tools/leaky/elf.cpp

   1 /* ***** BEGIN LICENSE BLOCK *****
   2  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   3  *
   4  * The contents of this file are subject to the Mozilla Public License Version
   5  * 1.1 (the "License"); you may not use this file except in compliance with
   6  * the License. You may obtain a copy of the License at
   7  * http://www.mozilla.org/MPL/
   8  *
   9  * Software distributed under the License is distributed on an "AS IS" basis,
  10  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  11  * for the specific language governing rights and limitations under the
  12  * License.
  13  *
  14  * The Original Code is mozilla.org code.
  15  *
  16  * The Initial Developer of the Original Code is
  17  * Kipp E.B. Hickman.
  18  * Portions created by the Initial Developer are Copyright (C) 1999
  19  * the Initial Developer. All Rights Reserved.
  20  *
  21  * Contributor(s):
  22  *
  23  * Alternatively, the contents of this file may be used under the terms of
  24  * either the GNU General Public License Version 2 or later (the "GPL"), or
  25  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  26  * in which case the provisions of the GPL or the LGPL are applicable instead
  27  * of those above. If you wish to allow use of your version of this file only
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  32  * the provisions above, a recipient may use your version of this file under
  33  * the terms of any one of the MPL, the GPL or the LGPL.
  34  *
  35  * ***** END LICENSE BLOCK ***** */
  36
  37 #include "leaky.h"
  38
  39 #ifdef USE_ELF
  40
  41 #include "leaky.h"
  42 #include <stdio.h>
  43 #include <malloc.h>
  44 #include <libelf/libelf.h>
  45 #include <unistd.h>
  46 #include <fcntl.h>
  47 #include <string.h>
  48
  49 void leaky::readSymbols(const char *fileName)
  50 {
  51     int fd = ::open(fileName, O_RDONLY);
  52     if (fd < 0) {
  53         fprintf(stderr, "%s: unable to open \"%s\"\n", applicationName,
  54                 fileName);
  55         exit(-1);
  56     }
  57
  58     elf_version(EV_CURRENT);
  59     Elf *elf = elf_begin(fd, ELF_C_READ, 0);
  60     if (!elf) {
  61         fprintf(stderr, "%s: \"%s\": has no symbol table\n", applicationName,
  62                 fileName);
  63         exit(-1);
  64     }
  65
  66     long alloced = 10000;
  67     Symbol* syms = (Symbol*) malloc(sizeof(Symbol) * 10000);
  68     Symbol* sp = syms;
  69     Symbol* last = syms + alloced;
  70
  71     // Get each of the relevant sections and add them to the list of
  72     // symbols.
  73     Elf32_Ehdr *ehdr = elf32_getehdr(elf);
  74     if (!ehdr) {
  75         fprintf(stderr, "%s: elf library lossage\n", applicationName);
  76         exit(-1);
  77     }
  78 #if 0
  79     Elf32_Half ndx = ehdr->e_shstrndx;
  80 #endif
  81
  82     Elf_Scn *scn = 0;
  83     int strtabndx = -1;
  84     for (int i = 1; (scn = elf_nextscn(elf, scn)) != 0; i++) {
  85         Elf32_Shdr *shdr = elf32_getshdr(scn);
  86 #if 0
  87         char *name = elf_strptr(elf, ndx, (size_t) shdr->sh_name);
  88         printf("Section %s (%d 0x%x)\n", name ? name : "(null)",
  89                shdr->sh_type, shdr->sh_type);
  90 #endif
  91         if (shdr->sh_type == SHT_STRTAB) {
  92             /* We assume here that string tables preceed symbol tables... */
  93             strtabndx = i;
  94             continue;
  95         }
  96 #if 0
  97         if (shdr->sh_type == SHT_DYNAMIC) {
  98             /* Dynamic */
  99             Elf_Data *data = elf_getdata(scn, 0);
 100             if (!data || !data->d_size) {
 101                 printf("No data...");
 102                 continue;
 103             }
 104
 105             Elf32_Dyn *dyn = (Elf32_Dyn*) data->d_buf;
 106             Elf32_Dyn *lastdyn =
 107                 (Elf32_Dyn*) ((char*) data->d_buf + data->d_size);
 108             for (; dyn < lastdyn; dyn++) {
 109                 printf("tag=%d value=0x%x\n", dyn->d_tag, dyn->d_un.d_val);
 110             }
 111         } else
 112 #endif
 113         if ((shdr->sh_type == SHT_SYMTAB) ||
 114             (shdr->sh_type == SHT_DYNSYM)) {
 115             /* Symbol table */
 116             Elf_Data *data = elf_getdata(scn, 0);
 117             if (!data || !data->d_size) {
 118                 printf("No data...");
 119                 continue;
 120             }
 121
 122             /* In theory we now have the symbols... */
 123             Elf32_Sym *esym = (Elf32_Sym*) data->d_buf;
 124             Elf32_Sym *lastsym =
 125                 (Elf32_Sym*) ((char*) data->d_buf + data->d_size);
 126             for (; esym < lastsym; esym++) {
 127 #if 0
 128                 char *nm = elf_strptr(elf, strtabndx, (size_t)esym->st_name);
 129                 printf("%20s 0x%08x %02x %02x\n",
 130                        nm, esym->st_value, ELF32_ST_BIND(esym->st_info),
 131                        ELF32_ST_TYPE(esym->st_info));
 132 #endif
 133                 if ((esym->st_value == 0) ||
 134                     (ELF32_ST_BIND(esym->st_info) == STB_WEAK) ||
 135                     (ELF32_ST_BIND(esym->st_info) == STB_NUM) ||
 136                     (ELF32_ST_TYPE(esym->st_info) != STT_FUNC)) {
 137                     continue;
 138                 }
 139 #if 1
 140                 char *nm = elf_strptr(elf, strtabndx, (size_t)esym->st_name);
 141 #endif
 142                 sp->name = nm ? strdup(nm) : "(no name)";
 143                 sp->address = esym->st_value;
 144                 sp++;
 145                 if (sp >= last) {
 146                     long n = alloced + 10000;
 147                     syms = (Symbol*)
 148                         realloc(syms, (size_t) (sizeof(Symbol) * n));
 149                     last = syms + n;
 150                     sp = syms + alloced;
 151                     alloced = n;
 152                 }
 153             }
 154         }
 155     }
 156
 157     int interesting = sp - syms;
 158     if (!quiet) {
 159         printf("Total of %d symbols\n", interesting);
 160     }
 161     usefulSymbols = interesting;
 162     externalSymbols = syms;
 163 }
 164
 165 #endif /* USE_ELF */