Introduce sigtimedwait() on Windows

2025-06-28 07:18:30 +00:00 · 2024-09-14 20:32:46 -07:00 · 2024-09-14 20:32:46 -07:00 · c260144843
commit c260144843
parent 37e2660c7f
17 changed files with 280 additions and 130 deletions
--- a/libc/calls/sigtimedwait-nt.c
+++ b/libc/calls/sigtimedwait-nt.c
@ -0,0 +1,113 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8                               :vi │
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2024 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/calls.h"
+#include "libc/calls/internal.h"
+#include "libc/calls/sig.internal.h"
+#include "libc/calls/struct/siginfo.h"
+#include "libc/calls/struct/sigset.internal.h"
+#include "libc/calls/struct/timespec.internal.h"
+#include "libc/calls/syscall_support-nt.internal.h"
+#include "libc/intrin/atomic.h"
+#include "libc/macros.h"
+#include "libc/nt/runtime.h"
+#include "libc/nt/synchronization.h"
+#include "libc/str/str.h"
+#include "libc/sysv/consts/sicode.h"
+#include "libc/sysv/consts/sig.h"
+#include "libc/sysv/errfuns.h"
+#include "libc/thread/posixthread.internal.h"
+
+textwindows static int sys_sigtimedwait_nt_check(sigset_t syncsigs,
+                                                 siginfo_t *opt_info,
+                                                 sigset_t waitmask) {
+  int sig;
+  if (_check_cancel() == -1)
+    return -1;
+  if ((sig = __sig_get(waitmask))) {
+    if ((1ull << (sig - 1)) & syncsigs) {
+      if (opt_info) {
+        memset(opt_info, 0, sizeof(*opt_info));
+        opt_info->si_signo = sig;
+        opt_info->si_code = SI_TKILL;
+        opt_info->si_uid = sys_getuid_nt();
+      }
+      return sig;
+    }
+    int handler_was_called = __sig_relay(sig, SI_TKILL, waitmask);
+    if (_check_cancel() == -1)
+      return -1;
+    if (handler_was_called)
+      return eintr();
+  }
+  return 0;
+}
+
+textwindows static int sys_sigtimedwait_nt_impl(sigset_t syncsigs,
+                                                siginfo_t *opt_info,
+                                                struct timespec deadline,
+                                                sigset_t waitmask,
+                                                intptr_t semaphore) {
+  for (;;) {
+    int sig;
+    if ((sig = sys_sigtimedwait_nt_check(syncsigs, opt_info, waitmask)))
+      return sig;
+    struct timespec now = sys_clock_gettime_monotonic_nt();
+    if (timespec_cmp(now, deadline) >= 0)
+      return eagain();
+    struct timespec remain = timespec_sub(deadline, now);
+    int64_t millis = timespec_tomillis(remain);
+    uint32_t waitms = MIN(millis, 0xffffffffu);
+    uint32_t wi = WaitForSingleObject(semaphore, waitms);
+    if (wi == -1u)
+      return __winerr();
+    if (wi)
+      return eagain();
+  }
+}
+
+textwindows int sys_sigtimedwait_nt(const sigset_t *set, siginfo_t *opt_info,
+                                    const struct timespec *opt_timeout) {
+  int rc;
+  intptr_t sem;
+  struct PosixThread *pt;
+  struct timespec deadline;
+  sigset_t syncsigs, waitmask;
+  BLOCK_SIGNALS;
+  if (opt_timeout) {
+    deadline = timespec_add(sys_clock_gettime_monotonic_nt(), *opt_timeout);
+  } else {
+    deadline = timespec_max;
+  }
+  if ((sem = CreateSemaphore(0, 0, 1, 0))) {
+    syncsigs = *set & ~(1ull << (SIGTHR - 1));  // internal to pthreads
+    waitmask = ~syncsigs & _SigMask;
+    pt = _pthread_self();
+    pt->pt_blkmask = waitmask;
+    pt->pt_semaphore = sem = CreateSemaphore(0, 0, 1, 0);
+    atomic_store_explicit(&pt->pt_blocker, PT_BLOCKER_SEM,
+                          memory_order_release);
+    rc = sys_sigtimedwait_nt_impl(syncsigs, opt_info, deadline, waitmask, sem);
+    atomic_store_explicit(&pt->pt_blocker, 0, memory_order_release);
+    CloseHandle(sem);
+  } else {
+    rc = __winerr();
+  }
+  ALLOW_SIGNALS;
+  return rc;
+}