add panic handlers

client.go

@@ -5,6 +5,8 @@ import (
  "fmt"
  "math/rand"
  "net"
+ "os"
+ "runtime/debug"
  "strings"
  "time"
 
@@ -108,7 +110,7 @@ func applyOpts(options ...ClientOption) clientOpts {
  return conf
 }
 
-func (c *client) run(ctx context.Context, params *lookupParams) error {
+func (c *client) run(ctx context.Context, params *lookupParams) (err error) {
  ctx, cancel := context.WithCancel(ctx)
  done := make(chan struct{})
  go func() {
@@ -118,7 +120,7 @@ func (c *client) run(ctx context.Context, params *lookupParams) error {
 
  // If previous probe was ok, it should be fine now. In case of an error later on,
  // the entries' queue is closed.
- err := c.periodicQuery(ctx, params)
+ err = c.periodicQuery(ctx, params)
  cancel()
  <-done
  return err
@@ -165,6 +167,12 @@ var cleanupFreq = 10 * time.Second
 
 // Start listeners and waits for the shutdown signal from exit channel
 func (c *client) mainloop(ctx context.Context, params *lookupParams) {
+ defer func() {
+ if rerr := recover(); rerr != nil {
+ fmt.Fprintf(os.Stderr, "caught panic: %s\n%s\n", rerr, debug.Stack())
+ }
+ }()
+
  // start listening for responses
  msgCh := make(chan *dns.Msg, 32)
  if c.ipv4conn != nil {
@@ -313,6 +321,12 @@ func (c *client) shutdown() {
 // Data receiving routine reads from connection, unpacks packets into dns.Msg
 // structures and sends them to a given msgCh channel
 func (c *client) recv(ctx context.Context, l interface{}, msgCh chan *dns.Msg) {
+ defer func() {
+ if rerr := recover(); rerr != nil {
+ fmt.Fprintf(os.Stderr, "caught panic: %s\n%s\n", rerr, debug.Stack())
+ }
+ }()
+
  var readFrom func([]byte) (n int, src net.Addr, err error)
 
  switch pConn := l.(type) {
@@ -408,7 +422,14 @@ func (c *client) periodicQuery(ctx context.Context, params *lookupParams) error
 
 // Performs the actual query by service name (browse) or service instance name (lookup),
 // start response listeners goroutines and loops over the entries channel.
-func (c *client) query(params *lookupParams) error {
+func (c *client) query(params *lookupParams) (err error) {
+ defer func() {
+ if rerr := recover(); rerr != nil {
+ fmt.Fprintf(os.Stderr, "caught panic: %s\n%s\n", rerr, debug.Stack())
+ err = fmt.Errorf("panic in zeroconf query: %s", rerr)
+ }
+ }()
+
  var serviceName, serviceInstanceName string
  serviceName = fmt.Sprintf("%s.%s.", trimDot(params.Service), trimDot(params.Domain))
 

server.go

@@ -6,6 +6,7 @@ import (
  "math/rand"
  "net"
  "os"
+ "runtime/debug"
  "strings"
  "sync"
  "time"
@@ -309,7 +310,14 @@ func (s *Server) recv6(c *ipv6.PacketConn) {
 }
 
 // parsePacket is used to parse an incoming packet
-func (s *Server) parsePacket(packet []byte, ifIndex int, from net.Addr) error {
+func (s *Server) parsePacket(packet []byte, ifIndex int, from net.Addr) (err error) {
+ defer func() {
+ if rerr := recover(); rerr != nil {
+ fmt.Fprintf(os.Stderr, "caught panic: %s\n%s\n", rerr, debug.Stack())
+ err = fmt.Errorf("panic in mDNS packet handling: %s", rerr)
+ }
+ }()
+
  var msg dns.Msg
  if err := msg.Unpack(packet); err != nil {
  // log.Printf("[ERR] zeroconf: Failed to unpack packet: %v", err)
@@ -548,8 +556,14 @@ func (s *Server) serviceTypeName(resp *dns.Msg, ttl uint32) {
 }
 
 // Perform probing & announcement
-//TODO: implement a proper probing & conflict resolution
+// TODO: implement a proper probing & conflict resolution
 func (s *Server) probe() {
+ defer func() {
+ if rerr := recover(); rerr != nil {
+ fmt.Fprintf(os.Stderr, "caught panic: %s\n%s\n", rerr, debug.Stack())
+ }
+ }()
+
  defer s.refCount.Done()
 
  q := new(dns.Msg)