xref: /openbmc/qemu/util/oslib-win32.c (revision 0b8f7448)
1 /*
2  * os-win32.c
3  *
4  * Copyright (c) 2003-2008 Fabrice Bellard
5  * Copyright (c) 2010-2016 Red Hat, Inc.
6  *
7  * QEMU library functions for win32 which are shared between QEMU and
8  * the QEMU tools.
9  *
10  * Permission is hereby granted, free of charge, to any person obtaining a copy
11  * of this software and associated documentation files (the "Software"), to deal
12  * in the Software without restriction, including without limitation the rights
13  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
14  * copies of the Software, and to permit persons to whom the Software is
15  * furnished to do so, subject to the following conditions:
16  *
17  * The above copyright notice and this permission notice shall be included in
18  * all copies or substantial portions of the Software.
19  *
20  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
21  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
22  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
23  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
24  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
25  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
26  * THE SOFTWARE.
27  *
28  * The implementation of g_poll (functions poll_rest, g_poll) at the end of
29  * this file are based on code from GNOME glib-2 and use a different license,
30  * see the license comment there.
31  */
32 #include "qemu/osdep.h"
33 #include <windows.h>
34 #include "qapi/error.h"
35 #include "sysemu/sysemu.h"
36 #include "qemu/main-loop.h"
37 #include "trace.h"
38 #include "qemu/sockets.h"
39 #include "qemu/cutils.h"
40 
41 /* this must come after including "trace.h" */
42 #include <shlobj.h>
43 
44 void *qemu_oom_check(void *ptr)
45 {
46     if (ptr == NULL) {
47         fprintf(stderr, "Failed to allocate memory: %lu\n", GetLastError());
48         abort();
49     }
50     return ptr;
51 }
52 
53 void *qemu_try_memalign(size_t alignment, size_t size)
54 {
55     void *ptr;
56 
57     if (!size) {
58         abort();
59     }
60     ptr = VirtualAlloc(NULL, size, MEM_COMMIT, PAGE_READWRITE);
61     trace_qemu_memalign(alignment, size, ptr);
62     return ptr;
63 }
64 
65 void *qemu_memalign(size_t alignment, size_t size)
66 {
67     return qemu_oom_check(qemu_try_memalign(alignment, size));
68 }
69 
70 static int get_allocation_granularity(void)
71 {
72     SYSTEM_INFO system_info;
73 
74     GetSystemInfo(&system_info);
75     return system_info.dwAllocationGranularity;
76 }
77 
78 void *qemu_anon_ram_alloc(size_t size, uint64_t *align, bool shared)
79 {
80     void *ptr;
81 
82     ptr = VirtualAlloc(NULL, size, MEM_COMMIT, PAGE_READWRITE);
83     trace_qemu_anon_ram_alloc(size, ptr);
84 
85     if (ptr && align) {
86         *align = MAX(get_allocation_granularity(), getpagesize());
87     }
88     return ptr;
89 }
90 
91 void qemu_vfree(void *ptr)
92 {
93     trace_qemu_vfree(ptr);
94     if (ptr) {
95         VirtualFree(ptr, 0, MEM_RELEASE);
96     }
97 }
98 
99 void qemu_anon_ram_free(void *ptr, size_t size)
100 {
101     trace_qemu_anon_ram_free(ptr, size);
102     if (ptr) {
103         VirtualFree(ptr, 0, MEM_RELEASE);
104     }
105 }
106 
107 #ifndef CONFIG_LOCALTIME_R
108 /* FIXME: add proper locking */
109 struct tm *gmtime_r(const time_t *timep, struct tm *result)
110 {
111     struct tm *p = gmtime(timep);
112     memset(result, 0, sizeof(*result));
113     if (p) {
114         *result = *p;
115         p = result;
116     }
117     return p;
118 }
119 
120 /* FIXME: add proper locking */
121 struct tm *localtime_r(const time_t *timep, struct tm *result)
122 {
123     struct tm *p = localtime(timep);
124     memset(result, 0, sizeof(*result));
125     if (p) {
126         *result = *p;
127         p = result;
128     }
129     return p;
130 }
131 #endif /* CONFIG_LOCALTIME_R */
132 
133 void qemu_set_block(int fd)
134 {
135     unsigned long opt = 0;
136     WSAEventSelect(fd, NULL, 0);
137     ioctlsocket(fd, FIONBIO, &opt);
138 }
139 
140 void qemu_set_nonblock(int fd)
141 {
142     unsigned long opt = 1;
143     ioctlsocket(fd, FIONBIO, &opt);
144     qemu_fd_register(fd);
145 }
146 
147 int socket_set_fast_reuse(int fd)
148 {
149     /* Enabling the reuse of an endpoint that was used by a socket still in
150      * TIME_WAIT state is usually performed by setting SO_REUSEADDR. On Windows
151      * fast reuse is the default and SO_REUSEADDR does strange things. So we
152      * don't have to do anything here. More info can be found at:
153      * http://msdn.microsoft.com/en-us/library/windows/desktop/ms740621.aspx */
154     return 0;
155 }
156 
157 
158 static int socket_error(void)
159 {
160     switch (WSAGetLastError()) {
161     case 0:
162         return 0;
163     case WSAEINTR:
164         return EINTR;
165     case WSAEINVAL:
166         return EINVAL;
167     case WSA_INVALID_HANDLE:
168         return EBADF;
169     case WSA_NOT_ENOUGH_MEMORY:
170         return ENOMEM;
171     case WSA_INVALID_PARAMETER:
172         return EINVAL;
173     case WSAENAMETOOLONG:
174         return ENAMETOOLONG;
175     case WSAENOTEMPTY:
176         return ENOTEMPTY;
177     case WSAEWOULDBLOCK:
178          /* not using EWOULDBLOCK as we don't want code to have
179           * to check both EWOULDBLOCK and EAGAIN */
180         return EAGAIN;
181     case WSAEINPROGRESS:
182         return EINPROGRESS;
183     case WSAEALREADY:
184         return EALREADY;
185     case WSAENOTSOCK:
186         return ENOTSOCK;
187     case WSAEDESTADDRREQ:
188         return EDESTADDRREQ;
189     case WSAEMSGSIZE:
190         return EMSGSIZE;
191     case WSAEPROTOTYPE:
192         return EPROTOTYPE;
193     case WSAENOPROTOOPT:
194         return ENOPROTOOPT;
195     case WSAEPROTONOSUPPORT:
196         return EPROTONOSUPPORT;
197     case WSAEOPNOTSUPP:
198         return EOPNOTSUPP;
199     case WSAEAFNOSUPPORT:
200         return EAFNOSUPPORT;
201     case WSAEADDRINUSE:
202         return EADDRINUSE;
203     case WSAEADDRNOTAVAIL:
204         return EADDRNOTAVAIL;
205     case WSAENETDOWN:
206         return ENETDOWN;
207     case WSAENETUNREACH:
208         return ENETUNREACH;
209     case WSAENETRESET:
210         return ENETRESET;
211     case WSAECONNABORTED:
212         return ECONNABORTED;
213     case WSAECONNRESET:
214         return ECONNRESET;
215     case WSAENOBUFS:
216         return ENOBUFS;
217     case WSAEISCONN:
218         return EISCONN;
219     case WSAENOTCONN:
220         return ENOTCONN;
221     case WSAETIMEDOUT:
222         return ETIMEDOUT;
223     case WSAECONNREFUSED:
224         return ECONNREFUSED;
225     case WSAELOOP:
226         return ELOOP;
227     case WSAEHOSTUNREACH:
228         return EHOSTUNREACH;
229     default:
230         return EIO;
231     }
232 }
233 
234 int inet_aton(const char *cp, struct in_addr *ia)
235 {
236     uint32_t addr = inet_addr(cp);
237     if (addr == 0xffffffff) {
238         return 0;
239     }
240     ia->s_addr = addr;
241     return 1;
242 }
243 
244 void qemu_set_cloexec(int fd)
245 {
246 }
247 
248 /* Offset between 1/1/1601 and 1/1/1970 in 100 nanosec units */
249 #define _W32_FT_OFFSET (116444736000000000ULL)
250 
251 int qemu_gettimeofday(qemu_timeval *tp)
252 {
253   union {
254     unsigned long long ns100; /*time since 1 Jan 1601 in 100ns units */
255     FILETIME ft;
256   }  _now;
257 
258   if(tp) {
259       GetSystemTimeAsFileTime (&_now.ft);
260       tp->tv_usec=(long)((_now.ns100 / 10ULL) % 1000000ULL );
261       tp->tv_sec= (long)((_now.ns100 - _W32_FT_OFFSET) / 10000000ULL);
262   }
263   /* Always return 0 as per Open Group Base Specifications Issue 6.
264      Do not set errno on error.  */
265   return 0;
266 }
267 
268 int qemu_get_thread_id(void)
269 {
270     return GetCurrentThreadId();
271 }
272 
273 char *
274 qemu_get_local_state_pathname(const char *relative_pathname)
275 {
276     HRESULT result;
277     char base_path[MAX_PATH+1] = "";
278 
279     result = SHGetFolderPath(NULL, CSIDL_COMMON_APPDATA, NULL,
280                              /* SHGFP_TYPE_CURRENT */ 0, base_path);
281     if (result != S_OK) {
282         /* misconfigured environment */
283         g_critical("CSIDL_COMMON_APPDATA unavailable: %ld", (long)result);
284         abort();
285     }
286     return g_strdup_printf("%s" G_DIR_SEPARATOR_S "%s", base_path,
287                            relative_pathname);
288 }
289 
290 void qemu_set_tty_echo(int fd, bool echo)
291 {
292     HANDLE handle = (HANDLE)_get_osfhandle(fd);
293     DWORD dwMode = 0;
294 
295     if (handle == INVALID_HANDLE_VALUE) {
296         return;
297     }
298 
299     GetConsoleMode(handle, &dwMode);
300 
301     if (echo) {
302         SetConsoleMode(handle, dwMode | ENABLE_ECHO_INPUT | ENABLE_LINE_INPUT);
303     } else {
304         SetConsoleMode(handle,
305                        dwMode & ~(ENABLE_ECHO_INPUT | ENABLE_LINE_INPUT));
306     }
307 }
308 
309 static char exec_dir[PATH_MAX];
310 
311 void qemu_init_exec_dir(const char *argv0)
312 {
313 
314     char *p;
315     char buf[MAX_PATH];
316     DWORD len;
317 
318     len = GetModuleFileName(NULL, buf, sizeof(buf) - 1);
319     if (len == 0) {
320         return;
321     }
322 
323     buf[len] = 0;
324     p = buf + len - 1;
325     while (p != buf && *p != '\\') {
326         p--;
327     }
328     *p = 0;
329     if (access(buf, R_OK) == 0) {
330         pstrcpy(exec_dir, sizeof(exec_dir), buf);
331     }
332 }
333 
334 char *qemu_get_exec_dir(void)
335 {
336     return g_strdup(exec_dir);
337 }
338 
339 #if !GLIB_CHECK_VERSION(2, 50, 0)
340 /*
341  * The original implementation of g_poll from glib has a problem on Windows
342  * when using timeouts < 10 ms.
343  *
344  * Whenever g_poll is called with timeout < 10 ms, it does a quick poll instead
345  * of wait. This causes significant performance degradation of QEMU.
346  *
347  * The following code is a copy of the original code from glib/gpoll.c
348  * (glib commit 20f4d1820b8d4d0fc4447188e33efffd6d4a88d8 from 2014-02-19).
349  * Some debug code was removed and the code was reformatted.
350  * All other code modifications are marked with 'QEMU'.
351  */
352 
353 /*
354  * gpoll.c: poll(2) abstraction
355  * Copyright 1998 Owen Taylor
356  * Copyright 2008 Red Hat, Inc.
357  *
358  * This library is free software; you can redistribute it and/or
359  * modify it under the terms of the GNU Lesser General Public
360  * License as published by the Free Software Foundation; either
361  * version 2 of the License, or (at your option) any later version.
362  *
363  * This library is distributed in the hope that it will be useful,
364  * but WITHOUT ANY WARRANTY; without even the implied warranty of
365  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
366  * Lesser General Public License for more details.
367  *
368  * You should have received a copy of the GNU Lesser General Public
369  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
370  */
371 
372 static int poll_rest(gboolean poll_msgs, HANDLE *handles, gint nhandles,
373                      GPollFD *fds, guint nfds, gint timeout)
374 {
375     DWORD ready;
376     GPollFD *f;
377     int recursed_result;
378 
379     if (poll_msgs) {
380         /* Wait for either messages or handles
381          * -> Use MsgWaitForMultipleObjectsEx
382          */
383         ready = MsgWaitForMultipleObjectsEx(nhandles, handles, timeout,
384                                             QS_ALLINPUT, MWMO_ALERTABLE);
385 
386         if (ready == WAIT_FAILED) {
387             gchar *emsg = g_win32_error_message(GetLastError());
388             g_warning("MsgWaitForMultipleObjectsEx failed: %s", emsg);
389             g_free(emsg);
390         }
391     } else if (nhandles == 0) {
392         /* No handles to wait for, just the timeout */
393         if (timeout == INFINITE) {
394             ready = WAIT_FAILED;
395         } else {
396             SleepEx(timeout, TRUE);
397             ready = WAIT_TIMEOUT;
398         }
399     } else {
400         /* Wait for just handles
401          * -> Use WaitForMultipleObjectsEx
402          */
403         ready =
404             WaitForMultipleObjectsEx(nhandles, handles, FALSE, timeout, TRUE);
405         if (ready == WAIT_FAILED) {
406             gchar *emsg = g_win32_error_message(GetLastError());
407             g_warning("WaitForMultipleObjectsEx failed: %s", emsg);
408             g_free(emsg);
409         }
410     }
411 
412     if (ready == WAIT_FAILED) {
413         return -1;
414     } else if (ready == WAIT_TIMEOUT || ready == WAIT_IO_COMPLETION) {
415         return 0;
416     } else if (poll_msgs && ready == WAIT_OBJECT_0 + nhandles) {
417         for (f = fds; f < &fds[nfds]; ++f) {
418             if (f->fd == G_WIN32_MSG_HANDLE && f->events & G_IO_IN) {
419                 f->revents |= G_IO_IN;
420             }
421         }
422 
423         /* If we have a timeout, or no handles to poll, be satisfied
424          * with just noticing we have messages waiting.
425          */
426         if (timeout != 0 || nhandles == 0) {
427             return 1;
428         }
429 
430         /* If no timeout and handles to poll, recurse to poll them,
431          * too.
432          */
433         recursed_result = poll_rest(FALSE, handles, nhandles, fds, nfds, 0);
434         return (recursed_result == -1) ? -1 : 1 + recursed_result;
435     } else if (/* QEMU: removed the following unneeded statement which causes
436                 * a compiler warning: ready >= WAIT_OBJECT_0 && */
437                ready < WAIT_OBJECT_0 + nhandles) {
438         for (f = fds; f < &fds[nfds]; ++f) {
439             if ((HANDLE) f->fd == handles[ready - WAIT_OBJECT_0]) {
440                 f->revents = f->events;
441             }
442         }
443 
444         /* If no timeout and polling several handles, recurse to poll
445          * the rest of them.
446          */
447         if (timeout == 0 && nhandles > 1) {
448             /* Remove the handle that fired */
449             int i;
450             for (i = ready - WAIT_OBJECT_0 + 1; i < nhandles; i++) {
451                 handles[i-1] = handles[i];
452             }
453             nhandles--;
454             recursed_result = poll_rest(FALSE, handles, nhandles, fds, nfds, 0);
455             return (recursed_result == -1) ? -1 : 1 + recursed_result;
456         }
457         return 1;
458     }
459 
460     return 0;
461 }
462 
463 gint g_poll(GPollFD *fds, guint nfds, gint timeout)
464 {
465     HANDLE handles[MAXIMUM_WAIT_OBJECTS];
466     gboolean poll_msgs = FALSE;
467     GPollFD *f;
468     gint nhandles = 0;
469     int retval;
470 
471     for (f = fds; f < &fds[nfds]; ++f) {
472         if (f->fd == G_WIN32_MSG_HANDLE && (f->events & G_IO_IN)) {
473             poll_msgs = TRUE;
474         } else if (f->fd > 0) {
475             /* Don't add the same handle several times into the array, as
476              * docs say that is not allowed, even if it actually does seem
477              * to work.
478              */
479             gint i;
480 
481             for (i = 0; i < nhandles; i++) {
482                 if (handles[i] == (HANDLE) f->fd) {
483                     break;
484                 }
485             }
486 
487             if (i == nhandles) {
488                 if (nhandles == MAXIMUM_WAIT_OBJECTS) {
489                     g_warning("Too many handles to wait for!\n");
490                     break;
491                 } else {
492                     handles[nhandles++] = (HANDLE) f->fd;
493                 }
494             }
495         }
496     }
497 
498     for (f = fds; f < &fds[nfds]; ++f) {
499         f->revents = 0;
500     }
501 
502     if (timeout == -1) {
503         timeout = INFINITE;
504     }
505 
506     /* Polling for several things? */
507     if (nhandles > 1 || (nhandles > 0 && poll_msgs)) {
508         /* First check if one or several of them are immediately
509          * available
510          */
511         retval = poll_rest(poll_msgs, handles, nhandles, fds, nfds, 0);
512 
513         /* If not, and we have a significant timeout, poll again with
514          * timeout then. Note that this will return indication for only
515          * one event, or only for messages. We ignore timeouts less than
516          * ten milliseconds as they are mostly pointless on Windows, the
517          * MsgWaitForMultipleObjectsEx() call will timeout right away
518          * anyway.
519          *
520          * Modification for QEMU: replaced timeout >= 10 by timeout > 0.
521          */
522         if (retval == 0 && (timeout == INFINITE || timeout > 0)) {
523             retval = poll_rest(poll_msgs, handles, nhandles,
524                                fds, nfds, timeout);
525         }
526     } else {
527         /* Just polling for one thing, so no need to check first if
528          * available immediately
529          */
530         retval = poll_rest(poll_msgs, handles, nhandles, fds, nfds, timeout);
531     }
532 
533     if (retval == -1) {
534         for (f = fds; f < &fds[nfds]; ++f) {
535             f->revents = 0;
536         }
537     }
538 
539     return retval;
540 }
541 #endif
542 
543 int getpagesize(void)
544 {
545     SYSTEM_INFO system_info;
546 
547     GetSystemInfo(&system_info);
548     return system_info.dwPageSize;
549 }
550 
551 void os_mem_prealloc(int fd, char *area, size_t memory, int smp_cpus,
552                      Error **errp)
553 {
554     int i;
555     size_t pagesize = getpagesize();
556 
557     memory = (memory + pagesize - 1) & -pagesize;
558     for (i = 0; i < memory / pagesize; i++) {
559         memset(area + pagesize * i, 0, 1);
560     }
561 }
562 
563 
564 char *qemu_get_pid_name(pid_t pid)
565 {
566     /* XXX Implement me */
567     abort();
568 }
569 
570 
571 pid_t qemu_fork(Error **errp)
572 {
573     errno = ENOSYS;
574     error_setg_errno(errp, errno,
575                      "cannot fork child process");
576     return -1;
577 }
578 
579 
580 #undef connect
581 int qemu_connect_wrap(int sockfd, const struct sockaddr *addr,
582                       socklen_t addrlen)
583 {
584     int ret;
585     ret = connect(sockfd, addr, addrlen);
586     if (ret < 0) {
587         errno = socket_error();
588     }
589     return ret;
590 }
591 
592 
593 #undef listen
594 int qemu_listen_wrap(int sockfd, int backlog)
595 {
596     int ret;
597     ret = listen(sockfd, backlog);
598     if (ret < 0) {
599         errno = socket_error();
600     }
601     return ret;
602 }
603 
604 
605 #undef bind
606 int qemu_bind_wrap(int sockfd, const struct sockaddr *addr,
607                    socklen_t addrlen)
608 {
609     int ret;
610     ret = bind(sockfd, addr, addrlen);
611     if (ret < 0) {
612         errno = socket_error();
613     }
614     return ret;
615 }
616 
617 
618 #undef socket
619 int qemu_socket_wrap(int domain, int type, int protocol)
620 {
621     int ret;
622     ret = socket(domain, type, protocol);
623     if (ret < 0) {
624         errno = socket_error();
625     }
626     return ret;
627 }
628 
629 
630 #undef accept
631 int qemu_accept_wrap(int sockfd, struct sockaddr *addr,
632                      socklen_t *addrlen)
633 {
634     int ret;
635     ret = accept(sockfd, addr, addrlen);
636     if (ret < 0) {
637         errno = socket_error();
638     }
639     return ret;
640 }
641 
642 
643 #undef shutdown
644 int qemu_shutdown_wrap(int sockfd, int how)
645 {
646     int ret;
647     ret = shutdown(sockfd, how);
648     if (ret < 0) {
649         errno = socket_error();
650     }
651     return ret;
652 }
653 
654 
655 #undef ioctlsocket
656 int qemu_ioctlsocket_wrap(int fd, int req, void *val)
657 {
658     int ret;
659     ret = ioctlsocket(fd, req, val);
660     if (ret < 0) {
661         errno = socket_error();
662     }
663     return ret;
664 }
665 
666 
667 #undef closesocket
668 int qemu_closesocket_wrap(int fd)
669 {
670     int ret;
671     ret = closesocket(fd);
672     if (ret < 0) {
673         errno = socket_error();
674     }
675     return ret;
676 }
677 
678 
679 #undef getsockopt
680 int qemu_getsockopt_wrap(int sockfd, int level, int optname,
681                          void *optval, socklen_t *optlen)
682 {
683     int ret;
684     ret = getsockopt(sockfd, level, optname, optval, optlen);
685     if (ret < 0) {
686         errno = socket_error();
687     }
688     return ret;
689 }
690 
691 
692 #undef setsockopt
693 int qemu_setsockopt_wrap(int sockfd, int level, int optname,
694                          const void *optval, socklen_t optlen)
695 {
696     int ret;
697     ret = setsockopt(sockfd, level, optname, optval, optlen);
698     if (ret < 0) {
699         errno = socket_error();
700     }
701     return ret;
702 }
703 
704 
705 #undef getpeername
706 int qemu_getpeername_wrap(int sockfd, struct sockaddr *addr,
707                           socklen_t *addrlen)
708 {
709     int ret;
710     ret = getpeername(sockfd, addr, addrlen);
711     if (ret < 0) {
712         errno = socket_error();
713     }
714     return ret;
715 }
716 
717 
718 #undef getsockname
719 int qemu_getsockname_wrap(int sockfd, struct sockaddr *addr,
720                           socklen_t *addrlen)
721 {
722     int ret;
723     ret = getsockname(sockfd, addr, addrlen);
724     if (ret < 0) {
725         errno = socket_error();
726     }
727     return ret;
728 }
729 
730 
731 #undef send
732 ssize_t qemu_send_wrap(int sockfd, const void *buf, size_t len, int flags)
733 {
734     int ret;
735     ret = send(sockfd, buf, len, flags);
736     if (ret < 0) {
737         errno = socket_error();
738     }
739     return ret;
740 }
741 
742 
743 #undef sendto
744 ssize_t qemu_sendto_wrap(int sockfd, const void *buf, size_t len, int flags,
745                          const struct sockaddr *addr, socklen_t addrlen)
746 {
747     int ret;
748     ret = sendto(sockfd, buf, len, flags, addr, addrlen);
749     if (ret < 0) {
750         errno = socket_error();
751     }
752     return ret;
753 }
754 
755 
756 #undef recv
757 ssize_t qemu_recv_wrap(int sockfd, void *buf, size_t len, int flags)
758 {
759     int ret;
760     ret = recv(sockfd, buf, len, flags);
761     if (ret < 0) {
762         errno = socket_error();
763     }
764     return ret;
765 }
766 
767 
768 #undef recvfrom
769 ssize_t qemu_recvfrom_wrap(int sockfd, void *buf, size_t len, int flags,
770                            struct sockaddr *addr, socklen_t *addrlen)
771 {
772     int ret;
773     ret = recvfrom(sockfd, buf, len, flags, addr, addrlen);
774     if (ret < 0) {
775         errno = socket_error();
776     }
777     return ret;
778 }
779 
780 bool qemu_write_pidfile(const char *filename, Error **errp)
781 {
782     char buffer[128];
783     int len;
784     HANDLE file;
785     OVERLAPPED overlap;
786     BOOL ret;
787     memset(&overlap, 0, sizeof(overlap));
788 
789     file = CreateFile(filename, GENERIC_WRITE, FILE_SHARE_READ, NULL,
790                       OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
791 
792     if (file == INVALID_HANDLE_VALUE) {
793         error_setg(errp, "Failed to create PID file");
794         return false;
795     }
796     len = snprintf(buffer, sizeof(buffer), FMT_pid "\n", (pid_t)getpid());
797     ret = WriteFile(file, (LPCVOID)buffer, (DWORD)len,
798                     NULL, &overlap);
799     CloseHandle(file);
800     if (ret == 0) {
801         error_setg(errp, "Failed to write PID file");
802         return false;
803     }
804     return true;
805 }
806