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7e3cb44ccb
set_solib_ops to install SVR4 operations. (_initialize_svr4_solib): Do not set current_target_so_ops. * config/i386/i386gnu.mh (NATDEPFILES): Move solib.o, solib-svr4.o ... * config/i386/i386gnu.mt (TDEPFILES): ... to here.
1589 lines
49 KiB
C
1589 lines
49 KiB
C
/* Handle SVR4 shared libraries for GDB, the GNU Debugger.
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Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000,
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2001, 2003, 2004, 2005, 2006, 2007 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 3 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, see <http://www.gnu.org/licenses/>. */
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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 "gdb_assert.h"
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#include "solist.h"
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#include "solib.h"
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#include "solib-svr4.h"
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#include "bfd-target.h"
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#include "elf-bfd.h"
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#include "exec.h"
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#include "auxv.h"
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static struct link_map_offsets *svr4_fetch_link_map_offsets (void);
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static int svr4_have_link_map_offsets (void);
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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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gdb_byte *lm;
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/* Amount by which addresses in the binary should be relocated to
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match the inferior. This could most often be taken directly
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from lm, but when prelinking is involved and the prelink base
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address changes, we may need a different offset, we want to
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warn about the difference and compute it only once. */
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CORE_ADDR l_addr;
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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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/* link map access functions */
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static CORE_ADDR
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LM_ADDR_FROM_LINK_MAP (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_typed_address (so->lm_info->lm + lmo->l_addr_offset,
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builtin_type_void_data_ptr);
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}
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static int
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HAS_LM_DYNAMIC_FROM_LINK_MAP ()
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{
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struct link_map_offsets *lmo = svr4_fetch_link_map_offsets ();
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return lmo->l_ld_offset >= 0;
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}
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static CORE_ADDR
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LM_DYNAMIC_FROM_LINK_MAP (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_typed_address (so->lm_info->lm + lmo->l_ld_offset,
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builtin_type_void_data_ptr);
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}
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static CORE_ADDR
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LM_ADDR_CHECK (struct so_list *so, bfd *abfd)
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{
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if (so->lm_info->l_addr == (CORE_ADDR)-1)
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{
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struct bfd_section *dyninfo_sect;
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CORE_ADDR l_addr, l_dynaddr, dynaddr, align = 0x1000;
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l_addr = LM_ADDR_FROM_LINK_MAP (so);
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if (! abfd || ! HAS_LM_DYNAMIC_FROM_LINK_MAP ())
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goto set_addr;
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l_dynaddr = LM_DYNAMIC_FROM_LINK_MAP (so);
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dyninfo_sect = bfd_get_section_by_name (abfd, ".dynamic");
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if (dyninfo_sect == NULL)
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goto set_addr;
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dynaddr = bfd_section_vma (abfd, dyninfo_sect);
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if (dynaddr + l_addr != l_dynaddr)
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{
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if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
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{
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Elf_Internal_Ehdr *ehdr = elf_tdata (abfd)->elf_header;
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Elf_Internal_Phdr *phdr = elf_tdata (abfd)->phdr;
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int i;
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align = 1;
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for (i = 0; i < ehdr->e_phnum; i++)
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if (phdr[i].p_type == PT_LOAD && phdr[i].p_align > align)
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align = phdr[i].p_align;
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}
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/* Turn it into a mask. */
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align--;
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/* If the changes match the alignment requirements, we
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assume we're using a core file that was generated by the
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same binary, just prelinked with a different base offset.
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If it doesn't match, we may have a different binary, the
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same binary with the dynamic table loaded at an unrelated
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location, or anything, really. To avoid regressions,
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don't adjust the base offset in the latter case, although
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odds are that, if things really changed, debugging won't
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quite work. */
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if ((l_addr & align) == ((l_dynaddr - dynaddr) & align))
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{
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l_addr = l_dynaddr - dynaddr;
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warning (_(".dynamic section for \"%s\" "
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"is not at the expected address"), so->so_name);
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warning (_("difference appears to be caused by prelink, "
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"adjusting expectations"));
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}
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else
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warning (_(".dynamic section for \"%s\" "
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"is not at the expected address "
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"(wrong library or version mismatch?)"), so->so_name);
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}
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set_addr:
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so->lm_info->l_addr = l_addr;
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}
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return so->lm_info->l_addr;
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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_typed_address (so->lm_info->lm + lmo->l_next_offset,
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builtin_type_void_data_ptr);
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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_typed_address (so->lm_info->lm + lmo->l_name_offset,
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builtin_type_void_data_ptr);
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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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/* Assume that everything is a library if the dynamic loader was loaded
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late by a static executable. */
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if (bfd_get_section_by_name (exec_bfd, ".dynamic") == NULL)
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return 0;
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return extract_typed_address (so->lm_info->lm + lmo->l_prev_offset,
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builtin_type_void_data_ptr) == 0;
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}
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static CORE_ADDR debug_base; /* Base of dynamic linker structures */
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/* Validity flag for debug_loader_offset. */
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static int debug_loader_offset_p;
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/* Load address for the dynamic linker, inferred. */
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static CORE_ADDR debug_loader_offset;
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/* Name of the dynamic linker, valid if debug_loader_offset_p. */
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static char *debug_loader_name;
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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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notification routine in the shared library.
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The returned symbol may be in a code or data section; functions
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will normally be in a code section, but may be in a data section
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if this architecture uses function descriptors.
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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, 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 (strcmp (sym->name, symname) == 0
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&& (sym->section->flags & (SEC_CODE | SEC_DATA)) != 0)
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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, 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 (strcmp (sym->name, symname) == 0
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&& (sym->section->flags & (SEC_CODE | SEC_DATA)) != 0)
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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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/* Scan for DYNTAG in .dynamic section of ABFD. If DYNTAG is found 1 is
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returned and the corresponding PTR is set. */
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static int
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scan_dyntag (int dyntag, bfd *abfd, CORE_ADDR *ptr)
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{
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int arch_size, step, sect_size;
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long dyn_tag;
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CORE_ADDR dyn_ptr, dyn_addr;
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gdb_byte *bufend, *bufstart, *buf;
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Elf32_External_Dyn *x_dynp_32;
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Elf64_External_Dyn *x_dynp_64;
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struct bfd_section *sect;
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if (abfd == NULL)
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return 0;
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arch_size = bfd_get_arch_size (abfd);
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if (arch_size == -1)
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return 0;
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/* Find the start address of the .dynamic section. */
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sect = bfd_get_section_by_name (abfd, ".dynamic");
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if (sect == NULL)
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return 0;
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dyn_addr = bfd_section_vma (abfd, sect);
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/* Read in .dynamic from the BFD. We will get the actual value
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from memory later. */
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sect_size = bfd_section_size (abfd, sect);
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buf = bufstart = alloca (sect_size);
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if (!bfd_get_section_contents (abfd, sect,
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buf, 0, sect_size))
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return 0;
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/* Iterate over BUF and scan for DYNTAG. If found, set PTR and return. */
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step = (arch_size == 32) ? sizeof (Elf32_External_Dyn)
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: sizeof (Elf64_External_Dyn);
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for (bufend = buf + sect_size;
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buf < bufend;
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buf += step)
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{
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if (arch_size == 32)
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{
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x_dynp_32 = (Elf32_External_Dyn *) buf;
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dyn_tag = bfd_h_get_32 (abfd, (bfd_byte *) x_dynp_32->d_tag);
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dyn_ptr = bfd_h_get_32 (abfd, (bfd_byte *) x_dynp_32->d_un.d_ptr);
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}
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else
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{
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x_dynp_64 = (Elf64_External_Dyn *) buf;
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dyn_tag = bfd_h_get_64 (abfd, (bfd_byte *) x_dynp_64->d_tag);
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dyn_ptr = bfd_h_get_64 (abfd, (bfd_byte *) x_dynp_64->d_un.d_ptr);
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}
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if (dyn_tag == DT_NULL)
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return 0;
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if (dyn_tag == dyntag)
|
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{
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/* If requested, try to read the runtime value of this .dynamic
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entry. */
|
||
if (ptr)
|
||
{
|
||
gdb_byte ptr_buf[8];
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CORE_ADDR ptr_addr;
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||
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ptr_addr = dyn_addr + (buf - bufstart) + arch_size / 8;
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||
if (target_read_memory (ptr_addr, ptr_buf, arch_size / 8) == 0)
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||
dyn_ptr = extract_typed_address (ptr_buf,
|
||
builtin_type_void_data_ptr);
|
||
*ptr = dyn_ptr;
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||
}
|
||
return 1;
|
||
}
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
|
||
/*
|
||
|
||
LOCAL FUNCTION
|
||
|
||
elf_locate_base -- locate the base address of dynamic linker structs
|
||
for SVR4 elf targets.
|
||
|
||
SYNOPSIS
|
||
|
||
CORE_ADDR elf_locate_base (void)
|
||
|
||
DESCRIPTION
|
||
|
||
For SVR4 elf targets the address of the dynamic linker's runtime
|
||
structure is contained within the dynamic info section in the
|
||
executable file. The dynamic section is also mapped into the
|
||
inferior address space. Because the runtime loader fills in the
|
||
real address before starting the inferior, we have to read in the
|
||
dynamic info section from the inferior address space.
|
||
If there are any errors while trying to find the address, we
|
||
silently return 0, otherwise the found address is returned.
|
||
|
||
*/
|
||
|
||
static CORE_ADDR
|
||
elf_locate_base (void)
|
||
{
|
||
struct minimal_symbol *msymbol;
|
||
CORE_ADDR dyn_ptr;
|
||
|
||
/* Look for DT_MIPS_RLD_MAP first. MIPS executables use this
|
||
instead of DT_DEBUG, although they sometimes contain an unused
|
||
DT_DEBUG. */
|
||
if (scan_dyntag (DT_MIPS_RLD_MAP, exec_bfd, &dyn_ptr))
|
||
{
|
||
gdb_byte *pbuf;
|
||
int pbuf_size = TYPE_LENGTH (builtin_type_void_data_ptr);
|
||
pbuf = alloca (pbuf_size);
|
||
/* DT_MIPS_RLD_MAP contains a pointer to the address
|
||
of the dynamic link structure. */
|
||
if (target_read_memory (dyn_ptr, pbuf, pbuf_size))
|
||
return 0;
|
||
return extract_typed_address (pbuf, builtin_type_void_data_ptr);
|
||
}
|
||
|
||
/* Find DT_DEBUG. */
|
||
if (scan_dyntag (DT_DEBUG, exec_bfd, &dyn_ptr))
|
||
return dyn_ptr;
|
||
|
||
/* This may be a static executable. Look for the symbol
|
||
conventionally named _r_debug, as a last resort. */
|
||
msymbol = lookup_minimal_symbol ("_r_debug", NULL, symfile_objfile);
|
||
if (msymbol != NULL)
|
||
return SYMBOL_VALUE_ADDRESS (msymbol);
|
||
|
||
/* DT_DEBUG entry not found. */
|
||
return 0;
|
||
}
|
||
|
||
/*
|
||
|
||
LOCAL FUNCTION
|
||
|
||
locate_base -- locate the base address of dynamic linker structs
|
||
|
||
SYNOPSIS
|
||
|
||
CORE_ADDR locate_base (void)
|
||
|
||
DESCRIPTION
|
||
|
||
For both the SunOS and SVR4 shared library implementations, if the
|
||
inferior executable has been linked dynamically, there is a single
|
||
address somewhere in the inferior's data space which is the key to
|
||
locating all of the dynamic linker's runtime structures. This
|
||
address is the value of the debug base symbol. The job of this
|
||
function is to find and return that address, or to return 0 if there
|
||
is no such address (the executable is statically linked for example).
|
||
|
||
For SunOS, the job is almost trivial, since the dynamic linker and
|
||
all of it's structures are statically linked to the executable at
|
||
link time. Thus the symbol for the address we are looking for has
|
||
already been added to the minimal symbol table for the executable's
|
||
objfile at the time the symbol file's symbols were read, and all we
|
||
have to do is look it up there. Note that we explicitly do NOT want
|
||
to find the copies in the shared library.
|
||
|
||
The SVR4 version is a bit more complicated because the address
|
||
is contained somewhere in the dynamic info section. We have to go
|
||
to a lot more work to discover the address of the debug base symbol.
|
||
Because of this complexity, we cache the value we find and return that
|
||
value on subsequent invocations. Note there is no copy in the
|
||
executable symbol tables.
|
||
|
||
*/
|
||
|
||
static CORE_ADDR
|
||
locate_base (void)
|
||
{
|
||
/* Check to see if we have a currently valid address, and if so, avoid
|
||
doing all this work again and just return the cached address. If
|
||
we have no cached address, try to locate it in the dynamic info
|
||
section for ELF executables. There's no point in doing any of this
|
||
though if we don't have some link map offsets to work with. */
|
||
|
||
if (debug_base == 0 && svr4_have_link_map_offsets ())
|
||
{
|
||
if (exec_bfd != NULL
|
||
&& bfd_get_flavour (exec_bfd) == bfd_target_elf_flavour)
|
||
debug_base = elf_locate_base ();
|
||
}
|
||
return (debug_base);
|
||
}
|
||
|
||
/* Find the first element in the inferior's dynamic link map, and
|
||
return its address in the inferior.
|
||
|
||
FIXME: Perhaps we should validate the info somehow, perhaps by
|
||
checking r_version for a known version number, or r_state for
|
||
RT_CONSISTENT. */
|
||
|
||
static CORE_ADDR
|
||
solib_svr4_r_map (void)
|
||
{
|
||
struct link_map_offsets *lmo = svr4_fetch_link_map_offsets ();
|
||
|
||
return read_memory_typed_address (debug_base + lmo->r_map_offset,
|
||
builtin_type_void_data_ptr);
|
||
}
|
||
|
||
/* Find the link map for the dynamic linker (if it is not in the
|
||
normal list of loaded shared objects). */
|
||
|
||
static CORE_ADDR
|
||
solib_svr4_r_ldsomap (void)
|
||
{
|
||
struct link_map_offsets *lmo = svr4_fetch_link_map_offsets ();
|
||
ULONGEST version;
|
||
|
||
/* Check version, and return zero if `struct r_debug' doesn't have
|
||
the r_ldsomap member. */
|
||
version = read_memory_unsigned_integer (debug_base + lmo->r_version_offset,
|
||
lmo->r_version_size);
|
||
if (version < 2 || lmo->r_ldsomap_offset == -1)
|
||
return 0;
|
||
|
||
return read_memory_typed_address (debug_base + lmo->r_ldsomap_offset,
|
||
builtin_type_void_data_ptr);
|
||
}
|
||
|
||
/*
|
||
|
||
LOCAL FUNCTION
|
||
|
||
open_symbol_file_object
|
||
|
||
SYNOPSIS
|
||
|
||
void open_symbol_file_object (void *from_tty)
|
||
|
||
DESCRIPTION
|
||
|
||
If no open symbol file, attempt to locate and open the main symbol
|
||
file. On SVR4 systems, this is the first link map entry. If its
|
||
name is here, we can open it. Useful when attaching to a process
|
||
without first loading its symbol file.
|
||
|
||
If FROM_TTYP dereferences to a non-zero integer, allow messages to
|
||
be printed. This parameter is a pointer rather than an int because
|
||
open_symbol_file_object() is called via catch_errors() and
|
||
catch_errors() requires a pointer argument. */
|
||
|
||
static int
|
||
open_symbol_file_object (void *from_ttyp)
|
||
{
|
||
CORE_ADDR lm, l_name;
|
||
char *filename;
|
||
int errcode;
|
||
int from_tty = *(int *)from_ttyp;
|
||
struct link_map_offsets *lmo = svr4_fetch_link_map_offsets ();
|
||
int l_name_size = TYPE_LENGTH (builtin_type_void_data_ptr);
|
||
gdb_byte *l_name_buf = xmalloc (l_name_size);
|
||
struct cleanup *cleanups = make_cleanup (xfree, l_name_buf);
|
||
|
||
if (symfile_objfile)
|
||
if (!query ("Attempt to reload symbols from process? "))
|
||
return 0;
|
||
|
||
if ((debug_base = locate_base ()) == 0)
|
||
return 0; /* failed somehow... */
|
||
|
||
/* First link map member should be the executable. */
|
||
lm = solib_svr4_r_map ();
|
||
if (lm == 0)
|
||
return 0; /* failed somehow... */
|
||
|
||
/* Read address of name from target memory to GDB. */
|
||
read_memory (lm + lmo->l_name_offset, l_name_buf, l_name_size);
|
||
|
||
/* Convert the address to host format. */
|
||
l_name = extract_typed_address (l_name_buf, builtin_type_void_data_ptr);
|
||
|
||
/* Free l_name_buf. */
|
||
do_cleanups (cleanups);
|
||
|
||
if (l_name == 0)
|
||
return 0; /* No filename. */
|
||
|
||
/* Now fetch the filename from target memory. */
|
||
target_read_string (l_name, &filename, SO_NAME_MAX_PATH_SIZE - 1, &errcode);
|
||
make_cleanup (xfree, filename);
|
||
|
||
if (errcode)
|
||
{
|
||
warning (_("failed to read exec filename from attached file: %s"),
|
||
safe_strerror (errcode));
|
||
return 0;
|
||
}
|
||
|
||
/* Have a pathname: read the symbol file. */
|
||
symbol_file_add_main (filename, from_tty);
|
||
|
||
return 1;
|
||
}
|
||
|
||
/* If no shared library information is available from the dynamic
|
||
linker, build a fallback list from other sources. */
|
||
|
||
static struct so_list *
|
||
svr4_default_sos (void)
|
||
{
|
||
struct so_list *head = NULL;
|
||
struct so_list **link_ptr = &head;
|
||
|
||
if (debug_loader_offset_p)
|
||
{
|
||
struct so_list *new = XZALLOC (struct so_list);
|
||
|
||
new->lm_info = xmalloc (sizeof (struct lm_info));
|
||
|
||
/* Nothing will ever check the cached copy of the link
|
||
map if we set l_addr. */
|
||
new->lm_info->l_addr = debug_loader_offset;
|
||
new->lm_info->lm = NULL;
|
||
|
||
strncpy (new->so_name, debug_loader_name, SO_NAME_MAX_PATH_SIZE - 1);
|
||
new->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0';
|
||
strcpy (new->so_original_name, new->so_name);
|
||
|
||
*link_ptr = new;
|
||
link_ptr = &new->next;
|
||
}
|
||
|
||
return head;
|
||
}
|
||
|
||
/* LOCAL FUNCTION
|
||
|
||
current_sos -- build a list of currently loaded shared objects
|
||
|
||
SYNOPSIS
|
||
|
||
struct so_list *current_sos ()
|
||
|
||
DESCRIPTION
|
||
|
||
Build a list of `struct so_list' objects describing the shared
|
||
objects currently loaded in the inferior. This list does not
|
||
include an entry for the main executable file.
|
||
|
||
Note that we only gather information directly available from the
|
||
inferior --- we don't examine any of the shared library files
|
||
themselves. The declaration of `struct so_list' says which fields
|
||
we provide values for. */
|
||
|
||
static struct so_list *
|
||
svr4_current_sos (void)
|
||
{
|
||
CORE_ADDR lm;
|
||
struct so_list *head = 0;
|
||
struct so_list **link_ptr = &head;
|
||
CORE_ADDR ldsomap = 0;
|
||
|
||
/* Make sure we've looked up the inferior's dynamic linker's base
|
||
structure. */
|
||
if (! debug_base)
|
||
{
|
||
debug_base = locate_base ();
|
||
|
||
/* If we can't find the dynamic linker's base structure, this
|
||
must not be a dynamically linked executable. Hmm. */
|
||
if (! debug_base)
|
||
return svr4_default_sos ();
|
||
}
|
||
|
||
/* Walk the inferior's link map list, and build our list of
|
||
`struct so_list' nodes. */
|
||
lm = solib_svr4_r_map ();
|
||
|
||
while (lm)
|
||
{
|
||
struct link_map_offsets *lmo = svr4_fetch_link_map_offsets ();
|
||
struct so_list *new = XZALLOC (struct so_list);
|
||
struct cleanup *old_chain = make_cleanup (xfree, new);
|
||
|
||
new->lm_info = xmalloc (sizeof (struct lm_info));
|
||
make_cleanup (xfree, new->lm_info);
|
||
|
||
new->lm_info->l_addr = (CORE_ADDR)-1;
|
||
new->lm_info->lm = xzalloc (lmo->link_map_size);
|
||
make_cleanup (xfree, new->lm_info->lm);
|
||
|
||
read_memory (lm, new->lm_info->lm, lmo->link_map_size);
|
||
|
||
lm = LM_NEXT (new);
|
||
|
||
/* For SVR4 versions, the first entry in the link map is for the
|
||
inferior executable, so we must ignore it. For some versions of
|
||
SVR4, it has no name. For others (Solaris 2.3 for example), it
|
||
does have a name, so we can no longer use a missing name to
|
||
decide when to ignore it. */
|
||
if (IGNORE_FIRST_LINK_MAP_ENTRY (new) && ldsomap == 0)
|
||
free_so (new);
|
||
else
|
||
{
|
||
int errcode;
|
||
char *buffer;
|
||
|
||
/* Extract this shared object's name. */
|
||
target_read_string (LM_NAME (new), &buffer,
|
||
SO_NAME_MAX_PATH_SIZE - 1, &errcode);
|
||
if (errcode != 0)
|
||
warning (_("Can't read pathname for load map: %s."),
|
||
safe_strerror (errcode));
|
||
else
|
||
{
|
||
strncpy (new->so_name, buffer, SO_NAME_MAX_PATH_SIZE - 1);
|
||
new->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0';
|
||
strcpy (new->so_original_name, new->so_name);
|
||
}
|
||
xfree (buffer);
|
||
|
||
/* If this entry has no name, or its name matches the name
|
||
for the main executable, don't include it in the list. */
|
||
if (! new->so_name[0]
|
||
|| match_main (new->so_name))
|
||
free_so (new);
|
||
else
|
||
{
|
||
new->next = 0;
|
||
*link_ptr = new;
|
||
link_ptr = &new->next;
|
||
}
|
||
}
|
||
|
||
/* On Solaris, the dynamic linker is not in the normal list of
|
||
shared objects, so make sure we pick it up too. Having
|
||
symbol information for the dynamic linker is quite crucial
|
||
for skipping dynamic linker resolver code. */
|
||
if (lm == 0 && ldsomap == 0)
|
||
lm = ldsomap = solib_svr4_r_ldsomap ();
|
||
|
||
discard_cleanups (old_chain);
|
||
}
|
||
|
||
if (head == NULL)
|
||
return svr4_default_sos ();
|
||
|
||
return head;
|
||
}
|
||
|
||
/* Get the address of the link_map for a given OBJFILE. Loop through
|
||
the link maps, and return the address of the one corresponding to
|
||
the given objfile. Note that this function takes into account that
|
||
objfile can be the main executable, not just a shared library. The
|
||
main executable has always an empty name field in the linkmap. */
|
||
|
||
CORE_ADDR
|
||
svr4_fetch_objfile_link_map (struct objfile *objfile)
|
||
{
|
||
CORE_ADDR lm;
|
||
|
||
if ((debug_base = locate_base ()) == 0)
|
||
return 0; /* failed somehow... */
|
||
|
||
/* Position ourselves on the first link map. */
|
||
lm = solib_svr4_r_map ();
|
||
while (lm)
|
||
{
|
||
/* Get info on the layout of the r_debug and link_map structures. */
|
||
struct link_map_offsets *lmo = svr4_fetch_link_map_offsets ();
|
||
int errcode;
|
||
char *buffer;
|
||
struct lm_info objfile_lm_info;
|
||
struct cleanup *old_chain;
|
||
CORE_ADDR name_address;
|
||
int l_name_size = TYPE_LENGTH (builtin_type_void_data_ptr);
|
||
gdb_byte *l_name_buf = xmalloc (l_name_size);
|
||
old_chain = make_cleanup (xfree, l_name_buf);
|
||
|
||
/* Set up the buffer to contain the portion of the link_map
|
||
structure that gdb cares about. Note that this is not the
|
||
whole link_map structure. */
|
||
objfile_lm_info.lm = xzalloc (lmo->link_map_size);
|
||
make_cleanup (xfree, objfile_lm_info.lm);
|
||
|
||
/* Read the link map into our internal structure. */
|
||
read_memory (lm, objfile_lm_info.lm, lmo->link_map_size);
|
||
|
||
/* Read address of name from target memory to GDB. */
|
||
read_memory (lm + lmo->l_name_offset, l_name_buf, l_name_size);
|
||
|
||
/* Extract this object's name. */
|
||
name_address = extract_typed_address (l_name_buf,
|
||
builtin_type_void_data_ptr);
|
||
target_read_string (name_address, &buffer,
|
||
SO_NAME_MAX_PATH_SIZE - 1, &errcode);
|
||
make_cleanup (xfree, buffer);
|
||
if (errcode != 0)
|
||
warning (_("Can't read pathname for load map: %s."),
|
||
safe_strerror (errcode));
|
||
else
|
||
{
|
||
/* Is this the linkmap for the file we want? */
|
||
/* If the file is not a shared library and has no name,
|
||
we are sure it is the main executable, so we return that. */
|
||
|
||
if (buffer
|
||
&& ((strcmp (buffer, objfile->name) == 0)
|
||
|| (!(objfile->flags & OBJF_SHARED)
|
||
&& (strcmp (buffer, "") == 0))))
|
||
{
|
||
do_cleanups (old_chain);
|
||
return lm;
|
||
}
|
||
}
|
||
/* Not the file we wanted, continue checking. */
|
||
lm = extract_typed_address (objfile_lm_info.lm + lmo->l_next_offset,
|
||
builtin_type_void_data_ptr);
|
||
do_cleanups (old_chain);
|
||
}
|
||
return 0;
|
||
}
|
||
|
||
/* On some systems, the only way to recognize the link map entry for
|
||
the main executable file is by looking at its name. Return
|
||
non-zero iff SONAME matches one of the known main executable names. */
|
||
|
||
static int
|
||
match_main (char *soname)
|
||
{
|
||
char **mainp;
|
||
|
||
for (mainp = main_name_list; *mainp != NULL; mainp++)
|
||
{
|
||
if (strcmp (soname, *mainp) == 0)
|
||
return (1);
|
||
}
|
||
|
||
return (0);
|
||
}
|
||
|
||
/* Return 1 if PC lies in the dynamic symbol resolution code of the
|
||
SVR4 run time loader. */
|
||
static CORE_ADDR interp_text_sect_low;
|
||
static CORE_ADDR interp_text_sect_high;
|
||
static CORE_ADDR interp_plt_sect_low;
|
||
static CORE_ADDR interp_plt_sect_high;
|
||
|
||
int
|
||
svr4_in_dynsym_resolve_code (CORE_ADDR pc)
|
||
{
|
||
return ((pc >= interp_text_sect_low && pc < interp_text_sect_high)
|
||
|| (pc >= interp_plt_sect_low && pc < interp_plt_sect_high)
|
||
|| in_plt_section (pc, NULL));
|
||
}
|
||
|
||
/* Given an executable's ABFD and target, compute the entry-point
|
||
address. */
|
||
|
||
static CORE_ADDR
|
||
exec_entry_point (struct bfd *abfd, struct target_ops *targ)
|
||
{
|
||
/* KevinB wrote ... for most targets, the address returned by
|
||
bfd_get_start_address() is the entry point for the start
|
||
function. But, for some targets, bfd_get_start_address() returns
|
||
the address of a function descriptor from which the entry point
|
||
address may be extracted. This address is extracted by
|
||
gdbarch_convert_from_func_ptr_addr(). The method
|
||
gdbarch_convert_from_func_ptr_addr() is the merely the identify
|
||
function for targets which don't use function descriptors. */
|
||
return gdbarch_convert_from_func_ptr_addr (current_gdbarch,
|
||
bfd_get_start_address (abfd),
|
||
targ);
|
||
}
|
||
|
||
/*
|
||
|
||
LOCAL FUNCTION
|
||
|
||
enable_break -- arrange for dynamic linker to hit breakpoint
|
||
|
||
SYNOPSIS
|
||
|
||
int enable_break (void)
|
||
|
||
DESCRIPTION
|
||
|
||
Both the SunOS and the SVR4 dynamic linkers have, as part of their
|
||
debugger interface, support for arranging for the inferior to hit
|
||
a breakpoint after mapping in the shared libraries. This function
|
||
enables that breakpoint.
|
||
|
||
For SunOS, there is a special flag location (in_debugger) which we
|
||
set to 1. When the dynamic linker sees this flag set, it will set
|
||
a breakpoint at a location known only to itself, after saving the
|
||
original contents of that place and the breakpoint address itself,
|
||
in it's own internal structures. When we resume the inferior, it
|
||
will eventually take a SIGTRAP when it runs into the breakpoint.
|
||
We handle this (in a different place) by restoring the contents of
|
||
the breakpointed location (which is only known after it stops),
|
||
chasing around to locate the shared libraries that have been
|
||
loaded, then resuming.
|
||
|
||
For SVR4, the debugger interface structure contains a member (r_brk)
|
||
which is statically initialized at the time the shared library is
|
||
built, to the offset of a function (_r_debug_state) which is guaran-
|
||
teed to be called once before mapping in a library, and again when
|
||
the mapping is complete. At the time we are examining this member,
|
||
it contains only the unrelocated offset of the function, so we have
|
||
to do our own relocation. Later, when the dynamic linker actually
|
||
runs, it relocates r_brk to be the actual address of _r_debug_state().
|
||
|
||
The debugger interface structure also contains an enumeration which
|
||
is set to either RT_ADD or RT_DELETE prior to changing the mapping,
|
||
depending upon whether or not the library is being mapped or unmapped,
|
||
and then set to RT_CONSISTENT after the library is mapped/unmapped.
|
||
*/
|
||
|
||
static int
|
||
enable_break (void)
|
||
{
|
||
#ifdef BKPT_AT_SYMBOL
|
||
|
||
struct minimal_symbol *msymbol;
|
||
char **bkpt_namep;
|
||
asection *interp_sect;
|
||
|
||
/* First, remove all the solib event breakpoints. Their addresses
|
||
may have changed since the last time we ran the program. */
|
||
remove_solib_event_breakpoints ();
|
||
|
||
interp_text_sect_low = interp_text_sect_high = 0;
|
||
interp_plt_sect_low = interp_plt_sect_high = 0;
|
||
|
||
/* Find the .interp section; if not found, warn the user and drop
|
||
into the old breakpoint at symbol code. */
|
||
interp_sect = bfd_get_section_by_name (exec_bfd, ".interp");
|
||
if (interp_sect)
|
||
{
|
||
unsigned int interp_sect_size;
|
||
char *buf;
|
||
CORE_ADDR load_addr = 0;
|
||
int load_addr_found = 0;
|
||
int loader_found_in_list = 0;
|
||
struct so_list *so;
|
||
bfd *tmp_bfd = NULL;
|
||
struct target_ops *tmp_bfd_target;
|
||
int tmp_fd = -1;
|
||
char *tmp_pathname = NULL;
|
||
CORE_ADDR sym_addr = 0;
|
||
|
||
/* Read the contents of the .interp section into a local buffer;
|
||
the contents specify the dynamic linker this program uses. */
|
||
interp_sect_size = bfd_section_size (exec_bfd, interp_sect);
|
||
buf = alloca (interp_sect_size);
|
||
bfd_get_section_contents (exec_bfd, interp_sect,
|
||
buf, 0, interp_sect_size);
|
||
|
||
/* Now we need to figure out where the dynamic linker was
|
||
loaded so that we can load its symbols and place a breakpoint
|
||
in the dynamic linker itself.
|
||
|
||
This address is stored on the stack. However, I've been unable
|
||
to find any magic formula to find it for Solaris (appears to
|
||
be trivial on GNU/Linux). Therefore, we have to try an alternate
|
||
mechanism to find the dynamic linker's base address. */
|
||
|
||
tmp_fd = solib_open (buf, &tmp_pathname);
|
||
if (tmp_fd >= 0)
|
||
tmp_bfd = bfd_fopen (tmp_pathname, gnutarget, FOPEN_RB, tmp_fd);
|
||
|
||
if (tmp_bfd == NULL)
|
||
goto bkpt_at_symbol;
|
||
|
||
/* Make sure the dynamic linker's really a useful object. */
|
||
if (!bfd_check_format (tmp_bfd, bfd_object))
|
||
{
|
||
warning (_("Unable to grok dynamic linker %s as an object file"), buf);
|
||
bfd_close (tmp_bfd);
|
||
goto bkpt_at_symbol;
|
||
}
|
||
|
||
/* Now convert the TMP_BFD into a target. That way target, as
|
||
well as BFD operations can be used. Note that closing the
|
||
target will also close the underlying bfd. */
|
||
tmp_bfd_target = target_bfd_reopen (tmp_bfd);
|
||
|
||
/* On a running target, we can get the dynamic linker's base
|
||
address from the shared library table. */
|
||
solib_add (NULL, 0, ¤t_target, auto_solib_add);
|
||
so = master_so_list ();
|
||
while (so)
|
||
{
|
||
if (strcmp (buf, so->so_original_name) == 0)
|
||
{
|
||
load_addr_found = 1;
|
||
loader_found_in_list = 1;
|
||
load_addr = LM_ADDR_CHECK (so, tmp_bfd);
|
||
break;
|
||
}
|
||
so = so->next;
|
||
}
|
||
|
||
/* If we were not able to find the base address of the loader
|
||
from our so_list, then try using the AT_BASE auxilliary entry. */
|
||
if (!load_addr_found)
|
||
if (target_auxv_search (¤t_target, AT_BASE, &load_addr) > 0)
|
||
load_addr_found = 1;
|
||
|
||
/* Otherwise we find the dynamic linker's base address by examining
|
||
the current pc (which should point at the entry point for the
|
||
dynamic linker) and subtracting the offset of the entry point.
|
||
|
||
This is more fragile than the previous approaches, but is a good
|
||
fallback method because it has actually been working well in
|
||
most cases. */
|
||
if (!load_addr_found)
|
||
load_addr = (read_pc ()
|
||
- exec_entry_point (tmp_bfd, tmp_bfd_target));
|
||
|
||
if (!loader_found_in_list)
|
||
{
|
||
debug_loader_name = xstrdup (buf);
|
||
debug_loader_offset_p = 1;
|
||
debug_loader_offset = load_addr;
|
||
solib_add (NULL, 0, ¤t_target, auto_solib_add);
|
||
}
|
||
|
||
/* Record the relocated start and end address of the dynamic linker
|
||
text and plt section for svr4_in_dynsym_resolve_code. */
|
||
interp_sect = bfd_get_section_by_name (tmp_bfd, ".text");
|
||
if (interp_sect)
|
||
{
|
||
interp_text_sect_low =
|
||
bfd_section_vma (tmp_bfd, interp_sect) + load_addr;
|
||
interp_text_sect_high =
|
||
interp_text_sect_low + bfd_section_size (tmp_bfd, interp_sect);
|
||
}
|
||
interp_sect = bfd_get_section_by_name (tmp_bfd, ".plt");
|
||
if (interp_sect)
|
||
{
|
||
interp_plt_sect_low =
|
||
bfd_section_vma (tmp_bfd, interp_sect) + load_addr;
|
||
interp_plt_sect_high =
|
||
interp_plt_sect_low + bfd_section_size (tmp_bfd, interp_sect);
|
||
}
|
||
|
||
/* Now try to set a breakpoint in the dynamic linker. */
|
||
for (bkpt_namep = solib_break_names; *bkpt_namep != NULL; bkpt_namep++)
|
||
{
|
||
sym_addr = bfd_lookup_symbol (tmp_bfd, *bkpt_namep);
|
||
if (sym_addr != 0)
|
||
break;
|
||
}
|
||
|
||
if (sym_addr != 0)
|
||
/* Convert 'sym_addr' from a function pointer to an address.
|
||
Because we pass tmp_bfd_target instead of the current
|
||
target, this will always produce an unrelocated value. */
|
||
sym_addr = gdbarch_convert_from_func_ptr_addr (current_gdbarch,
|
||
sym_addr,
|
||
tmp_bfd_target);
|
||
|
||
/* We're done with both the temporary bfd and target. Remember,
|
||
closing the target closes the underlying bfd. */
|
||
target_close (tmp_bfd_target, 0);
|
||
|
||
if (sym_addr != 0)
|
||
{
|
||
create_solib_event_breakpoint (load_addr + sym_addr);
|
||
return 1;
|
||
}
|
||
|
||
/* For whatever reason we couldn't set a breakpoint in the dynamic
|
||
linker. Warn and drop into the old code. */
|
||
bkpt_at_symbol:
|
||
xfree (tmp_pathname);
|
||
warning (_("Unable to find dynamic linker breakpoint function.\n"
|
||
"GDB will be unable to debug shared library initializers\n"
|
||
"and track explicitly loaded dynamic code."));
|
||
}
|
||
|
||
/* Scan through the lists of symbols, trying to look up the symbol and
|
||
set a breakpoint there. Terminate loop when we/if we succeed. */
|
||
|
||
for (bkpt_namep = solib_break_names; *bkpt_namep != NULL; bkpt_namep++)
|
||
{
|
||
msymbol = lookup_minimal_symbol (*bkpt_namep, NULL, symfile_objfile);
|
||
if ((msymbol != NULL) && (SYMBOL_VALUE_ADDRESS (msymbol) != 0))
|
||
{
|
||
create_solib_event_breakpoint (SYMBOL_VALUE_ADDRESS (msymbol));
|
||
return 1;
|
||
}
|
||
}
|
||
|
||
for (bkpt_namep = bkpt_names; *bkpt_namep != NULL; bkpt_namep++)
|
||
{
|
||
msymbol = lookup_minimal_symbol (*bkpt_namep, NULL, symfile_objfile);
|
||
if ((msymbol != NULL) && (SYMBOL_VALUE_ADDRESS (msymbol) != 0))
|
||
{
|
||
create_solib_event_breakpoint (SYMBOL_VALUE_ADDRESS (msymbol));
|
||
return 1;
|
||
}
|
||
}
|
||
#endif /* BKPT_AT_SYMBOL */
|
||
|
||
return 0;
|
||
}
|
||
|
||
/*
|
||
|
||
LOCAL FUNCTION
|
||
|
||
special_symbol_handling -- additional shared library symbol handling
|
||
|
||
SYNOPSIS
|
||
|
||
void special_symbol_handling ()
|
||
|
||
DESCRIPTION
|
||
|
||
Once the symbols from a shared object have been loaded in the usual
|
||
way, we are called to do any system specific symbol handling that
|
||
is needed.
|
||
|
||
For SunOS4, this consisted of grunging around in the dynamic
|
||
linkers structures to find symbol definitions for "common" symbols
|
||
and adding them to the minimal symbol table for the runtime common
|
||
objfile.
|
||
|
||
However, for SVR4, there's nothing to do.
|
||
|
||
*/
|
||
|
||
static void
|
||
svr4_special_symbol_handling (void)
|
||
{
|
||
}
|
||
|
||
/* Relocate the main executable. This function should be called upon
|
||
stopping the inferior process at the entry point to the program.
|
||
The entry point from BFD is compared to the PC and if they are
|
||
different, the main executable is relocated by the proper amount.
|
||
|
||
As written it will only attempt to relocate executables which
|
||
lack interpreter sections. It seems likely that only dynamic
|
||
linker executables will get relocated, though it should work
|
||
properly for a position-independent static executable as well. */
|
||
|
||
static void
|
||
svr4_relocate_main_executable (void)
|
||
{
|
||
asection *interp_sect;
|
||
CORE_ADDR pc = read_pc ();
|
||
|
||
/* Decide if the objfile needs to be relocated. As indicated above,
|
||
we will only be here when execution is stopped at the beginning
|
||
of the program. Relocation is necessary if the address at which
|
||
we are presently stopped differs from the start address stored in
|
||
the executable AND there's no interpreter section. The condition
|
||
regarding the interpreter section is very important because if
|
||
there *is* an interpreter section, execution will begin there
|
||
instead. When there is an interpreter section, the start address
|
||
is (presumably) used by the interpreter at some point to start
|
||
execution of the program.
|
||
|
||
If there is an interpreter, it is normal for it to be set to an
|
||
arbitrary address at the outset. The job of finding it is
|
||
handled in enable_break().
|
||
|
||
So, to summarize, relocations are necessary when there is no
|
||
interpreter section and the start address obtained from the
|
||
executable is different from the address at which GDB is
|
||
currently stopped.
|
||
|
||
[ The astute reader will note that we also test to make sure that
|
||
the executable in question has the DYNAMIC flag set. It is my
|
||
opinion that this test is unnecessary (undesirable even). It
|
||
was added to avoid inadvertent relocation of an executable
|
||
whose e_type member in the ELF header is not ET_DYN. There may
|
||
be a time in the future when it is desirable to do relocations
|
||
on other types of files as well in which case this condition
|
||
should either be removed or modified to accomodate the new file
|
||
type. (E.g, an ET_EXEC executable which has been built to be
|
||
position-independent could safely be relocated by the OS if
|
||
desired. It is true that this violates the ABI, but the ABI
|
||
has been known to be bent from time to time.) - Kevin, Nov 2000. ]
|
||
*/
|
||
|
||
interp_sect = bfd_get_section_by_name (exec_bfd, ".interp");
|
||
if (interp_sect == NULL
|
||
&& (bfd_get_file_flags (exec_bfd) & DYNAMIC) != 0
|
||
&& (exec_entry_point (exec_bfd, &exec_ops) != pc))
|
||
{
|
||
struct cleanup *old_chain;
|
||
struct section_offsets *new_offsets;
|
||
int i, changed;
|
||
CORE_ADDR displacement;
|
||
|
||
/* It is necessary to relocate the objfile. The amount to
|
||
relocate by is simply the address at which we are stopped
|
||
minus the starting address from the executable.
|
||
|
||
We relocate all of the sections by the same amount. This
|
||
behavior is mandated by recent editions of the System V ABI.
|
||
According to the System V Application Binary Interface,
|
||
Edition 4.1, page 5-5:
|
||
|
||
... Though the system chooses virtual addresses for
|
||
individual processes, it maintains the segments' relative
|
||
positions. Because position-independent code uses relative
|
||
addressesing between segments, the difference between
|
||
virtual addresses in memory must match the difference
|
||
between virtual addresses in the file. The difference
|
||
between the virtual address of any segment in memory and
|
||
the corresponding virtual address in the file is thus a
|
||
single constant value for any one executable or shared
|
||
object in a given process. This difference is the base
|
||
address. One use of the base address is to relocate the
|
||
memory image of the program during dynamic linking.
|
||
|
||
The same language also appears in Edition 4.0 of the System V
|
||
ABI and is left unspecified in some of the earlier editions. */
|
||
|
||
displacement = pc - exec_entry_point (exec_bfd, &exec_ops);
|
||
changed = 0;
|
||
|
||
new_offsets = xcalloc (symfile_objfile->num_sections,
|
||
sizeof (struct section_offsets));
|
||
old_chain = make_cleanup (xfree, new_offsets);
|
||
|
||
for (i = 0; i < symfile_objfile->num_sections; i++)
|
||
{
|
||
if (displacement != ANOFFSET (symfile_objfile->section_offsets, i))
|
||
changed = 1;
|
||
new_offsets->offsets[i] = displacement;
|
||
}
|
||
|
||
if (changed)
|
||
objfile_relocate (symfile_objfile, new_offsets);
|
||
|
||
do_cleanups (old_chain);
|
||
}
|
||
}
|
||
|
||
/*
|
||
|
||
GLOBAL FUNCTION
|
||
|
||
svr4_solib_create_inferior_hook -- shared library startup support
|
||
|
||
SYNOPSIS
|
||
|
||
void svr4_solib_create_inferior_hook ()
|
||
|
||
DESCRIPTION
|
||
|
||
When gdb starts up the inferior, it nurses it along (through the
|
||
shell) until it is ready to execute it's first instruction. At this
|
||
point, this function gets called via expansion of the macro
|
||
SOLIB_CREATE_INFERIOR_HOOK.
|
||
|
||
For SunOS executables, this first instruction is typically the
|
||
one at "_start", or a similar text label, regardless of whether
|
||
the executable is statically or dynamically linked. The runtime
|
||
startup code takes care of dynamically linking in any shared
|
||
libraries, once gdb allows the inferior to continue.
|
||
|
||
For SVR4 executables, this first instruction is either the first
|
||
instruction in the dynamic linker (for dynamically linked
|
||
executables) or the instruction at "start" for statically linked
|
||
executables. For dynamically linked executables, the system
|
||
first exec's /lib/libc.so.N, which contains the dynamic linker,
|
||
and starts it running. The dynamic linker maps in any needed
|
||
shared libraries, maps in the actual user executable, and then
|
||
jumps to "start" in the user executable.
|
||
|
||
For both SunOS shared libraries, and SVR4 shared libraries, we
|
||
can arrange to cooperate with the dynamic linker to discover the
|
||
names of shared libraries that are dynamically linked, and the
|
||
base addresses to which they are linked.
|
||
|
||
This function is responsible for discovering those names and
|
||
addresses, and saving sufficient information about them to allow
|
||
their symbols to be read at a later time.
|
||
|
||
FIXME
|
||
|
||
Between enable_break() and disable_break(), this code does not
|
||
properly handle hitting breakpoints which the user might have
|
||
set in the startup code or in the dynamic linker itself. Proper
|
||
handling will probably have to wait until the implementation is
|
||
changed to use the "breakpoint handler function" method.
|
||
|
||
Also, what if child has exit()ed? Must exit loop somehow.
|
||
*/
|
||
|
||
static void
|
||
svr4_solib_create_inferior_hook (void)
|
||
{
|
||
/* Relocate the main executable if necessary. */
|
||
svr4_relocate_main_executable ();
|
||
|
||
if (!svr4_have_link_map_offsets ())
|
||
return;
|
||
|
||
if (!enable_break ())
|
||
return;
|
||
|
||
#if defined(_SCO_DS)
|
||
/* SCO needs the loop below, other systems should be using the
|
||
special shared library breakpoints and the shared library breakpoint
|
||
service routine.
|
||
|
||
Now run the target. It will eventually hit the breakpoint, at
|
||
which point all of the libraries will have been mapped in and we
|
||
can go groveling around in the dynamic linker structures to find
|
||
out what we need to know about them. */
|
||
|
||
clear_proceed_status ();
|
||
stop_soon = STOP_QUIETLY;
|
||
stop_signal = TARGET_SIGNAL_0;
|
||
do
|
||
{
|
||
target_resume (pid_to_ptid (-1), 0, stop_signal);
|
||
wait_for_inferior ();
|
||
}
|
||
while (stop_signal != TARGET_SIGNAL_TRAP);
|
||
stop_soon = NO_STOP_QUIETLY;
|
||
#endif /* defined(_SCO_DS) */
|
||
}
|
||
|
||
static void
|
||
svr4_clear_solib (void)
|
||
{
|
||
debug_base = 0;
|
||
debug_loader_offset_p = 0;
|
||
debug_loader_offset = 0;
|
||
xfree (debug_loader_name);
|
||
debug_loader_name = NULL;
|
||
}
|
||
|
||
static void
|
||
svr4_free_so (struct so_list *so)
|
||
{
|
||
xfree (so->lm_info->lm);
|
||
xfree (so->lm_info);
|
||
}
|
||
|
||
|
||
/* Clear any bits of ADDR that wouldn't fit in a target-format
|
||
data pointer. "Data pointer" here refers to whatever sort of
|
||
address the dynamic linker uses to manage its sections. At the
|
||
moment, we don't support shared libraries on any processors where
|
||
code and data pointers are different sizes.
|
||
|
||
This isn't really the right solution. What we really need here is
|
||
a way to do arithmetic on CORE_ADDR values that respects the
|
||
natural pointer/address correspondence. (For example, on the MIPS,
|
||
converting a 32-bit pointer to a 64-bit CORE_ADDR requires you to
|
||
sign-extend the value. There, simply truncating the bits above
|
||
gdbarch_ptr_bit, as we do below, is no good.) This should probably
|
||
be a new gdbarch method or something. */
|
||
static CORE_ADDR
|
||
svr4_truncate_ptr (CORE_ADDR addr)
|
||
{
|
||
if (gdbarch_ptr_bit (current_gdbarch) == sizeof (CORE_ADDR) * 8)
|
||
/* We don't need to truncate anything, and the bit twiddling below
|
||
will fail due to overflow problems. */
|
||
return addr;
|
||
else
|
||
return addr & (((CORE_ADDR) 1 << gdbarch_ptr_bit (current_gdbarch)) - 1);
|
||
}
|
||
|
||
|
||
static void
|
||
svr4_relocate_section_addresses (struct so_list *so,
|
||
struct section_table *sec)
|
||
{
|
||
sec->addr = svr4_truncate_ptr (sec->addr + LM_ADDR_CHECK (so,
|
||
sec->bfd));
|
||
sec->endaddr = svr4_truncate_ptr (sec->endaddr + LM_ADDR_CHECK (so,
|
||
sec->bfd));
|
||
}
|
||
|
||
|
||
/* Architecture-specific operations. */
|
||
|
||
/* Per-architecture data key. */
|
||
static struct gdbarch_data *solib_svr4_data;
|
||
|
||
struct solib_svr4_ops
|
||
{
|
||
/* Return a description of the layout of `struct link_map'. */
|
||
struct link_map_offsets *(*fetch_link_map_offsets)(void);
|
||
};
|
||
|
||
/* Return a default for the architecture-specific operations. */
|
||
|
||
static void *
|
||
solib_svr4_init (struct obstack *obstack)
|
||
{
|
||
struct solib_svr4_ops *ops;
|
||
|
||
ops = OBSTACK_ZALLOC (obstack, struct solib_svr4_ops);
|
||
ops->fetch_link_map_offsets = NULL;
|
||
return ops;
|
||
}
|
||
|
||
/* Set the architecture-specific `struct link_map_offsets' fetcher for
|
||
GDBARCH to FLMO. Also, install SVR4 solib_ops into GDBARCH. */
|
||
|
||
void
|
||
set_solib_svr4_fetch_link_map_offsets (struct gdbarch *gdbarch,
|
||
struct link_map_offsets *(*flmo) (void))
|
||
{
|
||
struct solib_svr4_ops *ops = gdbarch_data (gdbarch, solib_svr4_data);
|
||
|
||
ops->fetch_link_map_offsets = flmo;
|
||
|
||
set_solib_ops (gdbarch, &svr4_so_ops);
|
||
}
|
||
|
||
/* Fetch a link_map_offsets structure using the architecture-specific
|
||
`struct link_map_offsets' fetcher. */
|
||
|
||
static struct link_map_offsets *
|
||
svr4_fetch_link_map_offsets (void)
|
||
{
|
||
struct solib_svr4_ops *ops = gdbarch_data (current_gdbarch, solib_svr4_data);
|
||
|
||
gdb_assert (ops->fetch_link_map_offsets);
|
||
return ops->fetch_link_map_offsets ();
|
||
}
|
||
|
||
/* Return 1 if a link map offset fetcher has been defined, 0 otherwise. */
|
||
|
||
static int
|
||
svr4_have_link_map_offsets (void)
|
||
{
|
||
struct solib_svr4_ops *ops = gdbarch_data (current_gdbarch, solib_svr4_data);
|
||
return (ops->fetch_link_map_offsets != NULL);
|
||
}
|
||
|
||
|
||
/* Most OS'es that have SVR4-style ELF dynamic libraries define a
|
||
`struct r_debug' and a `struct link_map' that are binary compatible
|
||
with the origional SVR4 implementation. */
|
||
|
||
/* Fetch (and possibly build) an appropriate `struct link_map_offsets'
|
||
for an ILP32 SVR4 system. */
|
||
|
||
struct link_map_offsets *
|
||
svr4_ilp32_fetch_link_map_offsets (void)
|
||
{
|
||
static struct link_map_offsets lmo;
|
||
static struct link_map_offsets *lmp = NULL;
|
||
|
||
if (lmp == NULL)
|
||
{
|
||
lmp = &lmo;
|
||
|
||
lmo.r_version_offset = 0;
|
||
lmo.r_version_size = 4;
|
||
lmo.r_map_offset = 4;
|
||
lmo.r_ldsomap_offset = 20;
|
||
|
||
/* Everything we need is in the first 20 bytes. */
|
||
lmo.link_map_size = 20;
|
||
lmo.l_addr_offset = 0;
|
||
lmo.l_name_offset = 4;
|
||
lmo.l_ld_offset = 8;
|
||
lmo.l_next_offset = 12;
|
||
lmo.l_prev_offset = 16;
|
||
}
|
||
|
||
return lmp;
|
||
}
|
||
|
||
/* Fetch (and possibly build) an appropriate `struct link_map_offsets'
|
||
for an LP64 SVR4 system. */
|
||
|
||
struct link_map_offsets *
|
||
svr4_lp64_fetch_link_map_offsets (void)
|
||
{
|
||
static struct link_map_offsets lmo;
|
||
static struct link_map_offsets *lmp = NULL;
|
||
|
||
if (lmp == NULL)
|
||
{
|
||
lmp = &lmo;
|
||
|
||
lmo.r_version_offset = 0;
|
||
lmo.r_version_size = 4;
|
||
lmo.r_map_offset = 8;
|
||
lmo.r_ldsomap_offset = 40;
|
||
|
||
/* Everything we need is in the first 40 bytes. */
|
||
lmo.link_map_size = 40;
|
||
lmo.l_addr_offset = 0;
|
||
lmo.l_name_offset = 8;
|
||
lmo.l_ld_offset = 16;
|
||
lmo.l_next_offset = 24;
|
||
lmo.l_prev_offset = 32;
|
||
}
|
||
|
||
return lmp;
|
||
}
|
||
|
||
|
||
struct target_so_ops svr4_so_ops;
|
||
|
||
/* Lookup global symbol for ELF DSOs linked with -Bsymbolic. Those DSOs have a
|
||
different rule for symbol lookup. The lookup begins here in the DSO, not in
|
||
the main executable. */
|
||
|
||
static struct symbol *
|
||
elf_lookup_lib_symbol (const struct objfile *objfile,
|
||
const char *name,
|
||
const char *linkage_name,
|
||
const domain_enum domain, struct symtab **symtab)
|
||
{
|
||
if (objfile->obfd == NULL
|
||
|| scan_dyntag (DT_SYMBOLIC, objfile->obfd, NULL) != 1)
|
||
return NULL;
|
||
|
||
return lookup_global_symbol_from_objfile
|
||
(objfile, name, linkage_name, domain, symtab);
|
||
}
|
||
|
||
extern initialize_file_ftype _initialize_svr4_solib; /* -Wmissing-prototypes */
|
||
|
||
void
|
||
_initialize_svr4_solib (void)
|
||
{
|
||
solib_svr4_data = gdbarch_data_register_pre_init (solib_svr4_init);
|
||
|
||
svr4_so_ops.relocate_section_addresses = svr4_relocate_section_addresses;
|
||
svr4_so_ops.free_so = svr4_free_so;
|
||
svr4_so_ops.clear_solib = svr4_clear_solib;
|
||
svr4_so_ops.solib_create_inferior_hook = svr4_solib_create_inferior_hook;
|
||
svr4_so_ops.special_symbol_handling = svr4_special_symbol_handling;
|
||
svr4_so_ops.current_sos = svr4_current_sos;
|
||
svr4_so_ops.open_symbol_file_object = open_symbol_file_object;
|
||
svr4_so_ops.in_dynsym_resolve_code = svr4_in_dynsym_resolve_code;
|
||
svr4_so_ops.lookup_lib_global_symbol = elf_lookup_lib_symbol;
|
||
}
|