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1181 |
sfurman |
/* Handle SVR4 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 "elf/external.h"
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#include "elf/common.h"
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#include "elf/mips.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 "target.h"
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#include "inferior.h"
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#include "solist.h"
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#include "solib-svr4.h"
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#ifndef SVR4_FETCH_LINK_MAP_OFFSETS
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#define SVR4_FETCH_LINK_MAP_OFFSETS() svr4_fetch_link_map_offsets ()
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#endif
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static struct link_map_offsets *svr4_fetch_link_map_offsets (void);
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static struct link_map_offsets *legacy_fetch_link_map_offsets (void);
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/* fetch_link_map_offsets_gdbarch_data is a handle used to obtain the
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architecture specific link map offsets fetching function. */
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static struct gdbarch_data *fetch_link_map_offsets_gdbarch_data;
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/* legacy_svr4_fetch_link_map_offsets_hook is a pointer to a function
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which is used to fetch link map offsets. It will only be set
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by solib-legacy.c, if at all. */
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struct link_map_offsets *(*legacy_svr4_fetch_link_map_offsets_hook)(void) = 0;
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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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/* On SVR4 systems, a list of symbols in the dynamic linker where
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GDB can try to place a breakpoint to monitor shared library
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events.
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If none of these symbols are found, or other errors occur, then
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SVR4 systems will fall back to using a symbol as the "startup
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mapping complete" breakpoint address. */
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static char *solib_break_names[] =
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{
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"r_debug_state",
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"_r_debug_state",
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"_dl_debug_state",
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"rtld_db_dlactivity",
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"_rtld_debug_state",
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NULL
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};
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#define BKPT_AT_SYMBOL 1
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#if defined (BKPT_AT_SYMBOL)
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static char *bkpt_names[] =
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{
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#ifdef SOLIB_BKPT_NAME
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SOLIB_BKPT_NAME, /* Prefer configured name if it exists. */
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#endif
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"_start",
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"__start",
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"main",
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NULL
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};
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#endif
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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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/* 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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struct link_map_offsets *lmo = SVR4_FETCH_LINK_MAP_OFFSETS ();
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return (CORE_ADDR) extract_signed_integer (so->lm_info->lm + lmo->l_addr_offset,
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lmo->l_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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struct link_map_offsets *lmo = SVR4_FETCH_LINK_MAP_OFFSETS ();
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return extract_address (so->lm_info->lm + lmo->l_next_offset, lmo->l_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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struct link_map_offsets *lmo = SVR4_FETCH_LINK_MAP_OFFSETS ();
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return extract_address (so->lm_info->lm + lmo->l_name_offset, lmo->l_name_size);
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}
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static int
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IGNORE_FIRST_LINK_MAP_ENTRY (struct so_list *so)
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{
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struct link_map_offsets *lmo = SVR4_FETCH_LINK_MAP_OFFSETS ();
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return extract_address (so->lm_info->lm + lmo->l_prev_offset,
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lmo->l_prev_size) == 0;
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}
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static CORE_ADDR debug_base; /* Base of dynamic linker structures */
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static CORE_ADDR breakpoint_addr; /* Address where end bkpt is set */
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/* Local function prototypes */
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static int match_main (char *);
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static CORE_ADDR bfd_lookup_symbol (bfd *, char *);
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/*
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LOCAL FUNCTION
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bfd_lookup_symbol -- lookup the value for a specific symbol
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SYNOPSIS
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CORE_ADDR bfd_lookup_symbol (bfd *abfd, char *symname)
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DESCRIPTION
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An expensive way to lookup the value of a single symbol for
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bfd's that are only temporary anyway. This is used by the
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shared library support to find the address of the debugger
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interface structures in the shared library.
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Note that 0 is specifically allowed as an error return (no
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such symbol).
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*/
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static CORE_ADDR
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bfd_lookup_symbol (bfd *abfd, char *symname)
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{
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long storage_needed;
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asymbol *sym;
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asymbol **symbol_table;
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unsigned int number_of_symbols;
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unsigned int i;
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struct cleanup *back_to;
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CORE_ADDR symaddr = 0;
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storage_needed = bfd_get_symtab_upper_bound (abfd);
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if (storage_needed > 0)
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{
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symbol_table = (asymbol **) xmalloc (storage_needed);
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back_to = make_cleanup (xfree, (PTR) symbol_table);
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number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table);
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for (i = 0; i < number_of_symbols; i++)
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{
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sym = *symbol_table++;
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if (STREQ (sym->name, symname))
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{
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/* Bfd symbols are section relative. */
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symaddr = sym->value + sym->section->vma;
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break;
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}
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}
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do_cleanups (back_to);
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}
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if (symaddr)
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return symaddr;
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/* On FreeBSD, the dynamic linker is stripped by default. So we'll
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have to check the dynamic string table too. */
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storage_needed = bfd_get_dynamic_symtab_upper_bound (abfd);
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if (storage_needed > 0)
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{
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symbol_table = (asymbol **) xmalloc (storage_needed);
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back_to = make_cleanup (xfree, (PTR) symbol_table);
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number_of_symbols = bfd_canonicalize_dynamic_symtab (abfd, symbol_table);
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for (i = 0; i < number_of_symbols; i++)
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{
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sym = *symbol_table++;
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if (STREQ (sym->name, symname))
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{
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/* Bfd symbols are section relative. */
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symaddr = sym->value + sym->section->vma;
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break;
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}
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}
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do_cleanups (back_to);
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}
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return symaddr;
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}
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#ifdef HANDLE_SVR4_EXEC_EMULATORS
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/*
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Solaris BCP (the part of Solaris which allows it to run SunOS4
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a.out files) throws in another wrinkle. Solaris does not fill
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in the usual a.out link map structures when running BCP programs,
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the only way to get at them is via groping around in the dynamic
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linker.
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The dynamic linker and it's structures are located in the shared
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C library, which gets run as the executable's "interpreter" by
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the kernel.
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Note that we can assume nothing about the process state at the time
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we need to find these structures. We may be stopped on the first
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instruction of the interpreter (C shared library), the first
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instruction of the executable itself, or somewhere else entirely
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(if we attached to the process for example).
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*/
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static char *debug_base_symbols[] =
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{
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"r_debug", /* Solaris 2.3 */
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"_r_debug", /* Solaris 2.1, 2.2 */
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NULL
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};
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271 |
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272 |
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static int look_for_base (int, CORE_ADDR);
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274 |
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/*
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275 |
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276 |
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LOCAL FUNCTION
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278 |
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look_for_base -- examine file for each mapped address segment
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279 |
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280 |
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SYNOPSYS
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282 |
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static int look_for_base (int fd, CORE_ADDR baseaddr)
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284 |
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DESCRIPTION
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285 |
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286 |
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This function is passed to proc_iterate_over_mappings, which
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causes it to get called once for each mapped address space, with
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288 |
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an open file descriptor for the file mapped to that space, and the
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base address of that mapped space.
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290 |
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291 |
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Our job is to find the debug base symbol in the file that this
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fd is open on, if it exists, and if so, initialize the dynamic
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293 |
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linker structure base address debug_base.
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294 |
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295 |
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Note that this is a computationally expensive proposition, since
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296 |
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we basically have to open a bfd on every call, so we specifically
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297 |
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avoid opening the exec file.
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298 |
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*/
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299 |
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300 |
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static int
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301 |
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look_for_base (int fd, CORE_ADDR baseaddr)
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302 |
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{
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303 |
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bfd *interp_bfd;
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304 |
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CORE_ADDR address = 0;
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305 |
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char **symbolp;
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306 |
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307 |
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/* If the fd is -1, then there is no file that corresponds to this
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308 |
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mapped memory segment, so skip it. Also, if the fd corresponds
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309 |
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to the exec file, skip it as well. */
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310 |
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311 |
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if (fd == -1
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312 |
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|| (exec_bfd != NULL
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313 |
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&& fdmatch (fileno ((FILE *) (exec_bfd->iostream)), fd)))
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314 |
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{
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315 |
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return (0);
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316 |
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}
|
317 |
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|
318 |
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/* Try to open whatever random file this fd corresponds to. Note that
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319 |
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we have no way currently to find the filename. Don't gripe about
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320 |
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any problems we might have, just fail. */
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321 |
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|
322 |
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if ((interp_bfd = bfd_fdopenr ("unnamed", gnutarget, fd)) == NULL)
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323 |
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{
|
324 |
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return (0);
|
325 |
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}
|
326 |
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if (!bfd_check_format (interp_bfd, bfd_object))
|
327 |
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{
|
328 |
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/* FIXME-leak: on failure, might not free all memory associated with
|
329 |
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interp_bfd. */
|
330 |
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bfd_close (interp_bfd);
|
331 |
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return (0);
|
332 |
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}
|
333 |
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|
334 |
|
|
/* Now try to find our debug base symbol in this file, which we at
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335 |
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least know to be a valid ELF executable or shared library. */
|
336 |
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|
337 |
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for (symbolp = debug_base_symbols; *symbolp != NULL; symbolp++)
|
338 |
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{
|
339 |
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address = bfd_lookup_symbol (interp_bfd, *symbolp);
|
340 |
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if (address != 0)
|
341 |
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{
|
342 |
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break;
|
343 |
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}
|
344 |
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}
|
345 |
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if (address == 0)
|
346 |
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{
|
347 |
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/* FIXME-leak: on failure, might not free all memory associated with
|
348 |
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interp_bfd. */
|
349 |
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bfd_close (interp_bfd);
|
350 |
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return (0);
|
351 |
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}
|
352 |
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|
353 |
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/* Eureka! We found the symbol. But now we may need to relocate it
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354 |
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by the base address. If the symbol's value is less than the base
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355 |
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address of the shared library, then it hasn't yet been relocated
|
356 |
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|
by the dynamic linker, and we have to do it ourself. FIXME: Note
|
357 |
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|
that we make the assumption that the first segment that corresponds
|
358 |
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|
to the shared library has the base address to which the library
|
359 |
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|
was relocated. */
|
360 |
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|
361 |
|
|
if (address < baseaddr)
|
362 |
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{
|
363 |
|
|
address += baseaddr;
|
364 |
|
|
}
|
365 |
|
|
debug_base = address;
|
366 |
|
|
/* FIXME-leak: on failure, might not free all memory associated with
|
367 |
|
|
interp_bfd. */
|
368 |
|
|
bfd_close (interp_bfd);
|
369 |
|
|
return (1);
|
370 |
|
|
}
|
371 |
|
|
#endif /* HANDLE_SVR4_EXEC_EMULATORS */
|
372 |
|
|
|
373 |
|
|
/*
|
374 |
|
|
|
375 |
|
|
LOCAL FUNCTION
|
376 |
|
|
|
377 |
|
|
elf_locate_base -- locate the base address of dynamic linker structs
|
378 |
|
|
for SVR4 elf targets.
|
379 |
|
|
|
380 |
|
|
SYNOPSIS
|
381 |
|
|
|
382 |
|
|
CORE_ADDR elf_locate_base (void)
|
383 |
|
|
|
384 |
|
|
DESCRIPTION
|
385 |
|
|
|
386 |
|
|
For SVR4 elf targets the address of the dynamic linker's runtime
|
387 |
|
|
structure is contained within the dynamic info section in the
|
388 |
|
|
executable file. The dynamic section is also mapped into the
|
389 |
|
|
inferior address space. Because the runtime loader fills in the
|
390 |
|
|
real address before starting the inferior, we have to read in the
|
391 |
|
|
dynamic info section from the inferior address space.
|
392 |
|
|
If there are any errors while trying to find the address, we
|
393 |
|
|
silently return 0, otherwise the found address is returned.
|
394 |
|
|
|
395 |
|
|
*/
|
396 |
|
|
|
397 |
|
|
static CORE_ADDR
|
398 |
|
|
elf_locate_base (void)
|
399 |
|
|
{
|
400 |
|
|
sec_ptr dyninfo_sect;
|
401 |
|
|
int dyninfo_sect_size;
|
402 |
|
|
CORE_ADDR dyninfo_addr;
|
403 |
|
|
char *buf;
|
404 |
|
|
char *bufend;
|
405 |
|
|
int arch_size;
|
406 |
|
|
|
407 |
|
|
/* Find the start address of the .dynamic section. */
|
408 |
|
|
dyninfo_sect = bfd_get_section_by_name (exec_bfd, ".dynamic");
|
409 |
|
|
if (dyninfo_sect == NULL)
|
410 |
|
|
return 0;
|
411 |
|
|
dyninfo_addr = bfd_section_vma (exec_bfd, dyninfo_sect);
|
412 |
|
|
|
413 |
|
|
/* Read in .dynamic section, silently ignore errors. */
|
414 |
|
|
dyninfo_sect_size = bfd_section_size (exec_bfd, dyninfo_sect);
|
415 |
|
|
buf = alloca (dyninfo_sect_size);
|
416 |
|
|
if (target_read_memory (dyninfo_addr, buf, dyninfo_sect_size))
|
417 |
|
|
return 0;
|
418 |
|
|
|
419 |
|
|
/* Find the DT_DEBUG entry in the the .dynamic section.
|
420 |
|
|
For mips elf we look for DT_MIPS_RLD_MAP, mips elf apparently has
|
421 |
|
|
no DT_DEBUG entries. */
|
422 |
|
|
|
423 |
|
|
arch_size = bfd_get_arch_size (exec_bfd);
|
424 |
|
|
if (arch_size == -1) /* failure */
|
425 |
|
|
return 0;
|
426 |
|
|
|
427 |
|
|
if (arch_size == 32)
|
428 |
|
|
{ /* 32-bit elf */
|
429 |
|
|
for (bufend = buf + dyninfo_sect_size;
|
430 |
|
|
buf < bufend;
|
431 |
|
|
buf += sizeof (Elf32_External_Dyn))
|
432 |
|
|
{
|
433 |
|
|
Elf32_External_Dyn *x_dynp = (Elf32_External_Dyn *) buf;
|
434 |
|
|
long dyn_tag;
|
435 |
|
|
CORE_ADDR dyn_ptr;
|
436 |
|
|
|
437 |
|
|
dyn_tag = bfd_h_get_32 (exec_bfd, (bfd_byte *) x_dynp->d_tag);
|
438 |
|
|
if (dyn_tag == DT_NULL)
|
439 |
|
|
break;
|
440 |
|
|
else if (dyn_tag == DT_DEBUG)
|
441 |
|
|
{
|
442 |
|
|
dyn_ptr = bfd_h_get_32 (exec_bfd,
|
443 |
|
|
(bfd_byte *) x_dynp->d_un.d_ptr);
|
444 |
|
|
return dyn_ptr;
|
445 |
|
|
}
|
446 |
|
|
else if (dyn_tag == DT_MIPS_RLD_MAP)
|
447 |
|
|
{
|
448 |
|
|
char *pbuf;
|
449 |
|
|
|
450 |
|
|
pbuf = alloca (TARGET_PTR_BIT / HOST_CHAR_BIT);
|
451 |
|
|
/* DT_MIPS_RLD_MAP contains a pointer to the address
|
452 |
|
|
of the dynamic link structure. */
|
453 |
|
|
dyn_ptr = bfd_h_get_32 (exec_bfd,
|
454 |
|
|
(bfd_byte *) x_dynp->d_un.d_ptr);
|
455 |
|
|
if (target_read_memory (dyn_ptr, pbuf, sizeof (pbuf)))
|
456 |
|
|
return 0;
|
457 |
|
|
return extract_unsigned_integer (pbuf, sizeof (pbuf));
|
458 |
|
|
}
|
459 |
|
|
}
|
460 |
|
|
}
|
461 |
|
|
else /* 64-bit elf */
|
462 |
|
|
{
|
463 |
|
|
for (bufend = buf + dyninfo_sect_size;
|
464 |
|
|
buf < bufend;
|
465 |
|
|
buf += sizeof (Elf64_External_Dyn))
|
466 |
|
|
{
|
467 |
|
|
Elf64_External_Dyn *x_dynp = (Elf64_External_Dyn *) buf;
|
468 |
|
|
long dyn_tag;
|
469 |
|
|
CORE_ADDR dyn_ptr;
|
470 |
|
|
|
471 |
|
|
dyn_tag = bfd_h_get_64 (exec_bfd, (bfd_byte *) x_dynp->d_tag);
|
472 |
|
|
if (dyn_tag == DT_NULL)
|
473 |
|
|
break;
|
474 |
|
|
else if (dyn_tag == DT_DEBUG)
|
475 |
|
|
{
|
476 |
|
|
dyn_ptr = bfd_h_get_64 (exec_bfd,
|
477 |
|
|
(bfd_byte *) x_dynp->d_un.d_ptr);
|
478 |
|
|
return dyn_ptr;
|
479 |
|
|
}
|
480 |
|
|
}
|
481 |
|
|
}
|
482 |
|
|
|
483 |
|
|
/* DT_DEBUG entry not found. */
|
484 |
|
|
return 0;
|
485 |
|
|
}
|
486 |
|
|
|
487 |
|
|
/*
|
488 |
|
|
|
489 |
|
|
LOCAL FUNCTION
|
490 |
|
|
|
491 |
|
|
locate_base -- locate the base address of dynamic linker structs
|
492 |
|
|
|
493 |
|
|
SYNOPSIS
|
494 |
|
|
|
495 |
|
|
CORE_ADDR locate_base (void)
|
496 |
|
|
|
497 |
|
|
DESCRIPTION
|
498 |
|
|
|
499 |
|
|
For both the SunOS and SVR4 shared library implementations, if the
|
500 |
|
|
inferior executable has been linked dynamically, there is a single
|
501 |
|
|
address somewhere in the inferior's data space which is the key to
|
502 |
|
|
locating all of the dynamic linker's runtime structures. This
|
503 |
|
|
address is the value of the debug base symbol. The job of this
|
504 |
|
|
function is to find and return that address, or to return 0 if there
|
505 |
|
|
is no such address (the executable is statically linked for example).
|
506 |
|
|
|
507 |
|
|
For SunOS, the job is almost trivial, since the dynamic linker and
|
508 |
|
|
all of it's structures are statically linked to the executable at
|
509 |
|
|
link time. Thus the symbol for the address we are looking for has
|
510 |
|
|
already been added to the minimal symbol table for the executable's
|
511 |
|
|
objfile at the time the symbol file's symbols were read, and all we
|
512 |
|
|
have to do is look it up there. Note that we explicitly do NOT want
|
513 |
|
|
to find the copies in the shared library.
|
514 |
|
|
|
515 |
|
|
The SVR4 version is a bit more complicated because the address
|
516 |
|
|
is contained somewhere in the dynamic info section. We have to go
|
517 |
|
|
to a lot more work to discover the address of the debug base symbol.
|
518 |
|
|
Because of this complexity, we cache the value we find and return that
|
519 |
|
|
value on subsequent invocations. Note there is no copy in the
|
520 |
|
|
executable symbol tables.
|
521 |
|
|
|
522 |
|
|
*/
|
523 |
|
|
|
524 |
|
|
static CORE_ADDR
|
525 |
|
|
locate_base (void)
|
526 |
|
|
{
|
527 |
|
|
/* Check to see if we have a currently valid address, and if so, avoid
|
528 |
|
|
doing all this work again and just return the cached address. If
|
529 |
|
|
we have no cached address, try to locate it in the dynamic info
|
530 |
|
|
section for ELF executables. */
|
531 |
|
|
|
532 |
|
|
if (debug_base == 0)
|
533 |
|
|
{
|
534 |
|
|
if (exec_bfd != NULL
|
535 |
|
|
&& bfd_get_flavour (exec_bfd) == bfd_target_elf_flavour)
|
536 |
|
|
debug_base = elf_locate_base ();
|
537 |
|
|
#ifdef HANDLE_SVR4_EXEC_EMULATORS
|
538 |
|
|
/* Try it the hard way for emulated executables. */
|
539 |
|
|
else if (!ptid_equal (inferior_ptid, null_ptid) && target_has_execution)
|
540 |
|
|
proc_iterate_over_mappings (look_for_base);
|
541 |
|
|
#endif
|
542 |
|
|
}
|
543 |
|
|
return (debug_base);
|
544 |
|
|
}
|
545 |
|
|
|
546 |
|
|
/*
|
547 |
|
|
|
548 |
|
|
LOCAL FUNCTION
|
549 |
|
|
|
550 |
|
|
first_link_map_member -- locate first member in dynamic linker's map
|
551 |
|
|
|
552 |
|
|
SYNOPSIS
|
553 |
|
|
|
554 |
|
|
static CORE_ADDR first_link_map_member (void)
|
555 |
|
|
|
556 |
|
|
DESCRIPTION
|
557 |
|
|
|
558 |
|
|
Find the first element in the inferior's dynamic link map, and
|
559 |
|
|
return its address in the inferior. This function doesn't copy the
|
560 |
|
|
link map entry itself into our address space; current_sos actually
|
561 |
|
|
does the reading. */
|
562 |
|
|
|
563 |
|
|
static CORE_ADDR
|
564 |
|
|
first_link_map_member (void)
|
565 |
|
|
{
|
566 |
|
|
CORE_ADDR lm = 0;
|
567 |
|
|
struct link_map_offsets *lmo = SVR4_FETCH_LINK_MAP_OFFSETS ();
|
568 |
|
|
char *r_map_buf = xmalloc (lmo->r_map_size);
|
569 |
|
|
struct cleanup *cleanups = make_cleanup (xfree, r_map_buf);
|
570 |
|
|
|
571 |
|
|
read_memory (debug_base + lmo->r_map_offset, r_map_buf, lmo->r_map_size);
|
572 |
|
|
|
573 |
|
|
lm = extract_address (r_map_buf, lmo->r_map_size);
|
574 |
|
|
|
575 |
|
|
/* FIXME: Perhaps we should validate the info somehow, perhaps by
|
576 |
|
|
checking r_version for a known version number, or r_state for
|
577 |
|
|
RT_CONSISTENT. */
|
578 |
|
|
|
579 |
|
|
do_cleanups (cleanups);
|
580 |
|
|
|
581 |
|
|
return (lm);
|
582 |
|
|
}
|
583 |
|
|
|
584 |
|
|
/*
|
585 |
|
|
|
586 |
|
|
LOCAL FUNCTION
|
587 |
|
|
|
588 |
|
|
open_symbol_file_object
|
589 |
|
|
|
590 |
|
|
SYNOPSIS
|
591 |
|
|
|
592 |
|
|
void open_symbol_file_object (void *from_tty)
|
593 |
|
|
|
594 |
|
|
DESCRIPTION
|
595 |
|
|
|
596 |
|
|
If no open symbol file, attempt to locate and open the main symbol
|
597 |
|
|
file. On SVR4 systems, this is the first link map entry. If its
|
598 |
|
|
name is here, we can open it. Useful when attaching to a process
|
599 |
|
|
without first loading its symbol file.
|
600 |
|
|
|
601 |
|
|
If FROM_TTYP dereferences to a non-zero integer, allow messages to
|
602 |
|
|
be printed. This parameter is a pointer rather than an int because
|
603 |
|
|
open_symbol_file_object() is called via catch_errors() and
|
604 |
|
|
catch_errors() requires a pointer argument. */
|
605 |
|
|
|
606 |
|
|
static int
|
607 |
|
|
open_symbol_file_object (void *from_ttyp)
|
608 |
|
|
{
|
609 |
|
|
CORE_ADDR lm, l_name;
|
610 |
|
|
char *filename;
|
611 |
|
|
int errcode;
|
612 |
|
|
int from_tty = *(int *)from_ttyp;
|
613 |
|
|
struct link_map_offsets *lmo = SVR4_FETCH_LINK_MAP_OFFSETS ();
|
614 |
|
|
char *l_name_buf = xmalloc (lmo->l_name_size);
|
615 |
|
|
struct cleanup *cleanups = make_cleanup (xfree, l_name_buf);
|
616 |
|
|
|
617 |
|
|
if (symfile_objfile)
|
618 |
|
|
if (!query ("Attempt to reload symbols from process? "))
|
619 |
|
|
return 0;
|
620 |
|
|
|
621 |
|
|
if ((debug_base = locate_base ()) == 0)
|
622 |
|
|
return 0; /* failed somehow... */
|
623 |
|
|
|
624 |
|
|
/* First link map member should be the executable. */
|
625 |
|
|
if ((lm = first_link_map_member ()) == 0)
|
626 |
|
|
return 0; /* failed somehow... */
|
627 |
|
|
|
628 |
|
|
/* Read address of name from target memory to GDB. */
|
629 |
|
|
read_memory (lm + lmo->l_name_offset, l_name_buf, lmo->l_name_size);
|
630 |
|
|
|
631 |
|
|
/* Convert the address to host format. */
|
632 |
|
|
l_name = extract_address (l_name_buf, lmo->l_name_size);
|
633 |
|
|
|
634 |
|
|
/* Free l_name_buf. */
|
635 |
|
|
do_cleanups (cleanups);
|
636 |
|
|
|
637 |
|
|
if (l_name == 0)
|
638 |
|
|
return 0; /* No filename. */
|
639 |
|
|
|
640 |
|
|
/* Now fetch the filename from target memory. */
|
641 |
|
|
target_read_string (l_name, &filename, SO_NAME_MAX_PATH_SIZE - 1, &errcode);
|
642 |
|
|
|
643 |
|
|
if (errcode)
|
644 |
|
|
{
|
645 |
|
|
warning ("failed to read exec filename from attached file: %s",
|
646 |
|
|
safe_strerror (errcode));
|
647 |
|
|
return 0;
|
648 |
|
|
}
|
649 |
|
|
|
650 |
|
|
make_cleanup (xfree, filename);
|
651 |
|
|
/* Have a pathname: read the symbol file. */
|
652 |
|
|
symbol_file_add_main (filename, from_tty);
|
653 |
|
|
|
654 |
|
|
return 1;
|
655 |
|
|
}
|
656 |
|
|
|
657 |
|
|
/* LOCAL FUNCTION
|
658 |
|
|
|
659 |
|
|
current_sos -- build a list of currently loaded shared objects
|
660 |
|
|
|
661 |
|
|
SYNOPSIS
|
662 |
|
|
|
663 |
|
|
struct so_list *current_sos ()
|
664 |
|
|
|
665 |
|
|
DESCRIPTION
|
666 |
|
|
|
667 |
|
|
Build a list of `struct so_list' objects describing the shared
|
668 |
|
|
objects currently loaded in the inferior. This list does not
|
669 |
|
|
include an entry for the main executable file.
|
670 |
|
|
|
671 |
|
|
Note that we only gather information directly available from the
|
672 |
|
|
inferior --- we don't examine any of the shared library files
|
673 |
|
|
themselves. The declaration of `struct so_list' says which fields
|
674 |
|
|
we provide values for. */
|
675 |
|
|
|
676 |
|
|
static struct so_list *
|
677 |
|
|
svr4_current_sos (void)
|
678 |
|
|
{
|
679 |
|
|
CORE_ADDR lm;
|
680 |
|
|
struct so_list *head = 0;
|
681 |
|
|
struct so_list **link_ptr = &head;
|
682 |
|
|
|
683 |
|
|
/* Make sure we've looked up the inferior's dynamic linker's base
|
684 |
|
|
structure. */
|
685 |
|
|
if (! debug_base)
|
686 |
|
|
{
|
687 |
|
|
debug_base = locate_base ();
|
688 |
|
|
|
689 |
|
|
/* If we can't find the dynamic linker's base structure, this
|
690 |
|
|
must not be a dynamically linked executable. Hmm. */
|
691 |
|
|
if (! debug_base)
|
692 |
|
|
return 0;
|
693 |
|
|
}
|
694 |
|
|
|
695 |
|
|
/* Walk the inferior's link map list, and build our list of
|
696 |
|
|
`struct so_list' nodes. */
|
697 |
|
|
lm = first_link_map_member ();
|
698 |
|
|
while (lm)
|
699 |
|
|
{
|
700 |
|
|
struct link_map_offsets *lmo = SVR4_FETCH_LINK_MAP_OFFSETS ();
|
701 |
|
|
struct so_list *new
|
702 |
|
|
= (struct so_list *) xmalloc (sizeof (struct so_list));
|
703 |
|
|
struct cleanup *old_chain = make_cleanup (xfree, new);
|
704 |
|
|
|
705 |
|
|
memset (new, 0, sizeof (*new));
|
706 |
|
|
|
707 |
|
|
new->lm_info = xmalloc (sizeof (struct lm_info));
|
708 |
|
|
make_cleanup (xfree, new->lm_info);
|
709 |
|
|
|
710 |
|
|
new->lm_info->lm = xmalloc (lmo->link_map_size);
|
711 |
|
|
make_cleanup (xfree, new->lm_info->lm);
|
712 |
|
|
memset (new->lm_info->lm, 0, lmo->link_map_size);
|
713 |
|
|
|
714 |
|
|
read_memory (lm, new->lm_info->lm, lmo->link_map_size);
|
715 |
|
|
|
716 |
|
|
lm = LM_NEXT (new);
|
717 |
|
|
|
718 |
|
|
/* For SVR4 versions, the first entry in the link map is for the
|
719 |
|
|
inferior executable, so we must ignore it. For some versions of
|
720 |
|
|
SVR4, it has no name. For others (Solaris 2.3 for example), it
|
721 |
|
|
does have a name, so we can no longer use a missing name to
|
722 |
|
|
decide when to ignore it. */
|
723 |
|
|
if (IGNORE_FIRST_LINK_MAP_ENTRY (new))
|
724 |
|
|
free_so (new);
|
725 |
|
|
else
|
726 |
|
|
{
|
727 |
|
|
int errcode;
|
728 |
|
|
char *buffer;
|
729 |
|
|
|
730 |
|
|
/* Extract this shared object's name. */
|
731 |
|
|
target_read_string (LM_NAME (new), &buffer,
|
732 |
|
|
SO_NAME_MAX_PATH_SIZE - 1, &errcode);
|
733 |
|
|
if (errcode != 0)
|
734 |
|
|
{
|
735 |
|
|
warning ("current_sos: Can't read pathname for load map: %s\n",
|
736 |
|
|
safe_strerror (errcode));
|
737 |
|
|
}
|
738 |
|
|
else
|
739 |
|
|
{
|
740 |
|
|
strncpy (new->so_name, buffer, SO_NAME_MAX_PATH_SIZE - 1);
|
741 |
|
|
new->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0';
|
742 |
|
|
xfree (buffer);
|
743 |
|
|
strcpy (new->so_original_name, new->so_name);
|
744 |
|
|
}
|
745 |
|
|
|
746 |
|
|
/* If this entry has no name, or its name matches the name
|
747 |
|
|
for the main executable, don't include it in the list. */
|
748 |
|
|
if (! new->so_name[0]
|
749 |
|
|
|| match_main (new->so_name))
|
750 |
|
|
free_so (new);
|
751 |
|
|
else
|
752 |
|
|
{
|
753 |
|
|
new->next = 0;
|
754 |
|
|
*link_ptr = new;
|
755 |
|
|
link_ptr = &new->next;
|
756 |
|
|
}
|
757 |
|
|
}
|
758 |
|
|
|
759 |
|
|
discard_cleanups (old_chain);
|
760 |
|
|
}
|
761 |
|
|
|
762 |
|
|
return head;
|
763 |
|
|
}
|
764 |
|
|
|
765 |
|
|
|
766 |
|
|
/* On some systems, the only way to recognize the link map entry for
|
767 |
|
|
the main executable file is by looking at its name. Return
|
768 |
|
|
non-zero iff SONAME matches one of the known main executable names. */
|
769 |
|
|
|
770 |
|
|
static int
|
771 |
|
|
match_main (char *soname)
|
772 |
|
|
{
|
773 |
|
|
char **mainp;
|
774 |
|
|
|
775 |
|
|
for (mainp = main_name_list; *mainp != NULL; mainp++)
|
776 |
|
|
{
|
777 |
|
|
if (strcmp (soname, *mainp) == 0)
|
778 |
|
|
return (1);
|
779 |
|
|
}
|
780 |
|
|
|
781 |
|
|
return (0);
|
782 |
|
|
}
|
783 |
|
|
|
784 |
|
|
/* Return 1 if PC lies in the dynamic symbol resolution code of the
|
785 |
|
|
SVR4 run time loader. */
|
786 |
|
|
static CORE_ADDR interp_text_sect_low;
|
787 |
|
|
static CORE_ADDR interp_text_sect_high;
|
788 |
|
|
static CORE_ADDR interp_plt_sect_low;
|
789 |
|
|
static CORE_ADDR interp_plt_sect_high;
|
790 |
|
|
|
791 |
|
|
static int
|
792 |
|
|
svr4_in_dynsym_resolve_code (CORE_ADDR pc)
|
793 |
|
|
{
|
794 |
|
|
return ((pc >= interp_text_sect_low && pc < interp_text_sect_high)
|
795 |
|
|
|| (pc >= interp_plt_sect_low && pc < interp_plt_sect_high)
|
796 |
|
|
|| in_plt_section (pc, NULL));
|
797 |
|
|
}
|
798 |
|
|
|
799 |
|
|
|
800 |
|
|
/*
|
801 |
|
|
|
802 |
|
|
LOCAL FUNCTION
|
803 |
|
|
|
804 |
|
|
enable_break -- arrange for dynamic linker to hit breakpoint
|
805 |
|
|
|
806 |
|
|
SYNOPSIS
|
807 |
|
|
|
808 |
|
|
int enable_break (void)
|
809 |
|
|
|
810 |
|
|
DESCRIPTION
|
811 |
|
|
|
812 |
|
|
Both the SunOS and the SVR4 dynamic linkers have, as part of their
|
813 |
|
|
debugger interface, support for arranging for the inferior to hit
|
814 |
|
|
a breakpoint after mapping in the shared libraries. This function
|
815 |
|
|
enables that breakpoint.
|
816 |
|
|
|
817 |
|
|
For SunOS, there is a special flag location (in_debugger) which we
|
818 |
|
|
set to 1. When the dynamic linker sees this flag set, it will set
|
819 |
|
|
a breakpoint at a location known only to itself, after saving the
|
820 |
|
|
original contents of that place and the breakpoint address itself,
|
821 |
|
|
in it's own internal structures. When we resume the inferior, it
|
822 |
|
|
will eventually take a SIGTRAP when it runs into the breakpoint.
|
823 |
|
|
We handle this (in a different place) by restoring the contents of
|
824 |
|
|
the breakpointed location (which is only known after it stops),
|
825 |
|
|
chasing around to locate the shared libraries that have been
|
826 |
|
|
loaded, then resuming.
|
827 |
|
|
|
828 |
|
|
For SVR4, the debugger interface structure contains a member (r_brk)
|
829 |
|
|
which is statically initialized at the time the shared library is
|
830 |
|
|
built, to the offset of a function (_r_debug_state) which is guaran-
|
831 |
|
|
teed to be called once before mapping in a library, and again when
|
832 |
|
|
the mapping is complete. At the time we are examining this member,
|
833 |
|
|
it contains only the unrelocated offset of the function, so we have
|
834 |
|
|
to do our own relocation. Later, when the dynamic linker actually
|
835 |
|
|
runs, it relocates r_brk to be the actual address of _r_debug_state().
|
836 |
|
|
|
837 |
|
|
The debugger interface structure also contains an enumeration which
|
838 |
|
|
is set to either RT_ADD or RT_DELETE prior to changing the mapping,
|
839 |
|
|
depending upon whether or not the library is being mapped or unmapped,
|
840 |
|
|
and then set to RT_CONSISTENT after the library is mapped/unmapped.
|
841 |
|
|
*/
|
842 |
|
|
|
843 |
|
|
static int
|
844 |
|
|
enable_break (void)
|
845 |
|
|
{
|
846 |
|
|
int success = 0;
|
847 |
|
|
|
848 |
|
|
#ifdef BKPT_AT_SYMBOL
|
849 |
|
|
|
850 |
|
|
struct minimal_symbol *msymbol;
|
851 |
|
|
char **bkpt_namep;
|
852 |
|
|
asection *interp_sect;
|
853 |
|
|
|
854 |
|
|
/* First, remove all the solib event breakpoints. Their addresses
|
855 |
|
|
may have changed since the last time we ran the program. */
|
856 |
|
|
remove_solib_event_breakpoints ();
|
857 |
|
|
|
858 |
|
|
interp_text_sect_low = interp_text_sect_high = 0;
|
859 |
|
|
interp_plt_sect_low = interp_plt_sect_high = 0;
|
860 |
|
|
|
861 |
|
|
/* Find the .interp section; if not found, warn the user and drop
|
862 |
|
|
into the old breakpoint at symbol code. */
|
863 |
|
|
interp_sect = bfd_get_section_by_name (exec_bfd, ".interp");
|
864 |
|
|
if (interp_sect)
|
865 |
|
|
{
|
866 |
|
|
unsigned int interp_sect_size;
|
867 |
|
|
char *buf;
|
868 |
|
|
CORE_ADDR load_addr = 0;
|
869 |
|
|
int load_addr_found = 0;
|
870 |
|
|
struct so_list *inferior_sos;
|
871 |
|
|
bfd *tmp_bfd = NULL;
|
872 |
|
|
int tmp_fd = -1;
|
873 |
|
|
char *tmp_pathname = NULL;
|
874 |
|
|
CORE_ADDR sym_addr = 0;
|
875 |
|
|
|
876 |
|
|
/* Read the contents of the .interp section into a local buffer;
|
877 |
|
|
the contents specify the dynamic linker this program uses. */
|
878 |
|
|
interp_sect_size = bfd_section_size (exec_bfd, interp_sect);
|
879 |
|
|
buf = alloca (interp_sect_size);
|
880 |
|
|
bfd_get_section_contents (exec_bfd, interp_sect,
|
881 |
|
|
buf, 0, interp_sect_size);
|
882 |
|
|
|
883 |
|
|
/* Now we need to figure out where the dynamic linker was
|
884 |
|
|
loaded so that we can load its symbols and place a breakpoint
|
885 |
|
|
in the dynamic linker itself.
|
886 |
|
|
|
887 |
|
|
This address is stored on the stack. However, I've been unable
|
888 |
|
|
to find any magic formula to find it for Solaris (appears to
|
889 |
|
|
be trivial on GNU/Linux). Therefore, we have to try an alternate
|
890 |
|
|
mechanism to find the dynamic linker's base address. */
|
891 |
|
|
|
892 |
|
|
tmp_fd = solib_open (buf, &tmp_pathname);
|
893 |
|
|
if (tmp_fd >= 0)
|
894 |
|
|
tmp_bfd = bfd_fdopenr (tmp_pathname, gnutarget, tmp_fd);
|
895 |
|
|
|
896 |
|
|
if (tmp_bfd == NULL)
|
897 |
|
|
goto bkpt_at_symbol;
|
898 |
|
|
|
899 |
|
|
/* Make sure the dynamic linker's really a useful object. */
|
900 |
|
|
if (!bfd_check_format (tmp_bfd, bfd_object))
|
901 |
|
|
{
|
902 |
|
|
warning ("Unable to grok dynamic linker %s as an object file", buf);
|
903 |
|
|
bfd_close (tmp_bfd);
|
904 |
|
|
goto bkpt_at_symbol;
|
905 |
|
|
}
|
906 |
|
|
|
907 |
|
|
/* If the entry in _DYNAMIC for the dynamic linker has already
|
908 |
|
|
been filled in, we can read its base address from there. */
|
909 |
|
|
inferior_sos = svr4_current_sos ();
|
910 |
|
|
if (inferior_sos)
|
911 |
|
|
{
|
912 |
|
|
/* Connected to a running target. Update our shared library table. */
|
913 |
|
|
solib_add (NULL, 0, NULL, auto_solib_add);
|
914 |
|
|
}
|
915 |
|
|
while (inferior_sos)
|
916 |
|
|
{
|
917 |
|
|
if (strcmp (buf, inferior_sos->so_original_name) == 0)
|
918 |
|
|
{
|
919 |
|
|
load_addr_found = 1;
|
920 |
|
|
load_addr = LM_ADDR (inferior_sos);
|
921 |
|
|
break;
|
922 |
|
|
}
|
923 |
|
|
inferior_sos = inferior_sos->next;
|
924 |
|
|
}
|
925 |
|
|
|
926 |
|
|
/* Otherwise we find the dynamic linker's base address by examining
|
927 |
|
|
the current pc (which should point at the entry point for the
|
928 |
|
|
dynamic linker) and subtracting the offset of the entry point. */
|
929 |
|
|
if (!load_addr_found)
|
930 |
|
|
load_addr = read_pc () - tmp_bfd->start_address;
|
931 |
|
|
|
932 |
|
|
/* Record the relocated start and end address of the dynamic linker
|
933 |
|
|
text and plt section for svr4_in_dynsym_resolve_code. */
|
934 |
|
|
interp_sect = bfd_get_section_by_name (tmp_bfd, ".text");
|
935 |
|
|
if (interp_sect)
|
936 |
|
|
{
|
937 |
|
|
interp_text_sect_low =
|
938 |
|
|
bfd_section_vma (tmp_bfd, interp_sect) + load_addr;
|
939 |
|
|
interp_text_sect_high =
|
940 |
|
|
interp_text_sect_low + bfd_section_size (tmp_bfd, interp_sect);
|
941 |
|
|
}
|
942 |
|
|
interp_sect = bfd_get_section_by_name (tmp_bfd, ".plt");
|
943 |
|
|
if (interp_sect)
|
944 |
|
|
{
|
945 |
|
|
interp_plt_sect_low =
|
946 |
|
|
bfd_section_vma (tmp_bfd, interp_sect) + load_addr;
|
947 |
|
|
interp_plt_sect_high =
|
948 |
|
|
interp_plt_sect_low + bfd_section_size (tmp_bfd, interp_sect);
|
949 |
|
|
}
|
950 |
|
|
|
951 |
|
|
/* Now try to set a breakpoint in the dynamic linker. */
|
952 |
|
|
for (bkpt_namep = solib_break_names; *bkpt_namep != NULL; bkpt_namep++)
|
953 |
|
|
{
|
954 |
|
|
sym_addr = bfd_lookup_symbol (tmp_bfd, *bkpt_namep);
|
955 |
|
|
if (sym_addr != 0)
|
956 |
|
|
break;
|
957 |
|
|
}
|
958 |
|
|
|
959 |
|
|
/* We're done with the temporary bfd. */
|
960 |
|
|
bfd_close (tmp_bfd);
|
961 |
|
|
|
962 |
|
|
if (sym_addr != 0)
|
963 |
|
|
{
|
964 |
|
|
create_solib_event_breakpoint (load_addr + sym_addr);
|
965 |
|
|
return 1;
|
966 |
|
|
}
|
967 |
|
|
|
968 |
|
|
/* For whatever reason we couldn't set a breakpoint in the dynamic
|
969 |
|
|
linker. Warn and drop into the old code. */
|
970 |
|
|
bkpt_at_symbol:
|
971 |
|
|
warning ("Unable to find dynamic linker breakpoint function.\nGDB will be unable to debug shared library initializers\nand track explicitly loaded dynamic code.");
|
972 |
|
|
}
|
973 |
|
|
|
974 |
|
|
/* Scan through the list of symbols, trying to look up the symbol and
|
975 |
|
|
set a breakpoint there. Terminate loop when we/if we succeed. */
|
976 |
|
|
|
977 |
|
|
breakpoint_addr = 0;
|
978 |
|
|
for (bkpt_namep = bkpt_names; *bkpt_namep != NULL; bkpt_namep++)
|
979 |
|
|
{
|
980 |
|
|
msymbol = lookup_minimal_symbol (*bkpt_namep, NULL, symfile_objfile);
|
981 |
|
|
if ((msymbol != NULL) && (SYMBOL_VALUE_ADDRESS (msymbol) != 0))
|
982 |
|
|
{
|
983 |
|
|
create_solib_event_breakpoint (SYMBOL_VALUE_ADDRESS (msymbol));
|
984 |
|
|
return 1;
|
985 |
|
|
}
|
986 |
|
|
}
|
987 |
|
|
|
988 |
|
|
/* Nothing good happened. */
|
989 |
|
|
success = 0;
|
990 |
|
|
|
991 |
|
|
#endif /* BKPT_AT_SYMBOL */
|
992 |
|
|
|
993 |
|
|
return (success);
|
994 |
|
|
}
|
995 |
|
|
|
996 |
|
|
/*
|
997 |
|
|
|
998 |
|
|
LOCAL FUNCTION
|
999 |
|
|
|
1000 |
|
|
special_symbol_handling -- additional shared library symbol handling
|
1001 |
|
|
|
1002 |
|
|
SYNOPSIS
|
1003 |
|
|
|
1004 |
|
|
void special_symbol_handling ()
|
1005 |
|
|
|
1006 |
|
|
DESCRIPTION
|
1007 |
|
|
|
1008 |
|
|
Once the symbols from a shared object have been loaded in the usual
|
1009 |
|
|
way, we are called to do any system specific symbol handling that
|
1010 |
|
|
is needed.
|
1011 |
|
|
|
1012 |
|
|
For SunOS4, this consisted of grunging around in the dynamic
|
1013 |
|
|
linkers structures to find symbol definitions for "common" symbols
|
1014 |
|
|
and adding them to the minimal symbol table for the runtime common
|
1015 |
|
|
objfile.
|
1016 |
|
|
|
1017 |
|
|
However, for SVR4, there's nothing to do.
|
1018 |
|
|
|
1019 |
|
|
*/
|
1020 |
|
|
|
1021 |
|
|
static void
|
1022 |
|
|
svr4_special_symbol_handling (void)
|
1023 |
|
|
{
|
1024 |
|
|
}
|
1025 |
|
|
|
1026 |
|
|
/* Relocate the main executable. This function should be called upon
|
1027 |
|
|
stopping the inferior process at the entry point to the program.
|
1028 |
|
|
The entry point from BFD is compared to the PC and if they are
|
1029 |
|
|
different, the main executable is relocated by the proper amount.
|
1030 |
|
|
|
1031 |
|
|
As written it will only attempt to relocate executables which
|
1032 |
|
|
lack interpreter sections. It seems likely that only dynamic
|
1033 |
|
|
linker executables will get relocated, though it should work
|
1034 |
|
|
properly for a position-independent static executable as well. */
|
1035 |
|
|
|
1036 |
|
|
static void
|
1037 |
|
|
svr4_relocate_main_executable (void)
|
1038 |
|
|
{
|
1039 |
|
|
asection *interp_sect;
|
1040 |
|
|
CORE_ADDR pc = read_pc ();
|
1041 |
|
|
|
1042 |
|
|
/* Decide if the objfile needs to be relocated. As indicated above,
|
1043 |
|
|
we will only be here when execution is stopped at the beginning
|
1044 |
|
|
of the program. Relocation is necessary if the address at which
|
1045 |
|
|
we are presently stopped differs from the start address stored in
|
1046 |
|
|
the executable AND there's no interpreter section. The condition
|
1047 |
|
|
regarding the interpreter section is very important because if
|
1048 |
|
|
there *is* an interpreter section, execution will begin there
|
1049 |
|
|
instead. When there is an interpreter section, the start address
|
1050 |
|
|
is (presumably) used by the interpreter at some point to start
|
1051 |
|
|
execution of the program.
|
1052 |
|
|
|
1053 |
|
|
If there is an interpreter, it is normal for it to be set to an
|
1054 |
|
|
arbitrary address at the outset. The job of finding it is
|
1055 |
|
|
handled in enable_break().
|
1056 |
|
|
|
1057 |
|
|
So, to summarize, relocations are necessary when there is no
|
1058 |
|
|
interpreter section and the start address obtained from the
|
1059 |
|
|
executable is different from the address at which GDB is
|
1060 |
|
|
currently stopped.
|
1061 |
|
|
|
1062 |
|
|
[ The astute reader will note that we also test to make sure that
|
1063 |
|
|
the executable in question has the DYNAMIC flag set. It is my
|
1064 |
|
|
opinion that this test is unnecessary (undesirable even). It
|
1065 |
|
|
was added to avoid inadvertent relocation of an executable
|
1066 |
|
|
whose e_type member in the ELF header is not ET_DYN. There may
|
1067 |
|
|
be a time in the future when it is desirable to do relocations
|
1068 |
|
|
on other types of files as well in which case this condition
|
1069 |
|
|
should either be removed or modified to accomodate the new file
|
1070 |
|
|
type. (E.g, an ET_EXEC executable which has been built to be
|
1071 |
|
|
position-independent could safely be relocated by the OS if
|
1072 |
|
|
desired. It is true that this violates the ABI, but the ABI
|
1073 |
|
|
has been known to be bent from time to time.) - Kevin, Nov 2000. ]
|
1074 |
|
|
*/
|
1075 |
|
|
|
1076 |
|
|
interp_sect = bfd_get_section_by_name (exec_bfd, ".interp");
|
1077 |
|
|
if (interp_sect == NULL
|
1078 |
|
|
&& (bfd_get_file_flags (exec_bfd) & DYNAMIC) != 0
|
1079 |
|
|
&& bfd_get_start_address (exec_bfd) != pc)
|
1080 |
|
|
{
|
1081 |
|
|
struct cleanup *old_chain;
|
1082 |
|
|
struct section_offsets *new_offsets;
|
1083 |
|
|
int i, changed;
|
1084 |
|
|
CORE_ADDR displacement;
|
1085 |
|
|
|
1086 |
|
|
/* It is necessary to relocate the objfile. The amount to
|
1087 |
|
|
relocate by is simply the address at which we are stopped
|
1088 |
|
|
minus the starting address from the executable.
|
1089 |
|
|
|
1090 |
|
|
We relocate all of the sections by the same amount. This
|
1091 |
|
|
behavior is mandated by recent editions of the System V ABI.
|
1092 |
|
|
According to the System V Application Binary Interface,
|
1093 |
|
|
Edition 4.1, page 5-5:
|
1094 |
|
|
|
1095 |
|
|
... Though the system chooses virtual addresses for
|
1096 |
|
|
individual processes, it maintains the segments' relative
|
1097 |
|
|
positions. Because position-independent code uses relative
|
1098 |
|
|
addressesing between segments, the difference between
|
1099 |
|
|
virtual addresses in memory must match the difference
|
1100 |
|
|
between virtual addresses in the file. The difference
|
1101 |
|
|
between the virtual address of any segment in memory and
|
1102 |
|
|
the corresponding virtual address in the file is thus a
|
1103 |
|
|
single constant value for any one executable or shared
|
1104 |
|
|
object in a given process. This difference is the base
|
1105 |
|
|
address. One use of the base address is to relocate the
|
1106 |
|
|
memory image of the program during dynamic linking.
|
1107 |
|
|
|
1108 |
|
|
The same language also appears in Edition 4.0 of the System V
|
1109 |
|
|
ABI and is left unspecified in some of the earlier editions. */
|
1110 |
|
|
|
1111 |
|
|
displacement = pc - bfd_get_start_address (exec_bfd);
|
1112 |
|
|
changed = 0;
|
1113 |
|
|
|
1114 |
|
|
new_offsets = xcalloc (symfile_objfile->num_sections,
|
1115 |
|
|
sizeof (struct section_offsets));
|
1116 |
|
|
old_chain = make_cleanup (xfree, new_offsets);
|
1117 |
|
|
|
1118 |
|
|
for (i = 0; i < symfile_objfile->num_sections; i++)
|
1119 |
|
|
{
|
1120 |
|
|
if (displacement != ANOFFSET (symfile_objfile->section_offsets, i))
|
1121 |
|
|
changed = 1;
|
1122 |
|
|
new_offsets->offsets[i] = displacement;
|
1123 |
|
|
}
|
1124 |
|
|
|
1125 |
|
|
if (changed)
|
1126 |
|
|
objfile_relocate (symfile_objfile, new_offsets);
|
1127 |
|
|
|
1128 |
|
|
do_cleanups (old_chain);
|
1129 |
|
|
}
|
1130 |
|
|
}
|
1131 |
|
|
|
1132 |
|
|
/*
|
1133 |
|
|
|
1134 |
|
|
GLOBAL FUNCTION
|
1135 |
|
|
|
1136 |
|
|
svr4_solib_create_inferior_hook -- shared library startup support
|
1137 |
|
|
|
1138 |
|
|
SYNOPSIS
|
1139 |
|
|
|
1140 |
|
|
void svr4_solib_create_inferior_hook()
|
1141 |
|
|
|
1142 |
|
|
DESCRIPTION
|
1143 |
|
|
|
1144 |
|
|
When gdb starts up the inferior, it nurses it along (through the
|
1145 |
|
|
shell) until it is ready to execute it's first instruction. At this
|
1146 |
|
|
point, this function gets called via expansion of the macro
|
1147 |
|
|
SOLIB_CREATE_INFERIOR_HOOK.
|
1148 |
|
|
|
1149 |
|
|
For SunOS executables, this first instruction is typically the
|
1150 |
|
|
one at "_start", or a similar text label, regardless of whether
|
1151 |
|
|
the executable is statically or dynamically linked. The runtime
|
1152 |
|
|
startup code takes care of dynamically linking in any shared
|
1153 |
|
|
libraries, once gdb allows the inferior to continue.
|
1154 |
|
|
|
1155 |
|
|
For SVR4 executables, this first instruction is either the first
|
1156 |
|
|
instruction in the dynamic linker (for dynamically linked
|
1157 |
|
|
executables) or the instruction at "start" for statically linked
|
1158 |
|
|
executables. For dynamically linked executables, the system
|
1159 |
|
|
first exec's /lib/libc.so.N, which contains the dynamic linker,
|
1160 |
|
|
and starts it running. The dynamic linker maps in any needed
|
1161 |
|
|
shared libraries, maps in the actual user executable, and then
|
1162 |
|
|
jumps to "start" in the user executable.
|
1163 |
|
|
|
1164 |
|
|
For both SunOS shared libraries, and SVR4 shared libraries, we
|
1165 |
|
|
can arrange to cooperate with the dynamic linker to discover the
|
1166 |
|
|
names of shared libraries that are dynamically linked, and the
|
1167 |
|
|
base addresses to which they are linked.
|
1168 |
|
|
|
1169 |
|
|
This function is responsible for discovering those names and
|
1170 |
|
|
addresses, and saving sufficient information about them to allow
|
1171 |
|
|
their symbols to be read at a later time.
|
1172 |
|
|
|
1173 |
|
|
FIXME
|
1174 |
|
|
|
1175 |
|
|
Between enable_break() and disable_break(), this code does not
|
1176 |
|
|
properly handle hitting breakpoints which the user might have
|
1177 |
|
|
set in the startup code or in the dynamic linker itself. Proper
|
1178 |
|
|
handling will probably have to wait until the implementation is
|
1179 |
|
|
changed to use the "breakpoint handler function" method.
|
1180 |
|
|
|
1181 |
|
|
Also, what if child has exit()ed? Must exit loop somehow.
|
1182 |
|
|
*/
|
1183 |
|
|
|
1184 |
|
|
static void
|
1185 |
|
|
svr4_solib_create_inferior_hook (void)
|
1186 |
|
|
{
|
1187 |
|
|
/* Relocate the main executable if necessary. */
|
1188 |
|
|
svr4_relocate_main_executable ();
|
1189 |
|
|
|
1190 |
|
|
if (!enable_break ())
|
1191 |
|
|
{
|
1192 |
|
|
warning ("shared library handler failed to enable breakpoint");
|
1193 |
|
|
return;
|
1194 |
|
|
}
|
1195 |
|
|
|
1196 |
|
|
#if defined(_SCO_DS)
|
1197 |
|
|
/* SCO needs the loop below, other systems should be using the
|
1198 |
|
|
special shared library breakpoints and the shared library breakpoint
|
1199 |
|
|
service routine.
|
1200 |
|
|
|
1201 |
|
|
Now run the target. It will eventually hit the breakpoint, at
|
1202 |
|
|
which point all of the libraries will have been mapped in and we
|
1203 |
|
|
can go groveling around in the dynamic linker structures to find
|
1204 |
|
|
out what we need to know about them. */
|
1205 |
|
|
|
1206 |
|
|
clear_proceed_status ();
|
1207 |
|
|
stop_soon_quietly = 1;
|
1208 |
|
|
stop_signal = TARGET_SIGNAL_0;
|
1209 |
|
|
do
|
1210 |
|
|
{
|
1211 |
|
|
target_resume (pid_to_ptid (-1), 0, stop_signal);
|
1212 |
|
|
wait_for_inferior ();
|
1213 |
|
|
}
|
1214 |
|
|
while (stop_signal != TARGET_SIGNAL_TRAP);
|
1215 |
|
|
stop_soon_quietly = 0;
|
1216 |
|
|
#endif /* defined(_SCO_DS) */
|
1217 |
|
|
}
|
1218 |
|
|
|
1219 |
|
|
static void
|
1220 |
|
|
svr4_clear_solib (void)
|
1221 |
|
|
{
|
1222 |
|
|
debug_base = 0;
|
1223 |
|
|
}
|
1224 |
|
|
|
1225 |
|
|
static void
|
1226 |
|
|
svr4_free_so (struct so_list *so)
|
1227 |
|
|
{
|
1228 |
|
|
xfree (so->lm_info->lm);
|
1229 |
|
|
xfree (so->lm_info);
|
1230 |
|
|
}
|
1231 |
|
|
|
1232 |
|
|
|
1233 |
|
|
/* Clear any bits of ADDR that wouldn't fit in a target-format
|
1234 |
|
|
data pointer. "Data pointer" here refers to whatever sort of
|
1235 |
|
|
address the dynamic linker uses to manage its sections. At the
|
1236 |
|
|
moment, we don't support shared libraries on any processors where
|
1237 |
|
|
code and data pointers are different sizes.
|
1238 |
|
|
|
1239 |
|
|
This isn't really the right solution. What we really need here is
|
1240 |
|
|
a way to do arithmetic on CORE_ADDR values that respects the
|
1241 |
|
|
natural pointer/address correspondence. (For example, on the MIPS,
|
1242 |
|
|
converting a 32-bit pointer to a 64-bit CORE_ADDR requires you to
|
1243 |
|
|
sign-extend the value. There, simply truncating the bits above
|
1244 |
|
|
TARGET_PTR_BIT, as we do below, is no good.) This should probably
|
1245 |
|
|
be a new gdbarch method or something. */
|
1246 |
|
|
static CORE_ADDR
|
1247 |
|
|
svr4_truncate_ptr (CORE_ADDR addr)
|
1248 |
|
|
{
|
1249 |
|
|
if (TARGET_PTR_BIT == sizeof (CORE_ADDR) * 8)
|
1250 |
|
|
/* We don't need to truncate anything, and the bit twiddling below
|
1251 |
|
|
will fail due to overflow problems. */
|
1252 |
|
|
return addr;
|
1253 |
|
|
else
|
1254 |
|
|
return addr & (((CORE_ADDR) 1 << TARGET_PTR_BIT) - 1);
|
1255 |
|
|
}
|
1256 |
|
|
|
1257 |
|
|
|
1258 |
|
|
static void
|
1259 |
|
|
svr4_relocate_section_addresses (struct so_list *so,
|
1260 |
|
|
struct section_table *sec)
|
1261 |
|
|
{
|
1262 |
|
|
sec->addr = svr4_truncate_ptr (sec->addr + LM_ADDR (so));
|
1263 |
|
|
sec->endaddr = svr4_truncate_ptr (sec->endaddr + LM_ADDR (so));
|
1264 |
|
|
}
|
1265 |
|
|
|
1266 |
|
|
|
1267 |
|
|
/* Fetch a link_map_offsets structure for native targets using struct
|
1268 |
|
|
definitions from link.h. See solib-legacy.c for the function
|
1269 |
|
|
which does the actual work.
|
1270 |
|
|
|
1271 |
|
|
Note: For non-native targets (i.e. cross-debugging situations),
|
1272 |
|
|
a target specific fetch_link_map_offsets() function should be
|
1273 |
|
|
defined and registered via set_solib_svr4_fetch_link_map_offsets(). */
|
1274 |
|
|
|
1275 |
|
|
static struct link_map_offsets *
|
1276 |
|
|
legacy_fetch_link_map_offsets (void)
|
1277 |
|
|
{
|
1278 |
|
|
if (legacy_svr4_fetch_link_map_offsets_hook)
|
1279 |
|
|
return legacy_svr4_fetch_link_map_offsets_hook ();
|
1280 |
|
|
else
|
1281 |
|
|
{
|
1282 |
|
|
internal_error (__FILE__, __LINE__,
|
1283 |
|
|
"legacy_fetch_link_map_offsets called without legacy "
|
1284 |
|
|
"link_map support enabled.");
|
1285 |
|
|
return 0;
|
1286 |
|
|
}
|
1287 |
|
|
}
|
1288 |
|
|
|
1289 |
|
|
/* Fetch a link_map_offsets structure using the method registered in the
|
1290 |
|
|
architecture vector. */
|
1291 |
|
|
|
1292 |
|
|
static struct link_map_offsets *
|
1293 |
|
|
svr4_fetch_link_map_offsets (void)
|
1294 |
|
|
{
|
1295 |
|
|
struct link_map_offsets *(*flmo)(void) =
|
1296 |
|
|
gdbarch_data (current_gdbarch, fetch_link_map_offsets_gdbarch_data);
|
1297 |
|
|
|
1298 |
|
|
if (flmo == NULL)
|
1299 |
|
|
{
|
1300 |
|
|
internal_error (__FILE__, __LINE__,
|
1301 |
|
|
"svr4_fetch_link_map_offsets: fetch_link_map_offsets "
|
1302 |
|
|
"method not defined for this architecture.");
|
1303 |
|
|
return 0;
|
1304 |
|
|
}
|
1305 |
|
|
else
|
1306 |
|
|
return (flmo ());
|
1307 |
|
|
}
|
1308 |
|
|
|
1309 |
|
|
/* set_solib_svr4_fetch_link_map_offsets() is intended to be called by
|
1310 |
|
|
a <arch>_gdbarch_init() function. It is used to establish an
|
1311 |
|
|
architecture specific link_map_offsets fetcher for the architecture
|
1312 |
|
|
being defined. */
|
1313 |
|
|
|
1314 |
|
|
void
|
1315 |
|
|
set_solib_svr4_fetch_link_map_offsets (struct gdbarch *gdbarch,
|
1316 |
|
|
struct link_map_offsets *(*flmo) (void))
|
1317 |
|
|
{
|
1318 |
|
|
set_gdbarch_data (gdbarch, fetch_link_map_offsets_gdbarch_data, flmo);
|
1319 |
|
|
}
|
1320 |
|
|
|
1321 |
|
|
/* Initialize the architecture-specific link_map_offsets fetcher.
|
1322 |
|
|
This is called after <arch>_gdbarch_init() has set up its `struct
|
1323 |
|
|
gdbarch' for the new architecture, and is only called if the
|
1324 |
|
|
link_map_offsets fetcher isn't already initialized (which is
|
1325 |
|
|
usually done by calling set_solib_svr4_fetch_link_map_offsets()
|
1326 |
|
|
above in <arch>_gdbarch_init()). Therefore we attempt to provide a
|
1327 |
|
|
reasonable alternative (for native targets anyway) if the
|
1328 |
|
|
<arch>_gdbarch_init() fails to call
|
1329 |
|
|
set_solib_svr4_fetch_link_map_offsets(). */
|
1330 |
|
|
|
1331 |
|
|
static void *
|
1332 |
|
|
init_fetch_link_map_offsets (struct gdbarch *gdbarch)
|
1333 |
|
|
{
|
1334 |
|
|
return legacy_fetch_link_map_offsets;
|
1335 |
|
|
}
|
1336 |
|
|
|
1337 |
|
|
static struct target_so_ops svr4_so_ops;
|
1338 |
|
|
|
1339 |
|
|
void
|
1340 |
|
|
_initialize_svr4_solib (void)
|
1341 |
|
|
{
|
1342 |
|
|
fetch_link_map_offsets_gdbarch_data =
|
1343 |
|
|
register_gdbarch_data (init_fetch_link_map_offsets, 0);
|
1344 |
|
|
|
1345 |
|
|
svr4_so_ops.relocate_section_addresses = svr4_relocate_section_addresses;
|
1346 |
|
|
svr4_so_ops.free_so = svr4_free_so;
|
1347 |
|
|
svr4_so_ops.clear_solib = svr4_clear_solib;
|
1348 |
|
|
svr4_so_ops.solib_create_inferior_hook = svr4_solib_create_inferior_hook;
|
1349 |
|
|
svr4_so_ops.special_symbol_handling = svr4_special_symbol_handling;
|
1350 |
|
|
svr4_so_ops.current_sos = svr4_current_sos;
|
1351 |
|
|
svr4_so_ops.open_symbol_file_object = open_symbol_file_object;
|
1352 |
|
|
svr4_so_ops.in_dynsym_resolve_code = svr4_in_dynsym_resolve_code;
|
1353 |
|
|
|
1354 |
|
|
/* FIXME: Don't do this here. *_gdbarch_init() should set so_ops. */
|
1355 |
|
|
current_target_so_ops = &svr4_so_ops;
|
1356 |
|
|
}
|