nptl_db/td_ta_event_getmsg.c

   1 /* Retrieve event.
   2    Copyright (C) 1999-2023 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, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <stddef.h>
  20 #include <string.h>
  21
  22 #include "thread_dbP.h"
  23
  24
  25 td_err_e
  26 td_ta_event_getmsg (const td_thragent_t *ta_arg, td_event_msg_t *msg)
  27 {
  28   td_thragent_t *const ta = (td_thragent_t *) ta_arg;
  29   td_err_e err;
  30   psaddr_t eventbuf, eventnum, eventdata;
  31   psaddr_t thp, next;
  32   void *copy;
  33
  34   /* XXX I cannot think of another way but using a static variable.  */
  35   /* XXX Use at least __thread once it is possible.  */
  36   static td_thrhandle_t th;
  37
  38   LOG ("td_thr_event_getmsg");
  39
  40   /* Test whether the TA parameter is ok.  */
  41   if (! ta_ok (ta))
  42     return TD_BADTA;
  43
  44   /* Get the pointer to the thread descriptor with the last event.  */
  45   err = DB_GET_VALUE (thp, ta, __nptl_last_event, 0);
  46   if (err != TD_OK)
  47     return err;
  48
  49   if (thp == 0)
  50     /* Nothing waiting.  */
  51     return TD_NOMSG;
  52
  53   /* Copy the event message buffer in from the inferior.  */
  54   err = DB_GET_FIELD_ADDRESS (eventbuf, ta, thp, pthread, eventbuf, 0);
  55   if (err == TD_OK)
  56     err = DB_GET_STRUCT (copy, ta, eventbuf, td_eventbuf_t);
  57   if (err != TD_OK)
  58     return err;
  59
  60   /* Read the event details from the target thread.  */
  61   err = DB_GET_FIELD_LOCAL (eventnum, ta, copy, td_eventbuf_t, eventnum, 0);
  62   if (err != TD_OK)
  63     return err;
  64   /* If the structure is on the list there better be an event recorded.  */
  65   if ((int) (uintptr_t) eventnum == TD_EVENT_NONE)
  66     return TD_DBERR;
  67
  68   /* Fill the user's data structure.  */
  69   err = DB_GET_FIELD_LOCAL (eventdata, ta, copy, td_eventbuf_t, eventdata, 0);
  70   if (err != TD_OK)
  71     return err;
  72
  73   /* Generate the thread descriptor.  */
  74   th.th_ta_p = (td_thragent_t *) ta;
  75   th.th_unique = thp;
  76
  77   /* Fill the user's data structure.  */
  78   msg->msg.data = (uintptr_t) eventdata;
  79   msg->event = (uintptr_t) eventnum;
  80   msg->th_p = &th;
  81
  82   /* And clear the event message in the target.  */
  83   memset (copy, 0, ta->ta_sizeof_td_eventbuf_t);
  84   err = DB_PUT_STRUCT (ta, eventbuf, td_eventbuf_t, copy);
  85   if (err != TD_OK)
  86     return err;
  87
  88   /* Get the pointer to the next descriptor with an event.  */
  89   err = DB_GET_FIELD (next, ta, thp, pthread, nextevent, 0);
  90   if (err != TD_OK)
  91     return err;
  92
  93   /* Store the pointer in the list head variable.  */
  94   err = DB_PUT_VALUE (ta, __nptl_last_event, 0, next);
  95   if (err != TD_OK)
  96     return err;
  97
  98   if (next != 0)
  99     /* Clear the next pointer in the current descriptor.  */
 100     err = DB_PUT_FIELD (ta, thp, pthread, nextevent, 0, 0);
 101
 102   return err;
 103 }