nptl_db/td_ta_thr_iter.c

   1 /* Iterate over a process's threads.
   2    Copyright (C) 1999,2000,2001,2002,2003,2004,2007
   3         Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5    Contributed by Ulrich Drepper <drepper@redhat.com>, 1999.
   6
   7    The GNU C Library is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU Lesser General Public
   9    License as published by the Free Software Foundation; either
  10    version 2.1 of the License, or (at your option) any later version.
  11
  12    The GNU C Library is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15    Lesser General Public License for more details.
  16
  17    You should have received a copy of the GNU Lesser General Public
  18    License along with the GNU C Library; if not, write to the Free
  19    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  20    02111-1307 USA.  */
  21
  22 #include "thread_dbP.h"
  23
  24
  25 static td_err_e
  26 iterate_thread_list (td_thragent_t *ta, td_thr_iter_f *callback,
  27                      void *cbdata_p, td_thr_state_e state, int ti_pri,
  28                      psaddr_t head, bool fake_empty)
  29 {
  30   td_err_e err;
  31   psaddr_t next, ofs;
  32   void *copy;
  33
  34   /* Test the state.
  35      XXX This is incomplete.  Normally this test should be in the loop.  */
  36   if (state != TD_THR_ANY_STATE)
  37     return TD_OK;
  38
  39   err = DB_GET_FIELD (next, ta, head, list_t, next, 0);
  40   if (err != TD_OK)
  41     return err;
  42
  43   if (next == 0 && fake_empty)
  44     {
  45       /* __pthread_initialize_minimal has not run.  There is just the main
  46          thread to return.  We cannot rely on its thread register.  They
  47          sometimes contain garbage that would confuse us, left by the
  48          kernel at exec.  So if it looks like initialization is incomplete,
  49          we only fake a special descriptor for the initial thread.  */
  50       td_thrhandle_t th = { ta, 0 };
  51       return callback (&th, cbdata_p) != 0 ? TD_DBERR : TD_OK;
  52     }
  53
  54   /* Cache the offset from struct pthread to its list_t member.  */
  55   err = DB_GET_FIELD_ADDRESS (ofs, ta, 0, pthread, list, 0);
  56   if (err != TD_OK)
  57     return err;
  58
  59   if (ta->ta_sizeof_pthread == 0)
  60     {
  61       err = _td_check_sizeof (ta, &ta->ta_sizeof_pthread, SYM_SIZEOF_pthread);
  62       if (err != TD_OK)
  63         return err;
  64     }
  65   copy = __alloca (ta->ta_sizeof_pthread);
  66
  67   while (next != head)
  68     {
  69       psaddr_t addr, schedpolicy, schedprio;
  70
  71       addr = next - (ofs - (psaddr_t) 0);
  72       if (next == 0 || addr == 0) /* Sanity check.  */
  73         return TD_DBERR;
  74
  75       /* Copy the whole descriptor in once so we can access the several
  76          fields locally.  Excess copying in one go is much better than
  77          multiple ps_pdread calls.  */
  78       if (ps_pdread (ta->ph, addr, copy, ta->ta_sizeof_pthread) != PS_OK)
  79         return TD_ERR;
  80
  81       err = DB_GET_FIELD_LOCAL (schedpolicy, ta, copy, pthread,
  82                                 schedpolicy, 0);
  83       if (err != TD_OK)
  84         break;
  85       err = DB_GET_FIELD_LOCAL (schedprio, ta, copy, pthread,
  86                                 schedparam_sched_priority, 0);
  87       if (err != TD_OK)
  88         break;
  89
  90       /* Now test whether this thread matches the specified conditions.  */
  91
  92       /* Only if the priority level is as high or higher.  */
  93       int descr_pri = ((uintptr_t) schedpolicy == SCHED_OTHER
  94                        ? 0 : (uintptr_t) schedprio);
  95       if (descr_pri >= ti_pri)
  96         {
  97           /* Yep, it matches.  Call the callback function.  */
  98           td_thrhandle_t th;
  99           th.th_ta_p = (td_thragent_t *) ta;
 100           th.th_unique = addr;
 101           if (callback (&th, cbdata_p) != 0)
 102             return TD_DBERR;
 103         }
 104
 105       /* Get the pointer to the next element.  */
 106       err = DB_GET_FIELD_LOCAL (next, ta, copy + (ofs - (psaddr_t) 0), list_t,
 107                                 next, 0);
 108       if (err != TD_OK)
 109         break;
 110     }
 111
 112   return err;
 113 }
 114
 115
 116 td_err_e
 117 td_ta_thr_iter (const td_thragent_t *ta_arg, td_thr_iter_f *callback,
 118                 void *cbdata_p, td_thr_state_e state, int ti_pri,
 119                 sigset_t *ti_sigmask_p, unsigned int ti_user_flags)
 120 {
 121   td_thragent_t *const ta = (td_thragent_t *) ta_arg;
 122   td_err_e err;
 123   psaddr_t list = 0;
 124
 125   LOG ("td_ta_thr_iter");
 126
 127   /* Test whether the TA parameter is ok.  */
 128   if (! ta_ok (ta))
 129     return TD_BADTA;
 130
 131   /* The thread library keeps two lists for the running threads.  One
 132      list contains the thread which are using user-provided stacks
 133      (this includes the main thread) and the other includes the
 134      threads for which the thread library allocated the stacks.  We
 135      have to iterate over both lists separately.  We start with the
 136      list of threads with user-defined stacks.  */
 137
 138   err = DB_GET_SYMBOL (list, ta, __stack_user);
 139   if (err == TD_OK)
 140     err = iterate_thread_list (ta, callback, cbdata_p, state, ti_pri,
 141                                list, true);
 142
 143   /* And the threads with stacks allocated by the implementation.  */
 144   if (err == TD_OK)
 145     err = DB_GET_SYMBOL (list, ta, stack_used);
 146   if (err == TD_OK)
 147     err = iterate_thread_list (ta, callback, cbdata_p, state, ti_pri,
 148                                list, false);
 149
 150   return err;
 151 }