Current Samba master incorrectly returns STATUS_INVALID_HANDLE on copy_chunk

Jeremy Allison jra at samba.org
Wed Oct 9 20:18:53 UTC 2024


On Wed, Oct 09, 2024 at 10:00:01PM +0200, Ralph Boehme via samba-technical wrote:
>
>Hm, interesting find
>
>But I guess this won't help as with POSIX you can open() a file with 
>O_APPEND but then still call pread/pwrite on the resulting fd.

Is that true ?

The open(2) man page only says:

        O_APPEND
               The file is opened in append mode.  Before each write(2), the file offset is positioned at the end of
               the file, as if with lseek(2).  The modification of the file offset and the write operation are  per‐
               formed as a single atomic step.

Aha ! It's not true (at least on Linux :-).

The pwrite(2) man page says:

BUGS
        POSIX requires that opening a file with the O_APPEND flag should have no effect on  the  location  at  which
        pwrite()  writes  data.   However, on Linux, if a file is opened with O_APPEND, pwrite() appends data to the
        end of the file, regardless of the value of offset.

So FILE_APPEND_DATA|SYNCHRONIZE == O_APPEND, on Linux at least.




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