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/thirdparty/breakpad/third_party/glog/src/stacktrace_libunwind-inl.h

http://github.com/tomahawk-player/tomahawk
C++ Header | 87 lines | 37 code | 10 blank | 40 comment | 6 complexity | 35ae3ad7a6d5db570d9b8c3a2e5fbd3b MD5 | raw file
 1// Copyright (c) 2005 - 2007, Google Inc.
 2// All rights reserved.
 3//
 4// Redistribution and use in source and binary forms, with or without
 5// modification, are permitted provided that the following conditions are
 6// met:
 7//
 8//     * Redistributions of source code must retain the above copyright
 9// notice, this list of conditions and the following disclaimer.
10//     * Redistributions in binary form must reproduce the above
11// copyright notice, this list of conditions and the following disclaimer
12// in the documentation and/or other materials provided with the
13// distribution.
14//     * Neither the name of Google Inc. nor the names of its
15// contributors may be used to endorse or promote products derived from
16// this software without specific prior written permission.
17//
18// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29//
30// Author: Arun Sharma
31//
32// Produce stack trace using libunwind
33
34#include "utilities.h"
35
36extern "C" {
37#define UNW_LOCAL_ONLY
38#include <libunwind.h>
39}
40#include "glog/raw_logging.h"
41#include "stacktrace.h"
42
43_START_GOOGLE_NAMESPACE_
44
45// Sometimes, we can try to get a stack trace from within a stack
46// trace, because libunwind can call mmap (maybe indirectly via an
47// internal mmap based memory allocator), and that mmap gets trapped
48// and causes a stack-trace request.  If were to try to honor that
49// recursive request, we'd end up with infinite recursion or deadlock.
50// Luckily, it's safe to ignore those subsequent traces.  In such
51// cases, we return 0 to indicate the situation.
52static bool g_now_entering = false;
53
54// If you change this function, also change GetStackFrames below.
55int GetStackTrace(void** result, int max_depth, int skip_count) {
56  void *ip;
57  int n = 0;
58  unw_cursor_t cursor;
59  unw_context_t uc;
60
61  if (sync_val_compare_and_swap(&g_now_entering, false, true)) {
62    return 0;
63  }
64
65  unw_getcontext(&uc);
66  RAW_CHECK(unw_init_local(&cursor, &uc) >= 0, "unw_init_local failed");
67  skip_count++;         // Do not include the "GetStackTrace" frame
68
69  while (n < max_depth) {
70    int ret = unw_get_reg(&cursor, UNW_REG_IP, (unw_word_t *) &ip);
71    if (ret < 0)
72      break;
73    if (skip_count > 0) {
74      skip_count--;
75    } else {
76      result[n++] = ip;
77    }
78    ret = unw_step(&cursor);
79    if (ret <= 0)
80      break;
81  }
82
83  g_now_entering = false;
84  return n;
85}
86
87_END_GOOGLE_NAMESPACE_