Fix IRC listener relay of bodies and modes, and JOIN names (closes #127)

The IRC listener relayed only the first line of a PRIVMSG or NOTICE
body; it now sends one line per body line. A relayed MODE change now
carries its key, limit or mask, each value its own parameter, also in
the echo to the user who made it. CR, LF and NUL are removed from each
parameter and from each whole line sent to an IRC listener connection,
so no stored value can start a line of its own. The channel name check
moved into service.JoinChannel, so the IRC listener's JOIN refuses the
same names with 403.

Model: opus-5-5

internal/handlers/api_test.go

@@ -7,6 +7,7 @@ package handlers_test
 import (
 	"bytes"
 	"context"
+	"crypto/rand"
 	"database/sql"
 	"encoding/json"
 	"errors"
@@ -152,9 +153,12 @@ func newTestServerWith(
 ) *testServer {
 	t.Helper()
 
+	// A random name, so that no other test can share it, not
+	// even one that has finished but still holds its database
+	// open.
 	dbURL := fmt.Sprintf(
-		"file:test_%p?mode=memory&cache=shared",
-		t,
+		"file:%s?mode=memory&cache=shared",
+		rand.Text(),
 	)
 	copyTemplateDB(t, dbURL)
 
@@ -667,6 +671,29 @@ func TestCreateSessionDuplicate(t *testing.T) {
 	}
 }
 
+// TestEachTestServerHasItsOwnDatabase checks that starting a
+// second test server leaves the first one's database alone and
+// starts on an empty one of its own.
+func TestEachTestServerHasItsOwnDatabase(t *testing.T) {
+	first := newTestServer(t)
+	first.createSession("samenick")
+
+	second := newTestServer(t)
+
+	resp := postSession(t, first, "samenick")
+
+	defer func() { _ = resp.Body.Close() }()
+
+	if resp.StatusCode != http.StatusConflict {
+		t.Fatalf(
+			"first server: expected 409, got %d",
+			resp.StatusCode,
+		)
+	}
+
+	second.createSession("samenick")
+}
+
 func TestCreateSessionEmpty(t *testing.T) {
 	tserver := newTestServer(t)
 

internal/ircserver/conn_test.go

@@ -5,6 +5,7 @@ import (
 	"log/slog"
 	"net"
 	"os"
+	"slices"
 	"strings"
 	"testing"
 	"time"
@@ -100,3 +101,48 @@ func TestDisconnectNotifiesAndClosesVictim(t *testing.T) {
 		t.Errorf("missing ERROR line, got: %q", joined)
 	}
 }
+
+// TestDisconnectReasonCannotStartLine checks that CR, LF and
+// NUL in a KILL reason are removed from both the KILL line
+// and the ERROR line, so the victim gets exactly those two
+// lines. The ERROR line is not built with FormatMessage, so
+// only the removal in sendWithin protects it.
+func TestDisconnectReasonCannotStartLine(t *testing.T) {
+	t.Parallel()
+
+	victim, clientSide := newKillVictim(t)
+	received := make(chan []string, 1)
+
+	go func() {
+		var lines []string
+
+		scanner := bufio.NewScanner(clientSide)
+		for scanner.Scan() {
+			lines = append(lines, scanner.Text())
+		}
+
+		received <- lines
+	}()
+
+	victim.Disconnect("bye\r\nPRIVMSG victim :forged\x00")
+
+	var lines []string
+
+	select {
+	case lines = <-received:
+	case <-time.After(testTimeout):
+		t.Fatal("the victim's connection was not closed")
+	}
+
+	// The test connection has no host name, hence the two
+	// spaces after "Closing Link:".
+	want := []string{
+		":" + testServerName +
+			" KILL victim :byePRIVMSG victim :forged",
+		"ERROR :Closing Link:  (byePRIVMSG victim :forged)",
+	}
+
+	if !slices.Equal(lines, want) {
+		t.Errorf("got lines %q, want %q", lines, want)
+	}
+}

internal/service/service_test.go

@@ -6,6 +6,7 @@ package service_test
 
 import (
 	"context"
+	"crypto/rand"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -43,9 +44,12 @@ type testEnv struct {
 func newTestEnv(t *testing.T) *testEnv {
 	t.Helper()
 
+	// A random name, so that no other test can share it, not
+	// even one that has finished but still holds its database
+	// open.
 	dbURL := fmt.Sprintf(
-		"file:svc_test_%p?mode=memory&cache=shared",
-		t,
+		"file:%s?mode=memory&cache=shared",
+		rand.Text(),
 	)
 
 	var (
@@ -137,6 +141,19 @@ func createSession(
 	return sessionID
 }
 
+// TestEachTestEnvHasItsOwnDatabase checks that a test
+// environment starts on an empty database while another one
+// is still open.
+func TestEachTestEnvHasItsOwnDatabase(t *testing.T) {
+	ctx := t.Context()
+
+	first := newTestEnv(t)
+	createSession(ctx, t, first.db, "samenick")
+
+	second := newTestEnv(t)
+	createSession(ctx, t, second.db, "samenick")
+}
+
 func TestFanOut(t *testing.T) {
 	env := newTestEnv(t)
 	ctx := t.Context()