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.

29 files changed, 441 insertions, 102 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,
diff --git a/console-client/kbd-repeat.c b/console-client/kbd-repeat.c
index 641520ca..d3a39d07 100644
--- a/console-client/kbd-repeat.c
+++ b/console-client/kbd-repeat.c
@@ -86,8 +86,11 @@ kbd_repeat_key (kd_event *key)
 
 static error_t
 repeater_select (struct protid *cred, mach_port_t reply,
-		 mach_msg_type_name_t replytype, int *type)
+		 mach_msg_type_name_t replytype,
+		 struct timespec *tsp, int *type)
 {
+  error_t err;
+
   if (!cred)
     return EOPNOTSUPP;
 
@@ -109,12 +112,16 @@ repeater_select (struct protid *cred, mach_port_t reply,
 	}
       
       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;
 	}
     }
 }
diff --git a/console-client/pc-mouse.c b/console-client/pc-mouse.c
index 2cec2042..8be7ff1c 100644
--- a/console-client/pc-mouse.c
+++ b/console-client/pc-mouse.c
@@ -110,8 +110,11 @@ repeat_event (kd_event *evt)
 
 static error_t
 repeater_select (struct protid *cred, mach_port_t reply,
-		 mach_msg_type_name_t replytype, int *type)
+		 mach_msg_type_name_t replytype,
+		 struct timespec *tsp, int *type)
 {
+  error_t err;
+
   if (!cred)
     return EOPNOTSUPP;
 
@@ -133,12 +136,16 @@ repeater_select (struct protid *cred, mach_port_t reply,
 	}
 
       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;
 	}
     }
 }
diff --git a/console-client/trans.c b/console-client/trans.c
index 67c84b4e..6949af5e 100644
--- a/console-client/trans.c
+++ b/console-client/trans.c
@@ -332,9 +332,10 @@ netfs_S_io_seek (struct protid *user, off_t offset,
 }
 
 
-error_t
-netfs_S_io_select (struct protid *user, mach_port_t reply,
-		   mach_msg_type_name_t replytype, int *type)
+static error_t
+io_select_common (struct protid *user, mach_port_t reply,
+		  mach_msg_type_name_t replytype,
+		  struct timespec *tsp, int *type)
 {
   struct node *np;
   
@@ -344,11 +345,28 @@ netfs_S_io_select (struct protid *user, mach_port_t reply,
   np = user->po->np;
   
   if (np->nn->node && np->nn->node->select)
-    return np->nn->node->select (user, reply, replytype, type);
+    return np->nn->node->select (user, reply, replytype, tsp, type);
   return EOPNOTSUPP;
 }
 
 
+error_t
+netfs_S_io_select (struct protid *user, mach_port_t reply,
+		   mach_msg_type_name_t replytype, int *type)
+{
+  return io_select_common (user, reply, replytype, NULL, type);
+}
+
+
+error_t
+netfs_S_io_select_timeout (struct protid *user, mach_port_t reply,
+			   mach_msg_type_name_t replytype,
+			   struct timespec ts, int *type)
+{
+  return io_select_common (user, reply, replytype, &ts, type);
+}
+
+
 /* Delete NAME in DIR (which is locked) for USER.  */
 error_t
 netfs_attempt_unlink (struct iouser *user, struct node *dir,
diff --git a/console-client/trans.h b/console-client/trans.h
index f781e31f..9891cf3f 100644
--- a/console-client/trans.h
+++ b/console-client/trans.h
@@ -41,9 +41,10 @@ struct consnode
 		    mach_msg_type_number_t datalen, off_t offset,
 		    mach_msg_type_number_t *amount);
 
-  /* This is exactly the same as io_select does.  */
+  /* This is exactly the same as io_select{,_timeout} do.  */
   error_t (*select) (struct protid *user, mach_port_t reply,
-		     mach_msg_type_name_t replytype, int *type);
+		     mach_msg_type_name_t replytype,
+		     struct timespec *tsp, int *type);
 
   /* Called when the node is opened.  */
   void (*open) (void);
diff --git a/hurd/io.defs b/hurd/io.defs
index 9119b05b..ba0b8077 100644
--- a/hurd/io.defs
+++ b/hurd/io.defs
@@ -320,3 +320,14 @@ routine io_identity (
    on the specified object.  */
 routine io_revoke (
 	io_object: io_t RPTLAST);
+
+/* INTR */
+routine io_select_timeout (
+	io_object: io_t;
+#if defined (REPLY_PORTS) || defined (IO_SELECT_REPLY_PORT)
+	replyport reply: sreply_port_t;
+#else
+	ureplyport reply: mach_port_make_send_t;
+#endif
+	timeout: timespec_t;
+	inout select_type: int);
diff --git a/hurd/io_reply.defs b/hurd/io_reply.defs
index ffc4e752..eee68244 100644
--- a/hurd/io_reply.defs
+++ b/hurd/io_reply.defs
@@ -175,3 +175,8 @@ simpleroutine io_identity_reply (
 simpleroutine io_revoke_reply (
 	reply: reply_port_t;
 	RETURN_CODE_ARG);
+
+simpleroutine io_select_timeout_reply (
+	reply: reply_port_t;
+	RETURN_CODE_ARG;
+	select_result: int);
diff --git a/hurd/io_request.defs b/hurd/io_request.defs
index a3e775aa..0d5e36dd 100644
--- a/hurd/io_request.defs
+++ b/hurd/io_request.defs
@@ -172,3 +172,9 @@ simpleroutine io_identity_request (
 simpleroutine io_revoke_request (
 		io_object: io_t;
 		reply: reply_port_t);
+
+simpleroutine io_select_timeout_request (
+		io_object: io_t;
+		ureplyport reply: mach_port_make_send_t;
+		timeout: timespec_t;
+		select_type: int);
diff --git a/libdiskfs/io-select.c b/libdiskfs/io-select.c
index 07112f7b..ddac738f 100644
--- a/libdiskfs/io-select.c
+++ b/libdiskfs/io-select.c
@@ -30,3 +30,11 @@ diskfs_S_io_select (struct protid *cred,
   *type &= ~SELECT_URG;
   return 0;
 }
+
+kern_return_t
+diskfs_S_io_select_timeout (struct protid *cred,
+			    struct timespec ts,
+			    int *type)
+{
+  return diskfs_S_io_select (cred, type);
+}
diff --git a/libnetfs/io-select.c b/libnetfs/io-select.c
index c72eba6b..63036145 100644
--- a/libnetfs/io-select.c
+++ b/libnetfs/io-select.c
@@ -34,3 +34,13 @@ netfs_S_io_select (struct protid *user,
   *type &= ~SELECT_URG;
   return 0;
 }
+
+error_t
+netfs_S_io_select_timeout (struct protid *user,
+			   mach_port_t reply,
+			   mach_msg_type_name_t replytype,
+			   struct timespec ts,
+			   int *type)
+{
+  return netfs_S_io_select (user, reply, replytype, type);
+}
diff --git a/libpipe/pipe.c b/libpipe/pipe.c
index dd306f60..1ddaf126 100644
--- a/libpipe/pipe.c
+++ b/libpipe/pipe.c
@@ -209,7 +209,7 @@ void _pipe_no_writers (struct pipe *pipe)
    this function (unlike most pipe functions).  */
 error_t
 pipe_pair_select (struct pipe *rpipe, struct pipe *wpipe,
-		  int *select_type, int data_only)
+		  struct timespec *tsp, int *select_type, int data_only)
 {
   error_t err = 0;
 
@@ -218,13 +218,13 @@ pipe_pair_select (struct pipe *rpipe, struct pipe *wpipe,
   if (*select_type == SELECT_READ)
     {
       pthread_mutex_lock (&rpipe->lock);
-      err = pipe_select_readable (rpipe, data_only);
+      err = pipe_select_readable (rpipe, tsp, data_only);
       pthread_mutex_unlock (&rpipe->lock);
     }
   else if (*select_type == SELECT_WRITE)
     {
       pthread_mutex_lock (&wpipe->lock);
-      err = pipe_select_writable (wpipe);
+      err = pipe_select_writable (wpipe, tsp);
       pthread_mutex_unlock (&wpipe->lock);
     }
   else
@@ -260,8 +260,8 @@ pipe_pair_select (struct pipe *rpipe, struct pipe *wpipe,
 	      pthread_mutex_unlock (&rpipe->lock);
 	      pthread_mutex_unlock (&wpipe->lock);
 	    }
-	  if (pthread_hurd_cond_wait_np (&pending_select.cond, lock))
-	    err = EINTR;
+	  err = pthread_hurd_cond_timedwait_np (&pending_select.cond, lock,
+						tsp);
 	  if (rpipe != wpipe)
 	    {
 	      pthread_mutex_lock (&rpipe->lock);
@@ -295,6 +295,12 @@ pipe_pair_select (struct pipe *rpipe, struct pipe *wpipe,
       pthread_mutex_unlock (lock);
     }
 
+  if (err == ETIMEDOUT)
+    {
+      err = 0;
+      *select_type = 0;
+    }
+
   return err;
 }
 
diff --git a/libpipe/pipe.h b/libpipe/pipe.h
index b8e70681..040204d5 100644
--- a/libpipe/pipe.h
+++ b/libpipe/pipe.h
@@ -126,11 +126,12 @@ extern int pipe_is_readable (struct pipe *pipe, int data_only);
 
 extern error_t pipe_wait_readable (struct pipe *pipe, int noblock, int data_only);
 
-extern error_t pipe_select_readable (struct pipe *pipe, int data_only);
+extern error_t pipe_select_readable (struct pipe *pipe, struct timespec *tsp,
+				     int data_only);
 
 extern error_t pipe_wait_writable (struct pipe *pipe, int noblock);
 
-extern error_t pipe_select_writable (struct pipe *pipe);
+extern error_t pipe_select_writable (struct pipe *pipe, struct timespec *tsp);
 
 #if defined(__USE_EXTERN_INLINES) || defined(PIPE_DEFINE_EI)
 
@@ -188,12 +189,17 @@ pipe_wait_readable (struct pipe *pipe, int noblock, int data_only)
    given a chance to read, and if there is still data available thereafter.
    If DATA_ONLY is true, then `control' packets are ignored.  */
 PIPE_EI error_t
-pipe_select_readable (struct pipe *pipe, int data_only)
+pipe_select_readable (struct pipe *pipe, struct timespec *tsp, int data_only)
 {
+  error_t err = 0;
   while (! pipe_is_readable (pipe, data_only) && ! (pipe->flags & PIPE_BROKEN))
-    if (pthread_hurd_cond_wait_np (&pipe->pending_read_selects, &pipe->lock))
-      return EINTR;
-  return 0;
+    {
+      err = pthread_hurd_cond_timedwait_np (&pipe->pending_read_selects,
+					    &pipe->lock, tsp);
+      if (err)
+	break;
+    }
+  return err;
 }
 
 /* Block until data can be written to PIPE.  If NOBLOCK is true, then
@@ -221,13 +227,18 @@ pipe_wait_writable (struct pipe *pipe, int noblock)
    threads waiting using pipe_wait_writable have been woken and given a
    chance to write, and if there is still space available thereafter.  */
 PIPE_EI error_t
-pipe_select_writable (struct pipe *pipe)
+pipe_select_writable (struct pipe *pipe, struct timespec *tsp)
 {
   size_t limit = pipe->write_limit;
+  error_t err = 0;
   while (! (pipe->flags & PIPE_BROKEN) && pipe_readable (pipe, 1) >= limit)
-    if (pthread_hurd_cond_wait_np (&pipe->pending_writes, &pipe->lock))
-      return EINTR;
-  return 0;
+    {
+      err = pthread_hurd_cond_timedwait_np (&pipe->pending_writes,
+					    &pipe->lock, tsp);
+      if (err)
+	break;
+    }
+  return err;
 }
 
 #endif /* Use extern inlines.  */
@@ -419,7 +430,8 @@ extern pthread_mutex_t pipe_multiple_lock;
    waited for on RPIPE.  Neither RPIPE or WPIPE should be locked when calling
    this function (unlike most pipe functions).  */
 error_t pipe_pair_select (struct pipe *rpipe, struct pipe *wpipe,
-			  int *select_type, int data_only);
+			  struct timespec *tsp, int *select_type,
+			  int data_only);
 
 /* ---------------------------------------------------------------- */
 /* User-provided functions.  */
diff --git a/libtrivfs/io-select.c b/libtrivfs/io-select.c
index 9df24d61..e44a8365 100644
--- a/libtrivfs/io-select.c
+++ b/libtrivfs/io-select.c
@@ -36,3 +36,13 @@ trivfs_S_io_select (struct trivfs_protid *cred,
     assert (!trivfs_support_write);
   return EOPNOTSUPP;
 }
+
+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 *seltype)
+{
+  return trivfs_S_io_select (cred, reply, replytype, seltype);
+}
diff --git a/pfinet/glue-include/linux/sched.h b/pfinet/glue-include/linux/sched.h
index aea6c47a..26ab10a8 100644
--- a/pfinet/glue-include/linux/sched.h
+++ b/pfinet/glue-include/linux/sched.h
@@ -8,6 +8,7 @@
 #include <limits.h>
 #include <assert.h>
 #include <pthread.h>
+#include <errno.h>
 
 #include "mapped-time.h"
 
@@ -92,12 +93,13 @@ capable(int cap)
 
 extern pthread_mutex_t global_lock;
 
-static inline void
-interruptible_sleep_on (struct wait_queue **p)
+static inline int
+interruptible_sleep_on_timeout (struct wait_queue **p, struct timespec *tsp)
 {
   pthread_cond_t **condp = (void *) p, *c;
   int isroot;
   struct wait_queue **next_wait;
+  error_t err;
 
   c = *condp;
   if (c == 0)
@@ -111,12 +113,13 @@ interruptible_sleep_on (struct wait_queue **p)
   isroot = current->isroot;	/* This is our context that needs switched.  */
   next_wait = current->next_wait; /* This too, for multiple schedule calls.  */
   current->next_wait = 0;
-  if (pthread_hurd_cond_wait_np (c, &global_lock))
+  err = pthread_hurd_cond_timedwait_np(c, &global_lock, tsp);
+  if (err == EINTR)
     current->signal = 1;	/* We got cancelled, mark it for later.  */
   current->isroot = isroot;	/* Switch back to our context.  */
   current->next_wait = next_wait;
+  return (err == ETIMEDOUT);
 }
-#define sleep_on	interruptible_sleep_on
 
 static inline void
 wake_up_interruptible (struct wait_queue **p)
@@ -146,7 +149,7 @@ static inline void
 schedule (void)
 {
   assert (current->next_wait);
-  interruptible_sleep_on (current->next_wait);
+  interruptible_sleep_on_timeout (current->next_wait, NULL);
 }
 
 static inline void
@@ -171,7 +174,7 @@ schedule_timeout (long timeout)
   timer.function = process_schedule_timeout;
   add_timer (&timer);
 
-  interruptible_sleep_on (&sleep);
+  interruptible_sleep_on_timeout (&sleep, NULL);
   if (signal_pending (current))
     {
       /* We were canceled.  */
diff --git a/pfinet/io-ops.c b/pfinet/io-ops.c
index 5f3b1e90..69bd93c5 100644
--- a/pfinet/io-ops.c
+++ b/pfinet/io-ops.c
@@ -251,14 +251,14 @@ S_io_clear_some_openmodes (struct sock_user *user,
   return 0;
 }
 
-error_t
-S_io_select (struct sock_user *user,
-	     mach_port_t reply,
-	     mach_msg_type_name_t reply_type,
-	     int *select_type)
+static error_t
+io_select_common (struct sock_user *user,
+		  mach_port_t reply,
+		  mach_msg_type_name_t reply_type,
+		  struct timespec *tsp, int *select_type)
 {
   const int want = *select_type | POLLERR;
-  int avail;
+  int avail, timedout;
   int ret = 0;
 
   if (!user)
@@ -281,9 +281,16 @@ S_io_select (struct sock_user *user,
 
       do
 	{
-	  /* Block until we are woken or cancelled.  */
-	  interruptible_sleep_on (user->sock->sk->sleep);
-	  if (signal_pending (current)) /* This means we were cancelled.  */
+	  /* Block until we time out, are woken or cancelled.  */
+	  timedout = interruptible_sleep_on_timeout (user->sock->sk->sleep,
+						     tsp);
+	  if (timedout)
+	    {
+	      __mutex_unlock (&global_lock);
+	      *select_type = 0;
+	      return 0;
+	    }
+	  else if (signal_pending (current)) /* This means we were cancelled.  */
 	    {
 	      pthread_mutex_unlock (&global_lock);
 	      return EINTR;
@@ -307,6 +314,25 @@ S_io_select (struct sock_user *user,
 }
 
 error_t
+S_io_select (struct sock_user *user,
+	     mach_port_t reply,
+	     mach_msg_type_name_t reply_type,
+	     int *select_type)
+{
+  return io_select_common (user, reply, reply_type, NULL, select_type);
+}
+
+error_t
+S_io_select_timeout (struct sock_user *user,
+		     mach_port_t reply,
+		     mach_msg_type_name_t reply_type,
+		     struct timespec ts,
+		     int *select_type)
+{
+  return io_select_common (user, reply, reply_type, &ts, select_type);
+}
+
+error_t
 S_io_stat (struct sock_user *user,
 	   struct stat *st)
 {
diff --git a/pfinet/tunnel.c b/pfinet/tunnel.c
index 5d2544b2..4a6f616a 100644
--- a/pfinet/tunnel.c
+++ b/pfinet/tunnel.c
@@ -462,13 +462,14 @@ trivfs_S_io_readable (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 *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)
 {
   struct tunnel_device *tdev;
+  error_t err;
 
   if (!cred)
     return EOPNOTSUPP;
@@ -497,15 +498,40 @@ trivfs_S_io_select (struct trivfs_protid *cred,
 
       ports_interrupt_self_on_port_death (cred, reply);
       tdev->read_blocked = 1;
-      if (pthread_hurd_cond_wait_np (&tdev->select_alert, &tdev->lock))
+      err = pthread_hurd_cond_timedwait_np (&tdev->select_alert, &tdev->lock,
+					    tsp);
+      if (err)
         {
           *type = 0;
           pthread_mutex_unlock (&tdev->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);
+}
+
 /* Change current read/write offset */
 error_t
 trivfs_S_io_seek (struct trivfs_protid *cred,
diff --git a/pflocal/connq.c b/pflocal/connq.c
index ab2b3a55..d88711e3 100644
--- a/pflocal/connq.c
+++ b/pflocal/connq.c
@@ -141,16 +141,19 @@ connq_destroy (struct connq *cq)
 /* ---------------------------------------------------------------- */
 
 /* Return a connection request on CQ.  If SOCK is NULL, the request is
-   left in the queue.  If NOBLOCK is true, EWOULDBLOCK is returned
-   when there are no immediate connections available.  */
+   left in the queue.  If TIMEOUT denotes a value of 0, EWOULDBLOCK is
+   returned when there are no immediate connections available.
+   Otherwise this value is used to limit the wait duration.  If TIMEOUT
+   is NULL, the wait duration isn't bounded.  */
 error_t
-connq_listen (struct connq *cq, int noblock, struct sock **sock)
+connq_listen (struct connq *cq, struct timespec *tsp, struct sock **sock)
 {
   error_t err = 0;
 
   pthread_mutex_lock (&cq->lock);
 
-  if (noblock && cq->count == 0 && cq->num_connectors == 0)
+  if (tsp && tsp->tv_sec == 0 && tsp->tv_nsec == 0 && cq->count == 0
+      && cq->num_connectors == 0)
     {
       pthread_mutex_unlock (&cq->lock);
       return EWOULDBLOCK;
@@ -176,12 +179,14 @@ connq_listen (struct connq *cq, int noblock, struct sock **sock)
 	pthread_cond_signal (&cq->connectors);
 
       do
-	if (pthread_hurd_cond_wait_np (&cq->listeners, &cq->lock))
+	{
+	  err = pthread_hurd_cond_timedwait_np (&cq->listeners, &cq->lock, tsp);
+	  if (err)
 	  {
 	    cq->num_listeners--;
-	    err = EINTR;
 	    goto out;
 	  }
+	}
       while (cq->count == 0);
     }
 
diff --git a/pflocal/connq.h b/pflocal/connq.h
index 9278d007..71583800 100644
--- a/pflocal/connq.h
+++ b/pflocal/connq.h
@@ -36,9 +36,12 @@ error_t connq_create (struct connq **cq);
 void connq_destroy (struct connq *cq);
 
 /* Return a connection request on CQ.  If SOCK is NULL, the request is
-   left in the queue.  If NOBLOCK is true, EWOULDBLOCK is returned
-   when there are no immediate connections available.  */
-error_t connq_listen (struct connq *cq, int noblock, struct sock **sock);
+   left in the queue.  If TIMEOUT denotes a value of 0, EWOULDBLOCK is
+   returned when there are no immediate connections available.
+   Otherwise this value is used to limit the wait duration.  If TIMEOUT
+   is NULL, the wait duration isn't bounded.  */
+error_t connq_listen (struct connq *cq, struct timespec *tsp,
+		      struct sock **sock);
 
 /* Try to connect SOCK with the socket listening on CQ.  If NOBLOCK is
    true, then return EWOULDBLOCK if there are no connections
diff --git a/pflocal/io.c b/pflocal/io.c
index 2301611e..0dec56e0 100644
--- a/pflocal/io.c
+++ b/pflocal/io.c
@@ -172,10 +172,10 @@ S_io_duplicate (struct sock_user *user,
 /* SELECT_TYPE is the bitwise OR of SELECT_READ, SELECT_WRITE, and SELECT_URG.
    Block until one of the indicated types of i/o can be done "quickly", and
    return the types that are then available.  */
-error_t
-S_io_select (struct sock_user *user,
-	     mach_port_t reply, mach_msg_type_name_t reply_type,
-	     int *select_type)
+static error_t
+io_select_common (struct sock_user *user,
+		  mach_port_t reply, mach_msg_type_name_t reply_type,
+		  struct timespec *tsp, int *select_type)
 {
   error_t err = 0;
   struct sock *sock;
@@ -199,16 +199,24 @@ S_io_select (struct sock_user *user,
 
       if (*select_type & SELECT_READ)
 	{
+	  struct timespec noblock = {0, 0};
+
 	  /* Wait for a connect.  Passing in NULL for SOCK means that
 	     the request won't be dequeued.  */
-	  if (connq_listen (sock->listen_queue, 1, NULL) == 0)
+	  if (connq_listen (sock->listen_queue, &noblock, NULL) == 0)
 	    /* We can satisfy this request immediately. */
 	    return 0;
 	  else
 	    /* Gotta wait...  */
 	    {
 	      ports_interrupt_self_on_port_death (user, reply);
-	      return connq_listen (sock->listen_queue, 0, NULL);
+	      err = connq_listen (sock->listen_queue, tsp, NULL);
+	      if (err == ETIMEDOUT)
+		{
+		  *select_type = 0;
+		  err = 0;
+		}
+	      return err;
 	    }
 	}
     }
@@ -261,7 +269,7 @@ S_io_select (struct sock_user *user,
 	/* Wait for something to change.  */
 	{
 	  ports_interrupt_self_on_port_death (user, reply);
-	  err = pipe_pair_select (read_pipe, write_pipe, select_type, 1);
+	  err = pipe_pair_select (read_pipe, write_pipe, tsp, select_type, 1);
 	}
 
       if (valid & SELECT_READ)
@@ -272,6 +280,23 @@ S_io_select (struct sock_user *user,
 
   return err;
 }
+
+error_t
+S_io_select (struct sock_user *user,
+	     mach_port_t reply, mach_msg_type_name_t reply_type,
+	     int *select_type)
+{
+  return io_select_common (user, reply, reply_type, NULL, select_type);
+}
+
+error_t
+S_io_select_timeout (struct sock_user *user,
+		     mach_port_t reply, mach_msg_type_name_t reply_type,
+		     struct timespec ts,
+		     int *select_type)
+{
+  return io_select_common (user, reply, reply_type, &ts, select_type);
+}
 
 /* Return the current status of the object.  Not all the fields of the
    io_statuf_t are meaningful for all objects; however, the access and
diff --git a/pflocal/socket.c b/pflocal/socket.c
index 65da7487..ce1edd82 100644
--- a/pflocal/socket.c
+++ b/pflocal/socket.c
@@ -178,9 +178,11 @@ S_socket_accept (struct sock_user *user,
   err = ensure_connq (sock);
   if (!err)
     {
+      struct timespec noblock = {0, 0};
       struct sock *peer_sock;
 
-      err = connq_listen (sock->listen_queue, sock->flags & SOCK_NONBLOCK,
+      err = connq_listen (sock->listen_queue,
+			  (sock->flags & SOCK_NONBLOCK) ? &noblock : NULL,
 			  &peer_sock);
       if (!err)
 	{
diff --git a/storeio/io.c b/storeio/io.c
index 508df77a..c79f6ba3 100644
--- a/storeio/io.c
+++ b/storeio/io.c
@@ -161,6 +161,15 @@ trivfs_S_io_select (struct trivfs_protid *cred,
   return 0;
 }
 
+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);
+}
+
 /* Truncate file.  */
 error_t
 trivfs_S_file_set_size (struct trivfs_protid *cred,
diff --git a/term/ptyio.c b/term/ptyio.c
index 0f5ddb01..44a215bb 100644
--- a/term/ptyio.c
+++ b/term/ptyio.c
@@ -459,9 +459,10 @@ pty_io_readable (size_t *amt)
 /* Validation has already been done by trivfs_S_io_select. */
 error_t
 pty_io_select (struct trivfs_protid *cred, mach_port_t reply,
-	       int *type)
+	       struct timespec *tsp, int *type)
 {
   int avail = 0;
+  error_t err;
 
   if (*type == 0)
     return 0;
@@ -488,13 +489,18 @@ pty_io_select (struct trivfs_protid *cred, mach_port_t reply,
 	}
 
       ports_interrupt_self_on_port_death (cred, reply);
-
       pty_read_blocked = 1;
-      if (pthread_hurd_cond_wait_np (&pty_select_wakeup, &global_lock))
+      err = pthread_hurd_cond_timedwait_np (&pty_select_wakeup, &global_lock,
+					    tsp);
+      if (err)
 	{
 	  *type = 0;
 	  pthread_mutex_unlock (&global_lock);
-	  return EINTR;
+
+	  if (err == ETIMEDOUT)
+	    err = 0;
+
+	  return err;
 	}
     }
 }
diff --git a/term/term.h b/term/term.h
index f154d4c0..df82b6c9 100644
--- a/term/term.h
+++ b/term/term.h
@@ -386,7 +386,8 @@ error_t pty_io_write (struct trivfs_protid *, char *,
 error_t pty_io_read (struct trivfs_protid *, char **,
 		     mach_msg_type_number_t *, mach_msg_type_number_t);
 error_t pty_io_readable (size_t *);
-error_t pty_io_select (struct trivfs_protid *, mach_port_t, int *);
+error_t pty_io_select (struct trivfs_protid *, mach_port_t,
+		       struct timespec *, int *);
 error_t pty_open_hook (struct trivfs_control *, struct iouser *, int);
 error_t pty_po_create_hook (struct trivfs_peropen *);
 error_t pty_po_destroy_hook (struct trivfs_peropen *);
diff --git a/term/users.c b/term/users.c
index 9fc1dc23..529693e8 100644
--- a/term/users.c
+++ b/term/users.c
@@ -2002,17 +2002,17 @@ trivfs_S_io_async (struct trivfs_protid *cred,
   return 0;
 }
 
-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)
 {
   if (!cred)
     return EOPNOTSUPP;
 
   if (cred->pi.class == pty_class)
-    return pty_io_select (cred, reply, type);
+    return pty_io_select (cred, reply, tsp, type);
 
   if ((cred->po->openmodes & O_READ) == 0)
     *type &= ~SELECT_READ;
@@ -2024,6 +2024,8 @@ trivfs_S_io_select (struct trivfs_protid *cred,
   while (1)
     {
       int available = 0;
+      error_t err = 0;
+
       if ((*type & SELECT_READ) && qsize (inputq))
 	available |= SELECT_READ;
       if ((*type & SELECT_WRITE) && qavail (outputq))
@@ -2032,16 +2034,41 @@ trivfs_S_io_select (struct trivfs_protid *cred,
       if (available == 0)
 	{
 	  ports_interrupt_self_on_port_death (cred, reply);
-	  if (pthread_hurd_cond_wait_np (&select_alert, &global_lock) == 0)
+	  err = pthread_hurd_cond_timedwait_np (&select_alert, &global_lock,
+						tsp);
+	  if (!err)
 	    continue;
 	}
 
       *type = available;
       pthread_mutex_unlock (&global_lock);
-      return available ? 0 : 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);
+}
+
 kern_return_t
 trivfs_S_io_map  (struct trivfs_protid *cred,
 		  mach_port_t reply,
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)