Re: Cannot exec() program outside of /bin if PATH is unset

[Corinna Vinschen <corinna-cygwin at cygwin dot com>]

On Oct 17 19:56, Christian Franke wrote:
> Corinna Vinschen wrote:
> >On Oct 17 11:10, Corinna Vinschen wrote:
> >>On Oct 16 23:51, Christian Franke wrote:
> >>>Corinna Vinschen wrote:
> >>>>...
> >>>>I implemented this in the latest snapshot.  It calls SetDllDirectory
> >>>>on Cygwin's /bin, and dlopen addiotnally tries to load the DLL with
> >>>>LoadLibraryEx(LOAD_WITH_ALTERED_SEARCH_PATH) if all else failed.
> >>>For some reason, the SetDllDirectory() call has no effect for exec():
> >>>
> >>>Testcase:
> >>>
> >>>$ unset PATH
> >>>
> >>>$ uname -srvm
> >>>-bash: uname: No such file or directory
> >>>
> >>>$ /bin/uname -srvm
> >>>CYGWIN_NT-6.1-WOW64 1.7.33s(0.277/5/3) 20141014 19:44:03 i686
> >>>
> >>>$ /usr/sbin/alternatives
> >>>/usr/sbin/alternatives: error while loading shared libraries: ?: cannot open
> >>>shared object file: No such file or directory
> >>Weird.  The same sequence of commands works fine for me on W8,
> >>W8.1 and W10 64 bit, under i686 as well as x86_64 Cygwin.
> >>
> >>[...]
> >>
> >>but it doesn't on Vista and W7, wow.
> >>
> >>The question now is, is it because the path given to SetDllDirectory
> >>is not propagated to child processes on older systems, or is it
> >>because the directory is only used in calls to LoadLibrary{Ex} on
> >>older systems.
> >>
> >>Stay tuned, I have to investigate this.
> >Ok, so prior to W8, the SetDllDirectory path is not propagated to child
> >processes :-|
> >
> >I created a patch and a new snapshot on https://cygwin.com/snapshots/
> >which calls SetDllDirectory during initialization of every process.
> >Please give it a try.
> 
> Now works.
> 
> cygwin_patches_for_postfix_count++; postfix_patches_for_cygwin_count--; :-)

You seem to like the idea... ;)


Thanks for testing,
Corinna

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

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