Make debug_util cross platform, adding BeingDebugged and BreakDebugger. Linux

supported added, and Mac OSX left as a todo for the mac team.


git-svn-id: svn://svn.chromium.org/chrome/trunk/src@785 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 90 insertions, 0 deletions

diff --git a/base/debug_util_posix.cc b/base/debug_util_posix.cc
new file mode 100644
index 0000000..84b5aae
--- /dev/null
+++ b/base/debug_util_posix.cc
@@ -0,0 +1,90 @@
+// Copyright 2008, 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.
+
+#include "base/debug_util.h"
+
+#include <unistd.h>
+#include <sys/sysctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+#include "base/notimplemented.h"
+#include "base/string_piece.h"
+
+bool DebugUtil::SpawnDebuggerOnProcess(unsigned /* process_id */) {
+  NOTIMPLEMENTED();
+  return false;
+}
+
+#if defined(OS_MACOSX)
+// http://developer.apple.com/qa/qa2004/qa1361.html
+bool DebugUtil::BeingDebugged() {
+  NOTIMPLEMENTED();
+  return false;
+}
+
+#elif defined(OS_LINUX)
+// We can look in /proc/self/status for TracerPid.  We are likely used in crash
+// handling, so we are careful not to use the heap or have side effects.
+// Another option that is common is to try to ptrace yourself, but then we
+// can't detach without forking(), and that's not so great.
+bool DebugUtil::BeingDebugged() {
+  int status_fd = open("/proc/self/status", O_RDONLY);
+  if (status_fd == -1)
+    return false;
+
+  // We assume our line will be in the first 1024 characters and that we can
+  // read this much all at once.  In practice this will generally be true.
+  // This simplifies and speeds up things considerably.
+  char buf[1024];
+
+  ssize_t num_read = read(status_fd, buf, sizeof(buf));
+  close(status_fd);
+
+  if (num_read <= 0)
+    return false;
+
+  StringPiece status(buf, num_read);
+  StringPiece tracer("TracerPid:\t");
+
+  StringPiece::size_type pid_index = status.find(tracer);
+  if (pid_index == StringPiece::npos)
+    return false;
+
+  // Our pid is 0 without a debugger, assume this for any pid starting with 0.
+  pid_index += tracer.size();
+  return pid_index < status.size() && status[pid_index] != '0';
+}
+#endif
+
+// static
+void DebugUtil::BreakDebugger() {
+  asm ("int3");
+}