goloader

package module
v0.0.9 Latest Latest
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 Go to latest Published: Jul 13, 2020 License: Apache-2.0 Imports: 14 Imported by: 8

README

Goloader

Build Status

Goloader can load and run Golang code at runtime.

Forked from dearplain/goloader, Take over maintenance because the original author is not in maintenance

How does it work?

Goloader works like a linker: it relocates the address of symbols in an object file, generates runnable code, and then reuses the runtime function and the type pointer of the loader.

Goloader provides some information to the runtime and gc of Go, which allows it to work correctly with them.

Please note that Goloader is not a scripting engine. It reads the output of Go compiler and makes them runnable. All features of Go are supported, and run just as fast and lightweight as native Go code.

Comparison with plugin

Goloader reuses the Go runtime, which makes it much smaller. And code loaded by Goloader is unloadable.

Goloader is debuggable, and supports pprof tool(Yes, you can see code loaded by Goloader in pprof).

Build

Make sure you're using go >= 1.8.

First, execute the following command, then do build and test. This is because Goloader relies on the internal package, which is forbidden by the Go compiler.

cp -r $GOROOT/src/cmd/internal $GOROOT/src/cmd/objfile

Examples

go build github.com/pkujhd/goloader/examples/loader

go tool compile $GOPATH/src/github.com/pkujhd/goloader/examples/schedule/schedule.go
./loader -o schedule.o -run main.main -times 10

go tool compile $GOPATH/src/github.com/pkujhd/goloader/examples/base/base.go
./loader -o base.o -run main.main

go tool compile $GOPATH/src/github.com/pkujhd/goloader/examples/http/http.go
./loader -o http.o -run main.main

go install github.com/pkujhd/goloader/examples/basecontext
go tool compile -I $GOPATH/pkg/`go env GOOS`_`go env GOARCH`/ $GOPATH/src/github.com/pkujhd/goloader/examples/inter/inter.go
./loader -o $GOPATH/pkg/`go env GOOS`_`go env GOARCH`/github.com/pkujhd/goloader/examples/basecontext.a:github.com/pkujhd/goloader/examples/basecontext -o inter.o

#build multiple go files
go tool compile -I $GOPATH/pkg/`go env GOOS`_`go env GOARCH`/ -o test.o test1.go test2.go
./loader -o test.o -run main.main

Warning

This has currently only been tested and developed on:

Golang 1.8-1.14 (x64/x86, darwin, linux, windows)

Golang 1.10-1.14 (arm, linux)

Golang 1.8-1.14 (arm64(LE) linux)

Documentation

Index

Constants

View Source 
const (
	PtrSize    = 4 << (^uintptr(0) >> 63)
	Uint32Size = int(unsafe.Sizeof(uint32(0)))
	IntSize    = int(unsafe.Sizeof(int(0)))
	UInt64Size = int(unsafe.Sizeof(uint64(0)))

	ItabSize             = int(unsafe.Sizeof(itab{}))
	FindFuncBucketSize   = int(unsafe.Sizeof(findfuncbucket{}))
	InlinedCallSize      = int(unsafe.Sizeof(inlinedCall{}))
	INVALID_HANDLE_VALUE = ^uintptr(0)
	INVALID_OFFSET       = int(-1)
)

size

View Source 
const (
	TLSNAME        = "(TLS)"
	R_CALLIND_NAME = "R_CALLIND"
)
View Source 
const (
	ARCH_ARM32 = "arm"
	ARCH_ARM64 = "arm64"
	ARCH_386   = "386"
	ARCH_AMD64 = "amd64"
)

cpu arch

View Source 
const (
	EMPTY_STRING    = ""
	DEFAULT_PKGPATH = "main"
	ZERO_BYTE       = byte(0x00)
)
View Source 
const (
	RUNTIME_DEFERRETURN = "runtime.deferreturn"
	RUNTIME_INIT        = "runtime.init"
)

runtime symbol

View Source 
const (
	FILE_SYM_PREFIX        = "gofile.."
	TYPE_IMPORTPATH_PREFIX = "type..importpath."
	TYPE_DOUBLE_DOT_PREFIX = "type.."
	TYPE_PREFIX            = "type."
	ITAB_PREFIX            = "go.itab."
	RUNTIME_PREFIX         = "runtime."
	STKOBJ_SUFFIX          = ".stkobj"
	INLINETREE_SUFFIX      = ".inlinetree"
)

string match prefix/suffix

View Source 
const (
	R_ADDR = 1
	// R_ADDRARM64 relocates an adrp, add pair to compute the address of the
	// referenced symbol.
	R_ADDRARM64 = 3
	// R_ADDROFF resolves to a 32-bit offset from the beginning of the section
	// holding the data being relocated to the referenced symbol.
	R_ADDROFF = 5
	// R_WEAKADDROFF resolves just like R_ADDROFF but is a weak relocation.
	// A weak relocation does not make the symbol it refers to reachable,
	// and is only honored by the linker if the symbol is in some other way
	// reachable.
	R_WEAKADDROFF = 6
	R_CALL        = 8
	R_CALLARM     = 9
	R_CALLARM64   = 10
	R_CALLIND     = 11
)

copy from $GOROOT/src/cmd/internal/objabi/reloctype.go

Variables

This section is empty.

Functions

func Mmap 

func Mmap(size int) ([]byte, error)

func Munmap 

func Munmap(b []byte) (err error)

func RegSymbol 

func RegSymbol(symPtr map[string]uintptr) error

func RegTypes 

func RegTypes(symPtr map[string]uintptr, interfaces ...interface{})

Types

type CodeModule 

type CodeModule struct {
	Syms map[string]uintptr
	// contains filtered or unexported fields
}

func Load 

func Load(codereloc *CodeReloc, symPtr map[string]uintptr) (codeModule *CodeModule, err error)

func (*CodeModule) Unload 

func (cm *CodeModule) Unload()

type CodeReloc 

type CodeReloc struct {
	Arch string
	// contains filtered or unexported fields
}

func ReadObj 

func ReadObj(f *os.File) (*CodeReloc, error)

func ReadObjs 

func ReadObjs(files []string, pkgPath []string) (*CodeReloc, error)

type Func added in v0.0.7 

type Func struct {
	PCData   []uint32
	FuncData []uintptr
	Var      *[]goobj.Var
}

type Reloc 

type Reloc struct {
	Offset int
	Sym    *Sym
	Size   int
	Type   int
	Add    int
}

copy from $GOROOT/src/cmd/internal/goobj/read.go type Reloc struct

type Sym added in v0.0.5 

type Sym struct {
	Name   string
	Kind   int
	Offset int
	Func   *Func
	Reloc  []Reloc
}

copy from $GOROOT/src/cmd/internal/goobj/read.go type Sym struct

Source Files

View all Source files

Directories

Path Synopsis
examples
base command
basecontext
const command
http command
inline command
inter command
loader command
schedule command

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