87 lines
2.5 KiB
Go
87 lines
2.5 KiB
Go
package utils
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import (
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"crypto/rand"
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"encoding/hex"
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"encoding/json"
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"io"
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"os"
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"path/filepath"
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"syscall"
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)
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const (
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exitSignalOffset = 128
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)
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// GenerateRandomName returns a new name joined with a prefix. This size
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// specified is used to truncate the randomly generated value
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func GenerateRandomName(prefix string, size int) (string, error) {
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id := make([]byte, 32)
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if _, err := io.ReadFull(rand.Reader, id); err != nil {
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return "", err
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}
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if size > 64 {
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size = 64
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}
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return prefix + hex.EncodeToString(id)[:size], nil
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}
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// ResolveRootfs ensures that the current working directory is
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// not a symlink and returns the absolute path to the rootfs
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func ResolveRootfs(uncleanRootfs string) (string, error) {
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rootfs, err := filepath.Abs(uncleanRootfs)
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if err != nil {
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return "", err
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}
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return filepath.EvalSymlinks(rootfs)
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}
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// ExitStatus returns the correct exit status for a process based on if it
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// was signaled or exited cleanly
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func ExitStatus(status syscall.WaitStatus) int {
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if status.Signaled() {
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return exitSignalOffset + int(status.Signal())
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}
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return status.ExitStatus()
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}
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// WriteJSON writes the provided struct v to w using standard json marshaling
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func WriteJSON(w io.Writer, v interface{}) error {
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data, err := json.Marshal(v)
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if err != nil {
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return err
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}
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_, err = w.Write(data)
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return err
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}
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// CleanPath makes a path safe for use with filepath.Join. This is done by not
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// only cleaning the path, but also (if the path is relative) adding a leading
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// '/' and cleaning it (then removing the leading '/'). This ensures that a
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// path resulting from prepending another path will always resolve to lexically
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// be a subdirectory of the prefixed path. This is all done lexically, so paths
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// that include symlinks won't be safe as a result of using CleanPath.
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func CleanPath(path string) string {
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// Deal with empty strings nicely.
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if path == "" {
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return ""
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}
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// Ensure that all paths are cleaned (especially problematic ones like
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// "/../../../../../" which can cause lots of issues).
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path = filepath.Clean(path)
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// If the path isn't absolute, we need to do more processing to fix paths
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// such as "../../../../<etc>/some/path". We also shouldn't convert absolute
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// paths to relative ones.
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if !filepath.IsAbs(path) {
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path = filepath.Clean(string(os.PathSeparator) + path)
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// This can't fail, as (by definition) all paths are relative to root.
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path, _ = filepath.Rel(string(os.PathSeparator), path)
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}
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// Clean the path again for good measure.
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return filepath.Clean(path)
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}
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