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|
package main
import (
"bufio"
"fmt"
"log"
"net"
"os"
"strconv"
)
var (
gConnList = make(map[int]net.Conn)
gQuitChan = make(chan struct{}, 1)
gListener net.Listener
)
func serve() {
if gLogPath != "" {
f, err := os.OpenFile(gLogPath, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0o600)
if err != nil {
log.Fatalf("failed to open log file: %s", err)
}
defer f.Close()
log.SetOutput(f)
}
log.Print("hi!")
if gSocketProt == "unix" {
setUserUmask()
}
l, err := net.Listen(gSocketProt, gSocketPath)
if err != nil {
log.Printf("listening socket: %s", err)
return
}
defer l.Close()
gListener = l
listen(l)
}
func listen(l net.Listener) {
for {
c, err := l.Accept()
if err != nil {
select {
case <-gQuitChan:
log.Printf("bye!")
return
default:
log.Printf("accepting connection: %s", err)
}
}
go handleConn(c)
}
}
func echoerr(c net.Conn, msg string) {
fmt.Fprintln(c, msg)
log.Print(msg)
}
func echoerrf(c net.Conn, format string, a ...any) {
echoerr(c, fmt.Sprintf(format, a...))
}
func handleConn(c net.Conn) {
s := bufio.NewScanner(c)
Loop:
for s.Scan() {
log.Printf("listen: %s", s.Text())
word, rest := splitWord(s.Text())
switch word {
case "conn":
if rest != "" {
word2, _ := splitWord(rest)
id, err := strconv.Atoi(word2)
if err != nil {
echoerr(c, "listen: conn: client id should be a number")
} else {
// lifetime of the connection is managed by the server and
// will be cleaned up via the `drop` command
gConnList[id] = c
return
}
} else {
echoerr(c, "listen: conn: requires a client id")
}
case "drop":
if rest != "" {
word2, _ := splitWord(rest)
id, err := strconv.Atoi(word2)
if err != nil {
echoerr(c, "listen: drop: client id should be a number")
} else {
if c2, ok := gConnList[id]; ok {
c2.Close()
}
delete(gConnList, id)
}
} else {
echoerr(c, "listen: drop: requires a client id")
}
case "send":
if rest != "" {
word2, rest2 := splitWord(rest)
id, err := strconv.Atoi(word2)
if err != nil {
for _, c := range gConnList {
fmt.Fprintln(c, rest)
}
} else {
if c2, ok := gConnList[id]; ok {
fmt.Fprintln(c2, rest2)
} else {
echoerr(c, "listen: send: no such client id is connected")
}
}
}
case "query":
if rest == "" {
echoerr(c, "listen: query: requires a client id")
break
}
word2, rest2 := splitWord(rest)
id, err := strconv.Atoi(word2)
if err != nil {
echoerr(c, "listen: query: client id should be a number")
break
}
c2, ok := gConnList[id]
if !ok {
echoerr(c, "listen: query: no such client id is connected")
break
}
fmt.Fprintln(c2, "query "+rest2)
s2 := bufio.NewScanner(c2)
for s2.Scan() && s2.Text() != "" {
fmt.Fprintln(c, s2.Text())
}
case "quit":
if len(gConnList) == 0 {
gQuitChan <- struct{}{}
gListener.Close()
break Loop
}
case "quit!":
gQuitChan <- struct{}{}
for _, c := range gConnList {
fmt.Fprintln(c, "echo server is quitting...")
c.Close()
}
gListener.Close()
break Loop
default:
echoerrf(c, "listen: unexpected command: %s", word)
}
}
if s.Err() != nil {
echoerrf(c, "listening: %s", s.Err())
}
c.Close()
}
|
