util/oslib-posix.c

   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 <libutil.h>
  49 #endif
  50
  51 #include "qemu/mmap-alloc.h"
  52
  53 #ifdef CONFIG_DEBUG_STACK_USAGE
  54 #include "qemu/error-report.h"
  55 #endif
  56
  57 int qemu_get_thread_id(void)
  58 {
  59 #if defined(__linux__)
  60     return syscall(SYS_gettid);
  61 #else
  62     return getpid();
  63 #endif
  64 }
  65
  66 int qemu_daemon(int nochdir, int noclose)
  67 {
  68     return daemon(nochdir, noclose);
  69 }
  70
  71 void *qemu_oom_check(void *ptr)
  72 {
  73     if (ptr == NULL) {
  74         fprintf(stderr, "Failed to allocate memory: %s\n", strerror(errno));
  75         abort();
  76     }
  77     return ptr;
  78 }
  79
  80 void *qemu_try_memalign(size_t alignment, size_t size)
  81 {
  82     void *ptr;
  83
  84     if (alignment < sizeof(void*)) {
  85         alignment = sizeof(void*);
  86     }
  87
  88 #if defined(_POSIX_C_SOURCE) && !defined(__sun__)
  89     int ret;
  90     ret = posix_memalign(&ptr, alignment, size);
  91     if (ret != 0) {
  92         errno = ret;
  93         ptr = NULL;
  94     }
  95 #elif defined(CONFIG_BSD)
  96     ptr = valloc(size);
  97 #else
  98     ptr = memalign(alignment, size);
  99 #endif
 100     trace_qemu_memalign(alignment, size, ptr);
 101     return ptr;
 102 }
 103
 104 void *qemu_memalign(size_t alignment, size_t size)
 105 {
 106     return qemu_oom_check(qemu_try_memalign(alignment, size));
 107 }
 108
 109 /* alloc shared memory pages */
 110 void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment)
 111 {
 112     size_t align = QEMU_VMALLOC_ALIGN;
 113     void *ptr = qemu_ram_mmap(-1, size, align, false);
 114
 115     if (ptr == MAP_FAILED) {
 116         return NULL;
 117     }
 118
 119     if (alignment) {
 120         *alignment = align;
 121     }
 122
 123     trace_qemu_anon_ram_alloc(size, ptr);
 124     return ptr;
 125 }
 126
 127 void qemu_vfree(void *ptr)
 128 {
 129     trace_qemu_vfree(ptr);
 130     free(ptr);
 131 }
 132
 133 void qemu_anon_ram_free(void *ptr, size_t size)
 134 {
 135     trace_qemu_anon_ram_free(ptr, size);
 136     qemu_ram_munmap(ptr, size);
 137 }
 138
 139 void qemu_set_block(int fd)
 140 {
 141     int f;
 142     f = fcntl(fd, F_GETFL);
 143     fcntl(fd, F_SETFL, f & ~O_NONBLOCK);
 144 }
 145
 146 void qemu_set_nonblock(int fd)
 147 {
 148     int f;
 149     f = fcntl(fd, F_GETFL);
 150     fcntl(fd, F_SETFL, f | O_NONBLOCK);
 151 }
 152
 153 int socket_set_fast_reuse(int fd)
 154 {
 155     int val = 1, ret;
 156
 157     ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR,
 158                      (const char *)&val, sizeof(val));
 159
 160     assert(ret == 0);
 161
 162     return ret;
 163 }
 164
 165 void qemu_set_cloexec(int fd)
 166 {
 167     int f;
 168     f = fcntl(fd, F_GETFD);
 169     fcntl(fd, F_SETFD, f | FD_CLOEXEC);
 170 }
 171
 172 /*
 173  * Creates a pipe with FD_CLOEXEC set on both file descriptors
 174  */
 175 int qemu_pipe(int pipefd[2])
 176 {
 177     int ret;
 178
 179 #ifdef CONFIG_PIPE2
 180     ret = pipe2(pipefd, O_CLOEXEC);
 181     if (ret != -1 || errno != ENOSYS) {
 182         return ret;
 183     }
 184 #endif
 185     ret = pipe(pipefd);
 186     if (ret == 0) {
 187         qemu_set_cloexec(pipefd[0]);
 188         qemu_set_cloexec(pipefd[1]);
 189     }
 190
 191     return ret;
 192 }
 193
 194 int qemu_utimens(const char *path, const struct timespec *times)
 195 {
 196     struct timeval tv[2], tv_now;
 197     struct stat st;
 198     int i;
 199 #ifdef CONFIG_UTIMENSAT
 200     int ret;
 201
 202     ret = utimensat(AT_FDCWD, path, times, AT_SYMLINK_NOFOLLOW);
 203     if (ret != -1 || errno != ENOSYS) {
 204         return ret;
 205     }
 206 #endif
 207     /* Fallback: use utimes() instead of utimensat() */
 208
 209     /* happy if special cases */
 210     if (times[0].tv_nsec == UTIME_OMIT && times[1].tv_nsec == UTIME_OMIT) {
 211         return 0;
 212     }
 213     if (times[0].tv_nsec == UTIME_NOW && times[1].tv_nsec == UTIME_NOW) {
 214         return utimes(path, NULL);
 215     }
 216
 217     /* prepare for hard cases */
 218     if (times[0].tv_nsec == UTIME_NOW || times[1].tv_nsec == UTIME_NOW) {
 219         gettimeofday(&tv_now, NULL);
 220     }
 221     if (times[0].tv_nsec == UTIME_OMIT || times[1].tv_nsec == UTIME_OMIT) {
 222         stat(path, &st);
 223     }
 224
 225     for (i = 0; i < 2; i++) {
 226         if (times[i].tv_nsec == UTIME_NOW) {
 227             tv[i].tv_sec = tv_now.tv_sec;
 228             tv[i].tv_usec = tv_now.tv_usec;
 229         } else if (times[i].tv_nsec == UTIME_OMIT) {
 230             tv[i].tv_sec = (i == 0) ? st.st_atime : st.st_mtime;
 231             tv[i].tv_usec = 0;
 232         } else {
 233             tv[i].tv_sec = times[i].tv_sec;
 234             tv[i].tv_usec = times[i].tv_nsec / 1000;
 235         }
 236     }
 237
 238     return utimes(path, &tv[0]);
 239 }
 240
 241 char *
 242 qemu_get_local_state_pathname(const char *relative_pathname)
 243 {
 244     return g_strdup_printf("%s/%s", CONFIG_QEMU_LOCALSTATEDIR,
 245                            relative_pathname);
 246 }
 247
 248 void qemu_set_tty_echo(int fd, bool echo)
 249 {
 250     struct termios tty;
 251
 252     tcgetattr(fd, &tty);
 253
 254     if (echo) {
 255         tty.c_lflag |= ECHO | ECHONL | ICANON | IEXTEN;
 256     } else {
 257         tty.c_lflag &= ~(ECHO | ECHONL | ICANON | IEXTEN);
 258     }
 259
 260     tcsetattr(fd, TCSANOW, &tty);
 261 }
 262
 263 static char exec_dir[PATH_MAX];
 264
 265 void qemu_init_exec_dir(const char *argv0)
 266 {
 267     char *dir;
 268     char *p = NULL;
 269     char buf[PATH_MAX];
 270
 271     assert(!exec_dir[0]);
 272
 273 #if defined(__linux__)
 274     {
 275         int len;
 276         len = readlink("/proc/self/exe", buf, sizeof(buf) - 1);
 277         if (len > 0) {
 278             buf[len] = 0;
 279             p = buf;
 280         }
 281     }
 282 #elif defined(__FreeBSD__)
 283     {
 284         static int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1};
 285         size_t len = sizeof(buf) - 1;
 286
 287         *buf = '\0';
 288         if (!sysctl(mib, ARRAY_SIZE(mib), buf, &len, NULL, 0) &&
 289             *buf) {
 290             buf[sizeof(buf) - 1] = '\0';
 291             p = buf;
 292         }
 293     }
 294 #endif
 295     /* If we don't have any way of figuring out the actual executable
 296        location then try argv[0].  */
 297     if (!p) {
 298         if (!argv0) {
 299             return;
 300         }
 301         p = realpath(argv0, buf);
 302         if (!p) {
 303             return;
 304         }
 305     }
 306     dir = g_path_get_dirname(p);
 307
 308     pstrcpy(exec_dir, sizeof(exec_dir), dir);
 309
 310     g_free(dir);
 311 }
 312
 313 char *qemu_get_exec_dir(void)
 314 {
 315     return g_strdup(exec_dir);
 316 }
 317
 318 static sigjmp_buf sigjump;
 319
 320 static void sigbus_handler(int signal)
 321 {
 322     siglongjmp(sigjump, 1);
 323 }
 324
 325 void os_mem_prealloc(int fd, char *area, size_t memory, Error **errp)
 326 {
 327     int ret;
 328     struct sigaction act, oldact;
 329     sigset_t set, oldset;
 330
 331     memset(&act, 0, sizeof(act));
 332     act.sa_handler = &sigbus_handler;
 333     act.sa_flags = 0;
 334
 335     ret = sigaction(SIGBUS, &act, &oldact);
 336     if (ret) {
 337         error_setg_errno(errp, errno,
 338             "os_mem_prealloc: failed to install signal handler");
 339         return;
 340     }
 341
 342     /* unblock SIGBUS */
 343     sigemptyset(&set);
 344     sigaddset(&set, SIGBUS);
 345     pthread_sigmask(SIG_UNBLOCK, &set, &oldset);
 346
 347     if (sigsetjmp(sigjump, 1)) {
 348         error_setg(errp, "os_mem_prealloc: Insufficient free host memory "
 349             "pages available to allocate guest RAM\n");
 350     } else {
 351         int i;
 352         size_t hpagesize = qemu_fd_getpagesize(fd);
 353         size_t numpages = DIV_ROUND_UP(memory, hpagesize);
 354
 355         /* MAP_POPULATE silently ignores failures */
 356         for (i = 0; i < numpages; i++) {
 357             memset(area + (hpagesize * i), 0, 1);
 358         }
 359     }
 360
 361     ret = sigaction(SIGBUS, &oldact, NULL);
 362     if (ret) {
 363         /* Terminate QEMU since it can't recover from error */
 364         perror("os_mem_prealloc: failed to reinstall signal handler");
 365         exit(1);
 366     }
 367     pthread_sigmask(SIG_SETMASK, &oldset, NULL);
 368 }
 369
 370
 371 static struct termios oldtty;
 372
 373 static void term_exit(void)
 374 {
 375     tcsetattr(0, TCSANOW, &oldtty);
 376 }
 377
 378 static void term_init(void)
 379 {
 380     struct termios tty;
 381
 382     tcgetattr(0, &tty);
 383     oldtty = tty;
 384
 385     tty.c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP
 386                           |INLCR|IGNCR|ICRNL|IXON);
 387     tty.c_oflag |= OPOST;
 388     tty.c_lflag &= ~(ECHO|ECHONL|ICANON|IEXTEN);
 389     tty.c_cflag &= ~(CSIZE|PARENB);
 390     tty.c_cflag |= CS8;
 391     tty.c_cc[VMIN] = 1;
 392     tty.c_cc[VTIME] = 0;
 393
 394     tcsetattr(0, TCSANOW, &tty);
 395
 396     atexit(term_exit);
 397 }
 398
 399 int qemu_read_password(char *buf, int buf_size)
 400 {
 401     uint8_t ch;
 402     int i, ret;
 403
 404     printf("password: ");
 405     fflush(stdout);
 406     term_init();
 407     i = 0;
 408     for (;;) {
 409         ret = read(0, &ch, 1);
 410         if (ret == -1) {
 411             if (errno == EAGAIN || errno == EINTR) {
 412                 continue;
 413             } else {
 414                 break;
 415             }
 416         } else if (ret == 0) {
 417             ret = -1;
 418             break;
 419         } else {
 420             if (ch == '\r' ||
 421                 ch == '\n') {
 422                 ret = 0;
 423                 break;
 424             }
 425             if (i < (buf_size - 1)) {
 426                 buf[i++] = ch;
 427             }
 428         }
 429     }
 430     term_exit();
 431     buf[i] = '\0';
 432     printf("\n");
 433     return ret;
 434 }
 435
 436
 437 char *qemu_get_pid_name(pid_t pid)
 438 {
 439     char *name = NULL;
 440
 441 #if defined(__FreeBSD__)
 442     /* BSDs don't have /proc, but they provide a nice substitute */
 443     struct kinfo_proc *proc = kinfo_getproc(pid);
 444
 445     if (proc) {
 446         name = g_strdup(proc->ki_comm);
 447         free(proc);
 448     }
 449 #else
 450     /* Assume a system with reasonable procfs */
 451     char *pid_path;
 452     size_t len;
 453
 454     pid_path = g_strdup_printf("/proc/%d/cmdline", pid);
 455     g_file_get_contents(pid_path, &name, &len, NULL);
 456     g_free(pid_path);
 457 #endif
 458
 459     return name;
 460 }
 461
 462
 463 pid_t qemu_fork(Error **errp)
 464 {
 465     sigset_t oldmask, newmask;
 466     struct sigaction sig_action;
 467     int saved_errno;
 468     pid_t pid;
 469
 470     /*
 471      * Need to block signals now, so that child process can safely
 472      * kill off caller's signal handlers without a race.
 473      */
 474     sigfillset(&newmask);
 475     if (pthread_sigmask(SIG_SETMASK, &newmask, &oldmask) != 0) {
 476         error_setg_errno(errp, errno,
 477                          "cannot block signals");
 478         return -1;
 479     }
 480
 481     pid = fork();
 482     saved_errno = errno;
 483
 484     if (pid < 0) {
 485         /* attempt to restore signal mask, but ignore failure, to
 486          * avoid obscuring the fork failure */
 487         (void)pthread_sigmask(SIG_SETMASK, &oldmask, NULL);
 488         error_setg_errno(errp, saved_errno,
 489                          "cannot fork child process");
 490         errno = saved_errno;
 491         return -1;
 492     } else if (pid) {
 493         /* parent process */
 494
 495         /* Restore our original signal mask now that the child is
 496          * safely running. Only documented failures are EFAULT (not
 497          * possible, since we are using just-grabbed mask) or EINVAL
 498          * (not possible, since we are using correct arguments).  */
 499         (void)pthread_sigmask(SIG_SETMASK, &oldmask, NULL);
 500     } else {
 501         /* child process */
 502         size_t i;
 503
 504         /* Clear out all signal handlers from parent so nothing
 505          * unexpected can happen in our child once we unblock
 506          * signals */
 507         sig_action.sa_handler = SIG_DFL;
 508         sig_action.sa_flags = 0;
 509         sigemptyset(&sig_action.sa_mask);
 510
 511         for (i = 1; i < NSIG; i++) {
 512             /* Only possible errors are EFAULT or EINVAL The former
 513              * won't happen, the latter we expect, so no need to check
 514              * return value */
 515             (void)sigaction(i, &sig_action, NULL);
 516         }
 517
 518         /* Unmask all signals in child, since we've no idea what the
 519          * caller's done with their signal mask and don't want to
 520          * propagate that to children */
 521         sigemptyset(&newmask);
 522         if (pthread_sigmask(SIG_SETMASK, &newmask, NULL) != 0) {
 523             Error *local_err = NULL;
 524             error_setg_errno(&local_err, errno,
 525                              "cannot unblock signals");
 526             error_report_err(local_err);
 527             _exit(1);
 528         }
 529     }
 530     return pid;
 531 }
 532
 533 void *qemu_alloc_stack(size_t *sz)
 534 {
 535     void *ptr, *guardpage;
 536 #ifdef CONFIG_DEBUG_STACK_USAGE
 537     void *ptr2;
 538 #endif
 539     size_t pagesz = getpagesize();
 540 #ifdef _SC_THREAD_STACK_MIN
 541     /* avoid stacks smaller than _SC_THREAD_STACK_MIN */
 542     long min_stack_sz = sysconf(_SC_THREAD_STACK_MIN);
 543     *sz = MAX(MAX(min_stack_sz, 0), *sz);
 544 #endif
 545     /* adjust stack size to a multiple of the page size */
 546     *sz = ROUND_UP(*sz, pagesz);
 547     /* allocate one extra page for the guard page */
 548     *sz += pagesz;
 549
 550     ptr = mmap(NULL, *sz, PROT_READ | PROT_WRITE,
 551                MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 552     if (ptr == MAP_FAILED) {
 553         abort();
 554     }
 555
 556 #if defined(HOST_IA64)
 557     /* separate register stack */
 558     guardpage = ptr + (((*sz - pagesz) / 2) & ~pagesz);
 559 #elif defined(HOST_HPPA)
 560     /* stack grows up */
 561     guardpage = ptr + *sz - pagesz;
 562 #else
 563     /* stack grows down */
 564     guardpage = ptr;
 565 #endif
 566     if (mprotect(guardpage, pagesz, PROT_NONE) != 0) {
 567         abort();
 568     }
 569
 570 #ifdef CONFIG_DEBUG_STACK_USAGE
 571     for (ptr2 = ptr + pagesz; ptr2 < ptr + *sz; ptr2 += sizeof(uint32_t)) {
 572         *(uint32_t *)ptr2 = 0xdeadbeaf;
 573     }
 574 #endif
 575
 576     return ptr;
 577 }
 578
 579 #ifdef CONFIG_DEBUG_STACK_USAGE
 580 static __thread unsigned int max_stack_usage;
 581 #endif
 582
 583 void qemu_free_stack(void *stack, size_t sz)
 584 {
 585 #ifdef CONFIG_DEBUG_STACK_USAGE
 586     unsigned int usage;
 587     void *ptr;
 588
 589     for (ptr = stack + getpagesize(); ptr < stack + sz;
 590          ptr += sizeof(uint32_t)) {
 591         if (*(uint32_t *)ptr != 0xdeadbeaf) {
 592             break;
 593         }
 594     }
 595     usage = sz - (uintptr_t) (ptr - stack);
 596     if (usage > max_stack_usage) {
 597         error_report("thread %d max stack usage increased from %u to %u",
 598                      qemu_get_thread_id(), max_stack_usage, usage);
 599         max_stack_usage = usage;
 600     }
 601 #endif
 602
 603     munmap(stack, sz);
 604 }