xref: /openbmc/qemu/util/oslib-win32.c (revision e09484ef)
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 void *qemu_anon_ram_alloc(size_t size, uint64_t *align)
71 {
72     void *ptr;
73 
74     /* FIXME: this is not exactly optimal solution since VirtualAlloc
75        has 64Kb granularity, but at least it guarantees us that the
76        memory is page aligned. */
77     ptr = VirtualAlloc(NULL, size, MEM_COMMIT, PAGE_READWRITE);
78     trace_qemu_anon_ram_alloc(size, ptr);
79     return ptr;
80 }
81 
82 void qemu_vfree(void *ptr)
83 {
84     trace_qemu_vfree(ptr);
85     if (ptr) {
86         VirtualFree(ptr, 0, MEM_RELEASE);
87     }
88 }
89 
90 void qemu_anon_ram_free(void *ptr, size_t size)
91 {
92     trace_qemu_anon_ram_free(ptr, size);
93     if (ptr) {
94         VirtualFree(ptr, 0, MEM_RELEASE);
95     }
96 }
97 
98 #ifndef CONFIG_LOCALTIME_R
99 /* FIXME: add proper locking */
100 struct tm *gmtime_r(const time_t *timep, struct tm *result)
101 {
102     struct tm *p = gmtime(timep);
103     memset(result, 0, sizeof(*result));
104     if (p) {
105         *result = *p;
106         p = result;
107     }
108     return p;
109 }
110 
111 /* FIXME: add proper locking */
112 struct tm *localtime_r(const time_t *timep, struct tm *result)
113 {
114     struct tm *p = localtime(timep);
115     memset(result, 0, sizeof(*result));
116     if (p) {
117         *result = *p;
118         p = result;
119     }
120     return p;
121 }
122 #endif /* CONFIG_LOCALTIME_R */
123 
124 void qemu_set_block(int fd)
125 {
126     unsigned long opt = 0;
127     WSAEventSelect(fd, NULL, 0);
128     ioctlsocket(fd, FIONBIO, &opt);
129 }
130 
131 void qemu_set_nonblock(int fd)
132 {
133     unsigned long opt = 1;
134     ioctlsocket(fd, FIONBIO, &opt);
135     qemu_fd_register(fd);
136 }
137 
138 int socket_set_fast_reuse(int fd)
139 {
140     /* Enabling the reuse of an endpoint that was used by a socket still in
141      * TIME_WAIT state is usually performed by setting SO_REUSEADDR. On Windows
142      * fast reuse is the default and SO_REUSEADDR does strange things. So we
143      * don't have to do anything here. More info can be found at:
144      * http://msdn.microsoft.com/en-us/library/windows/desktop/ms740621.aspx */
145     return 0;
146 }
147 
148 
149 static int socket_error(void)
150 {
151     switch (WSAGetLastError()) {
152     case 0:
153         return 0;
154     case WSAEINTR:
155         return EINTR;
156     case WSAEINVAL:
157         return EINVAL;
158     case WSA_INVALID_HANDLE:
159         return EBADF;
160     case WSA_NOT_ENOUGH_MEMORY:
161         return ENOMEM;
162     case WSA_INVALID_PARAMETER:
163         return EINVAL;
164     case WSAENAMETOOLONG:
165         return ENAMETOOLONG;
166     case WSAENOTEMPTY:
167         return ENOTEMPTY;
168     case WSAEWOULDBLOCK:
169          /* not using EWOULDBLOCK as we don't want code to have
170           * to check both EWOULDBLOCK and EAGAIN */
171         return EAGAIN;
172     case WSAEINPROGRESS:
173         return EINPROGRESS;
174     case WSAEALREADY:
175         return EALREADY;
176     case WSAENOTSOCK:
177         return ENOTSOCK;
178     case WSAEDESTADDRREQ:
179         return EDESTADDRREQ;
180     case WSAEMSGSIZE:
181         return EMSGSIZE;
182     case WSAEPROTOTYPE:
183         return EPROTOTYPE;
184     case WSAENOPROTOOPT:
185         return ENOPROTOOPT;
186     case WSAEPROTONOSUPPORT:
187         return EPROTONOSUPPORT;
188     case WSAEOPNOTSUPP:
189         return EOPNOTSUPP;
190     case WSAEAFNOSUPPORT:
191         return EAFNOSUPPORT;
192     case WSAEADDRINUSE:
193         return EADDRINUSE;
194     case WSAEADDRNOTAVAIL:
195         return EADDRNOTAVAIL;
196     case WSAENETDOWN:
197         return ENETDOWN;
198     case WSAENETUNREACH:
199         return ENETUNREACH;
200     case WSAENETRESET:
201         return ENETRESET;
202     case WSAECONNABORTED:
203         return ECONNABORTED;
204     case WSAECONNRESET:
205         return ECONNRESET;
206     case WSAENOBUFS:
207         return ENOBUFS;
208     case WSAEISCONN:
209         return EISCONN;
210     case WSAENOTCONN:
211         return ENOTCONN;
212     case WSAETIMEDOUT:
213         return ETIMEDOUT;
214     case WSAECONNREFUSED:
215         return ECONNREFUSED;
216     case WSAELOOP:
217         return ELOOP;
218     case WSAEHOSTUNREACH:
219         return EHOSTUNREACH;
220     default:
221         return EIO;
222     }
223 }
224 
225 int inet_aton(const char *cp, struct in_addr *ia)
226 {
227     uint32_t addr = inet_addr(cp);
228     if (addr == 0xffffffff) {
229         return 0;
230     }
231     ia->s_addr = addr;
232     return 1;
233 }
234 
235 void qemu_set_cloexec(int fd)
236 {
237 }
238 
239 /* Offset between 1/1/1601 and 1/1/1970 in 100 nanosec units */
240 #define _W32_FT_OFFSET (116444736000000000ULL)
241 
242 int qemu_gettimeofday(qemu_timeval *tp)
243 {
244   union {
245     unsigned long long ns100; /*time since 1 Jan 1601 in 100ns units */
246     FILETIME ft;
247   }  _now;
248 
249   if(tp) {
250       GetSystemTimeAsFileTime (&_now.ft);
251       tp->tv_usec=(long)((_now.ns100 / 10ULL) % 1000000ULL );
252       tp->tv_sec= (long)((_now.ns100 - _W32_FT_OFFSET) / 10000000ULL);
253   }
254   /* Always return 0 as per Open Group Base Specifications Issue 6.
255      Do not set errno on error.  */
256   return 0;
257 }
258 
259 int qemu_get_thread_id(void)
260 {
261     return GetCurrentThreadId();
262 }
263 
264 char *
265 qemu_get_local_state_pathname(const char *relative_pathname)
266 {
267     HRESULT result;
268     char base_path[MAX_PATH+1] = "";
269 
270     result = SHGetFolderPath(NULL, CSIDL_COMMON_APPDATA, NULL,
271                              /* SHGFP_TYPE_CURRENT */ 0, base_path);
272     if (result != S_OK) {
273         /* misconfigured environment */
274         g_critical("CSIDL_COMMON_APPDATA unavailable: %ld", (long)result);
275         abort();
276     }
277     return g_strdup_printf("%s" G_DIR_SEPARATOR_S "%s", base_path,
278                            relative_pathname);
279 }
280 
281 void qemu_set_tty_echo(int fd, bool echo)
282 {
283     HANDLE handle = (HANDLE)_get_osfhandle(fd);
284     DWORD dwMode = 0;
285 
286     if (handle == INVALID_HANDLE_VALUE) {
287         return;
288     }
289 
290     GetConsoleMode(handle, &dwMode);
291 
292     if (echo) {
293         SetConsoleMode(handle, dwMode | ENABLE_ECHO_INPUT | ENABLE_LINE_INPUT);
294     } else {
295         SetConsoleMode(handle,
296                        dwMode & ~(ENABLE_ECHO_INPUT | ENABLE_LINE_INPUT));
297     }
298 }
299 
300 static char exec_dir[PATH_MAX];
301 
302 void qemu_init_exec_dir(const char *argv0)
303 {
304 
305     char *p;
306     char buf[MAX_PATH];
307     DWORD len;
308 
309     len = GetModuleFileName(NULL, buf, sizeof(buf) - 1);
310     if (len == 0) {
311         return;
312     }
313 
314     buf[len] = 0;
315     p = buf + len - 1;
316     while (p != buf && *p != '\\') {
317         p--;
318     }
319     *p = 0;
320     if (access(buf, R_OK) == 0) {
321         pstrcpy(exec_dir, sizeof(exec_dir), buf);
322     }
323 }
324 
325 char *qemu_get_exec_dir(void)
326 {
327     return g_strdup(exec_dir);
328 }
329 
330 /*
331  * The original implementation of g_poll from glib has a problem on Windows
332  * when using timeouts < 10 ms.
333  *
334  * Whenever g_poll is called with timeout < 10 ms, it does a quick poll instead
335  * of wait. This causes significant performance degradation of QEMU.
336  *
337  * The following code is a copy of the original code from glib/gpoll.c
338  * (glib commit 20f4d1820b8d4d0fc4447188e33efffd6d4a88d8 from 2014-02-19).
339  * Some debug code was removed and the code was reformatted.
340  * All other code modifications are marked with 'QEMU'.
341  */
342 
343 /*
344  * gpoll.c: poll(2) abstraction
345  * Copyright 1998 Owen Taylor
346  * Copyright 2008 Red Hat, Inc.
347  *
348  * This library is free software; you can redistribute it and/or
349  * modify it under the terms of the GNU Lesser General Public
350  * License as published by the Free Software Foundation; either
351  * version 2 of the License, or (at your option) any later version.
352  *
353  * This library is distributed in the hope that it will be useful,
354  * but WITHOUT ANY WARRANTY; without even the implied warranty of
355  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
356  * Lesser General Public License for more details.
357  *
358  * You should have received a copy of the GNU Lesser General Public
359  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
360  */
361 
362 static int poll_rest(gboolean poll_msgs, HANDLE *handles, gint nhandles,
363                      GPollFD *fds, guint nfds, gint timeout)
364 {
365     DWORD ready;
366     GPollFD *f;
367     int recursed_result;
368 
369     if (poll_msgs) {
370         /* Wait for either messages or handles
371          * -> Use MsgWaitForMultipleObjectsEx
372          */
373         ready = MsgWaitForMultipleObjectsEx(nhandles, handles, timeout,
374                                             QS_ALLINPUT, MWMO_ALERTABLE);
375 
376         if (ready == WAIT_FAILED) {
377             gchar *emsg = g_win32_error_message(GetLastError());
378             g_warning("MsgWaitForMultipleObjectsEx failed: %s", emsg);
379             g_free(emsg);
380         }
381     } else if (nhandles == 0) {
382         /* No handles to wait for, just the timeout */
383         if (timeout == INFINITE) {
384             ready = WAIT_FAILED;
385         } else {
386             SleepEx(timeout, TRUE);
387             ready = WAIT_TIMEOUT;
388         }
389     } else {
390         /* Wait for just handles
391          * -> Use WaitForMultipleObjectsEx
392          */
393         ready =
394             WaitForMultipleObjectsEx(nhandles, handles, FALSE, timeout, TRUE);
395         if (ready == WAIT_FAILED) {
396             gchar *emsg = g_win32_error_message(GetLastError());
397             g_warning("WaitForMultipleObjectsEx failed: %s", emsg);
398             g_free(emsg);
399         }
400     }
401 
402     if (ready == WAIT_FAILED) {
403         return -1;
404     } else if (ready == WAIT_TIMEOUT || ready == WAIT_IO_COMPLETION) {
405         return 0;
406     } else if (poll_msgs && ready == WAIT_OBJECT_0 + nhandles) {
407         for (f = fds; f < &fds[nfds]; ++f) {
408             if (f->fd == G_WIN32_MSG_HANDLE && f->events & G_IO_IN) {
409                 f->revents |= G_IO_IN;
410             }
411         }
412 
413         /* If we have a timeout, or no handles to poll, be satisfied
414          * with just noticing we have messages waiting.
415          */
416         if (timeout != 0 || nhandles == 0) {
417             return 1;
418         }
419 
420         /* If no timeout and handles to poll, recurse to poll them,
421          * too.
422          */
423         recursed_result = poll_rest(FALSE, handles, nhandles, fds, nfds, 0);
424         return (recursed_result == -1) ? -1 : 1 + recursed_result;
425     } else if (/* QEMU: removed the following unneeded statement which causes
426                 * a compiler warning: ready >= WAIT_OBJECT_0 && */
427                ready < WAIT_OBJECT_0 + nhandles) {
428         for (f = fds; f < &fds[nfds]; ++f) {
429             if ((HANDLE) f->fd == handles[ready - WAIT_OBJECT_0]) {
430                 f->revents = f->events;
431             }
432         }
433 
434         /* If no timeout and polling several handles, recurse to poll
435          * the rest of them.
436          */
437         if (timeout == 0 && nhandles > 1) {
438             /* Remove the handle that fired */
439             int i;
440             if (ready < nhandles - 1) {
441                 for (i = ready - WAIT_OBJECT_0 + 1; i < nhandles; i++) {
442                     handles[i-1] = handles[i];
443                 }
444             }
445             nhandles--;
446             recursed_result = poll_rest(FALSE, handles, nhandles, fds, nfds, 0);
447             return (recursed_result == -1) ? -1 : 1 + recursed_result;
448         }
449         return 1;
450     }
451 
452     return 0;
453 }
454 
455 gint g_poll(GPollFD *fds, guint nfds, gint timeout)
456 {
457     HANDLE handles[MAXIMUM_WAIT_OBJECTS];
458     gboolean poll_msgs = FALSE;
459     GPollFD *f;
460     gint nhandles = 0;
461     int retval;
462 
463     for (f = fds; f < &fds[nfds]; ++f) {
464         if (f->fd == G_WIN32_MSG_HANDLE && (f->events & G_IO_IN)) {
465             poll_msgs = TRUE;
466         } else if (f->fd > 0) {
467             /* Don't add the same handle several times into the array, as
468              * docs say that is not allowed, even if it actually does seem
469              * to work.
470              */
471             gint i;
472 
473             for (i = 0; i < nhandles; i++) {
474                 if (handles[i] == (HANDLE) f->fd) {
475                     break;
476                 }
477             }
478 
479             if (i == nhandles) {
480                 if (nhandles == MAXIMUM_WAIT_OBJECTS) {
481                     g_warning("Too many handles to wait for!\n");
482                     break;
483                 } else {
484                     handles[nhandles++] = (HANDLE) f->fd;
485                 }
486             }
487         }
488     }
489 
490     for (f = fds; f < &fds[nfds]; ++f) {
491         f->revents = 0;
492     }
493 
494     if (timeout == -1) {
495         timeout = INFINITE;
496     }
497 
498     /* Polling for several things? */
499     if (nhandles > 1 || (nhandles > 0 && poll_msgs)) {
500         /* First check if one or several of them are immediately
501          * available
502          */
503         retval = poll_rest(poll_msgs, handles, nhandles, fds, nfds, 0);
504 
505         /* If not, and we have a significant timeout, poll again with
506          * timeout then. Note that this will return indication for only
507          * one event, or only for messages. We ignore timeouts less than
508          * ten milliseconds as they are mostly pointless on Windows, the
509          * MsgWaitForMultipleObjectsEx() call will timeout right away
510          * anyway.
511          *
512          * Modification for QEMU: replaced timeout >= 10 by timeout > 0.
513          */
514         if (retval == 0 && (timeout == INFINITE || timeout > 0)) {
515             retval = poll_rest(poll_msgs, handles, nhandles,
516                                fds, nfds, timeout);
517         }
518     } else {
519         /* Just polling for one thing, so no need to check first if
520          * available immediately
521          */
522         retval = poll_rest(poll_msgs, handles, nhandles, fds, nfds, timeout);
523     }
524 
525     if (retval == -1) {
526         for (f = fds; f < &fds[nfds]; ++f) {
527             f->revents = 0;
528         }
529     }
530 
531     return retval;
532 }
533 
534 int getpagesize(void)
535 {
536     SYSTEM_INFO system_info;
537 
538     GetSystemInfo(&system_info);
539     return system_info.dwPageSize;
540 }
541 
542 void os_mem_prealloc(int fd, char *area, size_t memory, Error **errp)
543 {
544     int i;
545     size_t pagesize = getpagesize();
546 
547     memory = (memory + pagesize - 1) & -pagesize;
548     for (i = 0; i < memory / pagesize; i++) {
549         memset(area + pagesize * i, 0, 1);
550     }
551 }
552 
553 
554 /* XXX: put correct support for win32 */
555 int qemu_read_password(char *buf, int buf_size)
556 {
557     int c, i;
558 
559     printf("Password: ");
560     fflush(stdout);
561     i = 0;
562     for (;;) {
563         c = getchar();
564         if (c < 0) {
565             buf[i] = '\0';
566             return -1;
567         } else if (c == '\n') {
568             break;
569         } else if (i < (buf_size - 1)) {
570             buf[i++] = c;
571         }
572     }
573     buf[i] = '\0';
574     return 0;
575 }
576 
577 
578 pid_t qemu_fork(Error **errp)
579 {
580     errno = ENOSYS;
581     error_setg_errno(errp, errno,
582                      "cannot fork child process");
583     return -1;
584 }
585 
586 
587 #undef connect
588 int qemu_connect_wrap(int sockfd, const struct sockaddr *addr,
589                       socklen_t addrlen)
590 {
591     int ret;
592     ret = connect(sockfd, addr, addrlen);
593     if (ret < 0) {
594         errno = socket_error();
595     }
596     return ret;
597 }
598 
599 
600 #undef listen
601 int qemu_listen_wrap(int sockfd, int backlog)
602 {
603     int ret;
604     ret = listen(sockfd, backlog);
605     if (ret < 0) {
606         errno = socket_error();
607     }
608     return ret;
609 }
610 
611 
612 #undef bind
613 int qemu_bind_wrap(int sockfd, const struct sockaddr *addr,
614                    socklen_t addrlen)
615 {
616     int ret;
617     ret = bind(sockfd, addr, addrlen);
618     if (ret < 0) {
619         errno = socket_error();
620     }
621     return ret;
622 }
623 
624 
625 #undef socket
626 int qemu_socket_wrap(int domain, int type, int protocol)
627 {
628     int ret;
629     ret = socket(domain, type, protocol);
630     if (ret < 0) {
631         errno = socket_error();
632     }
633     return ret;
634 }
635 
636 
637 #undef accept
638 int qemu_accept_wrap(int sockfd, struct sockaddr *addr,
639                      socklen_t *addrlen)
640 {
641     int ret;
642     ret = accept(sockfd, addr, addrlen);
643     if (ret < 0) {
644         errno = socket_error();
645     }
646     return ret;
647 }
648 
649 
650 #undef shutdown
651 int qemu_shutdown_wrap(int sockfd, int how)
652 {
653     int ret;
654     ret = shutdown(sockfd, how);
655     if (ret < 0) {
656         errno = socket_error();
657     }
658     return ret;
659 }
660 
661 
662 #undef ioctlsocket
663 int qemu_ioctlsocket_wrap(int fd, int req, void *val)
664 {
665     int ret;
666     ret = ioctlsocket(fd, req, val);
667     if (ret < 0) {
668         errno = socket_error();
669     }
670     return ret;
671 }
672 
673 
674 #undef closesocket
675 int qemu_closesocket_wrap(int fd)
676 {
677     int ret;
678     ret = closesocket(fd);
679     if (ret < 0) {
680         errno = socket_error();
681     }
682     return ret;
683 }
684 
685 
686 #undef getsockopt
687 int qemu_getsockopt_wrap(int sockfd, int level, int optname,
688                          void *optval, socklen_t *optlen)
689 {
690     int ret;
691     ret = getsockopt(sockfd, level, optname, optval, optlen);
692     if (ret < 0) {
693         errno = socket_error();
694     }
695     return ret;
696 }
697 
698 
699 #undef setsockopt
700 int qemu_setsockopt_wrap(int sockfd, int level, int optname,
701                          const void *optval, socklen_t optlen)
702 {
703     int ret;
704     ret = setsockopt(sockfd, level, optname, optval, optlen);
705     if (ret < 0) {
706         errno = socket_error();
707     }
708     return ret;
709 }
710 
711 
712 #undef getpeername
713 int qemu_getpeername_wrap(int sockfd, struct sockaddr *addr,
714                           socklen_t *addrlen)
715 {
716     int ret;
717     ret = getpeername(sockfd, addr, addrlen);
718     if (ret < 0) {
719         errno = socket_error();
720     }
721     return ret;
722 }
723 
724 
725 #undef getsockname
726 int qemu_getsockname_wrap(int sockfd, struct sockaddr *addr,
727                           socklen_t *addrlen)
728 {
729     int ret;
730     ret = getsockname(sockfd, addr, addrlen);
731     if (ret < 0) {
732         errno = socket_error();
733     }
734     return ret;
735 }
736 
737 
738 #undef send
739 ssize_t qemu_send_wrap(int sockfd, const void *buf, size_t len, int flags)
740 {
741     int ret;
742     ret = send(sockfd, buf, len, flags);
743     if (ret < 0) {
744         errno = socket_error();
745     }
746     return ret;
747 }
748 
749 
750 #undef sendto
751 ssize_t qemu_sendto_wrap(int sockfd, const void *buf, size_t len, int flags,
752                          const struct sockaddr *addr, socklen_t addrlen)
753 {
754     int ret;
755     ret = sendto(sockfd, buf, len, flags, addr, addrlen);
756     if (ret < 0) {
757         errno = socket_error();
758     }
759     return ret;
760 }
761 
762 
763 #undef recv
764 ssize_t qemu_recv_wrap(int sockfd, void *buf, size_t len, int flags)
765 {
766     int ret;
767     ret = recv(sockfd, buf, len, flags);
768     if (ret < 0) {
769         errno = socket_error();
770     }
771     return ret;
772 }
773 
774 
775 #undef recvfrom
776 ssize_t qemu_recvfrom_wrap(int sockfd, void *buf, size_t len, int flags,
777                            struct sockaddr *addr, socklen_t *addrlen)
778 {
779     int ret;
780     ret = recvfrom(sockfd, buf, len, flags, addr, addrlen);
781     if (ret < 0) {
782         errno = socket_error();
783     }
784     return ret;
785 }
786