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- /* Locate TLS data for a thread.
- Copyright (C) 2003, 2006, 2007 Free Software Foundation, Inc.
- This file is part of the GNU C Library.
- The GNU C Library is free software; you can redistribute it and/or
- modify it under the terms of the GNU Lesser General Public
- License as published by the Free Software Foundation; either
- version 2.1 of the License, or (at your option) any later version.
- The GNU C Library is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Lesser General Public License for more details.
- You should have received a copy of the GNU Lesser General Public
- License along with the GNU C Library; if not, see
- <http://www.gnu.org/licenses/>. */
- #include "thread_dbP.h"
- td_err_e
- td_thr_tlsbase (const td_thrhandle_t *th,
- unsigned long int modid,
- psaddr_t *base)
- {
- td_err_e err;
- psaddr_t dtv, dtvslot, dtvptr, pd;
- if (modid < 1)
- return TD_NOTLS;
- pd = th->th_unique;
- if (pd == 0)
- {
- /* This is the fake handle for the main thread before libpthread
- initialization. We are using 0 for its th_unique because we can't
- trust that its thread register has been initialized. But we need
- a real pointer to have any TLS access work. In case of dlopen'd
- libpthread, initialization might not be for quite some time. So
- try looking up the thread register now. Worst case, it's nonzero
- uninitialized garbage and we get bogus results for TLS access
- attempted too early. Tough. */
- td_thrhandle_t main_th;
- err = __td_ta_lookup_th_unique (th->th_ta_p, ps_getpid (th->th_ta_p->ph),
- &main_th);
- if (err == 0)
- pd = main_th.th_unique;
- if (pd == 0)
- return TD_TLSDEFER;
- }
- /* Get the DTV pointer from the thread descriptor. */
- err = DB_GET_FIELD (dtv, th->th_ta_p, pd, pthread, dtvp, 0);
- if (err != TD_OK)
- return err;
- /* Find the corresponding entry in the DTV. */
- err = DB_GET_FIELD_ADDRESS (dtvslot, th->th_ta_p, dtv, dtv, dtv, modid);
- if (err != TD_OK)
- return err;
- /* Extract the TLS block address from that DTV slot. */
- err = DB_GET_FIELD (dtvptr, th->th_ta_p, dtvslot, dtv_t, pointer_val, 0);
- if (err != TD_OK)
- return err;
- /* It could be that the memory for this module is not allocated for
- the given thread. */
- if ((uintptr_t) dtvptr & 1)
- return TD_TLSDEFER;
- *base = dtvptr;
- return TD_OK;
- }
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