From 88094c48ae93c9894383bc91f03b73b827909fd1 Mon Sep 17 00:00:00 2001
From: Jamie Reece Wilson <me@reece.sx>
Date: Fri, 20 Oct 2023 11:37:52 +0100
Subject: [PATCH] [*] Harden pipe reads under FS streams

---
 Source/IO/FS/FileStream.NT.cpp   | 26 ++++++++++++----
 Source/IO/FS/FileStream.Unix.cpp | 51 ++++++++++++++++++++++----------
 2 files changed, 56 insertions(+), 21 deletions(-)

diff --git a/Source/IO/FS/FileStream.NT.cpp b/Source/IO/FS/FileStream.NT.cpp
index 1228664c..7d56f562 100644
--- a/Source/IO/FS/FileStream.NT.cpp
+++ b/Source/IO/FS/FileStream.NT.cpp
@@ -145,13 +145,15 @@ namespace Aurora::IO::FS
     {
         OVERLAPPED overlapped {};
         AuUInt64 uOffset {};
+        
+        parameters.outVariable = 0;
 
         if (!this->pHandle_)
         {
             SysPushErrorUninitialized();
             return 0;
         }
-
+        
         auto hHandle = this->GetWin32Handle(true);
         HANDLE hEventHandle { INVALID_HANDLE_VALUE };
 
@@ -161,6 +163,22 @@ namespace Aurora::IO::FS
             return {};
         }
 
+        AuUInt64 uLength = parameters.length;
+        if (this->pHandle_->IsPipe())
+        {
+            DWORD uAvail {};
+            if (!PeekNamedPipe(hHandle, NULL, NULL, NULL, &uAvail, NULL))
+            {
+                return false;
+            }
+
+            uLength = AuMin(uLength, uAvail);
+            if (!uLength)
+            {
+                return true;
+            }
+        }
+
         bool bIsAsync = this->pHandle_->IsAsync();
         if (bIsAsync)
         {
@@ -172,9 +190,6 @@ namespace Aurora::IO::FS
             }
         }
 
-        parameters.outVariable = 0;
-
-        AuUInt64 uLength = parameters.length;
         while (uLength)
         {
             DWORD read {};
@@ -247,6 +262,8 @@ namespace Aurora::IO::FS
     {
         OVERLAPPED overlapped {};
         AuUInt64 uOffset {};
+        
+        parameters.outVariable = 0;
 
         auto optHandle = this->GetHandle()->GetOSWriteHandleSafe();
         if (!optHandle)
@@ -275,7 +292,6 @@ namespace Aurora::IO::FS
                 return false;
             }
         }
-        parameters.outVariable = 0;
 
         AuUInt64 uLength = parameters.length;
         while (uLength)
diff --git a/Source/IO/FS/FileStream.Unix.cpp b/Source/IO/FS/FileStream.Unix.cpp
index 55267f1c..f940e16a 100755
--- a/Source/IO/FS/FileStream.Unix.cpp
+++ b/Source/IO/FS/FileStream.Unix.cpp
@@ -15,6 +15,7 @@
 #include <sys/types.h>
 #include <unistd.h>
 #include <fcntl.h>
+#include <sys/ioctl.h>
 
 #if !defined(_AURUNTIME_GENERICFILESTREAM)
 
@@ -237,7 +238,6 @@ namespace Aurora::IO::FS
         
         parameters.outVariable = 0;
 	
-
         if (!this->pHandle_)
         {
             SysPushErrorUninitialized();
@@ -251,30 +251,49 @@ namespace Aurora::IO::FS
             return 0;
         }
 
-        auto length = parameters.length;
-        AuUInt offset {0};
-        while (length)
+        AuUInt uOffset {};
+        AuUInt64 uLength = parameters.length;
+
+        if (this->pHandle_->IsPipe())
         {
-            AuUInt32 read;
-
-            int blockSize = AuMin(kFileCopyBlock, length);
-
-            if (!PosixRead(fd, &reinterpret_cast<char *>(parameters.ptr)[offset], blockSize, &read))
+        #if defined(FIONREAD)
+            int available {};
+            if (::ioctl(fd, FIONREAD, &available) < 0)
             {
-                SysPushErrorNested("File Error: {}", path_);
+                return 0;
+            }
+
+            uLength = AuMin(uLength, available);
+            if (!uLength)
+            {
+                return 0;
+            }
+        #endif
+        }
+
+        while (uLength)
+        {
+            AuUInt32 uRead;
+
+            if (!PosixRead(fd,
+                           &reinterpret_cast<char *>(parameters.ptr)[uOffset],
+                           AuMin(kFileCopyBlock, uLength),
+                           &uRead))
+            {
+                SysPushErrorNested("File Error: {}", this->path_);
                 break;
             }
             
-            if (read == 0)
+            if (uRead == 0)
             {
                 break;
             }
 
-            offset += read;
-            length -= read;
+            uOffset += uRead;
+            uLength -= uRead;
         }
         
-        parameters.outVariable = offset;
+        parameters.outVariable = uOffset;
         return true;
     }
     
@@ -282,6 +301,8 @@ namespace Aurora::IO::FS
     {
         AU_LOCK_GUARD(this->spinlock_);
 
+        parameters.outVariable = 0;
+
         if (!this->pHandle_)
         {
             SysPushErrorUninitialized();
@@ -295,8 +316,6 @@ namespace Aurora::IO::FS
             return 0;
         }
 
-        parameters.outVariable = 0;
-
         AuUInt length = parameters.length;
         AuUInt offset {0};
         while (length)