[PATCH v3] Cygwin: respect PC_SYM_FOLLOW and PC_SYM_NOFOLLOW_REP with inner links
Jeremy Drake
cygwin@jdrake.com
Tue Jul 6 17:38:02 GMT 2021
On Tue, 6 Jul 2021, Corinna Vinschen wrote:
> This formatting is just ugly. I suggest to move the PC_SYM_* test
> to the block after the 32 bit code and reuse the existing braces,
> just with adapted indentation, i. e.:
+1. I was trying to avoid reformatting otherwise unchanged lines to
reduce patch size.
> > @@ -3704,7 +3708,8 @@ chdir (const char *in_dir)
> >
> > /* Convert path. PC_NONULLEMPTY ensures that we don't check for
> > NULL/empty/invalid again. */
> > - path_conv path (in_dir, PC_SYM_FOLLOW | PC_POSIX | PC_NONULLEMPTY);
> > + path_conv path (in_dir, PC_SYM_FOLLOW | PC_POSIX | PC_NONULLEMPTY
> > + | PC_SYM_NOFOLLOW_REP);
> > if (path.error)
> > {
> > set_errno (path.error);
>
> I'm still not convinced that we should do this. I'm pretty certain this
> will result in problems in Cygwin processes when you least expect them.
>
> Consider that the output of getcwd and realpath/readlink on the same
> path may differ after this patch. Using PC_SYM_NOFOLLOW_REP like this
> also changes the normal sym follow handling for the last path component
> in path_copnv::check, potentially.
>
> This looks like here be dragons. A good solution would change the
> used native tools to allow paths > MAX_PATH finally, or to use other,
> equivalent tools already allowing that.
I am not convinced that this even completely solved the issues I was
seeing, or some of the reports of issues with unc paths suddenly showing
up instead of mapped drives in native tools that weren't expecting them.
But, I do think respecting the PC_SYM_NOFOLLOW_REP flag for inner links is
correct, and I am sending a new version.
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