1 /*
   2  * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 
  27 #if !defined(_WINDOWS) && !defined(__APPLE__)
  28 
  29 #include "memory/allocation.inline.hpp"
  30 #include "utilities/elfFuncDescTable.hpp"
  31 #include "utilities/elfSymbolTable.hpp"
  32 
  33 ElfSymbolTable::ElfSymbolTable(FILE* file, Elf_Shdr shdr) {
  34   assert(file, "null file handle");
  35   m_symbols = NULL;
  36   m_next = NULL;
  37   m_file = file;
  38   m_status = NullDecoder::no_error;
  39 
  40   // try to load the string table
  41   long cur_offset = ftell(file);
  42   if (cur_offset != -1) {
  43     // call malloc so we can back up if memory allocation fails.
  44     m_symbols = (Elf_Sym*)os::malloc(shdr.sh_size, mtInternal);
  45     if (m_symbols) {
  46       if (fseek(file, shdr.sh_offset, SEEK_SET) ||
  47         fread((void*)m_symbols, shdr.sh_size, 1, file) != 1 ||
  48         fseek(file, cur_offset, SEEK_SET)) {
  49         m_status = NullDecoder::file_invalid;
  50         os::free(m_symbols);
  51         m_symbols = NULL;
  52       }
  53     }
  54     if (!NullDecoder::is_error(m_status)) {
  55       memcpy(&m_shdr, &shdr, sizeof(Elf_Shdr));
  56     }
  57   } else {
  58     m_status = NullDecoder::file_invalid;
  59   }
  60 }
  61 
  62 ElfSymbolTable::~ElfSymbolTable() {
  63   if (m_symbols != NULL) {
  64     os::free(m_symbols);
  65   }
  66 
  67   if (m_next != NULL) {
  68     delete m_next;
  69   }
  70 }
  71 
  72 bool ElfSymbolTable::compare(const Elf_Sym* sym, address addr, int* stringtableIndex, int* posIndex, int* offset, ElfFuncDescTable* funcDescTable) {
  73   if (STT_FUNC == ELF_ST_TYPE(sym->st_info)) {
  74     Elf_Word st_size = sym->st_size;
  75     address sym_addr;
  76     if (funcDescTable != NULL && funcDescTable->get_index() == sym->st_shndx) {
  77       // We need to go another step trough the function descriptor table (currently PPC64 only)
  78       sym_addr = funcDescTable->lookup(sym->st_value);
  79     } else {
  80       sym_addr = (address)sym->st_value;
  81     }
  82     if (sym_addr <= addr && (Elf_Word)(addr - sym_addr) < st_size) {
  83       *offset = (int)(addr - sym_addr);
  84       *posIndex = sym->st_name;
  85       *stringtableIndex = m_shdr.sh_link;
  86       return true;
  87     }
  88   }
  89   return false;
  90 }
  91 
  92 bool ElfSymbolTable::lookup(address addr, int* stringtableIndex, int* posIndex, int* offset, ElfFuncDescTable* funcDescTable) {
  93   assert(stringtableIndex, "null string table index pointer");
  94   assert(posIndex, "null string table offset pointer");
  95   assert(offset, "null offset pointer");
  96 
  97   if (NullDecoder::is_error(m_status)) {
  98     return false;
  99   }
 100 
 101   size_t  sym_size = sizeof(Elf_Sym);
 102   assert((m_shdr.sh_size % sym_size) == 0, "check size");
 103   int count = m_shdr.sh_size / sym_size;
 104   if (m_symbols != NULL) {
 105     for (int index = 0; index < count; index ++) {
 106       if (compare(&m_symbols[index], addr, stringtableIndex, posIndex, offset, funcDescTable)) {
 107         return true;
 108       }
 109     }
 110   } else {
 111     long cur_pos;
 112     if ((cur_pos = ftell(m_file)) == -1 ||
 113       fseek(m_file, m_shdr.sh_offset, SEEK_SET)) {
 114       m_status = NullDecoder::file_invalid;
 115       return false;
 116     }
 117 
 118     Elf_Sym sym;
 119     for (int index = 0; index < count; index ++) {
 120       if (fread(&sym, sym_size, 1, m_file) == 1) {
 121         if (compare(&sym, addr, stringtableIndex, posIndex, offset, funcDescTable)) {
 122           return true;
 123         }
 124       } else {
 125         m_status = NullDecoder::file_invalid;
 126         return false;
 127       }
 128     }
 129     fseek(m_file, cur_pos, SEEK_SET);
 130   }
 131   return false;
 132 }
 133 
 134 #endif // !_WINDOWS && !__APPLE__