xref: /qemu/include/qemu/osdep.h (revision fc7d2b45)
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.h"
33 #else
34 #include "exec/poison.h"
35 #endif
36 #ifdef __COVERITY__
37 /* Coverity does not like the new _Float* types that are used by
38  * recent glibc, and croaks on every single file that includes
39  * stdlib.h.  These typedefs are enough to please it.
40  *
41  * Note that these fix parse errors so they cannot be placed in
42  * scripts/coverity-model.c.
43  */
44 typedef float _Float32;
45 typedef double _Float32x;
46 typedef double _Float64;
47 typedef __float80 _Float64x;
48 typedef __float128 _Float128;
49 #endif
50 
51 #include "qemu/compiler.h"
52 
53 /* Older versions of C++ don't get definitions of various macros from
54  * stdlib.h unless we define these macros before first inclusion of
55  * that system header.
56  */
57 #ifndef __STDC_CONSTANT_MACROS
58 #define __STDC_CONSTANT_MACROS
59 #endif
60 #ifndef __STDC_LIMIT_MACROS
61 #define __STDC_LIMIT_MACROS
62 #endif
63 #ifndef __STDC_FORMAT_MACROS
64 #define __STDC_FORMAT_MACROS
65 #endif
66 
67 /* The following block of code temporarily renames the daemon() function so the
68  * compiler does not see the warning associated with it in stdlib.h on OSX
69  */
70 #ifdef __APPLE__
71 #define daemon qemu_fake_daemon_function
72 #include <stdlib.h>
73 #undef daemon
74 extern int daemon(int, int);
75 #endif
76 
77 #ifdef _WIN32
78 /* as defined in sdkddkver.h */
79 #ifndef _WIN32_WINNT
80 #define _WIN32_WINNT 0x0600 /* Vista */
81 #endif
82 /* reduces the number of implicitly included headers */
83 #ifndef WIN32_LEAN_AND_MEAN
84 #define WIN32_LEAN_AND_MEAN
85 #endif
86 #endif
87 
88 /* enable C99/POSIX format strings (needs mingw32-runtime 3.15 or later) */
89 #ifdef __MINGW32__
90 #define __USE_MINGW_ANSI_STDIO 1
91 #endif
92 
93 #include <stdarg.h>
94 #include <stddef.h>
95 #include <stdbool.h>
96 #include <stdint.h>
97 #include <sys/types.h>
98 #include <stdlib.h>
99 #include <stdio.h>
100 
101 #include <string.h>
102 #include <strings.h>
103 #include <inttypes.h>
104 #include <limits.h>
105 /* Put unistd.h before time.h as that triggers localtime_r/gmtime_r
106  * function availability on recentish Mingw-w64 platforms. */
107 #include <unistd.h>
108 #include <time.h>
109 #include <ctype.h>
110 #include <errno.h>
111 #include <fcntl.h>
112 #include <getopt.h>
113 #include <sys/stat.h>
114 #include <sys/time.h>
115 #include <assert.h>
116 /* setjmp must be declared before sysemu/os-win32.h
117  * because it is redefined there. */
118 #include <setjmp.h>
119 #include <signal.h>
120 
121 #ifdef __OpenBSD__
122 #include <sys/signal.h>
123 #endif
124 
125 #ifndef _WIN32
126 #include <sys/wait.h>
127 #else
128 #define WIFEXITED(x)   1
129 #define WEXITSTATUS(x) (x)
130 #endif
131 
132 #ifdef _WIN32
133 #include "sysemu/os-win32.h"
134 #endif
135 
136 #ifdef CONFIG_POSIX
137 #include "sysemu/os-posix.h"
138 #endif
139 
140 #include "glib-compat.h"
141 #include "qemu/typedefs.h"
142 
143 /*
144  * For mingw, as of v6.0.0, the function implementing the assert macro is
145  * not marked as noreturn, so the compiler cannot delete code following an
146  * assert(false) as unused.  We rely on this within the code base to delete
147  * code that is unreachable when features are disabled.
148  * All supported versions of Glib's g_assert() satisfy this requirement.
149  */
150 #ifdef __MINGW32__
151 #undef assert
152 #define assert(x)  g_assert(x)
153 #endif
154 
155 /*
156  * According to waitpid man page:
157  * WCOREDUMP
158  *  This  macro  is  not  specified  in POSIX.1-2001 and is not
159  *  available on some UNIX implementations (e.g., AIX, SunOS).
160  *  Therefore, enclose its use inside #ifdef WCOREDUMP ... #endif.
161  */
162 #ifndef WCOREDUMP
163 #define WCOREDUMP(status) 0
164 #endif
165 /*
166  * We have a lot of unaudited code that may fail in strange ways, or
167  * even be a security risk during migration, if you disable assertions
168  * at compile-time.  You may comment out these safety checks if you
169  * absolutely want to disable assertion overhead, but it is not
170  * supported upstream so the risk is all yours.  Meanwhile, please
171  * submit patches to remove any side-effects inside an assertion, or
172  * fixing error handling that should use Error instead of assert.
173  */
174 #ifdef NDEBUG
175 #error building with NDEBUG is not supported
176 #endif
177 #ifdef G_DISABLE_ASSERT
178 #error building with G_DISABLE_ASSERT is not supported
179 #endif
180 
181 #ifndef O_LARGEFILE
182 #define O_LARGEFILE 0
183 #endif
184 #ifndef O_BINARY
185 #define O_BINARY 0
186 #endif
187 #ifndef MAP_ANONYMOUS
188 #define MAP_ANONYMOUS MAP_ANON
189 #endif
190 #ifndef ENOMEDIUM
191 #define ENOMEDIUM ENODEV
192 #endif
193 #if !defined(ENOTSUP)
194 #define ENOTSUP 4096
195 #endif
196 #if !defined(ECANCELED)
197 #define ECANCELED 4097
198 #endif
199 #if !defined(EMEDIUMTYPE)
200 #define EMEDIUMTYPE 4098
201 #endif
202 #if !defined(ESHUTDOWN)
203 #define ESHUTDOWN 4099
204 #endif
205 
206 /* time_t may be either 32 or 64 bits depending on the host OS, and
207  * can be either signed or unsigned, so we can't just hardcode a
208  * specific maximum value. This is not a C preprocessor constant,
209  * so you can't use TIME_MAX in an #ifdef, but for our purposes
210  * this isn't a problem.
211  */
212 
213 /* The macros TYPE_SIGNED, TYPE_WIDTH, and TYPE_MAXIMUM are from
214  * Gnulib, and are under the LGPL v2.1 or (at your option) any
215  * later version.
216  */
217 
218 /* True if the real type T is signed.  */
219 #define TYPE_SIGNED(t) (!((t)0 < (t)-1))
220 
221 /* The width in bits of the integer type or expression T.
222  * Padding bits are not supported.
223  */
224 #define TYPE_WIDTH(t) (sizeof(t) * CHAR_BIT)
225 
226 /* The maximum and minimum values for the integer type T.  */
227 #define TYPE_MAXIMUM(t)                                                \
228   ((t) (!TYPE_SIGNED(t)                                                \
229         ? (t)-1                                                        \
230         : ((((t)1 << (TYPE_WIDTH(t) - 2)) - 1) * 2 + 1)))
231 
232 #ifndef TIME_MAX
233 #define TIME_MAX TYPE_MAXIMUM(time_t)
234 #endif
235 
236 /* HOST_LONG_BITS is the size of a native pointer in bits. */
237 #if UINTPTR_MAX == UINT32_MAX
238 # define HOST_LONG_BITS 32
239 #elif UINTPTR_MAX == UINT64_MAX
240 # define HOST_LONG_BITS 64
241 #else
242 # error Unknown pointer size
243 #endif
244 
245 /* Mac OSX has a <stdint.h> bug that incorrectly defines SIZE_MAX with
246  * the wrong type. Our replacement isn't usable in preprocessor
247  * expressions, but it is sufficient for our needs. */
248 #if defined(HAVE_BROKEN_SIZE_MAX) && HAVE_BROKEN_SIZE_MAX
249 #undef SIZE_MAX
250 #define SIZE_MAX ((size_t)-1)
251 #endif
252 
253 #ifndef MIN
254 #define MIN(a, b) (((a) < (b)) ? (a) : (b))
255 #endif
256 #ifndef MAX
257 #define MAX(a, b) (((a) > (b)) ? (a) : (b))
258 #endif
259 
260 /* Minimum function that returns zero only iff both values are zero.
261  * Intended for use with unsigned values only. */
262 #ifndef MIN_NON_ZERO
263 #define MIN_NON_ZERO(a, b) ((a) == 0 ? (b) : \
264                                 ((b) == 0 ? (a) : (MIN(a, b))))
265 #endif
266 
267 /* Round number down to multiple */
268 #define QEMU_ALIGN_DOWN(n, m) ((n) / (m) * (m))
269 
270 /* Round number up to multiple. Safe when m is not a power of 2 (see
271  * ROUND_UP for a faster version when a power of 2 is guaranteed) */
272 #define QEMU_ALIGN_UP(n, m) QEMU_ALIGN_DOWN((n) + (m) - 1, (m))
273 
274 /* Check if n is a multiple of m */
275 #define QEMU_IS_ALIGNED(n, m) (((n) % (m)) == 0)
276 
277 /* n-byte align pointer down */
278 #define QEMU_ALIGN_PTR_DOWN(p, n) \
279     ((typeof(p))QEMU_ALIGN_DOWN((uintptr_t)(p), (n)))
280 
281 /* n-byte align pointer up */
282 #define QEMU_ALIGN_PTR_UP(p, n) \
283     ((typeof(p))QEMU_ALIGN_UP((uintptr_t)(p), (n)))
284 
285 /* Check if pointer p is n-bytes aligned */
286 #define QEMU_PTR_IS_ALIGNED(p, n) QEMU_IS_ALIGNED((uintptr_t)(p), (n))
287 
288 /* Round number up to multiple. Requires that d be a power of 2 (see
289  * QEMU_ALIGN_UP for a safer but slower version on arbitrary
290  * numbers); works even if d is a smaller type than n.  */
291 #ifndef ROUND_UP
292 #define ROUND_UP(n, d) (((n) + (d) - 1) & -(0 ? (n) : (d)))
293 #endif
294 
295 #ifndef DIV_ROUND_UP
296 #define DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d))
297 #endif
298 
299 /*
300  * &(x)[0] is always a pointer - if it's same type as x then the argument is a
301  * pointer, not an array.
302  */
303 #define QEMU_IS_ARRAY(x) (!__builtin_types_compatible_p(typeof(x), \
304                                                         typeof(&(x)[0])))
305 #ifndef ARRAY_SIZE
306 #define ARRAY_SIZE(x) ((sizeof(x) / sizeof((x)[0])) + \
307                        QEMU_BUILD_BUG_ON_ZERO(!QEMU_IS_ARRAY(x)))
308 #endif
309 
310 int qemu_daemon(int nochdir, int noclose);
311 void *qemu_try_memalign(size_t alignment, size_t size);
312 void *qemu_memalign(size_t alignment, size_t size);
313 void *qemu_anon_ram_alloc(size_t size, uint64_t *align, bool shared);
314 void qemu_vfree(void *ptr);
315 void qemu_anon_ram_free(void *ptr, size_t size);
316 
317 #define QEMU_MADV_INVALID -1
318 
319 #if defined(CONFIG_MADVISE)
320 
321 #define QEMU_MADV_WILLNEED  MADV_WILLNEED
322 #define QEMU_MADV_DONTNEED  MADV_DONTNEED
323 #ifdef MADV_DONTFORK
324 #define QEMU_MADV_DONTFORK  MADV_DONTFORK
325 #else
326 #define QEMU_MADV_DONTFORK  QEMU_MADV_INVALID
327 #endif
328 #ifdef MADV_MERGEABLE
329 #define QEMU_MADV_MERGEABLE MADV_MERGEABLE
330 #else
331 #define QEMU_MADV_MERGEABLE QEMU_MADV_INVALID
332 #endif
333 #ifdef MADV_UNMERGEABLE
334 #define QEMU_MADV_UNMERGEABLE MADV_UNMERGEABLE
335 #else
336 #define QEMU_MADV_UNMERGEABLE QEMU_MADV_INVALID
337 #endif
338 #ifdef MADV_DODUMP
339 #define QEMU_MADV_DODUMP MADV_DODUMP
340 #else
341 #define QEMU_MADV_DODUMP QEMU_MADV_INVALID
342 #endif
343 #ifdef MADV_DONTDUMP
344 #define QEMU_MADV_DONTDUMP MADV_DONTDUMP
345 #else
346 #define QEMU_MADV_DONTDUMP QEMU_MADV_INVALID
347 #endif
348 #ifdef MADV_HUGEPAGE
349 #define QEMU_MADV_HUGEPAGE MADV_HUGEPAGE
350 #else
351 #define QEMU_MADV_HUGEPAGE QEMU_MADV_INVALID
352 #endif
353 #ifdef MADV_NOHUGEPAGE
354 #define QEMU_MADV_NOHUGEPAGE MADV_NOHUGEPAGE
355 #else
356 #define QEMU_MADV_NOHUGEPAGE QEMU_MADV_INVALID
357 #endif
358 #ifdef MADV_REMOVE
359 #define QEMU_MADV_REMOVE MADV_REMOVE
360 #else
361 #define QEMU_MADV_REMOVE QEMU_MADV_INVALID
362 #endif
363 
364 #elif defined(CONFIG_POSIX_MADVISE)
365 
366 #define QEMU_MADV_WILLNEED  POSIX_MADV_WILLNEED
367 #define QEMU_MADV_DONTNEED  POSIX_MADV_DONTNEED
368 #define QEMU_MADV_DONTFORK  QEMU_MADV_INVALID
369 #define QEMU_MADV_MERGEABLE QEMU_MADV_INVALID
370 #define QEMU_MADV_UNMERGEABLE QEMU_MADV_INVALID
371 #define QEMU_MADV_DODUMP QEMU_MADV_INVALID
372 #define QEMU_MADV_DONTDUMP QEMU_MADV_INVALID
373 #define QEMU_MADV_HUGEPAGE  QEMU_MADV_INVALID
374 #define QEMU_MADV_NOHUGEPAGE  QEMU_MADV_INVALID
375 #define QEMU_MADV_REMOVE QEMU_MADV_INVALID
376 
377 #else /* no-op */
378 
379 #define QEMU_MADV_WILLNEED  QEMU_MADV_INVALID
380 #define QEMU_MADV_DONTNEED  QEMU_MADV_INVALID
381 #define QEMU_MADV_DONTFORK  QEMU_MADV_INVALID
382 #define QEMU_MADV_MERGEABLE QEMU_MADV_INVALID
383 #define QEMU_MADV_UNMERGEABLE QEMU_MADV_INVALID
384 #define QEMU_MADV_DODUMP QEMU_MADV_INVALID
385 #define QEMU_MADV_DONTDUMP QEMU_MADV_INVALID
386 #define QEMU_MADV_HUGEPAGE  QEMU_MADV_INVALID
387 #define QEMU_MADV_NOHUGEPAGE  QEMU_MADV_INVALID
388 #define QEMU_MADV_REMOVE QEMU_MADV_INVALID
389 
390 #endif
391 
392 #ifdef _WIN32
393 #define HAVE_CHARDEV_SERIAL 1
394 #elif defined(__linux__) || defined(__sun__) || defined(__FreeBSD__)    \
395     || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) \
396     || defined(__GLIBC__)
397 #define HAVE_CHARDEV_SERIAL 1
398 #endif
399 
400 #if defined(__linux__) || defined(__FreeBSD__) ||               \
401     defined(__FreeBSD_kernel__) || defined(__DragonFly__)
402 #define HAVE_CHARDEV_PARPORT 1
403 #endif
404 
405 #if defined(CONFIG_LINUX)
406 #ifndef BUS_MCEERR_AR
407 #define BUS_MCEERR_AR 4
408 #endif
409 #ifndef BUS_MCEERR_AO
410 #define BUS_MCEERR_AO 5
411 #endif
412 #endif
413 
414 #if defined(__linux__) && \
415     (defined(__x86_64__) || defined(__arm__) || defined(__aarch64__) \
416      || defined(__powerpc64__))
417    /* Use 2 MiB alignment so transparent hugepages can be used by KVM.
418       Valgrind does not support alignments larger than 1 MiB,
419       therefore we need special code which handles running on Valgrind. */
420 #  define QEMU_VMALLOC_ALIGN (512 * 4096)
421 #elif defined(__linux__) && defined(__s390x__)
422    /* Use 1 MiB (segment size) alignment so gmap can be used by KVM. */
423 #  define QEMU_VMALLOC_ALIGN (256 * 4096)
424 #elif defined(__linux__) && defined(__sparc__)
425 #include <sys/shm.h>
426 #  define QEMU_VMALLOC_ALIGN MAX(getpagesize(), SHMLBA)
427 #else
428 #  define QEMU_VMALLOC_ALIGN getpagesize()
429 #endif
430 
431 #ifdef CONFIG_POSIX
432 struct qemu_signalfd_siginfo {
433     uint32_t ssi_signo;   /* Signal number */
434     int32_t  ssi_errno;   /* Error number (unused) */
435     int32_t  ssi_code;    /* Signal code */
436     uint32_t ssi_pid;     /* PID of sender */
437     uint32_t ssi_uid;     /* Real UID of sender */
438     int32_t  ssi_fd;      /* File descriptor (SIGIO) */
439     uint32_t ssi_tid;     /* Kernel timer ID (POSIX timers) */
440     uint32_t ssi_band;    /* Band event (SIGIO) */
441     uint32_t ssi_overrun; /* POSIX timer overrun count */
442     uint32_t ssi_trapno;  /* Trap number that caused signal */
443     int32_t  ssi_status;  /* Exit status or signal (SIGCHLD) */
444     int32_t  ssi_int;     /* Integer sent by sigqueue(2) */
445     uint64_t ssi_ptr;     /* Pointer sent by sigqueue(2) */
446     uint64_t ssi_utime;   /* User CPU time consumed (SIGCHLD) */
447     uint64_t ssi_stime;   /* System CPU time consumed (SIGCHLD) */
448     uint64_t ssi_addr;    /* Address that generated signal
449                              (for hardware-generated signals) */
450     uint8_t  pad[48];     /* Pad size to 128 bytes (allow for
451                              additional fields in the future) */
452 };
453 
454 int qemu_signalfd(const sigset_t *mask);
455 void sigaction_invoke(struct sigaction *action,
456                       struct qemu_signalfd_siginfo *info);
457 #endif
458 
459 int qemu_madvise(void *addr, size_t len, int advice);
460 int qemu_mprotect_rwx(void *addr, size_t size);
461 int qemu_mprotect_none(void *addr, size_t size);
462 
463 int qemu_open(const char *name, int flags, ...);
464 int qemu_close(int fd);
465 #ifndef _WIN32
466 int qemu_dup(int fd);
467 #endif
468 int qemu_lock_fd(int fd, int64_t start, int64_t len, bool exclusive);
469 int qemu_unlock_fd(int fd, int64_t start, int64_t len);
470 int qemu_lock_fd_test(int fd, int64_t start, int64_t len, bool exclusive);
471 bool qemu_has_ofd_lock(void);
472 
473 #if defined(__HAIKU__) && defined(__i386__)
474 #define FMT_pid "%ld"
475 #elif defined(WIN64)
476 #define FMT_pid "%" PRId64
477 #else
478 #define FMT_pid "%d"
479 #endif
480 
481 bool qemu_write_pidfile(const char *pidfile, Error **errp);
482 
483 int qemu_get_thread_id(void);
484 
485 #ifndef CONFIG_IOVEC
486 struct iovec {
487     void *iov_base;
488     size_t iov_len;
489 };
490 /*
491  * Use the same value as Linux for now.
492  */
493 #define IOV_MAX 1024
494 
495 ssize_t readv(int fd, const struct iovec *iov, int iov_cnt);
496 ssize_t writev(int fd, const struct iovec *iov, int iov_cnt);
497 #else
498 #include <sys/uio.h>
499 #endif
500 
501 #ifdef _WIN32
502 static inline void qemu_timersub(const struct timeval *val1,
503                                  const struct timeval *val2,
504                                  struct timeval *res)
505 {
506     res->tv_sec = val1->tv_sec - val2->tv_sec;
507     if (val1->tv_usec < val2->tv_usec) {
508         res->tv_sec--;
509         res->tv_usec = val1->tv_usec - val2->tv_usec + 1000 * 1000;
510     } else {
511         res->tv_usec = val1->tv_usec - val2->tv_usec;
512     }
513 }
514 #else
515 #define qemu_timersub timersub
516 #endif
517 
518 void qemu_set_cloexec(int fd);
519 
520 /* Starting on QEMU 2.5, qemu_hw_version() returns "2.5+" by default
521  * instead of QEMU_VERSION, so setting hw_version on MachineClass
522  * is no longer mandatory.
523  *
524  * Do NOT change this string, or it will break compatibility on all
525  * machine classes that don't set hw_version.
526  */
527 #define QEMU_HW_VERSION "2.5+"
528 
529 /* QEMU "hardware version" setting. Used to replace code that exposed
530  * QEMU_VERSION to guests in the past and need to keep compatibility.
531  * Do not use qemu_hw_version() in new code.
532  */
533 void qemu_set_hw_version(const char *);
534 const char *qemu_hw_version(void);
535 
536 void fips_set_state(bool requested);
537 bool fips_get_state(void);
538 
539 /* Return a dynamically allocated pathname denoting a file or directory that is
540  * appropriate for storing local state.
541  *
542  * @relative_pathname need not start with a directory separator; one will be
543  * added automatically.
544  *
545  * The caller is responsible for releasing the value returned with g_free()
546  * after use.
547  */
548 char *qemu_get_local_state_pathname(const char *relative_pathname);
549 
550 /* Find program directory, and save it for later usage with
551  * qemu_get_exec_dir().
552  * Try OS specific API first, if not working, parse from argv0. */
553 void qemu_init_exec_dir(const char *argv0);
554 
555 /* Get the saved exec dir.
556  * Caller needs to release the returned string by g_free() */
557 char *qemu_get_exec_dir(void);
558 
559 /**
560  * qemu_getauxval:
561  * @type: the auxiliary vector key to lookup
562  *
563  * Search the auxiliary vector for @type, returning the value
564  * or 0 if @type is not present.
565  */
566 unsigned long qemu_getauxval(unsigned long type);
567 
568 void qemu_set_tty_echo(int fd, bool echo);
569 
570 void os_mem_prealloc(int fd, char *area, size_t sz, int smp_cpus,
571                      Error **errp);
572 
573 /**
574  * qemu_get_pmem_size:
575  * @filename: path to a pmem file
576  * @errp: pointer to a NULL-initialized error object
577  *
578  * Determine the size of a persistent memory file.  Besides supporting files on
579  * DAX file systems, this function also supports Linux devdax character
580  * devices.
581  *
582  * Returns: the size or 0 on failure
583  */
584 uint64_t qemu_get_pmem_size(const char *filename, Error **errp);
585 
586 /**
587  * qemu_get_pid_name:
588  * @pid: pid of a process
589  *
590  * For given @pid fetch its name. Caller is responsible for
591  * freeing the string when no longer needed.
592  * Returns allocated string on success, NULL on failure.
593  */
594 char *qemu_get_pid_name(pid_t pid);
595 
596 /**
597  * qemu_fork:
598  *
599  * A version of fork that avoids signal handler race
600  * conditions that can lead to child process getting
601  * signals that are otherwise only expected by the
602  * parent. It also resets all signal handlers to the
603  * default settings.
604  *
605  * Returns 0 to child process, pid number to parent
606  * or -1 on failure.
607  */
608 pid_t qemu_fork(Error **errp);
609 
610 /* Using intptr_t ensures that qemu_*_page_mask is sign-extended even
611  * when intptr_t is 32-bit and we are aligning a long long.
612  */
613 extern uintptr_t qemu_real_host_page_size;
614 extern intptr_t qemu_real_host_page_mask;
615 
616 extern int qemu_icache_linesize;
617 extern int qemu_icache_linesize_log;
618 extern int qemu_dcache_linesize;
619 extern int qemu_dcache_linesize_log;
620 
621 /*
622  * After using getopt or getopt_long, if you need to parse another set
623  * of options, then you must reset optind.  Unfortunately the way to
624  * do this varies between implementations of getopt.
625  */
626 static inline void qemu_reset_optind(void)
627 {
628 #ifdef HAVE_OPTRESET
629     optind = 1;
630     optreset = 1;
631 #else
632     optind = 0;
633 #endif
634 }
635 
636 #endif
637