Initial revision

1 files changed, 246 insertions, 0 deletions

diff --git a/libpipe/pipe.c b/libpipe/pipe.c
new file mode 100644
index 00000000..73463acd
--- /dev/null
+++ b/libpipe/pipe.c
@@ -0,0 +1,246 @@
+/* Generic one-way pipes
+
+   Copyright (C) 1995 Free Software Foundation, Inc.
+
+   Written by Miles Bader <miles@gnu.ai.mit.edu>
+
+   This program is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2, or (at
+   your option) any later version.
+
+   This program 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
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
+
+#include <string.h>		/* For bzero() */
+
+#include <mach/time_value.h>
+#include <mach/mach_host.h>
+
+#include "pipe.h"
+
+static inline void
+timestamp (time_value_t *stamp)
+{
+  host_get_time (mach_host_self (), stamp);
+}
+
+/* ---------------------------------------------------------------- */
+
+/* Creates a new pipe of class CLASS and returns it in RESULT.  */
+error_t
+pipe_create (struct pipe_class *class, struct pipe **pipe)
+{
+  struct pipe *new = malloc (sizeof (struct pipe));
+
+  if (new == NULL)
+    return ENOMEM;
+
+  new->refs = 0;
+  new->flags = 0;
+  new->class = class;
+
+  bzero (&new->read_time, sizeof (new->read_time));
+  bzero (&new->write_time, sizeof (new->write_time));
+
+  condition_init (&new->pending_reads);
+  condition_init (&new->pending_selects);
+  mutex_init (&new->lock);
+
+  new->interrupt_seq_num = 0;
+  pq_create (&new->queue);  
+
+  *pipe = new;
+  return 0;
+}
+
+/* Free PIPE and any resources it holds.  */
+void 
+pipe_free (struct pipe *pipe)
+{
+  pq_free (pipe->queue);
+  free (pipe);
+}
+
+/* Wake up all threads waiting on PIPE, which should be locked.  */
+inline void
+pipe_kick (struct pipe *pipe)
+{
+  /* Now wake them all up for the bad news... */
+  condition_broadcast (&pipe->pending_reads);
+  mutex_unlock (&pipe->lock);
+  condition_broadcast (&pipe->pending_selects);
+  mutex_lock (&pipe->lock);	/* Get back the lock on PIPE.  */
+}
+
+/* Discard a reference to PIPE, which should be unlocked, being sure to make
+   users aware of this.  */
+void
+pipe_break (struct pipe *pipe)
+{
+  mutex_lock (&pipe->lock);
+
+  /* As there may be multiple writers on a connectionless socket, we
+     never allow EOF to be signaled on the reader.  */
+  if (! (pipe->class->flags & PIPE_CLASS_CONNECTIONLESS))
+    pipe->flags |= PIPE_BROKEN;
+
+  if (pipe->refs > 1)
+    /* Other references to PIPE besides ours?  Wake 'em up.  */
+    pipe_kick (pipe);
+
+  pipe_release (pipe);
+}
+
+/* Writes up to LEN bytes of DATA, to PIPE, which should be locked, and
+   returns the amount written in AMOUNT.  If present, the information in
+   CONTROL & PORTS is written in a preceding control packet.  If an error is
+   returned, nothing is done.  */
+error_t
+pipe_send (struct pipe *pipe, void *source,
+	   char *data, size_t data_len,
+	   char *control, size_t control_len,
+	   mach_port_t *ports, size_t num_ports,
+	   size_t *amount)
+{
+  error_t err = 0;
+
+  if (pipe->flags & PIPE_BROKEN)
+    return EPIPE;
+
+  if (control || ports)
+    /* Write a control packet.  */
+    {
+      struct packet *control_packet =
+	pq_queue (pipe->queue, PACKET_TYPE_CONTROL, source);
+      if (control_packet == NULL)
+	err = ENOBUFS;
+      else
+	{
+	  err = packet_write (control_packet, control, control_len, NULL);
+	  if (!err)
+	    err = packet_set_ports (control_packet, ports, num_ports);
+	  if (err)
+	    /* Trash CONTROL_PACKET somehow XXX */;
+	}
+    }
+
+  if (!err)
+    err = (*pipe->class->write)(pipe->queue, source, data, data_len, amount);
+
+  if (!err)
+    {
+      timestamp (&pipe->write_time);
+      
+      /* And wakeup anyone that might be interested in it.  */
+      condition_signal (&pipe->pending_reads);
+      mutex_unlock (&pipe->lock);
+
+      mutex_lock (&pipe->lock);	/* Get back the lock on PIPE.  */
+      /* Only wakeup selects if there's still data available.  */
+      if (pipe_is_readable (pipe, 0))
+	{
+	  condition_signal (&pipe->pending_selects);
+	  /* We leave PIPE locked here, assuming the caller will soon unlock
+	     it and allow others access.  */
+	}
+    }
+
+  return err;
+}
+
+/* Reads up to AMOUNT bytes from PIPE, which should be locked, into DATA, and
+   returns the amount read in DATA_LEN.  If NOBLOCK is true, EWOULDBLOCK is
+   returned instead of block when no data is immediately available.  If an
+   error is returned, nothing is done.  If source isn't NULL, the address of
+   the socket from which the data was sent is returned in it; this may be
+   NULL if it wasn't specified by the sender (which is usually the case with
+   connection-oriented protcols).
+
+   If there is control data waiting (before any data), then the behavior
+   depends on whether this is an `ordinary read' (when CONTROL and PORTS are
+   both NULL), in which case any control data is skipped, or a `msg read', in
+   which case the contents of the first control packet is returned (in
+   CONTROL and PORTS), as well as the first data packet following that (if
+   the control packet is followed by another control packet or no packet in
+   this case, a zero length data buffer is returned; the user should be
+   careful to distinguish this case from EOF (when no control or ports data
+   is returned either).  */
+error_t
+pipe_recv (struct pipe *pipe, int noblock, unsigned *flags, void **source,
+	   char **data, size_t *data_len, size_t amount,
+	   char **control, size_t *control_len,
+	   mach_port_t **ports, size_t *num_ports)
+{
+  error_t err;
+  struct packet *packet;
+  struct pq *pq = pipe->queue;
+  /* True if the user isn't asking for any `control' data.  */
+  int data_only = (control == NULL && ports == NULL);
+
+  err = pipe_wait (pipe, noblock, data_only);
+  if (err)
+    return err;
+
+  packet = pq_head (pq, PACKET_TYPE_ANY, 0);
+
+  if (data_only)
+    /* The user doesn't want to know about control info, so skip any...  */
+    while (packet && packet->type == PACKET_TYPE_CONTROL)
+      packet = pq_next (pq, PACKET_TYPE_ANY, 0);
+  else if (packet && packet->type == PACKET_TYPE_CONTROL)
+    /* Read this control packet first, before looking for a data packet. */
+    {
+      void *control_source;
+
+      if (control != NULL)
+	packet_read (packet, control, control_len, packet_readable (packet));
+      if (ports != NULL)
+	/* Copy out the port rights being sent.  */
+	packet_read_ports (packet, ports, num_ports);
+
+      packet_read_source (packet, &control_source);
+      packet = pq_next (pq, PACKET_TYPE_DATA, control_source);
+      if (!packet && source)
+	/* Since there is no data, say where the control data came from.  */
+	*source = control_source;
+      else if (control_source)
+	/* Otherwise be sure to get rid of our reference to the address. */
+	pipe_dealloc_addr (control_source);
+    }
+  else
+    /* No control data... */
+    {
+      if (control_len)
+	*control_len = 0;
+      if (num_ports)
+	*num_ports = 0;
+    }
+
+  if (!err)
+    if (packet)
+      /* Read some data (PACKET must be a data packet at this point).  */
+      {
+	int dq = 1;	/* True if we should dequeue this packet.  */
+
+ 	if (source)
+	  packet_read_source (packet, source);
+	err = (*pipe->class->read)(packet, &dq, flags, data, data_len, amount);
+	if (dq)
+	  pq_dequeue (pq);
+      }
+    else
+      /* Return EOF.  */
+      *data_len = 0;
+
+  if (!err && packet)
+    timestamp (&pipe->read_time);
+
+  return err;
+}