LCOV - code coverage report
Current view: top level - libdwfl - dwfl_module_getsym.c (source / functions) Hit Total Coverage
Test: elfutils-0.173 Lines: 79 85 92.9 %
Date: 2018-06-29 23:49:12 Functions: 3 3 100.0 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : /* Find debugging and symbol information for a module in libdwfl.
       2             :    Copyright (C) 2006-2014 Red Hat, Inc.
       3             :    This file is part of elfutils.
       4             : 
       5             :    This file is free software; you can redistribute it and/or modify
       6             :    it under the terms of either
       7             : 
       8             :      * the GNU Lesser General Public License as published by the Free
       9             :        Software Foundation; either version 3 of the License, or (at
      10             :        your option) any later version
      11             : 
      12             :    or
      13             : 
      14             :      * the GNU General Public License as published by the Free
      15             :        Software Foundation; either version 2 of the License, or (at
      16             :        your option) any later version
      17             : 
      18             :    or both in parallel, as here.
      19             : 
      20             :    elfutils is distributed in the hope that it will be useful, but
      21             :    WITHOUT ANY WARRANTY; without even the implied warranty of
      22             :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      23             :    General Public License for more details.
      24             : 
      25             :    You should have received copies of the GNU General Public License and
      26             :    the GNU Lesser General Public License along with this program.  If
      27             :    not, see <http://www.gnu.org/licenses/>.  */
      28             : 
      29             : #ifdef HAVE_CONFIG_H
      30             : # include <config.h>
      31             : #endif
      32             : 
      33             : #include "libdwflP.h"
      34             : 
      35             : const char *
      36             : internal_function
      37   753131362 : __libdwfl_getsym (Dwfl_Module *mod, int ndx, GElf_Sym *sym, GElf_Addr *addr,
      38             :                   GElf_Word *shndxp, Elf **elfp, Dwarf_Addr *biasp,
      39             :                   bool *resolved, bool adjust_st_value)
      40             : {
      41   753131362 :   if (unlikely (mod == NULL))
      42             :     return NULL;
      43             : 
      44   753131362 :   if (unlikely (mod->symdata == NULL))
      45             :     {
      46          35 :       int result = INTUSE(dwfl_module_getsymtab) (mod);
      47          35 :       if (result < 0)
      48             :         return NULL;
      49             :     }
      50             : 
      51             :   /* All local symbols should come before all global symbols.  If we
      52             :      have an auxiliary table make sure all the main locals come first,
      53             :      then all aux locals, then all main globals and finally all aux globals.
      54             :      And skip the auxiliary table zero undefined entry.  */
      55             :   GElf_Word shndx;
      56   753131362 :   int tndx = ndx;
      57   753131362 :   int skip_aux_zero = (mod->syments > 0 && mod->aux_syments > 0) ? 1 : 0;
      58             :   Elf *elf;
      59             :   Elf_Data *symdata;
      60             :   Elf_Data *symxndxdata;
      61             :   Elf_Data *symstrdata;
      62   753131362 :   if (mod->aux_symdata == NULL
      63        2105 :       || ndx < mod->first_global)
      64             :     {
      65             :       /* main symbol table (locals).  */
      66   753129304 :       tndx = ndx;
      67   753129304 :       elf = mod->symfile->elf;
      68   753129304 :       symdata = mod->symdata;
      69   753129304 :       symxndxdata = mod->symxndxdata;
      70   753129304 :       symstrdata = mod->symstrdata;
      71             :     }
      72        2058 :   else if (ndx < mod->first_global + mod->aux_first_global - skip_aux_zero)
      73             :     {
      74             :       /* aux symbol table (locals).  */
      75        1188 :       tndx = ndx - mod->first_global + skip_aux_zero;
      76        1188 :       elf = mod->aux_sym.elf;
      77        1188 :       symdata = mod->aux_symdata;
      78        1188 :       symxndxdata = mod->aux_symxndxdata;
      79        1188 :       symstrdata = mod->aux_symstrdata;
      80             :     }
      81         870 :   else if ((size_t) ndx < mod->syments + mod->aux_first_global - skip_aux_zero)
      82             :     {
      83             :       /* main symbol table (globals).  */
      84         586 :       tndx = ndx - mod->aux_first_global + skip_aux_zero;
      85         586 :       elf = mod->symfile->elf;
      86         586 :       symdata = mod->symdata;
      87         586 :       symxndxdata = mod->symxndxdata;
      88         586 :       symstrdata = mod->symstrdata;
      89             :     }
      90             :   else
      91             :     {
      92             :       /* aux symbol table (globals).  */
      93         284 :       tndx = ndx - mod->syments + skip_aux_zero;
      94         284 :       elf = mod->aux_sym.elf;
      95         284 :       symdata = mod->aux_symdata;
      96         284 :       symxndxdata = mod->aux_symxndxdata;
      97         284 :       symstrdata = mod->aux_symstrdata;
      98             :     }
      99   753131362 :   sym = gelf_getsymshndx (symdata, symxndxdata, tndx, sym, &shndx);
     100             : 
     101   753131362 :   if (unlikely (sym == NULL))
     102             :     {
     103           0 :       __libdwfl_seterrno (DWFL_E_LIBELF);
     104           0 :       return NULL;
     105             :     }
     106             : 
     107   753131362 :   if (sym->st_shndx != SHN_XINDEX)
     108   753131362 :     shndx = sym->st_shndx;
     109             : 
     110             :   /* Figure out whether this symbol points into an SHF_ALLOC section.  */
     111   753131362 :   bool alloc = true;
     112   753131362 :   if ((shndxp != NULL || mod->e_type != ET_REL)
     113   753131362 :       && (sym->st_shndx == SHN_XINDEX
     114   753131362 :           || (sym->st_shndx < SHN_LORESERVE && sym->st_shndx != SHN_UNDEF)))
     115             :     {
     116             :       GElf_Shdr shdr_mem;
     117   625601937 :       GElf_Shdr *shdr = gelf_getshdr (elf_getscn (elf, shndx), &shdr_mem);
     118   625601937 :       alloc = unlikely (shdr == NULL) || (shdr->sh_flags & SHF_ALLOC);
     119             :     }
     120             : 
     121             :   /* In case of an value in an allocated section the main Elf Ebl
     122             :      might know where the real value is (e.g. for function
     123             :      descriptors).  */
     124             : 
     125             :   char *ident;
     126   753131362 :   GElf_Addr st_value = sym->st_value & ebl_func_addr_mask (mod->ebl);
     127   753131362 :   *resolved = false;
     128   753131362 :   if (! adjust_st_value && mod->e_type != ET_REL && alloc
     129   743108310 :       && (GELF_ST_TYPE (sym->st_info) == STT_FUNC
     130   418976906 :           || (GELF_ST_TYPE (sym->st_info) == STT_GNU_IFUNC
     131        2523 :               && (ident = elf_getident (elf, NULL)) != NULL
     132        2523 :               && ident[EI_OSABI] == ELFOSABI_LINUX)))
     133             :     {
     134   324133927 :       if (likely (__libdwfl_module_getebl (mod) == DWFL_E_NOERROR))
     135             :         {
     136   324133927 :           if (elf != mod->main.elf)
     137             :             {
     138        3420 :               st_value = dwfl_adjusted_st_value (mod, elf, st_value);
     139        3420 :               st_value = dwfl_deadjust_st_value (mod, mod->main.elf, st_value);
     140             :             }
     141             : 
     142   324133927 :           *resolved = ebl_resolve_sym_value (mod->ebl, &st_value);
     143   324133927 :           if (! *resolved)
     144   324133212 :             st_value = sym->st_value;
     145             :         }
     146             :     }
     147             : 
     148   753131362 :   if (shndxp != NULL)
     149             :     /* Yield -1 in case of a non-SHF_ALLOC section.  */
     150   753129230 :     *shndxp = alloc ? shndx : (GElf_Word) -1;
     151             : 
     152   753131362 :   switch (sym->st_shndx)
     153             :     {
     154             :     case SHN_ABS:               /* XXX sometimes should use bias?? */
     155             :     case SHN_UNDEF:
     156             :     case SHN_COMMON:
     157             :       break;
     158             : 
     159             :     default:
     160   625601937 :       if (mod->e_type == ET_REL)
     161             :         {
     162             :           /* In an ET_REL file, the symbol table values are relative
     163             :              to the section, not to the module's load base.  */
     164     3460314 :           size_t symshstrndx = SHN_UNDEF;
     165     3460314 :           Dwfl_Error result = __libdwfl_relocate_value (mod, elf,
     166             :                                                         &symshstrndx,
     167             :                                                         shndx, &st_value);
     168     3460314 :           if (unlikely (result != DWFL_E_NOERROR))
     169             :             {
     170           0 :               __libdwfl_seterrno (result);
     171           0 :               return NULL;
     172             :             }
     173             :         }
     174   622141623 :       else if (alloc)
     175             :         /* Apply the bias to the symbol value.  */
     176  1858737768 :         st_value = dwfl_adjusted_st_value (mod,
     177   619579256 :                                            *resolved ? mod->main.elf : elf,
     178             :                                            st_value);
     179             :       break;
     180             :     }
     181             : 
     182   753131362 :   if (adjust_st_value)
     183        1232 :     sym->st_value = st_value;
     184             : 
     185   753131362 :   if (addr != NULL)
     186   753130130 :     *addr = st_value;
     187             : 
     188   753131362 :   if (unlikely (sym->st_name >= symstrdata->d_size))
     189             :     {
     190           0 :       __libdwfl_seterrno (DWFL_E_BADSTROFF);
     191           0 :       return NULL;
     192             :     }
     193   753131362 :   if (elfp)
     194   753127998 :     *elfp = elf;
     195   753131362 :   if (biasp)
     196        1232 :     *biasp = dwfl_adjusted_st_value (mod, elf, 0);
     197   753131362 :   return (const char *) symstrdata->d_buf + sym->st_name;
     198             : }
     199             : 
     200             : const char *
     201        3364 : dwfl_module_getsym_info (Dwfl_Module *mod, int ndx,
     202             :                          GElf_Sym *sym, GElf_Addr *addr,
     203             :                          GElf_Word *shndxp,
     204             :                          Elf **elfp, Dwarf_Addr *bias)
     205             : {
     206             :   bool resolved;
     207        3364 :   return __libdwfl_getsym (mod, ndx, sym, addr, shndxp, elfp, bias,
     208             :                            &resolved, false);
     209             : }
     210             : INTDEF (dwfl_module_getsym_info)
     211             : 
     212             : const char *
     213        1232 : dwfl_module_getsym (Dwfl_Module *mod, int ndx,
     214             :                     GElf_Sym *sym, GElf_Word *shndxp)
     215             : {
     216             :   bool resolved;
     217        1232 :   return __libdwfl_getsym (mod, ndx, sym, NULL, shndxp, NULL, NULL,
     218             :                            &resolved, true);
     219             : }
     220             : INTDEF (dwfl_module_getsym)

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