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1181 |
sfurman |
/* Handle SunOS shared libraries for GDB, the GNU Debugger.
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Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000,
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2001
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Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include "defs.h"
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#include <sys/types.h>
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#include <signal.h>
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#include "gdb_string.h"
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#include <sys/param.h>
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#include <fcntl.h>
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/* SunOS shared libs need the nlist structure. */
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#include <a.out.h>
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#include <link.h>
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#include "symtab.h"
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#include "bfd.h"
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#include "symfile.h"
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#include "objfiles.h"
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#include "gdbcore.h"
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#include "inferior.h"
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#include "solist.h"
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/* Link map info to include in an allocated so_list entry */
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struct lm_info
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{
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/* Pointer to copy of link map from inferior. The type is char *
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rather than void *, so that we may use byte offsets to find the
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various fields without the need for a cast. */
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char *lm;
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};
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/* Symbols which are used to locate the base of the link map structures. */
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static char *debug_base_symbols[] =
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{
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"_DYNAMIC",
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"_DYNAMIC__MGC",
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NULL
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};
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static char *main_name_list[] =
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{
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"main_$main",
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NULL
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};
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/* Macro to extract an address from a solib structure.
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When GDB is configured for some 32-bit targets (e.g. Solaris 2.7
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sparc), BFD is configured to handle 64-bit targets, so CORE_ADDR is
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64 bits. We have to extract only the significant bits of addresses
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to get the right address when accessing the core file BFD. */
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#define SOLIB_EXTRACT_ADDRESS(MEMBER) \
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extract_address (&(MEMBER), sizeof (MEMBER))
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/* local data declarations */
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static struct link_dynamic dynamic_copy;
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static struct link_dynamic_2 ld_2_copy;
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static struct ld_debug debug_copy;
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static CORE_ADDR debug_addr;
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static CORE_ADDR flag_addr;
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#ifndef offsetof
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#define offsetof(TYPE, MEMBER) ((unsigned long) &((TYPE *)0)->MEMBER)
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#endif
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#define fieldsize(TYPE, MEMBER) (sizeof (((TYPE *)0)->MEMBER))
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/* link map access functions */
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static CORE_ADDR
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LM_ADDR (struct so_list *so)
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{
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int lm_addr_offset = offsetof (struct link_map, lm_addr);
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int lm_addr_size = fieldsize (struct link_map, lm_addr);
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return (CORE_ADDR) extract_signed_integer (so->lm_info->lm + lm_addr_offset,
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lm_addr_size);
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}
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static CORE_ADDR
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LM_NEXT (struct so_list *so)
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{
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int lm_next_offset = offsetof (struct link_map, lm_next);
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int lm_next_size = fieldsize (struct link_map, lm_next);
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return extract_address (so->lm_info->lm + lm_next_offset, lm_next_size);
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}
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static CORE_ADDR
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LM_NAME (struct so_list *so)
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{
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int lm_name_offset = offsetof (struct link_map, lm_name);
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int lm_name_size = fieldsize (struct link_map, lm_name);
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return extract_address (so->lm_info->lm + lm_name_offset, lm_name_size);
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}
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static CORE_ADDR debug_base; /* Base of dynamic linker structures */
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/* Local function prototypes */
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static int match_main (char *);
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/* Allocate the runtime common object file. */
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static void
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allocate_rt_common_objfile (void)
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{
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struct objfile *objfile;
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struct objfile *last_one;
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objfile = (struct objfile *) xmalloc (sizeof (struct objfile));
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memset (objfile, 0, sizeof (struct objfile));
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objfile->md = NULL;
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objfile->psymbol_cache = bcache_xmalloc ();
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objfile->macro_cache = bcache_xmalloc ();
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obstack_specify_allocation (&objfile->psymbol_obstack, 0, 0, xmalloc,
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xfree);
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obstack_specify_allocation (&objfile->symbol_obstack, 0, 0, xmalloc,
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xfree);
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obstack_specify_allocation (&objfile->type_obstack, 0, 0, xmalloc,
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xfree);
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objfile->name = mstrsave (objfile->md, "rt_common");
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/* Add this file onto the tail of the linked list of other such files. */
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objfile->next = NULL;
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if (object_files == NULL)
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object_files = objfile;
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else
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{
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for (last_one = object_files;
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last_one->next;
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last_one = last_one->next);
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last_one->next = objfile;
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}
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rt_common_objfile = objfile;
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}
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/* Read all dynamically loaded common symbol definitions from the inferior
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and put them into the minimal symbol table for the runtime common
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objfile. */
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static void
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solib_add_common_symbols (CORE_ADDR rtc_symp)
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{
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struct rtc_symb inferior_rtc_symb;
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struct nlist inferior_rtc_nlist;
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int len;
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char *name;
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/* Remove any runtime common symbols from previous runs. */
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if (rt_common_objfile != NULL && rt_common_objfile->minimal_symbol_count)
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{
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obstack_free (&rt_common_objfile->symbol_obstack, 0);
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obstack_specify_allocation (&rt_common_objfile->symbol_obstack, 0, 0,
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xmalloc, xfree);
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rt_common_objfile->minimal_symbol_count = 0;
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rt_common_objfile->msymbols = NULL;
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}
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init_minimal_symbol_collection ();
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make_cleanup_discard_minimal_symbols ();
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while (rtc_symp)
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{
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read_memory (rtc_symp,
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(char *) &inferior_rtc_symb,
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sizeof (inferior_rtc_symb));
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read_memory (SOLIB_EXTRACT_ADDRESS (inferior_rtc_symb.rtc_sp),
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(char *) &inferior_rtc_nlist,
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sizeof (inferior_rtc_nlist));
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if (inferior_rtc_nlist.n_type == N_COMM)
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{
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/* FIXME: The length of the symbol name is not available, but in the
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current implementation the common symbol is allocated immediately
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behind the name of the symbol. */
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len = inferior_rtc_nlist.n_value - inferior_rtc_nlist.n_un.n_strx;
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name = xmalloc (len);
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read_memory (SOLIB_EXTRACT_ADDRESS (inferior_rtc_nlist.n_un.n_name),
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name, len);
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/* Allocate the runtime common objfile if necessary. */
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if (rt_common_objfile == NULL)
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allocate_rt_common_objfile ();
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prim_record_minimal_symbol (name, inferior_rtc_nlist.n_value,
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mst_bss, rt_common_objfile);
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xfree (name);
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}
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rtc_symp = SOLIB_EXTRACT_ADDRESS (inferior_rtc_symb.rtc_next);
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}
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/* Install any minimal symbols that have been collected as the current
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minimal symbols for the runtime common objfile. */
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install_minimal_symbols (rt_common_objfile);
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}
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/*
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LOCAL FUNCTION
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locate_base -- locate the base address of dynamic linker structs
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SYNOPSIS
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CORE_ADDR locate_base (void)
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DESCRIPTION
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For both the SunOS and SVR4 shared library implementations, if the
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inferior executable has been linked dynamically, there is a single
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address somewhere in the inferior's data space which is the key to
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locating all of the dynamic linker's runtime structures. This
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address is the value of the debug base symbol. The job of this
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function is to find and return that address, or to return 0 if there
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is no such address (the executable is statically linked for example).
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For SunOS, the job is almost trivial, since the dynamic linker and
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all of it's structures are statically linked to the executable at
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link time. Thus the symbol for the address we are looking for has
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already been added to the minimal symbol table for the executable's
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objfile at the time the symbol file's symbols were read, and all we
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have to do is look it up there. Note that we explicitly do NOT want
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to find the copies in the shared library.
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The SVR4 version is a bit more complicated because the address
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is contained somewhere in the dynamic info section. We have to go
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to a lot more work to discover the address of the debug base symbol.
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Because of this complexity, we cache the value we find and return that
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value on subsequent invocations. Note there is no copy in the
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executable symbol tables.
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*/
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static CORE_ADDR
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locate_base (void)
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{
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struct minimal_symbol *msymbol;
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CORE_ADDR address = 0;
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char **symbolp;
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/* For SunOS, we want to limit the search for the debug base symbol to the
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executable being debugged, since there is a duplicate named symbol in the
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shared library. We don't want the shared library versions. */
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for (symbolp = debug_base_symbols; *symbolp != NULL; symbolp++)
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{
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msymbol = lookup_minimal_symbol (*symbolp, NULL, symfile_objfile);
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if ((msymbol != NULL) && (SYMBOL_VALUE_ADDRESS (msymbol) != 0))
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{
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address = SYMBOL_VALUE_ADDRESS (msymbol);
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return (address);
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}
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}
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return (0);
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}
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/*
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LOCAL FUNCTION
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290 |
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first_link_map_member -- locate first member in dynamic linker's map
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SYNOPSIS
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static CORE_ADDR first_link_map_member (void)
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DESCRIPTION
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298 |
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Find the first element in the inferior's dynamic link map, and
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return its address in the inferior. This function doesn't copy the
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link map entry itself into our address space; current_sos actually
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does the reading. */
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304 |
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static CORE_ADDR
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first_link_map_member (void)
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{
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307 |
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CORE_ADDR lm = 0;
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308 |
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read_memory (debug_base, (char *) &dynamic_copy, sizeof (dynamic_copy));
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310 |
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if (dynamic_copy.ld_version >= 2)
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{
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312 |
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/* It is a version that we can deal with, so read in the secondary
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structure and find the address of the link map list from it. */
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read_memory (SOLIB_EXTRACT_ADDRESS (dynamic_copy.ld_un.ld_2),
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(char *) &ld_2_copy, sizeof (struct link_dynamic_2));
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lm = SOLIB_EXTRACT_ADDRESS (ld_2_copy.ld_loaded);
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}
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return (lm);
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}
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static int
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open_symbol_file_object (void *from_ttyp)
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323 |
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{
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324 |
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return 1;
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325 |
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}
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326 |
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327 |
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/* LOCAL FUNCTION
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329 |
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330 |
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current_sos -- build a list of currently loaded shared objects
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331 |
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332 |
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SYNOPSIS
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333 |
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334 |
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struct so_list *current_sos ()
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335 |
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336 |
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DESCRIPTION
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337 |
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338 |
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Build a list of `struct so_list' objects describing the shared
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339 |
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objects currently loaded in the inferior. This list does not
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include an entry for the main executable file.
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341 |
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342 |
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Note that we only gather information directly available from the
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inferior --- we don't examine any of the shared library files
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themselves. The declaration of `struct so_list' says which fields
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we provide values for. */
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346 |
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347 |
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static struct so_list *
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348 |
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sunos_current_sos (void)
|
349 |
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{
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350 |
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CORE_ADDR lm;
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351 |
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struct so_list *head = 0;
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352 |
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struct so_list **link_ptr = &head;
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353 |
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int errcode;
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354 |
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char *buffer;
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355 |
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356 |
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/* Make sure we've looked up the inferior's dynamic linker's base
|
357 |
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structure. */
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358 |
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if (! debug_base)
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359 |
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{
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360 |
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debug_base = locate_base ();
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361 |
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362 |
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/* If we can't find the dynamic linker's base structure, this
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363 |
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must not be a dynamically linked executable. Hmm. */
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364 |
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if (! debug_base)
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365 |
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return 0;
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366 |
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}
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367 |
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368 |
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/* Walk the inferior's link map list, and build our list of
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369 |
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`struct so_list' nodes. */
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370 |
|
|
lm = first_link_map_member ();
|
371 |
|
|
while (lm)
|
372 |
|
|
{
|
373 |
|
|
struct so_list *new
|
374 |
|
|
= (struct so_list *) xmalloc (sizeof (struct so_list));
|
375 |
|
|
struct cleanup *old_chain = make_cleanup (xfree, new);
|
376 |
|
|
|
377 |
|
|
memset (new, 0, sizeof (*new));
|
378 |
|
|
|
379 |
|
|
new->lm_info = xmalloc (sizeof (struct lm_info));
|
380 |
|
|
make_cleanup (xfree, new->lm_info);
|
381 |
|
|
|
382 |
|
|
new->lm_info->lm = xmalloc (sizeof (struct link_map));
|
383 |
|
|
make_cleanup (xfree, new->lm_info->lm);
|
384 |
|
|
memset (new->lm_info->lm, 0, sizeof (struct link_map));
|
385 |
|
|
|
386 |
|
|
read_memory (lm, new->lm_info->lm, sizeof (struct link_map));
|
387 |
|
|
|
388 |
|
|
lm = LM_NEXT (new);
|
389 |
|
|
|
390 |
|
|
/* Extract this shared object's name. */
|
391 |
|
|
target_read_string (LM_NAME (new), &buffer,
|
392 |
|
|
SO_NAME_MAX_PATH_SIZE - 1, &errcode);
|
393 |
|
|
if (errcode != 0)
|
394 |
|
|
{
|
395 |
|
|
warning ("current_sos: Can't read pathname for load map: %s\n",
|
396 |
|
|
safe_strerror (errcode));
|
397 |
|
|
}
|
398 |
|
|
else
|
399 |
|
|
{
|
400 |
|
|
strncpy (new->so_name, buffer, SO_NAME_MAX_PATH_SIZE - 1);
|
401 |
|
|
new->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0';
|
402 |
|
|
xfree (buffer);
|
403 |
|
|
strcpy (new->so_original_name, new->so_name);
|
404 |
|
|
}
|
405 |
|
|
|
406 |
|
|
/* If this entry has no name, or its name matches the name
|
407 |
|
|
for the main executable, don't include it in the list. */
|
408 |
|
|
if (! new->so_name[0]
|
409 |
|
|
|| match_main (new->so_name))
|
410 |
|
|
free_so (new);
|
411 |
|
|
else
|
412 |
|
|
{
|
413 |
|
|
new->next = 0;
|
414 |
|
|
*link_ptr = new;
|
415 |
|
|
link_ptr = &new->next;
|
416 |
|
|
}
|
417 |
|
|
|
418 |
|
|
discard_cleanups (old_chain);
|
419 |
|
|
}
|
420 |
|
|
|
421 |
|
|
return head;
|
422 |
|
|
}
|
423 |
|
|
|
424 |
|
|
|
425 |
|
|
/* On some systems, the only way to recognize the link map entry for
|
426 |
|
|
the main executable file is by looking at its name. Return
|
427 |
|
|
non-zero iff SONAME matches one of the known main executable names. */
|
428 |
|
|
|
429 |
|
|
static int
|
430 |
|
|
match_main (char *soname)
|
431 |
|
|
{
|
432 |
|
|
char **mainp;
|
433 |
|
|
|
434 |
|
|
for (mainp = main_name_list; *mainp != NULL; mainp++)
|
435 |
|
|
{
|
436 |
|
|
if (strcmp (soname, *mainp) == 0)
|
437 |
|
|
return (1);
|
438 |
|
|
}
|
439 |
|
|
|
440 |
|
|
return (0);
|
441 |
|
|
}
|
442 |
|
|
|
443 |
|
|
|
444 |
|
|
static int
|
445 |
|
|
sunos_in_dynsym_resolve_code (CORE_ADDR pc)
|
446 |
|
|
{
|
447 |
|
|
return 0;
|
448 |
|
|
}
|
449 |
|
|
|
450 |
|
|
/*
|
451 |
|
|
|
452 |
|
|
LOCAL FUNCTION
|
453 |
|
|
|
454 |
|
|
disable_break -- remove the "mapping changed" breakpoint
|
455 |
|
|
|
456 |
|
|
SYNOPSIS
|
457 |
|
|
|
458 |
|
|
static int disable_break ()
|
459 |
|
|
|
460 |
|
|
DESCRIPTION
|
461 |
|
|
|
462 |
|
|
Removes the breakpoint that gets hit when the dynamic linker
|
463 |
|
|
completes a mapping change.
|
464 |
|
|
|
465 |
|
|
*/
|
466 |
|
|
|
467 |
|
|
static int
|
468 |
|
|
disable_break (void)
|
469 |
|
|
{
|
470 |
|
|
CORE_ADDR breakpoint_addr; /* Address where end bkpt is set */
|
471 |
|
|
|
472 |
|
|
int in_debugger = 0;
|
473 |
|
|
|
474 |
|
|
/* Read the debugger structure from the inferior to retrieve the
|
475 |
|
|
address of the breakpoint and the original contents of the
|
476 |
|
|
breakpoint address. Remove the breakpoint by writing the original
|
477 |
|
|
contents back. */
|
478 |
|
|
|
479 |
|
|
read_memory (debug_addr, (char *) &debug_copy, sizeof (debug_copy));
|
480 |
|
|
|
481 |
|
|
/* Set `in_debugger' to zero now. */
|
482 |
|
|
|
483 |
|
|
write_memory (flag_addr, (char *) &in_debugger, sizeof (in_debugger));
|
484 |
|
|
|
485 |
|
|
breakpoint_addr = SOLIB_EXTRACT_ADDRESS (debug_copy.ldd_bp_addr);
|
486 |
|
|
write_memory (breakpoint_addr, (char *) &debug_copy.ldd_bp_inst,
|
487 |
|
|
sizeof (debug_copy.ldd_bp_inst));
|
488 |
|
|
|
489 |
|
|
/* For the SVR4 version, we always know the breakpoint address. For the
|
490 |
|
|
SunOS version we don't know it until the above code is executed.
|
491 |
|
|
Grumble if we are stopped anywhere besides the breakpoint address. */
|
492 |
|
|
|
493 |
|
|
if (stop_pc != breakpoint_addr)
|
494 |
|
|
{
|
495 |
|
|
warning ("stopped at unknown breakpoint while handling shared libraries");
|
496 |
|
|
}
|
497 |
|
|
|
498 |
|
|
return 1;
|
499 |
|
|
}
|
500 |
|
|
|
501 |
|
|
|
502 |
|
|
/*
|
503 |
|
|
|
504 |
|
|
LOCAL FUNCTION
|
505 |
|
|
|
506 |
|
|
enable_break -- arrange for dynamic linker to hit breakpoint
|
507 |
|
|
|
508 |
|
|
SYNOPSIS
|
509 |
|
|
|
510 |
|
|
int enable_break (void)
|
511 |
|
|
|
512 |
|
|
DESCRIPTION
|
513 |
|
|
|
514 |
|
|
Both the SunOS and the SVR4 dynamic linkers have, as part of their
|
515 |
|
|
debugger interface, support for arranging for the inferior to hit
|
516 |
|
|
a breakpoint after mapping in the shared libraries. This function
|
517 |
|
|
enables that breakpoint.
|
518 |
|
|
|
519 |
|
|
For SunOS, there is a special flag location (in_debugger) which we
|
520 |
|
|
set to 1. When the dynamic linker sees this flag set, it will set
|
521 |
|
|
a breakpoint at a location known only to itself, after saving the
|
522 |
|
|
original contents of that place and the breakpoint address itself,
|
523 |
|
|
in it's own internal structures. When we resume the inferior, it
|
524 |
|
|
will eventually take a SIGTRAP when it runs into the breakpoint.
|
525 |
|
|
We handle this (in a different place) by restoring the contents of
|
526 |
|
|
the breakpointed location (which is only known after it stops),
|
527 |
|
|
chasing around to locate the shared libraries that have been
|
528 |
|
|
loaded, then resuming.
|
529 |
|
|
|
530 |
|
|
For SVR4, the debugger interface structure contains a member (r_brk)
|
531 |
|
|
which is statically initialized at the time the shared library is
|
532 |
|
|
built, to the offset of a function (_r_debug_state) which is guaran-
|
533 |
|
|
teed to be called once before mapping in a library, and again when
|
534 |
|
|
the mapping is complete. At the time we are examining this member,
|
535 |
|
|
it contains only the unrelocated offset of the function, so we have
|
536 |
|
|
to do our own relocation. Later, when the dynamic linker actually
|
537 |
|
|
runs, it relocates r_brk to be the actual address of _r_debug_state().
|
538 |
|
|
|
539 |
|
|
The debugger interface structure also contains an enumeration which
|
540 |
|
|
is set to either RT_ADD or RT_DELETE prior to changing the mapping,
|
541 |
|
|
depending upon whether or not the library is being mapped or unmapped,
|
542 |
|
|
and then set to RT_CONSISTENT after the library is mapped/unmapped.
|
543 |
|
|
*/
|
544 |
|
|
|
545 |
|
|
static int
|
546 |
|
|
enable_break (void)
|
547 |
|
|
{
|
548 |
|
|
int success = 0;
|
549 |
|
|
int j;
|
550 |
|
|
int in_debugger;
|
551 |
|
|
|
552 |
|
|
/* Get link_dynamic structure */
|
553 |
|
|
|
554 |
|
|
j = target_read_memory (debug_base, (char *) &dynamic_copy,
|
555 |
|
|
sizeof (dynamic_copy));
|
556 |
|
|
if (j)
|
557 |
|
|
{
|
558 |
|
|
/* unreadable */
|
559 |
|
|
return (0);
|
560 |
|
|
}
|
561 |
|
|
|
562 |
|
|
/* Calc address of debugger interface structure */
|
563 |
|
|
|
564 |
|
|
debug_addr = SOLIB_EXTRACT_ADDRESS (dynamic_copy.ldd);
|
565 |
|
|
|
566 |
|
|
/* Calc address of `in_debugger' member of debugger interface structure */
|
567 |
|
|
|
568 |
|
|
flag_addr = debug_addr + (CORE_ADDR) ((char *) &debug_copy.ldd_in_debugger -
|
569 |
|
|
(char *) &debug_copy);
|
570 |
|
|
|
571 |
|
|
/* Write a value of 1 to this member. */
|
572 |
|
|
|
573 |
|
|
in_debugger = 1;
|
574 |
|
|
write_memory (flag_addr, (char *) &in_debugger, sizeof (in_debugger));
|
575 |
|
|
success = 1;
|
576 |
|
|
|
577 |
|
|
return (success);
|
578 |
|
|
}
|
579 |
|
|
|
580 |
|
|
/*
|
581 |
|
|
|
582 |
|
|
LOCAL FUNCTION
|
583 |
|
|
|
584 |
|
|
special_symbol_handling -- additional shared library symbol handling
|
585 |
|
|
|
586 |
|
|
SYNOPSIS
|
587 |
|
|
|
588 |
|
|
void special_symbol_handling ()
|
589 |
|
|
|
590 |
|
|
DESCRIPTION
|
591 |
|
|
|
592 |
|
|
Once the symbols from a shared object have been loaded in the usual
|
593 |
|
|
way, we are called to do any system specific symbol handling that
|
594 |
|
|
is needed.
|
595 |
|
|
|
596 |
|
|
For SunOS4, this consists of grunging around in the dynamic
|
597 |
|
|
linkers structures to find symbol definitions for "common" symbols
|
598 |
|
|
and adding them to the minimal symbol table for the runtime common
|
599 |
|
|
objfile.
|
600 |
|
|
|
601 |
|
|
*/
|
602 |
|
|
|
603 |
|
|
static void
|
604 |
|
|
sunos_special_symbol_handling (void)
|
605 |
|
|
{
|
606 |
|
|
int j;
|
607 |
|
|
|
608 |
|
|
if (debug_addr == 0)
|
609 |
|
|
{
|
610 |
|
|
/* Get link_dynamic structure */
|
611 |
|
|
|
612 |
|
|
j = target_read_memory (debug_base, (char *) &dynamic_copy,
|
613 |
|
|
sizeof (dynamic_copy));
|
614 |
|
|
if (j)
|
615 |
|
|
{
|
616 |
|
|
/* unreadable */
|
617 |
|
|
return;
|
618 |
|
|
}
|
619 |
|
|
|
620 |
|
|
/* Calc address of debugger interface structure */
|
621 |
|
|
/* FIXME, this needs work for cross-debugging of core files
|
622 |
|
|
(byteorder, size, alignment, etc). */
|
623 |
|
|
|
624 |
|
|
debug_addr = SOLIB_EXTRACT_ADDRESS (dynamic_copy.ldd);
|
625 |
|
|
}
|
626 |
|
|
|
627 |
|
|
/* Read the debugger structure from the inferior, just to make sure
|
628 |
|
|
we have a current copy. */
|
629 |
|
|
|
630 |
|
|
j = target_read_memory (debug_addr, (char *) &debug_copy,
|
631 |
|
|
sizeof (debug_copy));
|
632 |
|
|
if (j)
|
633 |
|
|
return; /* unreadable */
|
634 |
|
|
|
635 |
|
|
/* Get common symbol definitions for the loaded object. */
|
636 |
|
|
|
637 |
|
|
if (debug_copy.ldd_cp)
|
638 |
|
|
{
|
639 |
|
|
solib_add_common_symbols (SOLIB_EXTRACT_ADDRESS (debug_copy.ldd_cp));
|
640 |
|
|
}
|
641 |
|
|
}
|
642 |
|
|
|
643 |
|
|
/* Relocate the main executable. This function should be called upon
|
644 |
|
|
stopping the inferior process at the entry point to the program.
|
645 |
|
|
The entry point from BFD is compared to the PC and if they are
|
646 |
|
|
different, the main executable is relocated by the proper amount.
|
647 |
|
|
|
648 |
|
|
As written it will only attempt to relocate executables which
|
649 |
|
|
lack interpreter sections. It seems likely that only dynamic
|
650 |
|
|
linker executables will get relocated, though it should work
|
651 |
|
|
properly for a position-independent static executable as well. */
|
652 |
|
|
|
653 |
|
|
static void
|
654 |
|
|
sunos_relocate_main_executable (void)
|
655 |
|
|
{
|
656 |
|
|
asection *interp_sect;
|
657 |
|
|
CORE_ADDR pc = read_pc ();
|
658 |
|
|
|
659 |
|
|
/* Decide if the objfile needs to be relocated. As indicated above,
|
660 |
|
|
we will only be here when execution is stopped at the beginning
|
661 |
|
|
of the program. Relocation is necessary if the address at which
|
662 |
|
|
we are presently stopped differs from the start address stored in
|
663 |
|
|
the executable AND there's no interpreter section. The condition
|
664 |
|
|
regarding the interpreter section is very important because if
|
665 |
|
|
there *is* an interpreter section, execution will begin there
|
666 |
|
|
instead. When there is an interpreter section, the start address
|
667 |
|
|
is (presumably) used by the interpreter at some point to start
|
668 |
|
|
execution of the program.
|
669 |
|
|
|
670 |
|
|
If there is an interpreter, it is normal for it to be set to an
|
671 |
|
|
arbitrary address at the outset. The job of finding it is
|
672 |
|
|
handled in enable_break().
|
673 |
|
|
|
674 |
|
|
So, to summarize, relocations are necessary when there is no
|
675 |
|
|
interpreter section and the start address obtained from the
|
676 |
|
|
executable is different from the address at which GDB is
|
677 |
|
|
currently stopped.
|
678 |
|
|
|
679 |
|
|
[ The astute reader will note that we also test to make sure that
|
680 |
|
|
the executable in question has the DYNAMIC flag set. It is my
|
681 |
|
|
opinion that this test is unnecessary (undesirable even). It
|
682 |
|
|
was added to avoid inadvertent relocation of an executable
|
683 |
|
|
whose e_type member in the ELF header is not ET_DYN. There may
|
684 |
|
|
be a time in the future when it is desirable to do relocations
|
685 |
|
|
on other types of files as well in which case this condition
|
686 |
|
|
should either be removed or modified to accomodate the new file
|
687 |
|
|
type. (E.g, an ET_EXEC executable which has been built to be
|
688 |
|
|
position-independent could safely be relocated by the OS if
|
689 |
|
|
desired. It is true that this violates the ABI, but the ABI
|
690 |
|
|
has been known to be bent from time to time.) - Kevin, Nov 2000. ]
|
691 |
|
|
*/
|
692 |
|
|
|
693 |
|
|
interp_sect = bfd_get_section_by_name (exec_bfd, ".interp");
|
694 |
|
|
if (interp_sect == NULL
|
695 |
|
|
&& (bfd_get_file_flags (exec_bfd) & DYNAMIC) != 0
|
696 |
|
|
&& bfd_get_start_address (exec_bfd) != pc)
|
697 |
|
|
{
|
698 |
|
|
struct cleanup *old_chain;
|
699 |
|
|
struct section_offsets *new_offsets;
|
700 |
|
|
int i, changed;
|
701 |
|
|
CORE_ADDR displacement;
|
702 |
|
|
|
703 |
|
|
/* It is necessary to relocate the objfile. The amount to
|
704 |
|
|
relocate by is simply the address at which we are stopped
|
705 |
|
|
minus the starting address from the executable.
|
706 |
|
|
|
707 |
|
|
We relocate all of the sections by the same amount. This
|
708 |
|
|
behavior is mandated by recent editions of the System V ABI.
|
709 |
|
|
According to the System V Application Binary Interface,
|
710 |
|
|
Edition 4.1, page 5-5:
|
711 |
|
|
|
712 |
|
|
... Though the system chooses virtual addresses for
|
713 |
|
|
individual processes, it maintains the segments' relative
|
714 |
|
|
positions. Because position-independent code uses relative
|
715 |
|
|
addressesing between segments, the difference between
|
716 |
|
|
virtual addresses in memory must match the difference
|
717 |
|
|
between virtual addresses in the file. The difference
|
718 |
|
|
between the virtual address of any segment in memory and
|
719 |
|
|
the corresponding virtual address in the file is thus a
|
720 |
|
|
single constant value for any one executable or shared
|
721 |
|
|
object in a given process. This difference is the base
|
722 |
|
|
address. One use of the base address is to relocate the
|
723 |
|
|
memory image of the program during dynamic linking.
|
724 |
|
|
|
725 |
|
|
The same language also appears in Edition 4.0 of the System V
|
726 |
|
|
ABI and is left unspecified in some of the earlier editions. */
|
727 |
|
|
|
728 |
|
|
displacement = pc - bfd_get_start_address (exec_bfd);
|
729 |
|
|
changed = 0;
|
730 |
|
|
|
731 |
|
|
new_offsets = xcalloc (symfile_objfile->num_sections,
|
732 |
|
|
sizeof (struct section_offsets));
|
733 |
|
|
old_chain = make_cleanup (xfree, new_offsets);
|
734 |
|
|
|
735 |
|
|
for (i = 0; i < symfile_objfile->num_sections; i++)
|
736 |
|
|
{
|
737 |
|
|
if (displacement != ANOFFSET (symfile_objfile->section_offsets, i))
|
738 |
|
|
changed = 1;
|
739 |
|
|
new_offsets->offsets[i] = displacement;
|
740 |
|
|
}
|
741 |
|
|
|
742 |
|
|
if (changed)
|
743 |
|
|
objfile_relocate (symfile_objfile, new_offsets);
|
744 |
|
|
|
745 |
|
|
do_cleanups (old_chain);
|
746 |
|
|
}
|
747 |
|
|
}
|
748 |
|
|
|
749 |
|
|
/*
|
750 |
|
|
|
751 |
|
|
GLOBAL FUNCTION
|
752 |
|
|
|
753 |
|
|
sunos_solib_create_inferior_hook -- shared library startup support
|
754 |
|
|
|
755 |
|
|
SYNOPSIS
|
756 |
|
|
|
757 |
|
|
void sunos_solib_create_inferior_hook()
|
758 |
|
|
|
759 |
|
|
DESCRIPTION
|
760 |
|
|
|
761 |
|
|
When gdb starts up the inferior, it nurses it along (through the
|
762 |
|
|
shell) until it is ready to execute it's first instruction. At this
|
763 |
|
|
point, this function gets called via expansion of the macro
|
764 |
|
|
SOLIB_CREATE_INFERIOR_HOOK.
|
765 |
|
|
|
766 |
|
|
For SunOS executables, this first instruction is typically the
|
767 |
|
|
one at "_start", or a similar text label, regardless of whether
|
768 |
|
|
the executable is statically or dynamically linked. The runtime
|
769 |
|
|
startup code takes care of dynamically linking in any shared
|
770 |
|
|
libraries, once gdb allows the inferior to continue.
|
771 |
|
|
|
772 |
|
|
For SVR4 executables, this first instruction is either the first
|
773 |
|
|
instruction in the dynamic linker (for dynamically linked
|
774 |
|
|
executables) or the instruction at "start" for statically linked
|
775 |
|
|
executables. For dynamically linked executables, the system
|
776 |
|
|
first exec's /lib/libc.so.N, which contains the dynamic linker,
|
777 |
|
|
and starts it running. The dynamic linker maps in any needed
|
778 |
|
|
shared libraries, maps in the actual user executable, and then
|
779 |
|
|
jumps to "start" in the user executable.
|
780 |
|
|
|
781 |
|
|
For both SunOS shared libraries, and SVR4 shared libraries, we
|
782 |
|
|
can arrange to cooperate with the dynamic linker to discover the
|
783 |
|
|
names of shared libraries that are dynamically linked, and the
|
784 |
|
|
base addresses to which they are linked.
|
785 |
|
|
|
786 |
|
|
This function is responsible for discovering those names and
|
787 |
|
|
addresses, and saving sufficient information about them to allow
|
788 |
|
|
their symbols to be read at a later time.
|
789 |
|
|
|
790 |
|
|
FIXME
|
791 |
|
|
|
792 |
|
|
Between enable_break() and disable_break(), this code does not
|
793 |
|
|
properly handle hitting breakpoints which the user might have
|
794 |
|
|
set in the startup code or in the dynamic linker itself. Proper
|
795 |
|
|
handling will probably have to wait until the implementation is
|
796 |
|
|
changed to use the "breakpoint handler function" method.
|
797 |
|
|
|
798 |
|
|
Also, what if child has exit()ed? Must exit loop somehow.
|
799 |
|
|
*/
|
800 |
|
|
|
801 |
|
|
static void
|
802 |
|
|
sunos_solib_create_inferior_hook (void)
|
803 |
|
|
{
|
804 |
|
|
/* Relocate the main executable if necessary. */
|
805 |
|
|
sunos_relocate_main_executable ();
|
806 |
|
|
|
807 |
|
|
if ((debug_base = locate_base ()) == 0)
|
808 |
|
|
{
|
809 |
|
|
/* Can't find the symbol or the executable is statically linked. */
|
810 |
|
|
return;
|
811 |
|
|
}
|
812 |
|
|
|
813 |
|
|
if (!enable_break ())
|
814 |
|
|
{
|
815 |
|
|
warning ("shared library handler failed to enable breakpoint");
|
816 |
|
|
return;
|
817 |
|
|
}
|
818 |
|
|
|
819 |
|
|
/* SCO and SunOS need the loop below, other systems should be using the
|
820 |
|
|
special shared library breakpoints and the shared library breakpoint
|
821 |
|
|
service routine.
|
822 |
|
|
|
823 |
|
|
Now run the target. It will eventually hit the breakpoint, at
|
824 |
|
|
which point all of the libraries will have been mapped in and we
|
825 |
|
|
can go groveling around in the dynamic linker structures to find
|
826 |
|
|
out what we need to know about them. */
|
827 |
|
|
|
828 |
|
|
clear_proceed_status ();
|
829 |
|
|
stop_soon_quietly = 1;
|
830 |
|
|
stop_signal = TARGET_SIGNAL_0;
|
831 |
|
|
do
|
832 |
|
|
{
|
833 |
|
|
target_resume (pid_to_ptid (-1), 0, stop_signal);
|
834 |
|
|
wait_for_inferior ();
|
835 |
|
|
}
|
836 |
|
|
while (stop_signal != TARGET_SIGNAL_TRAP);
|
837 |
|
|
stop_soon_quietly = 0;
|
838 |
|
|
|
839 |
|
|
/* We are now either at the "mapping complete" breakpoint (or somewhere
|
840 |
|
|
else, a condition we aren't prepared to deal with anyway), so adjust
|
841 |
|
|
the PC as necessary after a breakpoint, disable the breakpoint, and
|
842 |
|
|
add any shared libraries that were mapped in. */
|
843 |
|
|
|
844 |
|
|
if (DECR_PC_AFTER_BREAK)
|
845 |
|
|
{
|
846 |
|
|
stop_pc -= DECR_PC_AFTER_BREAK;
|
847 |
|
|
write_register (PC_REGNUM, stop_pc);
|
848 |
|
|
}
|
849 |
|
|
|
850 |
|
|
if (!disable_break ())
|
851 |
|
|
{
|
852 |
|
|
warning ("shared library handler failed to disable breakpoint");
|
853 |
|
|
}
|
854 |
|
|
|
855 |
|
|
solib_add ((char *) 0, 0, (struct target_ops *) 0, auto_solib_add);
|
856 |
|
|
}
|
857 |
|
|
|
858 |
|
|
static void
|
859 |
|
|
sunos_clear_solib (void)
|
860 |
|
|
{
|
861 |
|
|
debug_base = 0;
|
862 |
|
|
}
|
863 |
|
|
|
864 |
|
|
static void
|
865 |
|
|
sunos_free_so (struct so_list *so)
|
866 |
|
|
{
|
867 |
|
|
xfree (so->lm_info->lm);
|
868 |
|
|
xfree (so->lm_info);
|
869 |
|
|
}
|
870 |
|
|
|
871 |
|
|
static void
|
872 |
|
|
sunos_relocate_section_addresses (struct so_list *so,
|
873 |
|
|
struct section_table *sec)
|
874 |
|
|
{
|
875 |
|
|
sec->addr += LM_ADDR (so);
|
876 |
|
|
sec->endaddr += LM_ADDR (so);
|
877 |
|
|
}
|
878 |
|
|
|
879 |
|
|
static struct target_so_ops sunos_so_ops;
|
880 |
|
|
|
881 |
|
|
void
|
882 |
|
|
_initialize_sunos_solib (void)
|
883 |
|
|
{
|
884 |
|
|
sunos_so_ops.relocate_section_addresses = sunos_relocate_section_addresses;
|
885 |
|
|
sunos_so_ops.free_so = sunos_free_so;
|
886 |
|
|
sunos_so_ops.clear_solib = sunos_clear_solib;
|
887 |
|
|
sunos_so_ops.solib_create_inferior_hook = sunos_solib_create_inferior_hook;
|
888 |
|
|
sunos_so_ops.special_symbol_handling = sunos_special_symbol_handling;
|
889 |
|
|
sunos_so_ops.current_sos = sunos_current_sos;
|
890 |
|
|
sunos_so_ops.open_symbol_file_object = open_symbol_file_object;
|
891 |
|
|
sunos_so_ops.in_dynsym_resolve_code = sunos_in_dynsym_resolve_code;
|
892 |
|
|
|
893 |
|
|
/* FIXME: Don't do this here. *_gdbarch_init() should set so_ops. */
|
894 |
|
|
current_target_so_ops = &sunos_so_ops;
|
895 |
|
|
}
|