Date: Mon, 04 Aug 2008 15:39:37 -0400 From: "Dixit, Amol" <dixit@netapp.com> To: freebsd-threads@freebsd.org Subject: Re: libpthread and gdbserver Message-ID: <48975AF9.3060204@netapp.com> In-Reply-To: <488A213F.70105@netapp.com> References: <488A213F.70105@netapp.com>
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Hi, I am now linking my sample application with libthr instead of libpthread, as libthr is the default going forward and it got me past issues in my previous mail (below). I had a question regarding FreeBsd libthread_db. In libthr_db_ops vector (libthr_db.c), we have pt_ta_map_id2thr() and pt_ta_map_lwp2thr(). The former maps tid to thread_handle and latter maps pid to tid. But pt_ta_map_lwp2thr() internally calls pt_ta_map_id2thr() in libthr_db.c so 'pid to tid' conversion is missing. If FreeBsd intends to keep it this way, I will have to modify gdbserver to not use 'pid' to find threads as Linux does. Can someone shed some light on this? Am I mailing the correct mailing-list with these queries? Thanks, Amol Dixit, Amol wrote: > Hi, > I am attempting to port gdbserver to freebsd (initially only for x86 & > libpthread) and I need some assistance with libpthread and libthread-db. > (i) From the code looks like libpthread does not provide any 'thread > creation event' symbol/address to be looked up by thread-db. I got > around this by adding a dummy function call before _thread_create > returned, and that new symbol can be used by thread-db to set > thread-creation breakpoint (analogous to _thread_bp_create in libthr). > (ii) Next hurdle is the race between thread-db and libpthread. > Thread-db tries to access '_thread_list' which is maintained in > libpthread and will eventually contain the 'initial thread' but this > list is NULL when thread-db tries to access it early. There is a > comment before _pthread_create() "It'd be nice to automatically have > _libpthread_init called on program execution..." which will be helpful > for thread-db. Currently I am stuck here as thread-db cannot enable > threading early enough since libpthread is assigning 'initial thread' > to '_thread_list' lazily. > > Am I on the right track on above issues? Any work going on in this area? > Really appreciate any help on this project. > > Thanks, > Amol > > > _______________________________________________ > freebsd-threads@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-threads > To unsubscribe, send any mail to > "freebsd-threads-unsubscribe@freebsd.org"
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