user /keyboard: handle open()s instantly even if waiting for kb

fixes e.g. `echo */*` in dash

1 files changed, 50 insertions, 16 deletions

diff --git a/src/user/app/init/driver/ps2.c b/src/user/app/init/driver/ps2.c
index 2752238..5470249 100644
--- a/src/user/app/init/driver/ps2.c
+++ b/src/user/app/init/driver/ps2.c
@@ -1,10 +1,12 @@
 #include "driver.h"
+#include <assert.h>
 #include <camellia/compat.h>
 #include <camellia/syscalls.h>
 #include <errno.h>
 #include <shared/ring.h>
 #include <stdbool.h>
 #include <stdlib.h>
+#include <thread.h>
 
 
 static const char keymap_lower[] = {
@@ -51,36 +53,68 @@ static void parse_scancode(uint8_t s) {
 	if (down && c) ring_put1b((void*)&backlog, c);
 }
 
-static void main_loop(void) {
+
+/** Is a thread waiting for /kdev/ps2/kb? */
+static volatile bool blocked = false;
+/* for use in read_thread */
+static hid_t rt_reqh;
+static size_t rt_cap;
+
+static void read_thread(void *unused) {
+	char buf[512];
+	(void)unused;
+
+	assert(blocked);
+	while (ring_used((void*)&backlog) == 0) {
+		/* read raw input until we have something to output */
+		int len = _sys_read(fd, buf, sizeof buf, 0);
+		if (len == 0) break;
+		for (int i = 0; i < len; i++)
+			parse_scancode(buf[i]);
+	}
+	if (ring_used((void*)&backlog) > 0) {
+		int ret = ring_get((void*)&backlog, buf, rt_cap);
+		_sys_fs_respond(rt_reqh, buf, ret, 0);
+	} else {
+		_sys_fs_respond(rt_reqh, 0, -EGENERIC, 0);
+	}
+	blocked = false;
+}
+
+static void fs_loop(void) {
 	static char buf[512];
-	struct ufs_request res;
 	int ret;
-	while (!c0_fs_wait(buf, sizeof buf, &res)) {
-		// TODO don't hang on ps2 reads
+	for (;;) {
+		struct ufs_request res;
+		hid_t reqh = _sys_fs_wait(buf, sizeof buf, &res);
+		if (reqh < 0) return;
 
 		switch (res.op) {
 			case VFSOP_OPEN:
 				if (res.len == 0) {
-					c0_fs_respond(NULL, 1, 0);
+					_sys_fs_respond(reqh, NULL, 1, 0);
 				} else {
-					c0_fs_respond(NULL, -ENOENT, 0);
+					_sys_fs_respond(reqh, NULL, -ENOENT, 0);
 				}
 				break;
 
 			case VFSOP_READ:
-				while (ring_used((void*)&backlog) == 0) {
-					/* read raw input until we have something to output */
-					int len = _sys_read(fd, buf, sizeof buf, 0);
-					if (len == 0) break;
-					for (int i = 0; i < len; i++)
-						parse_scancode(buf[i]);
+				if (blocked) {
+					_sys_fs_respond(reqh, NULL, -EAGAIN, 0);
+					break;
+				} else if (ring_used((void*)&backlog) > 0) {
+					ret = ring_get((void*)&backlog, buf, res.capacity);
+					_sys_fs_respond(reqh, buf, ret, 0);
+				} else {
+					blocked = true;
+					rt_reqh = reqh;
+					rt_cap = res.capacity;
+					thread_create(0, read_thread, 0);
 				}
-				ret = ring_get((void*)&backlog, buf, res.capacity);
-				c0_fs_respond(buf, ret, 0);
 				break;
 
 			default:
-				c0_fs_respond(NULL, -1, 0);
+				_sys_fs_respond(reqh, NULL, -1, 0);
 				break;
 		}
 	}
@@ -90,6 +124,6 @@ void ps2_drv(void) {
 	fd = _sys_open("/kdev/ps2/kb", 12, 0);
 	if (fd < 0) exit(1);
 
-	main_loop();
+	fs_loop();
 	exit(0);
 }