Method GetStack

user/event/event_mmap2.go:187–241

(pid uint32, ubuf *UnwindBuf)

}

func (this *MapsHelper) GetStack(pid uint32, ubuf *UnwindBuf) (info string, err error) {
    // 当直接读取 maps 文件失败的时候 就采用这个方案获取堆栈
    maps_lock.Lock()
    defer maps_lock.Unlock()
    // 首先尝试获取 pid 对应的 maps 信息
    pid_maps, ok := this.pid_maps[pid]
    if !ok {
        return "", errors.New(fmt.Sprintf("[GetStack] get pid_maps failed by pid:%d", pid))
    }

    // perf_output_sample_ustack dump获取到的栈空间数据 起始地址就是 sp
    stack_buf := bytes.NewReader(ubuf.Data[:])
    fp := ubuf.Regs[common.REG_ARM64_X29]
    // lr := ubuf.Regs[common.REG_ARM64_LR]
    sp := ubuf.Regs[common.REG_ARM64_SP]
    pc := ubuf.Regs[common.REG_ARM64_PC]
    // 栈解析结果
    // var stack_arr []uint64
    var stack_infos []string
    // stack_arr = append(stack_arr, pc)
    stack_infos = append(stack_infos, this.GetRegionInfo(pid_maps, pc))
    // 奇怪 这里竟然没有 sp 所在的map信息
    // sp_region := this.GetRegion(pid_maps, sp)
    // this.logger.Printf("start:0x%x end:0x%x name:%s\n", sp_region.BaseAddr, sp_region.EndAddr, sp_region.LibName)
    // this.logger.Printf("pc:0x%x fp:0x%x sp:0x%x\n", pc, fp, sp)
    for i := 0; i < 20; i++ {
        // if fp < sp || fp < sp_region.BaseAddr || fp > sp_region.EndAddr {
        //     break
        // }
        if fp < sp {
            break
        }
        fp_offset := fp - sp
        stack_buf.Seek(int64(fp_offset), io.SeekStart)
        var next_fp uint64
        err = binary.Read(stack_buf, binary.LittleEndian, &next_fp)
        if err != nil {
            this.logger.Printf("read next_fp at offset:0x%x failed\n", fp_offset)
            break
        }
        var next_lr uint64
        err = binary.Read(stack_buf, binary.LittleEndian, &next_lr)
        if err != nil {
            this.logger.Printf("read next_lr at offset:0x%x failed\n", fp_offset+uint64(binary.Size(next_fp)))
            break
        }
        fp = next_fp
        if next_lr != 0 {
            stack_infos = append(stack_infos, this.GetRegionInfo(pid_maps, next_lr))
        }
    }
    backtrace := fmt.Sprintf("\t%s", strings.Join(stack_infos, "\n\t"))
    return backtrace, nil
    // return this.GetOffset(pid, addr), nil
}

func (this *MapsHelper) TryManualUpdateMaps(pid uint32, content []byte) error {
    maps_lock.Lock()