hare

commit 67aeb09b77b99130ffcbe178fe5f9c7c1bf1816b
parent 37b75e9ab17fa380f0b406bc664df1867893c25a
Author: Drew DeVault <sir@cmpwn.com>
Date:   Wed, 20 Oct 2021 11:36:45 +0200

iobus: implement poll

Signed-off-by: Drew DeVault <sir@cmpwn.com>

Diffstat:
M
cmd/iobus/main.ha
 | 
38
++++++++++++++++++++------------------
M
iobus/io_uring/ops.ha
 | 
32
+++++++++++++++++++++++++++++++-
M
scripts/gen-stdlib
 | 
2
+-
M
stdlib.mk
 | 
4
++--

4 files changed, 54 insertions(+), 22 deletions(-)
diff --git a/cmd/iobus/main.ha b/cmd/iobus/main.ha
@@ -5,36 +5,38 @@ use iobus;
 use os;
 use strings;
 use unix::poll;
-use unix::poll::{event};
 
 export fn main() void = {
+	// TODO: It would be nice to have two iobus instances here, one for us
+	// (i.e. polling stdin) and one for the user. However, it does not seem
+	// to be possible to poll an io_uring fd on Linux 5.10. I have written
+	// to the io_uring mailing list for more information.
 	let bus = iobus::new()!;
 	defer iobus::destroy(bus);
 
-	const pollfd = [
-		poll::pollfd {
-			fd = os::stdin_file,
-			events = event::POLLIN,
-			...
-		},
-		poll::pollfd {
-			fd = iobus::busfile(bus),
-			events = event::POLLIN,
-			...
-		},
-	];
+	const in = iobus::register_file(bus, os::stdin_file);
+	let poll = iobus::poll(bus, in, poll::event::POLLIN)!;
+	iobus::enqueue(bus, &poll);
 	fmt::error("> ")!;
 
 	for (true) {
-		let events = poll::poll(pollfd, poll::INDEF)!;
-		if (pollfd[0].revents & event::POLLIN > 0) {
+		const res = match (iobus::dispatch(bus)) {
+		case err: iobus::error =>
+			fmt::fatal("Error dispatching bus: {}",
+				iobus::strerror(err));
+		case res: iobus::result =>
+			yield res;
+		};
+		defer iobus::done(bus, res);
+
+		if (iobus::handleof(res) == &poll) {
+			iobus::endpoll(bus, res)!;
 			if (!readcmd(bus)) {
 				fmt::errorln("exit")!;
 				break;
 			};
-		};
-		if (pollfd[1].revents & event::POLLIN > 0) {
-			void; // TODO
+			poll = iobus::poll(bus, in, poll::event::POLLIN)!;
+			iobus::enqueue(bus, &poll);
 		};
 	};
 };
diff --git a/iobus/io_uring/ops.ha b/iobus/io_uring/ops.ha
@@ -2,7 +2,9 @@ use io;
 use linux::io_uring;
 use net::ip;
 use rt;
-// TODO: Seek to de-duplicate some of the SQE prep code
+use unix::poll;
+
+// TODO: Seek to de-duplicate more of the SQE prep code
 
 fn getsqe(bus: *bus) (*io_uring::sqe | queuefull) = {
 	match (io_uring::get_sqe(&bus.uring)) {
@@ -145,3 +147,31 @@ export fn endaccept(res: result, opts: accept_opts...) (io::file | error) = {
 	};
 	return file;
 };
+
+// Prepares an asynchronous poll operation for a file.
+export fn poll(
+	bus: *bus,
+	file: file,
+	events: poll::event,
+) (handle | queuefull) = {
+	// TODO: Support IORING_POLL_ADD_MULTI
+	let sqe = getsqe(bus)?;
+	let flags = io_uring::flags::NONE;
+	let fd = match (file) {
+	case file: io::file =>
+		yield file: i32;
+	case file: registered_file =>
+		flags |= io_uring::flags::FIXED_FILE;
+		yield file: i32;
+	};
+	io_uring::poll_add(sqe, fd, events: uint, flags);
+	return handle { sqe = sqe, ...  };
+};
+
+export fn endpoll(bus: *bus, res: result) (poll::event | error) = {
+	let handle = handleof(res);
+	assert(handle.sqe.opcode == io_uring::op::POLL_ADD);
+	return io_uring::result(res)?: poll::event;
+};
+
+// TODO: poll_remove
diff --git a/scripts/gen-stdlib b/scripts/gen-stdlib
@@ -578,7 +578,7 @@ iobus_io_uring() {
 		handle.ha \
 		types.ha \
 		ops.ha
-	gen_ssa iobus::io_uring errors io linux::io_uring net::ip
+	gen_ssa iobus::io_uring errors io linux::io_uring net::ip unix::poll
 }
 
 linux() {
diff --git a/stdlib.mk b/stdlib.mk
@@ -848,7 +848,7 @@ stdlib_iobus_io_uring_srcs= \
 	$(STDLIB)/iobus/io_uring/types.ha \
 	$(STDLIB)/iobus/io_uring/ops.ha
 
-$(HARECACHE)/iobus/io_uring/iobus_io_uring.ssa: $(stdlib_iobus_io_uring_srcs) $(stdlib_rt) $(stdlib_errors) $(stdlib_io) $(stdlib_linux_io_uring) $(stdlib_net_ip)
+$(HARECACHE)/iobus/io_uring/iobus_io_uring.ssa: $(stdlib_iobus_io_uring_srcs) $(stdlib_rt) $(stdlib_errors) $(stdlib_io) $(stdlib_linux_io_uring) $(stdlib_net_ip) $(stdlib_unix_poll)
 	@printf 'HAREC \t$@\n'
 	@mkdir -p $(HARECACHE)/iobus/io_uring
 	@HARECACHE=$(HARECACHE) $(HAREC) $(HAREFLAGS) -o $@ -Niobus::io_uring \
@@ -2122,7 +2122,7 @@ testlib_iobus_io_uring_srcs= \
 	$(STDLIB)/iobus/io_uring/types.ha \
 	$(STDLIB)/iobus/io_uring/ops.ha
 
-$(TESTCACHE)/iobus/io_uring/iobus_io_uring.ssa: $(testlib_iobus_io_uring_srcs) $(testlib_rt) $(testlib_errors) $(testlib_io) $(testlib_linux_io_uring) $(testlib_net_ip)
+$(TESTCACHE)/iobus/io_uring/iobus_io_uring.ssa: $(testlib_iobus_io_uring_srcs) $(testlib_rt) $(testlib_errors) $(testlib_io) $(testlib_linux_io_uring) $(testlib_net_ip) $(testlib_unix_poll)
 	@printf 'HAREC \t$@\n'
 	@mkdir -p $(TESTCACHE)/iobus/io_uring
 	@HARECACHE=$(TESTCACHE) $(HAREC) $(TESTHAREFLAGS) -o $@ -Niobus::io_uring \