osdep.c (14122B)
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 #include "qemu/cutils.h" 27 #include "qemu/sockets.h" 28 #include "qemu/error-report.h" 29 #include "qemu/madvise.h" 30 #include "qemu/mprotect.h" 31 #include "qemu/hw-version.h" 32 #include "monitor/monitor.h" 33 34 static const char *hw_version = QEMU_HW_VERSION; 35 36 int socket_set_cork(int fd, int v) 37 { 38 #if defined(SOL_TCP) && defined(TCP_CORK) 39 return setsockopt(fd, SOL_TCP, TCP_CORK, &v, sizeof(v)); 40 #else 41 return 0; 42 #endif 43 } 44 45 int socket_set_nodelay(int fd) 46 { 47 int v = 1; 48 return setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &v, sizeof(v)); 49 } 50 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) 60 return posix_madvise(addr, len, advice); 61 #else 62 errno = EINVAL; 63 return -1; 64 #endif 65 } 66 67 static int qemu_mprotect__osdep(void *addr, size_t size, int prot) 68 { 69 g_assert(!((uintptr_t)addr & ~qemu_real_host_page_mask())); 70 g_assert(!(size & ~qemu_real_host_page_mask())); 71 72 #ifdef _WIN32 73 DWORD old_protect; 74 75 if (!VirtualProtect(addr, size, prot, &old_protect)) { 76 g_autofree gchar *emsg = g_win32_error_message(GetLastError()); 77 error_report("%s: VirtualProtect failed: %s", __func__, emsg); 78 return -1; 79 } 80 return 0; 81 #else 82 if (mprotect(addr, size, prot)) { 83 error_report("%s: mprotect failed: %s", __func__, strerror(errno)); 84 return -1; 85 } 86 return 0; 87 #endif 88 } 89 90 int qemu_mprotect_rw(void *addr, size_t size) 91 { 92 #ifdef _WIN32 93 return qemu_mprotect__osdep(addr, size, PAGE_READWRITE); 94 #else 95 return qemu_mprotect__osdep(addr, size, PROT_READ | PROT_WRITE); 96 #endif 97 } 98 99 int qemu_mprotect_rwx(void *addr, size_t size) 100 { 101 #ifdef _WIN32 102 return qemu_mprotect__osdep(addr, size, PAGE_EXECUTE_READWRITE); 103 #else 104 return qemu_mprotect__osdep(addr, size, PROT_READ | PROT_WRITE | PROT_EXEC); 105 #endif 106 } 107 108 int qemu_mprotect_none(void *addr, size_t size) 109 { 110 #ifdef _WIN32 111 return qemu_mprotect__osdep(addr, size, PAGE_NOACCESS); 112 #else 113 return qemu_mprotect__osdep(addr, size, PROT_NONE); 114 #endif 115 } 116 117 #ifndef _WIN32 118 119 static int fcntl_op_setlk = -1; 120 static int fcntl_op_getlk = -1; 121 122 /* 123 * Dups an fd and sets the flags 124 */ 125 int qemu_dup_flags(int fd, int flags) 126 { 127 int ret; 128 int serrno; 129 int dup_flags; 130 131 ret = qemu_dup(fd); 132 if (ret == -1) { 133 goto fail; 134 } 135 136 dup_flags = fcntl(ret, F_GETFL); 137 if (dup_flags == -1) { 138 goto fail; 139 } 140 141 if ((flags & O_SYNC) != (dup_flags & O_SYNC)) { 142 errno = EINVAL; 143 goto fail; 144 } 145 146 /* Set/unset flags that we can with fcntl */ 147 if (fcntl(ret, F_SETFL, flags) == -1) { 148 goto fail; 149 } 150 151 /* Truncate the file in the cases that open() would truncate it */ 152 if (flags & O_TRUNC || 153 ((flags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))) { 154 if (ftruncate(ret, 0) == -1) { 155 goto fail; 156 } 157 } 158 159 return ret; 160 161 fail: 162 serrno = errno; 163 if (ret != -1) { 164 close(ret); 165 } 166 errno = serrno; 167 return -1; 168 } 169 170 int qemu_dup(int fd) 171 { 172 int ret; 173 #ifdef F_DUPFD_CLOEXEC 174 ret = fcntl(fd, F_DUPFD_CLOEXEC, 0); 175 #else 176 ret = dup(fd); 177 if (ret != -1) { 178 qemu_set_cloexec(ret); 179 } 180 #endif 181 return ret; 182 } 183 184 static int qemu_parse_fdset(const char *param) 185 { 186 return qemu_parse_fd(param); 187 } 188 189 static void qemu_probe_lock_ops(void) 190 { 191 if (fcntl_op_setlk == -1) { 192 #ifdef F_OFD_SETLK 193 int fd; 194 int ret; 195 struct flock fl = { 196 .l_whence = SEEK_SET, 197 .l_start = 0, 198 .l_len = 0, 199 .l_type = F_WRLCK, 200 }; 201 202 fd = open("/dev/null", O_RDWR); 203 if (fd < 0) { 204 fprintf(stderr, 205 "Failed to open /dev/null for OFD lock probing: %s\n", 206 strerror(errno)); 207 fcntl_op_setlk = F_SETLK; 208 fcntl_op_getlk = F_GETLK; 209 return; 210 } 211 ret = fcntl(fd, F_OFD_GETLK, &fl); 212 close(fd); 213 if (!ret) { 214 fcntl_op_setlk = F_OFD_SETLK; 215 fcntl_op_getlk = F_OFD_GETLK; 216 } else { 217 fcntl_op_setlk = F_SETLK; 218 fcntl_op_getlk = F_GETLK; 219 } 220 #else 221 fcntl_op_setlk = F_SETLK; 222 fcntl_op_getlk = F_GETLK; 223 #endif 224 } 225 } 226 227 bool qemu_has_ofd_lock(void) 228 { 229 qemu_probe_lock_ops(); 230 #ifdef F_OFD_SETLK 231 return fcntl_op_setlk == F_OFD_SETLK; 232 #else 233 return false; 234 #endif 235 } 236 237 static int qemu_lock_fcntl(int fd, int64_t start, int64_t len, int fl_type) 238 { 239 int ret; 240 struct flock fl = { 241 .l_whence = SEEK_SET, 242 .l_start = start, 243 .l_len = len, 244 .l_type = fl_type, 245 }; 246 qemu_probe_lock_ops(); 247 do { 248 ret = fcntl(fd, fcntl_op_setlk, &fl); 249 } while (ret == -1 && errno == EINTR); 250 return ret == -1 ? -errno : 0; 251 } 252 253 int qemu_lock_fd(int fd, int64_t start, int64_t len, bool exclusive) 254 { 255 return qemu_lock_fcntl(fd, start, len, exclusive ? F_WRLCK : F_RDLCK); 256 } 257 258 int qemu_unlock_fd(int fd, int64_t start, int64_t len) 259 { 260 return qemu_lock_fcntl(fd, start, len, F_UNLCK); 261 } 262 263 int qemu_lock_fd_test(int fd, int64_t start, int64_t len, bool exclusive) 264 { 265 int ret; 266 struct flock fl = { 267 .l_whence = SEEK_SET, 268 .l_start = start, 269 .l_len = len, 270 .l_type = exclusive ? F_WRLCK : F_RDLCK, 271 }; 272 qemu_probe_lock_ops(); 273 ret = fcntl(fd, fcntl_op_getlk, &fl); 274 if (ret == -1) { 275 return -errno; 276 } else { 277 return fl.l_type == F_UNLCK ? 0 : -EAGAIN; 278 } 279 } 280 #endif 281 282 static int qemu_open_cloexec(const char *name, int flags, mode_t mode) 283 { 284 int ret; 285 #ifdef O_CLOEXEC 286 ret = open(name, flags | O_CLOEXEC, mode); 287 #else 288 ret = open(name, flags, mode); 289 if (ret >= 0) { 290 qemu_set_cloexec(ret); 291 } 292 #endif 293 return ret; 294 } 295 296 /* 297 * Opens a file with FD_CLOEXEC set 298 */ 299 static int 300 qemu_open_internal(const char *name, int flags, mode_t mode, Error **errp) 301 { 302 int ret; 303 304 #ifndef _WIN32 305 const char *fdset_id_str; 306 307 /* Attempt dup of fd from fd set */ 308 if (strstart(name, "/dev/fdset/", &fdset_id_str)) { 309 int64_t fdset_id; 310 int dupfd; 311 312 fdset_id = qemu_parse_fdset(fdset_id_str); 313 if (fdset_id == -1) { 314 error_setg(errp, "Could not parse fdset %s", name); 315 errno = EINVAL; 316 return -1; 317 } 318 319 dupfd = monitor_fdset_dup_fd_add(fdset_id, flags); 320 if (dupfd == -1) { 321 error_setg_errno(errp, errno, "Could not dup FD for %s flags %x", 322 name, flags); 323 return -1; 324 } 325 326 return dupfd; 327 } 328 #endif 329 330 ret = qemu_open_cloexec(name, flags, mode); 331 332 if (ret == -1) { 333 const char *action = flags & O_CREAT ? "create" : "open"; 334 #ifdef O_DIRECT 335 /* Give more helpful error message for O_DIRECT */ 336 if (errno == EINVAL && (flags & O_DIRECT)) { 337 ret = open(name, flags & ~O_DIRECT, mode); 338 if (ret != -1) { 339 close(ret); 340 error_setg(errp, "Could not %s '%s': " 341 "filesystem does not support O_DIRECT", 342 action, name); 343 errno = EINVAL; /* restore first open()'s errno */ 344 return -1; 345 } 346 } 347 #endif /* O_DIRECT */ 348 error_setg_errno(errp, errno, "Could not %s '%s'", 349 action, name); 350 } 351 352 return ret; 353 } 354 355 356 int qemu_open(const char *name, int flags, Error **errp) 357 { 358 assert(!(flags & O_CREAT)); 359 360 return qemu_open_internal(name, flags, 0, errp); 361 } 362 363 364 int qemu_create(const char *name, int flags, mode_t mode, Error **errp) 365 { 366 assert(!(flags & O_CREAT)); 367 368 return qemu_open_internal(name, flags | O_CREAT, mode, errp); 369 } 370 371 372 int qemu_open_old(const char *name, int flags, ...) 373 { 374 va_list ap; 375 mode_t mode = 0; 376 int ret; 377 378 va_start(ap, flags); 379 if (flags & O_CREAT) { 380 mode = va_arg(ap, int); 381 } 382 va_end(ap); 383 384 ret = qemu_open_internal(name, flags, mode, NULL); 385 386 #ifdef O_DIRECT 387 if (ret == -1 && errno == EINVAL && (flags & O_DIRECT)) { 388 error_report("file system may not support O_DIRECT"); 389 errno = EINVAL; /* in case it was clobbered */ 390 } 391 #endif /* O_DIRECT */ 392 393 return ret; 394 } 395 396 int qemu_close(int fd) 397 { 398 int64_t fdset_id; 399 400 /* Close fd that was dup'd from an fdset */ 401 fdset_id = monitor_fdset_dup_fd_find(fd); 402 if (fdset_id != -1) { 403 int ret; 404 405 ret = close(fd); 406 if (ret == 0) { 407 monitor_fdset_dup_fd_remove(fd); 408 } 409 410 return ret; 411 } 412 413 return close(fd); 414 } 415 416 /* 417 * Delete a file from the filesystem, unless the filename is /dev/fdset/... 418 * 419 * Returns: On success, zero is returned. On error, -1 is returned, 420 * and errno is set appropriately. 421 */ 422 int qemu_unlink(const char *name) 423 { 424 if (g_str_has_prefix(name, "/dev/fdset/")) { 425 return 0; 426 } 427 428 return unlink(name); 429 } 430 431 /* 432 * A variant of write(2) which handles partial write. 433 * 434 * Return the number of bytes transferred. 435 * Set errno if fewer than `count' bytes are written. 436 * 437 * This function don't work with non-blocking fd's. 438 * Any of the possibilities with non-blocking fd's is bad: 439 * - return a short write (then name is wrong) 440 * - busy wait adding (errno == EAGAIN) to the loop 441 */ 442 ssize_t qemu_write_full(int fd, const void *buf, size_t count) 443 { 444 ssize_t ret = 0; 445 ssize_t total = 0; 446 447 while (count) { 448 ret = write(fd, buf, count); 449 if (ret < 0) { 450 if (errno == EINTR) 451 continue; 452 break; 453 } 454 455 count -= ret; 456 buf += ret; 457 total += ret; 458 } 459 460 return total; 461 } 462 463 /* 464 * Opens a socket with FD_CLOEXEC set 465 */ 466 int qemu_socket(int domain, int type, int protocol) 467 { 468 int ret; 469 470 #ifdef SOCK_CLOEXEC 471 ret = socket(domain, type | SOCK_CLOEXEC, protocol); 472 if (ret != -1 || errno != EINVAL) { 473 return ret; 474 } 475 #endif 476 ret = socket(domain, type, protocol); 477 if (ret >= 0) { 478 qemu_set_cloexec(ret); 479 } 480 481 return ret; 482 } 483 484 /* 485 * Accept a connection and set FD_CLOEXEC 486 */ 487 int qemu_accept(int s, struct sockaddr *addr, socklen_t *addrlen) 488 { 489 int ret; 490 491 #ifdef CONFIG_ACCEPT4 492 ret = accept4(s, addr, addrlen, SOCK_CLOEXEC); 493 if (ret != -1 || errno != ENOSYS) { 494 return ret; 495 } 496 #endif 497 ret = accept(s, addr, addrlen); 498 if (ret >= 0) { 499 qemu_set_cloexec(ret); 500 } 501 502 return ret; 503 } 504 505 ssize_t qemu_send_full(int s, const void *buf, size_t count) 506 { 507 ssize_t ret = 0; 508 ssize_t total = 0; 509 510 while (count) { 511 ret = send(s, buf, count, 0); 512 if (ret < 0) { 513 if (errno == EINTR) { 514 continue; 515 } 516 break; 517 } 518 519 count -= ret; 520 buf += ret; 521 total += ret; 522 } 523 524 return total; 525 } 526 527 void qemu_set_hw_version(const char *version) 528 { 529 hw_version = version; 530 } 531 532 const char *qemu_hw_version(void) 533 { 534 return hw_version; 535 } 536 537 #ifdef _WIN32 538 static void socket_cleanup(void) 539 { 540 WSACleanup(); 541 } 542 #endif 543 544 int socket_init(void) 545 { 546 #ifdef _WIN32 547 WSADATA Data; 548 int ret, err; 549 550 ret = WSAStartup(MAKEWORD(2, 2), &Data); 551 if (ret != 0) { 552 err = WSAGetLastError(); 553 fprintf(stderr, "WSAStartup: %d\n", err); 554 return -1; 555 } 556 atexit(socket_cleanup); 557 #endif 558 return 0; 559 } 560 561 562 #ifndef CONFIG_IOVEC 563 static ssize_t 564 readv_writev(int fd, const struct iovec *iov, int iov_cnt, bool do_write) 565 { 566 unsigned i = 0; 567 ssize_t ret = 0; 568 ssize_t off = 0; 569 while (i < iov_cnt) { 570 ssize_t r = do_write 571 ? write(fd, iov[i].iov_base + off, iov[i].iov_len - off) 572 : read(fd, iov[i].iov_base + off, iov[i].iov_len - off); 573 if (r > 0) { 574 ret += r; 575 off += r; 576 if (off < iov[i].iov_len) { 577 continue; 578 } 579 } else if (!r) { 580 break; 581 } else if (errno == EINTR) { 582 continue; 583 } else { 584 /* else it is some "other" error, 585 * only return if there was no data processed. */ 586 if (ret == 0) { 587 ret = -1; 588 } 589 break; 590 } 591 off = 0; 592 i++; 593 } 594 return ret; 595 } 596 597 ssize_t 598 readv(int fd, const struct iovec *iov, int iov_cnt) 599 { 600 return readv_writev(fd, iov, iov_cnt, false); 601 } 602 603 ssize_t 604 writev(int fd, const struct iovec *iov, int iov_cnt) 605 { 606 return readv_writev(fd, iov, iov_cnt, true); 607 } 608 #endif 609 610 /* 611 * Make sure data goes on disk, but if possible do not bother to 612 * write out the inode just for timestamp updates. 613 * 614 * Unfortunately even in 2009 many operating systems do not support 615 * fdatasync and have to fall back to fsync. 616 */ 617 int qemu_fdatasync(int fd) 618 { 619 #ifdef CONFIG_FDATASYNC 620 return fdatasync(fd); 621 #else 622 return fsync(fd); 623 #endif 624 }