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sevlyar / go-daemon

A library for writing system daemons in golang.
MIT License
2.18k stars 246 forks source link

null derefernce in daemon child process #56

Closed barp closed 5 years ago

barp commented 5 years ago

library crashes when it fails to parse json from stdin in the child process in function child in daemon_unix.go

    decoder := json.NewDecoder(os.Stdin)
    if err = decoder.Decode(d); err != nil {
        d.pidFile.Remove()
        return
    }

d.pidFile is not yet initialized at this point

it is initialized at lines below it

    // create PID file after context decoding to know PID file full path.
    if len(d.PidFileName) > 0 {
        d.pidFile = NewLockFile(os.NewFile(4, d.PidFileName))
        if err = d.pidFile.WritePid(); err != nil {
            return
        }
    }

this cause null deference

gopkg.in/sevlyar/go-daemon%2ev0.(LockFile).Remove(0x0, 0x0, 0x0) /go/pkg/mod/gopkg.in/sevlyar/go-daemon.v0@v0.1.4/lock_file.go:102 +0x2e gopkg.in/sevlyar/go-daemon%2ev0.(Context).child(0xc00007c410, 0x491dbd, 0x65ac7b) /go/pkg/mod/gopkg.in/sevlyar/go-daemon.v0@v0.1.4/daemon_unix.go:238 +0x1e0 gopkg.in/sevlyar/go-daemon%2ev0.(Context).reborn(0xc00007c410, 0x0, 0x1e, 0x1) /go/pkg/mod/gopkg.in/sevlyar/go-daemon.v0@v0.1.4/daemon_unix.go:61 +0x36 gopkg.in/sevlyar/go-daemon%2ev0.(Context).Reborn(0xc00007c410, 0x6, 0xc0000924a0, 0x1e)
/go/pkg/mod/gopkg.in/sevlyar/go-daemon.v0@v0.1.4/daemon.go:31 +0x2b