Rewrite libbacktrace using C++.
The old code was essentially trying to be C++ in C and was awkward. This
change makes it all objects with a thin layer that C code can use.
There is a C++ backtrace object that is not very useful, this code will
replace it.
This change also includes moving the backtrace test to a gtest, and adding
coverage of all major functionality.
Bug: 8410085
Change-Id: Iae0f1b09b3dd60395f71ed66010c1ea5cdd37841
diff --git a/include/backtrace/Backtrace.h b/include/backtrace/Backtrace.h
new file mode 100644
index 0000000..0b75e83
--- /dev/null
+++ b/include/backtrace/Backtrace.h
@@ -0,0 +1,85 @@
+/*
+ * 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.
+ */
+
+#ifndef _BACKTRACE_BACKTRACE_H
+#define _BACKTRACE_BACKTRACE_H
+
+#include <backtrace/backtrace.h>
+
+#include <string>
+
+class BacktraceImpl;
+
+class Backtrace {
+public:
+ Backtrace(BacktraceImpl* impl);
+ virtual ~Backtrace();
+
+ // Get the current stack trace and store in the backtrace_ structure.
+ virtual bool Unwind(size_t num_ignore_frames);
+
+ // Get the function name and offset into the function given the pc.
+ // If the string is empty, then no valid function name was found.
+ virtual std::string GetFunctionName(uintptr_t pc, uintptr_t* offset);
+
+ // Get the name of the map associated with the given pc. If NULL is returned,
+ // then map_start is not set. Otherwise, map_start is the beginning of this
+ // map.
+ virtual const char* GetMapName(uintptr_t pc, uintptr_t* map_start);
+
+ // Finds the memory map associated with the given ptr.
+ virtual const backtrace_map_info_t* FindMapInfo(uintptr_t ptr);
+
+ // Read the data at a specific address.
+ virtual bool ReadWord(uintptr_t ptr, uint32_t* out_value) = 0;
+
+ // Create a string representing the formatted line of backtrace information
+ // for a single frame.
+ virtual std::string FormatFrameData(size_t frame_num);
+
+ pid_t Pid() { return backtrace_.pid; }
+ pid_t Tid() { return backtrace_.tid; }
+ size_t NumFrames() { return backtrace_.num_frames; }
+
+ const backtrace_t* GetBacktrace() { return &backtrace_; }
+
+ const backtrace_frame_data_t* GetFrame(size_t frame_num) {
+ return &backtrace_.frames[frame_num];
+ }
+
+ // Create the correct Backtrace object based on what is to be unwound.
+ // If pid < 0 or equals the current pid, then the Backtrace object
+ // corresponds to the current process.
+ // If pid < 0 or equals the current pid and tid >= 0, then the Backtrace
+ // object corresponds to a thread in the current process.
+ // If pid >= 0 and tid < 0, then the Backtrace object corresponds to a
+ // different process.
+ // Tracing a thread in a different process is not supported.
+ static Backtrace* Create(pid_t pid, pid_t tid);
+
+protected:
+ virtual bool VerifyReadWordArgs(uintptr_t ptr, uint32_t* out_value);
+
+ BacktraceImpl* impl_;
+
+ backtrace_map_info_t* map_info_;
+
+ backtrace_t backtrace_;
+
+ friend class BacktraceImpl;
+};
+
+#endif // _BACKTRACE_BACKTRACE_H
diff --git a/include/backtrace/backtrace.h b/include/backtrace/backtrace.h
index b6bff38..b35a6d5 100644
--- a/include/backtrace/backtrace.h
+++ b/include/backtrace/backtrace.h
@@ -21,9 +21,7 @@
#include <stdbool.h>
#include <inttypes.h>
-#ifdef __cplusplus
-extern "C" {
-#endif
+__BEGIN_DECLS
#define MAX_BACKTRACE_FRAMES 64
@@ -43,48 +41,58 @@
size_t stack_size; /* The size of the stack, zero indicate an unknown stack size. */
const char* map_name; /* The name of the map to which this pc belongs, NULL indicates the pc doesn't belong to a known map. */
uintptr_t map_offset; /* pc relative to the start of the map, only valid if map_name is not NULL. */
- char* proc_name; /* The function name associated with this pc, NULL if not found. */
- uintptr_t proc_offset; /* pc relative to the start of the procedure, only valid if proc_name is not NULL. */
+ char* func_name; /* The function name associated with this pc, NULL if not found. */
+ uintptr_t func_offset; /* pc relative to the start of the function, only valid if func_name is not NULL. */
} backtrace_frame_data_t;
typedef struct {
backtrace_frame_data_t frames[MAX_BACKTRACE_FRAMES];
size_t num_frames;
+ pid_t pid;
pid_t tid;
backtrace_map_info_t* map_info_list;
- void* private_data;
} backtrace_t;
-/* Gather the backtrace data for tid and fill in the backtrace structure.
- * If tid < 0, then gather the backtrace for the current thread.
- */
-bool backtrace_get_data(backtrace_t* backtrace, pid_t tid);
+typedef struct {
+ void* data;
+ const backtrace_t* backtrace;
+} backtrace_context_t;
-/* Free any memory associated with the backtrace structure. */
-void backtrace_free_data(backtrace_t* backtrace);
+/* Create a context for the backtrace data and gather the backtrace.
+ * If pid < 0, then gather the backtrace for the current process.
+ */
+bool backtrace_create_context(
+ backtrace_context_t* context, pid_t pid, pid_t tid, size_t num_ignore_frames);
+
+/* Gather the backtrace data for a pthread instead of a process. */
+bool backtrace_create_thread_context(
+ backtrace_context_t* context, pid_t tid, size_t num_ignore_frames);
+
+/* Free any memory allocated during the context create. */
+void backtrace_destroy_context(backtrace_context_t* context);
/* Read data at a specific address for a process. */
bool backtrace_read_word(
- const backtrace_t* backtrace, uintptr_t ptr, uint32_t* value);
+ const backtrace_context_t* context, uintptr_t ptr, uint32_t* value);
-/* Get information about the map associated with a pc. If NULL is
+/* Get information about the map name associated with a pc. If NULL is
* returned, then map_start is not set.
*/
-const char* backtrace_get_map_info(
- const backtrace_t* backtrace, uintptr_t pc, uintptr_t* map_start);
+const char* backtrace_get_map_name(
+ const backtrace_context_t* context, uintptr_t pc, uintptr_t* map_start);
-/* Get the procedure name and offest given the pc. If NULL is returned,
- * then proc_offset is not set. The returned string is allocated using
+/* Get the function name and offset given the pc. If NULL is returned,
+ * then func_offset is not set. The returned string is allocated using
* malloc and must be freed by the caller.
*/
-char* backtrace_get_proc_name(
- const backtrace_t* backtrace, uintptr_t pc, uintptr_t* proc_offset);
+char* backtrace_get_func_name(
+ const backtrace_context_t* context, uintptr_t pc, uintptr_t* func_offset);
-/* Loads memory map from /proc/<tid>/maps. If tid < 0, then load the memory
+/* Loads memory map from /proc/<pid>/maps. If pid < 0, then load the memory
* map for the current process.
*/
-backtrace_map_info_t* backtrace_create_map_info_list(pid_t tid);
+backtrace_map_info_t* backtrace_create_map_info_list(pid_t pid);
/* Frees memory associated with the map list. */
void backtrace_destroy_map_info_list(backtrace_map_info_t* map_info_list);
@@ -95,10 +103,12 @@
/* Create a formatted line of backtrace information for a single frame. */
void backtrace_format_frame_data(
- const backtrace_frame_data_t* frame, size_t frame_num, char *buf, size_t buf_size);
+ const backtrace_context_t* context, size_t frame_num, char* buf,
+ size_t buf_size);
-#ifdef __cplusplus
-}
-#endif
+/* Get the backtrace data structure associated with the context. */
+const backtrace_t* backtrace_get_data(backtrace_context_t* context);
+
+__END_DECLS
#endif /* _BACKTRACE_H */