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(char *, 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 static int qemu_mprotect__osdep(void *addr, size_t size, int prot)
  77 {
  78     g_assert(!((uintptr_t)addr & ~qemu_real_host_page_mask));
  79     g_assert(!(size & ~qemu_real_host_page_mask));
  80
  81 #ifdef _WIN32
  82     DWORD old_protect;
  83
  84     if (!VirtualProtect(addr, size, prot, &old_protect)) {
  85         g_autofree gchar *emsg = g_win32_error_message(GetLastError());
  86         error_report("%s: VirtualProtect failed: %s", __func__, emsg);
  87         return -1;
  88     }
  89     return 0;
  90 #else
  91     if (mprotect(addr, size, prot)) {
  92         error_report("%s: mprotect failed: %s", __func__, strerror(errno));
  93         return -1;
  94     }
  95     return 0;
  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 int qemu_open(const char *name, int flags, ...)
 300 {
 301     int ret;
 302     int mode = 0;
 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             errno = EINVAL;
 315             return -1;
 316         }
 317
 318         dupfd = monitor_fdset_dup_fd_add(fdset_id, flags);
 319         if (dupfd == -1) {
 320             return -1;
 321         }
 322
 323         return dupfd;
 324     }
 325 #endif
 326
 327     if (flags & O_CREAT) {
 328         va_list ap;
 329
 330         va_start(ap, flags);
 331         mode = va_arg(ap, int);
 332         va_end(ap);
 333     }
 334
 335     ret = qemu_open_cloexec(name, flags, mode);
 336
 337 #ifdef O_DIRECT
 338     if (ret == -1 && errno == EINVAL && (flags & O_DIRECT)) {
 339         error_report("file system may not support O_DIRECT");
 340         errno = EINVAL; /* in case it was clobbered */
 341     }
 342 #endif /* O_DIRECT */
 343
 344     return ret;
 345 }
 346
 347 int qemu_close(int fd)
 348 {
 349     int64_t fdset_id;
 350
 351     /* Close fd that was dup'd from an fdset */
 352     fdset_id = monitor_fdset_dup_fd_find(fd);
 353     if (fdset_id != -1) {
 354         int ret;
 355
 356         ret = close(fd);
 357         if (ret == 0) {
 358             monitor_fdset_dup_fd_remove(fd);
 359         }
 360
 361         return ret;
 362     }
 363
 364     return close(fd);
 365 }
 366
 367 /*
 368  * Delete a file from the filesystem, unless the filename is /dev/fdset/...
 369  *
 370  * Returns: On success, zero is returned.  On error, -1 is returned,
 371  * and errno is set appropriately.
 372  */
 373 int qemu_unlink(const char *name)
 374 {
 375     if (g_str_has_prefix(name, "/dev/fdset/")) {
 376         return 0;
 377     }
 378
 379     return unlink(name);
 380 }
 381
 382 /*
 383  * A variant of write(2) which handles partial write.
 384  *
 385  * Return the number of bytes transferred.
 386  * Set errno if fewer than `count' bytes are written.
 387  *
 388  * This function don't work with non-blocking fd's.
 389  * Any of the possibilities with non-bloking fd's is bad:
 390  *   - return a short write (then name is wrong)
 391  *   - busy wait adding (errno == EAGAIN) to the loop
 392  */
 393 ssize_t qemu_write_full(int fd, const void *buf, size_t count)
 394 {
 395     ssize_t ret = 0;
 396     ssize_t total = 0;
 397
 398     while (count) {
 399         ret = write(fd, buf, count);
 400         if (ret < 0) {
 401             if (errno == EINTR)
 402                 continue;
 403             break;
 404         }
 405
 406         count -= ret;
 407         buf += ret;
 408         total += ret;
 409     }
 410
 411     return total;
 412 }
 413
 414 /*
 415  * Opens a socket with FD_CLOEXEC set
 416  */
 417 int qemu_socket(int domain, int type, int protocol)
 418 {
 419     int ret;
 420
 421 #ifdef SOCK_CLOEXEC
 422     ret = socket(domain, type | SOCK_CLOEXEC, protocol);
 423     if (ret != -1 || errno != EINVAL) {
 424         return ret;
 425     }
 426 #endif
 427     ret = socket(domain, type, protocol);
 428     if (ret >= 0) {
 429         qemu_set_cloexec(ret);
 430     }
 431
 432     return ret;
 433 }
 434
 435 /*
 436  * Accept a connection and set FD_CLOEXEC
 437  */
 438 int qemu_accept(int s, struct sockaddr *addr, socklen_t *addrlen)
 439 {
 440     int ret;
 441
 442 #ifdef CONFIG_ACCEPT4
 443     ret = accept4(s, addr, addrlen, SOCK_CLOEXEC);
 444     if (ret != -1 || errno != ENOSYS) {
 445         return ret;
 446     }
 447 #endif
 448     ret = accept(s, addr, addrlen);
 449     if (ret >= 0) {
 450         qemu_set_cloexec(ret);
 451     }
 452
 453     return ret;
 454 }
 455
 456 void qemu_set_hw_version(const char *version)
 457 {
 458     hw_version = version;
 459 }
 460
 461 const char *qemu_hw_version(void)
 462 {
 463     return hw_version;
 464 }
 465
 466 void fips_set_state(bool requested)
 467 {
 468 #ifdef __linux__
 469     if (requested) {
 470         FILE *fds = fopen("/proc/sys/crypto/fips_enabled", "r");
 471         if (fds != NULL) {
 472             fips_enabled = (fgetc(fds) == '1');
 473             fclose(fds);
 474         }
 475     }
 476 #else
 477     fips_enabled = false;
 478 #endif /* __linux__ */
 479
 480 #ifdef _FIPS_DEBUG
 481     fprintf(stderr, "FIPS mode %s (requested %s)\n",
 482             (fips_enabled ? "enabled" : "disabled"),
 483             (requested ? "enabled" : "disabled"));
 484 #endif
 485 }
 486
 487 bool fips_get_state(void)
 488 {
 489     return fips_enabled;
 490 }
 491
 492 #ifdef _WIN32
 493 static void socket_cleanup(void)
 494 {
 495     WSACleanup();
 496 }
 497 #endif
 498
 499 int socket_init(void)
 500 {
 501 #ifdef _WIN32
 502     WSADATA Data;
 503     int ret, err;
 504
 505     ret = WSAStartup(MAKEWORD(2, 2), &Data);
 506     if (ret != 0) {
 507         err = WSAGetLastError();
 508         fprintf(stderr, "WSAStartup: %d\n", err);
 509         return -1;
 510     }
 511     atexit(socket_cleanup);
 512 #endif
 513     return 0;
 514 }
 515
 516
 517 #ifndef CONFIG_IOVEC
 518 /* helper function for iov_send_recv() */
 519 static ssize_t
 520 readv_writev(int fd, const struct iovec *iov, int iov_cnt, bool do_write)
 521 {
 522     unsigned i = 0;
 523     ssize_t ret = 0;
 524     while (i < iov_cnt) {
 525         ssize_t r = do_write
 526             ? write(fd, iov[i].iov_base, iov[i].iov_len)
 527             : read(fd, iov[i].iov_base, iov[i].iov_len);
 528         if (r > 0) {
 529             ret += r;
 530         } else if (!r) {
 531             break;
 532         } else if (errno == EINTR) {
 533             continue;
 534         } else {
 535             /* else it is some "other" error,
 536              * only return if there was no data processed. */
 537             if (ret == 0) {
 538                 ret = -1;
 539             }
 540             break;
 541         }
 542         i++;
 543     }
 544     return ret;
 545 }
 546
 547 ssize_t
 548 readv(int fd, const struct iovec *iov, int iov_cnt)
 549 {
 550     return readv_writev(fd, iov, iov_cnt, false);
 551 }
 552
 553 ssize_t
 554 writev(int fd, const struct iovec *iov, int iov_cnt)
 555 {
 556     return readv_writev(fd, iov, iov_cnt, true);
 557 }
 558 #endif