wasi: support converting more errors to wasi.Errno (#73)

Signed-off-by: Achille Roussel <[email protected]>

error_test.go

@@ -1,6 +1,13 @@
 package wasi_test
 
 import (
+	"context"
+	"fmt"
+	"io"
+	"io/fs"
+	"net"
+	"os"
+	"syscall"
 	"testing"
 
 	"github.com/stealthrocket/wasi-go"
@@ -17,3 +24,29 @@ func TestErrno(t *testing.T) {
 		})
 	}
 }
+
+func TestMakeErrno(t *testing.T) {
+	tests := []struct {
+		error error
+		errno wasi.Errno
+	}{
+		{nil, wasi.ESUCCESS},
+		{syscall.EAGAIN, wasi.EAGAIN},
+		{context.Canceled, wasi.ECANCELED},
+		{context.DeadlineExceeded, wasi.ETIMEDOUT},
+		{io.ErrUnexpectedEOF, wasi.EIO},
+		{fs.ErrClosed, wasi.EIO},
+		{net.ErrClosed, wasi.EIO},
+		{syscall.EPERM, wasi.EPERM},
+		{wasi.EAGAIN, wasi.EAGAIN},
+		{os.ErrDeadlineExceeded, wasi.ETIMEDOUT},
+	}
+
+	for _, test := range tests {
+		t.Run(fmt.Sprint(test.error), func(t *testing.T) {
+			if errno := wasi.MakeErrno(test.error); errno != test.errno {
+				t.Errorf("error mismatch: want=%d got=%d (%s)", test.errno, errno, errno)
+			}
+		})
+	}
+}

error_unix.go

@@ -4,6 +4,9 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"io"
+	"io/fs"
+	"net"
 	"syscall"
 )
 
@@ -18,22 +21,37 @@ func makeErrno(err error) Errno {
 }
 
 func makeErrnoSlow(err error) Errno {
-	if err == context.Canceled {
+	switch {
+	case errors.Is(err, context.Canceled):
 		return ECANCELED
+	case errors.Is(err, context.DeadlineExceeded):
+		return ETIMEDOUT
+	case errors.Is(err, io.ErrUnexpectedEOF),
+		errors.Is(err, fs.ErrClosed),
+		errors.Is(err, net.ErrClosed):
+		return EIO
 	}
+
 	var sysErrno syscall.Errno
 	if errors.As(err, &sysErrno) {
 		if sysErrno == 0 {
 			return ESUCCESS
 		}
 		return syscallErrnoToWASI(sysErrno)
 	}
+
+	var wasiErrno Errno
+	if errors.As(err, &wasiErrno) {
+		return wasiErrno
+	}
+
 	var timeout interface{ Timeout() bool }
 	if errors.As(err, &timeout) {
 		if timeout.Timeout() {
 			return ETIMEDOUT
 		}
 	}
+
 	panic(fmt.Errorf("unexpected error: %v", err))
 }