bdrewery at FreeBSD.org
Thu Feb 12 00:30:24 UTC 2015
On 12/26/2014 10:53 AM, Konstantin Belousov wrote:
> Proposed patch does the following:
It seems libthr.3 needs to be updated for the dlopen(3) support, to
remove some of r272070. Also note the ordering comment (which I know you
may not be ready to change yet).
> INTERACTION WITH RUN-TIME LINKER
> The libthr library must appear before libc in the global order of
> depended objects.
> Loading libthr with the dlopen(3) call in the process after the program
> binary is activated is not supported, and causes miscellaneous and hard-
> to-diagnose misbehaviour. This is due to libthr interposing several
> important libc symbols to provide thread-safe services. In particular,
> errno and the locking stubs from libc are affected. This requirement is
> currently not enforced.
> If the program loads any modules at run-time, and those modules may
> require threading services, the main program binary must be linked with
> libpthread, even if it does not require any services from the library.
> libthr cannot be unloaded; the dlclose(3) function does not perform any
> action when called with a handle for libthr. One of the reasons is that
> the interposing of libc functions cannot be undone.
As for the dlclose(3) refusing to work on libthr, I cannot find the
supporting code. Where is it?
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