Line data    Source code

       1             : /* Returns the file name and crc stored in the .gnu_debuglink if found.
       2             :    Copyright (C) 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 "libdwelfP.h"
      34             : 
      35             : const char *
      36         125 : dwelf_elf_gnu_debuglink (Elf *elf, GElf_Word *crc)
      37             : {
      38             :   size_t shstrndx;
      39         125 :   if (elf_getshdrstrndx (elf, &shstrndx) < 0)
      40             :     return NULL;
      41             : 
      42             :   Elf_Scn *scn = NULL;
      43        2592 :   while ((scn = elf_nextscn (elf, scn)) != NULL)
      44             :     {
      45             :       GElf_Shdr shdr_mem;
      46        2527 :       GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);
      47        2527 :       if (shdr == NULL)
      48           0 :         return NULL;
      49             : 
      50        2527 :       const char *name = elf_strptr (elf, shstrndx, shdr->sh_name);
      51        2527 :       if (name == NULL)
      52             :         return NULL;
      53             : 
      54        2527 :       if (!strcmp (name, ".gnu_debuglink"))
      55             :         break;
      56             :     }
      57             : 
      58         125 :   if (scn == NULL)
      59             :     return NULL;
      60             : 
      61             :   /* Found the .gnu_debuglink section.  Extract its contents.  */
      62          60 :   Elf_Data *rawdata = elf_rawdata (scn, NULL);
      63          60 :   if (rawdata == NULL || rawdata->d_buf == NULL)
      64             :     return NULL;
      65             : 
      66             :   /* The CRC comes after the zero-terminated file name,
      67             :      (aligned up to 4 bytes) at the end of the section data.  */
      68          60 :   if (rawdata->d_size <= sizeof *crc
      69          60 :       || memchr (rawdata->d_buf, '\0', rawdata->d_size - sizeof *crc) == NULL)
      70             :     return NULL;
      71             : 
      72          60 :   Elf_Data crcdata =
      73             :     {
      74             :       .d_type = ELF_T_WORD,
      75             :       .d_buf = crc,
      76             :       .d_size = sizeof *crc,
      77             :       .d_version = EV_CURRENT,
      78             :     };
      79         120 :   Elf_Data conv =
      80             :     {
      81             :       .d_type = ELF_T_WORD,
      82          60 :       .d_buf = rawdata->d_buf + rawdata->d_size - sizeof *crc,
      83             :       .d_size = sizeof *crc,
      84             :       .d_version = EV_CURRENT,
      85             :     };
      86             : 
      87             :   GElf_Ehdr ehdr_mem;
      88          60 :   GElf_Ehdr *ehdr = gelf_getehdr (elf, &ehdr_mem);
      89          60 :   if (ehdr == NULL)
      90             :     return NULL;
      91             : 
      92          60 :   Elf_Data *d = gelf_xlatetom (elf, &crcdata, &conv, ehdr->e_ident[EI_DATA]);
      93          60 :   if (d == NULL)
      94             :     return NULL;
      95          60 :   assert (d == &crcdata);
      96             : 
      97          60 :   return rawdata->d_buf;
      98             : }
      99             : INTDEF(dwelf_elf_gnu_debuglink)