1: /* Communicate dynamic linker state to the debugger at runtime.
    2:    Copyright (C) 1996, 1998,2000,2002,2004,2005,2006
    3:         Free Software Foundation, Inc.
    4:    This file is part of the GNU C Library.
    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, write to the Free
   18:    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   19:    02111-1307 USA.  */
   20: 
   21: #include <ldsodefs.h>
   22: 
   23: 
   24: /* These are the members in the public `struct link_map' type.
   25:    Sanity check that the internal type and the public type match.  */
   26: #define VERIFY_MEMBER(name) \
   27:   (offsetof (struct link_map_public, name) == offsetof (struct link_map, name))
   28: extern const int verify_link_map_members[(VERIFY_MEMBER (l_addr)
   29:                                           && VERIFY_MEMBER (l_name)
   30:                                           && VERIFY_MEMBER (l_ld)
   31:                                           && VERIFY_MEMBER (l_next)
   32:                                           && VERIFY_MEMBER (l_prev))
   33:                                          ? 1 : -1];
   34: 
   35: /* This structure communicates dl state to the debugger.  The debugger
   36:    normally finds it via the DT_DEBUG entry in the dynamic section, but in
   37:    a statically-linked program there is no dynamic section for the debugger
   38:    to examine and it looks for this particular symbol name.  */
   39: struct r_debug _r_debug;
   40: 
   41: 
   42: /* Initialize _r_debug if it has not already been done.  The argument is
   43:    the run-time load address of the dynamic linker, to be put in
   44:    _r_debug.r_ldbase.  Returns the address of _r_debug.  */
   45: 
   46: struct r_debug *
   47: internal_function
   48: _dl_debug_initialize (ElfW(Addr) ldbase, Lmid_t ns)
   49: {
   50:   struct r_debug *r;
   51: 
   52:   if (ns == LM_ID_BASE)
   53:     r = &_r_debug;
   54:   else
   55:     r = &GL(dl_ns)[ns]._ns_debug;
   56: 
   57:   if (r->r_map == NULL || ldbase != 0)
   58:     {
   59:       /* Tell the debugger where to find the map of loaded objects.  */
   60:       r->r_version = 1  /* R_DEBUG_VERSION XXX */;
   61:       r->r_ldbase = ldbase ?: _r_debug.r_ldbase;
   62:       r->r_map = (void *) GL(dl_ns)[ns]._ns_loaded;
   63:       r->r_brk = (ElfW(Addr)) &_dl_debug_state;
   64:     }
   65: 
   66:   return r;
   67: }
   68: 
   69: 
   70: /* This function exists solely to have a breakpoint set on it by the
   71:    debugger.  The debugger is supposed to find this function's address by
   72:    examining the r_brk member of struct r_debug, but GDB 4.15 in fact looks
   73:    for this particular symbol name in the PT_INTERP file.  */
   74: void
   75: _dl_debug_state (void)
   76: {
   77: }
   78: rtld_hidden_def (_dl_debug_state)