minio/internal/logger/targets.go
Klaus Post d9c1d79e30
Protect logger targets (#13529)
Logger targets were not race protected against concurrent updates from for example `HTTPConsoleLoggerSys`.

Restrict direct access to targets and make slices immutable so a returned slice can be processed safely without locks.
2021-10-28 07:35:28 -07:00

107 lines
2.9 KiB
Go

// Copyright (c) 2015-2021 MinIO, Inc.
//
// This file is part of MinIO Object Storage stack
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package logger
import (
"sync"
"sync/atomic"
)
// Target is the entity that we will receive
// a single log entry and Send it to the log target
// e.g. Send the log to a http server
type Target interface {
String() string
Endpoint() string
Init() error
Send(entry interface{}, errKind string) error
}
// swapMu must be held while reading slice info or swapping targets or auditTargets.
var swapMu sync.Mutex
// targets is the set of enabled loggers.
// Must be immutable at all times.
// Can be swapped to another while holding swapMu
var targets = []Target{}
var nTargets int32 // atomic count of len(targets)
// Targets returns active targets.
// Returned slice may not be modified in any way.
func Targets() []Target {
if atomic.LoadInt32(&nTargets) == 0 {
// Lock free if none...
return nil
}
swapMu.Lock()
res := targets
swapMu.Unlock()
return res
}
// AuditTargets returns active audit targets.
// Returned slice may not be modified in any way.
func AuditTargets() []Target {
if atomic.LoadInt32(&nAuditTargets) == 0 {
// Lock free if none...
return nil
}
swapMu.Lock()
res := auditTargets
swapMu.Unlock()
return res
}
// auditTargets is the list of enabled audit loggers
// Must be immutable at all times.
// Can be swapped to another while holding swapMu
var auditTargets = []Target{}
var nAuditTargets int32 // atomic count of len(auditTargets)
// AddAuditTarget adds a new audit logger target to the
// list of enabled loggers
func AddAuditTarget(t Target) error {
if err := t.Init(); err != nil {
return err
}
swapMu.Lock()
updated := append(make([]Target, 0, len(auditTargets)+1), auditTargets...)
updated = append(updated, t)
auditTargets = updated
atomic.StoreInt32(&nAuditTargets, int32(len(updated)))
swapMu.Unlock()
return nil
}
// AddTarget adds a new logger target to the
// list of enabled loggers
func AddTarget(t Target) error {
if err := t.Init(); err != nil {
return err
}
swapMu.Lock()
updated := append(make([]Target, 0, len(targets)+1), targets...)
updated = append(updated, t)
targets = updated
atomic.StoreInt32(&nTargets, int32(len(updated)))
swapMu.Unlock()
return nil
}