github.com/bytedance/mockey@v1.2.10/internal/monkey/inst/disasm_amd64.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 inst
    18  
    19  import (
    20  	"reflect"
    21  	"unsafe"
    22  
    23  	"github.com/bytedance/mockey/internal/monkey/common"
    24  	"github.com/bytedance/mockey/internal/tool"
    25  	"golang.org/x/arch/x86/x86asm"
    26  )
    27  
    28  func calcFnAddrRange(name string, fn func()) (uintptr, uintptr) {
    29  	v := reflect.ValueOf(fn)
    30  	var start, end uintptr
    31  	start = v.Pointer()
    32  	maxScan := 2000
    33  	code := common.BytesOf(v.Pointer(), 2000)
    34  	pos := 0
    35  
    36  	for pos < maxScan {
    37  		inst, err := x86asm.Decode(code[pos:], 64)
    38  		tool.Assert(err == nil, err)
    39  
    40  		args := []interface{}{name, inst.Op}
    41  		for i := range inst.Args {
    42  			args = append(args, inst.Args[i])
    43  		}
    44  		tool.DebugPrintf("init: <%v>\t%v\t%v\t%v\t%v\t%v\t%v\n", args...)
    45  
    46  		if inst.Op == x86asm.RET {
    47  			end = start + uintptr(pos)
    48  			tool.DebugPrintf("init: %v(%v,%v)\n", name, start, end)
    49  			return start, end
    50  		}
    51  
    52  		pos += int(inst.Len)
    53  	}
    54  	tool.Assert(false, "%v ret not found", name)
    55  	return 0, 0
    56  }
    57  
    58  func Disassemble(code []byte, required int, checkLen bool) int {
    59  	var pos int
    60  	var err error
    61  	var inst x86asm.Inst
    62  
    63  	for pos < required {
    64  		inst, err = x86asm.Decode(code[pos:], 64)
    65  		tool.Assert(err == nil, err)
    66  		tool.DebugPrintf("Disassemble: inst: %v\n", inst)
    67  		tool.Assert(inst.Op != x86asm.RET || !checkLen, "function is too short to patch")
    68  		pos += inst.Len
    69  	}
    70  	return pos
    71  }
    72  
    73  func GetGenericJumpAddr(addr uintptr, maxScan uint64) uintptr {
    74  	code := common.BytesOf(addr, int(maxScan))
    75  	var pos uint64
    76  	var err error
    77  	var inst x86asm.Inst
    78  
    79  	allAddrs := []uintptr{}
    80  	for pos < maxScan {
    81  		inst, err = x86asm.Decode(code[pos:], 64)
    82  		tool.Assert(err == nil, err)
    83  
    84  		args := []interface{}{inst.Op}
    85  		for i := range inst.Args {
    86  			args = append(args, inst.Args[i])
    87  		}
    88  		tool.DebugPrintf("%v\t%v\t%v\t%v\t%v\t%v\n", args...)
    89  
    90  		if inst.Op == x86asm.RET {
    91  			break
    92  		}
    93  
    94  		if inst.Op == x86asm.CALL {
    95  			rel := int32(inst.Args[0].(x86asm.Rel))
    96  			fnAddr := calcAddr(uintptr(unsafe.Pointer(&code[0]))+uintptr(pos+uint64(inst.Len)), rel)
    97  			isExtraCall, extraName := isGenericProxyCallExtra(fnAddr)
    98  			tool.DebugPrintf("found CALL, raw is: %x, rel: %v,  raw is: %x,  fnAddr: %v, isExtraCall: %v, extraName: %v\n", inst.String(), rel, fnAddr, isExtraCall, extraName)
    99  			if !isExtraCall {
   100  				allAddrs = append(allAddrs, fnAddr)
   101  			}
   102  		}
   103  		pos += uint64(inst.Len)
   104  	}
   105  	tool.Assert(len(allAddrs) == 1, "invalid callAddr: %v", allAddrs)
   106  	return allAddrs[0]
   107  }
   108  
   109  func calcAddr(from uintptr, rel int32) uintptr {
   110  	tool.DebugPrintf("calc CALL addr, from: %x(%v) CALL: %x\n", from, from, rel)
   111  
   112  	var dest uintptr
   113  	if rel < 0 {
   114  		dest = from - uintptr(uint32(-rel))
   115  	} else {
   116  		dest = from + uintptr(rel)
   117  	}
   118  
   119  	tool.DebugPrintf("L->H:%v rel: %v from: %x(%v) dest: %x(%v), distance: %v\n", rel > 0, rel, from, from, dest, dest, from-dest)
   120  	return dest
   121  }