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Re: empty PATH, LD_LOAD_PATH default


Reini Urban schrieb:
I have a minor compatibility problem.

In Linux and other unices it is valid to start a process with an empty path because the LD_LOAD_PATH is correctly set to resolve the path for dynamic libraries.
I have this situation in perl TAINT-checked environments.
Our dll loader cannot handle LD_LOAD_PATH because in the case of linked shared libs we don't have our own loader, besides doing the dynamic dlopen.


So in linux et al. it is valid to do:
$ PATH= ./someprog-with-dependent-so
because linux has LD_LOAD_PATH and paths from /etc/ld.so.conf
while under cygwin it will fail.

Is there some fast way in the environment handling of the startup from cygwin processes before CreateProcess with a cygwin binary to detect an empty PATH, to mimic the behaviour of
LD_LOAD_PATH=/usr/bin:$SYSTEMROOT/System32
Setting PATH to "/usr/bin/:$SYSTEMROOT:$SYSTEMROOT/System32"
to resolve the dll's to please the kernel loader.

$SYSTEMROOT:$SYSTEMROOT/System32 is not needed, since native windows loads an exe with dll dependencies in $SYSTEMROOT/System32 and empty PATH correctly. Some CreateProcess magic.
So only some similar /usr/bin magic is required.


Or is this a stupid idea? It would make process slower I assume if we want to detect the dependency of shared libs in processes to be created.

I do not know how the situation of an empty PATH in cygwin
should be handled.
cygcheck does write "WARNING: PATH is not set at all!"
Currently the process fails to start, which seems logic, but is a bit incompatible.

-- Reini Urban http://phpwiki.org/ http://murbreak.at/ http://helsinki.at/ http://spacemovie.mur.at/

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