github.com/bytedance/mockey@v1.2.10/internal/monkey/fn/copy_darwin.go (about)

     1  /*
     2   * Copyright 2022 ByteDance Inc.
     3   *
     4   * Licensed under the Apache License, Version 2.0 (the "License");
     5   * you may not use this file except in compliance with the License.
     6   * You may obtain a copy of the License at
     7   *
     8   *     http://www.apache.org/licenses/LICENSE-2.0
     9   *
    10   * Unless required by applicable law or agreed to in writing, software
    11   * distributed under the License is distributed on an "AS IS" BASIS,
    12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13   * See the License for the specific language governing permissions and
    14   * limitations under the License.
    15   */
    16  
    17  package fn
    18  
    19  import (
    20  	"reflect"
    21  	"runtime"
    22  
    23  	"github.com/bytedance/mockey/internal/monkey/common"
    24  	"github.com/bytedance/mockey/internal/tool"
    25  )
    26  
    27  // Copy copies the original function code to a new page, injecting the code to the target function.
    28  func Copy(targetPtr, oriFn interface{}) {
    29  	targetVal := reflect.ValueOf(targetPtr)
    30  	tool.Assert(targetVal.Type().Kind() == reflect.Ptr, "'%v' is not a pointer", targetPtr)
    31  	targetType := targetVal.Type().Elem()
    32  	tool.Assert(targetType.Kind() == reflect.Func, "'%v' is not a function pointer", targetPtr)
    33  	oriVal := reflect.ValueOf(oriFn)
    34  	tool.Assert(tool.CheckFuncArgs(targetType, oriVal.Type(), 0, 0), "target and ori not match")
    35  
    36  	oriAddr := oriVal.Pointer()
    37  	tool.DebugPrintf("Copy: copy start for %v\n", runtime.FuncForPC(oriAddr).Name())
    38  	// allocate a new page to store copied fn
    39  	targetCode := common.AllocatePage()
    40  	oriCode := common.BytesOf(oriAddr, common.PageSize())
    41  	tool.DebugPrintf("Copy: target addr: 0x%x, ori addr: 0x%x\n", common.PtrOf(targetCode), oriAddr)
    42  	// copy ori fn code to target code
    43  	copyCode(targetCode, oriCode)
    44  	// inject target code into the target function
    45  	InjectInto(targetVal, targetCode)
    46  	tool.DebugPrintf("Copy: copy end for %v\n", runtime.FuncForPC(oriAddr).Name())
    47  }