nvidia-container-toolkit/internal/lookup/symlinks.go
Evan Lezar 927ec78b6e Add symlinks package with Resolve function
This change adds a symlinks.Resolve function for resolving symlinks and
updates usages across the code to make use of it.

Signed-off-by: Evan Lezar <elezar@nvidia.com>
2023-05-23 20:42:17 +02:00

120 lines
3.1 KiB
Go

/**
# 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 lookup
import (
"fmt"
"path/filepath"
"github.com/NVIDIA/nvidia-container-toolkit/internal/lookup/symlinks"
"github.com/sirupsen/logrus"
)
type symlinkChain struct {
file
}
type symlink struct {
file
}
// NewSymlinkChainLocator creats a locator that can be used for locating files through symlinks.
// A logger can also be specified.
func NewSymlinkChainLocator(logger *logrus.Logger, root string) Locator {
f := newFileLocator(WithLogger(logger), WithRoot(root))
l := symlinkChain{
file: *f,
}
return &l
}
// NewSymlinkLocator creats a locator that can be used for locating files through symlinks.
// A logger can also be specified.
func NewSymlinkLocator(logger *logrus.Logger, root string) Locator {
f := newFileLocator(WithLogger(logger), WithRoot(root))
l := symlink{
file: *f,
}
return &l
}
// Locate finds the specified pattern at the specified root.
// If the file is a symlink, the link is followed and all candidates to the final target are returned.
func (p symlinkChain) Locate(pattern string) ([]string, error) {
candidates, err := p.file.Locate(pattern)
if err != nil {
return nil, err
}
if len(candidates) == 0 {
return candidates, nil
}
found := make(map[string]bool)
for len(candidates) > 0 {
candidate := candidates[0]
candidates = candidates[:len(candidates)-1]
if found[candidate] {
continue
}
found[candidate] = true
target, err := symlinks.Resolve(candidate)
if err != nil {
return nil, fmt.Errorf("error resolving symlink: %v", err)
}
if !filepath.IsAbs(target) {
target, err = filepath.Abs(filepath.Join(filepath.Dir(candidate), target))
if err != nil {
return nil, fmt.Errorf("failed to construct absolute path: %v", err)
}
}
p.logger.Debugf("Resolved link: '%v' => '%v'", candidate, target)
if !found[target] {
candidates = append(candidates, target)
}
}
var filenames []string
for f := range found {
filenames = append(filenames, f)
}
return filenames, nil
}
// Locate finds the specified pattern at the specified root.
// If the file is a symlink, the link is resolved and the target returned.
func (p symlink) Locate(pattern string) ([]string, error) {
candidates, err := p.file.Locate(pattern)
if err != nil {
return nil, err
}
if len(candidates) != 1 {
return nil, fmt.Errorf("failed to uniquely resolve symlink %v: %v", pattern, candidates)
}
target, err := filepath.EvalSymlinks(candidates[0])
if err != nil {
return nil, fmt.Errorf("failed to resolve link: %v", err)
}
return []string{target}, err
}