src/export/symtab.c

   1 /*
   2  * Copyright 2000, International Business Machines Corporation and others.
   3  * All Rights Reserved.
   4  *
   5  * This software has been released under the terms of the IBM Public
   6  * License.  For details, see the LICENSE file in the top-level source
   7  * directory or online at http://www.openafs.org/dl/license10.html
   8  */
   9
  10 /*
  11  * symtab -     symbol table routines
  12  */
  13 #include "sys/types.h"
  14 #include "sym.h"
  15
  16 /*
  17  * using the toc_syment structure, that we fabricate:
  18  *      sym->n_offset is the string pointer
  19  */
  20 #define sym_off(sym)    ((sym)->n_offset)
  21 #define sym_str(sym)    \
  22         ((sym)->n_zeroes == 0 ? (char *) sym_off(sym) : (sym)->n_name)
  23
  24 sym_t *
  25 sym_lookup(name, value)
  26 char *name; {
  27         static sym_t *symsrch(), *search();
  28         char buf[64];
  29         register sym_t *sym;
  30
  31         if (name) {
  32                 /*
  33                  * Heuristic:
  34                  * first, try just the name. if that fails, try with a
  35                  * prefix '.', and failing that, a prefix '_'.
  36                  */
  37                 if (sym = symsrch(name))
  38                         return sym;
  39                 bcopy(name, buf+1, sizeof (buf) - 2);
  40                 buf[0] = '.';
  41
  42                 if (sym = symsrch(buf))
  43                         return sym;
  44
  45                 buf[0] = '_';
  46
  47                 return symsrch(buf);
  48         } else
  49                 return search(value);
  50 }
  51
  52 static sym_t *
  53 search(addr)
  54 unsigned addr; {
  55         register sym_t *sp;
  56         register sym_t *save;
  57         unsigned value;
  58
  59         value = 0;
  60         save  = 0;
  61
  62         for (sp = toc_syms; sp < &toc_syms[toc_nsyms]; ++sp) {
  63                 if (sp->n_value <= addr && sp->n_value >= value) {
  64                         value = sp->n_value;
  65                         save  = sp;
  66                         if (sp->n_value == addr)
  67                                 break;
  68                 }
  69         }
  70         return save ? sym_flex(save) : 0;
  71 }
  72
  73 static sym_t *
  74 symsrch(s)
  75 register char *s; {
  76         register sym_t *sp;
  77         register sym_t *found;
  78         register len;
  79         register char *p;
  80
  81         /*
  82          * determine length of symbol
  83          */
  84         for (len = 0, p = s; *p; ++p)
  85                 ++len;
  86
  87         found = 0;
  88         for (sp = toc_syms; sp < &toc_syms[toc_nsyms]; ++sp) {
  89                 /*
  90                  * exact matches preferred
  91                  */
  92                 if (strcmp(sym_str(sp), s) == 0) {
  93                         found = sp;
  94                         break;
  95                 }
  96                 /*
  97                  * otherwise, prefices might interest us.
  98                  */
  99                 if (!found && (strncmp(sym_str(sp), s, len) == 0)) {
 100                         found = sp;
 101                         continue;
 102                 }
 103         }
 104
 105         return found ? sym_flex(found) : 0;
 106 }
 107
 108 /*
 109  * sym_flex -   convert a symbol so that there is no distinction between
 110  *              flex-string and non flex-string format.
 111  *
 112  * Input:
 113  *      sym     -       ^ to symbol table entry
 114  *
 115  * Returns:
 116  *      ^ to static location containing modified symbol.
 117  */
 118 sym_t *
 119 sym_flex(sym)
 120 register sym_t *sym; {
 121         static sym_t symbol;
 122         static char name[48];
 123
 124         strncpy(name, sym_str(sym), sizeof (name) - 1);
 125
 126         if (sym->n_zeroes != 0)
 127                 name[8] = 0;    /* make sure that we truncate correctly */
 128
 129         symbol          = *sym;
 130         symbol.n_zeroes = 0;
 131         symbol.n_nptr   = name;
 132
 133         return &symbol;
 134 }