/* Locate TLS data for a thread.
- Copyright (C) 2003, 2006 Free Software Foundation, Inc.
+ Copyright (C) 2003-2016 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
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, write to the Free
- Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
- 02111-1307 USA. */
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
#include "thread_dbP.h"
+#include <link.h>
+/* Get the DTV slotinfo list head entry from the dynamic loader state
+ into *LISTHEAD. */
+static td_err_e
+dtv_slotinfo_list (td_thragent_t *ta,
+ psaddr_t *listhead)
+{
+ td_err_e err;
+ psaddr_t head;
+
+ if (ta->ta_addr__rtld_global == 0
+ && td_mod_lookup (ta->ph, LD_SO, SYM__rtld_global,
+ &ta->ta_addr__rtld_global) != PS_OK)
+ ta->ta_addr__rtld_global = (void*)-1;
+
+ if (ta->ta_addr__rtld_global != (void*)-1)
+ {
+ err = DB_GET_FIELD (head, ta, ta->ta_addr__rtld_global,
+ rtld_global, _dl_tls_dtv_slotinfo_list, 0);
+ if (err != TD_OK)
+ return err;
+ }
+ else
+ {
+ if (ta->ta_addr__dl_tls_dtv_slotinfo_list == 0
+ && td_mod_lookup (ta->ph, NULL, SYM__dl_tls_dtv_slotinfo_list,
+ &ta->ta_addr__dl_tls_dtv_slotinfo_list) != PS_OK)
+ return TD_ERR;
+
+ err = _td_fetch_value (ta, ta->ta_var__dl_tls_dtv_slotinfo_list,
+ SYM_DESC__dl_tls_dtv_slotinfo_list,
+ 0, ta->ta_addr__dl_tls_dtv_slotinfo_list, &head);
+ if (err != TD_OK)
+ return err;
+ }
+
+ *listhead = head;
+ return TD_OK;
+}
+
+/* Get the address of the DTV slotinfo entry for MODID into
+ *DTVSLOTINFO. */
+static td_err_e
+dtv_slotinfo (td_thragent_t *ta,
+ unsigned long int modid,
+ psaddr_t *dtvslotinfo)
+{
+ td_err_e err;
+ psaddr_t slot, temp;
+ size_t slbase = 0;
+
+ err = dtv_slotinfo_list (ta, &slot);
+ if (err != TD_OK)
+ return err;
+
+ while (slot)
+ {
+ /* Get the number of entries in this list entry's array. */
+ err = DB_GET_FIELD (temp, ta, slot, dtv_slotinfo_list, len, 0);
+ if (err != TD_OK)
+ return err;
+ size_t len = (uintptr_t)temp;
+
+ /* Did we find the list entry for modid? */
+ if (modid < slbase + len)
+ break;
+
+ /* We didn't, so get the next list entry. */
+ slbase += len;
+ err = DB_GET_FIELD (temp, ta, slot, dtv_slotinfo_list,
+ next, 0);
+ if (err != TD_OK)
+ return err;
+ slot = temp;
+ }
+
+ /* We reached the end of the list and found nothing. */
+ if (!slot)
+ return TD_ERR;
+
+ /* Take the slotinfo for modid from the list entry. */
+ err = DB_GET_FIELD_ADDRESS (temp, ta, slot, dtv_slotinfo_list,
+ slotinfo, modid - slbase);
+ if (err != TD_OK)
+ return err;
+ slot = temp;
+
+ *dtvslotinfo = slot;
+ return TD_OK;
+}
+
+/* Return in *BASE the base address of the TLS block for MODID within
+ TH.
+
+ It should return success and yield the correct pointer in any
+ circumstance where the TLS block for the module and thread
+ requested has already been initialized.
+
+ It should fail with TD_TLSDEFER only when the thread could not
+ possibly have observed any values in that TLS block. That way, the
+ debugger can fall back to showing initial values from the PT_TLS
+ segment (and refusing attempts to mutate) for the TD_TLSDEFER case,
+ and never fail to make the values the program will actually see
+ available to the user of the debugger. */
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;
+ psaddr_t dtv, dtvslot, dtvptr, temp;
if (modid < 1)
return TD_NOTLS;
+ psaddr_t 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;
+ }
+
+ err = dtv_slotinfo (th->th_ta_p, modid, &temp);
+ if (err != TD_OK)
+ return err;
+
+ psaddr_t slot;
+ err = DB_GET_STRUCT (slot, th->th_ta_p, temp, dtv_slotinfo);
+ if (err != TD_OK)
+ return err;
+
+ /* Take the link_map from the slotinfo. */
+ psaddr_t map;
+ err = DB_GET_FIELD_LOCAL (map, th->th_ta_p, slot, dtv_slotinfo, map, 0);
+ if (err != TD_OK)
+ return err;
+ if (!map)
+ return TD_ERR;
+
+ /* Ok, the modid is good, now find out what DTV generation it
+ requires. */
+ err = DB_GET_FIELD_LOCAL (temp, th->th_ta_p, slot, dtv_slotinfo, gen, 0);
+ if (err != TD_OK)
+ return err;
+ size_t modgen = (uintptr_t)temp;
+
/* Get the DTV pointer from the thread descriptor. */
- err = DB_GET_FIELD (dtv, th->th_ta_p, th->th_unique, pthread, dtvp, 0);
+ err = DB_GET_FIELD (dtv, th->th_ta_p, pd, pthread, dtvp, 0);
+ if (err != TD_OK)
+ return err;
+
+ psaddr_t dtvgenloc;
+ /* Get the DTV generation count at dtv[0].counter. */
+ err = DB_GET_FIELD_ADDRESS (dtvgenloc, th->th_ta_p, dtv, dtv, dtv, 0);
+ if (err != TD_OK)
+ return err;
+ err = DB_GET_FIELD (temp, th->th_ta_p, dtvgenloc, dtv_t, counter, 0);
if (err != TD_OK)
return err;
+ size_t dtvgen = (uintptr_t)temp;
+
+ /* Is the DTV current enough? */
+ if (dtvgen < modgen)
+ {
+ try_static_tls:
+ /* If the module uses Static TLS, we're still good. */
+ err = DB_GET_FIELD (temp, th->th_ta_p, map, link_map, l_tls_offset, 0);
+ if (err != TD_OK)
+ return err;
+ ptrdiff_t tlsoff = (uintptr_t)temp;
+
+ if (tlsoff != FORCED_DYNAMIC_TLS_OFFSET
+ && tlsoff != NO_TLS_OFFSET)
+ {
+ psaddr_t tp = pd;
+
+#if TLS_TCB_AT_TP
+ dtvptr = tp - tlsoff;
+#elif TLS_DTV_AT_TP
+ dtvptr = tp + tlsoff + TLS_PRE_TCB_SIZE;
+#else
+# error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
+#endif
+
+ *base = dtvptr;
+ return TD_OK;
+ }
+
+ return TD_TLSDEFER;
+ }
/* Find the corresponding entry in the DTV. */
err = DB_GET_FIELD_ADDRESS (dtvslot, th->th_ta_p, dtv, dtv, dtv, modid);
/* It could be that the memory for this module is not allocated for
the given thread. */
if ((uintptr_t) dtvptr & 1)
- return TD_TLSDEFER;
+ goto try_static_tls;
*base = dtvptr;
return TD_OK;
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