1 files changed, 30 insertions, 9 deletions

diff --git a/src/kernel/pipe.c b/src/kernel/pipe.c
index 8afd359..34cb263 100644
--- a/src/kernel/pipe.c
+++ b/src/kernel/pipe.c
@@ -3,29 +3,41 @@
 #include <kernel/pipe.h>
 #include <kernel/util.h>
 
-void pipe_joinqueue(struct handle *h, bool wants_write,
+bool pipe_joinqueue(struct handle *h, bool wants_write,
 		struct process *proc, void __user *pbuf, size_t pbuflen)
 {
-	struct process **slot = wants_write ? &h->pipe.reader : &h->pipe.writer;
-	if (*slot) {
-		assert((*slot)->state == PS_WAITS4PIPE);
+	assert(h && h->type == HANDLE_PIPE);
+	if (wants_write == h->pipe.write_end) return false;
+	if (!h->pipe.sister) return false;
+	if (h->pipe.queued) {
+		assert(h->pipe.queued->state == PS_WAITS4PIPE);
 		panic_unimplemented();
 	}
 
 	process_transition(proc, PS_WAITS4PIPE);
-	*slot = proc;
+	h->pipe.queued = proc;
 	proc->waits4pipe.pipe = h;
 	proc->waits4pipe.buf = pbuf;
 	proc->waits4pipe.len = pbuflen;
+	return true;
 }
 
 void pipe_trytransfer(struct handle *h) {
-	struct process *rdr = h->pipe.reader, *wtr = h->pipe.writer;
+	struct process *rdr, *wtr;
 	int len;
+	assert(h);
+	if (!h->pipe.sister) {
+		assert(!h->pipe.queued);
+		return;
+	}
+
+	rdr = h->pipe.write_end ? h->pipe.sister->pipe.queued : h->pipe.queued;
+	wtr = h->pipe.write_end ? h->pipe.queued : h->pipe.sister->pipe.queued;
+
 	if (!(rdr && wtr)) return;
 	assert(rdr->state == PS_WAITS4PIPE);
 	assert(wtr->state == PS_WAITS4PIPE);
-	
+
 	len = min(rdr->waits4pipe.len, wtr->waits4pipe.len);
 
 	if (!virt_cpy(
@@ -36,8 +48,17 @@ void pipe_trytransfer(struct handle *h) {
 	}
 	process_transition(rdr, PS_RUNNING);
 	process_transition(wtr, PS_RUNNING);
-	h->pipe.reader = NULL;
-	h->pipe.writer = NULL;
+	h->pipe.queued = NULL;
+	h->pipe.sister->pipe.queued = NULL;
 	regs_savereturn(&rdr->regs, len);
 	regs_savereturn(&wtr->regs, len);
 }
+
+void pipe_invalidate_end(struct handle *h) {
+	struct process *p = h->pipe.queued;
+	if (p) {
+		process_transition(p, PS_RUNNING);
+		regs_savereturn(&p->regs, -1);
+	}
+	h->pipe.queued = NULL;
+}