sysdeps/unix/nlist.c

   1 /* Copyright (C) 1991 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 <ansidecl.h>
  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 DEFUN(nlist, (file, nl),
  31       CONST char *file AND 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       errno = EINVAL;
  44       return -1;
  45     }
  46
  47   f = fopen(file, "r");
  48   if (f == NULL)
  49     return -1;
  50
  51   if (fread((PTR) &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((PTR) symbols, sizeof(symbols[0]), nsymbols, f) != nsymbols)
  61     goto lose;
  62
  63   if (fread((PTR) &string_table_size, sizeof(string_table_size), 1, f) != 1)
  64     goto lose;
  65   string_table_size -= sizeof(string_table_size);
  66
  67   string_table = (char *) __alloca(string_table_size);
  68   if (fread((PTR) 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 }