libbacktrace/Backtrace.cpp - platform/system/core - Git at Google

 /*
  * Copyright (C) 2013 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include <errno.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/ptrace.h>
 #include <sys/types.h>
 #include <unistd.h>

 #define __STDC_FORMAT_MACROS
 #include <inttypes.h>

 #include <string>

 #include <backtrace/Backtrace.h>
 #include <cutils/log.h>

 #include "Backtrace.h"
 #include "thread_utils.h"

 //-------------------------------------------------------------------------
 // BacktraceImpl functions.
 //-------------------------------------------------------------------------
 backtrace_t* BacktraceImpl::GetBacktraceData() {
   return &backtrace_obj_->backtrace_;
 }

 //-------------------------------------------------------------------------
 // Backtrace functions.
 //-------------------------------------------------------------------------
 Backtrace::Backtrace(BacktraceImpl* impl) : impl_(impl), map_info_(NULL) {
   impl_->SetParent(this);
   backtrace_.num_frames = 0;
   backtrace_.pid = -1;
   backtrace_.tid = -1;
 }

 Backtrace::~Backtrace() {
   for (size_t i = 0; i < NumFrames(); i++) {
     if (backtrace_.frames[i].func_name) {
       free(backtrace_.frames[i].func_name);
       backtrace_.frames[i].func_name = NULL;
     }
   }

   if (map_info_) {
     backtrace_destroy_map_info_list(map_info_);
     map_info_ = NULL;
   }

   if (impl_) {
     delete impl_;
     impl_ = NULL;
   }
 }

 bool Backtrace::Unwind(size_t num_ignore_frames) {
   return impl_->Unwind(num_ignore_frames);
 }

 __BEGIN_DECLS
 extern char* __cxa_demangle (const char* mangled, char* buf, size_t* len,
                              int* status);
 __END_DECLS

 std::string Backtrace::GetFunctionName(uintptr_t pc, uintptr_t* offset) {
   std::string func_name = impl_->GetFunctionNameRaw(pc, offset);
   if (!func_name.empty()) {
 #if defined(__APPLE__)
     // Mac OS' __cxa_demangle demangles "f" as "float"; last tested on 10.7.
     if (symbol_name[0] != '_') {
       return func_name;
     }
 #endif
     char* name = __cxa_demangle(func_name.c_str(), 0, 0, 0);
     if (name) {
       func_name = name;
       free(name);
     }
   }
   return func_name;
 }

 bool Backtrace::VerifyReadWordArgs(uintptr_t ptr, uint32_t* out_value) {
   if (ptr & 3) {
     ALOGW("Backtrace::verifyReadWordArgs: invalid pointer %p", (void*)ptr);
     *out_value = (uint32_t)-1;
     return false;
   }
   return true;
 }

 const char* Backtrace::GetMapName(uintptr_t pc, uintptr_t* map_start) {
   const backtrace_map_info_t* map_info = FindMapInfo(pc);
   if (map_info) {
     if (map_start) {
       *map_start = map_info->start;
     }
     return map_info->name;
   }
   return NULL;
 }

 const backtrace_map_info_t* Backtrace::FindMapInfo(uintptr_t ptr) {
   return backtrace_find_map_info(map_info_, ptr);
 }

 std::string Backtrace::FormatFrameData(size_t frame_num) {
   backtrace_frame_data_t* frame = &backtrace_.frames[frame_num];
   const char* map_name;
   if (frame->map_name) {
     map_name = frame->map_name;
   } else {
     map_name = "<unknown>";
   }
   uintptr_t relative_pc;
   if (frame->map_offset) {
     relative_pc = frame->map_offset;
   } else {
     relative_pc = frame->pc;
   }

   char buf[512];
   if (frame->func_name && frame->func_offset) {
     snprintf(buf, sizeof(buf), "#%02zu pc %0*" PRIxPTR "  %s (%s+%" PRIuPTR ")",
              frame_num, (int)sizeof(uintptr_t)*2, relative_pc, map_name,
              frame->func_name, frame->func_offset);
   } else if (frame->func_name) {
     snprintf(buf, sizeof(buf), "#%02zu pc %0*" PRIxPTR "  %s (%s)", frame_num,
              (int)sizeof(uintptr_t)*2, relative_pc, map_name, frame->func_name);
   } else {
     snprintf(buf, sizeof(buf), "#%02zu pc %0*" PRIxPTR "  %s", frame_num,
              (int)sizeof(uintptr_t)*2, relative_pc, map_name);
   }

   return buf;
 }

 //-------------------------------------------------------------------------
 // BacktraceCurrent functions.
 //-------------------------------------------------------------------------
 BacktraceCurrent::BacktraceCurrent(BacktraceImpl* impl) : Backtrace(impl) {
   map_info_ = backtrace_create_map_info_list(-1);

   backtrace_.pid = getpid();
 }

 BacktraceCurrent::~BacktraceCurrent() {
 }

 bool BacktraceCurrent::ReadWord(uintptr_t ptr, uint32_t* out_value) {
   if (!VerifyReadWordArgs(ptr, out_value)) {
     return false;
   }

   const backtrace_map_info_t* map_info = FindMapInfo(ptr);
   if (map_info && map_info->is_readable) {
     *out_value = *reinterpret_cast<uint32_t*>(ptr);
     return true;
   } else {
     ALOGW("BacktraceCurrent::readWord: pointer %p not in a readbale map", reinterpret_cast<void*>(ptr));
     *out_value = static_cast<uint32_t>(-1);
     return false;
   }
 }

 //-------------------------------------------------------------------------
 // BacktracePtrace functions.
 //-------------------------------------------------------------------------
 BacktracePtrace::BacktracePtrace(BacktraceImpl* impl, pid_t pid, pid_t tid)
     : Backtrace(impl) {
   map_info_ = backtrace_create_map_info_list(tid);

   backtrace_.pid = pid;
   backtrace_.tid = tid;
 }

 BacktracePtrace::~BacktracePtrace() {
 }

 bool BacktracePtrace::ReadWord(uintptr_t ptr, uint32_t* out_value) {
   if (!VerifyReadWordArgs(ptr, out_value)) {
     return false;
   }

 #if defined(__APPLE__)
   ALOGW("BacktracePtrace::readWord: MacOS does not support reading from another pid.\n");
   return false;
 #else
   // ptrace() returns -1 and sets errno when the operation fails.
   // To disambiguate -1 from a valid result, we clear errno beforehand.
   errno = 0;
   *out_value = ptrace(PTRACE_PEEKTEXT, Tid(), reinterpret_cast<void*>(ptr), NULL);
   if (*out_value == static_cast<uint32_t>(-1) && errno) {
     ALOGW("BacktracePtrace::readWord: invalid pointer 0x%08x reading from tid %d, "
           "ptrace() errno=%d", ptr, Tid(), errno);
     return false;
   }
   return true;
 #endif
 }

 Backtrace* Backtrace::Create(pid_t pid, pid_t tid) {
   if (pid < 0 || pid == getpid()) {
     if (tid < 0 || tid == gettid()) {
       return CreateCurrentObj();
     } else {
       return CreateThreadObj(tid);
     }
   } else if (tid < 0) {
     return CreatePtraceObj(pid, pid);
   } else {
     return CreatePtraceObj(pid, tid);
   }
 }

 //-------------------------------------------------------------------------
 // Common interface functions.
 //-------------------------------------------------------------------------
 bool backtrace_create_context(
     backtrace_context_t* context, pid_t pid, pid_t tid, size_t num_ignore_frames) {
   Backtrace* backtrace = Backtrace::Create(pid, tid);
   if (!backtrace) {
     return false;
   }
   if (!backtrace->Unwind(num_ignore_frames)) {
     delete backtrace;
     return false;
   }

   context->data = backtrace;
   context->backtrace = backtrace->GetBacktrace();
   return true;
 }

 void backtrace_destroy_context(backtrace_context_t* context) {
   if (context->data) {
     Backtrace* backtrace = reinterpret_cast<Backtrace*>(context->data);
     delete backtrace;
     context->data = NULL;
   }
   context->backtrace = NULL;
 }

 const backtrace_t* backtrace_get_data(backtrace_context_t* context) {
   if (context && context->data) {
     Backtrace* backtrace = reinterpret_cast<Backtrace*>(context->data);
     return backtrace->GetBacktrace();
   }
   return NULL;
 }

 bool backtrace_read_word(const backtrace_context_t* context, uintptr_t ptr, uint32_t* value) {
   if (context->data) {
     Backtrace* backtrace = reinterpret_cast<Backtrace*>(context->data);
     return backtrace->ReadWord(ptr, value);
   }
   return true;
 }

 const char* backtrace_get_map_name(const backtrace_context_t* context, uintptr_t pc, uintptr_t* map_start) {
   if (context->data) {
     Backtrace* backtrace = reinterpret_cast<Backtrace*>(context->data);
     return backtrace->GetMapName(pc, map_start);
   }
   return NULL;
 }

 char* backtrace_get_func_name(const backtrace_context_t* context, uintptr_t pc, uintptr_t* func_offset) {
   if (context->data) {
     Backtrace* backtrace = reinterpret_cast<Backtrace*>(context->data);
     std::string func_name = backtrace->GetFunctionName(pc, func_offset);
     if (!func_name.empty()) {
       return strdup(func_name.c_str());
     }
   }
   return NULL;
 }

 void backtrace_format_frame_data(
     const backtrace_context_t* context, size_t frame_num, char* buf,
     size_t buf_size) {
   if (buf_size == 0 || buf == NULL) {
     ALOGW("backtrace_format_frame_data: bad call buf %p buf_size %zu\n",
           buf, buf_size);
     return;
   }
   if (context->data) {
     Backtrace* backtrace = reinterpret_cast<Backtrace*>(context->data);
     std::string line = backtrace->FormatFrameData(frame_num);
     if (line.size() > buf_size) {
       memcpy(buf, line.c_str(), buf_size-1);
       buf[buf_size] = '\0';
     } else {
       memcpy(buf, line.c_str(), line.size()+1);
     }
   }
 }
	/*
	* Copyright (C) 2013 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include <errno.h>
	#include <stdlib.h>
	#include <string.h>
	#include <sys/ptrace.h>
	#include <sys/types.h>
	#include <unistd.h>

	#define __STDC_FORMAT_MACROS
	#include <inttypes.h>

	#include <string>

	#include <backtrace/Backtrace.h>
	#include <cutils/log.h>

	#include "Backtrace.h"
	#include "thread_utils.h"

	//-------------------------------------------------------------------------
	// BacktraceImpl functions.
	//-------------------------------------------------------------------------
	backtrace_t* BacktraceImpl::GetBacktraceData() {
	return &backtrace_obj_->backtrace_;
	}

	//-------------------------------------------------------------------------
	// Backtrace functions.
	//-------------------------------------------------------------------------
	Backtrace::Backtrace(BacktraceImpl* impl) : impl_(impl), map_info_(NULL) {
	impl_->SetParent(this);
	backtrace_.num_frames = 0;
	backtrace_.pid = -1;
	backtrace_.tid = -1;
	}

	Backtrace::~Backtrace() {
	for (size_t i = 0; i < NumFrames(); i++) {
	if (backtrace_.frames[i].func_name) {
	free(backtrace_.frames[i].func_name);
	backtrace_.frames[i].func_name = NULL;
	}
	}

	if (map_info_) {
	backtrace_destroy_map_info_list(map_info_);
	map_info_ = NULL;
	}

	if (impl_) {
	delete impl_;
	impl_ = NULL;
	}
	}

	bool Backtrace::Unwind(size_t num_ignore_frames) {
	return impl_->Unwind(num_ignore_frames);
	}

	__BEGIN_DECLS
	extern char* __cxa_demangle (const char* mangled, char* buf, size_t* len,
	int* status);
	__END_DECLS

	std::string Backtrace::GetFunctionName(uintptr_t pc, uintptr_t* offset) {
	std::string func_name = impl_->GetFunctionNameRaw(pc, offset);
	if (!func_name.empty()) {
	#if defined(__APPLE__)
	// Mac OS' __cxa_demangle demangles "f" as "float"; last tested on 10.7.
	if (symbol_name[0] != '_') {
	return func_name;
	}
	#endif
	char* name = __cxa_demangle(func_name.c_str(), 0, 0, 0);
	if (name) {
	func_name = name;
	free(name);
	}
	}
	return func_name;
	}

	bool Backtrace::VerifyReadWordArgs(uintptr_t ptr, uint32_t* out_value) {
	if (ptr & 3) {
	ALOGW("Backtrace::verifyReadWordArgs: invalid pointer %p", (void*)ptr);
	*out_value = (uint32_t)-1;
	return false;
	}
	return true;
	}

	const char* Backtrace::GetMapName(uintptr_t pc, uintptr_t* map_start) {
	const backtrace_map_info_t* map_info = FindMapInfo(pc);
	if (map_info) {
	if (map_start) {
	*map_start = map_info->start;
	}
	return map_info->name;
	}
	return NULL;
	}

	const backtrace_map_info_t* Backtrace::FindMapInfo(uintptr_t ptr) {
	return backtrace_find_map_info(map_info_, ptr);
	}

	std::string Backtrace::FormatFrameData(size_t frame_num) {
	backtrace_frame_data_t* frame = &backtrace_.frames[frame_num];
	const char* map_name;
	if (frame->map_name) {
	map_name = frame->map_name;
	} else {
	map_name = "<unknown>";
	}
	uintptr_t relative_pc;
	if (frame->map_offset) {
	relative_pc = frame->map_offset;
	} else {
	relative_pc = frame->pc;
	}

	char buf[512];
	if (frame->func_name && frame->func_offset) {
	snprintf(buf, sizeof(buf), "#%02zu pc %0*" PRIxPTR " %s (%s+%" PRIuPTR ")",
	frame_num, (int)sizeof(uintptr_t)*2, relative_pc, map_name,
	frame->func_name, frame->func_offset);
	} else if (frame->func_name) {
	snprintf(buf, sizeof(buf), "#%02zu pc %0*" PRIxPTR " %s (%s)", frame_num,
	(int)sizeof(uintptr_t)*2, relative_pc, map_name, frame->func_name);
	} else {
	snprintf(buf, sizeof(buf), "#%02zu pc %0*" PRIxPTR " %s", frame_num,
	(int)sizeof(uintptr_t)*2, relative_pc, map_name);
	}

	return buf;
	}

	//-------------------------------------------------------------------------
	// BacktraceCurrent functions.
	//-------------------------------------------------------------------------
	BacktraceCurrent::BacktraceCurrent(BacktraceImpl* impl) : Backtrace(impl) {
	map_info_ = backtrace_create_map_info_list(-1);

	backtrace_.pid = getpid();
	}

	BacktraceCurrent::~BacktraceCurrent() {
	}

	bool BacktraceCurrent::ReadWord(uintptr_t ptr, uint32_t* out_value) {
	if (!VerifyReadWordArgs(ptr, out_value)) {
	return false;
	}

	const backtrace_map_info_t* map_info = FindMapInfo(ptr);
	if (map_info && map_info->is_readable) {
	out_value = reinterpret_cast<uint32_t*>(ptr);
	return true;
	} else {
	ALOGW("BacktraceCurrent::readWord: pointer %p not in a readbale map", reinterpret_cast<void*>(ptr));
	*out_value = static_cast<uint32_t>(-1);
	return false;
	}
	}

	//-------------------------------------------------------------------------
	// BacktracePtrace functions.
	//-------------------------------------------------------------------------
	BacktracePtrace::BacktracePtrace(BacktraceImpl* impl, pid_t pid, pid_t tid)
	: Backtrace(impl) {
	map_info_ = backtrace_create_map_info_list(tid);

	backtrace_.pid = pid;
	backtrace_.tid = tid;
	}

	BacktracePtrace::~BacktracePtrace() {
	}

	bool BacktracePtrace::ReadWord(uintptr_t ptr, uint32_t* out_value) {
	if (!VerifyReadWordArgs(ptr, out_value)) {
	return false;
	}

	#if defined(__APPLE__)
	ALOGW("BacktracePtrace::readWord: MacOS does not support reading from another pid.\n");
	return false;
	#else
	// ptrace() returns -1 and sets errno when the operation fails.
	// To disambiguate -1 from a valid result, we clear errno beforehand.
	errno = 0;
	out_value = ptrace(PTRACE_PEEKTEXT, Tid(), reinterpret_cast<void>(ptr), NULL);
	if (*out_value == static_cast<uint32_t>(-1) && errno) {
	ALOGW("BacktracePtrace::readWord: invalid pointer 0x%08x reading from tid %d, "
	"ptrace() errno=%d", ptr, Tid(), errno);
	return false;
	}
	return true;
	#endif
	}

	Backtrace* Backtrace::Create(pid_t pid, pid_t tid) {
	if (pid < 0 \|\| pid == getpid()) {
	if (tid < 0 \|\| tid == gettid()) {
	return CreateCurrentObj();
	} else {
	return CreateThreadObj(tid);
	}
	} else if (tid < 0) {
	return CreatePtraceObj(pid, pid);
	} else {
	return CreatePtraceObj(pid, tid);
	}
	}

	//-------------------------------------------------------------------------
	// Common interface functions.
	//-------------------------------------------------------------------------
	bool backtrace_create_context(
	backtrace_context_t* context, pid_t pid, pid_t tid, size_t num_ignore_frames) {
	Backtrace* backtrace = Backtrace::Create(pid, tid);
	if (!backtrace) {
	return false;
	}
	if (!backtrace->Unwind(num_ignore_frames)) {
	delete backtrace;
	return false;
	}

	context->data = backtrace;
	context->backtrace = backtrace->GetBacktrace();
	return true;
	}

	void backtrace_destroy_context(backtrace_context_t* context) {
	if (context->data) {
	Backtrace* backtrace = reinterpret_cast<Backtrace*>(context->data);
	delete backtrace;
	context->data = NULL;
	}
	context->backtrace = NULL;
	}

	const backtrace_t* backtrace_get_data(backtrace_context_t* context) {
	if (context && context->data) {
	Backtrace* backtrace = reinterpret_cast<Backtrace*>(context->data);
	return backtrace->GetBacktrace();
	}
	return NULL;
	}

	bool backtrace_read_word(const backtrace_context_t* context, uintptr_t ptr, uint32_t* value) {
	if (context->data) {
	Backtrace* backtrace = reinterpret_cast<Backtrace*>(context->data);
	return backtrace->ReadWord(ptr, value);
	}
	return true;
	}

	const char* backtrace_get_map_name(const backtrace_context_t* context, uintptr_t pc, uintptr_t* map_start) {
	if (context->data) {
	Backtrace* backtrace = reinterpret_cast<Backtrace*>(context->data);
	return backtrace->GetMapName(pc, map_start);
	}
	return NULL;
	}

	char* backtrace_get_func_name(const backtrace_context_t* context, uintptr_t pc, uintptr_t* func_offset) {
	if (context->data) {
	Backtrace* backtrace = reinterpret_cast<Backtrace*>(context->data);
	std::string func_name = backtrace->GetFunctionName(pc, func_offset);
	if (!func_name.empty()) {
	return strdup(func_name.c_str());
	}
	}
	return NULL;
	}

	void backtrace_format_frame_data(
	const backtrace_context_t* context, size_t frame_num, char* buf,
	size_t buf_size) {
	if (buf_size == 0 \|\| buf == NULL) {
	ALOGW("backtrace_format_frame_data: bad call buf %p buf_size %zu\n",
	buf, buf_size);
	return;
	}
	if (context->data) {
	Backtrace* backtrace = reinterpret_cast<Backtrace*>(context->data);
	std::string line = backtrace->FormatFrameData(frame_num);
	if (line.size() > buf_size) {
	memcpy(buf, line.c_str(), buf_size-1);
	buf[buf_size] = '\0';
	} else {
	memcpy(buf, line.c_str(), line.size()+1);
	}
	}
	}