From 2398dd9b805fb97b5fcf469930dc8801f677d45f Mon Sep 17 00:00:00 2001
From: Matheus <matheusuky@gmail.com>
Date: Sun, 9 Jul 2023 18:11:53 -0300
Subject: [PATCH] poll: timeout

---
 kernel-src/include/kernel/poll.h |  2 +-
 kernel-src/io/poll.c             | 29 ++++++++++++++++++++++++++++-
 kernel-src/sys/syscalls/poll.c   |  8 ++------
 3 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/kernel-src/include/kernel/poll.h b/kernel-src/include/kernel/poll.h
index 6abbf7fb..bc32ef26 100644
--- a/kernel-src/include/kernel/poll.h
+++ b/kernel-src/include/kernel/poll.h
@@ -36,7 +36,7 @@ typedef struct polldata {
 int poll_initdesc(polldesc_t *, size_t size);
 void poll_add(pollheader_t *, polldata_t *, int events);
 void poll_leave(polldesc_t *);
-int poll_dowait(polldesc_t *);
+int poll_dowait(polldesc_t *, size_t ustimeout);
 void poll_event(pollheader_t *, int events);
 void poll_destroydesc(polldesc_t *);
 
diff --git a/kernel-src/io/poll.c b/kernel-src/io/poll.c
index a1cb5bf6..b276f6b8 100644
--- a/kernel-src/io/poll.c
+++ b/kernel-src/io/poll.c
@@ -64,7 +64,20 @@ void poll_leave(polldesc_t *desc) {
 	}
 }
 
-int poll_dowait(polldesc_t *desc) {
+static void timeout(context_t *, dpcarg_t arg) {
+	polldesc_t *desc = arg;
+
+	MUTEX_TRY(&desc->eventlock);
+
+	if (spinlock_try(&desc->lock))
+		sched_wakeup(desc->thread, 1);
+
+	MUTEX_RELEASE(&desc->eventlock);
+}
+
+int poll_dowait(polldesc_t *desc, size_t ustimeout) {
+	timerentry_t sleepentry = {0};
+
 	MUTEX_ACQUIRE(&desc->eventlock, false);
 	if (desc->event) {
 		MUTEX_RELEASE(&desc->eventlock);
@@ -72,12 +85,26 @@ int poll_dowait(polldesc_t *desc) {
 	}
 
 	sched_preparesleep(true);
+
+	if (ustimeout != 0) {
+		sched_targetcpu(_cpu());
+		timer_insert(_cpu()->timer, &sleepentry, timeout, desc, ustimeout, false);
+	}
+
 	spinlock_release(&desc->lock);
 	MUTEX_RELEASE(&desc->eventlock);
 	int ret = sched_yield();
 	// on return, the desc lock is REQUIRED to be left locked by the poll_event function.
 	// XXX interruptible wait breaks this
 	__assert(spinlock_try(&desc->lock) == false);
+
+	if (ustimeout != 0 && ret != 1) {
+		timer_remove(_cpu()->timer, &sleepentry);
+		sched_targetcpu(NULL);
+	}
+
+	ret = ret == 1 ? 0 : ret;
+
 	return ret;
 }
 
diff --git a/kernel-src/sys/syscalls/poll.c b/kernel-src/sys/syscalls/poll.c
index 0df366f6..0b8ae59b 100644
--- a/kernel-src/sys/syscalls/poll.c
+++ b/kernel-src/sys/syscalls/poll.c
@@ -16,9 +16,6 @@ syscallret_t syscall_poll(context_t *, pollfd_t *fds, size_t nfds, int timeoutms
 		.ret = -1
 	};
 
-	// timeouts are not supported yet
-	__assert(timeoutms <= 0);
-
 	if ((void *)fds > USERSPACE_END) {
 		ret.errno = EFAULT;
 		return ret;
@@ -60,9 +57,8 @@ syscallret_t syscall_poll(context_t *, pollfd_t *fds, size_t nfds, int timeoutms
 	}
 
 	if (eventcount == 0 && timeoutms != 0) {
-		// TODO timeout
-		ret.errno = poll_dowait(&desc);
-		if (ret.errno == 0) {
+		ret.errno = poll_dowait(&desc, (timeoutms == -1 ? 0 : timeoutms) * 1000);
+		if (ret.errno == 0 && desc.event) {
 			int fd = ((uintptr_t)desc.event - (uintptr_t)desc.data) / sizeof(pollfd_t);
 			fdsbuff[fd].revents = desc.data[fd].revents;
 			eventcount = 1;