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Message-ID: <41472B3F.8030800@agilent.com>
Date: Tue, 14 Sep 2004 10:32:47 -0700
From: Earl Chew <earl_chew AT agilent DOT com>
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To: cygwin AT cygwin DOT com
Subject: Re: BUG: Bad call to GetFileSze in ext2fsprogs lib/ext2fs/getsize.c
References: <414532D7 DOT 8050506 AT agilent DOT com>
In-Reply-To: <414532D7.8050506@agilent.com>
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Earl Chew wrote:
> The call to GetFileSize() doesn't match the Microsoft documentation,
> and invariably mis-sizes the disk image as zero.

A couple of comments regarding your recent changes:

a. GetFileSize() returns the bits 32-63 of the file size in
    the 2nd parameter. I think code like this is more better:

	DWORD high_filesize;
	filesize = GetFileSize(dev, &high_filesize);
	if (filesize != INVALID_FILE_SIZE || GetLastError() != NO_ERROR)
		*retblocks (((unsigned long long) high_filesize << 32)
                             + filesize) / blocksize;

b. Use of CreateFile() causes problems because win32 doesn't know
    about the cygwin mount points. Code like this is more flexible:

	fd = open(file, O_RDONLY | O_BINARY);
	if (fd == -1)
	    return EBADF;
	dev = (HANDLE) get_osfhandle(fd);

	...
	close(fd);

c. Similarly, code in unix_io.c needs to force binary mode to
    avoid getting incorrect results when cygwin decides the image
    is text!

	open_flags = (flags & IO_FLAG_RW) ? O_RDWR : O_RDONLY;
	#ifdef O_BINARY
	open_flags |= O_BINARY;
	#endif

Earl

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