cpukit/libdl/rtl-debugger.c

0001 /* SPDX-License-Identifier: BSD-2-Clause */
0002
0003 /**
0004  * @file
0005  *
0006  * @ingroup rtl
0007  *
0008  * @brief RTEMS Module Loading Debugger Interface.
0009  *
0010  * Inspection of run-time linkers in NetBSD and Android show a common type of
0011  * structure that is used to interface to GDB. The NetBSD definition of this
0012  * interface is being used and is defined in <link.h>. It defines a protocol
0013  * that is used by GDB to inspect the state of dynamic libraries. I have not
0014  * checked GDB code at when writing this comment but I suspect GDB sets a break
0015  * point on the r_brk field of _rtld_debug and it has code that detects this
0016  * break point being hit. When this happens it reads the state and performs the
0017  * operation based on the r_state field.
0018  */
0019
0020 /*
0021  *  COPYRIGHT (c) 2012, 2018 Chris Johns <chrisj@rtems.org>
0022  *
0023  * Redistribution and use in source and binary forms, with or without
0024  * modification, are permitted provided that the following conditions
0025  * are met:
0026  * 1. Redistributions of source code must retain the above copyright
0027  *    notice, this list of conditions and the following disclaimer.
0028  * 2. Redistributions in binary form must reproduce the above copyright
0029  *    notice, this list of conditions and the following disclaimer in the
0030  *    documentation and/or other materials provided with the distribution.
0031  *
0032  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
0033  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
0034  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
0035  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
0036  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
0037  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
0038  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0039  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0040  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
0041  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
0042  * POSSIBILITY OF SUCH DAMAGE.
0043  */
0044
0045 #ifdef HAVE_CONFIG_H
0046 #include "config.h"
0047 #endif
0048
0049 #include <stdio.h>
0050 #include <link.h>
0051 #include <rtems/rtl/rtl.h>
0052 #include <rtems/rtl/rtl-trace.h>
0053 #include <rtems/rtl/rtl-obj-fwd.h>
0054
0055 struct r_debug  _rtld_debug;
0056
0057 void
0058 _rtld_debug_state (void)
0059 {
0060   /*
0061    * Empty. GDB only needs to hit this location.
0062    */
0063 }
0064
0065 int
0066 _rtld_linkmap_add (rtems_rtl_obj* obj)
0067 {
0068   struct link_map* l = obj->linkmap;
0069   struct link_map* prev;
0070   uint32_t         obj_num = obj->obj_num;
0071   int              i;
0072
0073   if (rtems_rtl_trace (RTEMS_RTL_TRACE_DETAIL))
0074     printf ("rtl: linkmap_add\n");
0075
0076   for (i = 0; i < obj_num; ++i)
0077   {
0078     l[i].sec_addr[rap_text] = obj->text_base;
0079     l[i].sec_addr[rap_const] = obj->const_base;
0080     l[i].sec_addr[rap_data] = obj->data_base;
0081     l[i].sec_addr[rap_bss] = obj->bss_base;
0082   }
0083
0084   if (_rtld_debug.r_map == NULL)
0085   {
0086     _rtld_debug.r_map = l;
0087   }
0088   else
0089   {
0090     for (prev = _rtld_debug.r_map; prev->l_next != NULL; prev = prev->l_next);
0091     l->l_prev = prev;
0092     prev->l_next = l;
0093   }
0094
0095   return true;
0096 }
0097
0098 void
0099 _rtld_linkmap_delete (rtems_rtl_obj* obj)
0100 {
0101   struct link_map* l = obj->linkmap;
0102
0103   /*
0104    *  link_maps are allocated together if not 1
0105    */
0106   struct link_map* e = l + obj->obj_num - 1;
0107
0108   if (l->l_prev == NULL)
0109   {
0110     if ((_rtld_debug.r_map = e->l_next) != NULL)
0111      _rtld_debug.r_map->l_prev = NULL;
0112   }
0113   else
0114   {
0115     if ((l->l_prev->l_next = e->l_next) != NULL)
0116       e->l_next->l_prev = l->l_prev;
0117   }
0118 }