rt: Rework lio_listio implementation

Move the common code into rt/lio_listio-common.c and include
the file in both rt/lio_listio.c and rt/lio_listio64.c.  The common
code automatically defines both public symbols for __WORDSIZE == 64.

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

1 files changed, 270 insertions, 0 deletions

diff --git a/rt/lio_listio-common.c b/rt/lio_listio-common.c
new file mode 100644
index 0000000000..3e087aa063
--- /dev/null
+++ b/rt/lio_listio-common.c
@@ -0,0 +1,270 @@
+/* Enqueue and list of read or write requests.  Common code template.
+   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
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/* The following macros must be defined before including this file:
+
+   LIO_LISTIO         The public symbol (lio_listio or lio_listio64).
+   AIOCB              Struct tag used by LIO_LISTIO (aiocb or aiocb64).
+   LIO_LISTIO_OLD     The internal symbol for the compat implementation.
+   LIO_LISTIO_NEW     The internal symbol for the current implementation.
+   LIO_OPCODE_BASE    Opcode shift for 64-bit version with 32-bit word size.
+
+   For __WORDSIZE == 64, LIO_LISTIO must always be lio_listio, and
+   lio_listio64 is automatically defined as well.  */
+
+#include <bits/wordsize.h>
+#if __WORDSIZE == 64
+# define lio_listio64 XXX
+# include <aio.h>
+/* And undo the hack.  */
+# undef lio_listio64
+#else
+# include <aio.h>
+#endif
+
+#include <assert.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <aio_misc.h>
+
+#include <shlib-compat.h>
+
+
+/* We need this special structure to handle asynchronous I/O.  */
+struct async_waitlist
+  {
+    unsigned int counter;
+    struct sigevent sigev;
+    struct waitlist list[0];
+  };
+
+
+/* The code in glibc 2.1 to glibc 2.4 issued only one event when all
+   requests submitted with lio_listio finished.  The existing practice
+   is to issue events for the individual requests as well.  This is
+   what the new code does.  */
+#if SHLIB_COMPAT (librt, GLIBC_2_1, GLIBC_2_4)
+# define LIO_MODE(mode) ((mode) & 127)
+# define NO_INDIVIDUAL_EVENT_P(mode) ((mode) & 128)
+#else
+# define LIO_MODE(mode) mode
+# define NO_INDIVIDUAL_EVENT_P(mode) 0
+#endif
+
+
+static int
+lio_listio_internal (int mode, struct AIOCB *const list[], int nent,
+		     struct sigevent *sig)
+{
+  struct sigevent defsigev;
+  struct requestlist *requests[nent];
+  int cnt;
+  volatile unsigned int total = 0;
+  int result = 0;
+
+  if (sig == NULL)
+    {
+      defsigev.sigev_notify = SIGEV_NONE;
+      sig = &defsigev;
+    }
+
+  /* Request the mutex.  */
+  pthread_mutex_lock (&__aio_requests_mutex);
+
+  /* Now we can enqueue all requests.  Since we already acquired the
+     mutex the enqueue function need not do this.  */
+  for (cnt = 0; cnt < nent; ++cnt)
+    if (list[cnt] != NULL && list[cnt]->aio_lio_opcode != LIO_NOP)
+      {
+	if (NO_INDIVIDUAL_EVENT_P (mode))
+	  list[cnt]->aio_sigevent.sigev_notify = SIGEV_NONE;
+
+	requests[cnt] = __aio_enqueue_request ((aiocb_union *) list[cnt],
+					       (list[cnt]->aio_lio_opcode
+						| LIO_OPCODE_BASE));
+
+	if (requests[cnt] != NULL)
+	  /* Successfully enqueued.  */
+	  ++total;
+	else
+	  /* Signal that we've seen an error.  `errno' and the error code
+	     of the aiocb will tell more.  */
+	  result = -1;
+      }
+    else
+      requests[cnt] = NULL;
+
+  if (total == 0)
+    {
+      /* We don't have anything to do except signalling if we work
+	 asynchronously.  */
+
+      /* Release the mutex.  We do this before raising a signal since the
+	 signal handler might do a `siglongjmp' and then the mutex is
+	 locked forever.  */
+      pthread_mutex_unlock (&__aio_requests_mutex);
+
+      if (LIO_MODE (mode) == LIO_NOWAIT)
+	__aio_notify_only (sig);
+
+      return result;
+    }
+  else if (LIO_MODE (mode) == LIO_WAIT)
+    {
+#ifndef DONT_NEED_AIO_MISC_COND
+      pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
+      int oldstate;
+#endif
+      struct waitlist waitlist[nent];
+
+      total = 0;
+      for (cnt = 0; cnt < nent; ++cnt)
+	{
+	  assert (requests[cnt] == NULL || list[cnt] != NULL);
+
+	  if (requests[cnt] != NULL && list[cnt]->aio_lio_opcode != LIO_NOP)
+	    {
+#ifndef DONT_NEED_AIO_MISC_COND
+	      waitlist[cnt].cond = &cond;
+#endif
+	      waitlist[cnt].result = &result;
+	      waitlist[cnt].next = requests[cnt]->waiting;
+	      waitlist[cnt].counterp = &total;
+	      waitlist[cnt].sigevp = NULL;
+	      requests[cnt]->waiting = &waitlist[cnt];
+	      ++total;
+	    }
+	}
+
+#ifdef DONT_NEED_AIO_MISC_COND
+      AIO_MISC_WAIT (result, total, NULL, 0);
+#else
+      /* Since `pthread_cond_wait'/`pthread_cond_timedwait' are cancellation
+	 points we must be careful.  We added entries to the waiting lists
+	 which we must remove.  So defer cancellation for now.  */
+      pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &oldstate);
+
+      while (total > 0)
+	pthread_cond_wait (&cond, &__aio_requests_mutex);
+
+      /* Now it's time to restore the cancellation state.  */
+      pthread_setcancelstate (oldstate, NULL);
+
+      /* Release the conditional variable.  */
+      if (pthread_cond_destroy (&cond) != 0)
+	/* This must never happen.  */
+	abort ();
+#endif
+
+      /* If any of the I/O requests failed, return -1 and set errno.  */
+      if (result != 0)
+	{
+	  __set_errno (result == EINTR ? EINTR : EIO);
+	  result = -1;
+	}
+    }
+  else
+    {
+      struct async_waitlist *waitlist;
+
+      waitlist = (struct async_waitlist *)
+	malloc (sizeof (struct async_waitlist)
+		+ (nent * sizeof (struct waitlist)));
+
+      if (waitlist == NULL)
+	{
+	  __set_errno (EAGAIN);
+	  result = -1;
+	}
+      else
+	{
+	  total = 0;
+
+	  for (cnt = 0; cnt < nent; ++cnt)
+	    {
+	      assert (requests[cnt] == NULL || list[cnt] != NULL);
+
+	      if (requests[cnt] != NULL
+		  && list[cnt]->aio_lio_opcode != LIO_NOP)
+		{
+#ifndef DONT_NEED_AIO_MISC_COND
+		  waitlist->list[cnt].cond = NULL;
+#endif
+		  waitlist->list[cnt].result = NULL;
+		  waitlist->list[cnt].next = requests[cnt]->waiting;
+		  waitlist->list[cnt].counterp = &waitlist->counter;
+		  waitlist->list[cnt].sigevp = &waitlist->sigev;
+		  requests[cnt]->waiting = &waitlist->list[cnt];
+		  ++total;
+		}
+	    }
+
+	  waitlist->counter = total;
+	  waitlist->sigev = *sig;
+	}
+    }
+
+  /* Release the mutex.  */
+  pthread_mutex_unlock (&__aio_requests_mutex);
+
+  return result;
+}
+
+
+#if SHLIB_COMPAT (librt, GLIBC_2_1, GLIBC_2_4)
+int
+attribute_compat_text_section
+LIO_LISTIO_OLD (int mode, struct AIOCB *const list[], int nent,
+                struct sigevent *sig)
+{
+  /* Check arguments.  */
+  if (mode != LIO_WAIT && mode != LIO_NOWAIT)
+    {
+      __set_errno (EINVAL);
+      return -1;
+    }
+
+  return lio_listio_internal (mode | LIO_NO_INDIVIDUAL_EVENT, list, nent, sig);
+}
+compat_symbol (librt, LIO_LISTIO_OLD, LIO_LISTIO, GLIBC_2_1);
+# if __WORDSIZE == 64
+compat_symbol (librt, LIO_LISTIO_OLD, lio_listio64, GLIBC_2_1);
+# endif
+#endif /* SHLIB_COMPAT */
+
+
+int
+LIO_LISTIO_NEW (int mode, struct AIOCB *const list[], int nent,
+                struct sigevent *sig)
+{
+    /* Check arguments.  */
+  if (mode != LIO_WAIT && mode != LIO_NOWAIT)
+    {
+      __set_errno (EINVAL);
+      return -1;
+    }
+
+  return lio_listio_internal (mode, list, nent, sig);
+}
+versioned_symbol (librt, LIO_LISTIO_NEW, LIO_LISTIO, GLIBC_2_4);
+#if __WORDSIZE == 64
+versioned_symbol (librt, LIO_LISTIO_NEW, lio_listio64, GLIBC_2_4);
+#endif