LCOV - code coverage report
Current view: top level - libdwfl - dwfl_build_id_find_elf.c (source / functions) Hit Total Coverage
Test: elfutils-0.191 Lines: 59 81 72.8 %
Date: 2024-07-04 23:49:44 Functions: 3 3 100.0 %
Legend: Lines: hit not hit | Branches: + taken - not taken # not executed Branches: 49 74 66.2 %

           Branch data     Line data    Source code
       1                 :            : /* Find an ELF file for a module from its build ID.
       2                 :            :    Copyright (C) 2007-2010, 2014, 2015, 2019 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                 :            : #include <inttypes.h>
      35                 :            : #include <fcntl.h>
      36                 :            : #include "system.h"
      37                 :            : 
      38                 :            : 
      39                 :            : int
      40                 :            : internal_function
      41                 :        322 : __libdwfl_open_by_build_id (Dwfl_Module *mod, bool debug, char **file_name,
      42                 :            :                             const size_t id_len, const uint8_t *id)
      43                 :            : {
      44                 :            :   /* We don't handle very short or really large build-ids.  We need at
      45                 :            :      at least 3 and allow for up to 64 (normally ids are 20 long).  */
      46                 :            : #define MIN_BUILD_ID_BYTES 3
      47                 :            : #define MAX_BUILD_ID_BYTES 64
      48         [ -  + ]:        322 :   if (id_len < MIN_BUILD_ID_BYTES || id_len > MAX_BUILD_ID_BYTES)
      49                 :            :     {
      50                 :          0 :     bad_id:
      51                 :          0 :       __libdwfl_seterrno (DWFL_E_WRONG_ID_ELF);
      52                 :          0 :       return -1;
      53                 :            :     }
      54                 :            : 
      55                 :            :   /* Search debuginfo_path directories' .build-id/ subdirectories.  */
      56                 :            : 
      57                 :        322 :   char id_name[sizeof "/.build-id/" + 1 + MAX_BUILD_ID_BYTES * 2
      58                 :            :                + sizeof ".debug" - 1];
      59         [ -  + ]:        322 :   strcpy (id_name, "/.build-id/");
      60                 :        322 :   int n = snprintf (&id_name[sizeof "/.build-id/" - 1],
      61         [ -  + ]:        322 :                     4, "%02" PRIx8 "/", (uint8_t) id[0]);
      62         [ -  + ]:        322 :   if (n != 3)
      63                 :          0 :     goto bad_id;;
      64         [ +  + ]:       6440 :   for (size_t i = 1; i < id_len; ++i)
      65                 :            :     {
      66                 :       6118 :       n = snprintf (&id_name[sizeof "/.build-id/" - 1 + 3 + (i - 1) * 2],
      67         [ -  + ]:       6118 :                     3, "%02" PRIx8, (uint8_t) id[i]);
      68         [ -  + ]:       6118 :       if (n != 2)
      69                 :          0 :         goto bad_id;
      70                 :            :     }
      71         [ +  + ]:        322 :   if (debug)
      72                 :        276 :     strcpy (&id_name[sizeof "/.build-id/" - 1 + 3 + (id_len - 1) * 2],
      73                 :            :             ".debug");
      74                 :            : 
      75                 :        322 :   const Dwfl_Callbacks *const cb = mod->dwfl->callbacks;
      76   [ +  +  +  + ]:        322 :   char *path = strdup ((cb->debuginfo_path ? *cb->debuginfo_path : NULL)
      77                 :            :                        ?: DEFAULT_DEBUGINFO_PATH);
      78         [ -  + ]:        322 :   if (path == NULL)
      79                 :            :     return -1;
      80                 :            : 
      81                 :        322 :   int fd = -1;
      82                 :        322 :   char *dir;
      83                 :        322 :   char *paths = path;
      84   [ +  +  +  + ]:       1260 :   while (fd < 0 && (dir = strsep (&paths, ":")) != NULL)
      85                 :            :     {
      86         [ -  + ]:        938 :       if (dir[0] == '+' || dir[0] == '-')
      87                 :          0 :         ++dir;
      88                 :            : 
      89                 :            :       /* Only absolute directory names are useful to us.  */
      90         [ +  + ]:        938 :       if (dir[0] != '/')
      91                 :        628 :         continue;
      92                 :            : 
      93                 :        310 :       size_t dirlen = strlen (dir);
      94                 :        310 :       char *name = malloc (dirlen + sizeof id_name);
      95         [ +  - ]:        310 :       if (unlikely (name == NULL))
      96                 :            :         break;
      97                 :        310 :       memcpy (mempcpy (name, dir, dirlen), id_name, sizeof id_name);
      98                 :            : 
      99   [ +  +  -  + ]:        310 :       fd = TEMP_FAILURE_RETRY (open (name, O_RDONLY));
     100         [ +  + ]:        310 :       if (fd >= 0)
     101                 :            :         {
     102         [ -  + ]:         32 :           if (*file_name != NULL)
     103                 :          0 :             free (*file_name);
     104         [ +  - ]:         32 :           *file_name = realpath (name, NULL);
     105         [ +  - ]:         32 :           if (*file_name == NULL)
     106                 :            :             {
     107                 :          0 :               *file_name = name;
     108                 :          0 :               name = NULL;
     109                 :            :             }
     110                 :            :         }
     111                 :        310 :       free (name);
     112                 :            :     }
     113                 :            : 
     114                 :        322 :   free (path);
     115                 :            : 
     116                 :            :   /* If we simply found nothing, clear errno.  If we had some other error
     117                 :            :      with the file, report that.  Possibly this should treat other errors
     118                 :            :      like ENOENT too.  But ignoring all errors could mask some that should
     119                 :            :      be reported.  */
     120   [ +  +  +  + ]:        322 :   if (fd < 0 && errno == ENOENT)
     121                 :        278 :     errno = 0;
     122                 :            : 
     123                 :            :   return fd;
     124                 :            : }
     125                 :            : 
     126                 :            : int
     127                 :            : internal_function
     128                 :        278 : __libdwfl_open_mod_by_build_id (Dwfl_Module *mod, bool debug, char **file_name)
     129                 :            : {
     130                 :            :   /* If *FILE_NAME was primed into the module, leave it there
     131                 :            :      as the fallback when we have nothing to offer.  */
     132                 :        278 :   errno = 0;
     133         [ +  - ]:        278 :   if (mod->build_id_len <= 0)
     134                 :            :     return -1;
     135                 :            : 
     136                 :        278 :   const size_t id_len = mod->build_id_len;
     137                 :        278 :   const uint8_t *id = mod->build_id_bits;
     138                 :            : 
     139                 :        278 :   return __libdwfl_open_by_build_id (mod, debug, file_name, id_len, id);
     140                 :            : }
     141                 :            : 
     142                 :            : int
     143                 :         70 : dwfl_build_id_find_elf (Dwfl_Module *mod,
     144                 :            :                         void **userdata __attribute__ ((unused)),
     145                 :            :                         const char *modname __attribute__ ((unused)),
     146                 :            :                         Dwarf_Addr base __attribute__ ((unused)),
     147                 :            :                         char **file_name, Elf **elfp)
     148                 :            : {
     149                 :         70 :   *elfp = NULL;
     150         [ +  + ]:         70 :   if (mod->is_executable
     151         [ +  - ]:         26 :       && mod->dwfl->user_core != NULL
     152         [ +  + ]:         26 :       && mod->dwfl->user_core->executable_for_core != NULL)
     153                 :            :     {
     154                 :            :       /* When dwfl_core_file_report was called with a non-NULL executable file
     155                 :            :          name this callback will replace the Dwfl_Module main.name with the
     156                 :            :          recorded executable file when MOD was identified as main executable
     157                 :            :          (which then triggers opening and reporting of the executable).  */
     158                 :         24 :       const char *executable = mod->dwfl->user_core->executable_for_core;
     159                 :         24 :       int fd = open (executable, O_RDONLY);
     160         [ +  - ]:         24 :       if (fd >= 0)
     161                 :            :         {
     162                 :         24 :           *file_name = strdup (executable);
     163         [ -  + ]:         24 :           if (*file_name != NULL)
     164                 :            :             return fd;
     165                 :            :           else
     166                 :          0 :             close (fd);
     167                 :            :         }
     168                 :            :     }
     169                 :         46 :   int fd = __libdwfl_open_mod_by_build_id (mod, false, file_name);
     170         [ -  + ]:         46 :   if (fd >= 0)
     171                 :            :     {
     172                 :          0 :       Dwfl_Error error = __libdw_open_file (&fd, elfp, true, false);
     173         [ #  # ]:          0 :       if (error != DWFL_E_NOERROR)
     174                 :          0 :         __libdwfl_seterrno (error);
     175         [ #  # ]:          0 :       else if (__libdwfl_find_build_id (mod, false, *elfp) == 2)
     176                 :            :         {
     177                 :            :           /* This is a backdoor signal to short-circuit the ID refresh.  */
     178                 :          0 :           mod->main.valid = true;
     179                 :          0 :           return fd;
     180                 :            :         }
     181                 :            :       else
     182                 :            :         {
     183                 :            :           /* This file does not contain the ID it should!  */
     184                 :          0 :           elf_end (*elfp);
     185                 :          0 :           *elfp = NULL;
     186                 :          0 :           close (fd);
     187                 :          0 :           fd = -1;
     188                 :            :         }
     189                 :          0 :       free (*file_name);
     190                 :          0 :       *file_name = NULL;
     191                 :            :     }
     192                 :            :   else
     193                 :            :     {
     194                 :            : #ifdef ENABLE_LIBDEBUGINFOD
     195                 :            :       /* If all else fails and a build-id is available, query the
     196                 :            :          debuginfo-server if enabled.  */
     197         [ +  - ]:         46 :       if (fd < 0 && mod->build_id_len > 0)
     198                 :         46 :         fd = __libdwfl_debuginfod_find_executable (mod->dwfl,
     199                 :         46 :                                                    mod->build_id_bits,
     200                 :            :                                                    mod->build_id_len);
     201                 :            : #endif
     202                 :            :     }
     203                 :            : 
     204   [ +  -  +  +  :         46 :   if (fd < 0 && errno == 0 && mod->build_id_len > 0)
                   -  + ]
     205                 :            :     /* Setting this with no file yet loaded is a marker that
     206                 :            :        the build ID is authoritative even if we also know a
     207                 :            :        putative *FILE_NAME.  */
     208                 :         34 :     mod->main.valid = true;
     209                 :            : 
     210                 :            :   return fd;
     211                 :            : }
     212                 :            : INTDEF (dwfl_build_id_find_elf)

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