elfSymbolTable.cpp revision 2721:f08d439fab8c 
1/*
2 * Copyright (c) 1997, 2011, 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/elfSymbolTable.hpp"
31
32ElfSymbolTable::ElfSymbolTable(FILE* file, Elf_Shdr shdr) {
33  assert(file, "null file handle");
34  m_symbols = NULL;
35  m_next = NULL;
36  m_file = file;
37  m_status = Decoder::no_error;
38
39  // try to load the string table
40  long cur_offset = ftell(file);
41  if (cur_offset != -1) {
42    // call malloc so we can back up if memory allocation fails.
43    m_symbols = (Elf_Sym*)os::malloc(shdr.sh_size);
44    if (m_symbols) {
45      if (fseek(file, shdr.sh_offset, SEEK_SET) ||
46        fread((void*)m_symbols, shdr.sh_size, 1, file) != 1 ||
47        fseek(file, cur_offset, SEEK_SET)) {
48        m_status = Decoder::file_invalid;
49        os::free(m_symbols);
50        m_symbols = NULL;
51      }
52    }
53    if (m_status == Decoder::no_error) {
54      memcpy(&m_shdr, &shdr, sizeof(Elf_Shdr));
55    }
56  } else {
57    m_status = Decoder::file_invalid;
58  }
59}
60
61ElfSymbolTable::~ElfSymbolTable() {
62  if (m_symbols != NULL) {
63    os::free(m_symbols);
64  }
65
66  if (m_next != NULL) {
67    delete m_next;
68  }
69}
70
71Decoder::decoder_status ElfSymbolTable::lookup(address addr, int* stringtableIndex, int* posIndex, int* offset) {
72  assert(stringtableIndex, "null string table index pointer");
73  assert(posIndex, "null string table offset pointer");
74  assert(offset, "null offset pointer");
75
76  if (m_status != Decoder::no_error) {
77    return m_status;
78  }
79
80  address pc = 0;
81  size_t  sym_size = sizeof(Elf_Sym);
82  assert((m_shdr.sh_size % sym_size) == 0, "check size");
83  int count = m_shdr.sh_size / sym_size;
84  if (m_symbols != NULL) {
85    for (int index = 0; index < count; index ++) {
86      if (STT_FUNC == ELF_ST_TYPE(m_symbols[index].st_info)) {
87        address sym_addr = (address)m_symbols[index].st_value;
88        if (sym_addr < addr && (addr - sym_addr) < *offset) {
89          pc = (address)m_symbols[index].st_value;
90          *offset = (int)(addr - pc);
91          *posIndex = m_symbols[index].st_name;
92          *stringtableIndex = m_shdr.sh_link;
93        }
94      }
95    }
96  } else {
97    long cur_pos;
98    if ((cur_pos = ftell(m_file)) == -1 ||
99      fseek(m_file, m_shdr.sh_offset, SEEK_SET)) {
100      m_status = Decoder::file_invalid;
101      return m_status;
102    }
103
104    Elf_Sym sym;
105    for (int index = 0; index < count; index ++) {
106      if (fread(&sym, sym_size, 1, m_file) == 1) {
107        if (STT_FUNC == ELF_ST_TYPE(sym.st_info)) {
108          address sym_addr = (address)sym.st_value;
109          if (sym_addr < addr && (addr - sym_addr) < *offset) {
110            pc = (address)sym.st_value;
111            *offset = (int)(addr - pc);
112            *posIndex = sym.st_name;
113            *stringtableIndex = m_shdr.sh_link;
114          }
115        }
116      } else {
117        m_status = Decoder::file_invalid;
118        return m_status;
119      }
120    }
121    fseek(m_file, cur_pos, SEEK_SET);
122  }
123  return m_status;
124}
125
126#endif // _WINDOWS
127