util: introduce qemu_open and qemu_create with error reporting
[qemu.git] / util / osdep.c
1 /*
2 * QEMU low level functions
3 *
4 * Copyright (c) 2003 Fabrice Bellard
5 *
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 */
24 #include "qemu/osdep.h"
25 #include "qapi/error.h"
26
27 /* Needed early for CONFIG_BSD etc. */
28
29 #ifdef CONFIG_SOLARIS
30 #include <sys/statvfs.h>
31 /* See MySQL bug #7156 (http://bugs.mysql.com/bug.php?id=7156) for
32 discussion about Solaris header problems */
33 extern int madvise(char *, size_t, int);
34 #endif
35
36 #include "qemu-common.h"
37 #include "qemu/cutils.h"
38 #include "qemu/sockets.h"
39 #include "qemu/error-report.h"
40 #include "monitor/monitor.h"
41
42 static bool fips_enabled = false;
43
44 static const char *hw_version = QEMU_HW_VERSION;
45
46 int socket_set_cork(int fd, int v)
47 {
48 #if defined(SOL_TCP) && defined(TCP_CORK)
49 return qemu_setsockopt(fd, SOL_TCP, TCP_CORK, &v, sizeof(v));
50 #else
51 return 0;
52 #endif
53 }
54
55 int socket_set_nodelay(int fd)
56 {
57 int v = 1;
58 return qemu_setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &v, sizeof(v));
59 }
60
61 int qemu_madvise(void *addr, size_t len, int advice)
62 {
63 if (advice == QEMU_MADV_INVALID) {
64 errno = EINVAL;
65 return -1;
66 }
67 #if defined(CONFIG_MADVISE)
68 return madvise(addr, len, advice);
69 #elif defined(CONFIG_POSIX_MADVISE)
70 return posix_madvise(addr, len, advice);
71 #else
72 errno = EINVAL;
73 return -1;
74 #endif
75 }
76
77 static int qemu_mprotect__osdep(void *addr, size_t size, int prot)
78 {
79 g_assert(!((uintptr_t)addr & ~qemu_real_host_page_mask));
80 g_assert(!(size & ~qemu_real_host_page_mask));
81
82 #ifdef _WIN32
83 DWORD old_protect;
84
85 if (!VirtualProtect(addr, size, prot, &old_protect)) {
86 g_autofree gchar *emsg = g_win32_error_message(GetLastError());
87 error_report("%s: VirtualProtect failed: %s", __func__, emsg);
88 return -1;
89 }
90 return 0;
91 #else
92 if (mprotect(addr, size, prot)) {
93 error_report("%s: mprotect failed: %s", __func__, strerror(errno));
94 return -1;
95 }
96 return 0;
97 #endif
98 }
99
100 int qemu_mprotect_rwx(void *addr, size_t size)
101 {
102 #ifdef _WIN32
103 return qemu_mprotect__osdep(addr, size, PAGE_EXECUTE_READWRITE);
104 #else
105 return qemu_mprotect__osdep(addr, size, PROT_READ | PROT_WRITE | PROT_EXEC);
106 #endif
107 }
108
109 int qemu_mprotect_none(void *addr, size_t size)
110 {
111 #ifdef _WIN32
112 return qemu_mprotect__osdep(addr, size, PAGE_NOACCESS);
113 #else
114 return qemu_mprotect__osdep(addr, size, PROT_NONE);
115 #endif
116 }
117
118 #ifndef _WIN32
119
120 static int fcntl_op_setlk = -1;
121 static int fcntl_op_getlk = -1;
122
123 /*
124 * Dups an fd and sets the flags
125 */
126 int qemu_dup_flags(int fd, int flags)
127 {
128 int ret;
129 int serrno;
130 int dup_flags;
131
132 ret = qemu_dup(fd);
133 if (ret == -1) {
134 goto fail;
135 }
136
137 dup_flags = fcntl(ret, F_GETFL);
138 if (dup_flags == -1) {
139 goto fail;
140 }
141
142 if ((flags & O_SYNC) != (dup_flags & O_SYNC)) {
143 errno = EINVAL;
144 goto fail;
145 }
146
147 /* Set/unset flags that we can with fcntl */
148 if (fcntl(ret, F_SETFL, flags) == -1) {
149 goto fail;
150 }
151
152 /* Truncate the file in the cases that open() would truncate it */
153 if (flags & O_TRUNC ||
154 ((flags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))) {
155 if (ftruncate(ret, 0) == -1) {
156 goto fail;
157 }
158 }
159
160 return ret;
161
162 fail:
163 serrno = errno;
164 if (ret != -1) {
165 close(ret);
166 }
167 errno = serrno;
168 return -1;
169 }
170
171 int qemu_dup(int fd)
172 {
173 int ret;
174 #ifdef F_DUPFD_CLOEXEC
175 ret = fcntl(fd, F_DUPFD_CLOEXEC, 0);
176 #else
177 ret = dup(fd);
178 if (ret != -1) {
179 qemu_set_cloexec(ret);
180 }
181 #endif
182 return ret;
183 }
184
185 static int qemu_parse_fdset(const char *param)
186 {
187 return qemu_parse_fd(param);
188 }
189
190 static void qemu_probe_lock_ops(void)
191 {
192 if (fcntl_op_setlk == -1) {
193 #ifdef F_OFD_SETLK
194 int fd;
195 int ret;
196 struct flock fl = {
197 .l_whence = SEEK_SET,
198 .l_start = 0,
199 .l_len = 0,
200 .l_type = F_WRLCK,
201 };
202
203 fd = open("/dev/null", O_RDWR);
204 if (fd < 0) {
205 fprintf(stderr,
206 "Failed to open /dev/null for OFD lock probing: %s\n",
207 strerror(errno));
208 fcntl_op_setlk = F_SETLK;
209 fcntl_op_getlk = F_GETLK;
210 return;
211 }
212 ret = fcntl(fd, F_OFD_GETLK, &fl);
213 close(fd);
214 if (!ret) {
215 fcntl_op_setlk = F_OFD_SETLK;
216 fcntl_op_getlk = F_OFD_GETLK;
217 } else {
218 fcntl_op_setlk = F_SETLK;
219 fcntl_op_getlk = F_GETLK;
220 }
221 #else
222 fcntl_op_setlk = F_SETLK;
223 fcntl_op_getlk = F_GETLK;
224 #endif
225 }
226 }
227
228 bool qemu_has_ofd_lock(void)
229 {
230 qemu_probe_lock_ops();
231 #ifdef F_OFD_SETLK
232 return fcntl_op_setlk == F_OFD_SETLK;
233 #else
234 return false;
235 #endif
236 }
237
238 static int qemu_lock_fcntl(int fd, int64_t start, int64_t len, int fl_type)
239 {
240 int ret;
241 struct flock fl = {
242 .l_whence = SEEK_SET,
243 .l_start = start,
244 .l_len = len,
245 .l_type = fl_type,
246 };
247 qemu_probe_lock_ops();
248 do {
249 ret = fcntl(fd, fcntl_op_setlk, &fl);
250 } while (ret == -1 && errno == EINTR);
251 return ret == -1 ? -errno : 0;
252 }
253
254 int qemu_lock_fd(int fd, int64_t start, int64_t len, bool exclusive)
255 {
256 return qemu_lock_fcntl(fd, start, len, exclusive ? F_WRLCK : F_RDLCK);
257 }
258
259 int qemu_unlock_fd(int fd, int64_t start, int64_t len)
260 {
261 return qemu_lock_fcntl(fd, start, len, F_UNLCK);
262 }
263
264 int qemu_lock_fd_test(int fd, int64_t start, int64_t len, bool exclusive)
265 {
266 int ret;
267 struct flock fl = {
268 .l_whence = SEEK_SET,
269 .l_start = start,
270 .l_len = len,
271 .l_type = exclusive ? F_WRLCK : F_RDLCK,
272 };
273 qemu_probe_lock_ops();
274 ret = fcntl(fd, fcntl_op_getlk, &fl);
275 if (ret == -1) {
276 return -errno;
277 } else {
278 return fl.l_type == F_UNLCK ? 0 : -EAGAIN;
279 }
280 }
281 #endif
282
283 static int qemu_open_cloexec(const char *name, int flags, mode_t mode)
284 {
285 int ret;
286 #ifdef O_CLOEXEC
287 ret = open(name, flags | O_CLOEXEC, mode);
288 #else
289 ret = open(name, flags, mode);
290 if (ret >= 0) {
291 qemu_set_cloexec(ret);
292 }
293 #endif
294 return ret;
295 }
296
297 /*
298 * Opens a file with FD_CLOEXEC set
299 */
300 static int
301 qemu_open_internal(const char *name, int flags, mode_t mode, Error **errp)
302 {
303 int ret;
304
305 #ifndef _WIN32
306 const char *fdset_id_str;
307
308 /* Attempt dup of fd from fd set */
309 if (strstart(name, "/dev/fdset/", &fdset_id_str)) {
310 int64_t fdset_id;
311 int dupfd;
312
313 fdset_id = qemu_parse_fdset(fdset_id_str);
314 if (fdset_id == -1) {
315 error_setg(errp, "Could not parse fdset %s", name);
316 errno = EINVAL;
317 return -1;
318 }
319
320 dupfd = monitor_fdset_dup_fd_add(fdset_id, flags);
321 if (dupfd == -1) {
322 error_setg_errno(errp, errno, "Could not dup FD for %s flags %x",
323 name, flags);
324 return -1;
325 }
326
327 return dupfd;
328 }
329 #endif
330
331 ret = qemu_open_cloexec(name, flags, mode);
332
333 if (ret == -1) {
334 const char *action = flags & O_CREAT ? "create" : "open";
335 error_setg_errno(errp, errno, "Could not %s '%s'",
336 action, name);
337 }
338
339
340 return ret;
341 }
342
343
344 int qemu_open(const char *name, int flags, Error **errp)
345 {
346 assert(!(flags & O_CREAT));
347
348 return qemu_open_internal(name, flags, 0, errp);
349 }
350
351
352 int qemu_create(const char *name, int flags, mode_t mode, Error **errp)
353 {
354 assert(!(flags & O_CREAT));
355
356 return qemu_open_internal(name, flags | O_CREAT, mode, errp);
357 }
358
359
360 int qemu_open_old(const char *name, int flags, ...)
361 {
362 va_list ap;
363 mode_t mode = 0;
364 int ret;
365
366 va_start(ap, flags);
367 if (flags & O_CREAT) {
368 mode = va_arg(ap, int);
369 }
370 va_end(ap);
371
372 ret = qemu_open_internal(name, flags, mode, NULL);
373
374 #ifdef O_DIRECT
375 if (ret == -1 && errno == EINVAL && (flags & O_DIRECT)) {
376 error_report("file system may not support O_DIRECT");
377 errno = EINVAL; /* in case it was clobbered */
378 }
379 #endif /* O_DIRECT */
380
381 return ret;
382 }
383
384 int qemu_close(int fd)
385 {
386 int64_t fdset_id;
387
388 /* Close fd that was dup'd from an fdset */
389 fdset_id = monitor_fdset_dup_fd_find(fd);
390 if (fdset_id != -1) {
391 int ret;
392
393 ret = close(fd);
394 if (ret == 0) {
395 monitor_fdset_dup_fd_remove(fd);
396 }
397
398 return ret;
399 }
400
401 return close(fd);
402 }
403
404 /*
405 * Delete a file from the filesystem, unless the filename is /dev/fdset/...
406 *
407 * Returns: On success, zero is returned. On error, -1 is returned,
408 * and errno is set appropriately.
409 */
410 int qemu_unlink(const char *name)
411 {
412 if (g_str_has_prefix(name, "/dev/fdset/")) {
413 return 0;
414 }
415
416 return unlink(name);
417 }
418
419 /*
420 * A variant of write(2) which handles partial write.
421 *
422 * Return the number of bytes transferred.
423 * Set errno if fewer than `count' bytes are written.
424 *
425 * This function don't work with non-blocking fd's.
426 * Any of the possibilities with non-bloking fd's is bad:
427 * - return a short write (then name is wrong)
428 * - busy wait adding (errno == EAGAIN) to the loop
429 */
430 ssize_t qemu_write_full(int fd, const void *buf, size_t count)
431 {
432 ssize_t ret = 0;
433 ssize_t total = 0;
434
435 while (count) {
436 ret = write(fd, buf, count);
437 if (ret < 0) {
438 if (errno == EINTR)
439 continue;
440 break;
441 }
442
443 count -= ret;
444 buf += ret;
445 total += ret;
446 }
447
448 return total;
449 }
450
451 /*
452 * Opens a socket with FD_CLOEXEC set
453 */
454 int qemu_socket(int domain, int type, int protocol)
455 {
456 int ret;
457
458 #ifdef SOCK_CLOEXEC
459 ret = socket(domain, type | SOCK_CLOEXEC, protocol);
460 if (ret != -1 || errno != EINVAL) {
461 return ret;
462 }
463 #endif
464 ret = socket(domain, type, protocol);
465 if (ret >= 0) {
466 qemu_set_cloexec(ret);
467 }
468
469 return ret;
470 }
471
472 /*
473 * Accept a connection and set FD_CLOEXEC
474 */
475 int qemu_accept(int s, struct sockaddr *addr, socklen_t *addrlen)
476 {
477 int ret;
478
479 #ifdef CONFIG_ACCEPT4
480 ret = accept4(s, addr, addrlen, SOCK_CLOEXEC);
481 if (ret != -1 || errno != ENOSYS) {
482 return ret;
483 }
484 #endif
485 ret = accept(s, addr, addrlen);
486 if (ret >= 0) {
487 qemu_set_cloexec(ret);
488 }
489
490 return ret;
491 }
492
493 void qemu_set_hw_version(const char *version)
494 {
495 hw_version = version;
496 }
497
498 const char *qemu_hw_version(void)
499 {
500 return hw_version;
501 }
502
503 void fips_set_state(bool requested)
504 {
505 #ifdef __linux__
506 if (requested) {
507 FILE *fds = fopen("/proc/sys/crypto/fips_enabled", "r");
508 if (fds != NULL) {
509 fips_enabled = (fgetc(fds) == '1');
510 fclose(fds);
511 }
512 }
513 #else
514 fips_enabled = false;
515 #endif /* __linux__ */
516
517 #ifdef _FIPS_DEBUG
518 fprintf(stderr, "FIPS mode %s (requested %s)\n",
519 (fips_enabled ? "enabled" : "disabled"),
520 (requested ? "enabled" : "disabled"));
521 #endif
522 }
523
524 bool fips_get_state(void)
525 {
526 return fips_enabled;
527 }
528
529 #ifdef _WIN32
530 static void socket_cleanup(void)
531 {
532 WSACleanup();
533 }
534 #endif
535
536 int socket_init(void)
537 {
538 #ifdef _WIN32
539 WSADATA Data;
540 int ret, err;
541
542 ret = WSAStartup(MAKEWORD(2, 2), &Data);
543 if (ret != 0) {
544 err = WSAGetLastError();
545 fprintf(stderr, "WSAStartup: %d\n", err);
546 return -1;
547 }
548 atexit(socket_cleanup);
549 #endif
550 return 0;
551 }
552
553
554 #ifndef CONFIG_IOVEC
555 /* helper function for iov_send_recv() */
556 static ssize_t
557 readv_writev(int fd, const struct iovec *iov, int iov_cnt, bool do_write)
558 {
559 unsigned i = 0;
560 ssize_t ret = 0;
561 while (i < iov_cnt) {
562 ssize_t r = do_write
563 ? write(fd, iov[i].iov_base, iov[i].iov_len)
564 : read(fd, iov[i].iov_base, iov[i].iov_len);
565 if (r > 0) {
566 ret += r;
567 } else if (!r) {
568 break;
569 } else if (errno == EINTR) {
570 continue;
571 } else {
572 /* else it is some "other" error,
573 * only return if there was no data processed. */
574 if (ret == 0) {
575 ret = -1;
576 }
577 break;
578 }
579 i++;
580 }
581 return ret;
582 }
583
584 ssize_t
585 readv(int fd, const struct iovec *iov, int iov_cnt)
586 {
587 return readv_writev(fd, iov, iov_cnt, false);
588 }
589
590 ssize_t
591 writev(int fd, const struct iovec *iov, int iov_cnt)
592 {
593 return readv_writev(fd, iov, iov_cnt, true);
594 }
595 #endif