Merge pull request #5534 from Karlson2k/fix_vfs_and_emu_01

Better emulate system read() and fread() functions, fixes #15490

4 files changed, 27 insertions, 11 deletions

diff --git a/xbmc/cores/DllLoader/exports/emu_msvcrt.cpp b/xbmc/cores/DllLoader/exports/emu_msvcrt.cpp
index 5bde82e71e..58474d25d3 100644
--- a/xbmc/cores/DllLoader/exports/emu_msvcrt.cpp
+++ b/xbmc/cores/DllLoader/exports/emu_msvcrt.cpp
@@ -530,7 +530,7 @@ extern "C"
     if (bWrite)
       bResult = pFile->OpenForWrite(CUtil::ValidatePath(str), bOverwrite);
     else
-      bResult = pFile->Open(CUtil::ValidatePath(str));
+      bResult = pFile->Open(CUtil::ValidatePath(str), READ_TRUNCATED);
 
     if (bResult)
     {
diff --git a/xbmc/filesystem/File.cpp b/xbmc/filesystem/File.cpp
index 0468b79b2c..c4ac83372e 100644
--- a/xbmc/filesystem/File.cpp
+++ b/xbmc/filesystem/File.cpp
@@ -497,7 +497,9 @@ int CFile::Stat(const CURL& file, struct __stat64* buffer)
 
 ssize_t CFile::Read(void *lpBuf, size_t uiBufSize)
 {
-  if (!m_pFile || !lpBuf)
+  if (!m_pFile)
+    return -1;
+  if (lpBuf == NULL && uiBufSize != 0)
     return -1;
 
   if (uiBufSize > SSIZE_MAX)
@@ -743,7 +745,9 @@ bool CFile::ReadString(char *szLine, int iLineLength)
 
 ssize_t CFile::Write(const void* lpBuf, size_t uiBufSize)
 {
-  if (!m_pFile || !lpBuf)
+  if (!m_pFile)
+    return -1;
+  if (lpBuf == NULL && uiBufSize != 0)
     return -1;
 
   try
diff --git a/xbmc/filesystem/posix/PosixFile.cpp b/xbmc/filesystem/posix/PosixFile.cpp
index b59e7dc957..35909a01c8 100644
--- a/xbmc/filesystem/posix/PosixFile.cpp
+++ b/xbmc/filesystem/posix/PosixFile.cpp
@@ -113,10 +113,13 @@ void CPosixFile::Close()
 
 ssize_t CPosixFile::Read(void* lpBuf, size_t uiBufSize)
 {
-  assert(lpBuf != NULL);
-  if (m_fd < 0 || !lpBuf)
+  if (m_fd < 0)
     return -1;
   
+  assert(lpBuf != NULL || uiBufSize == 0);
+  if (lpBuf == NULL && uiBufSize != 0)
+    return -1;
+
   if (uiBufSize > SSIZE_MAX)
     uiBufSize = SSIZE_MAX;
   
@@ -152,8 +155,11 @@ ssize_t CPosixFile::Read(void* lpBuf, size_t uiBufSize)
 
 ssize_t CPosixFile::Write(const void* lpBuf, size_t uiBufSize)
 {
-  assert(lpBuf != NULL);
-  if (m_fd < 0 || !m_allowWrite || !lpBuf)
+  if (m_fd < 0)
+    return -1;
+
+  assert(lpBuf != NULL || uiBufSize == 0);
+  if ((lpBuf == NULL && uiBufSize != 0) || !m_allowWrite)
     return -1;
 
   if (uiBufSize > SSIZE_MAX)
diff --git a/xbmc/filesystem/win32/Win32File.cpp b/xbmc/filesystem/win32/Win32File.cpp
index 7b927a007d..dfc5babe6b 100644
--- a/xbmc/filesystem/win32/Win32File.cpp
+++ b/xbmc/filesystem/win32/Win32File.cpp
@@ -173,8 +173,11 @@ void CWin32File::Close()
 
 ssize_t CWin32File::Read(void* lpBuf, size_t uiBufSize)
 {
-  assert(lpBuf != NULL);
-  if (m_hFile == INVALID_HANDLE_VALUE || !lpBuf)
+  if (m_hFile == INVALID_HANDLE_VALUE)
+    return -1;
+
+  assert(lpBuf != NULL || uiBufSize == 0);
+  if (lpBuf == NULL && uiBufSize != 0)
     return -1;
 
   if (uiBufSize > SSIZE_MAX)
@@ -211,8 +214,11 @@ ssize_t CWin32File::Read(void* lpBuf, size_t uiBufSize)
 
 ssize_t CWin32File::Write(const void* lpBuf, size_t uiBufSize)
 {
-  assert(lpBuf != NULL);
-  if (m_hFile == INVALID_HANDLE_VALUE || !lpBuf)
+  if (m_hFile == INVALID_HANDLE_VALUE)
+    return -1;
+
+  assert(lpBuf != NULL || uiBufSize == 0);
+  if (lpBuf == NULL && uiBufSize != 0)
     return -1;
 
   if (!m_allowWrite)