示例#1
0
文件: asm.go 项目: tidatida/go
func elfsetupplt() {
	plt := ld.Linklookup(ld.Ctxt, ".plt", 0)
	got := ld.Linklookup(ld.Ctxt, ".got.plt", 0)
	if plt.Size == 0 {
		// pushq got+8(IP)
		ld.Adduint8(ld.Ctxt, plt, 0xff)

		ld.Adduint8(ld.Ctxt, plt, 0x35)
		ld.Addpcrelplus(ld.Ctxt, plt, got, 8)

		// jmpq got+16(IP)
		ld.Adduint8(ld.Ctxt, plt, 0xff)

		ld.Adduint8(ld.Ctxt, plt, 0x25)
		ld.Addpcrelplus(ld.Ctxt, plt, got, 16)

		// nopl 0(AX)
		ld.Adduint32(ld.Ctxt, plt, 0x00401f0f)

		// assume got->size == 0 too
		ld.Addaddrplus(ld.Ctxt, got, ld.Linklookup(ld.Ctxt, ".dynamic", 0), 0)

		ld.Adduint64(ld.Ctxt, got, 0)
		ld.Adduint64(ld.Ctxt, got, 0)
	}
}
示例#2
0
文件: asm.go 项目: xslonepiece/goios
func elfsetupplt() {
	plt := ld.Linklookup(ld.Ctxt, ".plt", 0)
	got := ld.Linklookup(ld.Ctxt, ".got.plt", 0)
	if plt.Size == 0 {
		// str lr, [sp, #-4]!
		ld.Adduint32(ld.Ctxt, plt, 0xe52de004)

		// ldr lr, [pc, #4]
		ld.Adduint32(ld.Ctxt, plt, 0xe59fe004)

		// add lr, pc, lr
		ld.Adduint32(ld.Ctxt, plt, 0xe08fe00e)

		// ldr pc, [lr, #8]!
		ld.Adduint32(ld.Ctxt, plt, 0xe5bef008)

		// .word &GLOBAL_OFFSET_TABLE[0] - .
		ld.Addpcrelplus(ld.Ctxt, plt, got, 4)

		// the first .plt entry requires 3 .plt.got entries
		ld.Adduint32(ld.Ctxt, got, 0)

		ld.Adduint32(ld.Ctxt, got, 0)
		ld.Adduint32(ld.Ctxt, got, 0)
	}
}
示例#3
0
文件: asm.go 项目: xslonepiece/goios
func gentext() {
	if !ld.DynlinkingGo() {
		return
	}
	addmoduledata := ld.Linklookup(ld.Ctxt, "runtime.addmoduledata", 0)
	if addmoduledata.Type == ld.STEXT {
		// we're linking a module containing the runtime -> no need for
		// an init function
		return
	}
	addmoduledata.Reachable = true
	initfunc := ld.Linklookup(ld.Ctxt, "go.link.addmoduledata", 0)
	initfunc.Type = ld.STEXT
	initfunc.Local = true
	initfunc.Reachable = true
	o := func(op ...uint8) {
		for _, op1 := range op {
			ld.Adduint8(ld.Ctxt, initfunc, op1)
		}
	}
	// 0000000000000000 <local.dso_init>:
	//    0:	48 8d 3d 00 00 00 00 	lea    0x0(%rip),%rdi        # 7 <local.dso_init+0x7>
	// 			3: R_X86_64_PC32	runtime.firstmoduledata-0x4
	o(0x48, 0x8d, 0x3d)
	ld.Addpcrelplus(ld.Ctxt, initfunc, ld.Linklookup(ld.Ctxt, "runtime.firstmoduledata", 0), 0)
	//    7:	e8 00 00 00 00       	callq  c <local.dso_init+0xc>
	// 			8: R_X86_64_PLT32	runtime.addmoduledata-0x4
	o(0xe8)
	Addcall(ld.Ctxt, initfunc, addmoduledata)
	//    c:	c3                   	retq
	o(0xc3)
	if ld.Ctxt.Etextp != nil {
		ld.Ctxt.Etextp.Next = initfunc
	} else {
		ld.Ctxt.Textp = initfunc
	}
	ld.Ctxt.Etextp = initfunc
	initarray_entry := ld.Linklookup(ld.Ctxt, "go.link.addmoduledatainit", 0)
	initarray_entry.Reachable = true
	initarray_entry.Local = true
	initarray_entry.Type = ld.SINITARR
	ld.Addaddr(ld.Ctxt, initarray_entry, initfunc)
}
示例#4
0
文件: asm.go 项目: tidatida/go
func addpltsym(s *ld.LSym) {
	if s.Plt >= 0 {
		return
	}

	adddynsym(ld.Ctxt, s)

	if ld.Iself {
		plt := ld.Linklookup(ld.Ctxt, ".plt", 0)
		got := ld.Linklookup(ld.Ctxt, ".got.plt", 0)
		rela := ld.Linklookup(ld.Ctxt, ".rela.plt", 0)
		if plt.Size == 0 {
			elfsetupplt()
		}

		// jmpq *got+size(IP)
		ld.Adduint8(ld.Ctxt, plt, 0xff)

		ld.Adduint8(ld.Ctxt, plt, 0x25)
		ld.Addpcrelplus(ld.Ctxt, plt, got, got.Size)

		// add to got: pointer to current pos in plt
		ld.Addaddrplus(ld.Ctxt, got, plt, plt.Size)

		// pushq $x
		ld.Adduint8(ld.Ctxt, plt, 0x68)

		ld.Adduint32(ld.Ctxt, plt, uint32((got.Size-24-8)/8))

		// jmpq .plt
		ld.Adduint8(ld.Ctxt, plt, 0xe9)

		ld.Adduint32(ld.Ctxt, plt, uint32(-(plt.Size + 4)))

		// rela
		ld.Addaddrplus(ld.Ctxt, rela, got, got.Size-8)

		ld.Adduint64(ld.Ctxt, rela, ld.ELF64_R_INFO(uint32(s.Dynid), ld.R_X86_64_JMP_SLOT))
		ld.Adduint64(ld.Ctxt, rela, 0)

		s.Plt = int32(plt.Size - 16)
	} else if ld.HEADTYPE == ld.Hdarwin {
		// To do lazy symbol lookup right, we're supposed
		// to tell the dynamic loader which library each
		// symbol comes from and format the link info
		// section just so.  I'm too lazy (ha!) to do that
		// so for now we'll just use non-lazy pointers,
		// which don't need to be told which library to use.
		//
		// http://networkpx.blogspot.com/2009/09/about-lcdyldinfoonly-command.html
		// has details about what we're avoiding.

		addgotsym(s)
		plt := ld.Linklookup(ld.Ctxt, ".plt", 0)

		ld.Adduint32(ld.Ctxt, ld.Linklookup(ld.Ctxt, ".linkedit.plt", 0), uint32(s.Dynid))

		// jmpq *got+size(IP)
		s.Plt = int32(plt.Size)

		ld.Adduint8(ld.Ctxt, plt, 0xff)
		ld.Adduint8(ld.Ctxt, plt, 0x25)
		ld.Addpcrelplus(ld.Ctxt, plt, ld.Linklookup(ld.Ctxt, ".got", 0), int64(s.Got))
	} else {
		ld.Diag("addpltsym: unsupported binary format")
	}
}