Struct Image 

pub struct Image { /* private fields */ }

What a long-lived process’s image was started from (now, at its start): whether it is the binary installed now.

Implementations

impl Image

pub fn now() -> Image

pub fn stale(&self) -> bool

The path names another file than at the start (or none), or the running binary was deleted: this image is old code.

pub fn due(&self) -> bool

Stale, and the path holds an executable no exec failed on: a re-exec is worth trying.

pub fn reexec( &mut self, lock: &File, stopped: impl Fn() -> bool, ) -> Result<(), ReexecError>

For a waiter (listen.rs): replaces this process’s image by the file at its path, same pid, argv and environment, stdout and stderr flushed, the stop signals blocked across (stopped looked at once more after they are), lock’s open file description passed on as a duplicate without close-on-exec (ADOPT_FD). Returns only when it did not happen: Ok when a stop came (the caller ends as stopped), Err with why the exec failed (the path is not tried again until it changes).

Errors

The dup or the exec failed (ReexecError).

pub fn restart(&mut self) -> Result<(), String>

For the mesh daemon, once it stopped serving: replaces its image by the file at its path, stdout and stderr flushed, same pid, argv and environment, with SIGINT, SIGHUP and SIGTERM blocked across; a stop trap_stops saw first returns Ok (the caller ends as stopped), one that comes later stays pending for the new image (trap_stops there). Only a file whose probe says it unblocks them there (takes_restart) is exec’d. On Linux it first waits up to ALONE_WAIT for its other threads to end, so none can take a stop meanwhile (the daemon’s are gone once its runtime shut down). Err with what the engineer does now.