cmd/land: support hello world

This commit is contained in:
Cadey Ratio 2018-06-07 17:08:00 -07:00
parent 9e6738969a
commit 2af7287ace
2 changed files with 84 additions and 13 deletions

View File

@ -1,3 +1,50 @@
package main
func main() {}
import (
"context"
"flag"
"os"
"github.com/Xe/ln"
)
func main() {
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
flag.Parse()
if flag.NArg() != 1 {
ln.Fatal(ctx, ln.Info("please pass a webassembly file to run"))
}
fname := flag.Arg(0)
fin, err := os.Open(fname)
if err != nil {
ln.FatalErr(ctx, err, ln.F{"msg": "can't open file", "fname": fname})
}
defer fin.Close()
p, err := NewProcess(fin)
if err != nil {
ln.FatalErr(ctx, err, ln.F{"msg": "can't create process", "fname": fname})
}
foundMain := false
mainID := uint32(0)
for name, entry := range p.mod.Export.Entries {
if name == "main" && entry.FieldStr == "main" {
mainID = entry.Index
foundMain = true
break
}
}
if !foundMain {
ln.Fatal(ctx, ln.F{"msg": "no main function exported"})
}
_, err = p.vm.ExecCode(int64(mainID))
if err != nil {
ln.FatalErr(ctx, err)
}
}

View File

@ -2,31 +2,50 @@ package main
import (
gcontext "context"
"errors"
"io"
"os"
"reflect"
"github.com/Xe/ln"
"github.com/Xe/uuid"
"github.com/go-interpreter/wagon/exec"
"github.com/go-interpreter/wagon/validate"
"github.com/go-interpreter/wagon/wasm"
)
// Process is a larger level wrapper around a webassembly VM that gives it
// system call access.
type Process struct {
id string
vm *exec.VM
id int32
vm *exec.VM
mod *wasm.Module
}
func NewProcess(vm *exec.VM) *Process {
p := &Process{
id: uuid.New(),
vm: vm,
// NewProcess constructs a new webassembly process based on the input webassembly module as a reader.
func NewProcess(fin io.Reader) (*Process, error) {
p := &Process{}
mod, err := wasm.ReadModule(fin, p.importer)
if err != nil {
return nil, err
}
return p
if mod.Memory == nil {
return nil, errors.New("must declare a memory, sorry :(")
}
vm, err := exec.NewVM(mod)
if err != nil {
return nil, err
}
p.mod = mod
p.vm = vm
return p, nil
}
func (p Process) importer(name string) (*wasm.Module, error) {
func (p *Process) importer(name string) (*wasm.Module, error) {
switch name {
case "env":
m := wasm.NewModule()
@ -78,14 +97,19 @@ func (p Process) importer(name string) (*wasm.Module, error) {
}
}
// ID returns the process ID string.
func (p Process) ID() string { return p.id }
// ID returns the process ID.
func (p Process) ID() int32 { return p.id }
// VM returns the webassembly VM used to execute code. This isn't thread-safe.
func (p Process) VM() *exec.VM { return p.vm }
func (p *Process) log(ptr int32, len int32) int32 {
data := p.vm.Memory()[ptr : ptr+len]
mem := p.vm.Memory()
if mem == nil {
panic("memory is nil, wtf")
}
data := mem[ptr : ptr+len]
ln.Log(gcontext.Background(), ln.F{"data": data, "data_string": string(data), "pid": p.id})
return 0