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 50 #include "qemu/osdep.h" 51 #include <termios.h> 52 #include <termios.h> 53 54 #include <glib/gprintf.h> 55 56 #include "sysemu/sysemu.h" 57 #include "trace.h" 58 #include "qemu/sockets.h" 59 #include <sys/mman.h> 60 #include <libgen.h> 61 #include <setjmp.h> 62 #include <sys/signal.h> 63 64 #ifdef CONFIG_LINUX 65 #include <sys/syscall.h> 66 #endif 67 68 #ifdef __FreeBSD__ 69 #include <sys/sysctl.h> 70 #endif 71 72 #include <qemu/mmap-alloc.h> 73 74 int qemu_get_thread_id(void) 75 { 76 #if defined(__linux__) 77 return syscall(SYS_gettid); 78 #else 79 return getpid(); 80 #endif 81 } 82 83 int qemu_daemon(int nochdir, int noclose) 84 { 85 return daemon(nochdir, noclose); 86 } 87 88 void *qemu_oom_check(void *ptr) 89 { 90 if (ptr == NULL) { 91 fprintf(stderr, "Failed to allocate memory: %s\n", strerror(errno)); 92 abort(); 93 } 94 return ptr; 95 } 96 97 void *qemu_try_memalign(size_t alignment, size_t size) 98 { 99 void *ptr; 100 101 if (alignment < sizeof(void*)) { 102 alignment = sizeof(void*); 103 } 104 105 #if defined(_POSIX_C_SOURCE) && !defined(__sun__) 106 int ret; 107 ret = posix_memalign(&ptr, alignment, size); 108 if (ret != 0) { 109 errno = ret; 110 ptr = NULL; 111 } 112 #elif defined(CONFIG_BSD) 113 ptr = valloc(size); 114 #else 115 ptr = memalign(alignment, size); 116 #endif 117 trace_qemu_memalign(alignment, size, ptr); 118 return ptr; 119 } 120 121 void *qemu_memalign(size_t alignment, size_t size) 122 { 123 return qemu_oom_check(qemu_try_memalign(alignment, size)); 124 } 125 126 /* alloc shared memory pages */ 127 void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment) 128 { 129 size_t align = QEMU_VMALLOC_ALIGN; 130 void *ptr = qemu_ram_mmap(-1, size, align, false); 131 132 if (ptr == MAP_FAILED) { 133 return NULL; 134 } 135 136 if (alignment) { 137 *alignment = align; 138 } 139 140 trace_qemu_anon_ram_alloc(size, ptr); 141 return ptr; 142 } 143 144 void qemu_vfree(void *ptr) 145 { 146 trace_qemu_vfree(ptr); 147 free(ptr); 148 } 149 150 void qemu_anon_ram_free(void *ptr, size_t size) 151 { 152 trace_qemu_anon_ram_free(ptr, size); 153 qemu_ram_munmap(ptr, size); 154 } 155 156 void qemu_set_block(int fd) 157 { 158 int f; 159 f = fcntl(fd, F_GETFL); 160 fcntl(fd, F_SETFL, f & ~O_NONBLOCK); 161 } 162 163 void qemu_set_nonblock(int fd) 164 { 165 int f; 166 f = fcntl(fd, F_GETFL); 167 fcntl(fd, F_SETFL, f | O_NONBLOCK); 168 } 169 170 int socket_set_fast_reuse(int fd) 171 { 172 int val = 1, ret; 173 174 ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, 175 (const char *)&val, sizeof(val)); 176 177 assert(ret == 0); 178 179 return ret; 180 } 181 182 void qemu_set_cloexec(int fd) 183 { 184 int f; 185 f = fcntl(fd, F_GETFD); 186 fcntl(fd, F_SETFD, f | FD_CLOEXEC); 187 } 188 189 /* 190 * Creates a pipe with FD_CLOEXEC set on both file descriptors 191 */ 192 int qemu_pipe(int pipefd[2]) 193 { 194 int ret; 195 196 #ifdef CONFIG_PIPE2 197 ret = pipe2(pipefd, O_CLOEXEC); 198 if (ret != -1 || errno != ENOSYS) { 199 return ret; 200 } 201 #endif 202 ret = pipe(pipefd); 203 if (ret == 0) { 204 qemu_set_cloexec(pipefd[0]); 205 qemu_set_cloexec(pipefd[1]); 206 } 207 208 return ret; 209 } 210 211 int qemu_utimens(const char *path, const struct timespec *times) 212 { 213 struct timeval tv[2], tv_now; 214 struct stat st; 215 int i; 216 #ifdef CONFIG_UTIMENSAT 217 int ret; 218 219 ret = utimensat(AT_FDCWD, path, times, AT_SYMLINK_NOFOLLOW); 220 if (ret != -1 || errno != ENOSYS) { 221 return ret; 222 } 223 #endif 224 /* Fallback: use utimes() instead of utimensat() */ 225 226 /* happy if special cases */ 227 if (times[0].tv_nsec == UTIME_OMIT && times[1].tv_nsec == UTIME_OMIT) { 228 return 0; 229 } 230 if (times[0].tv_nsec == UTIME_NOW && times[1].tv_nsec == UTIME_NOW) { 231 return utimes(path, NULL); 232 } 233 234 /* prepare for hard cases */ 235 if (times[0].tv_nsec == UTIME_NOW || times[1].tv_nsec == UTIME_NOW) { 236 gettimeofday(&tv_now, NULL); 237 } 238 if (times[0].tv_nsec == UTIME_OMIT || times[1].tv_nsec == UTIME_OMIT) { 239 stat(path, &st); 240 } 241 242 for (i = 0; i < 2; i++) { 243 if (times[i].tv_nsec == UTIME_NOW) { 244 tv[i].tv_sec = tv_now.tv_sec; 245 tv[i].tv_usec = tv_now.tv_usec; 246 } else if (times[i].tv_nsec == UTIME_OMIT) { 247 tv[i].tv_sec = (i == 0) ? st.st_atime : st.st_mtime; 248 tv[i].tv_usec = 0; 249 } else { 250 tv[i].tv_sec = times[i].tv_sec; 251 tv[i].tv_usec = times[i].tv_nsec / 1000; 252 } 253 } 254 255 return utimes(path, &tv[0]); 256 } 257 258 char * 259 qemu_get_local_state_pathname(const char *relative_pathname) 260 { 261 return g_strdup_printf("%s/%s", CONFIG_QEMU_LOCALSTATEDIR, 262 relative_pathname); 263 } 264 265 void qemu_set_tty_echo(int fd, bool echo) 266 { 267 struct termios tty; 268 269 tcgetattr(fd, &tty); 270 271 if (echo) { 272 tty.c_lflag |= ECHO | ECHONL | ICANON | IEXTEN; 273 } else { 274 tty.c_lflag &= ~(ECHO | ECHONL | ICANON | IEXTEN); 275 } 276 277 tcsetattr(fd, TCSANOW, &tty); 278 } 279 280 static char exec_dir[PATH_MAX]; 281 282 void qemu_init_exec_dir(const char *argv0) 283 { 284 char *dir; 285 char *p = NULL; 286 char buf[PATH_MAX]; 287 288 assert(!exec_dir[0]); 289 290 #if defined(__linux__) 291 { 292 int len; 293 len = readlink("/proc/self/exe", buf, sizeof(buf) - 1); 294 if (len > 0) { 295 buf[len] = 0; 296 p = buf; 297 } 298 } 299 #elif defined(__FreeBSD__) 300 { 301 static int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1}; 302 size_t len = sizeof(buf) - 1; 303 304 *buf = '\0'; 305 if (!sysctl(mib, ARRAY_SIZE(mib), buf, &len, NULL, 0) && 306 *buf) { 307 buf[sizeof(buf) - 1] = '\0'; 308 p = buf; 309 } 310 } 311 #endif 312 /* If we don't have any way of figuring out the actual executable 313 location then try argv[0]. */ 314 if (!p) { 315 if (!argv0) { 316 return; 317 } 318 p = realpath(argv0, buf); 319 if (!p) { 320 return; 321 } 322 } 323 dir = dirname(p); 324 325 pstrcpy(exec_dir, sizeof(exec_dir), dir); 326 } 327 328 char *qemu_get_exec_dir(void) 329 { 330 return g_strdup(exec_dir); 331 } 332 333 static sigjmp_buf sigjump; 334 335 static void sigbus_handler(int signal) 336 { 337 siglongjmp(sigjump, 1); 338 } 339 340 void os_mem_prealloc(int fd, char *area, size_t memory) 341 { 342 int ret; 343 struct sigaction act, oldact; 344 sigset_t set, oldset; 345 346 memset(&act, 0, sizeof(act)); 347 act.sa_handler = &sigbus_handler; 348 act.sa_flags = 0; 349 350 ret = sigaction(SIGBUS, &act, &oldact); 351 if (ret) { 352 perror("os_mem_prealloc: failed to install signal handler"); 353 exit(1); 354 } 355 356 /* unblock SIGBUS */ 357 sigemptyset(&set); 358 sigaddset(&set, SIGBUS); 359 pthread_sigmask(SIG_UNBLOCK, &set, &oldset); 360 361 if (sigsetjmp(sigjump, 1)) { 362 fprintf(stderr, "os_mem_prealloc: Insufficient free host memory " 363 "pages available to allocate guest RAM\n"); 364 exit(1); 365 } else { 366 int i; 367 size_t hpagesize = qemu_fd_getpagesize(fd); 368 size_t numpages = DIV_ROUND_UP(memory, hpagesize); 369 370 /* MAP_POPULATE silently ignores failures */ 371 for (i = 0; i < numpages; i++) { 372 memset(area + (hpagesize * i), 0, 1); 373 } 374 375 ret = sigaction(SIGBUS, &oldact, NULL); 376 if (ret) { 377 perror("os_mem_prealloc: failed to reinstall signal handler"); 378 exit(1); 379 } 380 381 pthread_sigmask(SIG_SETMASK, &oldset, NULL); 382 } 383 } 384 385 386 static struct termios oldtty; 387 388 static void term_exit(void) 389 { 390 tcsetattr(0, TCSANOW, &oldtty); 391 } 392 393 static void term_init(void) 394 { 395 struct termios tty; 396 397 tcgetattr(0, &tty); 398 oldtty = tty; 399 400 tty.c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP 401 |INLCR|IGNCR|ICRNL|IXON); 402 tty.c_oflag |= OPOST; 403 tty.c_lflag &= ~(ECHO|ECHONL|ICANON|IEXTEN); 404 tty.c_cflag &= ~(CSIZE|PARENB); 405 tty.c_cflag |= CS8; 406 tty.c_cc[VMIN] = 1; 407 tty.c_cc[VTIME] = 0; 408 409 tcsetattr(0, TCSANOW, &tty); 410 411 atexit(term_exit); 412 } 413 414 int qemu_read_password(char *buf, int buf_size) 415 { 416 uint8_t ch; 417 int i, ret; 418 419 printf("password: "); 420 fflush(stdout); 421 term_init(); 422 i = 0; 423 for (;;) { 424 ret = read(0, &ch, 1); 425 if (ret == -1) { 426 if (errno == EAGAIN || errno == EINTR) { 427 continue; 428 } else { 429 break; 430 } 431 } else if (ret == 0) { 432 ret = -1; 433 break; 434 } else { 435 if (ch == '\r' || 436 ch == '\n') { 437 ret = 0; 438 break; 439 } 440 if (i < (buf_size - 1)) { 441 buf[i++] = ch; 442 } 443 } 444 } 445 term_exit(); 446 buf[i] = '\0'; 447 printf("\n"); 448 return ret; 449 } 450 451 452 pid_t qemu_fork(Error **errp) 453 { 454 sigset_t oldmask, newmask; 455 struct sigaction sig_action; 456 int saved_errno; 457 pid_t pid; 458 459 /* 460 * Need to block signals now, so that child process can safely 461 * kill off caller's signal handlers without a race. 462 */ 463 sigfillset(&newmask); 464 if (pthread_sigmask(SIG_SETMASK, &newmask, &oldmask) != 0) { 465 error_setg_errno(errp, errno, 466 "cannot block signals"); 467 return -1; 468 } 469 470 pid = fork(); 471 saved_errno = errno; 472 473 if (pid < 0) { 474 /* attempt to restore signal mask, but ignore failure, to 475 * avoid obscuring the fork failure */ 476 (void)pthread_sigmask(SIG_SETMASK, &oldmask, NULL); 477 error_setg_errno(errp, saved_errno, 478 "cannot fork child process"); 479 errno = saved_errno; 480 return -1; 481 } else if (pid) { 482 /* parent process */ 483 484 /* Restore our original signal mask now that the child is 485 * safely running. Only documented failures are EFAULT (not 486 * possible, since we are using just-grabbed mask) or EINVAL 487 * (not possible, since we are using correct arguments). */ 488 (void)pthread_sigmask(SIG_SETMASK, &oldmask, NULL); 489 } else { 490 /* child process */ 491 size_t i; 492 493 /* Clear out all signal handlers from parent so nothing 494 * unexpected can happen in our child once we unblock 495 * signals */ 496 sig_action.sa_handler = SIG_DFL; 497 sig_action.sa_flags = 0; 498 sigemptyset(&sig_action.sa_mask); 499 500 for (i = 1; i < NSIG; i++) { 501 /* Only possible errors are EFAULT or EINVAL The former 502 * won't happen, the latter we expect, so no need to check 503 * return value */ 504 (void)sigaction(i, &sig_action, NULL); 505 } 506 507 /* Unmask all signals in child, since we've no idea what the 508 * caller's done with their signal mask and don't want to 509 * propagate that to children */ 510 sigemptyset(&newmask); 511 if (pthread_sigmask(SIG_SETMASK, &newmask, NULL) != 0) { 512 Error *local_err = NULL; 513 error_setg_errno(&local_err, errno, 514 "cannot unblock signals"); 515 error_report_err(local_err); 516 _exit(1); 517 } 518 } 519 return pid; 520 } 521