Date: Thu, 19 Sep 2002 06:27:45 -0700 (PDT) From: Christophe Vedel <cv@validy.com> To: freebsd-gnats-submit@FreeBSD.org Subject: misc/42956: dlclose gives "invalid shared object handle" when called through the fini function of another module Message-ID: <200209191327.g8JDRjlX072147@www.freebsd.org>
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>Number: 42956
>Category: misc
>Synopsis: dlclose gives "invalid shared object handle" when called through the fini function of another module
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Thu Sep 19 06:30:03 PDT 2002
>Closed-Date:
>Last-Modified:
>Originator: Christophe Vedel
>Release: 4.6-RELEASE
>Organization:
Validy
>Environment:
FreeBSD freebsd46.home.org 4.6-RELEASE FreeBSD 4.6-RELEASE #0: Tue Jun 11 06:14:12 GMT 2002 murray@builder.freebsdmall.com:/usr/src/sys/compile/GENERIC i386
>Description:
Dlopened ELF module A dlopens ELF module B and keeps a handle to it in a static C++ object. When the process exits, rtld_exit is called and the fini function for A is called. This function calls the object static destructor and it tries to dlclose the handle to B. This gives a "invalid shared object handle" message because the refcount field for the handle is zero.
All refcount fields have been set to zero in rtld_exit so that objlist_call_fini calls all fini functions.
>How-To-Repeat:
dlclose a valid shared object handle from the fini function of another dynamically loaded shared object
>Fix:
possible fix: in libebxec/rtld-elf/rtld.c, add a "force" parameter to objlist_call_fini to be able to force the calls to fini even when refcount is not zero. In rtld_exit, do not zero the refcount fields, instead set the force parameter to one when calling objlist_call_fini. In dlclose, set the force parameter to zero.
>Release-Note:
>Audit-Trail:
>Unformatted:
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