Allow unlink/rename of files open by another process on Win32, using a

special Win32 open flag FILE_SHARE_DELETE.

Claudio Natoli

1 files changed, 97 insertions, 0 deletions

diff --git a/src/port/open.c b/src/port/open.c
new file mode 100644
index 00000000000..ccd2a15b1de
--- /dev/null
+++ b/src/port/open.c
@@ -0,0 +1,97 @@
+/*-------------------------------------------------------------------------
+ *
+ * open.c
+ *	   Win32 open() replacement
+ *
+ *
+ * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
+ *
+ * $PostgreSQL: pgsql/src/port/open.c,v 1.1 2004/03/24 03:54:16 momjian Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#ifdef WIN32
+
+#include <windows.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <assert.h>
+
+int openFlagsToCreateFileFlags(int openFlags)
+{
+	switch (openFlags & (O_CREAT|O_TRUNC|O_EXCL))
+	{
+		case 0:
+		case O_EXCL:	return OPEN_EXISTING;
+
+		case O_CREAT:	return OPEN_ALWAYS;
+
+		case O_TRUNC:
+		case O_TRUNC|O_EXCL:	return TRUNCATE_EXISTING;
+
+		case O_CREAT|O_TRUNC:	return CREATE_ALWAYS;
+
+		case O_CREAT|O_EXCL:
+		case O_CREAT|O_TRUNC|O_EXCL:	return CREATE_NEW;
+	}
+
+	/* will never get here */
+	return 0;
+}
+
+/*
+ *   - file attribute setting, based on fileMode?
+ *   - handle other flags? (eg FILE_FLAG_NO_BUFFERING/FILE_FLAG_WRITE_THROUGH)
+ */
+int win32_open(const char* fileName, int fileFlags, ...)
+{
+	int fd;
+	HANDLE h;
+	SECURITY_ATTRIBUTES sa;
+
+	/* Check that we can handle the request */
+	assert((fileFlags & ((O_RDONLY|O_WRONLY|O_RDWR) | O_APPEND	|
+						 (O_RANDOM|O_SEQUENTIAL|O_TEMPORARY)	|
+						 _O_SHORT_LIVED							|
+						 (O_CREAT|O_TRUNC|O_EXCL) | (O_TEXT|O_BINARY))) == fileFlags);
+
+	sa.nLength=sizeof(sa);
+	sa.bInheritHandle=TRUE;
+	sa.lpSecurityDescriptor=NULL;
+
+	if ((h = CreateFile(fileName,
+						/* cannot use O_RDONLY, as it == 0 */
+						(fileFlags & O_RDWR)     ? (GENERIC_WRITE | GENERIC_READ) :
+						((fileFlags &  O_WRONLY) ?  GENERIC_WRITE : GENERIC_READ),
+						(FILE_SHARE_READ|FILE_SHARE_WRITE|FILE_SHARE_DELETE),
+						&sa,
+						openFlagsToCreateFileFlags(fileFlags),
+						FILE_ATTRIBUTE_NORMAL	|
+						((fileFlags &  O_RANDOM)		? FILE_FLAG_RANDOM_ACCESS	: 0) |
+						((fileFlags &  O_SEQUENTIAL)	? FILE_FLAG_SEQUENTIAL_SCAN	: 0) |
+						((fileFlags & _O_SHORT_LIVED)	? FILE_ATTRIBUTE_TEMPORARY	: 0) |
+						((fileFlags &  O_TEMPORARY)		? FILE_FLAG_DELETE_ON_CLOSE	: 0),
+						NULL)) == INVALID_HANDLE_VALUE)
+	{
+		switch (GetLastError())
+		{
+			/* EMFILE, ENFILE should not occur from CreateFile. */
+			case ERROR_PATH_NOT_FOUND:
+			case ERROR_FILE_NOT_FOUND:	errno = ENOENT; break;
+			case ERROR_FILE_EXISTS:		errno = EEXIST; break;
+			case ERROR_ACCESS_DENIED:	errno = EACCES; break;
+			default:
+				errno = EINVAL;
+		}
+		return -1;
+	}
+
+	/* _open_osfhandle will, on error, set errno accordingly */
+	if ((fd = _open_osfhandle((long)h,fileFlags&O_APPEND)) < 0 ||
+		(fileFlags&(O_TEXT|O_BINARY) && (_setmode(fd,fileFlags&(O_TEXT|O_BINARY)) < 0)))
+		CloseHandle(h); /* will not affect errno */
+	return fd;
+}
+
+#endif