Add Darwin support

[Torrekie]

• Compiles libepoll-shim.dylib for Darwin systems (macOS/iOS)
• rwlock (semaphore functions not working on Darwin)
• Testsuites (Compiles, but skipped some of them)
• Reimplement kqueue1() since Darwin forced close-on-exec for its file descriptors, I'm not sure if this going to affect epoll functions

[Torrekie]

Now I can confirm this works on macOS/iOS, but testsuites cannot be compiled since it was using many calls that not exist on Darwin(e.g. pipe2() and accept4()), probably needs to rewrite all tests for Darwin

[Torrekie]

Some tests failed, and it stuck at test 23

TorrekiedeMBP:epoll-shim torrekie$ make -C build/ test
make: Entering directory '/Users/torrekie/proj/epoll-shim/build'
Running tests...
Test project /Users/torrekie/proj/epoll-shim/build
        Start   1: epoll-test.epoll__simple
  1/130 Test   #1: epoll-test.epoll__simple ..............................................   Passed    0.03 sec
        Start   2: epoll-test.epoll__poll_flags
  2/130 Test   #2: epoll-test.epoll__poll_flags ..........................................   Passed    0.03 sec
        Start   3: epoll-test.epoll__leakcheck
  3/130 Test   #3: epoll-test.epoll__leakcheck ...........................................   Passed    0.03 sec
        Start   4: epoll-test.epoll__fd_exhaustion
  4/130 Test   #4: epoll-test.epoll__fd_exhaustion .......................................   Passed    0.03 sec
        Start   5: epoll-test.epoll__invalid_op
  5/130 Test   #5: epoll-test.epoll__invalid_op ..........................................   Passed    0.03 sec
        Start   6: epoll-test.epoll__invalid_op2
  6/130 Test   #6: epoll-test.epoll__invalid_op2 .........................................   Passed    0.03 sec
        Start   7: epoll-test.epoll__simple_wait
  7/130 Test   #7: epoll-test.epoll__simple_wait .........................................   Passed    0.03 sec
        Start   8: epoll-test.epoll__event_size
  8/130 Test   #8: epoll-test.epoll__event_size ..........................................***Failed    0.03 sec
        Start   9: epoll-test.epoll__recursive_register
  9/130 Test   #9: epoll-test.epoll__recursive_register ..................................   Passed    0.04 sec
        Start  10: epoll-test.epoll__simple_epollin
 10/130 Test  #10: epoll-test.epoll__simple_epollin ......................................   Passed    0.04 sec
        Start  11: epoll-test.epoll__sleep_argument
 11/130 Test  #11: epoll-test.epoll__sleep_argument ......................................   Passed    0.26 sec
        Start  12: epoll-test.epoll__remove_nonexistent
 12/130 Test  #12: epoll-test.epoll__remove_nonexistent ..................................   Passed    0.05 sec
        Start  13: epoll-test.epoll__add_remove
 13/130 Test  #13: epoll-test.epoll__add_remove ..........................................   Passed    0.03 sec
        Start  14: epoll-test.epoll__add_existing
 14/130 Test  #14: epoll-test.epoll__add_existing ........................................   Passed    0.03 sec
        Start  15: epoll-test.epoll__modify_existing
 15/130 Test  #15: epoll-test.epoll__modify_existing .....................................   Passed    0.09 sec
        Start  16: epoll-test.epoll__modify_nonexisting
 16/130 Test  #16: epoll-test.epoll__modify_nonexisting ..................................   Passed    0.02 sec
        Start  17: epoll-test.epoll__poll_only_fd
 17/130 Test  #17: epoll-test.epoll__poll_only_fd ........................................***Failed    0.03 sec
        Start  18: epoll-test.epoll__no_epollin_on_closed_empty_pipe
 18/130 Test  #18: epoll-test.epoll__no_epollin_on_closed_empty_pipe .....................   Passed    0.03 sec
        Start  19: epoll-test.epoll__write_to_pipe_until_full
 19/130 Test  #19: epoll-test.epoll__write_to_pipe_until_full ............................   Passed    0.35 sec
        Start  20: epoll-test.epoll__realtime_timer
 20/130 Test  #20: epoll-test.epoll__realtime_timer ......................................   Passed    1.27 sec
        Start  21: epoll-test.epoll__simple_signalfd
 21/130 Test  #21: epoll-test.epoll__simple_signalfd .....................................   Passed    0.05 sec
        Start  22: epoll-test.epoll__signalfd_poll_sigusr1
 22/130 Test  #22: epoll-test.epoll__signalfd_poll_sigusr1 ...............................***Failed    0.03 sec
        Start  23: epoll-test.epoll__signalfd_in_thread

^Cmake: *** [Makefile:71: test] Interrupt: 2

The implementations of ppoll and sigtimedwait might not quite working as expected

[Torrekie]

I think I need some help on this, I have made tests compile, but many of them failed, I'm not sure which part causing problems
For macOS 11.2.3 arm64:

73% tests passed, 71 tests failed out of 263

Total Test time (real) =  72.77 sec

The following tests did not run:
         25 - epoll-test.epoll__epollhup_on_fresh_socket (Skipped)
         67 - epoll-test-interpose.epoll__epollhup_on_fresh_socket (Skipped)
         85 - timerfd-test.timerfd__many_timers (Skipped)
        104 - timerfd-test-interpose.timerfd__many_timers (Skipped)
        123 - timerfd-root-test.timerfd_root__zero_read_on_abs_realtime (Skipped)
        124 - timerfd-root-test.timerfd_root__read_on_abs_realtime_no_interval (Skipped)
        125 - timerfd-root-test.timerfd_root__cancel_on_set (Skipped)
        126 - timerfd-root-test.timerfd_root__cancel_on_set_init (Skipped)
        127 - timerfd-root-test.timerfd_root__clock_change_notification (Skipped)
        128 - timerfd-root-test.timerfd_root__advance_time_no_cancel (Skipped)
        129 - timerfd-root-test-interpose.timerfd_root__zero_read_on_abs_realtime (Skipped)
        130 - timerfd-root-test-interpose.timerfd_root__read_on_abs_realtime_no_interval (Skipped)
        131 - timerfd-root-test-interpose.timerfd_root__cancel_on_set (Skipped)
        132 - timerfd-root-test-interpose.timerfd_root__cancel_on_set_init (Skipped)
        133 - timerfd-root-test-interpose.timerfd_root__clock_change_notification (Skipped)
        134 - timerfd-root-test-interpose.timerfd_root__advance_time_no_cancel (Skipped)
        135 - timerfd-mock-test.timerfd_mock__mocked_kevent (Skipped)
        136 - timerfd-mock-test-interpose.timerfd_mock__mocked_kevent (Skipped)
        145 - signalfd-test.signalfd__sigwait_openbsd (Skipped)
        146 - signalfd-test.signalfd__sigchld (Skipped)
        156 - signalfd-test-interpose.signalfd__sigwait_openbsd (Skipped)
        157 - signalfd-test-interpose.signalfd__sigchld (Skipped)
        159 - perf-many-fds.perf_many_fds__perf (Skipped)
        160 - perf-many-fds-interpose.perf_many_fds__perf (Skipped)
        173 - eventfd-ctx-test.eventfd__pollout (Skipped)
        180 - eventfd-ctx-test.eventfd__fork (Skipped)
        183 - eventfd-ctx-test.eventfd__epoll (Skipped)
        187 - eventfd-ctx-test-interpose.eventfd__pollout (Skipped)
        194 - eventfd-ctx-test-interpose.eventfd__fork (Skipped)
        197 - eventfd-ctx-test-interpose.eventfd__epoll (Skipped)
        200 - pipe-test.pipe__poll_write_end_after_read_end_close (Skipped)
        205 - pipe-test.pipe__poll_full_minus_512b_write_end_after_read_end_close (Skipped)
        213 - pipe-test.pipe__closed_read_end_of_duplex (Skipped)
        218 - pipe-test-interpose.pipe__poll_write_end_after_read_end_close (Skipped)
        223 - pipe-test-interpose.pipe__poll_full_minus_512b_write_end_after_read_end_close (Skipped)
        231 - pipe-test-interpose.pipe__closed_read_end_of_duplex (Skipped)

The following tests FAILED:
          8 - epoll-test.epoll__event_size (Failed)
         17 - epoll-test.epoll__poll_only_fd (Failed)
         22 - epoll-test.epoll__signalfd_poll_sigusr1 (Failed)
         23 - epoll-test.epoll__signalfd_in_thread (Failed)
         27 - epoll-test.epoll__epollpri (Failed)
         28 - epoll-test.epoll__epollpri_oobinline (Failed)
         29 - epoll-test.epoll__epollpri_oobinline_lt (Failed)
         40 - epoll-test.epoll__epoll_pwait (Failed)
         41 - epoll-test.epoll__cloexec (Failed)
         50 - epoll-test-interpose.epoll__event_size (Failed)
         59 - epoll-test-interpose.epoll__poll_only_fd (Failed)
         64 - epoll-test-interpose.epoll__signalfd_poll_sigusr1 (Failed)
         65 - epoll-test-interpose.epoll__signalfd_in_thread (Failed)
         69 - epoll-test-interpose.epoll__epollpri (Failed)
         70 - epoll-test-interpose.epoll__epollpri_oobinline (Failed)
         71 - epoll-test-interpose.epoll__epollpri_oobinline_lt (Failed)
         82 - epoll-test-interpose.epoll__epoll_pwait (Failed)
         83 - epoll-test-interpose.epoll__cloexec (Failed)
         86 - timerfd-test.timerfd__simple_timer (Failed)
         87 - timerfd-test.timerfd__simple_periodic_timer (Failed)
         88 - timerfd-test.timerfd__complex_periodic_timer (Failed)
         89 - timerfd-test.timerfd__reset_periodic_timer (Failed)
         90 - timerfd-test.timerfd__reenable_periodic_timer (Failed)
         91 - timerfd-test.timerfd__expire_five (Failed)
         95 - timerfd-test.timerfd__upgrade_simple_to_complex (Failed)
         96 - timerfd-test.timerfd__absolute_timer (Failed)
        101 - timerfd-test.timerfd__short_evfilt_timer_timeout (Failed)
        102 - timerfd-test.timerfd__unmodified_errno (Failed)
        105 - timerfd-test-interpose.timerfd__simple_timer (Failed)
        106 - timerfd-test-interpose.timerfd__simple_periodic_timer (Failed)
        107 - timerfd-test-interpose.timerfd__complex_periodic_timer (Failed)
        108 - timerfd-test-interpose.timerfd__reset_periodic_timer (Failed)
        109 - timerfd-test-interpose.timerfd__reenable_periodic_timer (Failed)
        110 - timerfd-test-interpose.timerfd__expire_five (Failed)
        114 - timerfd-test-interpose.timerfd__upgrade_simple_to_complex (Failed)
        115 - timerfd-test-interpose.timerfd__absolute_timer (Failed)
        120 - timerfd-test-interpose.timerfd__short_evfilt_timer_timeout (Failed)
        121 - timerfd-test-interpose.timerfd__unmodified_errno (Failed)
        137 - signalfd-test.signalfd__simple_signalfd (Failed)
        140 - signalfd-test.signalfd__multiple_signals (Failed)
        144 - signalfd-test.signalfd__sigwaitinfo (Failed)
        148 - signalfd-test-interpose.signalfd__simple_signalfd (Failed)
        151 - signalfd-test-interpose.signalfd__multiple_signals (Failed)
        155 - signalfd-test-interpose.signalfd__sigwaitinfo (Failed)
        193 - eventfd-ctx-test-interpose.eventfd__threads_read (Failed)
        202 - pipe-test.pipe__poll_full_write_end_after_read_end_close_hup (Failed)
        206 - pipe-test.pipe__pipe_event_poll (Failed)
        207 - pipe-test.pipe__fifo_writes (Failed)
        208 - pipe-test.pipe__fifo_connecting_reader (Failed)
        209 - pipe-test.pipe__fifo_reads (Failed)
        210 - pipe-test.pipe__fifo_read_eof_wakeups (Failed)
        211 - pipe-test.pipe__fifo_read_eof_state_when_reconnecting (Failed)
        212 - pipe-test.pipe__closed_read_end (Failed)
        214 - pipe-test.pipe__closed_read_end_register_before_close (Failed)
        215 - pipe-test.pipe__closed_write_end (Failed)
        216 - pipe-test.pipe__closed_write_end_register_before_close (Failed)
        220 - pipe-test-interpose.pipe__poll_full_write_end_after_read_end_close_hup (Failed)
        224 - pipe-test-interpose.pipe__pipe_event_poll (Failed)
        225 - pipe-test-interpose.pipe__fifo_writes (Failed)
        226 - pipe-test-interpose.pipe__fifo_connecting_reader (Failed)
        227 - pipe-test-interpose.pipe__fifo_reads (Failed)
        228 - pipe-test-interpose.pipe__fifo_read_eof_wakeups (Failed)
        229 - pipe-test-interpose.pipe__fifo_read_eof_state_when_reconnecting (Failed)
        230 - pipe-test-interpose.pipe__closed_read_end (Failed)
        232 - pipe-test-interpose.pipe__closed_read_end_register_before_close (Failed)
        233 - pipe-test-interpose.pipe__closed_write_end (Failed)
        234 - pipe-test-interpose.pipe__closed_write_end_register_before_close (Failed)
        236 - socketpair-test.socketpair__simple_edge_triggering (Failed)
        240 - socketpair-test-interpose.socketpair__simple_edge_triggering (Failed)
        252 - tst-epoll.epollfd_osv__epoll_file (Failed)
        255 - tst-epoll-interpose.epollfd_osv__epoll_file (Failed)
Errors while running CTest

[jiixyj]

Thanks for you work on this! I actually tried to port this library to macOS last year, but I was discouraged by macOS' poor support for recent (and not so recent) POSIX features, and the fact that it's a bit hard for me to test this. I noticed I hadn't pushed this work yet (shame on me), but now I rebased my old branch and pushed it into the macos branch. I'll have a look at your branch, and try to merge our work.

Back then I got the EVFILT_EXCEPT stuff working and all the tests, at least on x64 macOS. By "working" I mean I had to skip a lot of them, sadly.

I think we should also look at getting a CI build for macOS running, at least for x64. GitHub Actions should support this.

[Torrekie]

shall I rebase my current darwin branch and do pr on your macos branch?

[jiixyj]

shall I rebase my current darwin branch and do pr on your macos branch?

Yes, that would be great!

[Torrekie]

Some tests skipped due to different behavior with kevent(), then I found the struct kevent was different between Darwin and other BSDs

#ifdef __NetBSD__
struct kevent {
        uintptr_t       ident;          /* identifier for this event */
        uint32_t        filter;         /* filter for event */
        uint32_t        flags;          /* action flags for kqueue */
        uint32_t        fflags;         /* filter flag value */
        int64_t         data;           /* filter data value */
        intptr_t        udata;          /* opaque user data identifier */
};
#elif defined(__APPLE__)
struct kevent {
        uintptr_t       ident;  /* identifier for this event */
        int16_t         filter; /* filter for event */
        uint16_t        flags;  /* general flags */
        uint32_t        fflags; /* filter-specific flags */
        intptr_t        data;   /* filter-specific data */
        void            *udata; /* opaque user data identifier */
};
#endif

Consider switch to kevent64 on Darwin

// In <sys/event.h>
struct kevent64_s {
        uint64_t        ident;          /* identifier for this event */
        int16_t         filter;         /* filter for event */
        uint16_t        flags;          /* general flags */
        uint32_t        fflags;         /* filter-specific flags */
        int64_t         data;           /* filter-specific data */
        uint64_t        udata;          /* opaque user data identifier */
        uint64_t        ext[2];         /* filter-specific extensions */
};

#define EV_SET64(kevp, a, b, c, d, e, f, g, h) do {     \
        struct kevent64_s *__kevp__ = (kevp);           \
        __kevp__->ident = (a);                          \
        __kevp__->filter = (b);                         \
        __kevp__->flags = (c);                          \
        __kevp__->fflags = (d);                         \
        __kevp__->data = (e);                           \
        __kevp__->udata = (f);                          \
        __kevp__->ext[0] = (g);                         \
        __kevp__->ext[1] = (h);                         \
} while(0)

int     kevent64(int kq,
    const struct kevent64_s *changelist, int nchanges,
    struct kevent64_s *eventlist, int nevents,
    unsigned int flags,
    const struct timespec *timeout);

[Torrekie]

Seems nothing to change for now except some skipped tests

[wegank]

Putting the definition of itimerspec in <sys/timerfd.h> causes build problems in PipeWire. I think it really should be defined elsewhere.

[Torrekie]

then we probably have to create a sys/time.h like that

#ifndef _LIBEPOLL_SHIM_SYS_TIME_H_
#define _LIBEPOLL_SHIM_SYS_TIME_H_
#include_next <sys/time.h>

#if __APPLE__
struct itimerspec {
	struct timespec it_interval;
	struct timespec it_value;
};
#endif // __APPLE__

#endif // _LIBEPOLL_SHIM_SYS_TIME_H_