From a67d2d4364280ffa21f8054afde91af027f4214b Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris+github@qwirx.com>
Date: Sat, 10 Mar 2007 17:32:44 +0000
Subject: Fix handling of O_EXCL to behave just like Unix, not abused to lock
 files.

Add a new constant which specifies that files are to be locked open.

(refs #3, merges [1288])
---
 lib/win32/emu.cpp | 18 ++++++++++++------
 lib/win32/emu.h   |  3 +++
 2 files changed, 15 insertions(+), 6 deletions(-)

(limited to 'lib')

diff --git a/lib/win32/emu.cpp b/lib/win32/emu.cpp
index b201a9e0..3de83517 100644
--- a/lib/win32/emu.cpp
+++ b/lib/win32/emu.cpp
@@ -541,30 +541,37 @@ HANDLE openfile(const char *pFileName, int flags, int mode)
 
 	// flags could be O_WRONLY | O_CREAT | O_RDONLY
 	DWORD createDisposition = OPEN_EXISTING;
-	DWORD shareMode = FILE_SHARE_READ;
-	DWORD accessRights = FILE_READ_ATTRIBUTES | FILE_LIST_DIRECTORY | FILE_READ_EA;
+	DWORD shareMode = FILE_SHARE_READ | FILE_SHARE_WRITE 
+		| FILE_SHARE_DELETE;
+	DWORD accessRights = FILE_READ_ATTRIBUTES | FILE_LIST_DIRECTORY 
+		| FILE_READ_EA;
 
 	if (flags & O_WRONLY)
 	{
 		accessRights = FILE_WRITE_DATA;
-		shareMode = FILE_SHARE_WRITE;
 	}
 	else if (flags & O_RDWR)
 	{
 		accessRights |= FILE_WRITE_ATTRIBUTES 
 			| FILE_WRITE_DATA | FILE_WRITE_EA;
-		shareMode |= FILE_SHARE_WRITE;
 	}
 
 	if (flags & O_CREAT)
 	{
 		createDisposition = OPEN_ALWAYS;
 	}
+
 	if (flags & O_TRUNC)
 	{
 		createDisposition = CREATE_ALWAYS;
 	}
-	if (flags & O_EXCL)
+
+	if ((flags & O_CREAT) && (flags & O_EXCL))
+	{
+		createDisposition = CREATE_NEW;
+	}
+
+	if (flags & O_LOCK)
 	{
 		shareMode = 0;
 	}
@@ -573,7 +580,6 @@ HANDLE openfile(const char *pFileName, int flags, int mode)
 	if (flags & O_TEMPORARY)
 	{
 		winFlags  |= FILE_FLAG_DELETE_ON_CLOSE;
-		shareMode |= FILE_SHARE_DELETE;
 	}
 
 	HANDLE hdir = CreateFileW(pBuffer, 
diff --git a/lib/win32/emu.h b/lib/win32/emu.h
index 5b3e2280..0612e441 100644
--- a/lib/win32/emu.h
+++ b/lib/win32/emu.h
@@ -290,6 +290,9 @@ DIR *opendir(const char *name);
 struct dirent *readdir(DIR *dp);
 int closedir(DIR *dp);
 
+// local constant to open file exclusively without shared access
+#define O_LOCK 0x10000
+
 HANDLE openfile(const char *filename, int flags, int mode);
 
 #define LOG_INFO 6
-- 
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