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Backtrace in Android

#define MAX_DEPTH                       31#define MAX_BACKTRACE_LINE_LENGTH   800#define PATH "/system/lib/libcorkscrew.so"typedef ssize_t (*unwindFn)(backtrace_frame_t*, size_t, size_t);typedef void (*unwindSymbFn)(const backtrace_frame_t*, size_t, backtrace_symbol_t*);typedef void (*unwindSymbFreeFn)(backtrace_symbol_t*, size_t);static void *gHandle = NULL;static int getCallStack(void){    ssize_t i = 0;    ssize_t result = 0;    ssize_t count;    backtrace_frame_t mStack[MAX_DEPTH];    backtrace_symbol_t symbols[MAX_DEPTH];    unwindFn unwind_backtrace = NULL;    unwindSymbFn get_backtrace_symbols = NULL;    unwindSymbFreeFn free_backtrace_symbols = NULL;    // open the so.    if(gHandle == NULL) gHandle = dlopen(PATH, RTLD_NOW);    // get the interface for unwind and symbol analyse    if(gHandle != NULL) unwind_backtrace = (unwindFn)dlsym(gHandle, "unwind_backtrace");    if(gHandle != NULL) get_backtrace_symbols = (unwindSymbFn)dlsym(gHandle, "get_backtrace_symbols");    if(gHandle != NULL) free_backtrace_symbols = (unwindSymbFreeFn)dlsym(gHandle, "free_backtrace_symbols");    if(!gHandle ||!unwind_backtrace ||!get_backtrace_symbols || !free_backtrace_symbols  ){        ALOGE("Error! cannot get unwind info: handle:%p %p %p %p",            gHandle, unwind_backtrace, get_backtrace_symbols, free_backtrace_symbols );        return result;    }    count= unwind_backtrace(mStack, 1, MAX_DEPTH);    get_backtrace_symbols(mStack, count, symbols);    for (i = 0; i < count; i++) {        char line[MAX_BACKTRACE_LINE_LENGTH];        const char* mapName = symbols[i].map_name ? symbols[i].map_name : "
   
    ";        const char* symbolName =symbols[i].demangled_name ? symbols[i].demangled_name : symbols[i].symbol_name;        size_t fieldWidth = (MAX_BACKTRACE_LINE_LENGTH - 80) / 2;                if (symbolName) {            uint32_t pc_offset = symbols[i].relative_pc - symbols[i].relative_symbol_addr;            if (pc_offset) {                snprintf(line, MAX_BACKTRACE_LINE_LENGTH, "#%02d  pc %08x  %.*s (%.*s+%u)",                        i, symbols[i].relative_pc, fieldWidth, mapName,                        fieldWidth, symbolName, pc_offset);            } else {                snprintf(line, MAX_BACKTRACE_LINE_LENGTH, "#%02d  pc %08x  %.*s (%.*s)",                        i, symbols[i].relative_pc, fieldWidth, mapName,                        fieldWidth, symbolName);            }        } else {            snprintf(line, MAX_BACKTRACE_LINE_LENGTH, "#%02d  pc %08x  %.*s",                    i, symbols[i].relative_pc, fieldWidth, mapName);        }        ALOGD("%s", line);    }    free_backtrace_symbols(symbols, count);    return result;}
   

上面这个用法其实会缺几个头文件，到源码里抠出来，可能会有错误，修改下，经测试可以用。

在android5.0之后的做法

#incude "backtrace/Backtrace.h"int btdump(){    void * libbacktrace = dlopen("/system/lib/libbacktrace.so",RTLD_LOCAL);    if(!libbacktrace)    {        return -1;    }    Backtrace* (*create)(int,int,void*);    *(void**) &create = dlsym(libbacktrace,"_ZN9Backtrace6CreateEiiP12BacktraceMap");    if(!create)    {        return -1;    }    Backtrace* t = create(-1,-1,NULL);    if(!t)    {        return -1;    }    int ret = t->Unwind(0);    if(!ret)    {        return -1;    }    int count = t->NumFrames();    printf("Backtrace:\n")    for(i = 0; i < count; i++)    {        std::string line = t->FormatFrameData(i);        print("\t%s",line.c_str());    }    return 0;}

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