1 /* 2 * os-posix-lib.c 3 * 4 * Copyright (c) 2003-2008 Fabrice Bellard 5 * Copyright (c) 2010 Red Hat, Inc. 6 * 7 * QEMU library functions on POSIX which are shared between QEMU and 8 * the QEMU tools. 9 * 10 * Permission is hereby granted, free of charge, to any person obtaining a copy 11 * of this software and associated documentation files (the "Software"), to deal 12 * in the Software without restriction, including without limitation the rights 13 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 14 * copies of the Software, and to permit persons to whom the Software is 15 * furnished to do so, subject to the following conditions: 16 * 17 * The above copyright notice and this permission notice shall be included in 18 * all copies or substantial portions of the Software. 19 * 20 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 21 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 22 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 23 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 24 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 25 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 26 * THE SOFTWARE. 27 */ 28 29 /* The following block of code temporarily renames the daemon() function so the 30 compiler does not see the warning associated with it in stdlib.h on OSX */ 31 #ifdef __APPLE__ 32 #define daemon qemu_fake_daemon_function 33 #include <stdlib.h> 34 #undef daemon 35 extern int daemon(int, int); 36 #endif 37 38 #if defined(__linux__) && (defined(__x86_64__) || defined(__arm__)) 39 /* Use 2 MiB alignment so transparent hugepages can be used by KVM. 40 Valgrind does not support alignments larger than 1 MiB, 41 therefore we need special code which handles running on Valgrind. */ 42 # define QEMU_VMALLOC_ALIGN (512 * 4096) 43 #elif defined(__linux__) && defined(__s390x__) 44 /* Use 1 MiB (segment size) alignment so gmap can be used by KVM. */ 45 # define QEMU_VMALLOC_ALIGN (256 * 4096) 46 #else 47 # define QEMU_VMALLOC_ALIGN getpagesize() 48 #endif 49 #define HUGETLBFS_MAGIC 0x958458f6 50 51 #include <termios.h> 52 #include <unistd.h> 53 #include <termios.h> 54 55 #include <glib/gprintf.h> 56 57 #include "config-host.h" 58 #include "sysemu/sysemu.h" 59 #include "trace.h" 60 #include "qemu/sockets.h" 61 #include <sys/mman.h> 62 #include <libgen.h> 63 #include <setjmp.h> 64 #include <sys/signal.h> 65 66 #ifdef CONFIG_LINUX 67 #include <sys/syscall.h> 68 #include <sys/vfs.h> 69 #endif 70 71 #ifdef __FreeBSD__ 72 #include <sys/sysctl.h> 73 #endif 74 75 #include <qemu/mmap-alloc.h> 76 77 int qemu_get_thread_id(void) 78 { 79 #if defined(__linux__) 80 return syscall(SYS_gettid); 81 #else 82 return getpid(); 83 #endif 84 } 85 86 int qemu_daemon(int nochdir, int noclose) 87 { 88 return daemon(nochdir, noclose); 89 } 90 91 void *qemu_oom_check(void *ptr) 92 { 93 if (ptr == NULL) { 94 fprintf(stderr, "Failed to allocate memory: %s\n", strerror(errno)); 95 abort(); 96 } 97 return ptr; 98 } 99 100 void *qemu_try_memalign(size_t alignment, size_t size) 101 { 102 void *ptr; 103 104 if (alignment < sizeof(void*)) { 105 alignment = sizeof(void*); 106 } 107 108 #if defined(_POSIX_C_SOURCE) && !defined(__sun__) 109 int ret; 110 ret = posix_memalign(&ptr, alignment, size); 111 if (ret != 0) { 112 errno = ret; 113 ptr = NULL; 114 } 115 #elif defined(CONFIG_BSD) 116 ptr = valloc(size); 117 #else 118 ptr = memalign(alignment, size); 119 #endif 120 trace_qemu_memalign(alignment, size, ptr); 121 return ptr; 122 } 123 124 void *qemu_memalign(size_t alignment, size_t size) 125 { 126 return qemu_oom_check(qemu_try_memalign(alignment, size)); 127 } 128 129 /* alloc shared memory pages */ 130 void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment) 131 { 132 size_t align = QEMU_VMALLOC_ALIGN; 133 void *ptr = qemu_ram_mmap(-1, size, align, false); 134 135 if (ptr == MAP_FAILED) { 136 return NULL; 137 } 138 139 if (alignment) { 140 *alignment = align; 141 } 142 143 trace_qemu_anon_ram_alloc(size, ptr); 144 return ptr; 145 } 146 147 void qemu_vfree(void *ptr) 148 { 149 trace_qemu_vfree(ptr); 150 free(ptr); 151 } 152 153 void qemu_anon_ram_free(void *ptr, size_t size) 154 { 155 trace_qemu_anon_ram_free(ptr, size); 156 qemu_ram_munmap(ptr, size); 157 } 158 159 void qemu_set_block(int fd) 160 { 161 int f; 162 f = fcntl(fd, F_GETFL); 163 fcntl(fd, F_SETFL, f & ~O_NONBLOCK); 164 } 165 166 void qemu_set_nonblock(int fd) 167 { 168 int f; 169 f = fcntl(fd, F_GETFL); 170 fcntl(fd, F_SETFL, f | O_NONBLOCK); 171 } 172 173 int socket_set_fast_reuse(int fd) 174 { 175 int val = 1, ret; 176 177 ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, 178 (const char *)&val, sizeof(val)); 179 180 assert(ret == 0); 181 182 return ret; 183 } 184 185 void qemu_set_cloexec(int fd) 186 { 187 int f; 188 f = fcntl(fd, F_GETFD); 189 fcntl(fd, F_SETFD, f | FD_CLOEXEC); 190 } 191 192 /* 193 * Creates a pipe with FD_CLOEXEC set on both file descriptors 194 */ 195 int qemu_pipe(int pipefd[2]) 196 { 197 int ret; 198 199 #ifdef CONFIG_PIPE2 200 ret = pipe2(pipefd, O_CLOEXEC); 201 if (ret != -1 || errno != ENOSYS) { 202 return ret; 203 } 204 #endif 205 ret = pipe(pipefd); 206 if (ret == 0) { 207 qemu_set_cloexec(pipefd[0]); 208 qemu_set_cloexec(pipefd[1]); 209 } 210 211 return ret; 212 } 213 214 int qemu_utimens(const char *path, const struct timespec *times) 215 { 216 struct timeval tv[2], tv_now; 217 struct stat st; 218 int i; 219 #ifdef CONFIG_UTIMENSAT 220 int ret; 221 222 ret = utimensat(AT_FDCWD, path, times, AT_SYMLINK_NOFOLLOW); 223 if (ret != -1 || errno != ENOSYS) { 224 return ret; 225 } 226 #endif 227 /* Fallback: use utimes() instead of utimensat() */ 228 229 /* happy if special cases */ 230 if (times[0].tv_nsec == UTIME_OMIT && times[1].tv_nsec == UTIME_OMIT) { 231 return 0; 232 } 233 if (times[0].tv_nsec == UTIME_NOW && times[1].tv_nsec == UTIME_NOW) { 234 return utimes(path, NULL); 235 } 236 237 /* prepare for hard cases */ 238 if (times[0].tv_nsec == UTIME_NOW || times[1].tv_nsec == UTIME_NOW) { 239 gettimeofday(&tv_now, NULL); 240 } 241 if (times[0].tv_nsec == UTIME_OMIT || times[1].tv_nsec == UTIME_OMIT) { 242 stat(path, &st); 243 } 244 245 for (i = 0; i < 2; i++) { 246 if (times[i].tv_nsec == UTIME_NOW) { 247 tv[i].tv_sec = tv_now.tv_sec; 248 tv[i].tv_usec = tv_now.tv_usec; 249 } else if (times[i].tv_nsec == UTIME_OMIT) { 250 tv[i].tv_sec = (i == 0) ? st.st_atime : st.st_mtime; 251 tv[i].tv_usec = 0; 252 } else { 253 tv[i].tv_sec = times[i].tv_sec; 254 tv[i].tv_usec = times[i].tv_nsec / 1000; 255 } 256 } 257 258 return utimes(path, &tv[0]); 259 } 260 261 char * 262 qemu_get_local_state_pathname(const char *relative_pathname) 263 { 264 return g_strdup_printf("%s/%s", CONFIG_QEMU_LOCALSTATEDIR, 265 relative_pathname); 266 } 267 268 void qemu_set_tty_echo(int fd, bool echo) 269 { 270 struct termios tty; 271 272 tcgetattr(fd, &tty); 273 274 if (echo) { 275 tty.c_lflag |= ECHO | ECHONL | ICANON | IEXTEN; 276 } else { 277 tty.c_lflag &= ~(ECHO | ECHONL | ICANON | IEXTEN); 278 } 279 280 tcsetattr(fd, TCSANOW, &tty); 281 } 282 283 static char exec_dir[PATH_MAX]; 284 285 void qemu_init_exec_dir(const char *argv0) 286 { 287 char *dir; 288 char *p = NULL; 289 char buf[PATH_MAX]; 290 291 assert(!exec_dir[0]); 292 293 #if defined(__linux__) 294 { 295 int len; 296 len = readlink("/proc/self/exe", buf, sizeof(buf) - 1); 297 if (len > 0) { 298 buf[len] = 0; 299 p = buf; 300 } 301 } 302 #elif defined(__FreeBSD__) 303 { 304 static int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1}; 305 size_t len = sizeof(buf) - 1; 306 307 *buf = '\0'; 308 if (!sysctl(mib, ARRAY_SIZE(mib), buf, &len, NULL, 0) && 309 *buf) { 310 buf[sizeof(buf) - 1] = '\0'; 311 p = buf; 312 } 313 } 314 #endif 315 /* If we don't have any way of figuring out the actual executable 316 location then try argv[0]. */ 317 if (!p) { 318 if (!argv0) { 319 return; 320 } 321 p = realpath(argv0, buf); 322 if (!p) { 323 return; 324 } 325 } 326 dir = dirname(p); 327 328 pstrcpy(exec_dir, sizeof(exec_dir), dir); 329 } 330 331 char *qemu_get_exec_dir(void) 332 { 333 return g_strdup(exec_dir); 334 } 335 336 static sigjmp_buf sigjump; 337 338 static void sigbus_handler(int signal) 339 { 340 siglongjmp(sigjump, 1); 341 } 342 343 static size_t fd_getpagesize(int fd) 344 { 345 #ifdef CONFIG_LINUX 346 struct statfs fs; 347 int ret; 348 349 if (fd != -1) { 350 do { 351 ret = fstatfs(fd, &fs); 352 } while (ret != 0 && errno == EINTR); 353 354 if (ret == 0 && fs.f_type == HUGETLBFS_MAGIC) { 355 return fs.f_bsize; 356 } 357 } 358 #endif 359 360 return getpagesize(); 361 } 362 363 void os_mem_prealloc(int fd, char *area, size_t memory) 364 { 365 int ret; 366 struct sigaction act, oldact; 367 sigset_t set, oldset; 368 369 memset(&act, 0, sizeof(act)); 370 act.sa_handler = &sigbus_handler; 371 act.sa_flags = 0; 372 373 ret = sigaction(SIGBUS, &act, &oldact); 374 if (ret) { 375 perror("os_mem_prealloc: failed to install signal handler"); 376 exit(1); 377 } 378 379 /* unblock SIGBUS */ 380 sigemptyset(&set); 381 sigaddset(&set, SIGBUS); 382 pthread_sigmask(SIG_UNBLOCK, &set, &oldset); 383 384 if (sigsetjmp(sigjump, 1)) { 385 fprintf(stderr, "os_mem_prealloc: Insufficient free host memory " 386 "pages available to allocate guest RAM\n"); 387 exit(1); 388 } else { 389 int i; 390 size_t hpagesize = fd_getpagesize(fd); 391 size_t numpages = DIV_ROUND_UP(memory, hpagesize); 392 393 /* MAP_POPULATE silently ignores failures */ 394 for (i = 0; i < numpages; i++) { 395 memset(area + (hpagesize * i), 0, 1); 396 } 397 398 ret = sigaction(SIGBUS, &oldact, NULL); 399 if (ret) { 400 perror("os_mem_prealloc: failed to reinstall signal handler"); 401 exit(1); 402 } 403 404 pthread_sigmask(SIG_SETMASK, &oldset, NULL); 405 } 406 } 407 408 409 static struct termios oldtty; 410 411 static void term_exit(void) 412 { 413 tcsetattr(0, TCSANOW, &oldtty); 414 } 415 416 static void term_init(void) 417 { 418 struct termios tty; 419 420 tcgetattr(0, &tty); 421 oldtty = tty; 422 423 tty.c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP 424 |INLCR|IGNCR|ICRNL|IXON); 425 tty.c_oflag |= OPOST; 426 tty.c_lflag &= ~(ECHO|ECHONL|ICANON|IEXTEN); 427 tty.c_cflag &= ~(CSIZE|PARENB); 428 tty.c_cflag |= CS8; 429 tty.c_cc[VMIN] = 1; 430 tty.c_cc[VTIME] = 0; 431 432 tcsetattr(0, TCSANOW, &tty); 433 434 atexit(term_exit); 435 } 436 437 int qemu_read_password(char *buf, int buf_size) 438 { 439 uint8_t ch; 440 int i, ret; 441 442 printf("password: "); 443 fflush(stdout); 444 term_init(); 445 i = 0; 446 for (;;) { 447 ret = read(0, &ch, 1); 448 if (ret == -1) { 449 if (errno == EAGAIN || errno == EINTR) { 450 continue; 451 } else { 452 break; 453 } 454 } else if (ret == 0) { 455 ret = -1; 456 break; 457 } else { 458 if (ch == '\r' || 459 ch == '\n') { 460 ret = 0; 461 break; 462 } 463 if (i < (buf_size - 1)) { 464 buf[i++] = ch; 465 } 466 } 467 } 468 term_exit(); 469 buf[i] = '\0'; 470 printf("\n"); 471 return ret; 472 } 473 474 475 pid_t qemu_fork(Error **errp) 476 { 477 sigset_t oldmask, newmask; 478 struct sigaction sig_action; 479 int saved_errno; 480 pid_t pid; 481 482 /* 483 * Need to block signals now, so that child process can safely 484 * kill off caller's signal handlers without a race. 485 */ 486 sigfillset(&newmask); 487 if (pthread_sigmask(SIG_SETMASK, &newmask, &oldmask) != 0) { 488 error_setg_errno(errp, errno, 489 "cannot block signals"); 490 return -1; 491 } 492 493 pid = fork(); 494 saved_errno = errno; 495 496 if (pid < 0) { 497 /* attempt to restore signal mask, but ignore failure, to 498 * avoid obscuring the fork failure */ 499 (void)pthread_sigmask(SIG_SETMASK, &oldmask, NULL); 500 error_setg_errno(errp, saved_errno, 501 "cannot fork child process"); 502 errno = saved_errno; 503 return -1; 504 } else if (pid) { 505 /* parent process */ 506 507 /* Restore our original signal mask now that the child is 508 * safely running. Only documented failures are EFAULT (not 509 * possible, since we are using just-grabbed mask) or EINVAL 510 * (not possible, since we are using correct arguments). */ 511 (void)pthread_sigmask(SIG_SETMASK, &oldmask, NULL); 512 } else { 513 /* child process */ 514 size_t i; 515 516 /* Clear out all signal handlers from parent so nothing 517 * unexpected can happen in our child once we unblock 518 * signals */ 519 sig_action.sa_handler = SIG_DFL; 520 sig_action.sa_flags = 0; 521 sigemptyset(&sig_action.sa_mask); 522 523 for (i = 1; i < NSIG; i++) { 524 /* Only possible errors are EFAULT or EINVAL The former 525 * won't happen, the latter we expect, so no need to check 526 * return value */ 527 (void)sigaction(i, &sig_action, NULL); 528 } 529 530 /* Unmask all signals in child, since we've no idea what the 531 * caller's done with their signal mask and don't want to 532 * propagate that to children */ 533 sigemptyset(&newmask); 534 if (pthread_sigmask(SIG_SETMASK, &newmask, NULL) != 0) { 535 Error *local_err = NULL; 536 error_setg_errno(&local_err, errno, 537 "cannot unblock signals"); 538 error_report_err(local_err); 539 _exit(1); 540 } 541 } 542 return pid; 543 } 544