--- Corinna Vinschen <[EMAIL PROTECTED]> wrote:
> On Jun 16 21:47, Pierre A. Humblet wrote:
> > On Wed, Jun 16, 2004 at 06:10:03PM -0700, Rick Rankin wrote:
> > > It seems to be the O_TRUNC flag that's causing the problem. If I remove
> it, the
> > > open succeeds when the file doesn't exist.
> > >
> > > Here's the output of 'strace opentest /cygdrive/m/foo | fgrep
> NtCreateFile'
> > > when /cygdrive/m/foo exists and with the O_TRUNC flag (1 line):
> > >
> > > 1081 154650 [main] opentest 1796 fhandler_base::open: 0 = NtCreateFile
> > > (0x32C, 40100080, m:\foo, io, NULL, 80, 7, 0, 20, NULL, 0)
> >
> > The most likely explanation is that one of your network drives does not
> fully
> > support the FILE_SUPERSEDE creation flag. Perhaps one could use
> FILE_OVERWRITE_IF
> > instead. The difference is slight and according to
> > http://www.osronline.com/article.cfm?id=302
> > this is how CREATE_ALWAYS is implemented. CREATE_ALWAYS was used up to
> > 1.5.9 on NT systems.
>
> That's what the Windows DDK docs have to say about this:
>
> "The CreateDisposition value FILE_SUPERSEDE requires that the caller have
> DELETE access to a existing file object. If so, a successful call to
> ZwCreateFile with FILE_SUPERSEDE on an existing file effectively deletes
> that file, and then recreates it. [...] Note that this type of disposition
> is consistent with the POSIX style of overwriting files.
> [...]
> Overwriting a file is semantically equivalent to a supersede operation,
> except for the following:
>
> The caller must have write access to the file, rather than delete access.
> [...]"
>
> Except for Pierre's guess of the file system not supporting FILE_SUPERSEDE,
> there's perhaps the other possible explanation, that you don't have the
> DELETE permission given in the directories security descriptor.
>
> I've applied a patch which substitutes FILE_SUPERSEDE with FILE_OVERWRITE_IF
> in Cygwin. It shows up in the next developers snapshot. Please give it
> a try.
Corinna,
Thanks for making the change so quickly! The 0617 snapshot definitely fixed the
tar problem. I don't know if it makes a difference for the internal change you
make, but I am able to delete files on that share, both with Cygwin and native
Windows commands, so the CREATE_ALWAYS flag should have worked as well.
I should mention that I've noticed what appears to be a completely unrelated
side effect in this snapshot. The initial symptom I noticed was that my bash
prompt no longer had the proper colors. I have some code in my .bashrc file to
add color to my prompt:
export SO="$(tput sgr0)$(tput setaf 7)$(tput setab 4)"
export SE="$(tput sgr0)"
export PS1='[EMAIL PROTECTED]:\W]${SE}\n$ '
After installing the snapshot, the color disappeared from my prompt, but
reappeared when I went back to the stock 1.5.10-3 DLL. After fooling around
with it a bit, I noticed that the problem seems to involve pipes in general,
but not in all circumstances. For example, with the snapshot,
echo $(cygpath -w -t mixed /)
echos nothing, but
echo $(uname)
seems to work. Both work properly in 1.5.10-3. The command 'tput clear' does
nothing with the 0617 snapshot but works with 1.5.10-3. I also have some
ActiveState perl scripts that run some Cygwin commands in a pipe and read the
output. The scripts I've tried so far are failing with the 0617 snapshot.
FYI, I just tried the 0616 snapshot and it has all the same symptoms.
Hopefully, you can reproduce this one. If you can't, let me know what I can do
to help.
Rick
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