problem with errno in readdir64_r() and readdir_r()

[Filippo ARCIDIACONO]

> -----Original Message-----
> From: uclibc-bounces at uclibc.org 
> [mailto:uclibc-bounces at uclibc.org] On Behalf Of Kovesdi Gyorgy
> Sent: Wednesday, March 25, 2009 9:49 AM
> To: uclibc at uclibc.org
> Subject: problem with errno in readdir64_r() and readdir_r()
> 
> Hi,
> 
> I found that the above mentioned functions can return with 
> strange error values in some cases: it is possible to return 
> the previous value of the 'errno' without modifying it.
> e.g. the 'svn' executable reports strange errors due to this bug.
If there is a bug you should provide a simlpe test case that raise the
problem.
> 
> Those functions contain this code:
> 
> bytes = __getdents64(dir->dd_fd, dir->dd_buf, dir->dd_max); 
> if (bytes <= 0) {
>     *result = NULL;
>     ret = (bytes==0)? 0 : errno;
>     goto all_done;
> ...
> 
> AFAIK the functions __getdents64() and __getdents() return 
> zero at the end of the directory, and the 'errno' is not 
> modified in this case (because it is not an error), so the 
> previous value of 'errno' can be returned by these functions.
> I suggest a modification:
> 
> bytes = __getdents64(dir->dd_fd, dir->dd_buf, dir->dd_max); 
> if (bytes == 0) {
>     *result = NULL;
>     ret = 0;
>     goto all_done;
> } else if (bytes < 0) {
>     *result = NULL;
>     ret = (bytes==0)? 0 : errno;
>     goto all_done;
> ...
Sorry, but I cannot see any distinction with the previous one.
> 
> or something similar. I did not test it, because it is too 
> complicated for me to recompile the whole uClibc. It is just an idea.
> 
> Regards
> K. Gy.
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