
 183 #define MAP_FIXED_NOREPLACE 0
 184 #endif
 185 #ifndef ENOMEDIUM
 186 #define ENOMEDIUM ENODEV
 187 #endif
 188 #if !defined(ENOTSUP)
 189 #define ENOTSUP 4096
 190 #endif
 191 #if !defined(ECANCELED)
 192 #define ECANCELED 4097
 193 #endif
 194 #if !defined(EMEDIUMTYPE)
 195 #define EMEDIUMTYPE 4098
 196 #endif
 197 #if !defined(ESHUTDOWN)
 198 #define ESHUTDOWN 4099
 199 #endif
 200
 201 /* time_t may be either 32 or 64 bits depending on the host OS, and
 202  * can be either signed or unsigned, so we can't just hardcode a
 203  * specific maximum value. This is not a C preprocessor constant,
 204  * so you can't use TIME_MAX in an #ifdef, but for our purposes
 205  * this isn't a problem.
 206  */
 207
 208 /* The macros TYPE_SIGNED, TYPE_WIDTH, and TYPE_MAXIMUM are from
 209  * Gnulib, and are under the LGPL v2.1 or (at your option) any
 210  * later version.
 211  */
 212
 213 /* True if the real type T is signed.  */
 214 #define TYPE_SIGNED(t) (!((t)0 < (t)-1))
 215
 216 /* The width in bits of the integer type or expression T.
 217  * Padding bits are not supported.
 218  */
 219 #define TYPE_WIDTH(t) (sizeof(t) * CHAR_BIT)
 220
 221 /* The maximum and minimum values for the integer type T.  */
 222 #define TYPE_MAXIMUM(t)                                                \
 223   ((t) (!TYPE_SIGNED(t)                                                \
 224         ? (t)-1                                                        \
 225         : ((((t)1 << (TYPE_WIDTH(t) - 2)) - 1) * 2 + 1)))
 226
 227 #ifndef TIME_MAX
 228 #define TIME_MAX TYPE_MAXIMUM(time_t)
 229 #endif
 230
 231 /* HOST_LONG_BITS is the size of a native pointer in bits. */
 232 #if UINTPTR_MAX == UINT32_MAX
 233 # define HOST_LONG_BITS 32
 234 #elif UINTPTR_MAX == UINT64_MAX
 235 # define HOST_LONG_BITS 64
 236 #else
 237 # error Unknown pointer size
 238 #endif
 239
 240 /* Mac OSX has a <stdint.h> bug that incorrectly defines SIZE_MAX with
 241  * the wrong type. Our replacement isn't usable in preprocessor
 242  * expressions, but it is sufficient for our needs. */
 243 #if defined(HAVE_BROKEN_SIZE_MAX) && HAVE_BROKEN_SIZE_MAX
 244 #undef SIZE_MAX
 245 #define SIZE_MAX ((size_t)-1)
 246 #endif
 247
 248 /*
 249  * Two variations of MIN/MAX macros. The first is for runtime use, and
 250  * evaluates arguments only once (so it is safe even with side
 251  * effects), but will not work in constant contexts (such as array
 252  * size declarations) because of the '{}'.  The second is for constant
 253  * expression use, where evaluating arguments twice is safe because
 254  * the result is going to be constant anyway, but will not work in a
 255  * runtime context because of a void expression where a value is
 256  * expected.  Thus, both gcc and clang will fail to compile if you use
 257  * the wrong macro (even if the error may seem a bit cryptic).
 258  *
 259  * Note that neither form is usable as an #if condition; if you truly
 260  * need to write conditional code that depends on a minimum or maximum
 261  * determined by the pre-processor instead of the compiler, you'll
 262  * have to open-code it.  Sadly, Coverity is severely confused by the
 263  * constant variants, so we have to dumb things down there.
 264  */
 265 #undef MIN
 266 #define MIN(a, b)                                       \
 267     ({                                                  \
 268         typeof(1 ? (a) : (b)) _a = (a), _b = (b);       \
 269         _a < _b ? _a : _b;                              \
 270     })
 271 #undef MAX
 272 #define MAX(a, b)                                       \
 273     ({                                                  \
 274         typeof(1 ? (a) : (b)) _a = (a), _b = (b);       \
 275         _a > _b ? _a : _b;                              \
 276     })
 277
 278 #ifdef __COVERITY__
 279 # define MIN_CONST(a, b) ((a) < (b) ? (a) : (b))
 280 # define MAX_CONST(a, b) ((a) > (b) ? (a) : (b))
 281 #else
 282 # define MIN_CONST(a, b)                                        \
 283     __builtin_choose_expr(                                      \
 284         __builtin_constant_p(a) && __builtin_constant_p(b),     \
 285         (a) < (b) ? (a) : (b),                                  \
 286         ((void)0))
 287 # define MAX_CONST(a, b)                                        \
 288     __builtin_choose_expr(                                      \
 289         __builtin_constant_p(a) && __builtin_constant_p(b),     \
 290         (a) > (b) ? (a) : (b),                                  \
 291         ((void)0))
 292 #endif
 293
 294 /*
 295  * Minimum function that returns zero only if both values are zero.
 296  * Intended for use with unsigned values only.
 297  */
 298 #ifndef MIN_NON_ZERO
 299 #define MIN_NON_ZERO(a, b)                              \
 300     ({                                                  \
 301         typeof(1 ? (a) : (b)) _a = (a), _b = (b);       \
 302         _a == 0 ? _b : (_b == 0 || _b > _a) ? _a : _b;  \
 303     })
 304 #endif
 305
 306 /* Round number down to multiple */
 307 #define QEMU_ALIGN_DOWN(n, m) ((n) / (m) * (m))
 308
 309 /* Round number up to multiple. Safe when m is not a power of 2 (see
 310  * ROUND_UP for a faster version when a power of 2 is guaranteed) */
 311 #define QEMU_ALIGN_UP(n, m) QEMU_ALIGN_DOWN((n) + (m) - 1, (m))
 312
 313 /* Check if n is a multiple of m */
 314 #define QEMU_IS_ALIGNED(n, m) (((n) % (m)) == 0)
 315
 316 /* n-byte align pointer down */
 317 #define QEMU_ALIGN_PTR_DOWN(p, n) \
 318     ((typeof(p))QEMU_ALIGN_DOWN((uintptr_t)(p), (n)))
 319
 320 /* n-byte align pointer up */
 321 #define QEMU_ALIGN_PTR_UP(p, n) \
 322     ((typeof(p))QEMU_ALIGN_UP((uintptr_t)(p), (n)))
 323
 324 /* Check if pointer p is n-bytes aligned */
 325 #define QEMU_PTR_IS_ALIGNED(p, n) QEMU_IS_ALIGNED((uintptr_t)(p), (n))
 326
 327 /* Round number up to multiple. Requires that d be a power of 2 (see
 328  * QEMU_ALIGN_UP for a safer but slower version on arbitrary
 329  * numbers); works even if d is a smaller type than n.  */
 330 #ifndef ROUND_UP
 331 #define ROUND_UP(n, d) (((n) + (d) - 1) & -(0 ? (n) : (d)))
 332 #endif
 333
 334 #ifndef DIV_ROUND_UP
 335 #define DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d))
 336 #endif
 337
 338 /*
 339  * &(x)[0] is always a pointer - if it's same type as x then the argument is a
 340  * pointer, not an array.
 341  */
 342 #define QEMU_IS_ARRAY(x) (!__builtin_types_compatible_p(typeof(x), \
 343                                                         typeof(&(x)[0])))
 344 #ifndef ARRAY_SIZE
 345 #define ARRAY_SIZE(x) ((sizeof(x) / sizeof((x)[0])) + \
 346                        QEMU_BUILD_BUG_ON_ZERO(!QEMU_IS_ARRAY(x)))
 347 #endif
 348
 349 int qemu_daemon(int nochdir, int noclose);
 350 void *qemu_try_memalign(size_t alignment, size_t size);
 351 void *qemu_memalign(size_t alignment, size_t size);
 352 void *qemu_anon_ram_alloc(size_t size, uint64_t *align, bool shared);
 353 void qemu_vfree(void *ptr);
 354 void qemu_anon_ram_free(void *ptr, size_t size);
 355
 356 #define QEMU_MADV_INVALID -1
 357
 358 #if defined(CONFIG_MADVISE)
 359
 360 #define QEMU_MADV_WILLNEED  MADV_WILLNEED
 361 #define QEMU_MADV_DONTNEED  MADV_DONTNEED
 362 #ifdef MADV_DONTFORK
 363 #define QEMU_MADV_DONTFORK  MADV_DONTFORK
 364 #else
 365 #define QEMU_MADV_DONTFORK  QEMU_MADV_INVALID
 366 #endif
 367 #ifdef MADV_MERGEABLE
 368 #define QEMU_MADV_MERGEABLE MADV_MERGEABLE
 369 #else
 370 #define QEMU_MADV_MERGEABLE QEMU_MADV_INVALID
 371 #endif
 372 #ifdef MADV_UNMERGEABLE
 373 #define QEMU_MADV_UNMERGEABLE MADV_UNMERGEABLE
 374 #else
 375 #define QEMU_MADV_UNMERGEABLE QEMU_MADV_INVALID
 376 #endif
 377 #ifdef MADV_DODUMP
 378 #define QEMU_MADV_DODUMP MADV_DODUMP
 379 #else
 380 #define QEMU_MADV_DODUMP QEMU_MADV_INVALID
 381 #endif
 382 #ifdef MADV_DONTDUMP
 383 #define QEMU_MADV_DONTDUMP MADV_DONTDUMP
 384 #else
 385 #define QEMU_MADV_DONTDUMP QEMU_MADV_INVALID
 386 #endif
 387 #ifdef MADV_HUGEPAGE
 388 #define QEMU_MADV_HUGEPAGE MADV_HUGEPAGE
 389 #else
 390 #define QEMU_MADV_HUGEPAGE QEMU_MADV_INVALID
 391 #endif
 392 #ifdef MADV_NOHUGEPAGE
 393 #define QEMU_MADV_NOHUGEPAGE MADV_NOHUGEPAGE
 394 #else
 395 #define QEMU_MADV_NOHUGEPAGE QEMU_MADV_INVALID
 396 #endif
 397 #ifdef MADV_REMOVE
 398 #define QEMU_MADV_REMOVE MADV_REMOVE
 399 #else
 400 #define QEMU_MADV_REMOVE QEMU_MADV_INVALID
 401 #endif
 402
 403 #elif defined(CONFIG_POSIX_MADVISE)
 404
 405 #define QEMU_MADV_WILLNEED  POSIX_MADV_WILLNEED
 406 #define QEMU_MADV_DONTNEED  POSIX_MADV_DONTNEED
 407 #define QEMU_MADV_DONTFORK  QEMU_MADV_INVALID
 408 #define QEMU_MADV_MERGEABLE QEMU_MADV_INVALID
 409 #define QEMU_MADV_UNMERGEABLE QEMU_MADV_INVALID
 410 #define QEMU_MADV_DODUMP QEMU_MADV_INVALID
 411 #define QEMU_MADV_DONTDUMP QEMU_MADV_INVALID
 412 #define QEMU_MADV_HUGEPAGE  QEMU_MADV_INVALID
 413 #define QEMU_MADV_NOHUGEPAGE  QEMU_MADV_INVALID
 414 #define QEMU_MADV_REMOVE QEMU_MADV_INVALID
 415
 416 #else /* no-op */
 417
 418 #define QEMU_MADV_WILLNEED  QEMU_MADV_INVALID
 419 #define QEMU_MADV_DONTNEED  QEMU_MADV_INVALID
 420 #define QEMU_MADV_DONTFORK  QEMU_MADV_INVALID
 421 #define QEMU_MADV_MERGEABLE QEMU_MADV_INVALID
 422 #define QEMU_MADV_UNMERGEABLE QEMU_MADV_INVALID
 423 #define QEMU_MADV_DODUMP QEMU_MADV_INVALID
 424 #define QEMU_MADV_DONTDUMP QEMU_MADV_INVALID
 425 #define QEMU_MADV_HUGEPAGE  QEMU_MADV_INVALID
 426 #define QEMU_MADV_NOHUGEPAGE  QEMU_MADV_INVALID
 427 #define QEMU_MADV_REMOVE QEMU_MADV_INVALID
 428
 429 #endif
 430
 431 #ifdef _WIN32
 432 #define HAVE_CHARDEV_SERIAL 1
 433 #elif defined(__linux__) || defined(__sun__) || defined(__FreeBSD__)    \
 434     || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) \
 435     || defined(__GLIBC__) || defined(__APPLE__)
 436 #define HAVE_CHARDEV_SERIAL 1
 437 #endif
 438
 439 #if defined(__linux__) || defined(__FreeBSD__) ||               \
 440     defined(__FreeBSD_kernel__) || defined(__DragonFly__)
 441 #define HAVE_CHARDEV_PARPORT 1
 442 #endif
 443
 444 #if defined(__HAIKU__)
 445 #define SIGIO SIGPOLL
 446 #endif
 447
 448 #if defined(CONFIG_LINUX)
 449 #ifndef BUS_MCEERR_AR
 450 #define BUS_MCEERR_AR 4
 451 #endif
 452 #ifndef BUS_MCEERR_AO
 453 #define BUS_MCEERR_AO 5
 454 #endif
 455 #endif
 456
 457 #if defined(__linux__) && \
 458     (defined(__x86_64__) || defined(__arm__) || defined(__aarch64__) \
 459      || defined(__powerpc64__))
 460    /* Use 2 MiB alignment so transparent hugepages can be used by KVM.
 461       Valgrind does not support alignments larger than 1 MiB,
 462       therefore we need special code which handles running on Valgrind. */
 463 #  define QEMU_VMALLOC_ALIGN (512 * 4096)
 464 #elif defined(__linux__) && defined(__s390x__)
 465    /* Use 1 MiB (segment size) alignment so gmap can be used by KVM. */
 466 #  define QEMU_VMALLOC_ALIGN (256 * 4096)
 467 #elif defined(__linux__) && defined(__sparc__)
 468 #include <sys/shm.h>
 469 #  define QEMU_VMALLOC_ALIGN MAX(qemu_real_host_page_size, SHMLBA)
 470 #else
 471 #  define QEMU_VMALLOC_ALIGN qemu_real_host_page_size
 472 #endif
 473
 474 #ifdef CONFIG_POSIX
 475 struct qemu_signalfd_siginfo {
 476     uint32_t ssi_signo;   /* Signal number */
 477     int32_t  ssi_errno;   /* Error number (unused) */
 478     int32_t  ssi_code;    /* Signal code */
 479     uint32_t ssi_pid;     /* PID of sender */
 480     uint32_t ssi_uid;     /* Real UID of sender */
 481     int32_t  ssi_fd;      /* File descriptor (SIGIO) */
 482     uint32_t ssi_tid;     /* Kernel timer ID (POSIX timers) */
 483     uint32_t ssi_band;    /* Band event (SIGIO) */
 484     uint32_t ssi_overrun; /* POSIX timer overrun count */
 485     uint32_t ssi_trapno;  /* Trap number that caused signal */
 486     int32_t  ssi_status;  /* Exit status or signal (SIGCHLD) */
 487     int32_t  ssi_int;     /* Integer sent by sigqueue(2) */
 488     uint64_t ssi_ptr;     /* Pointer sent by sigqueue(2) */
 489     uint64_t ssi_utime;   /* User CPU time consumed (SIGCHLD) */
 490     uint64_t ssi_stime;   /* System CPU time consumed (SIGCHLD) */
 491     uint64_t ssi_addr;    /* Address that generated signal
 492                              (for hardware-generated signals) */
 493     uint8_t  pad[48];     /* Pad size to 128 bytes (allow for
 494                              additional fields in the future) */
 495 };
 496
 497 int qemu_signalfd(const sigset_t *mask);
 498 void sigaction_invoke(struct sigaction *action,
 499                       struct qemu_signalfd_siginfo *info);
 500 #endif
 501
 502 int qemu_madvise(void *addr, size_t len, int advice);
 503 int qemu_mprotect_rwx(void *addr, size_t size);
 504 int qemu_mprotect_none(void *addr, size_t size);
 505
 506 /*
 507  * Don't introduce new usage of this function, prefer the following
 508  * qemu_open/qemu_create that take an "Error **errp"
 509  */
 510 int qemu_open_old(const char *name, int flags, ...);
 511 int qemu_open(const char *name, int flags, Error **errp);
 512 int qemu_create(const char *name, int flags, mode_t mode, Error **errp);
 513 int qemu_close(int fd);
 514 int qemu_unlink(const char *name);
 515 #ifndef _WIN32
 516 int qemu_dup_flags(int fd, int flags);
 517 int qemu_dup(int fd);
 518 int qemu_lock_fd(int fd, int64_t start, int64_t len, bool exclusive);
 519 int qemu_unlock_fd(int fd, int64_t start, int64_t len);
 520 int qemu_lock_fd_test(int fd, int64_t start, int64_t len, bool exclusive);
 521 bool qemu_has_ofd_lock(void);
 522 #endif
 523
 524 #if defined(__HAIKU__) && defined(__i386__)
 525 #define FMT_pid "%ld"
 526 #elif defined(WIN64)
 527 #define FMT_pid "%" PRId64
 528 #else
 529 #define FMT_pid "%d"
 530 #endif
 531
 532 bool qemu_write_pidfile(const char *pidfile, Error **errp);
 533
 534 int qemu_get_thread_id(void);
 535
 536 #ifndef CONFIG_IOVEC
 537 struct iovec {
 538     void *iov_base;
 539     size_t iov_len;
 540 };
 541 /*
 542  * Use the same value as Linux for now.
 543  */
 544 #define IOV_MAX 1024
 545
 546 ssize_t readv(int fd, const struct iovec *iov, int iov_cnt);
 547 ssize_t writev(int fd, const struct iovec *iov, int iov_cnt);
 548 #else
 549 #include <sys/uio.h>
 550 #endif
 551
 552 #ifdef _WIN32
 553 static inline void qemu_timersub(const struct timeval *val1,
 554                                  const struct timeval *val2,
 555                                  struct timeval *res)
 556 {
 557     res->tv_sec = val1->tv_sec - val2->tv_sec;
 558     if (val1->tv_usec < val2->tv_usec) {
 559         res->tv_sec--;
 560         res->tv_usec = val1->tv_usec - val2->tv_usec + 1000 * 1000;
 561     } else {
 562         res->tv_usec = val1->tv_usec - val2->tv_usec;
 563     }
 564 }
 565 #else
 566 #define qemu_timersub timersub
 567 #endif
 568
 569 void qemu_set_cloexec(int fd);
 570
 571 /* Starting on QEMU 2.5, qemu_hw_version() returns "2.5+" by default
 572  * instead of QEMU_VERSION, so setting hw_version on MachineClass
 573  * is no longer mandatory.
 574  *
 575  * Do NOT change this string, or it will break compatibility on all
 576  * machine classes that don't set hw_version.
 577  */
 578 #define QEMU_HW_VERSION "2.5+"
 579
 580 /* QEMU "hardware version" setting. Used to replace code that exposed
 581  * QEMU_VERSION to guests in the past and need to keep compatibility.
 582  * Do not use qemu_hw_version() in new code.
 583  */
 584 void qemu_set_hw_version(const char *);
 585 const char *qemu_hw_version(void);
 586
 587 void fips_set_state(bool requested);
 588 bool fips_get_state(void);
 589
 590 /* Return a dynamically allocated pathname denoting a file or directory that is
 591  * appropriate for storing local state.
 592  *
 593  * @relative_pathname need not start with a directory separator; one will be
 594  * added automatically.
 595  *
 596  * The caller is responsible for releasing the value returned with g_free()
 597  * after use.
 598  */
 599 char *qemu_get_local_state_pathname(const char *relative_pathname);
 600
 601 /* Find program directory, and save it for later usage with
 602  * qemu_get_exec_dir().
 603  * Try OS specific API first, if not working, parse from argv0. */
 604 void qemu_init_exec_dir(const char *argv0);
 605
 606 /* Get the saved exec dir.  */
 607 const char *qemu_get_exec_dir(void);
 608
 609 /**
 610  * qemu_getauxval:
 611  * @type: the auxiliary vector key to lookup
 612  *
 613  * Search the auxiliary vector for @type, returning the value
 614  * or 0 if @type is not present.
 615  */
 616 unsigned long qemu_getauxval(unsigned long type);
 617
 618 void qemu_set_tty_echo(int fd, bool echo);
 619
 620 void os_mem_prealloc(int fd, char *area, size_t sz, int smp_cpus,
 621                      Error **errp);
 622
 623 /**
 624  * qemu_get_pid_name:
 625  * @pid: pid of a process
 626  *
 627  * For given @pid fetch its name. Caller is responsible for
 628  * freeing the string when no longer needed.
 629  * Returns allocated string on success, NULL on failure.
 630  */
 631 char *qemu_get_pid_name(pid_t pid);
 632
 633 /**
 634  * qemu_fork:
 635  *
 636  * A version of fork that avoids signal handler race
 637  * conditions that can lead to child process getting
 638  * signals that are otherwise only expected by the
 639  * parent. It also resets all signal handlers to the
 640  * default settings.
 641  *
 642  * Returns 0 to child process, pid number to parent
 643  * or -1 on failure.
 644  */
 645 pid_t qemu_fork(Error **errp);
 646
 647 /* Using intptr_t ensures that qemu_*_page_mask is sign-extended even
 648  * when intptr_t is 32-bit and we are aligning a long long.
 649  */
 650 extern uintptr_t qemu_real_host_page_size;
 651 extern intptr_t qemu_real_host_page_mask;
 652
 653 extern int qemu_icache_linesize;
 654 extern int qemu_icache_linesize_log;
 655 extern int qemu_dcache_linesize;
 656 extern int qemu_dcache_linesize_log;
 657
 658 /*
 659  * After using getopt or getopt_long, if you need to parse another set
 660  * of options, then you must reset optind.  Unfortunately the way to
 661  * do this varies between implementations of getopt.
 662  */
 663 static inline void qemu_reset_optind(void)
 664 {
 665 #ifdef HAVE_OPTRESET
 666     optind = 1;
 667     optreset = 1;
 668 #else
 669     optind = 0;
 670 #endif
 671 }
 672
 673 /**
 674  * qemu_get_host_name:
 675  * @errp: Error object
 676  *
 677  * Operating system agnostic way of querying host name.
 678  *
 679  * Returns allocated hostname (caller should free), NULL on failure.
 680  */
 681 char *qemu_get_host_name(Error **errp);
 682
 683 /**
 684  * qemu_get_host_physmem:
 685  *
 686  * Operating system agnostic way of querying host memory.
 687  *
 688  * Returns amount of physical memory on the system. This is purely
 689  * advisery and may return 0 if we can't work it out. At the other
 690  * end we saturate to SIZE_MAX if you are lucky enough to have that
 691  * much memory.
 692  */
 693 size_t qemu_get_host_physmem(void);
 694
 695 /*
 696  * Toggle write/execute on the pages marked MAP_JIT
 697  * for the current thread.
 698  */
 699 #if defined(MAC_OS_VERSION_11_0) && \
 700     MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_VERSION_11_0
 701 static inline void qemu_thread_jit_execute(void)
 702 {
 703     if (__builtin_available(macOS 11.0, *)) {
 704         pthread_jit_write_protect_np(true);
 705     }
 706 }
 707
 708 static inline void qemu_thread_jit_write(void)
 709 {
 710     if (__builtin_available(macOS 11.0, *)) {
 711         pthread_jit_write_protect_np(false);
 712     }
 713 }
 714 #else
 715 static inline void qemu_thread_jit_write(void) {}
 716 static inline void qemu_thread_jit_execute(void) {}
 717 #endif
 718
 719 /**
 720  * Platforms which do not support system() return ENOSYS
 721  */
 722 #ifndef HAVE_SYSTEM_FUNCTION
 723 #define system platform_does_not_support_system
 724 static inline int platform_does_not_support_system(const char *command)
 725 {
 726     errno = ENOSYS;
 727     return -1;
 728 }
 729 #endif /* !HAVE_SYSTEM_FUNCTION */
 730
 731 #endif