better error handling for busy files; closes pterodactyl/panel#2332

This commit is contained in:
Dane Everitt 2020-09-15 19:53:00 -07:00
parent 6ba15e9884
commit ce76b9339e
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GPG Key ID: EEA66103B3D71F53
2 changed files with 43 additions and 4 deletions

View File

@ -339,10 +339,22 @@ func postServerDecompressFiles(c *gin.Context) {
}
if err := s.Filesystem.DecompressFile(data.RootPath, data.File); err != nil {
// Check if the file does not exist.
// NOTE: os.IsNotExist() does not work if the error is wrapped.
if errors.Is(err, os.ErrNotExist) {
c.Status(http.StatusNotFound)
c.AbortWithStatusJSON(http.StatusNotFound, gin.H{
"error": "The requested archive was not found.",
})
return
}
// If the file is busy for some reason just return a nicer error to the user since there is not
// much we specifically can do. They'll need to stop the running server process in order to overwrite
// a file like this.
if strings.Contains(err.Error(), "text file busy") {
s.Log().WithField("error", err).Warn("failed to decompress file due to busy text file")
c.AbortWithStatusJSON(http.StatusBadRequest, gin.H{
"error": "One or more files this archive is attempting to overwrite are currently in use by another process. Please try again.",
})
return
}

View File

@ -400,9 +400,10 @@ func (fs *Filesystem) Writefile(p string, r io.Reader) error {
currentSize = stat.Size()
}
o := &fileOpener{}
// This will either create the file if it does not already exist, or open and
// truncate the existing file.
file, err := os.OpenFile(cleaned, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644)
file, err := o.open(cleaned, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644)
if err != nil {
return errors.WithStack(err)
}
@ -937,3 +938,29 @@ func (fs *Filesystem) handleWalkerError(err error, f os.FileInfo) error {
return nil
}
type fileOpener struct {
busy uint
}
// Attempts to open a given file up to "attempts" number of times, using a backoff. If the file
// cannot be opened because of a "text file busy" error, we will attempt until the number of attempts
// has been exhaused, at which point we will abort with an error.
func (fo *fileOpener) open(path string, flags int, perm os.FileMode) (*os.File, error) {
for {
f, err := os.OpenFile(path, flags, perm)
// If there is an error because the text file is busy, go ahead and sleep for a few
// hundred milliseconds and then try again up to three times before just returning the
// error back to the caller.
//
// Based on code from: https://github.com/golang/go/issues/22220#issuecomment-336458122
if err != nil && fo.busy < 3 && strings.Contains(err.Error(), "text file busy") {
time.Sleep(100 * time.Millisecond << fo.busy)
fo.busy++
continue
}
return f, err
}
}