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 (const char *file, struct nlist *nl)
  30 {
  31   FILE *f;
  32   struct exec header;
  33   size_t nsymbols;
  34   struct nlist *symbols;
  35   unsigned long int string_table_size;
  36   char *string_table;
  37   register size_t i;
  38
  39   if (nl == NULL)
  40     {
  41       __set_errno (EINVAL);
  42       return -1;
  43     }
  44
  45   f = fopen (file, "r");
  46   if (f == NULL)
  47     return -1;
  48
  49   if (fread ((void *) &header, sizeof (header), 1, f) != 1)
  50     goto lose;
  51
  52   if (fseek (f, N_SYMOFF (header), SEEK_SET) != 0)
  53     goto lose;
  54
  55   symbols = (struct nlist *) __alloca (header.a_syms);
  56   nsymbols = header.a_syms / sizeof (symbols[0]);
  57
  58   if (fread ((void *) symbols, sizeof (symbols[0]), nsymbols, f) != nsymbols)
  59     goto lose;
  60
  61   if (fread ((void *) &string_table_size, sizeof (string_table_size), 1, f)
  62       != 1)
  63     goto lose;
  64   string_table_size -= sizeof (string_table_size);
  65
  66   string_table = (char *) __alloca (string_table_size);
  67   if (fread ((void *) string_table, string_table_size, 1, f) != 1)
  68     goto lose;
  69
  70   for (i = 0; i < nsymbols; ++i)
  71     {
  72       register struct nlist *nlp;
  73       for (nlp = nl; nlp->n_un.n_name != NULL; ++nlp)
  74         if (!strcmp (nlp->n_un.n_name,
  75                      &string_table[symbols[i].n_un.n_strx -
  76                                   sizeof (string_table_size)]))
  77           {
  78             char *const name = nlp->n_un.n_name;
  79             *nlp = symbols[i];
  80             nlp->n_un.n_name = name;
  81           }
  82     }
  83
  84   (void) fclose (f);
  85   return 0;
  86
  87  lose:;
  88   (void) fclose (f);
  89   return -1;
  90 }