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89 lines
2.7 KiB
Go
89 lines
2.7 KiB
Go
package daemon
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import (
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"errors"
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"os"
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"syscall"
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)
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var errNotSupported = errors.New("daemon: Non-POSIX OS is not supported")
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// Mark of daemon process - system environment variable _GO_DAEMON=1
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const (
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MARK_NAME = "_GO_DAEMON"
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MARK_VALUE = "1"
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)
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// Default file permissions for log and pid files.
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const FILE_PERM = os.FileMode(0640)
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// A Context describes daemon context.
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type Context struct {
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// If PidFileName is non-empty, parent process will try to create and lock
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// pid file with given name. Child process writes process id to file.
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PidFileName string
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// Permissions for new pid file.
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PidFilePerm os.FileMode
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// If LogFileName is non-empty, parent process will create file with given name
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// and will link to fd 2 (stderr) for child process.
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LogFileName string
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// Permissions for new log file.
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LogFilePerm os.FileMode
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// If WorkDir is non-empty, the child changes into the directory before
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// creating the process.
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WorkDir string
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// If Chroot is non-empty, the child changes root directory
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Chroot string
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// If Env is non-nil, it gives the environment variables for the
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// daemon-process in the form returned by os.Environ.
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// If it is nil, the result of os.Environ will be used.
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Env []string
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// If Args is non-nil, it gives the command-line args for the
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// daemon-process. If it is nil, the result of os.Args will be used
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// (without program name).
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Args []string
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// Credential holds user and group identities to be assumed by a daemon-process.
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Credential *syscall.Credential
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// If Umask is non-zero, the daemon-process call Umask() func with given value.
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Umask int
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// Struct contains only serializable public fields (!!!)
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abspath string
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pidFile *LockFile
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logFile *os.File
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nullFile *os.File
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rpipe, wpipe *os.File
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}
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// WasReborn returns true in child process (daemon) and false in parent process.
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func WasReborn() bool {
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return os.Getenv(MARK_NAME) == MARK_VALUE
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}
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// Reborn runs second copy of current process in the given context.
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// function executes separate parts of code in child process and parent process
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// and provides demonization of child process. It look similar as the
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// fork-daemonization, but goroutine-safe.
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// In success returns *os.Process in parent process and nil in child process.
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// Otherwise returns error.
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func (d *Context) Reborn() (child *os.Process, err error) {
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return d.reborn()
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}
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// Search search daemons process by given in context pid file name.
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// If success returns pointer on daemons os.Process structure,
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// else returns error. Returns nil if filename is empty.
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func (d *Context) Search() (daemon *os.Process, err error) {
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return d.search()
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}
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// Release provides correct pid-file release in daemon.
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func (d *Context) Release() (err error) {
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return d.release()
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}
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