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Commit | Line | Data |
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ea88812f FB |
1 | /* |
2 | * QEMU low level functions | |
5fafdf24 | 3 | * |
ea88812f | 4 | * Copyright (c) 2003 Fabrice Bellard |
5fafdf24 | 5 | * |
ea88812f FB |
6 | * Permission is hereby granted, free of charge, to any person obtaining a copy |
7 | * of this software and associated documentation files (the "Software"), to deal | |
8 | * in the Software without restriction, including without limitation the rights | |
9 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
10 | * copies of the Software, and to permit persons to whom the Software is | |
11 | * furnished to do so, subject to the following conditions: | |
12 | * | |
13 | * The above copyright notice and this permission notice shall be included in | |
14 | * all copies or substantial portions of the Software. | |
15 | * | |
16 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
17 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
18 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL | |
19 | * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
20 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
21 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN | |
22 | * THE SOFTWARE. | |
23 | */ | |
aafd7584 | 24 | #include "qemu/osdep.h" |
ebb3d49c | 25 | #include "qapi/error.h" |
f348b6d1 | 26 | #include "qemu/cutils.h" |
1de7afc9 | 27 | #include "qemu/sockets.h" |
d49b6836 | 28 | #include "qemu/error-report.h" |
b85ea5fa | 29 | #include "qemu/madvise.h" |
f2241d16 | 30 | #include "qemu/mprotect.h" |
15e09912 | 31 | #include "qemu/hw-version.h" |
83c9089e | 32 | #include "monitor/monitor.h" |
03ff3ca3 | 33 | |
d494352c | 34 | static const char *hw_version = QEMU_HW_VERSION; |
93bfef4c | 35 | |
128aa589 PB |
36 | int socket_set_cork(int fd, int v) |
37 | { | |
38 | #if defined(SOL_TCP) && defined(TCP_CORK) | |
e7b79428 | 39 | return setsockopt(fd, SOL_TCP, TCP_CORK, &v, sizeof(v)); |
128aa589 PB |
40 | #else |
41 | return 0; | |
42 | #endif | |
43 | } | |
44 | ||
bf1c852a MK |
45 | int socket_set_nodelay(int fd) |
46 | { | |
47 | int v = 1; | |
e7b79428 | 48 | return setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &v, sizeof(v)); |
bf1c852a MK |
49 | } |
50 | ||
e78815a5 AF |
51 | int qemu_madvise(void *addr, size_t len, int advice) |
52 | { | |
53 | if (advice == QEMU_MADV_INVALID) { | |
54 | errno = EINVAL; | |
55 | return -1; | |
56 | } | |
57 | #if defined(CONFIG_MADVISE) | |
58 | return madvise(addr, len, advice); | |
59 | #elif defined(CONFIG_POSIX_MADVISE) | |
bfb8c79f MP |
60 | int rc = posix_madvise(addr, len, advice); |
61 | if (rc) { | |
62 | errno = rc; | |
63 | return -1; | |
64 | } | |
65 | return 0; | |
e78815a5 | 66 | #else |
210b7b2b | 67 | errno = ENOSYS; |
e78815a5 AF |
68 | return -1; |
69 | #endif | |
70 | } | |
71 | ||
5fa64b31 EC |
72 | static int qemu_mprotect__osdep(void *addr, size_t size, int prot) |
73 | { | |
8e3b0cbb MAL |
74 | g_assert(!((uintptr_t)addr & ~qemu_real_host_page_mask())); |
75 | g_assert(!(size & ~qemu_real_host_page_mask())); | |
5fa64b31 EC |
76 | |
77 | #ifdef _WIN32 | |
78 | DWORD old_protect; | |
79 | ||
80 | if (!VirtualProtect(addr, size, prot, &old_protect)) { | |
cf0c76cd PMD |
81 | g_autofree gchar *emsg = g_win32_error_message(GetLastError()); |
82 | error_report("%s: VirtualProtect failed: %s", __func__, emsg); | |
5fa64b31 EC |
83 | return -1; |
84 | } | |
85 | return 0; | |
86 | #else | |
87 | if (mprotect(addr, size, prot)) { | |
88 | error_report("%s: mprotect failed: %s", __func__, strerror(errno)); | |
89 | return -1; | |
90 | } | |
91 | return 0; | |
92 | #endif | |
93 | } | |
94 | ||
d7107fc0 RH |
95 | int qemu_mprotect_rw(void *addr, size_t size) |
96 | { | |
97 | #ifdef _WIN32 | |
98 | return qemu_mprotect__osdep(addr, size, PAGE_READWRITE); | |
99 | #else | |
100 | return qemu_mprotect__osdep(addr, size, PROT_READ | PROT_WRITE); | |
101 | #endif | |
102 | } | |
103 | ||
5fa64b31 EC |
104 | int qemu_mprotect_rwx(void *addr, size_t size) |
105 | { | |
106 | #ifdef _WIN32 | |
107 | return qemu_mprotect__osdep(addr, size, PAGE_EXECUTE_READWRITE); | |
108 | #else | |
109 | return qemu_mprotect__osdep(addr, size, PROT_READ | PROT_WRITE | PROT_EXEC); | |
110 | #endif | |
111 | } | |
112 | ||
113 | int qemu_mprotect_none(void *addr, size_t size) | |
114 | { | |
115 | #ifdef _WIN32 | |
116 | return qemu_mprotect__osdep(addr, size, PAGE_NOACCESS); | |
117 | #else | |
118 | return qemu_mprotect__osdep(addr, size, PROT_NONE); | |
119 | #endif | |
120 | } | |
121 | ||
adb696f3 | 122 | #ifndef _WIN32 |
ca749954 FZ |
123 | |
124 | static int fcntl_op_setlk = -1; | |
125 | static int fcntl_op_getlk = -1; | |
126 | ||
adb696f3 CB |
127 | /* |
128 | * Dups an fd and sets the flags | |
129 | */ | |
60efffa4 | 130 | int qemu_dup_flags(int fd, int flags) |
adb696f3 CB |
131 | { |
132 | int ret; | |
133 | int serrno; | |
134 | int dup_flags; | |
adb696f3 | 135 | |
761d1ddf | 136 | ret = qemu_dup(fd); |
adb696f3 CB |
137 | if (ret == -1) { |
138 | goto fail; | |
139 | } | |
140 | ||
141 | dup_flags = fcntl(ret, F_GETFL); | |
142 | if (dup_flags == -1) { | |
143 | goto fail; | |
144 | } | |
145 | ||
146 | if ((flags & O_SYNC) != (dup_flags & O_SYNC)) { | |
147 | errno = EINVAL; | |
148 | goto fail; | |
149 | } | |
150 | ||
151 | /* Set/unset flags that we can with fcntl */ | |
3b6eda2f | 152 | if (fcntl(ret, F_SETFL, flags) == -1) { |
adb696f3 CB |
153 | goto fail; |
154 | } | |
155 | ||
156 | /* Truncate the file in the cases that open() would truncate it */ | |
157 | if (flags & O_TRUNC || | |
158 | ((flags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))) { | |
159 | if (ftruncate(ret, 0) == -1) { | |
160 | goto fail; | |
161 | } | |
162 | } | |
163 | ||
164 | return ret; | |
165 | ||
166 | fail: | |
167 | serrno = errno; | |
168 | if (ret != -1) { | |
169 | close(ret); | |
170 | } | |
171 | errno = serrno; | |
172 | return -1; | |
173 | } | |
0100fbbe | 174 | |
761d1ddf FZ |
175 | int qemu_dup(int fd) |
176 | { | |
177 | int ret; | |
178 | #ifdef F_DUPFD_CLOEXEC | |
179 | ret = fcntl(fd, F_DUPFD_CLOEXEC, 0); | |
180 | #else | |
181 | ret = dup(fd); | |
182 | if (ret != -1) { | |
183 | qemu_set_cloexec(ret); | |
184 | } | |
185 | #endif | |
186 | return ret; | |
187 | } | |
188 | ||
0100fbbe PB |
189 | static int qemu_parse_fdset(const char *param) |
190 | { | |
191 | return qemu_parse_fd(param); | |
192 | } | |
13461fdb | 193 | |
ca749954 FZ |
194 | static void qemu_probe_lock_ops(void) |
195 | { | |
196 | if (fcntl_op_setlk == -1) { | |
197 | #ifdef F_OFD_SETLK | |
198 | int fd; | |
199 | int ret; | |
200 | struct flock fl = { | |
201 | .l_whence = SEEK_SET, | |
202 | .l_start = 0, | |
203 | .l_len = 0, | |
204 | .l_type = F_WRLCK, | |
205 | }; | |
206 | ||
207 | fd = open("/dev/null", O_RDWR); | |
208 | if (fd < 0) { | |
209 | fprintf(stderr, | |
210 | "Failed to open /dev/null for OFD lock probing: %s\n", | |
211 | strerror(errno)); | |
212 | fcntl_op_setlk = F_SETLK; | |
213 | fcntl_op_getlk = F_GETLK; | |
214 | return; | |
215 | } | |
216 | ret = fcntl(fd, F_OFD_GETLK, &fl); | |
217 | close(fd); | |
218 | if (!ret) { | |
219 | fcntl_op_setlk = F_OFD_SETLK; | |
220 | fcntl_op_getlk = F_OFD_GETLK; | |
221 | } else { | |
222 | fcntl_op_setlk = F_SETLK; | |
223 | fcntl_op_getlk = F_GETLK; | |
224 | } | |
225 | #else | |
226 | fcntl_op_setlk = F_SETLK; | |
227 | fcntl_op_getlk = F_GETLK; | |
228 | #endif | |
229 | } | |
230 | } | |
231 | ||
232 | bool qemu_has_ofd_lock(void) | |
233 | { | |
234 | qemu_probe_lock_ops(); | |
235 | #ifdef F_OFD_SETLK | |
236 | return fcntl_op_setlk == F_OFD_SETLK; | |
237 | #else | |
238 | return false; | |
239 | #endif | |
240 | } | |
241 | ||
13461fdb FZ |
242 | static int qemu_lock_fcntl(int fd, int64_t start, int64_t len, int fl_type) |
243 | { | |
13461fdb FZ |
244 | int ret; |
245 | struct flock fl = { | |
246 | .l_whence = SEEK_SET, | |
247 | .l_start = start, | |
248 | .l_len = len, | |
249 | .l_type = fl_type, | |
250 | }; | |
ca749954 | 251 | qemu_probe_lock_ops(); |
37b0b24e | 252 | ret = RETRY_ON_EINTR(fcntl(fd, fcntl_op_setlk, &fl)); |
13461fdb | 253 | return ret == -1 ? -errno : 0; |
13461fdb FZ |
254 | } |
255 | ||
256 | int qemu_lock_fd(int fd, int64_t start, int64_t len, bool exclusive) | |
257 | { | |
258 | return qemu_lock_fcntl(fd, start, len, exclusive ? F_WRLCK : F_RDLCK); | |
259 | } | |
260 | ||
261 | int qemu_unlock_fd(int fd, int64_t start, int64_t len) | |
262 | { | |
263 | return qemu_lock_fcntl(fd, start, len, F_UNLCK); | |
264 | } | |
265 | ||
266 | int qemu_lock_fd_test(int fd, int64_t start, int64_t len, bool exclusive) | |
267 | { | |
13461fdb FZ |
268 | int ret; |
269 | struct flock fl = { | |
270 | .l_whence = SEEK_SET, | |
271 | .l_start = start, | |
272 | .l_len = len, | |
273 | .l_type = exclusive ? F_WRLCK : F_RDLCK, | |
274 | }; | |
ca749954 FZ |
275 | qemu_probe_lock_ops(); |
276 | ret = fcntl(fd, fcntl_op_getlk, &fl); | |
13461fdb FZ |
277 | if (ret == -1) { |
278 | return -errno; | |
279 | } else { | |
280 | return fl.l_type == F_UNLCK ? 0 : -EAGAIN; | |
281 | } | |
13461fdb | 282 | } |
adb696f3 | 283 | #endif |
03ff3ca3 | 284 | |
b43b61d5 FR |
285 | bool qemu_has_direct_io(void) |
286 | { | |
287 | #ifdef O_DIRECT | |
288 | return true; | |
289 | #else | |
290 | return false; | |
291 | #endif | |
292 | } | |
293 | ||
c2069ff6 DB |
294 | static int qemu_open_cloexec(const char *name, int flags, mode_t mode) |
295 | { | |
296 | int ret; | |
297 | #ifdef O_CLOEXEC | |
298 | ret = open(name, flags | O_CLOEXEC, mode); | |
299 | #else | |
300 | ret = open(name, flags, mode); | |
301 | if (ret >= 0) { | |
302 | qemu_set_cloexec(ret); | |
303 | } | |
304 | #endif | |
305 | return ret; | |
306 | } | |
307 | ||
40ff6d7e KW |
308 | /* |
309 | * Opens a file with FD_CLOEXEC set | |
310 | */ | |
bf93d2ad | 311 | static int |
ebb3d49c | 312 | qemu_open_internal(const char *name, int flags, mode_t mode, Error **errp) |
40ff6d7e KW |
313 | { |
314 | int ret; | |
40ff6d7e | 315 | |
adb696f3 CB |
316 | #ifndef _WIN32 |
317 | const char *fdset_id_str; | |
318 | ||
319 | /* Attempt dup of fd from fd set */ | |
320 | if (strstart(name, "/dev/fdset/", &fdset_id_str)) { | |
321 | int64_t fdset_id; | |
adb696f3 CB |
322 | |
323 | fdset_id = qemu_parse_fdset(fdset_id_str); | |
324 | if (fdset_id == -1) { | |
ebb3d49c | 325 | error_setg(errp, "Could not parse fdset %s", name); |
adb696f3 CB |
326 | errno = EINVAL; |
327 | return -1; | |
328 | } | |
329 | ||
960f29b3 | 330 | return monitor_fdset_dup_fd_add(fdset_id, flags, errp); |
adb696f3 CB |
331 | } |
332 | #endif | |
333 | ||
bf93d2ad DB |
334 | ret = qemu_open_cloexec(name, flags, mode); |
335 | ||
ebb3d49c DB |
336 | if (ret == -1) { |
337 | const char *action = flags & O_CREAT ? "create" : "open"; | |
661b3e81 DB |
338 | #ifdef O_DIRECT |
339 | /* Give more helpful error message for O_DIRECT */ | |
340 | if (errno == EINVAL && (flags & O_DIRECT)) { | |
341 | ret = open(name, flags & ~O_DIRECT, mode); | |
342 | if (ret != -1) { | |
343 | close(ret); | |
344 | error_setg(errp, "Could not %s '%s': " | |
345 | "filesystem does not support O_DIRECT", | |
346 | action, name); | |
347 | errno = EINVAL; /* restore first open()'s errno */ | |
348 | return -1; | |
349 | } | |
350 | } | |
351 | #endif /* O_DIRECT */ | |
ebb3d49c DB |
352 | error_setg_errno(errp, errno, "Could not %s '%s'", |
353 | action, name); | |
354 | } | |
355 | ||
bf93d2ad DB |
356 | return ret; |
357 | } | |
358 | ||
40ff6d7e | 359 | |
c490af57 DB |
360 | int qemu_open(const char *name, int flags, Error **errp) |
361 | { | |
362 | assert(!(flags & O_CREAT)); | |
363 | ||
364 | return qemu_open_internal(name, flags, 0, errp); | |
365 | } | |
366 | ||
367 | ||
368 | int qemu_create(const char *name, int flags, mode_t mode, Error **errp) | |
369 | { | |
370 | assert(!(flags & O_CREAT)); | |
371 | ||
372 | return qemu_open_internal(name, flags | O_CREAT, mode, errp); | |
373 | } | |
374 | ||
375 | ||
bf93d2ad DB |
376 | int qemu_open_old(const char *name, int flags, ...) |
377 | { | |
378 | va_list ap; | |
379 | mode_t mode = 0; | |
380 | int ret; | |
381 | ||
382 | va_start(ap, flags); | |
383 | if (flags & O_CREAT) { | |
40ff6d7e | 384 | mode = va_arg(ap, int); |
40ff6d7e | 385 | } |
bf93d2ad | 386 | va_end(ap); |
40ff6d7e | 387 | |
ebb3d49c | 388 | ret = qemu_open_internal(name, flags, mode, NULL); |
40ff6d7e | 389 | |
a5813077 SH |
390 | #ifdef O_DIRECT |
391 | if (ret == -1 && errno == EINVAL && (flags & O_DIRECT)) { | |
392 | error_report("file system may not support O_DIRECT"); | |
393 | errno = EINVAL; /* in case it was clobbered */ | |
394 | } | |
395 | #endif /* O_DIRECT */ | |
396 | ||
40ff6d7e KW |
397 | return ret; |
398 | } | |
399 | ||
2e1e79da CB |
400 | int qemu_close(int fd) |
401 | { | |
adb696f3 | 402 | /* Close fd that was dup'd from an fdset */ |
1cd93fb0 | 403 | monitor_fdset_dup_fd_remove(fd); |
2e1e79da CB |
404 | return close(fd); |
405 | } | |
406 | ||
ee13240e MAL |
407 | /* |
408 | * Delete a file from the filesystem, unless the filename is /dev/fdset/... | |
409 | * | |
410 | * Returns: On success, zero is returned. On error, -1 is returned, | |
411 | * and errno is set appropriately. | |
412 | */ | |
413 | int qemu_unlink(const char *name) | |
414 | { | |
415 | if (g_str_has_prefix(name, "/dev/fdset/")) { | |
416 | return 0; | |
417 | } | |
418 | ||
419 | return unlink(name); | |
420 | } | |
421 | ||
7b5f699d KS |
422 | /* |
423 | * A variant of write(2) which handles partial write. | |
424 | * | |
425 | * Return the number of bytes transferred. | |
426 | * Set errno if fewer than `count' bytes are written. | |
1298cb68 JQ |
427 | * |
428 | * This function don't work with non-blocking fd's. | |
8cc360b9 | 429 | * Any of the possibilities with non-blocking fd's is bad: |
1298cb68 JQ |
430 | * - return a short write (then name is wrong) |
431 | * - busy wait adding (errno == EAGAIN) to the loop | |
7b5f699d KS |
432 | */ |
433 | ssize_t qemu_write_full(int fd, const void *buf, size_t count) | |
434 | { | |
435 | ssize_t ret = 0; | |
436 | ssize_t total = 0; | |
437 | ||
438 | while (count) { | |
439 | ret = write(fd, buf, count); | |
440 | if (ret < 0) { | |
441 | if (errno == EINTR) | |
442 | continue; | |
443 | break; | |
444 | } | |
445 | ||
446 | count -= ret; | |
447 | buf += ret; | |
448 | total += ret; | |
449 | } | |
450 | ||
451 | return total; | |
452 | } | |
453 | ||
40ff6d7e KW |
454 | /* |
455 | * Opens a socket with FD_CLOEXEC set | |
456 | */ | |
457 | int qemu_socket(int domain, int type, int protocol) | |
458 | { | |
459 | int ret; | |
460 | ||
461 | #ifdef SOCK_CLOEXEC | |
462 | ret = socket(domain, type | SOCK_CLOEXEC, protocol); | |
3a03bfa5 AP |
463 | if (ret != -1 || errno != EINVAL) { |
464 | return ret; | |
465 | } | |
466 | #endif | |
40ff6d7e KW |
467 | ret = socket(domain, type, protocol); |
468 | if (ret >= 0) { | |
469 | qemu_set_cloexec(ret); | |
470 | } | |
40ff6d7e KW |
471 | |
472 | return ret; | |
473 | } | |
474 | ||
475 | /* | |
476 | * Accept a connection and set FD_CLOEXEC | |
477 | */ | |
478 | int qemu_accept(int s, struct sockaddr *addr, socklen_t *addrlen) | |
479 | { | |
480 | int ret; | |
481 | ||
482 | #ifdef CONFIG_ACCEPT4 | |
483 | ret = accept4(s, addr, addrlen, SOCK_CLOEXEC); | |
347ed55c | 484 | if (ret != -1 || errno != ENOSYS) { |
3a03bfa5 AP |
485 | return ret; |
486 | } | |
487 | #endif | |
40ff6d7e KW |
488 | ret = accept(s, addr, addrlen); |
489 | if (ret >= 0) { | |
490 | qemu_set_cloexec(ret); | |
491 | } | |
40ff6d7e KW |
492 | |
493 | return ret; | |
494 | } | |
993295fe | 495 | |
84c662d2 XC |
496 | ssize_t qemu_send_full(int s, const void *buf, size_t count) |
497 | { | |
498 | ssize_t ret = 0; | |
499 | ssize_t total = 0; | |
500 | ||
501 | while (count) { | |
502 | ret = send(s, buf, count, 0); | |
503 | if (ret < 0) { | |
504 | if (errno == EINTR) { | |
505 | continue; | |
506 | } | |
507 | break; | |
508 | } | |
509 | ||
510 | count -= ret; | |
511 | buf += ret; | |
512 | total += ret; | |
513 | } | |
514 | ||
515 | return total; | |
516 | } | |
517 | ||
35c2c8dc | 518 | void qemu_set_hw_version(const char *version) |
93bfef4c | 519 | { |
35c2c8dc | 520 | hw_version = version; |
93bfef4c CV |
521 | } |
522 | ||
35c2c8dc | 523 | const char *qemu_hw_version(void) |
93bfef4c | 524 | { |
35c2c8dc | 525 | return hw_version; |
93bfef4c | 526 | } |
0f66998f | 527 | |
d3bf825e MAL |
528 | #ifdef _WIN32 |
529 | static void socket_cleanup(void) | |
530 | { | |
531 | WSACleanup(); | |
532 | } | |
533 | #endif | |
534 | ||
535 | int socket_init(void) | |
536 | { | |
537 | #ifdef _WIN32 | |
538 | WSADATA Data; | |
539 | int ret, err; | |
540 | ||
541 | ret = WSAStartup(MAKEWORD(2, 2), &Data); | |
542 | if (ret != 0) { | |
543 | err = WSAGetLastError(); | |
544 | fprintf(stderr, "WSAStartup: %d\n", err); | |
545 | return -1; | |
546 | } | |
547 | atexit(socket_cleanup); | |
548 | #endif | |
549 | return 0; | |
550 | } | |
9adea5f7 | 551 | |
ae2990c2 | 552 | |
9adea5f7 | 553 | #ifndef CONFIG_IOVEC |
9adea5f7 PB |
554 | static ssize_t |
555 | readv_writev(int fd, const struct iovec *iov, int iov_cnt, bool do_write) | |
556 | { | |
557 | unsigned i = 0; | |
558 | ssize_t ret = 0; | |
c1f79809 | 559 | ssize_t off = 0; |
9adea5f7 PB |
560 | while (i < iov_cnt) { |
561 | ssize_t r = do_write | |
c1f79809 MAL |
562 | ? write(fd, iov[i].iov_base + off, iov[i].iov_len - off) |
563 | : read(fd, iov[i].iov_base + off, iov[i].iov_len - off); | |
9adea5f7 PB |
564 | if (r > 0) { |
565 | ret += r; | |
c1f79809 MAL |
566 | off += r; |
567 | if (off < iov[i].iov_len) { | |
568 | continue; | |
569 | } | |
9adea5f7 PB |
570 | } else if (!r) { |
571 | break; | |
572 | } else if (errno == EINTR) { | |
573 | continue; | |
574 | } else { | |
575 | /* else it is some "other" error, | |
576 | * only return if there was no data processed. */ | |
577 | if (ret == 0) { | |
578 | ret = -1; | |
579 | } | |
580 | break; | |
581 | } | |
c1f79809 | 582 | off = 0; |
9adea5f7 PB |
583 | i++; |
584 | } | |
585 | return ret; | |
586 | } | |
587 | ||
588 | ssize_t | |
589 | readv(int fd, const struct iovec *iov, int iov_cnt) | |
590 | { | |
591 | return readv_writev(fd, iov, iov_cnt, false); | |
592 | } | |
593 | ||
594 | ssize_t | |
595 | writev(int fd, const struct iovec *iov, int iov_cnt) | |
596 | { | |
597 | return readv_writev(fd, iov, iov_cnt, true); | |
598 | } | |
599 | #endif | |
282468c7 MAL |
600 | |
601 | /* | |
602 | * Make sure data goes on disk, but if possible do not bother to | |
603 | * write out the inode just for timestamp updates. | |
604 | * | |
605 | * Unfortunately even in 2009 many operating systems do not support | |
606 | * fdatasync and have to fall back to fsync. | |
607 | */ | |
608 | int qemu_fdatasync(int fd) | |
609 | { | |
610 | #ifdef CONFIG_FDATASYNC | |
611 | return fdatasync(fd); | |
612 | #else | |
613 | return fsync(fd); | |
614 | #endif | |
615 | } |