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 QEMU_EXTERN_C 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 #ifdef CONFIG_IOVEC 108 #include <sys/uio.h> 109 #endif 110 111 #if defined(__linux__) && defined(__sparc__) 112 /* The SPARC definition of QEMU_VMALLOC_ALIGN needs SHMLBA */ 113 #include <sys/shm.h> 114 #endif 115 116 #ifndef _WIN32 117 #include <sys/wait.h> 118 #else 119 #define WIFEXITED(x) 1 120 #define WEXITSTATUS(x) (x) 121 #endif 122 123 #ifdef __APPLE__ 124 #include <AvailabilityMacros.h> 125 #endif 126 127 /* 128 * This is somewhat like a system header; it must be outside any extern "C" 129 * block because it includes system headers itself, including glib.h, 130 * which will not compile if inside an extern "C" block. 131 */ 132 #include "glib-compat.h" 133 134 #ifdef _WIN32 135 #include "sysemu/os-win32.h" 136 #endif 137 138 #ifdef CONFIG_POSIX 139 #include "sysemu/os-posix.h" 140 #endif 141 142 #ifdef __cplusplus 143 extern "C" { 144 #endif 145 146 #include "qemu/typedefs.h" 147 148 /* 149 * For mingw, as of v6.0.0, the function implementing the assert macro is 150 * not marked as noreturn, so the compiler cannot delete code following an 151 * assert(false) as unused. We rely on this within the code base to delete 152 * code that is unreachable when features are disabled. 153 * All supported versions of Glib's g_assert() satisfy this requirement. 154 */ 155 #ifdef __MINGW32__ 156 #undef assert 157 #define assert(x) g_assert(x) 158 #endif 159 160 /* 161 * According to waitpid man page: 162 * WCOREDUMP 163 * This macro is not specified in POSIX.1-2001 and is not 164 * available on some UNIX implementations (e.g., AIX, SunOS). 165 * Therefore, enclose its use inside #ifdef WCOREDUMP ... #endif. 166 */ 167 #ifndef WCOREDUMP 168 #define WCOREDUMP(status) 0 169 #endif 170 /* 171 * We have a lot of unaudited code that may fail in strange ways, or 172 * even be a security risk during migration, if you disable assertions 173 * at compile-time. You may comment out these safety checks if you 174 * absolutely want to disable assertion overhead, but it is not 175 * supported upstream so the risk is all yours. Meanwhile, please 176 * submit patches to remove any side-effects inside an assertion, or 177 * fixing error handling that should use Error instead of assert. 178 */ 179 #ifdef NDEBUG 180 #error building with NDEBUG is not supported 181 #endif 182 #ifdef G_DISABLE_ASSERT 183 #error building with G_DISABLE_ASSERT is not supported 184 #endif 185 186 #ifndef O_LARGEFILE 187 #define O_LARGEFILE 0 188 #endif 189 #ifndef O_BINARY 190 #define O_BINARY 0 191 #endif 192 #ifndef MAP_ANONYMOUS 193 #define MAP_ANONYMOUS MAP_ANON 194 #endif 195 #ifndef MAP_FIXED_NOREPLACE 196 #define MAP_FIXED_NOREPLACE 0 197 #endif 198 #ifndef MAP_NORESERVE 199 #define MAP_NORESERVE 0 200 #endif 201 #ifndef ENOMEDIUM 202 #define ENOMEDIUM ENODEV 203 #endif 204 #if !defined(ENOTSUP) 205 #define ENOTSUP 4096 206 #endif 207 #if !defined(ECANCELED) 208 #define ECANCELED 4097 209 #endif 210 #if !defined(EMEDIUMTYPE) 211 #define EMEDIUMTYPE 4098 212 #endif 213 #if !defined(ESHUTDOWN) 214 #define ESHUTDOWN 4099 215 #endif 216 217 /* time_t may be either 32 or 64 bits depending on the host OS, and 218 * can be either signed or unsigned, so we can't just hardcode a 219 * specific maximum value. This is not a C preprocessor constant, 220 * so you can't use TIME_MAX in an #ifdef, but for our purposes 221 * this isn't a problem. 222 */ 223 224 /* The macros TYPE_SIGNED, TYPE_WIDTH, and TYPE_MAXIMUM are from 225 * Gnulib, and are under the LGPL v2.1 or (at your option) any 226 * later version. 227 */ 228 229 /* True if the real type T is signed. */ 230 #define TYPE_SIGNED(t) (!((t)0 < (t)-1)) 231 232 /* The width in bits of the integer type or expression T. 233 * Padding bits are not supported. 234 */ 235 #define TYPE_WIDTH(t) (sizeof(t) * CHAR_BIT) 236 237 /* The maximum and minimum values for the integer type T. */ 238 #define TYPE_MAXIMUM(t) \ 239 ((t) (!TYPE_SIGNED(t) \ 240 ? (t)-1 \ 241 : ((((t)1 << (TYPE_WIDTH(t) - 2)) - 1) * 2 + 1))) 242 243 #ifndef TIME_MAX 244 #define TIME_MAX TYPE_MAXIMUM(time_t) 245 #endif 246 247 /* HOST_LONG_BITS is the size of a native pointer in bits. */ 248 #if UINTPTR_MAX == UINT32_MAX 249 # define HOST_LONG_BITS 32 250 #elif UINTPTR_MAX == UINT64_MAX 251 # define HOST_LONG_BITS 64 252 #else 253 # error Unknown pointer size 254 #endif 255 256 /* Mac OSX has a <stdint.h> bug that incorrectly defines SIZE_MAX with 257 * the wrong type. Our replacement isn't usable in preprocessor 258 * expressions, but it is sufficient for our needs. */ 259 #ifdef HAVE_BROKEN_SIZE_MAX 260 #undef SIZE_MAX 261 #define SIZE_MAX ((size_t)-1) 262 #endif 263 264 /* 265 * Two variations of MIN/MAX macros. The first is for runtime use, and 266 * evaluates arguments only once (so it is safe even with side 267 * effects), but will not work in constant contexts (such as array 268 * size declarations) because of the '{}'. The second is for constant 269 * expression use, where evaluating arguments twice is safe because 270 * the result is going to be constant anyway, but will not work in a 271 * runtime context because of a void expression where a value is 272 * expected. Thus, both gcc and clang will fail to compile if you use 273 * the wrong macro (even if the error may seem a bit cryptic). 274 * 275 * Note that neither form is usable as an #if condition; if you truly 276 * need to write conditional code that depends on a minimum or maximum 277 * determined by the pre-processor instead of the compiler, you'll 278 * have to open-code it. Sadly, Coverity is severely confused by the 279 * constant variants, so we have to dumb things down there. 280 */ 281 #undef MIN 282 #define MIN(a, b) \ 283 ({ \ 284 typeof(1 ? (a) : (b)) _a = (a), _b = (b); \ 285 _a < _b ? _a : _b; \ 286 }) 287 #undef MAX 288 #define MAX(a, b) \ 289 ({ \ 290 typeof(1 ? (a) : (b)) _a = (a), _b = (b); \ 291 _a > _b ? _a : _b; \ 292 }) 293 294 #ifdef __COVERITY__ 295 # define MIN_CONST(a, b) ((a) < (b) ? (a) : (b)) 296 # define MAX_CONST(a, b) ((a) > (b) ? (a) : (b)) 297 #else 298 # define MIN_CONST(a, b) \ 299 __builtin_choose_expr( \ 300 __builtin_constant_p(a) && __builtin_constant_p(b), \ 301 (a) < (b) ? (a) : (b), \ 302 ((void)0)) 303 # define MAX_CONST(a, b) \ 304 __builtin_choose_expr( \ 305 __builtin_constant_p(a) && __builtin_constant_p(b), \ 306 (a) > (b) ? (a) : (b), \ 307 ((void)0)) 308 #endif 309 310 /* 311 * Minimum function that returns zero only if both values are zero. 312 * Intended for use with unsigned values only. 313 */ 314 #ifndef MIN_NON_ZERO 315 #define MIN_NON_ZERO(a, b) \ 316 ({ \ 317 typeof(1 ? (a) : (b)) _a = (a), _b = (b); \ 318 _a == 0 ? _b : (_b == 0 || _b > _a) ? _a : _b; \ 319 }) 320 #endif 321 322 /* 323 * Round number down to multiple. Safe when m is not a power of 2 (see 324 * ROUND_DOWN for a faster version when a power of 2 is guaranteed). 325 */ 326 #define QEMU_ALIGN_DOWN(n, m) ((n) / (m) * (m)) 327 328 /* 329 * Round number up to multiple. Safe when m is not a power of 2 (see 330 * ROUND_UP for a faster version when a power of 2 is guaranteed). 331 */ 332 #define QEMU_ALIGN_UP(n, m) QEMU_ALIGN_DOWN((n) + (m) - 1, (m)) 333 334 /* Check if n is a multiple of m */ 335 #define QEMU_IS_ALIGNED(n, m) (((n) % (m)) == 0) 336 337 /* n-byte align pointer down */ 338 #define QEMU_ALIGN_PTR_DOWN(p, n) \ 339 ((typeof(p))QEMU_ALIGN_DOWN((uintptr_t)(p), (n))) 340 341 /* n-byte align pointer up */ 342 #define QEMU_ALIGN_PTR_UP(p, n) \ 343 ((typeof(p))QEMU_ALIGN_UP((uintptr_t)(p), (n))) 344 345 /* Check if pointer p is n-bytes aligned */ 346 #define QEMU_PTR_IS_ALIGNED(p, n) QEMU_IS_ALIGNED((uintptr_t)(p), (n)) 347 348 /* 349 * Round number down to multiple. Requires that d be a power of 2 (see 350 * QEMU_ALIGN_UP for a safer but slower version on arbitrary 351 * numbers); works even if d is a smaller type than n. 352 */ 353 #ifndef ROUND_DOWN 354 #define ROUND_DOWN(n, d) ((n) & -(0 ? (n) : (d))) 355 #endif 356 357 /* 358 * Round number up to multiple. Requires that d be a power of 2 (see 359 * QEMU_ALIGN_UP for a safer but slower version on arbitrary 360 * numbers); works even if d is a smaller type than n. 361 */ 362 #ifndef ROUND_UP 363 #define ROUND_UP(n, d) ROUND_DOWN((n) + (d) - 1, (d)) 364 #endif 365 366 #ifndef DIV_ROUND_UP 367 #define DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d)) 368 #endif 369 370 /* 371 * &(x)[0] is always a pointer - if it's same type as x then the argument is a 372 * pointer, not an array. 373 */ 374 #define QEMU_IS_ARRAY(x) (!__builtin_types_compatible_p(typeof(x), \ 375 typeof(&(x)[0]))) 376 #ifndef ARRAY_SIZE 377 #define ARRAY_SIZE(x) ((sizeof(x) / sizeof((x)[0])) + \ 378 QEMU_BUILD_BUG_ON_ZERO(!QEMU_IS_ARRAY(x))) 379 #endif 380 381 int qemu_daemon(int nochdir, int noclose); 382 void *qemu_anon_ram_alloc(size_t size, uint64_t *align, bool shared, 383 bool noreserve); 384 void qemu_anon_ram_free(void *ptr, size_t size); 385 386 #ifdef _WIN32 387 #define HAVE_CHARDEV_SERIAL 1 388 #elif defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 389 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) \ 390 || defined(__GLIBC__) || defined(__APPLE__) 391 #define HAVE_CHARDEV_SERIAL 1 392 #endif 393 394 #if defined(__linux__) || defined(__FreeBSD__) || \ 395 defined(__FreeBSD_kernel__) || defined(__DragonFly__) 396 #define HAVE_CHARDEV_PARPORT 1 397 #endif 398 399 #if defined(__HAIKU__) 400 #define SIGIO SIGPOLL 401 #endif 402 403 #ifdef HAVE_MADVISE_WITHOUT_PROTOTYPE 404 /* 405 * See MySQL bug #7156 (http://bugs.mysql.com/bug.php?id=7156) for discussion 406 * about Solaris missing the madvise() prototype. 407 */ 408 extern int madvise(char *, size_t, int); 409 #endif 410 411 #if defined(CONFIG_LINUX) 412 #ifndef BUS_MCEERR_AR 413 #define BUS_MCEERR_AR 4 414 #endif 415 #ifndef BUS_MCEERR_AO 416 #define BUS_MCEERR_AO 5 417 #endif 418 #endif 419 420 #if defined(__linux__) && \ 421 (defined(__x86_64__) || defined(__arm__) || defined(__aarch64__) \ 422 || defined(__powerpc64__)) 423 /* Use 2 MiB alignment so transparent hugepages can be used by KVM. 424 Valgrind does not support alignments larger than 1 MiB, 425 therefore we need special code which handles running on Valgrind. */ 426 # define QEMU_VMALLOC_ALIGN (512 * 4096) 427 #elif defined(__linux__) && defined(__s390x__) 428 /* Use 1 MiB (segment size) alignment so gmap can be used by KVM. */ 429 # define QEMU_VMALLOC_ALIGN (256 * 4096) 430 #elif defined(__linux__) && defined(__sparc__) 431 # define QEMU_VMALLOC_ALIGN MAX(qemu_real_host_page_size, SHMLBA) 432 #else 433 # define QEMU_VMALLOC_ALIGN qemu_real_host_page_size 434 #endif 435 436 #ifdef CONFIG_POSIX 437 struct qemu_signalfd_siginfo { 438 uint32_t ssi_signo; /* Signal number */ 439 int32_t ssi_errno; /* Error number (unused) */ 440 int32_t ssi_code; /* Signal code */ 441 uint32_t ssi_pid; /* PID of sender */ 442 uint32_t ssi_uid; /* Real UID of sender */ 443 int32_t ssi_fd; /* File descriptor (SIGIO) */ 444 uint32_t ssi_tid; /* Kernel timer ID (POSIX timers) */ 445 uint32_t ssi_band; /* Band event (SIGIO) */ 446 uint32_t ssi_overrun; /* POSIX timer overrun count */ 447 uint32_t ssi_trapno; /* Trap number that caused signal */ 448 int32_t ssi_status; /* Exit status or signal (SIGCHLD) */ 449 int32_t ssi_int; /* Integer sent by sigqueue(2) */ 450 uint64_t ssi_ptr; /* Pointer sent by sigqueue(2) */ 451 uint64_t ssi_utime; /* User CPU time consumed (SIGCHLD) */ 452 uint64_t ssi_stime; /* System CPU time consumed (SIGCHLD) */ 453 uint64_t ssi_addr; /* Address that generated signal 454 (for hardware-generated signals) */ 455 uint8_t pad[48]; /* Pad size to 128 bytes (allow for 456 additional fields in the future) */ 457 }; 458 459 int qemu_signalfd(const sigset_t *mask); 460 void sigaction_invoke(struct sigaction *action, 461 struct qemu_signalfd_siginfo *info); 462 #endif 463 464 /* 465 * Don't introduce new usage of this function, prefer the following 466 * qemu_open/qemu_create that take an "Error **errp" 467 */ 468 int qemu_open_old(const char *name, int flags, ...); 469 int qemu_open(const char *name, int flags, Error **errp); 470 int qemu_create(const char *name, int flags, mode_t mode, Error **errp); 471 int qemu_close(int fd); 472 int qemu_unlink(const char *name); 473 #ifndef _WIN32 474 int qemu_dup_flags(int fd, int flags); 475 int qemu_dup(int fd); 476 int qemu_lock_fd(int fd, int64_t start, int64_t len, bool exclusive); 477 int qemu_unlock_fd(int fd, int64_t start, int64_t len); 478 int qemu_lock_fd_test(int fd, int64_t start, int64_t len, bool exclusive); 479 bool qemu_has_ofd_lock(void); 480 #endif 481 482 #if defined(__HAIKU__) && defined(__i386__) 483 #define FMT_pid "%ld" 484 #elif defined(WIN64) 485 #define FMT_pid "%" PRId64 486 #else 487 #define FMT_pid "%d" 488 #endif 489 490 bool qemu_write_pidfile(const char *pidfile, Error **errp); 491 492 int qemu_get_thread_id(void); 493 494 #ifndef CONFIG_IOVEC 495 struct iovec { 496 void *iov_base; 497 size_t iov_len; 498 }; 499 /* 500 * Use the same value as Linux for now. 501 */ 502 #define IOV_MAX 1024 503 504 ssize_t readv(int fd, const struct iovec *iov, int iov_cnt); 505 ssize_t writev(int fd, const struct iovec *iov, int iov_cnt); 506 #endif 507 508 #ifdef _WIN32 509 static inline void qemu_timersub(const struct timeval *val1, 510 const struct timeval *val2, 511 struct timeval *res) 512 { 513 res->tv_sec = val1->tv_sec - val2->tv_sec; 514 if (val1->tv_usec < val2->tv_usec) { 515 res->tv_sec--; 516 res->tv_usec = val1->tv_usec - val2->tv_usec + 1000 * 1000; 517 } else { 518 res->tv_usec = val1->tv_usec - val2->tv_usec; 519 } 520 } 521 #else 522 #define qemu_timersub timersub 523 #endif 524 525 void qemu_set_cloexec(int fd); 526 527 void fips_set_state(bool requested); 528 bool fips_get_state(void); 529 530 /* Return a dynamically allocated pathname denoting a file or directory that is 531 * appropriate for storing local state. 532 * 533 * @relative_pathname need not start with a directory separator; one will be 534 * added automatically. 535 * 536 * The caller is responsible for releasing the value returned with g_free() 537 * after use. 538 */ 539 char *qemu_get_local_state_pathname(const char *relative_pathname); 540 541 /* Find program directory, and save it for later usage with 542 * qemu_get_exec_dir(). 543 * Try OS specific API first, if not working, parse from argv0. */ 544 void qemu_init_exec_dir(const char *argv0); 545 546 /* Get the saved exec dir. */ 547 const char *qemu_get_exec_dir(void); 548 549 /** 550 * qemu_getauxval: 551 * @type: the auxiliary vector key to lookup 552 * 553 * Search the auxiliary vector for @type, returning the value 554 * or 0 if @type is not present. 555 */ 556 unsigned long qemu_getauxval(unsigned long type); 557 558 void qemu_set_tty_echo(int fd, bool echo); 559 560 void os_mem_prealloc(int fd, char *area, size_t sz, int smp_cpus, 561 Error **errp); 562 563 /** 564 * qemu_get_pid_name: 565 * @pid: pid of a process 566 * 567 * For given @pid fetch its name. Caller is responsible for 568 * freeing the string when no longer needed. 569 * Returns allocated string on success, NULL on failure. 570 */ 571 char *qemu_get_pid_name(pid_t pid); 572 573 /** 574 * qemu_fork: 575 * 576 * A version of fork that avoids signal handler race 577 * conditions that can lead to child process getting 578 * signals that are otherwise only expected by the 579 * parent. It also resets all signal handlers to the 580 * default settings. 581 * 582 * Returns 0 to child process, pid number to parent 583 * or -1 on failure. 584 */ 585 pid_t qemu_fork(Error **errp); 586 587 /* Using intptr_t ensures that qemu_*_page_mask is sign-extended even 588 * when intptr_t is 32-bit and we are aligning a long long. 589 */ 590 extern uintptr_t qemu_real_host_page_size; 591 extern intptr_t qemu_real_host_page_mask; 592 593 /* 594 * After using getopt or getopt_long, if you need to parse another set 595 * of options, then you must reset optind. Unfortunately the way to 596 * do this varies between implementations of getopt. 597 */ 598 static inline void qemu_reset_optind(void) 599 { 600 #ifdef HAVE_OPTRESET 601 optind = 1; 602 optreset = 1; 603 #else 604 optind = 0; 605 #endif 606 } 607 608 /** 609 * qemu_get_host_name: 610 * @errp: Error object 611 * 612 * Operating system agnostic way of querying host name. 613 * 614 * Returns allocated hostname (caller should free), NULL on failure. 615 */ 616 char *qemu_get_host_name(Error **errp); 617 618 /** 619 * qemu_get_host_physmem: 620 * 621 * Operating system agnostic way of querying host memory. 622 * 623 * Returns amount of physical memory on the system. This is purely 624 * advisery and may return 0 if we can't work it out. At the other 625 * end we saturate to SIZE_MAX if you are lucky enough to have that 626 * much memory. 627 */ 628 size_t qemu_get_host_physmem(void); 629 630 /* 631 * Toggle write/execute on the pages marked MAP_JIT 632 * for the current thread. 633 */ 634 #if defined(MAC_OS_VERSION_11_0) && \ 635 MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_VERSION_11_0 636 static inline void qemu_thread_jit_execute(void) 637 { 638 pthread_jit_write_protect_np(true); 639 } 640 641 static inline void qemu_thread_jit_write(void) 642 { 643 pthread_jit_write_protect_np(false); 644 } 645 #else 646 static inline void qemu_thread_jit_write(void) {} 647 static inline void qemu_thread_jit_execute(void) {} 648 #endif 649 650 /** 651 * Platforms which do not support system() return ENOSYS 652 */ 653 #ifndef HAVE_SYSTEM_FUNCTION 654 #define system platform_does_not_support_system 655 static inline int platform_does_not_support_system(const char *command) 656 { 657 errno = ENOSYS; 658 return -1; 659 } 660 #endif /* !HAVE_SYSTEM_FUNCTION */ 661 662 #ifdef __cplusplus 663 } 664 #endif 665 666 #endif 667