Add utilities for processing Linux core dump files.

This patch is part of a bigger patch that helps merging the breakpad code
with the modified version in Chromium OS.

Specifically, this patch makes the following changes:
1. Add an ElfCoreDump class for processing Linux core dump files, which will
   later be used to implement the core dump to minidump conversion.
2. Add a CrashGenerator class for generating a crash with a core dump file
   for testing the functionalities of ElfCoreDump.
3. Move some utility functions for reading/writing files to file_utils.h.

BUG=455
TEST=Tested the following:
1. Build on 32-bit and 64-bit Linux with gcc 4.4.3 and gcc 4.6.
2. Build on Mac OS X 10.6.8 with gcc 4.2 and clang 3.0 (with latest gmock).
3. All unit tests pass.
Review URL: http://breakpad.appspot.com/337001

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@900 4c0a9323-5329-0410-9bdc-e9ce6186880e

1 files changed, 179 insertions, 0 deletions

diff --git a/src/common/linux/elf_core_dump.cc b/src/common/linux/elf_core_dump.cc
new file mode 100644
index 00000000..0e7db7b1
--- /dev/null
+++ b/src/common/linux/elf_core_dump.cc
@@ -0,0 +1,179 @@
+// Copyright (c) 2011, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// elf_core_dump.cc: Implement google_breakpad::ElfCoreDump.
+// See elf_core_dump.h for details.
+
+#include "common/linux/elf_core_dump.h"
+
+#include <stddef.h>
+#include <string.h>
+
+namespace google_breakpad {
+
+// Implementation of ElfCoreDump::Note.
+
+ElfCoreDump::Note::Note() {}
+
+ElfCoreDump::Note::Note(const MemoryRange& content) : content_(content) {}
+
+bool ElfCoreDump::Note::IsValid() const {
+  return GetHeader() != NULL;
+}
+
+const ElfCoreDump::Nhdr* ElfCoreDump::Note::GetHeader() const {
+  return content_.GetData<Nhdr>(0);
+}
+
+ElfCoreDump::Word ElfCoreDump::Note::GetType() const {
+  const Nhdr* header = GetHeader();
+  // 0 is not being used as a NOTE type.
+  return header ? header->n_type : 0;
+}
+
+MemoryRange ElfCoreDump::Note::GetName() const {
+  const Nhdr* header = GetHeader();
+  if (header) {
+      return content_.Subrange(sizeof(Nhdr), header->n_namesz);
+  }
+  return MemoryRange();
+}
+
+MemoryRange ElfCoreDump::Note::GetDescription() const {
+  const Nhdr* header = GetHeader();
+  if (header) {
+    return content_.Subrange(AlignedSize(sizeof(Nhdr) + header->n_namesz),
+                             header->n_descsz);
+  }
+  return MemoryRange();
+}
+
+ElfCoreDump::Note ElfCoreDump::Note::GetNextNote() const {
+  MemoryRange next_content;
+  const Nhdr* header = GetHeader();
+  if (header) {
+    size_t next_offset = AlignedSize(sizeof(Nhdr) + header->n_namesz);
+    next_offset = AlignedSize(next_offset + header->n_descsz);
+    next_content =
+        content_.Subrange(next_offset, content_.length() - next_offset);
+  }
+  return Note(next_content);
+}
+
+// static
+size_t ElfCoreDump::Note::AlignedSize(size_t size) {
+  size_t mask = sizeof(Word) - 1;
+  return (size + mask) & ~mask;
+}
+
+
+// Implementation of ElfCoreDump.
+
+ElfCoreDump::ElfCoreDump() {}
+
+ElfCoreDump::ElfCoreDump(const MemoryRange& content)
+    : content_(content) {
+}
+
+void ElfCoreDump::SetContent(const MemoryRange& content) {
+  content_ = content;
+}
+
+bool ElfCoreDump::IsValid() const {
+  const Ehdr* header = GetHeader();
+  return (header &&
+          header->e_ident[0] == ELFMAG0 &&
+          header->e_ident[1] == ELFMAG1 &&
+          header->e_ident[2] == ELFMAG2 &&
+          header->e_ident[3] == ELFMAG3 &&
+          header->e_ident[4] == kClass &&
+          header->e_version == EV_CURRENT &&
+          header->e_type == ET_CORE);
+}
+
+const ElfCoreDump::Ehdr* ElfCoreDump::GetHeader() const {
+  return content_.GetData<Ehdr>(0);
+}
+
+const ElfCoreDump::Phdr* ElfCoreDump::GetProgramHeader(unsigned index) const {
+  const Ehdr* header = GetHeader();
+  if (header) {
+    return reinterpret_cast<const Phdr*>(content_.GetArrayElement(
+        header->e_phoff, header->e_phentsize, index));
+  }
+  return NULL;
+}
+
+const ElfCoreDump::Phdr* ElfCoreDump::GetFirstProgramHeaderOfType(
+    Word type) const {
+  for (unsigned i = 0, n = GetProgramHeaderCount(); i < n; ++i) {
+    const Phdr* program = GetProgramHeader(i);
+    if (program->p_type == type) {
+      return program;
+    }
+  }
+  return NULL;
+}
+
+unsigned ElfCoreDump::GetProgramHeaderCount() const {
+  const Ehdr* header = GetHeader();
+  return header ? header->e_phnum : 0;
+}
+
+bool ElfCoreDump::CopyData(void* buffer, Addr virtual_address, size_t length) {
+  for (unsigned i = 0, n = GetProgramHeaderCount(); i < n; ++i) {
+    const Phdr* program = GetProgramHeader(i);
+    if (program->p_type != PT_LOAD)
+      continue;
+
+    size_t offset_in_segment = virtual_address - program->p_vaddr;
+    if (virtual_address >= program->p_vaddr &&
+        offset_in_segment < program->p_filesz) {
+      const void* data =
+          content_.GetData(program->p_offset + offset_in_segment, length);
+      if (data) {
+        memcpy(buffer, data, length);
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
+ElfCoreDump::Note ElfCoreDump::GetFirstNote() const {
+  MemoryRange note_content;
+  const Phdr* program_header = GetFirstProgramHeaderOfType(PT_NOTE);
+  if (program_header) {
+    note_content = content_.Subrange(program_header->p_offset,
+                                     program_header->p_filesz);
+  }
+  return Note(note_content);
+}
+
+}  // namespace google_breakpad