diff options
Diffstat (limited to 'plugin/hosts/hostsfile.go')
| -rw-r--r-- | plugin/hosts/hostsfile.go | 151 |
1 files changed, 81 insertions, 70 deletions
diff --git a/plugin/hosts/hostsfile.go b/plugin/hosts/hostsfile.go index dbbc283b2..4b912b17c 100644 --- a/plugin/hosts/hostsfile.go +++ b/plugin/hosts/hostsfile.go @@ -19,8 +19,6 @@ import ( "github.com/coredns/coredns/plugin" ) -const cacheMaxAge = 5 * time.Second - func parseLiteralIP(addr string) net.IP { if i := strings.Index(addr, "%"); i >= 0 { // discard ipv6 zone @@ -34,13 +32,7 @@ func absDomainName(b string) string { return plugin.Name(b).Normalize() } -// Hostsfile contains known host entries. -type Hostsfile struct { - sync.RWMutex - - // list of zones we are authoritive for - Origins []string - +type hostsMap struct { // Key for the list of literal IP addresses must be a host // name. It would be part of DNS labels, a FQDN or an absolute // FQDN. @@ -52,71 +44,80 @@ type Hostsfile struct { // including IPv6 address with zone identifier. // We don't support old-classful IP address notation. byAddr map[string][]string +} - // inline saves the hosts file is inlined in Corefile - // We need a copy here as we want to use inline to override - // the default /etc/hosts - inline []string - - expire time.Time - path string - mtime time.Time - size int64 +func newHostsMap() *hostsMap { + return &hostsMap{ + byNameV4: make(map[string][]net.IP), + byNameV6: make(map[string][]net.IP), + byAddr: make(map[string][]string), + } } -// ReadHosts determines if the cached data needs to be updated based on the size and modification time of the hostsfile. -func (h *Hostsfile) ReadHosts() { - now := time.Now() +// Hostsfile contains known host entries. +type Hostsfile struct { + sync.RWMutex - // Not deferring h.RUnlock() because we may need to remove the read lock and aquire a write lock - h.RLock() - if now.Before(h.expire) && len(h.byAddr) > 0 { - h.RUnlock() - return - } - stat, err := os.Stat(h.path) - if err == nil && h.mtime.Equal(stat.ModTime()) && h.size == stat.Size() { - h.RUnlock() - h.Lock() - h.expire = now.Add(cacheMaxAge) - h.Unlock() + // list of zones we are authoritive for + Origins []string + + // hosts maps for lookups + hmap *hostsMap + + // inline saves the hosts file that is inlined in a Corefile. + // We need a copy here as we want to use it to initialize the maps for parse. + inline *hostsMap + + // path to the hosts file + path string + + // mtime and size are only read and modified by a single goroutine + mtime time.Time + size int64 +} + +// readHosts determines if the cached data needs to be updated based on the size and modification time of the hostsfile. +func (h *Hostsfile) readHosts() { + file, err := os.Open(h.path) + if err != nil { + // We already log a warning if the file doesn't exist or can't be opened on setup. No need to return the error here. return } + defer file.Close() - var file *os.File - if file, _ = os.Open(h.path); file == nil { - // If this is the first time then we will try to parse inline - if len(h.byAddr) == 0 && len(h.inline) > 0 { - h.Parse(nil) - } - h.RUnlock() + stat, err := file.Stat() + if err == nil && h.mtime.Equal(stat.ModTime()) && h.size == stat.Size() { return } - defer file.Close() - h.RUnlock() h.Lock() defer h.Unlock() - h.Parse(file) + h.parseReader(file) // Update the data cache. - h.expire = now.Add(cacheMaxAge) h.mtime = stat.ModTime() h.size = stat.Size() } -// Parse reads the hostsfile and populates the byName and byAddr maps. -func (h *Hostsfile) Parse(file io.Reader) { - hsv4 := make(map[string][]net.IP) - hsv6 := make(map[string][]net.IP) - is := make(map[string][]string) - - var readers []io.Reader - if file != nil { - readers = append(readers, file) +func (h *Hostsfile) initInline(inline []string) { + if len(inline) == 0 { + return } - readers = append(readers, strings.NewReader(strings.Join(h.inline, "\n"))) - scanner := bufio.NewScanner(io.MultiReader(readers...)) + + hmap := newHostsMap() + h.inline = h.parse(strings.NewReader(strings.Join(inline, "\n")), hmap) + *h.hmap = *h.inline +} + +func (h *Hostsfile) parseReader(r io.Reader) { + h.hmap = h.parse(r, h.inline) +} + +// Parse reads the hostsfile and populates the byName and byAddr maps. +func (h *Hostsfile) parse(r io.Reader, override *hostsMap) *hostsMap { + hmap := newHostsMap() + + scanner := bufio.NewScanner(r) for scanner.Scan() { line := scanner.Bytes() if i := bytes.Index(line, []byte{'#'}); i >= 0 { @@ -140,18 +141,31 @@ func (h *Hostsfile) Parse(file io.Reader) { } switch ver { case 4: - hsv4[name] = append(hsv4[name], addr) + hmap.byNameV4[name] = append(hmap.byNameV4[name], addr) case 6: - hsv6[name] = append(hsv6[name], addr) + hmap.byNameV6[name] = append(hmap.byNameV6[name], addr) default: continue } - is[addr.String()] = append(is[addr.String()], name) + hmap.byAddr[addr.String()] = append(hmap.byAddr[addr.String()], name) } } - h.byNameV4 = hsv4 - h.byNameV6 = hsv6 - h.byAddr = is + + if override == nil { + return hmap + } + + for name := range override.byNameV4 { + hmap.byNameV4[name] = append(hmap.byNameV4[name], override.byNameV4[name]...) + } + for name := range override.byNameV4 { + hmap.byNameV6[name] = append(hmap.byNameV6[name], override.byNameV6[name]...) + } + for addr := range override.byAddr { + hmap.byAddr[addr] = append(hmap.byAddr[addr], override.byAddr[addr]...) + } + + return hmap } // ipVersion returns what IP version was used textually @@ -169,11 +183,10 @@ func ipVersion(s string) int { // LookupStaticHostV4 looks up the IPv4 addresses for the given host from the hosts file. func (h *Hostsfile) LookupStaticHostV4(host string) []net.IP { - h.ReadHosts() h.RLock() defer h.RUnlock() - if len(h.byNameV4) != 0 { - if ips, ok := h.byNameV4[absDomainName(host)]; ok { + if len(h.hmap.byNameV4) != 0 { + if ips, ok := h.hmap.byNameV4[absDomainName(host)]; ok { ipsCp := make([]net.IP, len(ips)) copy(ipsCp, ips) return ipsCp @@ -184,11 +197,10 @@ func (h *Hostsfile) LookupStaticHostV4(host string) []net.IP { // LookupStaticHostV6 looks up the IPv6 addresses for the given host from the hosts file. func (h *Hostsfile) LookupStaticHostV6(host string) []net.IP { - h.ReadHosts() h.RLock() defer h.RUnlock() - if len(h.byNameV6) != 0 { - if ips, ok := h.byNameV6[absDomainName(host)]; ok { + if len(h.hmap.byNameV6) != 0 { + if ips, ok := h.hmap.byNameV6[absDomainName(host)]; ok { ipsCp := make([]net.IP, len(ips)) copy(ipsCp, ips) return ipsCp @@ -199,15 +211,14 @@ func (h *Hostsfile) LookupStaticHostV6(host string) []net.IP { // LookupStaticAddr looks up the hosts for the given address from the hosts file. func (h *Hostsfile) LookupStaticAddr(addr string) []string { - h.ReadHosts() h.RLock() defer h.RUnlock() addr = parseLiteralIP(addr).String() if addr == "" { return nil } - if len(h.byAddr) != 0 { - if hosts, ok := h.byAddr[addr]; ok { + if len(h.hmap.byAddr) != 0 { + if hosts, ok := h.hmap.byAddr[addr]; ok { hostsCp := make([]string, len(hosts)) copy(hostsCp, hosts) return hostsCp |