提交 4cd86a10 编写于 作者: E Evan Lezar

Add a Runtime internface to the oci pacakge

This change adds a Runtime interface to the oci package.
A single method, Exec, accepts a list of arguments as a
string slice and returns an error.

A SyscallExec Runtime is provided as an implementation that forwards
the passed arguments to a specified command through
syscall.Exec.
Signed-off-by: NEvan Lezar <elezar@nvidia.com>
上级 22ca74d4
/*
# Copyright (c) 2021, NVIDIA CORPORATION. All rights reserved.
#
# 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 oci
// Runtime is an interface for a runtime shim. The Exec method accepts a list
// of command line arguments, and returns an error / nil.
type Runtime interface {
Exec([]string) error
}
/*
# Copyright (c) 2021, NVIDIA CORPORATION. All rights reserved.
#
# 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 oci
import (
"fmt"
"os"
"syscall"
log "github.com/sirupsen/logrus"
)
// SyscallExecRuntime wraps the path that a binary and defines the semanitcs for how to exec into it.
// This can be used to wrap an OCI-compliant low-level runtime binary, allowing it to be used through the
// Runtime internface.
type SyscallExecRuntime struct {
logger *log.Logger
path string
// exec is used for testing. This defaults to syscall.Exec
exec func(argv0 string, argv []string, envv []string) error
}
var _ Runtime = (*SyscallExecRuntime)(nil)
// NewSyscallExecRuntime creates a SyscallExecRuntime for the specified path with the standard logger
func NewSyscallExecRuntime(path string) (Runtime, error) {
return NewSyscallExecRuntimeWithLogger(log.StandardLogger(), path)
}
// NewSyscallExecRuntimeWithLogger creates a SyscallExecRuntime for the specified logger and path
func NewSyscallExecRuntimeWithLogger(logger *log.Logger, path string) (Runtime, error) {
info, err := os.Stat(path)
if err != nil {
return nil, fmt.Errorf("invalid path '%v': %v", path, err)
}
if info.IsDir() || info.Mode()&0111 == 0 {
return nil, fmt.Errorf("specified path '%v' is not an executable file", path)
}
shim := SyscallExecRuntime{
logger: logger,
path: path,
exec: syscall.Exec,
}
return &shim, nil
}
// Exec exces into the binary at the path from the SyscallExecRuntime struct, passing it the supplied arguments
// after ensuring that the first argument is the path of the target binary.
func (s SyscallExecRuntime) Exec(args []string) error {
runtimeArgs := []string{s.path}
if len(args) > 1 {
runtimeArgs = append(runtimeArgs, args[1:]...)
}
err := s.exec(s.path, runtimeArgs, os.Environ())
if err != nil {
return fmt.Errorf("could not exec '%v': %v", s.path, err)
}
// syscall.Exec is not expected to return. This is an error state regardless of whether
// err is nil or not.
return fmt.Errorf("unexpected return from exec '%v'", s.path)
}
/*
# Copyright (c) 2021, NVIDIA CORPORATION. All rights reserved.
#
# 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 oci
import (
"fmt"
"strings"
"testing"
testlog "github.com/sirupsen/logrus/hooks/test"
"github.com/stretchr/testify/require"
)
func TestSyscallExecConstructor(t *testing.T) {
r, err := NewSyscallExecRuntime("////an/invalid/path")
require.Error(t, err)
require.Nil(t, r)
r, err = NewSyscallExecRuntime("/tmp")
require.Error(t, err)
require.Nil(t, r)
r, err = NewSyscallExecRuntime("/dev/null")
require.Error(t, err)
require.Nil(t, r)
r, err = NewSyscallExecRuntime("/bin/sh")
require.NoError(t, err)
f, ok := r.(*SyscallExecRuntime)
require.True(t, ok)
require.Equal(t, "/bin/sh", f.path)
}
func TestSyscallExecForwardsArgs(t *testing.T) {
logger, _ := testlog.NewNullLogger()
f := SyscallExecRuntime{
logger: logger,
path: "runtime",
}
testCases := []struct {
returnError error
args []string
errorPrefix string
}{
{
returnError: nil,
errorPrefix: "unexpected return from exec",
},
{
returnError: fmt.Errorf("error from exec"),
errorPrefix: "could not exec",
},
{
returnError: nil,
args: []string{"otherargv0"},
errorPrefix: "unexpected return from exec",
},
{
returnError: nil,
args: []string{"otherargv0", "arg1", "arg2", "arg3"},
errorPrefix: "unexpected return from exec",
},
}
for i, tc := range testCases {
execMock := WithMockExec(f, tc.returnError)
err := execMock.Exec(tc.args)
require.Errorf(t, err, "%d: %v", i, tc)
require.Truef(t, strings.HasPrefix(err.Error(), tc.errorPrefix), "%d: %v", i, tc)
if tc.returnError != nil {
require.Truef(t, strings.HasSuffix(err.Error(), tc.returnError.Error()), "%d: %v", i, tc)
}
require.Equalf(t, f.path, execMock.argv0, "%d: %v", i, tc)
require.Equalf(t, f.path, execMock.argv[0], "%d: %v", i, tc)
require.LessOrEqualf(t, len(tc.args), len(execMock.argv), "%d: %v", i, tc)
if len(tc.args) > 1 {
require.Equalf(t, tc.args[1:], execMock.argv[1:], "%d: %v", i, tc)
}
}
}
/*
# Copyright (c) 2021, NVIDIA CORPORATION. All rights reserved.
#
# 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 oci
// MockExecRuntime wraps a SyscallExecRuntime, intercepting the exec call for testing
type MockExecRuntime struct {
SyscallExecRuntime
execMock
}
// WithMockExec wraps a specified SyscallExecRuntime with a mocked exec function for testing
func WithMockExec(e SyscallExecRuntime, execResult error) *MockExecRuntime {
m := MockExecRuntime{
SyscallExecRuntime: e,
execMock: execMock{result: execResult},
}
// overrdie the exec function to the mocked exec function.
m.SyscallExecRuntime.exec = m.execMock.exec
return &m
}
type execMock struct {
argv0 string
argv []string
envv []string
result error
}
func (m *execMock) exec(argv0 string, argv []string, envv []string) error {
m.argv0 = argv0
m.argv = argv
m.envv = envv
return m.result
}
Markdown is supported
0% .
You are about to add 0 people to the discussion. Proceed with caution.
先完成此消息的编辑!
想要评论请 注册