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Re: BUG: Bad call to GetFileSze in ext2fsprogs lib/ext2fs/getsize.c
- From: Earl Chew <earl_chew at agilent dot com>
- To: cygwin at cygwin dot com
- Date: Tue, 14 Sep 2004 10:32:47 -0700
- Subject: Re: BUG: Bad call to GetFileSze in ext2fsprogs lib/ext2fs/getsize.c
- References: <414532D7.8050506@agilent.com>
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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