msvcrt: sharing violation caused by duplicated hande in _get_osfhandle

[qingdoa daoo]

Hi,
 wine's implementation of _get_osfhandle is found to cause sharing violation in some apps. The author commented this piece of code with a block of FIXME
 warning about possible leakage. It turns out it's no just a matter of leakage.

A simple test program
 ------------------------------------------------------------
 #include "windows.h"
 #include "io.h"
 #include "fcntl.h"
 #include "share.h"
 int main()
 {
     int fd, bWritten;
     fd = _sopen("foo", _O_CREAT|_O_RDWR,_SH_DENYRW, 0);
     WriteFile((HANDLE)_get_osfhandle(fd), "bar", 3, &bWritten, NULL);
     _close(fd);
     fd = _open("foo", _O_RDONLY, 0);
     _write(1, fd==-1? "F\n" : "S\n", 2);
 }
 ------------------------------------------------------------
 The second _open fails with builtin msvcrt, not with native one.

The comment  says that the duplication is to make an inheritable hande.
 With the recent change in msvcrt's io init procedure, that shouldn't be a problem
 anymore.

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msvcrt: sharing violation caused by duplicated hande in _get_osfhandle

[Eric Pouech]

qingdoa daoo wrote:
> Hi,
> wine's implementation of _get_osfhandle is found to cause sharing 
> violation in some apps. The author commented this piece of code with a 
> block of FIXME
> warning about possible leakage. It turns out it's no just a matter of 
> leakage.
> A simple test program
>
> #include "windows.h"
> #include "io.h"
> #include "fcntl.h"
> #include "share.h"
> int main()
> {
>     int fd, bWritten;
>     fd = _sopen("foo", _O_CREAT|_O_RDWR,_SH_DENYRW, 0);
>     WriteFile((HANDLE)_get_osfhandle(fd), "bar", 3, &bWritten, NULL);
>     _close(fd);
>     fd = _open("foo", _O_RDONLY, 0);
>     _write(1, fd==-1? "F\n" : "S\n", 2);
> }
>
> The second _open fails with builtin msvcrt, not with native one.
>
> The comment  says that the duplication is to make an inheritable hande.
> With the recent change in msvcrt's io init procedure, that shouldn't be 
> a problem
> anymore.
>
> Blab-away for as little as 1¢/min. Make PC-to-Phone Calls 
> http://us.rd.yahoo.com/mail_us/taglines/postman2/*http://us.rd.yahoo.com/evt=39663/*http://voice.yahoo.com 
> using Yahoo! Messenger with Voice.

you're right... we should simply return the handle in get_osfhandle 
without duplicating the handle
could you submit the patch (the code snipnet would also be appreciated 
in the regression test suite)

A+