nptl_db/td_ta_map_lwp2thr.c

   1 /* Which thread is running on an LWP?
   2    Copyright (C) 2003, 2004, 2007 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include "thread_dbP.h"
  21 #include <stdlib.h>
  22 #include <byteswap.h>
  23 #include <sys/procfs.h>
  24
  25
  26 td_err_e
  27 __td_ta_lookup_th_unique (const td_thragent_t *ta_arg,
  28                           lwpid_t lwpid, td_thrhandle_t *th)
  29 {
  30   td_thragent_t *const ta = (td_thragent_t *) ta_arg;
  31   ps_err_e err;
  32   td_err_e terr;
  33   prgregset_t regs;
  34   psaddr_t addr;
  35
  36   LOG ("td_ta_map_lwp2thr");
  37
  38   /* Test whether the TA parameter is ok.  */
  39   if (! ta_ok (ta))
  40     return TD_BADTA;
  41
  42   if (ta->ta_howto == ta_howto_unknown)
  43     {
  44       /* We need to read in from the inferior the instructions what to do.  */
  45       psaddr_t howto;
  46
  47       err = td_lookup (ta->ph, SYM_TH_UNIQUE_CONST_THREAD_AREA, &howto);
  48       if (err == PS_OK)
  49         {
  50           err = ps_pdread (ta->ph, howto,
  51                            &ta->ta_howto_data.const_thread_area,
  52                            sizeof ta->ta_howto_data.const_thread_area);
  53           if (err != PS_OK)
  54             return TD_ERR;
  55           ta->ta_howto = ta_howto_const_thread_area;
  56           if (ta->ta_howto_data.const_thread_area & 0xff000000U)
  57             ta->ta_howto_data.const_thread_area
  58               = bswap_32 (ta->ta_howto_data.const_thread_area);
  59         }
  60       else
  61         {
  62           switch (sizeof (regs[0]))
  63             {
  64             case 8:
  65               err = td_lookup (ta->ph, SYM_TH_UNIQUE_REGISTER64, &howto);
  66               if (err == PS_OK)
  67                 ta->ta_howto = ta_howto_reg;
  68               else if (err == PS_NOSYM)
  69                 {
  70                   err = td_lookup (ta->ph,
  71                                    SYM_TH_UNIQUE_REGISTER64_THREAD_AREA,
  72                                    &howto);
  73                   if (err == PS_OK)
  74                     ta->ta_howto = ta_howto_reg_thread_area;
  75                 }
  76               break;
  77
  78             case 4:
  79               err = td_lookup (ta->ph, SYM_TH_UNIQUE_REGISTER32, &howto);
  80               if (err == PS_OK)
  81                 ta->ta_howto = ta_howto_reg;
  82               else if (err == PS_NOSYM)
  83                 {
  84                   err = td_lookup (ta->ph,
  85                                    SYM_TH_UNIQUE_REGISTER32_THREAD_AREA,
  86                                    &howto);
  87                   if (err == PS_OK)
  88                     ta->ta_howto = ta_howto_reg_thread_area;
  89                 }
  90               break;
  91
  92             default:
  93               abort ();
  94               return TD_DBERR;
  95             }
  96
  97           if (err != PS_OK)
  98             return TD_DBERR;
  99
 100           /* For either of these methods we read in the same descriptor.  */
 101           err = ps_pdread (ta->ph, howto,
 102                            ta->ta_howto_data.reg, DB_SIZEOF_DESC);
 103           if (err != PS_OK)
 104             return TD_ERR;
 105           if (DB_DESC_SIZE (ta->ta_howto_data.reg) == 0)
 106             return TD_DBERR;
 107           if (DB_DESC_SIZE (ta->ta_howto_data.reg) & 0xff000000U)
 108             {
 109               /* Byte-swap these words, though we leave the size word
 110                  in native order as the handy way to distinguish.  */
 111               DB_DESC_OFFSET (ta->ta_howto_data.reg)
 112                 = bswap_32 (DB_DESC_OFFSET (ta->ta_howto_data.reg));
 113               DB_DESC_NELEM (ta->ta_howto_data.reg)
 114                 = bswap_32 (DB_DESC_NELEM (ta->ta_howto_data.reg));
 115             }
 116         }
 117     }
 118
 119   switch (ta->ta_howto)
 120     {
 121     default:
 122       return TD_DBERR;
 123
 124     case ta_howto_reg:
 125       /* On most machines, we are just looking at a register.  */
 126       if (ps_lgetregs (ta->ph, lwpid, regs) != PS_OK)
 127         return TD_ERR;
 128       terr = _td_fetch_value_local (ta, ta->ta_howto_data.reg, -1,
 129                                     0, regs, &addr);
 130       if (terr != TD_OK)
 131         return terr;
 132
 133       /* In this descriptor the nelem word is overloaded as the bias.  */
 134       addr += (int32_t) DB_DESC_NELEM (ta->ta_howto_data.reg);
 135       th->th_unique = addr;
 136       break;
 137
 138     case ta_howto_const_thread_area:
 139       /* Some hosts don't have this call and this case won't be used.  */
 140 # pragma weak ps_get_thread_area
 141       if (&ps_get_thread_area == NULL)
 142         return TD_NOCAPAB;
 143
 144       /* A la x86-64, there is a magic index for get_thread_area.  */
 145       if (ps_get_thread_area (ta->ph, lwpid,
 146                               ta->ta_howto_data.const_thread_area,
 147                               &th->th_unique) != PS_OK)
 148         return TD_ERR;  /* XXX Other error value?  */
 149       break;
 150
 151     case ta_howto_reg_thread_area:
 152       if (&ps_get_thread_area == NULL)
 153         return TD_NOCAPAB;
 154
 155       /* A la i386, a register holds the index for get_thread_area.  */
 156       if (ps_lgetregs (ta->ph, lwpid, regs) != PS_OK)
 157         return TD_ERR;
 158       terr = _td_fetch_value_local (ta, ta->ta_howto_data.reg_thread_area,
 159                                     -1, 0, regs, &addr);
 160       if (terr != TD_OK)
 161         return terr;
 162       /* In this descriptor the nelem word is overloaded as scale factor.  */
 163       if (ps_get_thread_area
 164           (ta->ph, lwpid,
 165            ((addr - (psaddr_t) 0)
 166             >> DB_DESC_NELEM (ta->ta_howto_data.reg_thread_area)),
 167            &th->th_unique) != PS_OK)
 168         return TD_ERR;  /* XXX Other error value?  */
 169       break;
 170     }
 171
 172   /* Found it.  Now complete the `td_thrhandle_t' object.  */
 173   th->th_ta_p = ta;
 174
 175   return TD_OK;
 176 }
 177
 178 td_err_e
 179 td_ta_map_lwp2thr (const td_thragent_t *ta_arg,
 180                    lwpid_t lwpid, td_thrhandle_t *th)
 181 {
 182   td_thragent_t *const ta = (td_thragent_t *) ta_arg;
 183
 184   /* We cannot rely on thread registers and such information at all
 185      before __pthread_initialize_minimal has gotten far enough.  They
 186      sometimes contain garbage that would confuse us, left by the kernel
 187      at exec.  So if it looks like initialization is incomplete, we only
 188      fake a special descriptor for the initial thread.  */
 189
 190   psaddr_t list;
 191   td_err_e err = DB_GET_SYMBOL (list, ta, __stack_user);
 192   if (err != TD_OK)
 193     return err;
 194
 195   err = DB_GET_FIELD (list, ta, list, list_t, next, 0);
 196   if (err != TD_OK)
 197     return err;
 198
 199   if (list == 0)
 200     {
 201       if (ps_getpid (ta->ph) != lwpid)
 202         return TD_ERR;
 203       th->th_ta_p = ta;
 204       th->th_unique = 0;
 205       return TD_OK;
 206     }
 207
 208   return __td_ta_lookup_th_unique (ta_arg, lwpid, th);
 209 }