nptl_db/td_ta_event_getmsg.c

   1 /* Retrieve event.
   2    Copyright (C) 1999-2019 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@redhat.com>, 1999.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <https://www.gnu.org/licenses/>.  */
  19
  20 #include <stddef.h>
  21 #include <string.h>
  22
  23 #include "thread_dbP.h"
  24
  25
  26 td_err_e
  27 td_ta_event_getmsg (const td_thragent_t *ta_arg, td_event_msg_t *msg)
  28 {
  29   td_thragent_t *const ta = (td_thragent_t *) ta_arg;
  30   td_err_e err;
  31   psaddr_t eventbuf, eventnum, eventdata;
  32   psaddr_t thp, next;
  33   void *copy;
  34
  35   /* XXX I cannot think of another way but using a static variable.  */
  36   /* XXX Use at least __thread once it is possible.  */
  37   static td_thrhandle_t th;
  38
  39   LOG ("td_thr_event_getmsg");
  40
  41   /* Test whether the TA parameter is ok.  */
  42   if (! ta_ok (ta))
  43     return TD_BADTA;
  44
  45   /* Get the pointer to the thread descriptor with the last event.  */
  46   err = DB_GET_VALUE (thp, ta, __nptl_last_event, 0);
  47   if (err != TD_OK)
  48     return err;
  49
  50   if (thp == 0)
  51     /* Nothing waiting.  */
  52     return TD_NOMSG;
  53
  54   /* Copy the event message buffer in from the inferior.  */
  55   err = DB_GET_FIELD_ADDRESS (eventbuf, ta, thp, pthread, eventbuf, 0);
  56   if (err == TD_OK)
  57     err = DB_GET_STRUCT (copy, ta, eventbuf, td_eventbuf_t);
  58   if (err != TD_OK)
  59     return err;
  60
  61   /* Read the event details from the target thread.  */
  62   err = DB_GET_FIELD_LOCAL (eventnum, ta, copy, td_eventbuf_t, eventnum, 0);
  63   if (err != TD_OK)
  64     return err;
  65   /* If the structure is on the list there better be an event recorded.  */
  66   if ((int) (uintptr_t) eventnum == TD_EVENT_NONE)
  67     return TD_DBERR;
  68
  69   /* Fill the user's data structure.  */
  70   err = DB_GET_FIELD_LOCAL (eventdata, ta, copy, td_eventbuf_t, eventdata, 0);
  71   if (err != TD_OK)
  72     return err;
  73
  74   /* Generate the thread descriptor.  */
  75   th.th_ta_p = (td_thragent_t *) ta;
  76   th.th_unique = thp;
  77
  78   /* Fill the user's data structure.  */
  79   msg->msg.data = (uintptr_t) eventdata;
  80   msg->event = (uintptr_t) eventnum;
  81   msg->th_p = &th;
  82
  83   /* And clear the event message in the target.  */
  84   memset (copy, 0, ta->ta_sizeof_td_eventbuf_t);
  85   err = DB_PUT_STRUCT (ta, eventbuf, td_eventbuf_t, copy);
  86   if (err != TD_OK)
  87     return err;
  88
  89   /* Get the pointer to the next descriptor with an event.  */
  90   err = DB_GET_FIELD (next, ta, thp, pthread, nextevent, 0);
  91   if (err != TD_OK)
  92     return err;
  93
  94   /* Store the pointer in the list head variable.  */
  95   err = DB_PUT_VALUE (ta, __nptl_last_event, 0, next);
  96   if (err != TD_OK)
  97     return err;
  98
  99   if (next != 0)
 100     /* Clear the next pointer in the current descriptor.  */
 101     err = DB_PUT_FIELD (ta, thp, pthread, nextevent, 0, 0);
 102
 103   return err;
 104 }