1 files changed, 98 insertions, 0 deletions
diff --git a/libpod/network/cni/cni_exec.go b/libpod/network/cni/cni_exec.go
new file mode 100644
index 000000000..0aec3d4f1
--- /dev/null
+++ b/libpod/network/cni/cni_exec.go
@@ -0,0 +1,98 @@
+// Copyright 2016 CNI authors
+// Copyright 2021 Podman authors
+//
+// This code has been originally copied from github.com/containernetworking/cni
+// but has been changed to better fit the Podman use case.
+//
+// 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.
+
+// +build linux
+
+package cni
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"os/exec"
+	"path/filepath"
+
+	"github.com/containernetworking/cni/pkg/invoke"
+	"github.com/containernetworking/cni/pkg/version"
+)
+
+type cniExec struct {
+	version.PluginDecoder
+}
+
+type cniPluginError struct {
+	plugin  string
+	Code    uint   `json:"code"`
+	Msg     string `json:"msg"`
+	Details string `json:"details,omitempty"`
+}
+
+// Error returns a nicely formatted error message for the cni plugin errors.
+func (e *cniPluginError) Error() string {
+	err := fmt.Sprintf("cni plugin %s failed", e.plugin)
+	if e.Msg != "" {
+		err = fmt.Sprintf("%s: %s", err, e.Msg)
+	} else if e.Code > 0 {
+		err = fmt.Sprintf("%s with error code %d", err, e.Code)
+	}
+	if e.Details != "" {
+		err = fmt.Sprintf("%s: %s", err, e.Details)
+	}
+	return err
+}
+
+// ExecPlugin execute the cni plugin. Returns the stdout of the plugin or an error.
+func (e *cniExec) ExecPlugin(ctx context.Context, pluginPath string, stdinData []byte, environ []string) ([]byte, error) {
+	stdout := &bytes.Buffer{}
+	stderr := &bytes.Buffer{}
+	c := exec.CommandContext(ctx, pluginPath)
+	c.Env = environ
+	c.Stdin = bytes.NewBuffer(stdinData)
+	c.Stdout = stdout
+	c.Stderr = stderr
+
+	err := c.Run()
+	if err != nil {
+		return nil, annotatePluginError(err, pluginPath, stdout.Bytes(), stderr.Bytes())
+	}
+	return stdout.Bytes(), nil
+}
+
+// annotatePluginError parses the common cni plugin error json.
+func annotatePluginError(err error, plugin string, stdout []byte, stderr []byte) error {
+	pluginName := filepath.Base(plugin)
+	emsg := cniPluginError{
+		plugin: pluginName,
+	}
+	if len(stdout) == 0 {
+		if len(stderr) == 0 {
+			emsg.Msg = err.Error()
+		} else {
+			emsg.Msg = string(stderr)
+		}
+	} else if perr := json.Unmarshal(stdout, &emsg); perr != nil {
+		emsg.Msg = fmt.Sprintf("failed to unmarshal error message %q: %v", string(stdout), perr)
+	}
+	return &emsg
+}
+
+// FindInPath finds the plugin in the given paths.
+func (e *cniExec) FindInPath(plugin string, paths []string) (string, error) {
+	return invoke.FindInPath(plugin, paths)
+}