miracle091/dnscrypt-proxy
miracle091
/
dnscrypt-proxy
mirror of https://github.com/DNSCrypt/dnscrypt-proxy.git
1
0
Fork 0
Code Issues Releases Wiki Activity

Reduce the chances of corrupting the cache 

Write both parts of the cache to their temp files before renaming
Now only the 2nd rename failing can leave the cache in a bad state.
This commit is contained in:
William Elwood 2019-11-02 04:36:33 +00:00 committed by Frank Denis
parent b6d11b4351
commit 5ed7b7c24f
1 changed files with 22 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

32
dnscrypt-proxy/sources.go
View File

@ -79,22 +79,26 @@ func (source *Source) fetchFromCache(now time.Time) (delay time.Duration, err er
func (source *Source) writeToCache(bin, sig []byte) (err error) {
f := source.cacheFile
defer func() {
if err != nil {
if absPath, err2 := filepath.Abs(f); err2 == nil {
f = absPath
}
dlog.Warnf("%s: %s", f, err)
}
}()
if err = safefile.WriteFile(f, bin, 0644); err != nil {
var fSrc, fSig *safefile.File
if fSrc, err = safefile.Create(f, 0644); err != nil {
return
}
if err = safefile.WriteFile(f+".minisig", sig, 0644); err != nil {
defer fSrc.Close()
if fSig, err = safefile.Create(f+".minisig", 0644); err != nil {
return
}
defer fSig.Close()
if _, err = fSrc.Write(bin); err != nil {
return
}
if _, err = fSig.Write(sig); err != nil {
return
}
if err = fSrc.Commit(); err != nil {
return
}
return fSig.Commit()
}
func (source *Source) parseURLs(urls []string) {
for _, urlStr := range urls {
@ -155,7 +159,13 @@ func (source *Source) fetchWithCache(xTransport *XTransport, now time.Time) (del
return
}
source.in = bin
source.writeToCache(bin, sig) // ignore error: not fatal
if writeErr := source.writeToCache(bin, sig); writeErr != nil { // an error here isn't fatal
f := source.cacheFile
if absPath, absErr := filepath.Abs(f); absErr == nil {
f = absPath
}
dlog.Warnf("%s: %s", f, writeErr)
}
delay = source.prefetchDelay
return
}