1 /*

     2  * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.

     3  * Copyright (c) 2012, 2013 SAP SE. All rights reserved.

     4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     5  *

     6  * This code is free software; you can redistribute it and/or modify it

     7  * under the terms of the GNU General Public License version 2 only, as

     8  * published by the Free Software Foundation.

     9  *

    10  * This code is distributed in the hope that it will be useful, but WITHOUT

    11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    13  * version 2 for more details (a copy is included in the LICENSE file that

    14  * accompanied this code).

    15  *

    16  * You should have received a copy of the GNU General Public License version

    17  * 2 along with this work; if not, write to the Free Software Foundation,

    18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    19  *

    20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    21  * or visit www.oracle.com if you need additional information or have any

    22  * questions.

    23  *

    24  */

    25 

    26 #include "precompiled.hpp"

    27 

    28 #if !defined(_WINDOWS) && !defined(__APPLE__)

    29 

    30 #include "memory/allocation.inline.hpp"

    31 #include "utilities/elfFuncDescTable.hpp"

    32 

    33 ElfFuncDescTable::ElfFuncDescTable(FILE* file, Elf_Shdr shdr, int index) {

    34   assert(file, "null file handle");

    35   // The actual function address (i.e. function entry point) is always the

    36   // first value in the function descriptor (on IA64 and PPC64 they look as follows):

    37   // PPC64: [function entry point, TOC pointer, environment pointer]

    38   // IA64 : [function entry point, GP (global pointer) value]

    39   // Unfortunately 'shdr.sh_entsize' doesn't always seem to contain this size (it's zero on PPC64) so we can't assert

    40   // assert(IA64_ONLY(2) PPC64_ONLY(3) * sizeof(address) == shdr.sh_entsize, "Size mismatch for '.opd' section entries");

    41 

    42   m_funcDescs = NULL;

    43   m_file = file;

    44   m_index = index;

    45   m_status = NullDecoder::no_error;

    46 

    47   // try to load the function descriptor table

    48   long cur_offset = ftell(file);

    49   if (cur_offset != -1) {

    50     // call malloc so we can back up if memory allocation fails.

    51     m_funcDescs = (address*)os::malloc(shdr.sh_size, mtInternal);

    52     if (m_funcDescs) {

    53       if (fseek(file, shdr.sh_offset, SEEK_SET) ||

    54           fread((void*)m_funcDescs, shdr.sh_size, 1, file) != 1 ||

    55           fseek(file, cur_offset, SEEK_SET)) {

    56         m_status = NullDecoder::file_invalid;

    57         os::free(m_funcDescs);

    58         m_funcDescs = NULL;

    59       }

    60     }

    61     if (!NullDecoder::is_error(m_status)) {

    62       memcpy(&m_shdr, &shdr, sizeof(Elf_Shdr));

    63     }

    64   } else {

    65     m_status = NullDecoder::file_invalid;

    66   }

    67 }

    68 

    69 ElfFuncDescTable::~ElfFuncDescTable() {

    70   if (m_funcDescs != NULL) {

    71     os::free(m_funcDescs);

    72   }

    73 }

    74 

    75 address ElfFuncDescTable::lookup(Elf_Word index) {

    76   if (NullDecoder::is_error(m_status)) {

    77     return NULL;

    78   }

    79 

    80   if (m_funcDescs != NULL) {

    81     if (m_shdr.sh_size > 0 && m_shdr.sh_addr <= index && index <= m_shdr.sh_addr + m_shdr.sh_size) {

    82       // Notice that 'index' is a byte-offset into the function descriptor table.

    83       return m_funcDescs[(index - m_shdr.sh_addr) / sizeof(address)];

    84     }

    85     return NULL;

    86   } else {

    87     long cur_pos;

    88     address addr;

    89     if (!(m_shdr.sh_size > 0 && m_shdr.sh_addr <= index && index <= m_shdr.sh_addr + m_shdr.sh_size)) {

    90       // don't put the whole decoder in error mode if we just tried a wrong index

    91       return NULL;

    92     }

    93     if ((cur_pos = ftell(m_file)) == -1 ||

    94         fseek(m_file, m_shdr.sh_offset + index - m_shdr.sh_addr, SEEK_SET) ||

    95         fread(&addr, sizeof(addr), 1, m_file) != 1 ||

    96         fseek(m_file, cur_pos, SEEK_SET)) {

    97       m_status = NullDecoder::file_invalid;

    98       return NULL;

    99     }

   100     return addr;

   101   }

   102 }

   103 

   104 #endif // !_WINDOWS && !__APPLE__