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221 lines
6.4 KiB
221 lines
6.4 KiB
/* Find debugging and symbol information for a module in libdwfl.
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Copyright (C) 2006-2014 Red Hat, Inc.
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This file is part of elfutils.
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This file is free software; you can redistribute it and/or modify
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it under the terms of either
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* the GNU Lesser General Public License as published by the Free
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Software Foundation; either version 3 of the License, or (at
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your option) any later version
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or
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* the GNU General Public License as published by the Free
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Software Foundation; either version 2 of the License, or (at
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your option) any later version
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or both in parallel, as here.
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elfutils is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received copies of the GNU General Public License and
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the GNU Lesser General Public License along with this program. If
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not, see <http://www.gnu.org/licenses/>. */
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#include "libdwflP.h"
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const char *
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internal_function
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__libdwfl_getsym (Dwfl_Module *mod, int ndx, GElf_Sym *sym, GElf_Addr *addr,
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GElf_Word *shndxp, Elf **elfp, Dwarf_Addr *biasp,
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bool *resolved, bool adjust_st_value)
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{
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if (unlikely (mod == NULL))
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return NULL;
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if (unlikely (mod->symdata == NULL))
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{
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int result = INTUSE(dwfl_module_getsymtab) (mod);
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if (result < 0)
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return NULL;
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}
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/* All local symbols should come before all global symbols. If we
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have an auxiliary table make sure all the main locals come first,
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then all aux locals, then all main globals and finally all aux globals.
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And skip the auxiliary table zero undefined entry. */
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GElf_Word shndx;
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int tndx = ndx;
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int skip_aux_zero = (mod->syments > 0 && mod->aux_syments > 0) ? 1 : 0;
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Elf *elf;
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Elf_Data *symdata;
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Elf_Data *symxndxdata;
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Elf_Data *symstrdata;
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if (mod->aux_symdata == NULL
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|| ndx < mod->first_global)
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{
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/* main symbol table (locals). */
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tndx = ndx;
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elf = mod->symfile->elf;
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symdata = mod->symdata;
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symxndxdata = mod->symxndxdata;
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symstrdata = mod->symstrdata;
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}
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else if (ndx < mod->first_global + mod->aux_first_global - skip_aux_zero)
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{
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/* aux symbol table (locals). */
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tndx = ndx - mod->first_global + skip_aux_zero;
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elf = mod->aux_sym.elf;
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symdata = mod->aux_symdata;
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symxndxdata = mod->aux_symxndxdata;
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symstrdata = mod->aux_symstrdata;
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}
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else if ((size_t) ndx < mod->syments + mod->aux_first_global - skip_aux_zero)
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{
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/* main symbol table (globals). */
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tndx = ndx - mod->aux_first_global + skip_aux_zero;
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elf = mod->symfile->elf;
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symdata = mod->symdata;
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symxndxdata = mod->symxndxdata;
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symstrdata = mod->symstrdata;
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}
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else
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{
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/* aux symbol table (globals). */
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tndx = ndx - mod->syments + skip_aux_zero;
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elf = mod->aux_sym.elf;
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symdata = mod->aux_symdata;
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symxndxdata = mod->aux_symxndxdata;
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symstrdata = mod->aux_symstrdata;
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}
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sym = gelf_getsymshndx (symdata, symxndxdata, tndx, sym, &shndx);
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if (unlikely (sym == NULL))
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{
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__libdwfl_seterrno (DWFL_E_LIBELF);
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return NULL;
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}
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if (sym->st_shndx != SHN_XINDEX)
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shndx = sym->st_shndx;
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/* Figure out whether this symbol points into an SHF_ALLOC section. */
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bool alloc = true;
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if ((shndxp != NULL || mod->e_type != ET_REL)
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&& (sym->st_shndx == SHN_XINDEX
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|| (sym->st_shndx < SHN_LORESERVE && sym->st_shndx != SHN_UNDEF)))
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{
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GElf_Shdr shdr_mem;
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GElf_Shdr *shdr = gelf_getshdr (elf_getscn (elf, shndx), &shdr_mem);
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alloc = unlikely (shdr == NULL) || (shdr->sh_flags & SHF_ALLOC);
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}
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/* In case of an value in an allocated section the main Elf Ebl
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might know where the real value is (e.g. for function
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descriptors). */
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char *ident;
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GElf_Addr st_value = sym->st_value & ebl_func_addr_mask (mod->ebl);
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*resolved = false;
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if (! adjust_st_value && mod->e_type != ET_REL && alloc
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&& (GELF_ST_TYPE (sym->st_info) == STT_FUNC
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|| (GELF_ST_TYPE (sym->st_info) == STT_GNU_IFUNC
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&& (ident = elf_getident (elf, NULL)) != NULL
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&& ident[EI_OSABI] == ELFOSABI_LINUX)))
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{
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if (likely (__libdwfl_module_getebl (mod) == DWFL_E_NOERROR))
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{
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if (elf != mod->main.elf)
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{
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st_value = dwfl_adjusted_st_value (mod, elf, st_value);
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st_value = dwfl_deadjust_st_value (mod, mod->main.elf, st_value);
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}
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*resolved = ebl_resolve_sym_value (mod->ebl, &st_value);
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if (! *resolved)
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st_value = sym->st_value;
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}
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}
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if (shndxp != NULL)
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/* Yield -1 in case of a non-SHF_ALLOC section. */
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*shndxp = alloc ? shndx : (GElf_Word) -1;
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switch (sym->st_shndx)
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{
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case SHN_ABS: /* XXX sometimes should use bias?? */
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case SHN_UNDEF:
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case SHN_COMMON:
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break;
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default:
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if (mod->e_type == ET_REL)
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{
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/* In an ET_REL file, the symbol table values are relative
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to the section, not to the module's load base. */
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size_t symshstrndx = SHN_UNDEF;
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Dwfl_Error result = __libdwfl_relocate_value (mod, elf,
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&symshstrndx,
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shndx, &st_value);
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if (unlikely (result != DWFL_E_NOERROR))
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{
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__libdwfl_seterrno (result);
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return NULL;
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}
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}
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else if (alloc)
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/* Apply the bias to the symbol value. */
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st_value = dwfl_adjusted_st_value (mod,
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*resolved ? mod->main.elf : elf,
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st_value);
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break;
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}
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if (adjust_st_value)
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sym->st_value = st_value;
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if (addr != NULL)
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*addr = st_value;
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if (unlikely (sym->st_name >= symstrdata->d_size))
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{
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__libdwfl_seterrno (DWFL_E_BADSTROFF);
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return NULL;
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}
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if (elfp)
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*elfp = elf;
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if (biasp)
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*biasp = dwfl_adjusted_st_value (mod, elf, 0);
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return (const char *) symstrdata->d_buf + sym->st_name;
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}
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const char *
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dwfl_module_getsym_info (Dwfl_Module *mod, int ndx,
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GElf_Sym *sym, GElf_Addr *addr,
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GElf_Word *shndxp,
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Elf **elfp, Dwarf_Addr *bias)
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{
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bool resolved;
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return __libdwfl_getsym (mod, ndx, sym, addr, shndxp, elfp, bias,
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&resolved, false);
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}
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INTDEF (dwfl_module_getsym_info)
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const char *
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dwfl_module_getsym (Dwfl_Module *mod, int ndx,
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GElf_Sym *sym, GElf_Word *shndxp)
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{
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bool resolved;
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return __libdwfl_getsym (mod, ndx, sym, NULL, shndxp, NULL, NULL,
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&resolved, true);
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}
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INTDEF (dwfl_module_getsym)
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