Implement sigpending for sysv and nt (#597)

libc/calls/sig.internal.h

@@ -32,6 +32,7 @@ int __sig_add(int, int) hidden;
 int __sig_mask(int, const sigset_t *, sigset_t *) hidden;
 int __sig_raise(int, int) hidden;
 void __sig_check_ignore(const int, const unsigned) hidden;
+void __sig_pending(sigset_t *) hidden;
 
 COSMOPOLITAN_C_END_
 #endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */

libc/calls/sig2.c

@@ -298,3 +298,25 @@ textwindows void __sig_check_ignore(const int sig, const unsigned rva) {
     __sig_unlock();
   }
 }
+
+/**
+ * Determines the pending signals on New Technology.
+ *
+ * @param pending is to hold the pending signals
+ * @threadsafe
+ */
+textwindows void __sig_pending(sigset_t *pending) {
+  struct Signal *cur;
+  sigemptyset(pending);
+  if (__sig.queue) {
+    __sig_lock();
+    for (cur = __sig.queue; cur; cur = cur->next) {
+      if (__sighandrvas[cur->sig] != (unsigned)(intptr_t)SIG_IGN) {
+        pending->__bits[(cur->sig - 1) >> 6] |= (1ull << ((cur->sig - 1) & 63));
+      } else {
+        STRACE("%G is ignored", cur->sig);
+      }
+    }
+    __sig_unlock();
+  }
+}

libc/calls/sigpending.c

@@ -0,0 +1,61 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 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/sig.internal.h"
+#include "libc/calls/strace.internal.h"
+#include "libc/calls/struct/sigset.h"
+#include "libc/calls/struct/sigset.internal.h"
+#include "libc/dce.h"
+#include "libc/intrin/asan.internal.h"
+#include "libc/intrin/describeflags.internal.h"
+#include "libc/sysv/errfuns.h"
+
+/**
+ * Determines the blocked pending signals
+ *
+ * @param pending is where the bitset of pending signals is returned,
+ *     may not be NULL.
+ * @return -1 w/ EFAULT
+ * @asyncsignalsafe
+ */
+int sigpending(sigset_t *pending) {
+  int rc;
+  if (IsAsan() && !__asan_is_valid(pending, sizeof(*pending))) {
+    rc = efault();
+  } else if (IsLinux() || IsNetbsd() || IsOpenbsd() || IsFreebsd() || IsXnu()) {
+    rc = sys_sigpending(pending, 8);
+    // 128 signals on NetBSD and FreeBSD, 64 on Linux, 32 on OpenBSD and XNU.
+    if (IsOpenbsd()) {
+      pending->__bits[0] = (unsigned)rc;
+      rc = 0;
+    } else if (IsXnu()) {
+      pending->__bits[0] &= 0xFFFFFFFF;
+    }
+    if (IsLinux() || IsOpenbsd() || IsXnu()) {
+      pending->__bits[1] = 0;
+    }
+  } else if (IsWindows()) {
+    sigemptyset(pending);
+    __sig_pending(pending);
+    rc = 0;
+  } else {
+    rc = enosys();
+  }
+  STRACE("sigpending([%s]) → %d% m", DescribeSigset(rc, pending), rc);
+  return rc;
+}

libc/calls/struct/sigset.h

@@ -14,6 +14,7 @@ int sigfillset(sigset_t *) paramsnonnull();
 int sigismember(const sigset_t *, int) paramsnonnull() nosideeffect;
 int sigprocmask(int, const sigset_t *, sigset_t *);
 int sigsuspend(const sigset_t *);
+int sigpending(sigset_t *) paramsnonnull() nosideeffect;
 int pthread_sigmask(int, const sigset_t *, sigset_t *);
 
 COSMOPOLITAN_C_END_

libc/calls/struct/sigset.internal.h

@@ -9,6 +9,7 @@ int __sys_sigprocmask(int, const struct sigset *, struct sigset *,
                       uint64_t) hidden;
 int sys_sigprocmask(int, const struct sigset *, struct sigset *) hidden;
 int sys_sigsuspend(const struct sigset *, uint64_t) hidden;
+int sys_sigpending(struct sigset *, size_t) hidden;
 
 const char *DescribeSigset(char[128], int, const sigset_t *);
 #define DescribeSigset(rc, ss) DescribeSigset(alloca(128), rc, ss)