nptl_db/td_ta_thr_iter.c

   1 /* Iterate over a process's threads.
   2    Copyright (C) 1999,2000,2001,2002,2003,2004,2007,2008
   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, pid_t match_pid)
  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       /* Verify that this thread's pid field matches the child PID.
  82          If its pid field is negative, it's about to do a fork or it
  83          is the sole thread in a fork child.  */
  84       psaddr_t pid;
  85       err = DB_GET_FIELD_LOCAL (pid, ta, copy, pthread, pid, 0);
  86       if (err == TD_OK && (pid_t) (uintptr_t) pid < 0)
  87         {
  88           if (-(pid_t) (uintptr_t) pid == match_pid)
  89             /* It is about to do a fork, but is really still the parent PID.  */
  90             pid = (psaddr_t) (uintptr_t) match_pid;
  91           else
  92             /* It must be a fork child, whose new PID is in the tid field.  */
  93             err = DB_GET_FIELD_LOCAL (pid, ta, copy, pthread, tid, 0);
  94         }
  95       if (err != TD_OK)
  96         break;
  97
  98       if ((pid_t) (uintptr_t) pid == match_pid)
  99         {
 100           err = DB_GET_FIELD_LOCAL (schedpolicy, ta, copy, pthread,
 101                                     schedpolicy, 0);
 102           if (err != TD_OK)
 103             break;
 104           err = DB_GET_FIELD_LOCAL (schedprio, ta, copy, pthread,
 105                                     schedparam_sched_priority, 0);
 106           if (err != TD_OK)
 107             break;
 108
 109           /* Now test whether this thread matches the specified conditions.  */
 110
 111           /* Only if the priority level is as high or higher.  */
 112           int descr_pri = ((uintptr_t) schedpolicy == SCHED_OTHER
 113                            ? 0 : (uintptr_t) schedprio);
 114           if (descr_pri >= ti_pri)
 115             {
 116               /* Yep, it matches.  Call the callback function.  */
 117               td_thrhandle_t th;
 118               th.th_ta_p = (td_thragent_t *) ta;
 119               th.th_unique = addr;
 120               if (callback (&th, cbdata_p) != 0)
 121                 return TD_DBERR;
 122             }
 123         }
 124
 125       /* Get the pointer to the next element.  */
 126       err = DB_GET_FIELD_LOCAL (next, ta, copy + (ofs - (psaddr_t) 0), list_t,
 127                                 next, 0);
 128       if (err != TD_OK)
 129         break;
 130     }
 131
 132   return err;
 133 }
 134
 135
 136 td_err_e
 137 td_ta_thr_iter (const td_thragent_t *ta_arg, td_thr_iter_f *callback,
 138                 void *cbdata_p, td_thr_state_e state, int ti_pri,
 139                 sigset_t *ti_sigmask_p, unsigned int ti_user_flags)
 140 {
 141   td_thragent_t *const ta = (td_thragent_t *) ta_arg;
 142   td_err_e err;
 143   psaddr_t list = 0;
 144
 145   LOG ("td_ta_thr_iter");
 146
 147   /* Test whether the TA parameter is ok.  */
 148   if (! ta_ok (ta))
 149     return TD_BADTA;
 150
 151   /* The thread library keeps two lists for the running threads.  One
 152      list contains the thread which are using user-provided stacks
 153      (this includes the main thread) and the other includes the
 154      threads for which the thread library allocated the stacks.  We
 155      have to iterate over both lists separately.  We start with the
 156      list of threads with user-defined stacks.  */
 157
 158   pid_t pid = ps_getpid (ta->ph);
 159   err = DB_GET_SYMBOL (list, ta, __stack_user);
 160   if (err == TD_OK)
 161     err = iterate_thread_list (ta, callback, cbdata_p, state, ti_pri,
 162                                list, true, pid);
 163
 164   /* And the threads with stacks allocated by the implementation.  */
 165   if (err == TD_OK)
 166     err = DB_GET_SYMBOL (list, ta, stack_used);
 167   if (err == TD_OK)
 168     err = iterate_thread_list (ta, callback, cbdata_p, state, ti_pri,
 169                                list, false, pid);
 170
 171   return err;
 172 }