pkg/ipc: pass only exec encoding to Exec

Does not require passing text program to ipc.Env.Exec.
Make it possible to provide just the exec encoding.
This requires moving fallback coverage to the host
since it need the program.

2 files changed, 7 insertions, 7 deletions

diff --git a/prog/encodingexec.go b/prog/encodingexec.go
index 40cfc9592..fb8e5fbaf 100644
--- a/prog/encodingexec.go
+++ b/prog/encodingexec.go
@@ -23,7 +23,6 @@ package prog
 
 import (
 	"encoding/binary"
-	"errors"
 	"fmt"
 	"reflect"
 	"sort"
@@ -63,8 +62,6 @@ const (
 	execMaxCommands = 1000 // executor knows about this constant (kMaxCommands)
 )
 
-var ErrExecBufferTooSmall = errors.New("encodingexec: provided buffer is too small")
-
 // SerializeForExec serializes program p for execution by process pid into the provided buffer.
 // Returns number of bytes written to the buffer.
 // If the provided buffer is too small for the program an error is returned.
@@ -81,8 +78,11 @@ func (p *Prog) SerializeForExec() ([]byte, error) {
 		w.serializeCall(c)
 	}
 	w.write(execInstrEOF)
-	if len(w.buf) > ExecBufferSize || w.copyoutSeq > execMaxCommands {
-		return nil, ErrExecBufferTooSmall
+	if len(w.buf) > ExecBufferSize {
+		return nil, fmt.Errorf("encodingexec: too large program (%v/%v)", len(w.buf), ExecBufferSize)
+	}
+	if w.copyoutSeq > execMaxCommands {
+		return nil, fmt.Errorf("encodingexec: too many resources (%v/%v)", w.copyoutSeq, execMaxCommands)
 	}
 	return w.buf, nil
 }
diff --git a/prog/encodingexec_test.go b/prog/encodingexec_test.go
index 357cca18b..5dfcbd0e3 100644
--- a/prog/encodingexec_test.go
+++ b/prog/encodingexec_test.go
@@ -752,8 +752,8 @@ func TestSerializeForExecOverflow(t *testing.T) {
 				t.Fatal(err)
 			}
 			_, err = p.SerializeForExec()
-			if test.overflow && err != ErrExecBufferTooSmall {
-				t.Fatalf("want overflow but got %v", err)
+			if test.overflow && err == nil {
+				t.Fatalf("want overflow but got no error")
 			}
 			if !test.overflow && err != nil {
 				t.Fatalf("want no overflow but got %v", err)