extend --profile cmd line option to allow interface to be specified

Closes #691

config.go

@@ -126,7 +126,7 @@ type config struct {
 	SimNet               bool          `long:"simnet" description:"Use the simulation test network"`
 	DisableCheckpoints   bool          `long:"nocheckpoints" description:"Disable built-in checkpoints.  Don't do this unless you know what you're doing."`
 	DbType               string        `long:"dbtype" description:"Database backend to use for the Block Chain"`
-	Profile              string        `long:"profile" description:"Enable HTTP profiling on given port -- NOTE port must be between 1024 and 65536"`
+	Profile              string        `long:"profile" description:"Enable HTTP profiling on given [addr:]port -- NOTE port must be between 1024 and 65536"`
 	CPUProfile           string        `long:"cpuprofile" description:"Write CPU profile to the specified file"`
 	MemProfile           string        `long:"memprofile" description:"Write mem profile to the specified file"`
 	DumpBlockchain       string        `long:"dumpblockchain" description:"Write blockchain as a flat file of blocks for use with addblock, to the specified filename"`
@@ -636,12 +636,27 @@ func loadConfig() (*config, []string, error) {
 		return nil, nil, err
 	}
 
-	// Validate profile port number
+	// Validate format of profile, can be an address:port, or just a port.
 	if cfg.Profile != "" {
-		profilePort, err := strconv.Atoi(cfg.Profile)
-		if err != nil || profilePort < 1024 || profilePort > 65535 {
-			str := "%s: the profile port must be between 1024 and 65535"
-			err := fmt.Errorf(str, funcName)
+		// if profile is just a number, then add a default host of "127.0.0.1" such that Profile is a valid tcp address
+		if _, err := strconv.Atoi(cfg.Profile); err == nil {
+			cfg.Profile = net.JoinHostPort("127.0.0.1", cfg.Profile)
+		}
+
+		// check the Profile is a valid address
+		_, portStr, err := net.SplitHostPort(cfg.Profile)
+		if err != nil {
+			str := "%s: profile: %s"
+			err := fmt.Errorf(str, funcName, err)
+			fmt.Fprintln(os.Stderr, err)
+			fmt.Fprintln(os.Stderr, usageMessage)
+			return nil, nil, err
+		}
+
+		// finally, check the port is in range
+		if port, _ := strconv.Atoi(portStr); port < 1024 || port > 65535 {
+			str := "%s: profile: address %s: port must be between 1024 and 65535"
+			err := fmt.Errorf(str, funcName, cfg.Profile)
 			fmt.Fprintln(os.Stderr, err)
 			fmt.Fprintln(os.Stderr, usageMessage)
 			return nil, nil, err

dcrd.go

@@ -7,7 +7,6 @@ package main
 
 import (
 	"fmt"
-	"net"
 	"net/http"
 	_ "net/http/pprof"
 	"os"
@@ -58,7 +57,7 @@ func dcrdMain(serverChan chan<- *server) error {
 	// Enable http profiling server if requested.
 	if cfg.Profile != "" {
 		go func() {
-			listenAddr := net.JoinHostPort("", cfg.Profile)
+			listenAddr := cfg.Profile
 			dcrdLog.Infof("Creating profiling server "+
 				"listening on %s", listenAddr)
 			profileRedirect := http.RedirectHandler("/debug/pprof",

doc.go

@@ -76,7 +76,7 @@ Application Options:
       --nocheckpoints       Disable built-in checkpoints.  Don't do this unless
                             you know what you're doing.
       --dbtype=             Database backend to use for the Block Chain (ffldb)
-      --profile=            Enable HTTP profiling on given port -- NOTE port
+      --profile=            Enable HTTP profiling on given [addr:]port -- NOTE: port
                             must be between 1024 and 65536
       --cpuprofile=         Write CPU profile to the specified file
       --memprofile=         Write mem profile to the specified file

sampleconfig/sampleconfig.go

@@ -333,8 +333,20 @@ const FileContents = `[Application Options]
 ; available subsystems.
 ; debuglevel=info
 
-; The port used to listen for HTTP profile requests.  The profile server will
-; be disabled if this option is not specified.  The profile information can be
-; accessed at http://localhost:<profileport>/debug/pprof once running.
-; profile=6061
+; ------------------------------------------------------------------------------
+; Profile - enable the HTTP profiler
+; ------------------------------------------------------------------------------
+
+; The profile server will be disabled if this option is not specified.  Profile
+; information can be accessed at http://ipaddr:<profileport>/debug/pprof once
+; running.  Note that the IP address will default to 127.0.0.1 if an IP address
+; is not specified, so that the profiler is not accessible on the network.
+; Listen on selected port on localhost only:
+;   profile=6061
+; Listen on selected port on all network interfaces:
+;   profile=:6061
+; Listen on single network ipv4 interface:
+;   profile=192.168.1.123:6061
+; Listen on ipv6 loopback interface:
+;   profile=[::1]:6061
 `