nvidia-container-toolkit/cmd/nvidia-cdi-hook/create-symlinks/create-symlinks.go
Evan Lezar d0d85a8c5c
Always use paths relative to the container root for links
This chagne ensures that we always treat the link path as a path
relative to the container root. Without this change, relative paths
in link paths would result links being created relative to the
current working directory where the hook is executed.

Signed-off-by: Evan Lezar <elezar@nvidia.com>
2024-10-29 12:16:51 -07:00

125 lines
3.1 KiB
Go

/**
# Copyright (c) 2022, 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 symlinks
import (
"fmt"
"os"
"path/filepath"
"strings"
"github.com/urfave/cli/v2"
"github.com/NVIDIA/nvidia-container-toolkit/internal/logger"
"github.com/NVIDIA/nvidia-container-toolkit/internal/oci"
)
type command struct {
logger logger.Interface
}
type config struct {
links cli.StringSlice
containerSpec string
}
// NewCommand constructs a hook command with the specified logger
func NewCommand(logger logger.Interface) *cli.Command {
c := command{
logger: logger,
}
return c.build()
}
// build creates the create-symlink command.
func (m command) build() *cli.Command {
cfg := config{}
c := cli.Command{
Name: "create-symlinks",
Usage: "A hook to create symlinks in the container.",
Action: func(c *cli.Context) error {
return m.run(c, &cfg)
},
}
c.Flags = []cli.Flag{
&cli.StringSliceFlag{
Name: "link",
Usage: "Specify a specific link to create. The link is specified as target::link",
Destination: &cfg.links,
},
// The following flags are testing-only flags.
&cli.StringFlag{
Name: "container-spec",
Usage: "Specify the path to the OCI container spec. If empty or '-' the spec will be read from STDIN. This is only intended for testing.",
Destination: &cfg.containerSpec,
Hidden: true,
},
}
return &c
}
func (m command) run(c *cli.Context, cfg *config) error {
s, err := oci.LoadContainerState(cfg.containerSpec)
if err != nil {
return fmt.Errorf("failed to load container state: %v", err)
}
containerRoot, err := s.GetContainerRoot()
if err != nil {
return fmt.Errorf("failed to determined container root: %v", err)
}
created := make(map[string]bool)
for _, l := range cfg.links.Value() {
if created[l] {
m.logger.Debugf("Link %v already processed", l)
continue
}
parts := strings.Split(l, "::")
if len(parts) != 2 {
m.logger.Warningf("Invalid link specification %v", l)
continue
}
err := m.createLink(containerRoot, parts[0], parts[1])
if err != nil {
m.logger.Warningf("Failed to create link %v: %v", parts, err)
}
created[l] = true
}
return nil
}
func (m command) createLink(containerRoot string, targetPath string, link string) error {
linkPath := filepath.Join(containerRoot, link)
m.logger.Infof("Symlinking %v to %v", linkPath, targetPath)
err := os.MkdirAll(filepath.Dir(linkPath), 0755)
if err != nil {
return fmt.Errorf("failed to create directory: %v", err)
}
err = os.Symlink(targetPath, linkPath)
if err != nil {
return fmt.Errorf("failed to create symlink: %v", err)
}
return nil
}