LCOV - code coverage report
Current view: top level - libelf - nlist.c (source / functions) Hit Total Coverage
Test: elfutils-0.190 Lines: 70 87 80.5 %
Date: 2023-11-14 00:32:03 Functions: 1 1 100.0 %
Legend: Lines: hit not hit | Branches: + taken - not taken # not executed Branches: 27 40 67.5 %

           Branch data     Line data    Source code
       1                 :            : /* Extract symbol list from binary.
       2                 :            :    Copyright (C) 1998, 1999, 2000, 2001, 2002, 2005, 2007, 2015 Red Hat, Inc.
       3                 :            :    This file is part of elfutils.
       4                 :            :    Written by Ulrich Drepper <drepper@redhat.com>, 1998.
       5                 :            : 
       6                 :            :    This file is free software; you can redistribute it and/or modify
       7                 :            :    it under the terms of either
       8                 :            : 
       9                 :            :      * the GNU Lesser General Public License as published by the Free
      10                 :            :        Software Foundation; either version 3 of the License, or (at
      11                 :            :        your option) any later version
      12                 :            : 
      13                 :            :    or
      14                 :            : 
      15                 :            :      * the GNU General Public License as published by the Free
      16                 :            :        Software Foundation; either version 2 of the License, or (at
      17                 :            :        your option) any later version
      18                 :            : 
      19                 :            :    or both in parallel, as here.
      20                 :            : 
      21                 :            :    elfutils is distributed in the hope that it will be useful, but
      22                 :            :    WITHOUT ANY WARRANTY; without even the implied warranty of
      23                 :            :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      24                 :            :    General Public License for more details.
      25                 :            : 
      26                 :            :    You should have received copies of the GNU General Public License and
      27                 :            :    the GNU Lesser General Public License along with this program.  If
      28                 :            :    not, see <http://www.gnu.org/licenses/>.  */
      29                 :            : 
      30                 :            : #ifdef HAVE_CONFIG_H
      31                 :            : # include <config.h>
      32                 :            : #endif
      33                 :            : 
      34                 :            : #include <fcntl.h>
      35                 :            : #include <gelf.h>
      36                 :            : #include <libelf.h>
      37                 :            : #include <nlist.h>
      38                 :            : 
      39                 :            : #include "libelfP.h"
      40                 :            : 
      41                 :            : 
      42                 :            : struct hashentry
      43                 :            : {
      44                 :            :   const char *str;
      45                 :            :   GElf_Sym sym;
      46                 :            : };
      47                 :            : #define TYPE struct hashentry
      48                 :            : /* XXX Use a better hash function some day.  */
      49                 :            : #define HASHFCT(str, len) INTUSE(elf_hash) (str)
      50                 :            : #define COMPARE(p1, p2) strcmp ((p1)->str, (p2)->str)
      51                 :            : #define CLASS static
      52                 :            : #define PREFIX nlist_
      53                 :            : #define xcalloc(n, m) calloc (n, m)
      54                 :            : #define next_prime(s) __libelf_next_prime (s)
      55                 :            : #include <fixedsizehash.h>
      56                 :            : 
      57                 :            : 
      58                 :            : int
      59                 :          4 : nlist (const char *filename, struct nlist *nl)
      60                 :            : {
      61                 :          4 :   int fd;
      62                 :          4 :   Elf *elf;
      63                 :          4 :   Elf_Scn *scn = NULL;
      64                 :          4 :   Elf_Scn *symscn = NULL;
      65                 :          4 :   GElf_Shdr shdr_mem;
      66                 :          4 :   GElf_Shdr *shdr = NULL;
      67                 :          4 :   Elf_Data *data;
      68                 :          4 :   struct nlist_fshash *table;
      69                 :          4 :   size_t nsyms;
      70                 :          4 :   size_t cnt;
      71                 :            : 
      72                 :            :   /* Open the file.  */
      73                 :          4 :   fd = open (filename, O_RDONLY);
      74         [ +  + ]:          4 :   if (fd == -1)
      75                 :            :     {
      76                 :          2 :       __libelf_seterrno (ELF_E_NOFILE);
      77                 :          2 :       goto fail;
      78                 :            :     }
      79                 :            : 
      80                 :            :   /* For compatibility reasons (`nlist' existed before ELF and libelf)
      81                 :            :      we don't expect the caller to set the ELF version.  Do this here
      82                 :            :      as if it hasn't happened yet.  */
      83                 :          2 :   INTUSE(elf_version) (EV_CURRENT);
      84                 :            : 
      85                 :            :   /* Now get an ELF descriptor.  */
      86                 :          2 :   elf = INTUSE(elf_begin) (fd, ELF_C_READ_MMAP, NULL);
      87         [ -  + ]:          2 :   if (elf == NULL)
      88                 :          0 :     goto fail_fd;
      89                 :            : 
      90                 :            :   /* Find a symbol table.  We prefer the real symbol table but if it
      91                 :            :      does not exist use the dynamic symbol table.  */
      92         [ +  - ]:         76 :   while ((scn = INTUSE(elf_nextscn) (elf, scn)) != NULL)
      93                 :            :     {
      94                 :         76 :       shdr = INTUSE(gelf_getshdr) (scn, &shdr_mem);
      95         [ -  + ]:         76 :       if (shdr == NULL)
      96                 :          0 :         goto fail_close;
      97                 :            : 
      98                 :            :       /* That is what we are looking for.  */
      99         [ +  + ]:         76 :       if (shdr->sh_type == SHT_SYMTAB)
     100                 :            :         {
     101                 :            :           symscn = scn;
     102                 :            :           break;
     103                 :            :         }
     104                 :            : 
     105                 :            :       /* Better than nothing.  Remember this section.  */
     106         [ +  + ]:         74 :       if (shdr->sh_type == SHT_DYNSYM)
     107                 :          2 :         symscn = scn;
     108                 :            :     }
     109                 :            : 
     110         [ -  + ]:          2 :   if (symscn == NULL)
     111                 :            :     /* We haven't found anything.  Fail.  */
     112                 :          0 :     goto fail_close;
     113                 :            : 
     114                 :            :   /* Re-get the section header in case we found only the dynamic symbol
     115                 :            :      table.  */
     116         [ -  + ]:          2 :   if (scn == NULL)
     117                 :            :     {
     118                 :          0 :       shdr = INTUSE(gelf_getshdr) (symscn, &shdr_mem);
     119         [ #  # ]:          0 :       if (unlikely (shdr == NULL))
     120                 :          0 :         goto fail_close;
     121                 :            :     }
     122                 :            :   /* SHDR->SH_LINK now contains the index of the string section.  */
     123                 :            : 
     124                 :            :   /* Get the data for the symbol section.  */
     125                 :          2 :   data = INTUSE(elf_getdata) (symscn, NULL);
     126         [ -  + ]:          2 :   if (data == NULL)
     127                 :          0 :     goto fail_close;
     128                 :            : 
     129                 :            :   /* How many symbols are there?  */
     130                 :          4 :   nsyms = (shdr->sh_size
     131                 :          2 :            / INTUSE(gelf_fsize) (elf, ELF_T_SYM, 1, EV_CURRENT));
     132                 :            : 
     133                 :            :   /* Create the hash table.  */
     134                 :          2 :   table = nlist_fshash_init (nsyms);
     135         [ -  + ]:          2 :   if (table == NULL)
     136                 :            :     {
     137                 :          0 :       __libelf_seterrno (ELF_E_NOMEM);
     138                 :          0 :       goto fail_close;
     139                 :            :     }
     140                 :            : 
     141                 :            :   /* Iterate over all the symbols in the section.  */
     142         [ +  + ]:       1180 :   for (cnt = 0; cnt < nsyms; ++cnt)
     143                 :            :     {
     144                 :       1178 :       struct hashentry mem;
     145                 :       1178 :       GElf_Sym *sym;
     146                 :            : 
     147                 :            :       /* Get the symbol.  */
     148                 :       1178 :       sym = INTUSE(gelf_getsym) (data, cnt, &mem.sym);
     149         [ -  + ]:       1178 :       if (sym == NULL)
     150                 :          0 :         goto fail_dealloc;
     151                 :            : 
     152                 :            :       /* Get the name of the symbol.  */
     153                 :       1178 :       mem.str = INTUSE(elf_strptr) (elf, shdr->sh_link, sym->st_name);
     154         [ -  + ]:       1178 :       if (mem.str == NULL)
     155                 :          0 :         goto fail_dealloc;
     156                 :            : 
     157                 :            :       /* Don't allow zero-length strings.  */
     158         [ +  + ]:       1178 :       if (mem.str[0] == '\0')
     159                 :          4 :         continue;
     160                 :            : 
     161                 :            :       /* And add it to the hash table.  Note that we are using the
     162                 :            :          overwrite version.  This will ensure that
     163                 :            :          a) global symbols are preferred over local symbols since
     164                 :            :             they are all located at the end
     165                 :            :          b) if there are multiple local symbols with the same name
     166                 :            :             the last one is used.
     167                 :            :       */
     168                 :       1174 :       (void) nlist_fshash_overwrite (table, mem.str, 0, &mem);
     169                 :            :     }
     170                 :            : 
     171                 :            :   /* Now it is time to look for the symbols the user asked for.
     172                 :            :      XXX What is a `null name/null string'?  This is what the
     173                 :            :      standard says terminates the list.  Is it a null pointer
     174                 :            :      or a zero-length string?  We test for both...  */
     175   [ +  +  +  - ]:         12 :   while (nl->n_name != NULL && nl->n_name[0] != '\0')
     176                 :            :     {
     177                 :         10 :       struct hashentry search;
     178                 :         10 :       const struct hashentry *found;
     179                 :            : 
     180                 :            :       /* Search for a matching entry in the hash table.  */
     181                 :         10 :       search.str = nl->n_name;
     182                 :         10 :       found = nlist_fshash_find (table, nl->n_name, 0, &search);
     183                 :            : 
     184         [ +  + ]:         10 :       if (found != NULL)
     185                 :            :         {
     186                 :            :           /* Found it.  */
     187                 :          8 :           nl->n_value = found->sym.st_value;
     188                 :          8 :           nl->n_scnum = found->sym.st_shndx;
     189                 :          8 :           nl->n_type = GELF_ST_TYPE (found->sym.st_info);
     190                 :            :           /* XXX What shall we fill in the next fields?  */
     191                 :          8 :           nl->n_sclass = 0;
     192                 :          8 :           nl->n_numaux = 0;
     193                 :            :         }
     194                 :            :       else
     195                 :            :         {
     196                 :            :           /* Not there.  */
     197                 :          2 :           nl->n_value = 0;
     198                 :          2 :           nl->n_scnum = 0;
     199                 :          2 :           nl->n_type = 0;
     200                 :          2 :           nl->n_sclass = 0;
     201                 :          2 :           nl->n_numaux = 0;
     202                 :            :         }
     203                 :            : 
     204                 :            :       /* Next search request.  */
     205                 :         10 :       ++nl;
     206                 :            :     }
     207                 :            : 
     208                 :            :   /* Free the resources.  */
     209                 :          2 :   nlist_fshash_fini (table);
     210                 :            : 
     211                 :            :   /* We do not need the ELF descriptor anymore.  */
     212                 :          2 :   (void) INTUSE(elf_end) (elf);
     213                 :            : 
     214                 :            :   /* Neither the file descriptor.  */
     215                 :          2 :   (void) close (fd);
     216                 :            : 
     217                 :          2 :   return 0;
     218                 :            : 
     219                 :          0 :  fail_dealloc:
     220                 :          0 :   nlist_fshash_fini (table);
     221                 :            : 
     222                 :          0 :  fail_close:
     223                 :            :   /* We do not need the ELF descriptor anymore.  */
     224                 :          0 :   (void) INTUSE(elf_end) (elf);
     225                 :            : 
     226                 :          0 :  fail_fd:
     227                 :            :   /* Neither the file descriptor.  */
     228                 :          0 :   (void) close (fd);
     229                 :            : 
     230                 :            :  fail:
     231                 :            :   /* We have to set all entries to zero.  */
     232   [ +  +  +  - ]:         12 :   while (nl->n_name != NULL && nl->n_name[0] != '\0')
     233                 :            :     {
     234                 :         10 :       nl->n_value = 0;
     235                 :         10 :       nl->n_scnum = 0;
     236                 :         10 :       nl->n_type = 0;
     237                 :         10 :       nl->n_sclass = 0;
     238                 :         10 :       nl->n_numaux = 0;
     239                 :            : 
     240                 :            :       /* Next entry.  */
     241                 :         10 :       ++nl;
     242                 :            :     }
     243                 :            : 
     244                 :            :   return -1;
     245                 :            : }

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