[RFC PATCH 3/7] gdbserver linux-low: Convert linux_event_pipe to the event-pipe class.

[John Baldwin]

gdbserver/ChangeLog:

	* linux-low.cc: Include gdbsupport/event-pipe.h.
	(linux_event_pipe): Convert to an instance of event_pipe.
	(target_is_async_p, async_file_flush, async_file_mark): Implement
	as methods of event_pipe.
	(linux_process_target::async): Update to use event_pipe methods.
---
 gdbserver/ChangeLog    |  8 ++++++++
 gdbserver/linux-low.cc | 39 +++++++++------------------------------
 2 files changed, 17 insertions(+), 30 deletions(-)

diff --git a/gdbserver/ChangeLog b/gdbserver/ChangeLog
index f8d7fd65fb..843402b26f 100644
--- a/gdbserver/ChangeLog
+++ b/gdbserver/ChangeLog
@@ -1,3 +1,11 @@
+2021-06-04  John Baldwin  <jhb@FreeBSD.org>
+
+	* linux-low.cc: Include gdbsupport/event-pipe.h.
+	(linux_event_pipe): Convert to an instance of event_pipe.
+	(target_is_async_p, async_file_flush, async_file_mark): Implement
+	as methods of event_pipe.
+	(linux_process_target::async): Update to use event_pipe methods.
+
 2021-05-27  Simon Marchi  <simon.marchi@polymtl.ca>
 
 	* Fix some indentation mistakes throughout.
diff --git a/gdbserver/linux-low.cc b/gdbserver/linux-low.cc
index 5c6191d941..aeb7b9287f 100644
--- a/gdbserver/linux-low.cc
+++ b/gdbserver/linux-low.cc
@@ -21,6 +21,7 @@
 #include "nat/linux-osdata.h"
 #include "gdbsupport/agent.h"
 #include "tdesc.h"
+#include "gdbsupport/event-loop.h"
 #include "gdbsupport/rsp-low.h"
 #include "gdbsupport/signals-state-save-restore.h"
 #include "nat/linux-nat.h"
@@ -310,10 +311,10 @@ lwp_in_step_range (struct lwp_info *lwp)
 
 /* The read/write ends of the pipe registered as waitable file in the
    event loop.  */
-static int linux_event_pipe[2] = { -1, -1 };
+static event_pipe linux_event_pipe;
 
 /* True if we're currently in async mode.  */
-#define target_is_async_p() (linux_event_pipe[0] != -1)
+#define target_is_async_p() (linux_event_pipe.active ())
 
 static void send_sigstop (struct lwp_info *lwp);
 
@@ -3675,28 +3676,14 @@ linux_process_target::wait_1 (ptid_t ptid, target_waitstatus *ourstatus,
 static void
 async_file_flush (void)
 {
-  int ret;
-  char buf;
-
-  do
-    ret = read (linux_event_pipe[0], &buf, 1);
-  while (ret >= 0 || (ret == -1 && errno == EINTR));
+  linux_event_pipe.flush ();
 }
 
 /* Put something in the pipe, so the event loop wakes up.  */
 static void
 async_file_mark (void)
 {
-  int ret;
-
-  async_file_flush ();
-
-  do
-    ret = write (linux_event_pipe[1], "+", 1);
-  while (ret == 0 || (ret == -1 && errno == EINTR));
-
-  /* Ignore EAGAIN.  If the pipe is full, the event loop will already
-     be awakened anyway.  */
+  linux_event_pipe.mark ();
 }
 
 ptid_t
@@ -6096,21 +6083,16 @@ linux_process_target::async (bool enable)
 
       if (enable)
 	{
-	  if (pipe (linux_event_pipe) == -1)
+	  if (!linux_event_pipe.open ())
 	    {
-	      linux_event_pipe[0] = -1;
-	      linux_event_pipe[1] = -1;
 	      gdb_sigmask (SIG_UNBLOCK, &mask, NULL);
 
 	      warning ("creating event pipe failed.");
 	      return previous;
 	    }
 
-	  fcntl (linux_event_pipe[0], F_SETFL, O_NONBLOCK);
-	  fcntl (linux_event_pipe[1], F_SETFL, O_NONBLOCK);
-
 	  /* Register the event loop handler.  */
-	  add_file_handler (linux_event_pipe[0],
+	  add_file_handler (linux_event_pipe.event_fd (),
 			    handle_target_event, NULL,
 			    "linux-low");
 
@@ -6119,12 +6101,9 @@ linux_process_target::async (bool enable)
 	}
       else
 	{
-	  delete_file_handler (linux_event_pipe[0]);
+	  delete_file_handler (linux_event_pipe.event_fd ());
 
-	  close (linux_event_pipe[0]);
-	  close (linux_event_pipe[1]);
-	  linux_event_pipe[0] = -1;
-	  linux_event_pipe[1] = -1;
+	  linux_event_pipe.close ();
 	}
 
       gdb_sigmask (SIG_UNBLOCK, &mask, NULL);
-- 
2.31.1