Add the tier 3 utility IRC commands (closes #87)

USERHOST, VERSION, ADMIN, INFO, TIME, KILL and WALLOPS work on the
HTTP API and on the IRC listener. The USERHOST reply, the VERSION,
ADMIN and INFO text, KILL and WALLOPS are each one service function
that both transports call. User mode +w selects who receives WALLOPS.
MODE on your own nick queries or changes your user modes through one
parser on both transports: the whole mode string is checked before
anything is stored, and both flags are stored in one transaction. KILL
closes the victim's IRC connection after sending it KILL and ERROR,
without the operator waiting on it. The sessions table gains
is_wallops in 001_initial.sql, as the pre-1.0 rule in REPO_POLICIES.md
asks.

Model: opus-5-5
Co-authored-by: clawbot <sneak+clawbot@sneak.cloud>

internal/db/export_test.go

@@ -58,3 +58,17 @@ func (database *Database) Close() error {
 
 	return nil
 }
+
+// ExecForTest runs a raw statement, such as a trigger that
+// makes a write fail.
+func (database *Database) ExecForTest(
+	ctx context.Context,
+	query string,
+) error {
+	_, err := database.conn.ExecContext(ctx, query)
+	if err != nil {
+		return fmt.Errorf("exec for test: %w", err)
+	}
+
+	return nil
+}

internal/db/queries.go

@@ -7,6 +7,7 @@ import (
 	"database/sql"
 	"encoding/hex"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"strconv"
 	"strings"
@@ -2423,3 +2424,172 @@ func (database *Database) SetChannelUserLimit(
 
 	return nil
 }
+
+// SetSessionUserModes sets a session's wallops (+w) and
+// oper (+o) flags in one transaction, so that either both
+// changes are stored or neither is. A nil flag is left as
+// it is.
+func (database *Database) SetSessionUserModes(
+	ctx context.Context,
+	sessionID int64,
+	wallops *bool,
+	oper *bool,
+) error {
+	transaction, err := database.conn.BeginTx(ctx, nil)
+	if err != nil {
+		return fmt.Errorf("begin tx: %w", err)
+	}
+
+	if wallops != nil {
+		_, err = transaction.ExecContext(
+			ctx,
+			`UPDATE sessions SET is_wallops = ? WHERE id = ?`,
+			boolToInt(*wallops), sessionID,
+		)
+		if err != nil {
+			_ = transaction.Rollback()
+
+			return fmt.Errorf("set session wallops: %w", err)
+		}
+	}
+
+	if oper != nil {
+		_, err = transaction.ExecContext(
+			ctx,
+			`UPDATE sessions SET is_oper = ? WHERE id = ?`,
+			boolToInt(*oper), sessionID,
+		)
+		if err != nil {
+			_ = transaction.Rollback()
+
+			return fmt.Errorf("set session oper: %w", err)
+		}
+	}
+
+	err = transaction.Commit()
+	if err != nil {
+		return fmt.Errorf("commit user modes: %w", err)
+	}
+
+	return nil
+}
+
+// boolToInt returns the 0 or 1 that the schema stores for a
+// boolean.
+func boolToInt(value bool) int {
+	if value {
+		return 1
+	}
+
+	return 0
+}
+
+// IsSessionWallops returns whether the session has the
+// wallops (+w) usermode set.
+func (database *Database) IsSessionWallops(
+	ctx context.Context,
+	sessionID int64,
+) (bool, error) {
+	var isWallops int
+
+	err := database.conn.QueryRowContext(
+		ctx,
+		`SELECT is_wallops FROM sessions WHERE id = ?`,
+		sessionID,
+	).Scan(&isWallops)
+	if err != nil {
+		return false, fmt.Errorf(
+			"check session wallops: %w", err,
+		)
+	}
+
+	return isWallops != 0, nil
+}
+
+// GetWallopsSessionIDs returns all session IDs that have
+// the wallops (+w) usermode set.
+func (database *Database) GetWallopsSessionIDs(
+	ctx context.Context,
+) ([]int64, error) {
+	rows, err := database.conn.QueryContext(
+		ctx,
+		`SELECT id FROM sessions WHERE is_wallops = 1`,
+	)
+	if err != nil {
+		return nil, fmt.Errorf(
+			"get wallops sessions: %w", err,
+		)
+	}
+
+	defer func() { _ = rows.Close() }()
+
+	var ids []int64
+
+	for rows.Next() {
+		var sessionID int64
+
+		err = rows.Scan(&sessionID)
+		if err != nil {
+			return nil, fmt.Errorf(
+				"scan wallops session: %w", err,
+			)
+		}
+
+		ids = append(ids, sessionID)
+	}
+
+	err = rows.Err()
+	if err != nil {
+		return nil, fmt.Errorf(
+			"iterate wallops sessions: %w", err,
+		)
+	}
+
+	return ids, nil
+}
+
+// UserhostInfo holds the data needed for RPL_USERHOST.
+type UserhostInfo struct {
+	Nick        string
+	Username    string
+	Hostname    string
+	IsOper      bool
+	AwayMessage string
+}
+
+// GetUserhostInfo returns USERHOST info for the given
+// nicks. Nicks with no session are left out.
+func (database *Database) GetUserhostInfo(
+	ctx context.Context,
+	nicks []string,
+) ([]UserhostInfo, error) {
+	results := make([]UserhostInfo, 0, len(nicks))
+
+	for _, nick := range nicks {
+		var info UserhostInfo
+
+		err := database.conn.QueryRowContext(
+			ctx,
+			`SELECT nick, username, hostname,
+			        is_oper, away_message
+			 FROM sessions WHERE nick = ?`,
+			nick,
+		).Scan(
+			&info.Nick, &info.Username, &info.Hostname,
+			&info.IsOper, &info.AwayMessage,
+		)
+		if errors.Is(err, sql.ErrNoRows) {
+			continue
+		}
+
+		if err != nil {
+			return nil, fmt.Errorf(
+				"userhost lookup %q: %w", nick, err,
+			)
+		}
+
+		results = append(results, info)
+	}
+
+	return results, nil
+}

internal/db/queries_test.go

@@ -1491,3 +1491,119 @@ func TestChannelUserLimit(t *testing.T) {
 		t.Fatalf("expected 0, got %d", limit)
 	}
 }
+
+// TestSetSessionUserModesIsAtomic makes the is_oper write
+// fail after the is_wallops write has run, and checks that
+// the wallops change was rolled back.
+func TestSetSessionUserModesIsAtomic(t *testing.T) {
+	t.Parallel()
+
+	database := setupTestDB(t)
+	ctx := t.Context()
+
+	sessionID, _, _, err := database.CreateSession(
+		ctx, "alice", "", "", "",
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = database.ExecForTest(ctx,
+		`CREATE TRIGGER reject_oper
+		 BEFORE UPDATE OF is_oper ON sessions
+		 BEGIN SELECT RAISE(ABORT, 'oper write rejected');
+		 END`,
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	wallops := true
+	oper := false
+
+	err = database.SetSessionUserModes(
+		ctx, sessionID, &wallops, &oper,
+	)
+	if err == nil {
+		t.Fatal("expected the rejected oper write to fail")
+	}
+
+	gotWallops, err := database.IsSessionWallops(
+		ctx, sessionID,
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if gotWallops {
+		t.Error("wallops was stored although the change failed")
+	}
+}
+
+// TestSetSessionUserModesAppliesBoth checks that both flags
+// are written, and that a nil flag is left as it is.
+func TestSetSessionUserModesAppliesBoth(t *testing.T) {
+	t.Parallel()
+
+	database := setupTestDB(t)
+	ctx := t.Context()
+
+	sessionID, _, _, err := database.CreateSession(
+		ctx, "alice", "", "", "",
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = database.SetSessionOper(ctx, sessionID, true)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	wallops := true
+	oper := false
+
+	err = database.SetSessionUserModes(
+		ctx, sessionID, &wallops, &oper,
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	gotWallops, err := database.IsSessionWallops(
+		ctx, sessionID,
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	gotOper, err := database.IsSessionOper(ctx, sessionID)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !gotWallops || gotOper {
+		t.Errorf(
+			"want wallops=true oper=false, got %v/%v",
+			gotWallops, gotOper,
+		)
+	}
+
+	err = database.SetSessionUserModes(
+		ctx, sessionID, nil, nil,
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	gotWallops, err = database.IsSessionWallops(
+		ctx, sessionID,
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !gotWallops {
+		t.Error("a nil wallops flag cleared wallops")
+	}
+}

internal/db/schema/001_initial.sql

@@ -10,6 +10,7 @@ CREATE TABLE IF NOT EXISTS sessions (
     hostname TEXT NOT NULL DEFAULT '',
     ip TEXT NOT NULL DEFAULT '',
     is_oper INTEGER NOT NULL DEFAULT 0,
+    is_wallops INTEGER NOT NULL DEFAULT 0,
     password_hash TEXT NOT NULL DEFAULT '',
     signing_key TEXT NOT NULL DEFAULT '',
     away_message TEXT NOT NULL DEFAULT '',