nvidia-container-toolkit/internal/oci/runtime_exec.go

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/*
# 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)
}