From 665e6f17822fd010d16005cb7f64bf02245462cb Mon Sep 17 00:00:00 2001
From: David <David.Samir.WD@gmail.com>
Date: Tue, 13 Oct 2026 02:40:04 +0400
Subject: [PATCH] fix(libkernel): fill every buffer of readv from a pipe on
 Windows

---
 core/libs/prx/libkernel/File/src/Stdio.cpp | 8 +++++++-
 core/libs/tests/GuestFileVector.cpp        | 9 +++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/core/libs/prx/libkernel/File/src/Stdio.cpp b/core/libs/prx/libkernel/File/src/Stdio.cpp
index 71550eb1c..2855e6194 100644
--- a/core/libs/prx/libkernel/File/src/Stdio.cpp
+++ b/core/libs/prx/libkernel/File/src/Stdio.cpp
@@ -218,6 +218,12 @@ static bool NativeIsDisk(int descriptor) {
     const auto handle = reinterpret_cast<HANDLE>(::_get_osfhandle(descriptor));
     return handle != INVALID_HANDLE_VALUE && ::GetFileType(handle) == FILE_TYPE_DISK;
 }
+static bool NativePipeHasData(int descriptor) {
+    const auto handle = reinterpret_cast<HANDLE>(::_get_osfhandle(descriptor));
+    DWORD available = 0;
+    return handle != INVALID_HANDLE_VALUE && ::GetFileType(handle) == FILE_TYPE_PIPE
+        && ::PeekNamedPipe(handle, nullptr, 0, nullptr, &available, nullptr) && available != 0;
+}
 static std::int64_t NativePread(int descriptor, void* buf, std::size_t nbytes, std::int64_t offset) {
     return NativePositioned_nid_no_patch(descriptor, buf, nbytes, offset, false);
 }
@@ -1003,7 +1009,7 @@ static std::int64_t TransferIovecs(int d, const KernelIovec* iov, int iovcnt, co
             if (result < 0) return done != 0 ? done : SceErrorFromErrno(errno);
             done += result;
             position += static_cast<std::size_t>(result);
-            if (static_cast<std::size_t>(result) < chunk || !whole) return done;
+            if (static_cast<std::size_t>(result) < chunk || (!whole && !NativePipeHasData(d))) return done;
         }
     }
     return done;
diff --git a/core/libs/tests/GuestFileVector.cpp b/core/libs/tests/GuestFileVector.cpp
index 370be6be8..eda9297d8 100644
--- a/core/libs/tests/GuestFileVector.cpp
+++ b/core/libs/tests/GuestFileVector.cpp
@@ -206,6 +206,15 @@ int main() {
     Require(sceKernelWritev(ends[1], message, 1) == 3);
     Require(sceKernelReadv(ends[0], reads, 2) == 3);
     Require(std::memcmp(first, "xyz", 3) == 0);
+    char stuvw[] = "stuvw";
+    GuestIovec longer[1] = {{stuvw, 5}};
+    Require(sceKernelWritev(ends[1], longer, 1) == 5);
+    Require(sceKernelReadv(ends[0], reads, 2) == 5);
+    Require(std::memcmp(first, "stu", 3) == 0 && std::memcmp(second, "vw", 2) == 0);
+    Require(sceKernelWritev(ends[1], longer, 1) == 5 && sceKernelWritev(ends[1], longer, 1) == 5);
+    Require(readv_nid_postfix(ends[0], reads, 2) == 7);
+    Require(std::memcmp(first, "stu", 3) == 0 && std::memcmp(second, "vwst", 4) == 0);
+    Require(sceKernelReadv(ends[0], reads, 2) == 3 && std::memcmp(first, "uvw", 3) == 0);
     Require(sceKernelPreadv(ends[0], reads, 2, 0) == ErrorEspipe);
     Require(sceKernelPwritev(ends[1], message, 1, 0) == ErrorEspipe);
 #ifndef _WIN32