wings/server/filesystem/errors.go

102 lines
2.7 KiB
Go

package filesystem
import (
"fmt"
"os"
"path/filepath"
"emperror.dev/errors"
"github.com/apex/log"
)
type ErrorCode string
const (
ErrCodeIsDirectory ErrorCode = "E_ISDIR"
ErrCodeDiskSpace ErrorCode = "E_NODISK"
ErrCodeUnknownArchive ErrorCode = "E_UNKNFMT"
ErrCodePathResolution ErrorCode = "E_BADPATH"
ErrCodeDenylistFile ErrorCode = "E_DENYLIST"
)
type Error struct {
code ErrorCode
path string
resolved string
}
// Returns a human-readable error string to identify the Error by.
func (e *Error) Error() string {
switch e.code {
case ErrCodeIsDirectory:
return "filesystem: is a directory"
case ErrCodeDiskSpace:
return "filesystem: not enough disk space"
case ErrCodeUnknownArchive:
return "filesystem: unknown archive format"
case ErrCodeDenylistFile:
r := e.resolved
if r == "" {
r = "<empty>"
}
return fmt.Sprintf("filesystem: file access prohibited: [%s] is on the denylist", r)
case ErrCodePathResolution:
r := e.resolved
if r == "" {
r = "<empty>"
}
return fmt.Sprintf("filesystem: server path [%s] resolves to a location outside the server root: %s", e.path, r)
}
return "filesystem: unhandled error type"
}
// Returns the ErrorCode for this specific error instance.
func (e *Error) Code() ErrorCode {
return e.code
}
// Checks if the given error is one of the Filesystem errors.
func IsFilesystemError(err error) (*Error, bool) {
var fserr *Error
if errors.As(err, &fserr) {
return fserr, true
}
return nil, false
}
// Checks if "err" is a filesystem Error type. If so, it will then drop in and check
// that the error code is the same as the provided ErrorCode passed in "code".
func IsErrorCode(err error, code ErrorCode) bool {
if e, ok := IsFilesystemError(err); ok {
return e.code == code
}
return false
}
// Returns a new BadPathResolution error.
func NewBadPathResolution(path string, resolved string) *Error {
return &Error{code: ErrCodePathResolution, path: path, resolved: resolved}
}
// Generates an error logger instance with some basic information.
func (fs *Filesystem) error(err error) *log.Entry {
return log.WithField("subsystem", "filesystem").WithField("root", fs.root).WithField("error", err)
}
// Handle errors encountered when walking through directories.
//
// If there is a path resolution error just skip the item entirely. Only return this for a
// directory, otherwise return nil. Returning this error for a file will stop the walking
// for the remainder of the directory. This is assuming an os.FileInfo struct was even returned.
func (fs *Filesystem) handleWalkerError(err error, f os.FileInfo) error {
if !IsErrorCode(err, ErrCodePathResolution) {
return err
}
if f != nil && f.IsDir() {
return filepath.SkipDir
}
return nil
}