khenaidoo | ffe076b | 2019-01-15 16:08:08 -0500 | [diff] [blame^] | 1 | // Copyright 2016 CoreOS, Inc. |
| 2 | // |
| 3 | // Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | // you may not use this file except in compliance with the License. |
| 5 | // You may obtain a copy of the License at |
| 6 | // |
| 7 | // http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | // |
| 9 | // Unless required by applicable law or agreed to in writing, software |
| 10 | // distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | // See the License for the specific language governing permissions and |
| 13 | // limitations under the License. |
| 14 | |
| 15 | package daemon |
| 16 | |
| 17 | import ( |
| 18 | "fmt" |
| 19 | "os" |
| 20 | "strconv" |
| 21 | "time" |
| 22 | ) |
| 23 | |
| 24 | // SdWatchdogEnabled returns watchdog information for a service. |
| 25 | // Processes should call daemon.SdNotify(false, daemon.SdNotifyWatchdog) every |
| 26 | // time / 2. |
| 27 | // If `unsetEnvironment` is true, the environment variables `WATCHDOG_USEC` and |
| 28 | // `WATCHDOG_PID` will be unconditionally unset. |
| 29 | // |
| 30 | // It returns one of the following: |
| 31 | // (0, nil) - watchdog isn't enabled or we aren't the watched PID. |
| 32 | // (0, err) - an error happened (e.g. error converting time). |
| 33 | // (time, nil) - watchdog is enabled and we can send ping. |
| 34 | // time is delay before inactive service will be killed. |
| 35 | func SdWatchdogEnabled(unsetEnvironment bool) (time.Duration, error) { |
| 36 | wusec := os.Getenv("WATCHDOG_USEC") |
| 37 | wpid := os.Getenv("WATCHDOG_PID") |
| 38 | if unsetEnvironment { |
| 39 | wusecErr := os.Unsetenv("WATCHDOG_USEC") |
| 40 | wpidErr := os.Unsetenv("WATCHDOG_PID") |
| 41 | if wusecErr != nil { |
| 42 | return 0, wusecErr |
| 43 | } |
| 44 | if wpidErr != nil { |
| 45 | return 0, wpidErr |
| 46 | } |
| 47 | } |
| 48 | |
| 49 | if wusec == "" { |
| 50 | return 0, nil |
| 51 | } |
| 52 | s, err := strconv.Atoi(wusec) |
| 53 | if err != nil { |
| 54 | return 0, fmt.Errorf("error converting WATCHDOG_USEC: %s", err) |
| 55 | } |
| 56 | if s <= 0 { |
| 57 | return 0, fmt.Errorf("error WATCHDOG_USEC must be a positive number") |
| 58 | } |
| 59 | interval := time.Duration(s) * time.Microsecond |
| 60 | |
| 61 | if wpid == "" { |
| 62 | return interval, nil |
| 63 | } |
| 64 | p, err := strconv.Atoi(wpid) |
| 65 | if err != nil { |
| 66 | return 0, fmt.Errorf("error converting WATCHDOG_PID: %s", err) |
| 67 | } |
| 68 | if os.Getpid() != p { |
| 69 | return 0, nil |
| 70 | } |
| 71 | |
| 72 | return interval, nil |
| 73 | } |