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 <afsconfig.h>
  14 #include <afs/param.h>
  15
  16
  17 #include "sys/types.h"
  18 #include "sym.h"
  19
  20 /*
  21  * using the toc_syment structure, that we fabricate:
  22  *      sym->n_offset is the string pointer
  23  */
  24 #ifdef __XCOFF64__
  25 #define sym_str(sym) ((char *) (sym)->n_nptr)
  26 #else
  27 #define sym_off(sym)    ((sym)->n_offset)
  28 #define sym_str(sym)    \
  29         ((sym)->n_zeroes == 0 ? (char *) sym_off(sym) : (sym)->n_name)
  30 #endif
  31
  32 sym_t *
  33 sym_lookup(name, value)
  34      char *name;
  35 {
  36     static sym_t *symsrch(), *search();
  37     char buf[64];
  38     sym_t *sym;
  39
  40     if (name) {
  41         /*
  42          * Heuristic:
  43          * first, try just the name. if that fails, try with a
  44          * prefix '.', and failing that, a prefix '_'.
  45          */
  46         if (sym = symsrch(name))
  47             return sym;
  48         memcpy(buf + 1, name, sizeof(buf) - 2);
  49         buf[0] = '.';
  50
  51         if (sym = symsrch(buf))
  52             return sym;
  53
  54         buf[0] = '_';
  55
  56         return symsrch(buf);
  57     } else
  58         return search(value);
  59 }
  60
  61 static sym_t *
  62 search(addr)
  63      unsigned addr;
  64 {
  65     sym_t *sp;
  66     sym_t *save;
  67     unsigned value;
  68
  69     value = 0;
  70     save = 0;
  71
  72     for (sp = toc_syms; sp < &toc_syms[toc_nsyms]; ++sp) {
  73         if (sp->n_value <= addr && sp->n_value >= value) {
  74             value = sp->n_value;
  75             save = sp;
  76             if (sp->n_value == addr)
  77                 break;
  78         }
  79     }
  80     return save ? sym_flex(save) : 0;
  81 }
  82
  83 static sym_t *
  84 symsrch(s)
  85      char *s;
  86 {
  87     sym_t *sp;
  88     sym_t *found;
  89     int len;
  90     char *p;
  91
  92     /*
  93      * determine length of symbol
  94      */
  95     for (len = 0, p = s; *p; ++p)
  96         ++len;
  97
  98     found = 0;
  99     for (sp = toc_syms; sp < &toc_syms[toc_nsyms]; ++sp) {
 100         /*
 101          * exact matches preferred
 102          */
 103         if (strcmp(sym_str(sp), s) == 0) {
 104             found = sp;
 105             break;
 106         }
 107         /*
 108          * otherwise, prefices might interest us.
 109          */
 110         if (!found && (strncmp(sym_str(sp), s, len) == 0)) {
 111             found = sp;
 112             continue;
 113         }
 114     }
 115
 116     return found ? sym_flex(found) : 0;
 117 }
 118
 119 /*
 120  * sym_flex -   convert a symbol so that there is no distinction between
 121  *              flex-string and non flex-string format.
 122  *
 123  * Input:
 124  *      sym     -       ^ to symbol table entry
 125  *
 126  * Returns:
 127  *      ^ to static location containing modified symbol.
 128  */
 129 sym_t *
 130 sym_flex(sym)
 131      sym_t *sym;
 132 {
 133     static sym_t symbol;
 134     static char name[48];
 135
 136     strncpy(name, sym_str(sym), sizeof(name) - 1);
 137
 138 #ifndef __XCOFF64__
 139     if (sym->n_zeroes != 0)
 140         name[8] = 0;            /* make sure that we truncate correctly */
 141     symbol.n_zeroes = 0;
 142 #endif
 143
 144     symbol = *sym;
 145     symbol.n_nptr = name;
 146
 147     return &symbol;
 148 }