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 #include "qemu/osdep.h" 30 #include <termios.h> 31 32 #include <glib/gprintf.h> 33 34 #include "sysemu/sysemu.h" 35 #include "trace.h" 36 #include "qapi/error.h" 37 #include "qemu/sockets.h" 38 #include <libgen.h> 39 #include <sys/signal.h> 40 #include "qemu/cutils.h" 41 42 #ifdef CONFIG_LINUX 43 #include <sys/syscall.h> 44 #endif 45 46 #ifdef __FreeBSD__ 47 #include <sys/sysctl.h> 48 #include <sys/user.h> 49 #include <libutil.h> 50 #endif 51 52 #include "qemu/mmap-alloc.h" 53 54 #ifdef CONFIG_DEBUG_STACK_USAGE 55 #include "qemu/error-report.h" 56 #endif 57 58 #define MAX_MEM_PREALLOC_THREAD_COUNT 16 59 60 struct MemsetThread { 61 char *addr; 62 uint64_t numpages; 63 uint64_t hpagesize; 64 QemuThread pgthread; 65 sigjmp_buf env; 66 }; 67 typedef struct MemsetThread MemsetThread; 68 69 static MemsetThread *memset_thread; 70 static int memset_num_threads; 71 static bool memset_thread_failed; 72 73 int qemu_get_thread_id(void) 74 { 75 #if defined(__linux__) 76 return syscall(SYS_gettid); 77 #else 78 return getpid(); 79 #endif 80 } 81 82 int qemu_daemon(int nochdir, int noclose) 83 { 84 return daemon(nochdir, noclose); 85 } 86 87 void *qemu_oom_check(void *ptr) 88 { 89 if (ptr == NULL) { 90 fprintf(stderr, "Failed to allocate memory: %s\n", strerror(errno)); 91 abort(); 92 } 93 return ptr; 94 } 95 96 void *qemu_try_memalign(size_t alignment, size_t size) 97 { 98 void *ptr; 99 100 if (alignment < sizeof(void*)) { 101 alignment = sizeof(void*); 102 } 103 104 #if defined(_POSIX_C_SOURCE) && !defined(__sun__) 105 int ret; 106 ret = posix_memalign(&ptr, alignment, size); 107 if (ret != 0) { 108 errno = ret; 109 ptr = NULL; 110 } 111 #elif defined(CONFIG_BSD) 112 ptr = valloc(size); 113 #else 114 ptr = memalign(alignment, size); 115 #endif 116 trace_qemu_memalign(alignment, size, ptr); 117 return ptr; 118 } 119 120 void *qemu_memalign(size_t alignment, size_t size) 121 { 122 return qemu_oom_check(qemu_try_memalign(alignment, size)); 123 } 124 125 /* alloc shared memory pages */ 126 void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment) 127 { 128 size_t align = QEMU_VMALLOC_ALIGN; 129 void *ptr = qemu_ram_mmap(-1, size, align, false); 130 131 if (ptr == MAP_FAILED) { 132 return NULL; 133 } 134 135 if (alignment) { 136 *alignment = align; 137 } 138 139 trace_qemu_anon_ram_alloc(size, ptr); 140 return ptr; 141 } 142 143 void qemu_vfree(void *ptr) 144 { 145 trace_qemu_vfree(ptr); 146 free(ptr); 147 } 148 149 void qemu_anon_ram_free(void *ptr, size_t size) 150 { 151 trace_qemu_anon_ram_free(ptr, size); 152 qemu_ram_munmap(ptr, size); 153 } 154 155 void qemu_set_block(int fd) 156 { 157 int f; 158 f = fcntl(fd, F_GETFL); 159 fcntl(fd, F_SETFL, f & ~O_NONBLOCK); 160 } 161 162 void qemu_set_nonblock(int fd) 163 { 164 int f; 165 f = fcntl(fd, F_GETFL); 166 fcntl(fd, F_SETFL, f | O_NONBLOCK); 167 } 168 169 int socket_set_fast_reuse(int fd) 170 { 171 int val = 1, ret; 172 173 ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, 174 (const char *)&val, sizeof(val)); 175 176 assert(ret == 0); 177 178 return ret; 179 } 180 181 void qemu_set_cloexec(int fd) 182 { 183 int f; 184 f = fcntl(fd, F_GETFD); 185 fcntl(fd, F_SETFD, f | FD_CLOEXEC); 186 } 187 188 /* 189 * Creates a pipe with FD_CLOEXEC set on both file descriptors 190 */ 191 int qemu_pipe(int pipefd[2]) 192 { 193 int ret; 194 195 #ifdef CONFIG_PIPE2 196 ret = pipe2(pipefd, O_CLOEXEC); 197 if (ret != -1 || errno != ENOSYS) { 198 return ret; 199 } 200 #endif 201 ret = pipe(pipefd); 202 if (ret == 0) { 203 qemu_set_cloexec(pipefd[0]); 204 qemu_set_cloexec(pipefd[1]); 205 } 206 207 return ret; 208 } 209 210 int qemu_utimens(const char *path, const struct timespec *times) 211 { 212 struct timeval tv[2], tv_now; 213 struct stat st; 214 int i; 215 #ifdef CONFIG_UTIMENSAT 216 int ret; 217 218 ret = utimensat(AT_FDCWD, path, times, AT_SYMLINK_NOFOLLOW); 219 if (ret != -1 || errno != ENOSYS) { 220 return ret; 221 } 222 #endif 223 /* Fallback: use utimes() instead of utimensat() */ 224 225 /* happy if special cases */ 226 if (times[0].tv_nsec == UTIME_OMIT && times[1].tv_nsec == UTIME_OMIT) { 227 return 0; 228 } 229 if (times[0].tv_nsec == UTIME_NOW && times[1].tv_nsec == UTIME_NOW) { 230 return utimes(path, NULL); 231 } 232 233 /* prepare for hard cases */ 234 if (times[0].tv_nsec == UTIME_NOW || times[1].tv_nsec == UTIME_NOW) { 235 gettimeofday(&tv_now, NULL); 236 } 237 if (times[0].tv_nsec == UTIME_OMIT || times[1].tv_nsec == UTIME_OMIT) { 238 stat(path, &st); 239 } 240 241 for (i = 0; i < 2; i++) { 242 if (times[i].tv_nsec == UTIME_NOW) { 243 tv[i].tv_sec = tv_now.tv_sec; 244 tv[i].tv_usec = tv_now.tv_usec; 245 } else if (times[i].tv_nsec == UTIME_OMIT) { 246 tv[i].tv_sec = (i == 0) ? st.st_atime : st.st_mtime; 247 tv[i].tv_usec = 0; 248 } else { 249 tv[i].tv_sec = times[i].tv_sec; 250 tv[i].tv_usec = times[i].tv_nsec / 1000; 251 } 252 } 253 254 return utimes(path, &tv[0]); 255 } 256 257 char * 258 qemu_get_local_state_pathname(const char *relative_pathname) 259 { 260 return g_strdup_printf("%s/%s", CONFIG_QEMU_LOCALSTATEDIR, 261 relative_pathname); 262 } 263 264 void qemu_set_tty_echo(int fd, bool echo) 265 { 266 struct termios tty; 267 268 tcgetattr(fd, &tty); 269 270 if (echo) { 271 tty.c_lflag |= ECHO | ECHONL | ICANON | IEXTEN; 272 } else { 273 tty.c_lflag &= ~(ECHO | ECHONL | ICANON | IEXTEN); 274 } 275 276 tcsetattr(fd, TCSANOW, &tty); 277 } 278 279 static char exec_dir[PATH_MAX]; 280 281 void qemu_init_exec_dir(const char *argv0) 282 { 283 char *dir; 284 char *p = NULL; 285 char buf[PATH_MAX]; 286 287 assert(!exec_dir[0]); 288 289 #if defined(__linux__) 290 { 291 int len; 292 len = readlink("/proc/self/exe", buf, sizeof(buf) - 1); 293 if (len > 0) { 294 buf[len] = 0; 295 p = buf; 296 } 297 } 298 #elif defined(__FreeBSD__) 299 { 300 static int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1}; 301 size_t len = sizeof(buf) - 1; 302 303 *buf = '\0'; 304 if (!sysctl(mib, ARRAY_SIZE(mib), buf, &len, NULL, 0) && 305 *buf) { 306 buf[sizeof(buf) - 1] = '\0'; 307 p = buf; 308 } 309 } 310 #endif 311 /* If we don't have any way of figuring out the actual executable 312 location then try argv[0]. */ 313 if (!p) { 314 if (!argv0) { 315 return; 316 } 317 p = realpath(argv0, buf); 318 if (!p) { 319 return; 320 } 321 } 322 dir = g_path_get_dirname(p); 323 324 pstrcpy(exec_dir, sizeof(exec_dir), dir); 325 326 g_free(dir); 327 } 328 329 char *qemu_get_exec_dir(void) 330 { 331 return g_strdup(exec_dir); 332 } 333 334 static void sigbus_handler(int signal) 335 { 336 int i; 337 if (memset_thread) { 338 for (i = 0; i < memset_num_threads; i++) { 339 if (qemu_thread_is_self(&memset_thread[i].pgthread)) { 340 siglongjmp(memset_thread[i].env, 1); 341 } 342 } 343 } 344 } 345 346 static void *do_touch_pages(void *arg) 347 { 348 MemsetThread *memset_args = (MemsetThread *)arg; 349 char *addr = memset_args->addr; 350 uint64_t numpages = memset_args->numpages; 351 uint64_t hpagesize = memset_args->hpagesize; 352 sigset_t set, oldset; 353 int i = 0; 354 355 /* unblock SIGBUS */ 356 sigemptyset(&set); 357 sigaddset(&set, SIGBUS); 358 pthread_sigmask(SIG_UNBLOCK, &set, &oldset); 359 360 if (sigsetjmp(memset_args->env, 1)) { 361 memset_thread_failed = true; 362 } else { 363 for (i = 0; i < numpages; i++) { 364 /* 365 * Read & write back the same value, so we don't 366 * corrupt existing user/app data that might be 367 * stored. 368 * 369 * 'volatile' to stop compiler optimizing this away 370 * to a no-op 371 * 372 * TODO: get a better solution from kernel so we 373 * don't need to write at all so we don't cause 374 * wear on the storage backing the region... 375 */ 376 *(volatile char *)addr = *addr; 377 addr += hpagesize; 378 } 379 } 380 pthread_sigmask(SIG_SETMASK, &oldset, NULL); 381 return NULL; 382 } 383 384 static inline int get_memset_num_threads(int smp_cpus) 385 { 386 long host_procs = sysconf(_SC_NPROCESSORS_ONLN); 387 int ret = 1; 388 389 if (host_procs > 0) { 390 ret = MIN(MIN(host_procs, MAX_MEM_PREALLOC_THREAD_COUNT), smp_cpus); 391 } 392 /* In case sysconf() fails, we fall back to single threaded */ 393 return ret; 394 } 395 396 static bool touch_all_pages(char *area, size_t hpagesize, size_t numpages, 397 int smp_cpus) 398 { 399 uint64_t numpages_per_thread, size_per_thread; 400 char *addr = area; 401 int i = 0; 402 403 memset_thread_failed = false; 404 memset_num_threads = get_memset_num_threads(smp_cpus); 405 memset_thread = g_new0(MemsetThread, memset_num_threads); 406 numpages_per_thread = (numpages / memset_num_threads); 407 size_per_thread = (hpagesize * numpages_per_thread); 408 for (i = 0; i < memset_num_threads; i++) { 409 memset_thread[i].addr = addr; 410 memset_thread[i].numpages = (i == (memset_num_threads - 1)) ? 411 numpages : numpages_per_thread; 412 memset_thread[i].hpagesize = hpagesize; 413 qemu_thread_create(&memset_thread[i].pgthread, "touch_pages", 414 do_touch_pages, &memset_thread[i], 415 QEMU_THREAD_JOINABLE); 416 addr += size_per_thread; 417 numpages -= numpages_per_thread; 418 } 419 for (i = 0; i < memset_num_threads; i++) { 420 qemu_thread_join(&memset_thread[i].pgthread); 421 } 422 g_free(memset_thread); 423 memset_thread = NULL; 424 425 return memset_thread_failed; 426 } 427 428 void os_mem_prealloc(int fd, char *area, size_t memory, int smp_cpus, 429 Error **errp) 430 { 431 int ret; 432 struct sigaction act, oldact; 433 size_t hpagesize = qemu_fd_getpagesize(fd); 434 size_t numpages = DIV_ROUND_UP(memory, hpagesize); 435 436 memset(&act, 0, sizeof(act)); 437 act.sa_handler = &sigbus_handler; 438 act.sa_flags = 0; 439 440 ret = sigaction(SIGBUS, &act, &oldact); 441 if (ret) { 442 error_setg_errno(errp, errno, 443 "os_mem_prealloc: failed to install signal handler"); 444 return; 445 } 446 447 /* touch pages simultaneously */ 448 if (touch_all_pages(area, hpagesize, numpages, smp_cpus)) { 449 error_setg(errp, "os_mem_prealloc: Insufficient free host memory " 450 "pages available to allocate guest RAM\n"); 451 } 452 453 ret = sigaction(SIGBUS, &oldact, NULL); 454 if (ret) { 455 /* Terminate QEMU since it can't recover from error */ 456 perror("os_mem_prealloc: failed to reinstall signal handler"); 457 exit(1); 458 } 459 } 460 461 462 static struct termios oldtty; 463 464 static void term_exit(void) 465 { 466 tcsetattr(0, TCSANOW, &oldtty); 467 } 468 469 static void term_init(void) 470 { 471 struct termios tty; 472 473 tcgetattr(0, &tty); 474 oldtty = tty; 475 476 tty.c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP 477 |INLCR|IGNCR|ICRNL|IXON); 478 tty.c_oflag |= OPOST; 479 tty.c_lflag &= ~(ECHO|ECHONL|ICANON|IEXTEN); 480 tty.c_cflag &= ~(CSIZE|PARENB); 481 tty.c_cflag |= CS8; 482 tty.c_cc[VMIN] = 1; 483 tty.c_cc[VTIME] = 0; 484 485 tcsetattr(0, TCSANOW, &tty); 486 487 atexit(term_exit); 488 } 489 490 int qemu_read_password(char *buf, int buf_size) 491 { 492 uint8_t ch; 493 int i, ret; 494 495 printf("password: "); 496 fflush(stdout); 497 term_init(); 498 i = 0; 499 for (;;) { 500 ret = read(0, &ch, 1); 501 if (ret == -1) { 502 if (errno == EAGAIN || errno == EINTR) { 503 continue; 504 } else { 505 break; 506 } 507 } else if (ret == 0) { 508 ret = -1; 509 break; 510 } else { 511 if (ch == '\r' || 512 ch == '\n') { 513 ret = 0; 514 break; 515 } 516 if (i < (buf_size - 1)) { 517 buf[i++] = ch; 518 } 519 } 520 } 521 term_exit(); 522 buf[i] = '\0'; 523 printf("\n"); 524 return ret; 525 } 526 527 528 char *qemu_get_pid_name(pid_t pid) 529 { 530 char *name = NULL; 531 532 #if defined(__FreeBSD__) 533 /* BSDs don't have /proc, but they provide a nice substitute */ 534 struct kinfo_proc *proc = kinfo_getproc(pid); 535 536 if (proc) { 537 name = g_strdup(proc->ki_comm); 538 free(proc); 539 } 540 #else 541 /* Assume a system with reasonable procfs */ 542 char *pid_path; 543 size_t len; 544 545 pid_path = g_strdup_printf("/proc/%d/cmdline", pid); 546 g_file_get_contents(pid_path, &name, &len, NULL); 547 g_free(pid_path); 548 #endif 549 550 return name; 551 } 552 553 554 pid_t qemu_fork(Error **errp) 555 { 556 sigset_t oldmask, newmask; 557 struct sigaction sig_action; 558 int saved_errno; 559 pid_t pid; 560 561 /* 562 * Need to block signals now, so that child process can safely 563 * kill off caller's signal handlers without a race. 564 */ 565 sigfillset(&newmask); 566 if (pthread_sigmask(SIG_SETMASK, &newmask, &oldmask) != 0) { 567 error_setg_errno(errp, errno, 568 "cannot block signals"); 569 return -1; 570 } 571 572 pid = fork(); 573 saved_errno = errno; 574 575 if (pid < 0) { 576 /* attempt to restore signal mask, but ignore failure, to 577 * avoid obscuring the fork failure */ 578 (void)pthread_sigmask(SIG_SETMASK, &oldmask, NULL); 579 error_setg_errno(errp, saved_errno, 580 "cannot fork child process"); 581 errno = saved_errno; 582 return -1; 583 } else if (pid) { 584 /* parent process */ 585 586 /* Restore our original signal mask now that the child is 587 * safely running. Only documented failures are EFAULT (not 588 * possible, since we are using just-grabbed mask) or EINVAL 589 * (not possible, since we are using correct arguments). */ 590 (void)pthread_sigmask(SIG_SETMASK, &oldmask, NULL); 591 } else { 592 /* child process */ 593 size_t i; 594 595 /* Clear out all signal handlers from parent so nothing 596 * unexpected can happen in our child once we unblock 597 * signals */ 598 sig_action.sa_handler = SIG_DFL; 599 sig_action.sa_flags = 0; 600 sigemptyset(&sig_action.sa_mask); 601 602 for (i = 1; i < NSIG; i++) { 603 /* Only possible errors are EFAULT or EINVAL The former 604 * won't happen, the latter we expect, so no need to check 605 * return value */ 606 (void)sigaction(i, &sig_action, NULL); 607 } 608 609 /* Unmask all signals in child, since we've no idea what the 610 * caller's done with their signal mask and don't want to 611 * propagate that to children */ 612 sigemptyset(&newmask); 613 if (pthread_sigmask(SIG_SETMASK, &newmask, NULL) != 0) { 614 Error *local_err = NULL; 615 error_setg_errno(&local_err, errno, 616 "cannot unblock signals"); 617 error_report_err(local_err); 618 _exit(1); 619 } 620 } 621 return pid; 622 } 623 624 void *qemu_alloc_stack(size_t *sz) 625 { 626 void *ptr, *guardpage; 627 #ifdef CONFIG_DEBUG_STACK_USAGE 628 void *ptr2; 629 #endif 630 size_t pagesz = getpagesize(); 631 #ifdef _SC_THREAD_STACK_MIN 632 /* avoid stacks smaller than _SC_THREAD_STACK_MIN */ 633 long min_stack_sz = sysconf(_SC_THREAD_STACK_MIN); 634 *sz = MAX(MAX(min_stack_sz, 0), *sz); 635 #endif 636 /* adjust stack size to a multiple of the page size */ 637 *sz = ROUND_UP(*sz, pagesz); 638 /* allocate one extra page for the guard page */ 639 *sz += pagesz; 640 641 ptr = mmap(NULL, *sz, PROT_READ | PROT_WRITE, 642 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); 643 if (ptr == MAP_FAILED) { 644 abort(); 645 } 646 647 #if defined(HOST_IA64) 648 /* separate register stack */ 649 guardpage = ptr + (((*sz - pagesz) / 2) & ~pagesz); 650 #elif defined(HOST_HPPA) 651 /* stack grows up */ 652 guardpage = ptr + *sz - pagesz; 653 #else 654 /* stack grows down */ 655 guardpage = ptr; 656 #endif 657 if (mprotect(guardpage, pagesz, PROT_NONE) != 0) { 658 abort(); 659 } 660 661 #ifdef CONFIG_DEBUG_STACK_USAGE 662 for (ptr2 = ptr + pagesz; ptr2 < ptr + *sz; ptr2 += sizeof(uint32_t)) { 663 *(uint32_t *)ptr2 = 0xdeadbeaf; 664 } 665 #endif 666 667 return ptr; 668 } 669 670 #ifdef CONFIG_DEBUG_STACK_USAGE 671 static __thread unsigned int max_stack_usage; 672 #endif 673 674 void qemu_free_stack(void *stack, size_t sz) 675 { 676 #ifdef CONFIG_DEBUG_STACK_USAGE 677 unsigned int usage; 678 void *ptr; 679 680 for (ptr = stack + getpagesize(); ptr < stack + sz; 681 ptr += sizeof(uint32_t)) { 682 if (*(uint32_t *)ptr != 0xdeadbeaf) { 683 break; 684 } 685 } 686 usage = sz - (uintptr_t) (ptr - stack); 687 if (usage > max_stack_usage) { 688 error_report("thread %d max stack usage increased from %u to %u", 689 qemu_get_thread_id(), max_stack_usage, usage); 690 max_stack_usage = usage; 691 } 692 #endif 693 694 munmap(stack, sz); 695 } 696 697 void sigaction_invoke(struct sigaction *action, 698 struct qemu_signalfd_siginfo *info) 699 { 700 siginfo_t si = { 0 }; 701 si.si_signo = info->ssi_signo; 702 si.si_errno = info->ssi_errno; 703 si.si_code = info->ssi_code; 704 705 /* Convert the minimal set of fields defined by POSIX. 706 * Positive si_code values are reserved for kernel-generated 707 * signals, where the valid siginfo fields are determined by 708 * the signal number. But according to POSIX, it is unspecified 709 * whether SI_USER and SI_QUEUE have values less than or equal to 710 * zero. 711 */ 712 if (info->ssi_code == SI_USER || info->ssi_code == SI_QUEUE || 713 info->ssi_code <= 0) { 714 /* SIGTERM, etc. */ 715 si.si_pid = info->ssi_pid; 716 si.si_uid = info->ssi_uid; 717 } else if (info->ssi_signo == SIGILL || info->ssi_signo == SIGFPE || 718 info->ssi_signo == SIGSEGV || info->ssi_signo == SIGBUS) { 719 si.si_addr = (void *)(uintptr_t)info->ssi_addr; 720 } else if (info->ssi_signo == SIGCHLD) { 721 si.si_pid = info->ssi_pid; 722 si.si_status = info->ssi_status; 723 si.si_uid = info->ssi_uid; 724 } 725 action->sa_sigaction(info->ssi_signo, &si, NULL); 726 } 727