src/runtime/bsd-os.c

   1 /*
   2  * OS-dependent routines for BSD-ish systems
   3  *
   4  * This file (along with os.h) exports an OS-independent interface to
   5  * the operating system VM facilities. This interface looks a lot like
   6  * the Mach interface (but simpler in some places). For some operating
   7  * systems, a subset of these functions will have to be emulated.
   8  */
   9
  10 /*
  11  * This software is part of the SBCL system. See the README file for
  12  * more information.
  13  *
  14  * This software is derived from the CMU CL system, which was
  15  * written at Carnegie Mellon University and released into the
  16  * public domain. The software is in the public domain and is
  17  * provided with absolutely no warranty. See the COPYING and CREDITS
  18  * files for more information.
  19  */
  20
  21 #include <stdio.h>
  22 #include <sys/param.h>
  23 #include <sys/file.h>
  24 #include <unistd.h>
  25 #include <utime.h>
  26 #include <assert.h>
  27 #include <errno.h>
  28 #include "sbcl.h"
  29 #include "./signal.h"
  30 #include "os.h"
  31 #include "arch.h"
  32 #include "globals.h"
  33 #include "interrupt.h"
  34 #include "interr.h"
  35 #include "lispregs.h"
  36 #include "thread.h"
  37 #include "runtime.h"
  38 #include "genesis/static-symbols.h"
  39 #include "genesis/fdefn.h"
  40
  41 #include <sys/types.h>
  42 #include <signal.h>
  43 /* #include <sys/sysinfo.h> */
  44 #include "validate.h"
  45 #if defined LISP_FEATURE_GENCGC
  46 #include "gencgc-internal.h"
  47 #endif
  48
  49 #if defined(LISP_FEATURE_SB_WTIMER) && !defined(LISP_FEATURE_DARWIN)
  50 # include <sys/event.h>
  51 #endif
  52
  53 \f
  54 os_vm_size_t os_vm_page_size;
  55
  56 #ifdef __NetBSD__
  57 #include <sys/resource.h>
  58 #include <sys/sysctl.h>
  59 #include <string.h>
  60 #include <sys/stat.h> /* For the stat-family wrappers. */
  61 #include <dirent.h>   /* For the opendir()/readdir() wrappers */
  62 #include <sys/socket.h> /* For the socket() wrapper */
  63 static void netbsd_init();
  64 static os_vm_size_t max_allocation_size;
  65 #endif /* __NetBSD__ */
  66
  67 #if defined LISP_FEATURE_FREEBSD
  68 #include <sys/sysctl.h>
  69 #if defined(LISP_FEATURE_SB_THREAD) && !defined(LISP_FEATURE_SB_PTHREAD_FUTEX)
  70 #include <sys/umtx.h>
  71 #endif
  72
  73 static void freebsd_init();
  74 #endif /* __FreeBSD__ */
  75
  76 #ifdef __DragonFly__
  77 #include <sys/sysctl.h>
  78
  79 static void dragonfly_init();
  80 #endif /* __DragonFly__ */
  81
  82 #ifdef __OpenBSD__
  83 #include <sys/types.h>
  84 #include <sys/resource.h>
  85 #include <sys/stat.h>
  86 #include <sys/sysctl.h>
  87 #include <dlfcn.h>
  88 #ifdef LISP_FEATURE_X86
  89 #include <machine/cpu.h>
  90 #endif
  91
  92 static void openbsd_init();
  93 #endif
  94
  95 void
  96 os_init(char *argv[], char *envp[])
  97 {
  98     os_vm_page_size = BACKEND_PAGE_BYTES;
  99
 100 #ifdef __NetBSD__
 101     netbsd_init();
 102 #elif defined(LISP_FEATURE_FREEBSD)
 103     freebsd_init();
 104 #elif defined(__OpenBSD__)
 105     openbsd_init();
 106 #elif defined(LISP_FEATURE_DARWIN)
 107     darwin_init();
 108 #elif defined(__DragonFly__)
 109     dragonfly_init();
 110 #endif
 111 }
 112
 113 sigset_t *
 114 os_context_sigmask_addr(os_context_t *context)
 115 {
 116     /* (Unlike most of the other context fields that we access, the
 117      * signal mask field is a field of the basic, outermost context
 118      * struct itself both in FreeBSD 4.0 and in OpenBSD 2.6.) */
 119 #if defined(LISP_FEATURE_FREEBSD) || defined(__NetBSD__) || defined(LISP_FEATURE_DARWIN) \
 120     || defined(__DragonFly__)
 121     return &context->uc_sigmask;
 122 #elif defined (__OpenBSD__)
 123     return &context->sc_mask;
 124 #else
 125 #error unsupported BSD variant
 126 #endif
 127 }
 128
 129 os_vm_address_t
 130 os_validate(os_vm_address_t addr, os_vm_size_t len)
 131 {
 132     int flags = MAP_PRIVATE | MAP_ANON;
 133
 134     if (addr)
 135         flags |= MAP_FIXED;
 136
 137 #ifdef __NetBSD__
 138     if (addr) {
 139         os_vm_address_t curaddr = addr;
 140
 141         while (len > 0) {
 142             os_vm_address_t resaddr;
 143             os_vm_size_t curlen = MIN(max_allocation_size, len);
 144
 145             resaddr = mmap(curaddr, curlen, OS_VM_PROT_ALL, flags, -1, 0);
 146
 147             if (resaddr == (os_vm_address_t) - 1) {
 148                 perror("mmap");
 149
 150                 while (curaddr > addr) {
 151                     curaddr -= max_allocation_size;
 152                     munmap(curaddr, max_allocation_size);
 153                 }
 154
 155                 return NULL;
 156             }
 157
 158             curaddr += curlen;
 159             len -= curlen;
 160         }
 161     } else
 162 #endif
 163     {
 164         addr = mmap(addr, len, OS_VM_PROT_ALL, flags, -1, 0);
 165     }
 166
 167     if (addr == MAP_FAILED) {
 168         perror("mmap");
 169         return NULL;
 170     }
 171
 172     return addr;
 173 }
 174
 175 void
 176 os_invalidate(os_vm_address_t addr, os_vm_size_t len)
 177 {
 178     if (munmap(addr, len) == -1)
 179         perror("munmap");
 180 }
 181
 182 os_vm_address_t
 183 os_map(int fd, int offset, os_vm_address_t addr, os_vm_size_t len)
 184 {
 185     addr = mmap(addr, len,
 186                 OS_VM_PROT_ALL,
 187                 MAP_PRIVATE | MAP_FILE | MAP_FIXED,
 188                 fd, (off_t) offset);
 189
 190     if (addr == MAP_FAILED) {
 191         perror("mmap");
 192         lose("unexpected mmap(..) failure\n");
 193     }
 194
 195     return addr;
 196 }
 197
 198 void
 199 os_protect(os_vm_address_t address, os_vm_size_t length, os_vm_prot_t prot)
 200 {
 201     if (mprotect(address, length, prot) == -1) {
 202         perror("mprotect");
 203     }
 204 }
 205 \f
 206 static boolean
 207 in_range_p(os_vm_address_t a, lispobj sbeg, size_t slen)
 208 {
 209     char* beg = (char*) sbeg;
 210     char* end = (char*) sbeg + slen;
 211     char* adr = (char*) a;
 212     return (adr >= beg && adr < end);
 213 }
 214
 215 boolean
 216 is_valid_lisp_addr(os_vm_address_t addr)
 217 {
 218     struct thread *th;
 219
 220     if (in_range_p(addr, READ_ONLY_SPACE_START, READ_ONLY_SPACE_SIZE) ||
 221         in_range_p(addr, STATIC_SPACE_START, STATIC_SPACE_SIZE) ||
 222         in_range_p(addr, DYNAMIC_SPACE_START, dynamic_space_size))
 223         return 1;
 224     for_each_thread(th) {
 225         if (((os_vm_address_t)th->control_stack_start <= addr) &&
 226             (addr < (os_vm_address_t)th->control_stack_end))
 227             return 1;
 228         if (in_range_p(addr, (lispobj) th->binding_stack_start,
 229                        BINDING_STACK_SIZE))
 230             return 1;
 231     }
 232     return 0;
 233 }
 234 \f
 235 /*
 236  * any OS-dependent special low-level handling for signals
 237  */
 238
 239 #if defined LISP_FEATURE_GENCGC
 240
 241 /*
 242  * The GENCGC needs to be hooked into whatever signal is raised for
 243  * page fault on this OS.
 244  */
 245
 246 void
 247 memory_fault_handler(int signal, siginfo_t *siginfo, os_context_t *context)
 248 {
 249     void *fault_addr = arch_get_bad_addr(signal, siginfo, context);
 250
 251 #if defined(LISP_FEATURE_RESTORE_TLS_SEGMENT_REGISTER_FROM_CONTEXT)
 252     FSHOW_SIGNAL((stderr, "/ TLS: restoring fs: %p in memory_fault_handler\n",
 253                   *CONTEXT_ADDR_FROM_STEM(fs)));
 254     os_restore_tls_segment_register(context);
 255 #endif
 256
 257     FSHOW((stderr, "Memory fault at: %p, PC: %p\n", fault_addr, *os_context_pc_addr(context)));
 258
 259 #ifdef LISP_FEATURE_SB_SAFEPOINT
 260     if (!handle_safepoint_violation(context, fault_addr))
 261 #endif
 262
 263     if (!gencgc_handle_wp_violation(fault_addr))
 264         if(!handle_guard_page_triggered(context,fault_addr))
 265             lisp_memory_fault_error(context, fault_addr);
 266 }
 267
 268 #if defined(LISP_FEATURE_MACH_EXCEPTION_HANDLER)
 269 void
 270 mach_error_memory_fault_handler(int signal, siginfo_t *siginfo,
 271                                 os_context_t *context) {
 272     lose("Unhandled memory fault. Exiting.");
 273 }
 274 #endif
 275
 276 void
 277 os_install_interrupt_handlers(void)
 278 {
 279     SHOW("os_install_interrupt_handlers()/bsd-os/defined(GENCGC)");
 280 #if defined(LISP_FEATURE_MACH_EXCEPTION_HANDLER)
 281     undoably_install_low_level_interrupt_handler(SIG_MEMORY_FAULT,
 282                                                  mach_error_memory_fault_handler);
 283 #else
 284     undoably_install_low_level_interrupt_handler(SIG_MEMORY_FAULT,
 285 #if defined(LISP_FEATURE_FREEBSD) && !defined(__GLIBC__)
 286                                                  (__siginfohandler_t *)
 287 #endif
 288                                                  memory_fault_handler);
 289 #endif
 290
 291 #ifdef LISP_FEATURE_SB_THREAD
 292 # ifdef LISP_FEATURE_SB_SAFEPOINT
 293 #  ifdef LISP_FEATURE_SB_THRUPTION
 294     undoably_install_low_level_interrupt_handler(SIGPIPE, thruption_handler);
 295 #  endif
 296 # else
 297     undoably_install_low_level_interrupt_handler(SIG_STOP_FOR_GC,
 298                                                  sig_stop_for_gc_handler);
 299 # endif
 300 #endif
 301     SHOW("leaving os_install_interrupt_handlers()");
 302 }
 303
 304 #else /* Currently PPC/Darwin/Cheney only */
 305
 306 static void
 307 sigsegv_handler(int signal, siginfo_t *info, os_context_t *context)
 308 {
 309     os_vm_address_t addr;
 310
 311     addr = arch_get_bad_addr(signal, info, context);
 312     if (!cheneygc_handle_wp_violation(context, addr))
 313         if (!handle_guard_page_triggered(context, addr))
 314             interrupt_handle_now(signal, info, context);
 315 }
 316
 317 void
 318 os_install_interrupt_handlers(void)
 319 {
 320     SHOW("os_install_interrupt_handlers()/bsd-os/!defined(GENCGC)");
 321     undoably_install_low_level_interrupt_handler(SIG_MEMORY_FAULT,
 322                                                  sigsegv_handler);
 323 }
 324
 325 #endif /* defined GENCGC */
 326
 327 #ifdef __NetBSD__
 328 static void netbsd_init()
 329 {
 330     struct rlimit rl;
 331     int mib[2], osrev;
 332     size_t len;
 333
 334     /* Are we running on a sufficiently functional kernel? */
 335     mib[0] = CTL_KERN;
 336     mib[1] = KERN_OSREV;
 337
 338     len = sizeof(osrev);
 339     sysctl(mib, 2, &osrev, &len, NULL, 0);
 340
 341     /* If we're older than 2.0... */
 342     if (osrev < 200000000) {
 343         fprintf(stderr, "osrev = %d (needed at least 200000000).\n", osrev);
 344         lose("NetBSD kernel too old to run sbcl.\n");
 345     }
 346
 347     /* NetBSD counts mmap()ed space against the process's data size limit,
 348      * so yank it up. This might be a nasty thing to do? */
 349     getrlimit (RLIMIT_DATA, &rl);
 350     if (rl.rlim_cur < rl.rlim_max) {
 351         rl.rlim_cur = rl.rlim_max;
 352         if (setrlimit (RLIMIT_DATA, &rl) < 0) {
 353             fprintf (stderr,
 354                      "RUNTIME WARNING: unable to raise process data size limit:\n\
 355 %s.\n\
 356 The system may fail to start.\n",
 357                      strerror(errno));
 358         }
 359     }
 360     max_allocation_size = (os_vm_size_t)((rl.rlim_cur / 2) &
 361       ~(32 * 1024 * 1024));
 362
 363 #ifdef LISP_FEATURE_X86
 364     {
 365         size_t len;
 366         int sse;
 367
 368         len = sizeof(sse);
 369         if (sysctlbyname("machdep.sse", &sse, &len,
 370                          NULL, 0) == 0 && sse != 0) {
 371             /* Use the SSE detector */
 372             fast_bzero_pointer = fast_bzero_detect;
 373         }
 374      }
 375 #endif /* LISP_FEATURE_X86 */
 376 }
 377
 378 /* Various routines in NetBSD's C library are compatibility wrappers
 379    for old versions. Programs must be processed by the C toolchain in
 380    order to get up-to-date definitions of such routines. */
 381 /* The stat-family, opendir, and readdir are used only in sb-posix, as
 382    of 2007-01-16. -- RMK */
 383 int
 384 _stat(const char *path, struct stat *sb)
 385 {
 386     return stat(path, sb);
 387 }
 388 int
 389 _lstat(const char *path, struct stat *sb)
 390 {
 391     return lstat(path, sb);
 392 }
 393 int
 394 _fstat(int fd, struct stat *sb)
 395 {
 396     return fstat(fd, sb);
 397 }
 398
 399 DIR *
 400 _opendir(const char *filename)
 401 {
 402     return opendir(filename);
 403 }
 404 struct dirent *
 405 _readdir(DIR *dirp)
 406 {
 407     return readdir(dirp);
 408 }
 409
 410 int
 411 _utime(const char *file, const struct utimbuf *timep)
 412 {
 413     return utime(file, timep);
 414 }
 415
 416 /* Used in sb-bsd-sockets. */
 417 int
 418 _socket(int domain, int type, int protocol)
 419 {
 420     return socket(domain, type, protocol);
 421 }
 422 #endif /* __NetBSD__ */
 423
 424 #if defined(LISP_FEATURE_FREEBSD)
 425 #ifndef __GLIBC__
 426 extern int getosreldate(void);
 427 #endif
 428
 429 int sig_memory_fault;
 430
 431 static void freebsd_init()
 432 {
 433     /* Memory fault signal on FreeBSD was changed from SIGBUS to
 434      * SIGSEGV. */
 435 #ifdef __GLIBC__
 436         sig_memory_fault = SIGSEGV;
 437 #else
 438     if (getosreldate() < 700004)
 439         sig_memory_fault = SIGBUS;
 440     else
 441         sig_memory_fault = SIGSEGV;
 442 #endif
 443
 444     /* Quote from sbcl-devel (NIIMI Satoshi): "Some OSes, like FreeBSD
 445      * 4.x with GENERIC kernel, does not enable SSE support even on
 446      * SSE capable CPUs". Detect this situation and skip the
 447      * fast_bzero sse/base selection logic that's normally done in
 448      * x86-assem.S.
 449      */
 450 #ifdef LISP_FEATURE_X86
 451     {
 452         size_t len;
 453         int instruction_sse;
 454
 455         len = sizeof(instruction_sse);
 456         if (sysctlbyname("hw.instruction_sse", &instruction_sse, &len,
 457                          NULL, 0) == 0 && instruction_sse != 0) {
 458             /* Use the SSE detector */
 459             fast_bzero_pointer = fast_bzero_detect;
 460         }
 461     }
 462 #endif /* LISP_FEATURE_X86 */
 463 }
 464
 465 #if defined(LISP_FEATURE_SB_THREAD) && defined(LISP_FEATURE_SB_FUTEX) \
 466     && !defined(LISP_FEATURE_SB_PTHREAD_FUTEX)
 467 int
 468 futex_wait(int *lock_word, long oldval, long sec, unsigned long usec)
 469 {
 470     struct timespec timeout;
 471     int ret;
 472
 473     if (sec < 0)
 474         ret = umtx_wait((void *)lock_word, oldval, NULL);
 475     else {
 476         timeout.tv_sec = sec;
 477         timeout.tv_nsec = usec * 1000;
 478         ret = umtx_wait((void *)lock_word, oldval, &timeout);
 479     }
 480
 481     switch (ret) {
 482     case 0:
 483         return 0;
 484     case ETIMEDOUT:
 485         return 1;
 486     case EINTR:
 487         return 2;
 488     default:
 489         /* EWOULDBLOCK and others, need to check the lock */
 490         return -1;
 491     }
 492 }
 493
 494 int
 495 futex_wake(int *lock_word, int n)
 496 {
 497     return umtx_wake((void *)lock_word, n);
 498 }
 499 #endif
 500 #endif /* __FreeBSD__ */
 501
 502 #ifdef __DragonFly__
 503 static void dragonfly_init()
 504 {
 505 #ifdef LISP_FEATURE_X86
 506     size_t len;
 507     int instruction_sse;
 508
 509     len = sizeof(instruction_sse);
 510     if (sysctlbyname("hw.instruction_sse", &instruction_sse, &len,
 511                      NULL, 0) == 0 && instruction_sse != 0) {
 512         /* Use the SSE detector */
 513         fast_bzero_pointer = fast_bzero_detect;
 514     }
 515 #endif /* LISP_FEATURE_X86 */
 516 }
 517
 518
 519 #if defined(LISP_FEATURE_SB_THREAD) && defined(LISP_FEATURE_SB_FUTEX) \
 520     && !defined(LISP_FEATURE_SB_PTHREAD_FUTEX)
 521 int
 522 futex_wait(int *lock_word, long oldval, long sec, unsigned long usec)
 523 {
 524     int ret;
 525
 526     if (sec < 0)
 527         ret = umtx_sleep(lock_word, oldval, 0);
 528     else {
 529         int count = usec + 1000000 * sec;
 530         ret = umtx_sleep(lock_word, oldval, count);
 531     }
 532
 533     if (ret == 0) return 0;
 534     else {
 535         switch (errno) {
 536         case EWOULDBLOCK: // Operation timed out
 537             return 1;
 538         case EINTR:
 539             return 2;
 540         default: // Such as EINVAL or EBUSY
 541             return -1;
 542         }
 543     }
 544 }
 545
 546 int
 547 futex_wake(int *lock_word, int n)
 548 {
 549     return umtx_wakeup(lock_word, n);
 550 }
 551 #endif
 552 #endif /* __DragonFly__ */
 553
 554 #ifdef LISP_FEATURE_DARWIN
 555 /* defined in ppc-darwin-os.c instead */
 556 #elif defined(LISP_FEATURE_FREEBSD)
 557 #ifndef KERN_PROC_PATHNAME
 558 #define KERN_PROC_PATHNAME 12
 559 #endif
 560
 561 char *
 562 os_get_runtime_executable_path(int external)
 563 {
 564     char path[PATH_MAX + 1];
 565
 566 #ifndef __GLIBC__
 567     if (getosreldate() >= 600024) {
 568 #endif
 569         /* KERN_PROC_PATHNAME is available */
 570         size_t len = PATH_MAX + 1;
 571         int mib[4];
 572
 573         mib[0] = CTL_KERN;
 574         mib[1] = KERN_PROC;
 575         mib[2] = KERN_PROC_PATHNAME;
 576         mib[3] = -1;
 577         if (sysctl(mib, 4, &path, &len, NULL, 0) != 0)
 578             return NULL;
 579 #ifndef __GLIBC__
 580     } else {
 581         int size;
 582         size = readlink("/proc/curproc/file", path, sizeof(path) - 1);
 583         if (size < 0)
 584             return NULL;
 585         path[size] = '\0';
 586     }
 587 #endif
 588     if (strcmp(path, "unknown") == 0)
 589         return NULL;
 590     return copied_string(path);
 591 }
 592 #elif defined(LISP_FEATURE_DRAGONFLY)
 593 char *
 594 os_get_runtime_executable_path(int external)
 595 {
 596     char path[PATH_MAX + 1];
 597     int size = readlink("/proc/curproc/file", path, sizeof(path) - 1);
 598     if (size < 0)
 599         return NULL;
 600     path[size] = '\0';
 601
 602     if (strcmp(path, "unknown") == 0)
 603         return NULL;
 604     return copied_string(path);
 605 }
 606 #elif defined(LISP_FEATURE_NETBSD) || defined(LISP_FEATURE_OPENBSD)
 607 char *
 608 os_get_runtime_executable_path(int external)
 609 {
 610     struct stat sb;
 611     if (!external && stat("/proc/curproc/file", &sb) == 0)
 612         return copied_string("/proc/curproc/file");
 613     return NULL;
 614 }
 615 #else /* Not DARWIN or FREEBSD or NETBSD or OPENBSD or DragonFly */
 616 char *
 617 os_get_runtime_executable_path(int external)
 618 {
 619     return NULL;
 620 }
 621 #endif
 622
 623 #ifdef __OpenBSD__
 624
 625 int openbsd_use_fxsave = 0;
 626
 627 void
 628 openbsd_init()
 629 {
 630 #ifdef LISP_FEATURE_X86
 631     int mib[2];
 632     size_t size;
 633 #endif
 634     /*
 635      * Show a warning if it looks like the memory available after
 636      * allocating the spaces won't be at least this much.
 637      */
 638 #ifdef LISP_FEATURE_64_BIT
 639     const int wantfree = 64 * 1024 * 1024;
 640 #else
 641     const int wantfree = 32 * 1024 * 1024;
 642 #endif
 643     struct rlimit rl;
 644
 645 #ifdef LISP_FEATURE_X86
 646     /* Save the machdep.osfxsr sysctl for use by os_restore_fp_control() */
 647     mib[0] = CTL_MACHDEP;
 648     mib[1] = CPU_OSFXSR;
 649     size = sizeof (openbsd_use_fxsave);
 650     sysctl(mib, 2, &openbsd_use_fxsave, &size, NULL, 0);
 651 #endif
 652
 653     /* OpenBSD, like NetBSD, counts mmap()ed space against the
 654      * process's data size limit. If the soft limit is lower than the
 655      * hard limit then try to yank it up, this lets users in the
 656      * "staff" or "daemon" login classes run sbcl with larger dynamic
 657      * space sizes.
 658      */
 659     getrlimit (RLIMIT_DATA, &rl);
 660     if (rl.rlim_cur < rl.rlim_max) {
 661         rl.rlim_cur = rl.rlim_max;
 662         if (setrlimit (RLIMIT_DATA, &rl) < 0) {
 663             fprintf (stderr,
 664                      "RUNTIME WARNING: unable to raise process data size limit:\n\
 665   %s.\n\
 666 The system may fail to start.\n",
 667                      strerror(errno));
 668         }
 669     }
 670
 671     /*
 672      * Display a (hopefully) helpful warning if it looks like we won't
 673      * be able to allocate enough memory.
 674      */
 675     getrlimit (RLIMIT_DATA, &rl);
 676     if (dynamic_space_size + READ_ONLY_SPACE_SIZE + STATIC_SPACE_SIZE +
 677         LINKAGE_TABLE_SPACE_SIZE + wantfree > rl.rlim_cur)
 678         fprintf (stderr,
 679                  "RUNTIME WARNING: data size resource limit may be too low,\n"
 680                  "  try decreasing the dynamic space size with --dynamic-space-size\n"
 681                  "  or raising the datasize or datasize-max limits in /etc/login.conf\n");
 682 }
 683
 684 /* OpenBSD's dlsym() relies on the gcc bulitin
 685  * __builtin_return_address(0) returning an address in the
 686  * executable's text segment, but when called from lisp it will return
 687  * an address in the dynamic space.  Work around this by calling this
 688  * wrapper function instead. Note that tail-call optimization will
 689  * defeat this, disable it by saving the dlsym() return value in a
 690  * volatile variable.
 691 */
 692 void *
 693 os_dlsym(void *handle, const char *symbol)
 694 {
 695     void * volatile ret = dlsym(handle, symbol);
 696     return ret;
 697 }
 698
 699 #endif
 700
 701 #if defined(LISP_FEATURE_SB_WTIMER) && !defined(LISP_FEATURE_DARWIN)
 702 /*
 703  * Waitable timer implementation for the safepoint-based (SIGALRM-free)
 704  * timer facility using kqueue.
 705  */
 706 int
 707 os_create_wtimer()
 708 {
 709     int kq = kqueue();
 710     if (kq == -1)
 711         lose("os_create_wtimer: kqueue");
 712     return kq;
 713 }
 714
 715 int
 716 os_wait_for_wtimer(int kq)
 717 {
 718     struct kevent ev;
 719     int n;
 720     if ( (n = kevent(kq, 0, 0, &ev, 1, 0)) == -1) {
 721         if (errno != EINTR)
 722             lose("os_wtimer_listen failed");
 723         n = 0;
 724     }
 725     return n != 1;
 726 }
 727
 728 void
 729 os_close_wtimer(int kq)
 730 {
 731     if (close(kq) == -1)
 732         lose("os_close_wtimer failed");
 733 }
 734
 735 void
 736 os_set_wtimer(int kq, int sec, int nsec)
 737 {
 738     long long msec
 739         = ((long long) sec) * 1000 + (long long) (nsec+999999) / 1000000;
 740     if (msec > INT_MAX) msec = INT_MAX;
 741
 742     struct kevent ev;
 743     EV_SET(&ev, 1, EVFILT_TIMER, EV_ADD|EV_ENABLE|EV_ONESHOT, 0, (int)msec, 0);
 744     if (kevent(kq, &ev, 1, 0, 0, 0) == -1)
 745         perror("os_set_wtimer: kevent");
 746 }
 747
 748 void
 749 os_cancel_wtimer(int kq)
 750 {
 751     struct kevent ev;
 752     EV_SET(&ev, 1, EVFILT_TIMER, EV_DISABLE, 0, 0, 0);
 753     if (kevent(kq, &ev, 1, 0, 0, 0) == -1 && errno != ENOENT)
 754         perror("os_cancel_wtimer: kevent");
 755 }
 756 #endif