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76 lines
2.4 KiB
C
76 lines
2.4 KiB
C
/* Locate TLS data for a thread.
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Copyright (C) 2003-2013 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include "thread_dbP.h"
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td_err_e
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td_thr_tlsbase (const td_thrhandle_t *th,
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unsigned long int modid,
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psaddr_t *base)
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{
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td_err_e err;
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psaddr_t dtv, dtvslot, dtvptr;
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if (modid < 1)
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return TD_NOTLS;
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psaddr_t pd = th->th_unique;
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if (pd == 0)
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{
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/* This is the fake handle for the main thread before libpthread
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initialization. We are using 0 for its th_unique because we can't
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trust that its thread register has been initialized. But we need
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a real pointer to have any TLS access work. In case of dlopen'd
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libpthread, initialization might not be for quite some time. So
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try looking up the thread register now. Worst case, it's nonzero
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uninitialized garbage and we get bogus results for TLS access
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attempted too early. Tough. */
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td_thrhandle_t main_th;
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err = __td_ta_lookup_th_unique (th->th_ta_p, ps_getpid (th->th_ta_p->ph),
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&main_th);
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if (err == 0)
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pd = main_th.th_unique;
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if (pd == 0)
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return TD_TLSDEFER;
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}
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/* Get the DTV pointer from the thread descriptor. */
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err = DB_GET_FIELD (dtv, th->th_ta_p, pd, pthread, dtvp, 0);
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if (err != TD_OK)
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return err;
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/* Find the corresponding entry in the DTV. */
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err = DB_GET_FIELD_ADDRESS (dtvslot, th->th_ta_p, dtv, dtv, dtv, modid);
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if (err != TD_OK)
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return err;
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/* Extract the TLS block address from that DTV slot. */
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err = DB_GET_FIELD (dtvptr, th->th_ta_p, dtvslot, dtv_t, pointer_val, 0);
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if (err != TD_OK)
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return err;
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/* It could be that the memory for this module is not allocated for
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the given thread. */
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if ((uintptr_t) dtvptr & 1)
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return TD_TLSDEFER;
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*base = dtvptr;
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return TD_OK;
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}
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