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 int qemu_get_thread_id(void) 59 { 60 #if defined(__linux__) 61 return syscall(SYS_gettid); 62 #else 63 return getpid(); 64 #endif 65 } 66 67 int qemu_daemon(int nochdir, int noclose) 68 { 69 return daemon(nochdir, noclose); 70 } 71 72 void *qemu_oom_check(void *ptr) 73 { 74 if (ptr == NULL) { 75 fprintf(stderr, "Failed to allocate memory: %s\n", strerror(errno)); 76 abort(); 77 } 78 return ptr; 79 } 80 81 void *qemu_try_memalign(size_t alignment, size_t size) 82 { 83 void *ptr; 84 85 if (alignment < sizeof(void*)) { 86 alignment = sizeof(void*); 87 } 88 89 #if defined(_POSIX_C_SOURCE) && !defined(__sun__) 90 int ret; 91 ret = posix_memalign(&ptr, alignment, size); 92 if (ret != 0) { 93 errno = ret; 94 ptr = NULL; 95 } 96 #elif defined(CONFIG_BSD) 97 ptr = valloc(size); 98 #else 99 ptr = memalign(alignment, size); 100 #endif 101 trace_qemu_memalign(alignment, size, ptr); 102 return ptr; 103 } 104 105 void *qemu_memalign(size_t alignment, size_t size) 106 { 107 return qemu_oom_check(qemu_try_memalign(alignment, size)); 108 } 109 110 /* alloc shared memory pages */ 111 void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment) 112 { 113 size_t align = QEMU_VMALLOC_ALIGN; 114 void *ptr = qemu_ram_mmap(-1, size, align, false); 115 116 if (ptr == MAP_FAILED) { 117 return NULL; 118 } 119 120 if (alignment) { 121 *alignment = align; 122 } 123 124 trace_qemu_anon_ram_alloc(size, ptr); 125 return ptr; 126 } 127 128 void qemu_vfree(void *ptr) 129 { 130 trace_qemu_vfree(ptr); 131 free(ptr); 132 } 133 134 void qemu_anon_ram_free(void *ptr, size_t size) 135 { 136 trace_qemu_anon_ram_free(ptr, size); 137 qemu_ram_munmap(ptr, size); 138 } 139 140 void qemu_set_block(int fd) 141 { 142 int f; 143 f = fcntl(fd, F_GETFL); 144 fcntl(fd, F_SETFL, f & ~O_NONBLOCK); 145 } 146 147 void qemu_set_nonblock(int fd) 148 { 149 int f; 150 f = fcntl(fd, F_GETFL); 151 fcntl(fd, F_SETFL, f | O_NONBLOCK); 152 } 153 154 int socket_set_fast_reuse(int fd) 155 { 156 int val = 1, ret; 157 158 ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, 159 (const char *)&val, sizeof(val)); 160 161 assert(ret == 0); 162 163 return ret; 164 } 165 166 void qemu_set_cloexec(int fd) 167 { 168 int f; 169 f = fcntl(fd, F_GETFD); 170 fcntl(fd, F_SETFD, f | FD_CLOEXEC); 171 } 172 173 /* 174 * Creates a pipe with FD_CLOEXEC set on both file descriptors 175 */ 176 int qemu_pipe(int pipefd[2]) 177 { 178 int ret; 179 180 #ifdef CONFIG_PIPE2 181 ret = pipe2(pipefd, O_CLOEXEC); 182 if (ret != -1 || errno != ENOSYS) { 183 return ret; 184 } 185 #endif 186 ret = pipe(pipefd); 187 if (ret == 0) { 188 qemu_set_cloexec(pipefd[0]); 189 qemu_set_cloexec(pipefd[1]); 190 } 191 192 return ret; 193 } 194 195 int qemu_utimens(const char *path, const struct timespec *times) 196 { 197 struct timeval tv[2], tv_now; 198 struct stat st; 199 int i; 200 #ifdef CONFIG_UTIMENSAT 201 int ret; 202 203 ret = utimensat(AT_FDCWD, path, times, AT_SYMLINK_NOFOLLOW); 204 if (ret != -1 || errno != ENOSYS) { 205 return ret; 206 } 207 #endif 208 /* Fallback: use utimes() instead of utimensat() */ 209 210 /* happy if special cases */ 211 if (times[0].tv_nsec == UTIME_OMIT && times[1].tv_nsec == UTIME_OMIT) { 212 return 0; 213 } 214 if (times[0].tv_nsec == UTIME_NOW && times[1].tv_nsec == UTIME_NOW) { 215 return utimes(path, NULL); 216 } 217 218 /* prepare for hard cases */ 219 if (times[0].tv_nsec == UTIME_NOW || times[1].tv_nsec == UTIME_NOW) { 220 gettimeofday(&tv_now, NULL); 221 } 222 if (times[0].tv_nsec == UTIME_OMIT || times[1].tv_nsec == UTIME_OMIT) { 223 stat(path, &st); 224 } 225 226 for (i = 0; i < 2; i++) { 227 if (times[i].tv_nsec == UTIME_NOW) { 228 tv[i].tv_sec = tv_now.tv_sec; 229 tv[i].tv_usec = tv_now.tv_usec; 230 } else if (times[i].tv_nsec == UTIME_OMIT) { 231 tv[i].tv_sec = (i == 0) ? st.st_atime : st.st_mtime; 232 tv[i].tv_usec = 0; 233 } else { 234 tv[i].tv_sec = times[i].tv_sec; 235 tv[i].tv_usec = times[i].tv_nsec / 1000; 236 } 237 } 238 239 return utimes(path, &tv[0]); 240 } 241 242 char * 243 qemu_get_local_state_pathname(const char *relative_pathname) 244 { 245 return g_strdup_printf("%s/%s", CONFIG_QEMU_LOCALSTATEDIR, 246 relative_pathname); 247 } 248 249 void qemu_set_tty_echo(int fd, bool echo) 250 { 251 struct termios tty; 252 253 tcgetattr(fd, &tty); 254 255 if (echo) { 256 tty.c_lflag |= ECHO | ECHONL | ICANON | IEXTEN; 257 } else { 258 tty.c_lflag &= ~(ECHO | ECHONL | ICANON | IEXTEN); 259 } 260 261 tcsetattr(fd, TCSANOW, &tty); 262 } 263 264 static char exec_dir[PATH_MAX]; 265 266 void qemu_init_exec_dir(const char *argv0) 267 { 268 char *dir; 269 char *p = NULL; 270 char buf[PATH_MAX]; 271 272 assert(!exec_dir[0]); 273 274 #if defined(__linux__) 275 { 276 int len; 277 len = readlink("/proc/self/exe", buf, sizeof(buf) - 1); 278 if (len > 0) { 279 buf[len] = 0; 280 p = buf; 281 } 282 } 283 #elif defined(__FreeBSD__) 284 { 285 static int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1}; 286 size_t len = sizeof(buf) - 1; 287 288 *buf = '\0'; 289 if (!sysctl(mib, ARRAY_SIZE(mib), buf, &len, NULL, 0) && 290 *buf) { 291 buf[sizeof(buf) - 1] = '\0'; 292 p = buf; 293 } 294 } 295 #endif 296 /* If we don't have any way of figuring out the actual executable 297 location then try argv[0]. */ 298 if (!p) { 299 if (!argv0) { 300 return; 301 } 302 p = realpath(argv0, buf); 303 if (!p) { 304 return; 305 } 306 } 307 dir = g_path_get_dirname(p); 308 309 pstrcpy(exec_dir, sizeof(exec_dir), dir); 310 311 g_free(dir); 312 } 313 314 char *qemu_get_exec_dir(void) 315 { 316 return g_strdup(exec_dir); 317 } 318 319 static sigjmp_buf sigjump; 320 321 static void sigbus_handler(int signal) 322 { 323 siglongjmp(sigjump, 1); 324 } 325 326 void os_mem_prealloc(int fd, char *area, size_t memory, Error **errp) 327 { 328 int ret; 329 struct sigaction act, oldact; 330 sigset_t set, oldset; 331 332 memset(&act, 0, sizeof(act)); 333 act.sa_handler = &sigbus_handler; 334 act.sa_flags = 0; 335 336 ret = sigaction(SIGBUS, &act, &oldact); 337 if (ret) { 338 error_setg_errno(errp, errno, 339 "os_mem_prealloc: failed to install signal handler"); 340 return; 341 } 342 343 /* unblock SIGBUS */ 344 sigemptyset(&set); 345 sigaddset(&set, SIGBUS); 346 pthread_sigmask(SIG_UNBLOCK, &set, &oldset); 347 348 if (sigsetjmp(sigjump, 1)) { 349 error_setg(errp, "os_mem_prealloc: Insufficient free host memory " 350 "pages available to allocate guest RAM\n"); 351 } else { 352 int i; 353 size_t hpagesize = qemu_fd_getpagesize(fd); 354 size_t numpages = DIV_ROUND_UP(memory, hpagesize); 355 356 /* MAP_POPULATE silently ignores failures */ 357 for (i = 0; i < numpages; i++) { 358 memset(area + (hpagesize * i), 0, 1); 359 } 360 } 361 362 ret = sigaction(SIGBUS, &oldact, NULL); 363 if (ret) { 364 /* Terminate QEMU since it can't recover from error */ 365 perror("os_mem_prealloc: failed to reinstall signal handler"); 366 exit(1); 367 } 368 pthread_sigmask(SIG_SETMASK, &oldset, NULL); 369 } 370 371 372 static struct termios oldtty; 373 374 static void term_exit(void) 375 { 376 tcsetattr(0, TCSANOW, &oldtty); 377 } 378 379 static void term_init(void) 380 { 381 struct termios tty; 382 383 tcgetattr(0, &tty); 384 oldtty = tty; 385 386 tty.c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP 387 |INLCR|IGNCR|ICRNL|IXON); 388 tty.c_oflag |= OPOST; 389 tty.c_lflag &= ~(ECHO|ECHONL|ICANON|IEXTEN); 390 tty.c_cflag &= ~(CSIZE|PARENB); 391 tty.c_cflag |= CS8; 392 tty.c_cc[VMIN] = 1; 393 tty.c_cc[VTIME] = 0; 394 395 tcsetattr(0, TCSANOW, &tty); 396 397 atexit(term_exit); 398 } 399 400 int qemu_read_password(char *buf, int buf_size) 401 { 402 uint8_t ch; 403 int i, ret; 404 405 printf("password: "); 406 fflush(stdout); 407 term_init(); 408 i = 0; 409 for (;;) { 410 ret = read(0, &ch, 1); 411 if (ret == -1) { 412 if (errno == EAGAIN || errno == EINTR) { 413 continue; 414 } else { 415 break; 416 } 417 } else if (ret == 0) { 418 ret = -1; 419 break; 420 } else { 421 if (ch == '\r' || 422 ch == '\n') { 423 ret = 0; 424 break; 425 } 426 if (i < (buf_size - 1)) { 427 buf[i++] = ch; 428 } 429 } 430 } 431 term_exit(); 432 buf[i] = '\0'; 433 printf("\n"); 434 return ret; 435 } 436 437 438 char *qemu_get_pid_name(pid_t pid) 439 { 440 char *name = NULL; 441 442 #if defined(__FreeBSD__) 443 /* BSDs don't have /proc, but they provide a nice substitute */ 444 struct kinfo_proc *proc = kinfo_getproc(pid); 445 446 if (proc) { 447 name = g_strdup(proc->ki_comm); 448 free(proc); 449 } 450 #else 451 /* Assume a system with reasonable procfs */ 452 char *pid_path; 453 size_t len; 454 455 pid_path = g_strdup_printf("/proc/%d/cmdline", pid); 456 g_file_get_contents(pid_path, &name, &len, NULL); 457 g_free(pid_path); 458 #endif 459 460 return name; 461 } 462 463 464 pid_t qemu_fork(Error **errp) 465 { 466 sigset_t oldmask, newmask; 467 struct sigaction sig_action; 468 int saved_errno; 469 pid_t pid; 470 471 /* 472 * Need to block signals now, so that child process can safely 473 * kill off caller's signal handlers without a race. 474 */ 475 sigfillset(&newmask); 476 if (pthread_sigmask(SIG_SETMASK, &newmask, &oldmask) != 0) { 477 error_setg_errno(errp, errno, 478 "cannot block signals"); 479 return -1; 480 } 481 482 pid = fork(); 483 saved_errno = errno; 484 485 if (pid < 0) { 486 /* attempt to restore signal mask, but ignore failure, to 487 * avoid obscuring the fork failure */ 488 (void)pthread_sigmask(SIG_SETMASK, &oldmask, NULL); 489 error_setg_errno(errp, saved_errno, 490 "cannot fork child process"); 491 errno = saved_errno; 492 return -1; 493 } else if (pid) { 494 /* parent process */ 495 496 /* Restore our original signal mask now that the child is 497 * safely running. Only documented failures are EFAULT (not 498 * possible, since we are using just-grabbed mask) or EINVAL 499 * (not possible, since we are using correct arguments). */ 500 (void)pthread_sigmask(SIG_SETMASK, &oldmask, NULL); 501 } else { 502 /* child process */ 503 size_t i; 504 505 /* Clear out all signal handlers from parent so nothing 506 * unexpected can happen in our child once we unblock 507 * signals */ 508 sig_action.sa_handler = SIG_DFL; 509 sig_action.sa_flags = 0; 510 sigemptyset(&sig_action.sa_mask); 511 512 for (i = 1; i < NSIG; i++) { 513 /* Only possible errors are EFAULT or EINVAL The former 514 * won't happen, the latter we expect, so no need to check 515 * return value */ 516 (void)sigaction(i, &sig_action, NULL); 517 } 518 519 /* Unmask all signals in child, since we've no idea what the 520 * caller's done with their signal mask and don't want to 521 * propagate that to children */ 522 sigemptyset(&newmask); 523 if (pthread_sigmask(SIG_SETMASK, &newmask, NULL) != 0) { 524 Error *local_err = NULL; 525 error_setg_errno(&local_err, errno, 526 "cannot unblock signals"); 527 error_report_err(local_err); 528 _exit(1); 529 } 530 } 531 return pid; 532 } 533 534 void *qemu_alloc_stack(size_t *sz) 535 { 536 void *ptr, *guardpage; 537 #ifdef CONFIG_DEBUG_STACK_USAGE 538 void *ptr2; 539 #endif 540 size_t pagesz = getpagesize(); 541 #ifdef _SC_THREAD_STACK_MIN 542 /* avoid stacks smaller than _SC_THREAD_STACK_MIN */ 543 long min_stack_sz = sysconf(_SC_THREAD_STACK_MIN); 544 *sz = MAX(MAX(min_stack_sz, 0), *sz); 545 #endif 546 /* adjust stack size to a multiple of the page size */ 547 *sz = ROUND_UP(*sz, pagesz); 548 /* allocate one extra page for the guard page */ 549 *sz += pagesz; 550 551 ptr = mmap(NULL, *sz, PROT_READ | PROT_WRITE, 552 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); 553 if (ptr == MAP_FAILED) { 554 abort(); 555 } 556 557 #if defined(HOST_IA64) 558 /* separate register stack */ 559 guardpage = ptr + (((*sz - pagesz) / 2) & ~pagesz); 560 #elif defined(HOST_HPPA) 561 /* stack grows up */ 562 guardpage = ptr + *sz - pagesz; 563 #else 564 /* stack grows down */ 565 guardpage = ptr; 566 #endif 567 if (mprotect(guardpage, pagesz, PROT_NONE) != 0) { 568 abort(); 569 } 570 571 #ifdef CONFIG_DEBUG_STACK_USAGE 572 for (ptr2 = ptr + pagesz; ptr2 < ptr + *sz; ptr2 += sizeof(uint32_t)) { 573 *(uint32_t *)ptr2 = 0xdeadbeaf; 574 } 575 #endif 576 577 return ptr; 578 } 579 580 #ifdef CONFIG_DEBUG_STACK_USAGE 581 static __thread unsigned int max_stack_usage; 582 #endif 583 584 void qemu_free_stack(void *stack, size_t sz) 585 { 586 #ifdef CONFIG_DEBUG_STACK_USAGE 587 unsigned int usage; 588 void *ptr; 589 590 for (ptr = stack + getpagesize(); ptr < stack + sz; 591 ptr += sizeof(uint32_t)) { 592 if (*(uint32_t *)ptr != 0xdeadbeaf) { 593 break; 594 } 595 } 596 usage = sz - (uintptr_t) (ptr - stack); 597 if (usage > max_stack_usage) { 598 error_report("thread %d max stack usage increased from %u to %u", 599 qemu_get_thread_id(), max_stack_usage, usage); 600 max_stack_usage = usage; 601 } 602 #endif 603 604 munmap(stack, sz); 605 } 606