wasys: standalone/unsafe program runner

cmd/wasys/exec.go

@@ -0,0 +1,9 @@
+// Copyright (c) 2018 Timo Savola. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+func exec(textBase, stackLimit, memoryBase, memoryLimit, memoryGrowLimit, stackPtr uintptr)
+
+func callSys()

cmd/wasys/exec_amd64.s

@@ -0,0 +1,56 @@
+// Copyright (c) 2018 Timo Savola. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include "textflag.h"
+
+// func exec(textBase, stackLimit, memoryBase, memoryLimit, memoryGrowLimit, stackPtr uintptr)
+TEXT ·exec(SB),NOSPLIT,$0-48
+	MOVQ	textBase+0(FP), R12
+	MOVQ	stackLimit+8(FP), R13
+	MOVQ	memoryBase+16(FP), R14
+	MOVQ	memoryLimit+24(FP), R15
+	MOVQ	memoryGrowLimit+32(FP), BX
+	MOVQ	stackPtr+40(FP), CX
+
+	LEAQ	traphandler<>(SB), AX
+	MOVQ	AX, M0			// trap handler
+	MOVQ	BX, M1			// memory grow limit
+	MOVQ	CX, SP			// stack ptr
+
+	XORL	AX, AX
+	XORL	BX, BX
+	XORL	CX, CX
+	XORL	BP, BP
+	XORL	SI, SI
+	XORL	DI, DI
+	XORL	R8, R8
+	XORL	R9, R9			// suspend flag
+
+	MOVQ	R12, DX
+	ADDQ	$16, DX			// init code after trap trampoline
+	JMP	DX
+
+TEXT traphandler<>(SB),NOSPLIT,$0
+	CMPL	AX, $0			// exit trap (lower 32 bits)
+	JE	exittrap
+	ADDL	$100, AX		// 100 + trap id
+	JMP	sysexit
+
+exittrap:
+	SHRQ	$32, AX			// exit code (higher 32 bits)
+sysexit:
+	MOVL	AX, DI
+	MOVL	$231, AX		// exit_group syscall
+	SYSCALL
+
+TEXT ·callSys(SB),NOSPLIT,$0
+	MOVQ	R8, R9			// arg 6 (suspend flag)
+	MOVQ	DI, R8			// arg 5
+	MOVQ	SI, R10			// arg 4
+	MOVQ	BP, DX			// arg 3
+	MOVQ	BX, SI			// arg 2
+	MOVQ	CX, DI			// arg 1
+	SYSCALL
+	XORL	R9, R9			// suspend flag
+	RET

cmd/wasys/main.go

@@ -0,0 +1,173 @@
+// Copyright (c) 2018 Timo Savola. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+//go:generate go run ../../internal/cmd/syscalls/generate.go
+
+import (
+	"bytes"
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"os"
+	"reflect"
+	"syscall"
+	"unsafe"
+
+	"github.com/tsavola/wag"
+	"github.com/tsavola/wag/types"
+)
+
+var (
+	verbose = false
+)
+
+var importFuncs = make(map[string]uint64)
+
+type env struct{}
+
+func (*env) ImportFunction(module, field string, sig types.Function) (variadic bool, absAddr uint64, err error) {
+	if verbose {
+		log.Printf("import %s%s", field, sig)
+	}
+
+	if module != "env" {
+		err = fmt.Errorf("imported function's module is unknown: %s %s", module, field)
+		return
+	}
+
+	absAddr = importFuncs[field]
+	if absAddr == 0 {
+		err = fmt.Errorf("imported function not supported: %s %s", module, field)
+		return
+	}
+
+	return
+}
+
+func (*env) ImportGlobal(module, field string, t types.T) (valueBits uint64, err error) {
+	err = fmt.Errorf("imported global not supported: %s %s", module, field)
+	return
+}
+
+type fixedBuf struct {
+	b []byte
+}
+
+func (f *fixedBuf) Bytes() []byte { return f.b }
+func (f *fixedBuf) Grow(n int)    {}
+func (f *fixedBuf) Len() int      { return len(f.b) }
+
+func (f *fixedBuf) Write(b []byte) (n int, err error) {
+	offset := len(f.b)
+	n = len(b)
+	f.b = f.b[:len(f.b)+n]
+	copy(f.b[offset:], b)
+	return
+}
+
+func (f *fixedBuf) WriteByte(b byte) (err error) {
+	offset := len(f.b)
+	f.b = f.b[:offset+1]
+	f.b[offset] = b
+	return
+}
+
+func makeMem(size int, extraProt, extraFlags int) (mem []byte, err error) {
+	if size > 0 {
+		mem, err = syscall.Mmap(-1, 0, size, syscall.PROT_READ|syscall.PROT_WRITE|extraProt, syscall.MAP_PRIVATE|syscall.MAP_ANONYMOUS|extraFlags)
+	}
+	return
+}
+
+func memAddr(mem []byte) uintptr {
+	return (*reflect.SliceHeader)(unsafe.Pointer(&mem)).Data
+}
+
+func main() {
+	log.SetFlags(0)
+
+	flag.Usage = func() {
+		fmt.Fprintf(flag.CommandLine.Output(), "Usage: %s [options] wasmfile\n\n", os.Args[0])
+		fmt.Fprintf(flag.CommandLine.Output(), "Options:\n")
+		flag.PrintDefaults()
+	}
+
+	var (
+		textSize    = 128 * 1024 * 1024
+		roDataSize  = 4 * 1024 * 1024
+		stackSize   = 64 * 1024
+		entrySymbol = "main"
+	)
+
+	flag.BoolVar(&verbose, "v", verbose, "verbose logging")
+	flag.IntVar(&textSize, "textsize", textSize, "maximum program text size")
+	flag.IntVar(&roDataSize, "rodatasize", roDataSize, "maximum read-only data size")
+	flag.IntVar(&stackSize, "stacksize", stackSize, "call stack size")
+	flag.StringVar(&entrySymbol, "func", entrySymbol, "function to run")
+	flag.Parse()
+
+	if flag.NArg() != 1 {
+		flag.Usage()
+		os.Exit(2)
+	}
+	filename := flag.Arg(0)
+
+	prog, err := ioutil.ReadFile(filename)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	roDataMem, err := makeMem(roDataSize, 0, syscall.MAP_32BIT)
+	if err != nil {
+		log.Fatal(err)
+	}
+	roDataAddr := memAddr(roDataMem)
+
+	textMem, err := makeMem(textSize, syscall.PROT_EXEC, 0)
+	if err != nil {
+		log.Fatal(err)
+	}
+	textAddr := memAddr(textMem)
+	textBuf := &fixedBuf{textMem[:0]}
+
+	m := wag.Module{
+		EntrySymbol: entrySymbol,
+		EntryArgs:   make([]uint64, 2),
+	}
+	err = m.Load(bytes.NewReader(prog), &env{}, textBuf, roDataMem, int32(roDataAddr), nil)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	if err := syscall.Mprotect(roDataMem, syscall.PROT_READ); err != nil {
+		log.Fatal(err)
+	}
+
+	if err := syscall.Mprotect(textMem, syscall.PROT_EXEC); err != nil {
+		log.Fatal(err)
+	}
+
+	data, memoryOffset := m.Data()
+	initMemorySize, growMemorySize := m.MemoryLimits()
+	globalsMemoryMem, err := makeMem(memoryOffset+int(growMemorySize), 0, 0)
+	if err != nil {
+		log.Fatal(err)
+	}
+	copy(globalsMemoryMem, data)
+	memoryAddr := memAddr(globalsMemoryMem) + uintptr(memoryOffset)
+	initMemoryEnd := memoryAddr + uintptr(initMemorySize)
+	growMemoryEnd := memoryAddr + uintptr(growMemorySize)
+
+	stackMem, err := makeMem(stackSize, 0, syscall.MAP_STACK)
+	if err != nil {
+		log.Fatal(err)
+	}
+	stackAddr := memAddr(stackMem)
+	stackEnd := stackAddr + uintptr(stackSize)
+
+	exec(textAddr, stackAddr, memoryAddr, initMemoryEnd, growMemoryEnd, stackEnd)
+}

cmd/wasys/syscall.go

@@ -0,0 +1,137 @@
+// Generated by internal/cmd/syscalls/generate.go
+
+package main
+
+func importRead() uint64
+func importWrite() uint64
+func importOpen() uint64
+func importClose() uint64
+func importLseek() uint64
+func importPread() uint64
+func importPwrite() uint64
+func importAccess() uint64
+func importPipe() uint64
+func importDup() uint64
+func importDup2() uint64
+func importGetpid() uint64
+func importSendfile() uint64
+func importShutdown() uint64
+func importSocketpair() uint64
+func importFlock() uint64
+func importFsync() uint64
+func importFdatasync() uint64
+func importTruncate() uint64
+func importFtruncate() uint64
+func importGetcwd() uint64
+func importChdir() uint64
+func importFchdir() uint64
+func importRename() uint64
+func importMkdir() uint64
+func importRmdir() uint64
+func importCreat() uint64
+func importLink() uint64
+func importUnlink() uint64
+func importSymlink() uint64
+func importReadlink() uint64
+func importChmod() uint64
+func importFchmod() uint64
+func importChown() uint64
+func importFchown() uint64
+func importLchown() uint64
+func importUmask() uint64
+func importGetuid() uint64
+func importGetgid() uint64
+func importVhangup() uint64
+func importSync() uint64
+func importGettid() uint64
+func importTime() uint64
+func importPosixFadvise() uint64
+func importExit() uint64
+func importInotifyInit() uint64
+func importInotifyAddWatch() uint64
+func importInotifyRmWatch() uint64
+func importOpenat() uint64
+func importMkdirat() uint64
+func importFchownat() uint64
+func importUnlinkat() uint64
+func importRenameat() uint64
+func importLinkat() uint64
+func importSymlinkat() uint64
+func importReadlinkat() uint64
+func importFchmodat() uint64
+func importFaccessat() uint64
+func importSplice() uint64
+func importTee() uint64
+func importSyncFileRange() uint64
+func importFallocate() uint64
+func importEventfd() uint64
+func importDup3() uint64
+func importPipe2() uint64
+
+func init() {
+	importFuncs["read"] = importRead()
+	importFuncs["write"] = importWrite()
+	importFuncs["open"] = importOpen()
+	importFuncs["close"] = importClose()
+	importFuncs["lseek"] = importLseek()
+	importFuncs["pread"] = importPread()
+	importFuncs["pwrite"] = importPwrite()
+	importFuncs["access"] = importAccess()
+	importFuncs["pipe"] = importPipe()
+	importFuncs["dup"] = importDup()
+	importFuncs["dup2"] = importDup2()
+	importFuncs["getpid"] = importGetpid()
+	importFuncs["sendfile"] = importSendfile()
+	importFuncs["shutdown"] = importShutdown()
+	importFuncs["socketpair"] = importSocketpair()
+	importFuncs["flock"] = importFlock()
+	importFuncs["fsync"] = importFsync()
+	importFuncs["fdatasync"] = importFdatasync()
+	importFuncs["truncate"] = importTruncate()
+	importFuncs["ftruncate"] = importFtruncate()
+	importFuncs["getcwd"] = importGetcwd()
+	importFuncs["chdir"] = importChdir()
+	importFuncs["fchdir"] = importFchdir()
+	importFuncs["rename"] = importRename()
+	importFuncs["mkdir"] = importMkdir()
+	importFuncs["rmdir"] = importRmdir()
+	importFuncs["creat"] = importCreat()
+	importFuncs["link"] = importLink()
+	importFuncs["unlink"] = importUnlink()
+	importFuncs["symlink"] = importSymlink()
+	importFuncs["readlink"] = importReadlink()
+	importFuncs["chmod"] = importChmod()
+	importFuncs["fchmod"] = importFchmod()
+	importFuncs["chown"] = importChown()
+	importFuncs["fchown"] = importFchown()
+	importFuncs["lchown"] = importLchown()
+	importFuncs["umask"] = importUmask()
+	importFuncs["getuid"] = importGetuid()
+	importFuncs["getgid"] = importGetgid()
+	importFuncs["vhangup"] = importVhangup()
+	importFuncs["sync"] = importSync()
+	importFuncs["gettid"] = importGettid()
+	importFuncs["time"] = importTime()
+	importFuncs["posix_fadvise"] = importPosixFadvise()
+	importFuncs["_exit"] = importExit()
+	importFuncs["inotify_init"] = importInotifyInit()
+	importFuncs["inotify_add_watch"] = importInotifyAddWatch()
+	importFuncs["inotify_rm_watch"] = importInotifyRmWatch()
+	importFuncs["openat"] = importOpenat()
+	importFuncs["mkdirat"] = importMkdirat()
+	importFuncs["fchownat"] = importFchownat()
+	importFuncs["unlinkat"] = importUnlinkat()
+	importFuncs["renameat"] = importRenameat()
+	importFuncs["linkat"] = importLinkat()
+	importFuncs["symlinkat"] = importSymlinkat()
+	importFuncs["readlinkat"] = importReadlinkat()
+	importFuncs["fchmodat"] = importFchmodat()
+	importFuncs["faccessat"] = importFaccessat()
+	importFuncs["splice"] = importSplice()
+	importFuncs["tee"] = importTee()
+	importFuncs["sync_file_range"] = importSyncFileRange()
+	importFuncs["fallocate"] = importFallocate()
+	importFuncs["eventfd"] = importEventfd()
+	importFuncs["dup3"] = importDup3()
+	importFuncs["pipe2"] = importPipe2()
+}