Add io_select_timeout to the io interface

This change fixes a problem that can occur with non-blocking (and also
blocking for very short times) select/poll calls. The problem occurs because
the timeout is implemented at the client side. For a non-blocking call, this
means that (depending on the code path taken in the C library) the client
could get a timeout without a full RPC round-trip to the server. Moving the
implementation of the timeout to the servers guarantees a full round-trip,
and correct results for non-blocking calls.

The modifications in this change depend on the availability of the recently
added pthread_hurd_cond_timedwait_np function in libpthread.

* boot/boot.c (io_select_common): New static function.
(S_io_select): Use io_select_common.
(S_io_select_timeout): New function which makes use of io_select_common.
* console-client/kbd-repeat.c (repeater_select): Add a timeout parameter.
* console-client/pc-mouse.c (repeater_select): Likewise.
* console-client/trans.c (io_select_common): New static function.
(netfs_S_io_select): Use io_select_common.
(netfs_S_io_select_timeout): New function which makes use of io_select_common.
* console-client/trans.h (struct consnode): Add a timeout parameter.
* hurd/io.defs (io_select_timeout): New MIG routine.
* hurd/io_reply.defs (io_select_timeout_reply): New MIG simpleroutine.
* hurd/io_request.defs (io_select_timeout_request): Likewise.
* libdiskfs/io-select.c (diskfs_S_io_select_timeout): New function.
* libnetfs/io-select.c (netfs_S_io_select_timeout): Likewise.
* libpipe/pipe.c (pipe_pair_select): Add a timeout parameter.
* libpipe/pipe.h (pipe_select_readable): Likewise.
(pipe_select_writable): Likewise.
(pipe_pair_select): Likewise.
* libpipe/pq.h: Include <hurd/hurd_types.h>.
* libtrivfs/io-select.c (trivfs_S_io_select_timeout): New function.
* pfinet/glue-include/linux/sched.h: Include <errno.h>.
(interruptible_sleep_on): Function removed, replaced with ...
(interruptible_sleep_on_timeout): New function.
(schedule): Update to use interruptible_sleep_on_timeout.
(schedule_timeout): Likewise.
* pfinet/io-ops.c (io_select_common): New static function.
(S_io_select): Use io_select_common.
(S_io_select_timeout): New function which makes use of io_select_common.
* pfinet/tunnel.c (io_select_common): New static function.
(trivfs_S_io_select): Use io_select_common.
(trivfs_S_io_select_timeout): New function which makes use of io_select_common.
* pflocal/connq.c (connq_listen): Replace noblock with a timeout parameter.
* pflocal/connq.h: Include <hurd/hurd_types.h>.
(connq_listen): Update declaration to replace noblock with a timeout parameter.
* pflocal/io.c (io_select_common): New static function.
(S_io_select): Use io_select_common.
(S_io_select_timeout): New function which makes use of io_select_common.
* pflocal/socket.c (S_socket_accept): Update call to connq_listen to match new
declaration.
* storeio/io.c (trivfs_S_io_select_timeout): New function.
* term/ptyio.c (pty_io_select): Add a timeout parameter.
* term/term.h (pty_io_select): Likewise.
* term/users.c (io_select_common): New static function.
(trivfs_S_io_select): Use io_select_common.
(trivfs_S_io_select_timeout): New function which makes use of io_select_common.
* trans/fifo.c (io_select_common): New static function.
(trivfs_S_io_select): Use io_select_common.
(trivfs_S_io_select_timeout): New function which makes use of io_select_common.
* trans/firmlink.c (trivfs_S_io_select_timeout): New function.
* trans/new-fifo.c (io_select_common): New static function.
(trivfs_S_io_select): Use io_select_common.
(trivfs_S_io_select_timeout): New function which makes use of io_select_common.
* trans/null.c (trivfs_S_io_select_timeout): New function.
* trans/streamio.c (io_select_common): New static function.
(trivfs_S_io_select): Use io_select_common.
(trivfs_S_io_select_timeout): New function which makes use of io_select_common.

1 files changed, 35 insertions, 6 deletions

diff --git a/boot/boot.c b/boot/boot.c
index fbbced77..0dbe1c20 100644
--- a/boot/boot.c
+++ b/boot/boot.c
@@ -1588,12 +1588,13 @@ S_io_get_icky_async_id (mach_port_t object,
   return EOPNOTSUPP;
 }
 
-kern_return_t
-S_io_select (mach_port_t object,
-	     mach_port_t reply_port,
-	     mach_msg_type_name_t reply_type,
-	     int *type)
+static kern_return_t
+io_select_common (mach_port_t object,
+		  mach_port_t reply_port,
+		  mach_msg_type_name_t reply_type,
+		  struct timespec *tsp, int *type)
 {
+  struct timeval tv, *tvp;
   fd_set r, w, x;
   int n;
 
@@ -1607,11 +1608,20 @@ S_io_select (mach_port_t object,
   FD_SET (0, &w);
   FD_SET (0, &x);
 
+  if (tsp == NULL)
+    tvp = NULL;
+  else
+    {
+      tv.tv_sec = tsp->tv_sec;
+      tv.tv_usec = tsp->tv_nsec / 1000;
+      tvp = &tv;
+    }
+
   n = select (1,
 	      (*type & SELECT_READ) ? &r : 0,
 	      (*type & SELECT_WRITE) ? &w : 0,
 	      (*type & SELECT_URG) ? &x : 0,
-	      0);
+	      tvp);
   if (n < 0)
     return errno;
 
@@ -1626,6 +1636,25 @@ S_io_select (mach_port_t object,
 }
 
 kern_return_t
+S_io_select (mach_port_t object,
+	     mach_port_t reply_port,
+	     mach_msg_type_name_t reply_type,
+	     int *type)
+{
+  return io_select_common (object, reply_port, reply_type, NULL, type);
+}
+
+kern_return_t
+S_io_select_timeout (mach_port_t object,
+		     mach_port_t reply_port,
+		     mach_msg_type_name_t reply_type,
+		     struct timespec ts,
+		     int *type)
+{
+  return io_select_common (object, reply_port, reply_type, &ts, type);
+}
+
+kern_return_t
 S_io_stat (mach_port_t object,
 	   mach_port_t reply_port,
 	   mach_msg_type_name_t reply_type,