Check in gVisor.

PiperOrigin-RevId: 194583126
Change-Id: Ica1d8821a90f74e7e745962d71801c598c652463

1 files changed, 76 insertions, 0 deletions

diff --git a/pkg/abi/flag.go b/pkg/abi/flag.go
new file mode 100644
index 000000000..0391ccf37
--- /dev/null
+++ b/pkg/abi/flag.go
@@ -0,0 +1,76 @@
+// Copyright 2018 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package abi
+
+import (
+	"fmt"
+	"math"
+	"strconv"
+	"strings"
+)
+
+// A FlagSet is a slice of bit-flags and their name.
+type FlagSet []struct {
+	Flag uint64
+	Name string
+}
+
+// Parse returns a pretty version of val, using the flag names for known flags.
+// Unknown flags remain numeric.
+func (s FlagSet) Parse(val uint64) string {
+	var flags []string
+
+	for _, f := range s {
+		if val&f.Flag == f.Flag {
+			flags = append(flags, f.Name)
+			val &^= f.Flag
+		}
+	}
+
+	if val != 0 {
+		flags = append(flags, "0x"+strconv.FormatUint(val, 16))
+	}
+
+	return strings.Join(flags, "|")
+}
+
+// ValueSet is a slice of syscall values and their name. Parse will replace
+// values that exactly match an entry with its name.
+type ValueSet []struct {
+	Value uint64
+	Name  string
+}
+
+// Parse returns the name of the value associated with `val`. Unknown values
+// are converted to hex.
+func (e ValueSet) Parse(val uint64) string {
+	for _, f := range e {
+		if val == f.Value {
+			return f.Name
+		}
+	}
+	return fmt.Sprintf("%#x", val)
+}
+
+// ParseName returns the flag value associated with 'name'. Returns false
+// if no value is found.
+func (e ValueSet) ParseName(name string) (uint64, bool) {
+	for _, f := range e {
+		if name == f.Name {
+			return f.Value, true
+		}
+	}
+	return math.MaxUint64, false
+}