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.

5 files changed, 92 insertions, 16 deletions

diff --git a/trans/fifo.c b/trans/fifo.c
index b40a50d1..e6fbd0e9 100644
--- a/trans/fifo.c
+++ b/trans/fifo.c
@@ -405,10 +405,10 @@ trivfs_S_io_seek (struct trivfs_protid *cred,
    return the types that are then available.  ID_TAG is returned as passed; it
    is just for the convenience of the user in matching up reply messages with
    specific requests sent.  */
-error_t
-trivfs_S_io_select (struct trivfs_protid *cred,
-		    mach_port_t reply, mach_msg_type_name_t reply_type,
-		    int *select_type)
+static error_t
+io_select_common (struct trivfs_protid *cred,
+		  mach_port_t reply, mach_msg_type_name_t reply_type,
+		  struct timespec *tsp, int *select_type)
 {
   struct pipe *pipe;
   error_t err = 0;
@@ -466,11 +466,28 @@ trivfs_S_io_select (struct trivfs_protid *cred,
     /* Wait for something to change.  */
     {
       ports_interrupt_self_on_port_death (cred, reply);
-      err = pipe_pair_select (pipe, pipe, select_type, 1);
+      err = pipe_pair_select (pipe, pipe, tsp, select_type, 1);
     }
 
   return err;
 }
+
+error_t
+trivfs_S_io_select (struct trivfs_protid *cred,
+		    mach_port_t reply, mach_msg_type_name_t reply_type,
+		    int *select_type)
+{
+  return io_select_common (cred, reply, reply_type, NULL, select_type);
+}
+
+error_t
+trivfs_S_io_select_timeout (struct trivfs_protid *cred,
+			    mach_port_t reply, mach_msg_type_name_t reply_type,
+			    struct timespec ts,
+			    int *select_type)
+{
+  return io_select_common (cred, reply, reply_type, &ts, select_type);
+}
 
 /* ---------------------------------------------------------------- */
 
diff --git a/trans/firmlink.c b/trans/firmlink.c
index 087e19d0..9c063c04 100644
--- a/trans/firmlink.c
+++ b/trans/firmlink.c
@@ -275,3 +275,12 @@ trivfs_S_io_select (struct trivfs_protid *cred,
 {
   return EOPNOTSUPP;
 }
+
+error_t
+trivfs_S_io_select_timeout (struct trivfs_protid *cred,
+			    mach_port_t reply, mach_msg_type_name_t reply_type,
+			    struct timespec ts,
+			    int *type)
+{
+  return trivfs_S_io_select (cred, reply, reply_type, type);
+}
diff --git a/trans/new-fifo.c b/trans/new-fifo.c
index 5cc44b58..dc3cc79e 100644
--- a/trans/new-fifo.c
+++ b/trans/new-fifo.c
@@ -591,10 +591,10 @@ trivfs_S_io_seek (struct trivfs_protid *cred,
    return the types that are then available.  ID_TAG is returned as passed; it
    is just for the convenience of the user in matching up reply messages with
    specific requests sent.  */
-error_t
-trivfs_S_io_select (struct trivfs_protid *cred,
-		    mach_port_t reply, mach_msg_type_name_t reply_type,
-		    int *select_type)
+static error_t
+io_select_common (struct trivfs_protid *cred,
+		  mach_port_t reply, mach_msg_type_name_t reply_type,
+		  struct timespec *tsp, int *select_type)
 {
   struct pipe *pipe;
   error_t err = 0;
@@ -652,11 +652,28 @@ trivfs_S_io_select (struct trivfs_protid *cred,
     /* Wait for something to change.  */
     {
       ports_interrupt_self_on_port_death (cred, reply);
-      err = pipe_pair_select (pipe, pipe, select_type, 1);
+      err = pipe_pair_select (pipe, pipe, tsp, select_type, 1);
     }
 
   return err;
 }
+
+error_t
+trivfs_S_io_select (struct trivfs_protid *cred,
+		    mach_port_t reply, mach_msg_type_name_t reply_type,
+		    int *select_type)
+{
+  return io_select_common (cred, reply, reply_type, NULL, select_type);
+}
+
+error_t
+trivfs_S_io_select_timeout (struct trivfs_protid *cred,
+			    mach_port_t reply, mach_msg_type_name_t reply_type,
+			    struct timespec ts,
+			    int *select_type)
+{
+  return io_select_common (cred, reply, reply_type, &ts, select_type);
+}
 
 /* ---------------------------------------------------------------- */
 
diff --git a/trans/null.c b/trans/null.c
index 9673a758..1f985b39 100644
--- a/trans/null.c
+++ b/trans/null.c
@@ -203,6 +203,15 @@ trivfs_S_io_select (struct trivfs_protid *cred,
     *type &= ~SELECT_URG;
   return 0;
 }
+
+kern_return_t
+trivfs_S_io_select_timeout (struct trivfs_protid *cred,
+			    mach_port_t reply, mach_msg_type_name_t replytype,
+			    struct timespec ts,
+			    int *type)
+{
+  return trivfs_S_io_select (cred, reply, replytype, type);
+}
 
 /* Write data to an IO object.  If offset is -1, write at the object
    maintained file pointer.  If the object is not seekable, offset is
diff --git a/trans/streamio.c b/trans/streamio.c
index 60b5d59c..8ff3dc63 100644
--- a/trans/streamio.c
+++ b/trans/streamio.c
@@ -538,12 +538,14 @@ trivfs_S_io_seek (struct trivfs_protid *cred,
     return ESPIPE;
 }
 
-error_t
-trivfs_S_io_select (struct trivfs_protid *cred,
-		    mach_port_t reply, mach_msg_type_name_t reply_type,
-		    int *type)
+static error_t
+io_select_common (struct trivfs_protid *cred,
+		  mach_port_t reply, mach_msg_type_name_t reply_type,
+		  struct timespec *tsp,
+		  int *type)
 {
   int available;
+  error_t err;
 
   if (!cred)
     return EOPNOTSUPP;
@@ -583,16 +585,38 @@ trivfs_S_io_select (struct trivfs_protid *cred,
 	}
 
       ports_interrupt_self_on_port_death (cred, reply);
-      if (pthread_hurd_cond_wait_np (&select_alert, &global_lock))
+      err = pthread_hurd_cond_timedwait_np (&select_alert, &global_lock, tsp);
+      if (err)
 	{
 	  *type = 0;
 	  pthread_mutex_unlock (&global_lock);
-	  return EINTR;
+
+	  if (err == ETIMEDOUT)
+	    err = 0;
+
+	  return err;
 	}
     }
 }
 
 error_t
+trivfs_S_io_select (struct trivfs_protid *cred,
+		    mach_port_t reply, mach_msg_type_name_t reply_type,
+		    int *type)
+{
+  return io_select_common (cred, reply, reply_type, NULL, type);
+}
+
+error_t
+trivfs_S_io_select_timeout (struct trivfs_protid *cred,
+			    mach_port_t reply, mach_msg_type_name_t reply_type,
+			    struct timespec ts,
+			    int *type)
+{
+  return io_select_common (cred, reply, reply_type, &ts, type);
+}
+
+error_t
 trivfs_S_file_set_size (struct trivfs_protid *cred,
 			mach_port_t reply, mach_msg_type_name_t reply_type,
 			off_t size)