From 942b5945d1ec288c826656e2ae391aa73ebd816c Mon Sep 17 00:00:00 2001
From: Hussein Kadhim <husseinkad.dev@gmail.com>
Date: Sun, 11 Oct 2026 19:58:37 +0300
Subject: [PATCH] fix(libkernel): leave the remaining time untouched when
 nanosleep completes

FreeBSD's kern_clock_nanosleep writes the remaining time only when the sleep is cut short. A completed sleep zeroed rmtp, so nanosleep(&ts, &ts) in a polling loop slept zero time from the second call on.
---
 core/libs/prx/libkernel/Time/Time.cpp | 10 +++-------
 core/libs/tests/GuestNanosleep.cpp    | 20 ++++++++++++++++++++
 2 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/core/libs/prx/libkernel/Time/Time.cpp b/core/libs/prx/libkernel/Time/Time.cpp
index 581e81bb5..adf0e99e4 100644
--- a/core/libs/prx/libkernel/Time/Time.cpp
+++ b/core/libs/prx/libkernel/Time/Time.cpp
@@ -251,7 +251,7 @@ int APS5_VABI sceKernelUsleep_nid_postfix(KernelUseconds microseconds) {
     return 0;
 }
 
-static int SleepForRequest(const KernelTimespec* rqtp, KernelTimespec* rmtp) {
+static int SleepForRequest(const KernelTimespec* rqtp) {
     constexpr int guestFault = 14;
     constexpr int guestInvalid = 22;
     if (rqtp == nullptr) return guestFault;
@@ -260,20 +260,16 @@ static int SleepForRequest(const KernelTimespec* rqtp, KernelTimespec* rmtp) {
         CancellableSleep(static_cast<std::uint64_t>(rqtp->tv_sec) * 1000000000ULL +
                          static_cast<std::uint64_t>(rqtp->tv_nsec));
     }
-    if (rmtp != nullptr) {
-        rmtp->tv_sec = 0;
-        rmtp->tv_nsec = 0;
-    }
     return 0;
 }
 
 int APS5_VABI sceKernelNanosleep(const KernelTimespec* rqtp, KernelTimespec* rmtp) {
-    const int error = SleepForRequest(rqtp, rmtp);
+    const int error = SleepForRequest(rqtp);
     return error == 0 ? 0 : SceKernelError(error);
 }
 
 int APS5_VABI nanosleep_nid_postfix(const KernelTimespec* rqtp, KernelTimespec* rmtp) {
-    const int error = SleepForRequest(rqtp, rmtp);
+    const int error = SleepForRequest(rqtp);
     if (error == 0) return 0;
     *__error_nid_postfix() = error;
     return -1;
diff --git a/core/libs/tests/GuestNanosleep.cpp b/core/libs/tests/GuestNanosleep.cpp
index db2e4ee8b..c97b6c1f1 100644
--- a/core/libs/tests/GuestNanosleep.cpp
+++ b/core/libs/tests/GuestNanosleep.cpp
@@ -85,6 +85,22 @@ static void SleepsForTheRequest(Nanosleep sleep) {
     Require(MonotonicNanos() - start >= SLEEP_NANOS - EARLY_WAKE_MARGIN_NANOS);
 }
 
+static void CompletedSleepLeavesTheRemainingTimeAlone(Nanosleep sleep) {
+    const KernelTimespec request{0, NANOS_PER_MILLISECOND};
+    KernelTimespec remaining{7, 9};
+    Require(sleep(&request, &remaining) == SCE_OK);
+    Require(remaining.tv_sec == 7 && remaining.tv_nsec == 9);
+    KernelTimespec shared = request;
+    for (int i = 0; i < 3; ++i) {
+        Require(sleep(&shared, &shared) == SCE_OK);
+        Require(shared.tv_sec == request.tv_sec && shared.tv_nsec == request.tv_nsec);
+    }
+    const KernelTimespec invalid{0, NANOS_PER_SECOND};
+    remaining = {7, 9};
+    Require(sleep(&invalid, &remaining) != SCE_OK);
+    Require(remaining.tv_sec == 7 && remaining.tv_nsec == 9);
+}
+
 int main() {
     PosixRejectsInvalidRequests(nanosleep_nid_postfix);
     PosixRejectsInvalidRequests(_nanosleep_nid_postfix);
@@ -97,4 +113,8 @@ int main() {
     SleepsForTheRequest(nanosleep_nid_postfix);
     SleepsForTheRequest(_nanosleep_nid_postfix);
     SleepsForTheRequest(sceKernelNanosleep);
+
+    CompletedSleepLeavesTheRemainingTimeAlone(nanosleep_nid_postfix);
+    CompletedSleepLeavesTheRemainingTimeAlone(_nanosleep_nid_postfix);
+    CompletedSleepLeavesTheRemainingTimeAlone(sceKernelNanosleep);
 }