| // Copyright 2016 CoreOS, Inc. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| package daemon |
| |
| import ( |
| "fmt" |
| "os" |
| "strconv" |
| "time" |
| ) |
| |
| // SdWatchdogEnabled returns watchdog information for a service. |
| // Processes should call daemon.SdNotify(false, daemon.SdNotifyWatchdog) every |
| // time / 2. |
| // If `unsetEnvironment` is true, the environment variables `WATCHDOG_USEC` and |
| // `WATCHDOG_PID` will be unconditionally unset. |
| // |
| // It returns one of the following: |
| // (0, nil) - watchdog isn't enabled or we aren't the watched PID. |
| // (0, err) - an error happened (e.g. error converting time). |
| // (time, nil) - watchdog is enabled and we can send ping. |
| // time is delay before inactive service will be killed. |
| func SdWatchdogEnabled(unsetEnvironment bool) (time.Duration, error) { |
| wusec := os.Getenv("WATCHDOG_USEC") |
| wpid := os.Getenv("WATCHDOG_PID") |
| if unsetEnvironment { |
| wusecErr := os.Unsetenv("WATCHDOG_USEC") |
| wpidErr := os.Unsetenv("WATCHDOG_PID") |
| if wusecErr != nil { |
| return 0, wusecErr |
| } |
| if wpidErr != nil { |
| return 0, wpidErr |
| } |
| } |
| |
| if wusec == "" { |
| return 0, nil |
| } |
| s, err := strconv.Atoi(wusec) |
| if err != nil { |
| return 0, fmt.Errorf("error converting WATCHDOG_USEC: %s", err) |
| } |
| if s <= 0 { |
| return 0, fmt.Errorf("error WATCHDOG_USEC must be a positive number") |
| } |
| interval := time.Duration(s) * time.Microsecond |
| |
| if wpid == "" { |
| return interval, nil |
| } |
| p, err := strconv.Atoi(wpid) |
| if err != nil { |
| return 0, fmt.Errorf("error converting WATCHDOG_PID: %s", err) |
| } |
| if os.Getpid() != p { |
| return 0, nil |
| } |
| |
| return interval, nil |
| } |