00001 // Copyright (c) 2005, Google Inc. 00002 // All rights reserved. 00003 // 00004 // Redistribution and use in source and binary forms, with or without 00005 // modification, are permitted provided that the following conditions are 00006 // met: 00007 // 00008 // * Redistributions of source code must retain the above copyright 00009 // notice, this list of conditions and the following disclaimer. 00010 // * Redistributions in binary form must reproduce the above 00011 // copyright notice, this list of conditions and the following disclaimer 00012 // in the documentation and/or other materials provided with the 00013 // distribution. 00014 // * Neither the name of Google Inc. nor the names of its 00015 // contributors may be used to endorse or promote products derived from 00016 // this software without specific prior written permission. 00017 // 00018 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 00019 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 00020 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 00021 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 00022 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 00023 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 00024 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 00025 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 00026 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 00027 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 00028 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 00029 00030 // --- 00031 // Author: Arun Sharma 00032 // 00033 // Produce stack trace using libunwind 00034 00035 extern "C" { 00036 #include <assert.h> 00037 #include <libunwind.h> 00038 } 00039 #include "google/stacktrace.h" 00040 #include "base/spinlock.h" 00041 00042 // Sometimes, we can try to get a stack trace from within a stack 00043 // trace, because libunwind can call mmap/sbrk (maybe indirectly via 00044 // malloc), and that mmap gets trapped and causes a stack-trace 00045 // request. If were to try to honor that recursive request, we'd end 00046 // up with infinite recursion or deadlock. Luckily, it's safe to 00047 // ignore those subsequent traces. In such cases, we return 0 to 00048 // indicate the situation. 00049 static SpinLock libunwind_lock(SpinLock::LINKER_INITIALIZED); 00050 static bool in_get_stack_trace = false; 00051 00052 int GetStackTrace(void** result, int max_depth, int skip_count) { 00053 void *ip; 00054 int n = 0; 00055 unw_cursor_t cursor; 00056 unw_context_t uc; 00057 00058 { 00059 SpinLockHolder sh(&libunwind_lock); 00060 if (in_get_stack_trace) { 00061 return 0; 00062 } else { 00063 in_get_stack_trace = true; 00064 } 00065 } 00066 00067 unw_getcontext(&uc); 00068 int ret = unw_init_local(&cursor, &uc); 00069 assert(ret >= 0); 00070 skip_count++; // Do not include the "GetStackTrace" frame 00071 00072 while (n < max_depth) { 00073 int ret = unw_get_reg(&cursor, UNW_REG_IP, (unw_word_t *) &ip); 00074 if (ret < 0) 00075 break; 00076 if (skip_count > 0) { 00077 skip_count--; 00078 } else { 00079 result[n++] = ip; 00080 } 00081 ret = unw_step(&cursor); 00082 if (ret <= 0) 00083 break; 00084 } 00085 00086 SpinLockHolder sh(&libunwind_lock); 00087 in_get_stack_trace = false; 00088 00089 return n; 00090 }