Fork breakpad's dump_syms and related code. Generate XOR of first page of mem...

breakpad/linux/file_id.cc

+// Copyright (c) 2006, 2009, 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.
+//
+// file_id.cc: Return a unique identifier for a file
+//
+// See file_id.h for documentation
+//
+
+#include "breakpad/linux/file_id.h"
+
+#include <elf.h>
+#include <fcntl.h>
+#include <link.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
+#include <cassert>
+#include <cstdio>
+
+namespace google_breakpad {
+
+FileID::FileID(const char* path) {
+  strncpy(path_, path, sizeof(path_));
+}
+
+bool FileID::ElfFileIdentifier(uint8_t identifier[kMDGUIDSize]) {
+  const size_t mapped_len = 4096;  // Page size (matches WriteMappings())
+  int fd = open(path_, O_RDONLY);
+  if (fd < 0)
+    return false;
+  struct stat st;
+  if (fstat(fd, &st) != 0 || st.st_size <= mapped_len) {
+    close(fd);
+    return false;
+  }
+  void* base = mmap(NULL, mapped_len,
+                    PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
+  close(fd);
+  if (base == MAP_FAILED)
+    return false;
+
+  memset(identifier, 0, kMDGUIDSize);
+  uint8_t* ptr = reinterpret_cast<uint8_t*>(base);
+  uint8_t* ptr_end = ptr + mapped_len;
+  while (ptr < ptr_end) {
+    for (unsigned i = 0; i < kMDGUIDSize; i++)
+      identifier[i] ^= ptr[i];
+    ptr += kMDGUIDSize;
+  }
+
+  munmap(base, mapped_len);
+  return true;
+}
+
+// static
+void FileID::ConvertIdentifierToString(const uint8_t identifier[kMDGUIDSize],
+                                       char* buffer, int buffer_length) {
+  int buffer_idx = 0;
+  for (int idx = 0;
+       (buffer_idx < buffer_length) && (idx < kMDGUIDSize);
+       ++idx) {
+    int hi = (identifier[idx] >> 4) & 0x0F;
+    int lo = (identifier[idx]) & 0x0F;
+
+    if (idx == 4 || idx == 6 || idx == 8 || idx == 10)
+      buffer[buffer_idx++] = '-';
+
+    buffer[buffer_idx++] = (hi >= 10) ? 'A' + hi - 10 : '0' + hi;
+    buffer[buffer_idx++] = (lo >= 10) ? 'A' + lo - 10 : '0' + lo;
+  }
+
+  // NULL terminate
+  buffer[(buffer_idx < buffer_length) ? buffer_idx : buffer_idx - 1] = 0;
+}
+
+}  // namespace google_breakpad