sysdeps/unix/nlist.c

   1 /* Copyright (C) 1991, 1996, 1997 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
   5    modify it under the terms of the GNU Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    License, or (at your option) 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 GNU
  12    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #include <errno.h>
  20 #include <a.out.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24
  25
  26 /* Search the executable FILE for symbols matching those in NL,
  27    which is terminated by an element with a NULL `n_un.n_name' member,
  28    and fill in the elements of NL.  */
  29 int
  30 nlist (const char *file, struct nlist *nl)
  31 {
  32   FILE *f;
  33   struct exec header;
  34   size_t nsymbols;
  35   struct nlist *symbols;
  36   unsigned long int string_table_size;
  37   char *string_table;
  38   register size_t i;
  39
  40   if (nl == NULL)
  41     {
  42       __set_errno (EINVAL);
  43       return -1;
  44     }
  45
  46   f = fopen (file, "r");
  47   if (f == NULL)
  48     return -1;
  49
  50   if (fread ((void *) &header, sizeof (header), 1, f) != 1)
  51     goto lose;
  52
  53   if (fseek (f, N_SYMOFF (header), SEEK_SET) != 0)
  54     goto lose;
  55
  56   symbols = (struct nlist *) __alloca (header.a_syms);
  57   nsymbols = header.a_syms / sizeof (symbols[0]);
  58
  59   if (fread ((void *) symbols, sizeof (symbols[0]), nsymbols, f) != nsymbols)
  60     goto lose;
  61
  62   if (fread ((void *) &string_table_size, sizeof (string_table_size), 1, f)
  63       != 1)
  64     goto lose;
  65   string_table_size -= sizeof (string_table_size);
  66
  67   string_table = (char *) __alloca (string_table_size);
  68   if (fread ((void *) string_table, string_table_size, 1, f) != 1)
  69     goto lose;
  70
  71   for (i = 0; i < nsymbols; ++i)
  72     {
  73       register struct nlist *nlp;
  74       for (nlp = nl; nlp->n_un.n_name != NULL; ++nlp)
  75         if (!strcmp (nlp->n_un.n_name,
  76                      &string_table[symbols[i].n_un.n_strx -
  77                                   sizeof (string_table_size)]))
  78           {
  79             char *const name = nlp->n_un.n_name;
  80             *nlp = symbols[i];
  81             nlp->n_un.n_name = name;
  82           }
  83     }
  84
  85   (void) fclose (f);
  86   return 0;
  87
  88  lose:;
  89   (void) fclose (f);
  90   return -1;
  91 }