rt: Move generic implementation from sysdeps/pthread to rt

The pthread-based implementation is the generic one.  Replacing
the stubs makes it clear that they do not have to be adjusted for
the libpthread move.

Result of:

    git mv -f sysdeps/pthread/aio_misc.h sysdeps/generic/
    git mv sysdeps/pthread/timer_routines.c sysdeps/htl/
    git mv -f sysdeps/pthread/{aio,lio,timer}_*.c rt/

Followed by manual adjustment of the #include paths in
sysdeps/unix/sysv/linux/wordsize-64, and a move of the version
definitions formerly in sysdeps/pthread/Versions.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

1 files changed, 139 insertions, 5 deletions

diff --git a/rt/aio_notify.c b/rt/aio_notify.c
index 9d51fd9c5e..a8d61503d8 100644
--- a/rt/aio_notify.c
+++ b/rt/aio_notify.c
@@ -1,6 +1,7 @@
-/* Notify initiator of AIO request.  Stub version.
-   Copyright (C) 2001-2021 Free Software Foundation, Inc.
+/* Notify initiator of AIO request.
+   Copyright (C) 1997-2021 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
 
    The GNU C Library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
@@ -16,8 +17,141 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-#include <aio.h>
+#include <errno.h>
+#include <pthread.h>
+#include <stdlib.h>
+#include <unistd.h>
 #include <aio_misc.h>
+#include <signal.h>
 
-/* This file contains only internal functions used by
-   the particular aio_* implementation code.  */
+#ifndef aio_start_notify_thread
+# define aio_start_notify_thread() do { } while (0)
+#endif
+
+struct notify_func
+  {
+    void (*func) (sigval_t);
+    sigval_t value;
+  };
+
+static void *
+notify_func_wrapper (void *arg)
+{
+  aio_start_notify_thread ();
+  struct notify_func *const n = arg;
+  void (*func) (sigval_t) = n->func;
+  sigval_t value = n->value;
+  free (n);
+  (*func) (value);
+  return NULL;
+}
+
+
+int
+__aio_notify_only (struct sigevent *sigev)
+{
+  int result = 0;
+
+  /* Send the signal to notify about finished processing of the request.  */
+  if (__glibc_unlikely (sigev->sigev_notify == SIGEV_THREAD))
+    {
+      /* We have to start a thread.  */
+      pthread_t tid;
+      pthread_attr_t attr, *pattr;
+
+      pattr = (pthread_attr_t *) sigev->sigev_notify_attributes;
+      if (pattr == NULL)
+	{
+	  pthread_attr_init (&attr);
+	  pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
+	  pattr = &attr;
+	}
+
+      /* SIGEV may be freed as soon as we return, so we cannot let the
+	 notification thread use that pointer.  Even though a sigval_t is
+	 only one word and the same size as a void *, we cannot just pass
+	 the value through pthread_create as the argument and have the new
+	 thread run the user's function directly, because on some machines
+	 the calling convention for a union like sigval_t is different from
+	 that for a pointer type like void *.  */
+      struct notify_func *nf = malloc (sizeof *nf);
+      if (nf == NULL)
+	result = -1;
+      else
+	{
+	  nf->func = sigev->sigev_notify_function;
+	  nf->value = sigev->sigev_value;
+	  if (pthread_create (&tid, pattr, notify_func_wrapper, nf) < 0)
+	    {
+	      free (nf);
+	      result = -1;
+	    }
+	}
+    }
+  else if (sigev->sigev_notify == SIGEV_SIGNAL)
+    {
+      /* We have to send a signal.  */
+#if _POSIX_REALTIME_SIGNALS > 0
+      /* Note that the standard gives us the option of using a plain
+	 non-queuing signal here when SA_SIGINFO is not set for the signal.  */
+      if (__aio_sigqueue (sigev->sigev_signo, sigev->sigev_value, getpid ())
+	  < 0)
+	result = -1;
+#else
+      /* There are no queued signals on this system at all.  */
+      result = raise (sigev->sigev_signo);
+#endif
+    }
+
+  return result;
+}
+
+
+void
+__aio_notify (struct requestlist *req)
+{
+  struct waitlist *waitlist;
+  struct aiocb *aiocbp = &req->aiocbp->aiocb;
+
+  if (__aio_notify_only (&aiocbp->aio_sigevent) != 0)
+    {
+      /* XXX What shall we do if already an error is set by
+	 read/write/fsync?  */
+      aiocbp->__error_code = errno;
+      aiocbp->__return_value = -1;
+    }
+
+  /* Now also notify possibly waiting threads.  */
+  waitlist = req->waiting;
+  while (waitlist != NULL)
+    {
+      struct waitlist *next = waitlist->next;
+
+      if (waitlist->sigevp == NULL)
+	{
+	  if (waitlist->result != NULL && aiocbp->__return_value == -1)
+	    *waitlist->result = -1;
+
+#ifdef DONT_NEED_AIO_MISC_COND
+	  AIO_MISC_NOTIFY (waitlist);
+#else
+	  /* Decrement the counter.  */
+	  --*waitlist->counterp;
+
+	  pthread_cond_signal (waitlist->cond);
+#endif
+	}
+      else
+	/* This is part of an asynchronous `lio_listio' operation.  If
+	   this request is the last one, send the signal.  */
+	if (--*waitlist->counterp == 0)
+	  {
+	    __aio_notify_only (waitlist->sigevp);
+	    /* This is tricky.  See lio_listio.c for the reason why
+	       this works.  */
+	    free ((void *) waitlist->counterp);
+	  }
+
+      waitlist = next;
+    }
+}