Initial revision

src/libthread/ioproc.c

@@ -0,0 +1,74 @@
+#include "threadimpl.h"
+
+enum
+{
+	STACK = 8192,
+};
+
+void
+iointerrupt(Ioproc *io)
+{
+	if(!io->inuse)
+		return;
+	threadint(io->tid);
+}
+
+static void
+xioproc(void *a)
+{
+	Ioproc *io, *x;
+	io = a;
+	/*
+	 * first recvp acquires the ioproc.
+	 * second tells us that the data is ready.
+	 */
+	for(;;){
+		while(recv(io->c, &x) == -1)
+			;
+		if(x == 0)	/* our cue to leave */
+			break;
+		assert(x == io);
+
+		/* caller is now committed -- even if interrupted he'll return */
+		while(recv(io->creply, &x) == -1)
+			;
+		if(x == 0)	/* caller backed out */
+			continue;
+		assert(x == io);
+
+		io->ret = io->op(&io->arg);
+		if(io->ret < 0)
+			rerrstr(io->err, sizeof io->err);
+		while(send(io->creply, &io) == -1)
+			;
+		while(recv(io->creply, &x) == -1)
+			;
+	}
+}
+
+Ioproc*
+ioproc(void)
+{
+	Ioproc *io;
+
+	io = mallocz(sizeof(*io), 1);
+	if(io == nil)
+		sysfatal("ioproc malloc: %r");
+	io->c = chancreate(sizeof(void*), 0);
+	io->creply = chancreate(sizeof(void*), 0);
+	io->tid = proccreate(xioproc, io, STACK);
+	return io;
+}
+
+void
+closeioproc(Ioproc *io)
+{
+	if(io == nil)
+		return;
+	iointerrupt(io);
+	while(send(io->c, 0) == -1)
+		;
+	chanfree(io->c);
+	chanfree(io->creply);
+	free(io);
+}