sysdeps/unix/nlist.c

   1 /* Copyright (C) 1991, 1996 Free Software Foundation, Inc.
   2 This file is part of the GNU C Library.
   3
   4 The GNU C Library is free software; you can redistribute it and/or modify
   5 it under the terms of the GNU General Public License as published by
   6 the Free Software Foundation; either version 2, or (at your option)
   7 any later version.
   8
   9 The GNU C Library is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 GNU General Public License for more details.
  13
  14 You should have received a copy of the GNU General Public License
  15 along with the GNU C Library; see the file COPYING.  If not, write to
  16 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  17
  18 #include <errno.h>
  19 #include <a.out.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23
  24
  25 /* Search the executable FILE for symbols matching those in NL,
  26    which is terminated by an element with a NULL `n_un.n_name' member,
  27    and fill in the elements of NL.  */
  28 int
  29 nlist (file, nl)
  30      const char *file;
  31      struct nlist *nl;
  32 {
  33   FILE *f;
  34   struct exec header;
  35   size_t nsymbols;
  36   struct nlist *symbols;
  37   unsigned long int string_table_size;
  38   char *string_table;
  39   register size_t i;
  40
  41   if (nl == NULL)
  42     {
  43       __set_errno (EINVAL);
  44       return -1;
  45     }
  46
  47   f = fopen (file, "r");
  48   if (f == NULL)
  49     return -1;
  50
  51   if (fread ((void *) &header, sizeof (header), 1, f) != 1)
  52     goto lose;
  53
  54   if (fseek (f, N_SYMOFF (header), SEEK_SET) != 0)
  55     goto lose;
  56
  57   symbols = (struct nlist *) __alloca (header.a_syms);
  58   nsymbols = header.a_syms / sizeof (symbols[0]);
  59
  60   if (fread ((void *) symbols, sizeof (symbols[0]), nsymbols, f) != nsymbols)
  61     goto lose;
  62
  63   if (fread ((void *) &string_table_size, sizeof (string_table_size), 1, f)
  64       != 1)
  65     goto lose;
  66   string_table_size -= sizeof (string_table_size);
  67
  68   string_table = (char *) __alloca (string_table_size);
  69   if (fread ((void *) string_table, string_table_size, 1, f) != 1)
  70     goto lose;
  71
  72   for (i = 0; i < nsymbols; ++i)
  73     {
  74       register struct nlist *nlp;
  75       for (nlp = nl; nlp->n_un.n_name != NULL; ++nlp)
  76         if (!strcmp (nlp->n_un.n_name,
  77                      &string_table[symbols[i].n_un.n_strx -
  78                                   sizeof (string_table_size)]))
  79           {
  80             char *const name = nlp->n_un.n_name;
  81             *nlp = symbols[i];
  82             nlp->n_un.n_name = name;
  83           }
  84     }
  85
  86   (void) fclose (f);
  87   return 0;
  88
  89  lose:;
  90   (void) fclose (f);
  91   return -1;
  92 }