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      1 /*
      2  * Copyright (C) 2015 The Android Open Source Project
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      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 copyright
     11  *    notice, this list of conditions and the following disclaimer in
     12  *    the documentation and/or other materials provided with the
     13  *    distribution.
     14  *
     15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     16  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     17  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
     18  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
     19  * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     21  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
     22  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     23  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     24  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
     25  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 
     29 #include <errno.h>
     30 #include <signal.h>
     31 #include <stdint.h>
     32 #include <stdlib.h>
     33 #include <sys/types.h>
     34 #include <unistd.h>
     35 
     36 #include <private/bionic_macros.h>
     37 
     38 #include "BacktraceData.h"
     39 #include "Config.h"
     40 #include "DebugData.h"
     41 #include "debug_log.h"
     42 #include "malloc_debug.h"
     43 
     44 BacktraceData::BacktraceData(const Config& config, size_t* offset) {
     45   size_t hdr_len = sizeof(BacktraceHeader) + sizeof(uintptr_t) * config.backtrace_frames;
     46   alloc_offset_ = *offset;
     47   *offset += BIONIC_ALIGN(hdr_len, MINIMUM_ALIGNMENT_BYTES);
     48 }
     49 
     50 static BacktraceData* g_backtrace_data = nullptr;
     51 
     52 static void EnableToggle(int, siginfo_t*, void*) {
     53   if (g_backtrace_data->enabled()) {
     54     g_backtrace_data->set_enabled(false);
     55   } else {
     56     g_backtrace_data->set_enabled(true);
     57   }
     58 }
     59 
     60 bool BacktraceData::Initialize(const Config& config) {
     61   enabled_ = config.backtrace_enabled;
     62   if (config.backtrace_enable_on_signal) {
     63     g_backtrace_data = this;
     64 
     65     struct sigaction enable_act;
     66     memset(&enable_act, 0, sizeof(enable_act));
     67 
     68     enable_act.sa_sigaction = EnableToggle;
     69     enable_act.sa_flags = SA_RESTART | SA_SIGINFO | SA_ONSTACK;
     70     sigemptyset(&enable_act.sa_mask);
     71     if (sigaction(config.backtrace_signal, &enable_act, nullptr) != 0) {
     72       error_log("Unable to set up backtrace signal enable function: %s", strerror(errno));
     73       return false;
     74     }
     75     info_log("%s: Run: 'kill -%d %d' to enable backtracing.", getprogname(),
     76              config.backtrace_signal, getpid());
     77   }
     78   return true;
     79 }
     80