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