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Re: sqlite defect


On Jul 19 12:03, Corinna Vinschen wrote:
> On Jul 19 10:56, jojelino wrote:
> > On 2013-07-18 PM 5:59, Corinna Vinschen wrote:> On Jul 18 17:11,
> > jojelino wrote:
> > >> On 2013-07-18 AM 10:53, Warren Young wrote:
> > >>> Nothing so simple.  Locking is handled at the OS and/or Cygwin DLL
> > >>> level.  The build change between 3.7.16.2 and 3.7.17-3 is that
> > we're now
> > >>> relying on new features in the Cygwin DLL to do Windows-style
> > locking by
> > >>> default.
> > >>>
> > >>> Older versions of Cygwin SQLite bypassed the Cygwin DLL entirely for
> > >>> this, going straight to the Win32 API, thereby preventing the DLL from
> > >>> interposing itself for the "posix" case.
> > >>>
> > >> Mandatory locking feature of cygwin used in sqlite is broken.
> > >
> > > Simple testcase in plain C?
> 
> Thanks, but...
> 
> > #include <stdio.h>
> > #include <fcntl.h>
> > #include <assert.h>
> > #include <string.h>
> > #include <sys/file.h>
> > int
> > main()
> > {
> >   int fd = open("asdf.txt", O_BINARY | O_RDWR | O_NOINHERIT | O_CREAT);
> >   const char* buf =
> > "KKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK\0";
> >   int i=0;
> >   write(fd, buf, strlen(buf));
> >   fcntl(fd,F_LCK_MANDATORY,0);
> >   assert(flock(fd,F_SETOWN)==0);
>                     ^^^^^^^^
>                     F_SETOWN is no valid flag for flock(2).

...and, btw., fcntl(fd, F_SETOWN) is only supported on sockets.


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat

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