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/*
* Copyright (C) 2012 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "debug_stacktrace.h"
#include <dlfcn.h>
#include <inttypes.h>
#include <malloc.h>
#include <unistd.h>
#include <unwind.h>
#include <sys/types.h>
#include "debug_mapinfo.h"
#include "malloc_debug_disable.h"
#include "private/libc_logging.h"
#if defined(__LP64__)
#define PAD_PTR "016" PRIxPTR
#else
#define PAD_PTR "08" PRIxPTR
#endif
typedef struct _Unwind_Context __unwind_context;
extern "C" char* __cxa_demangle(const char*, char*, size_t*, int*);
static mapinfo_t* g_map_info = NULL;
__LIBC_HIDDEN__ void backtrace_startup() {
ScopedDisableDebugCalls disable;
g_map_info = mapinfo_create(getpid());
}
__LIBC_HIDDEN__ void backtrace_shutdown() {
ScopedDisableDebugCalls disable;
mapinfo_destroy(g_map_info);
}
struct stack_crawl_state_t {
uintptr_t* frames;
size_t frame_count;
size_t max_depth;
bool have_skipped_self;
stack_crawl_state_t(uintptr_t* frames, size_t max_depth)
: frames(frames), frame_count(0), max_depth(max_depth), have_skipped_self(false) {
}
};
static _Unwind_Reason_Code trace_function(__unwind_context* context, void* arg) {
stack_crawl_state_t* state = static_cast<stack_crawl_state_t*>(arg);
uintptr_t ip = _Unwind_GetIP(context);
// The first stack frame is get_backtrace itself. Skip it.
if (ip != 0 && !state->have_skipped_self) {
state->have_skipped_self = true;
return _URC_NO_REASON;
}
#if defined(__arm__)
/*
* The instruction pointer is pointing at the instruction after the bl(x), and
* the _Unwind_Backtrace routine already masks the Thumb mode indicator (LSB
* in PC). So we need to do a quick check here to find out if the previous
* instruction is a Thumb-mode BLX(2). If so subtract 2 otherwise 4 from PC.
*/
if (ip != 0) {
short* ptr = reinterpret_cast<short*>(ip);
// Thumb BLX(2)
if ((*(ptr-1) & 0xff80) == 0x4780) {
ip -= 2;
} else {
ip -= 4;
}
}
#endif
state->frames[state->frame_count++] = ip;
return (state->frame_count >= state->max_depth) ? _URC_END_OF_STACK : _URC_NO_REASON;
}
__LIBC_HIDDEN__ int get_backtrace(uintptr_t* frames, size_t max_depth) {
ScopedDisableDebugCalls disable;
stack_crawl_state_t state(frames, max_depth);
_Unwind_Backtrace(trace_function, &state);
return state.frame_count;
}
__LIBC_HIDDEN__ void log_backtrace(uintptr_t* frames, size_t frame_count) {
ScopedDisableDebugCalls disable;
uintptr_t self_bt[16];
if (frames == NULL) {
frame_count = get_backtrace(self_bt, 16);
frames = self_bt;
}
__libc_format_log(ANDROID_LOG_ERROR, "libc",
"*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***\n");
for (size_t i = 0 ; i < frame_count; ++i) {
uintptr_t offset = 0;
const char* symbol = NULL;
Dl_info info;
if (dladdr((void*) frames[i], &info) != 0) {
offset = reinterpret_cast<uintptr_t>(info.dli_saddr);
symbol = info.dli_sname;
}
uintptr_t rel_pc = offset;
const mapinfo_t* mi = (g_map_info != NULL) ? mapinfo_find(g_map_info, frames[i], &rel_pc) : NULL;
const char* soname = (mi != NULL) ? mi->name : info.dli_fname;
if (soname == NULL) {
soname = "<unknown>";
}
if (symbol != NULL) {
char* demangled_symbol = __cxa_demangle(symbol, NULL, NULL, NULL);
const char* best_name = (demangled_symbol != NULL) ? demangled_symbol : symbol;
__libc_format_log(ANDROID_LOG_ERROR, "libc",
" #%02zd pc %" PAD_PTR " %s (%s+%" PRIuPTR ")",
i, rel_pc, soname, best_name, frames[i] - offset);
free(demangled_symbol);
} else {
__libc_format_log(ANDROID_LOG_ERROR, "libc",
" #%02zd pc %" PAD_PTR " %s",
i, rel_pc, soname);
}
}
}
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