The process abstraction has changed to:
setup(task, process)
start(task, process_data)
prefork(task, process, mp)
The prefork() occurs in the main process right before fork.
The file src/nxt_main_process.c is completely free of process
specific logic.
The creation of a process now supports a PROCESS_CREATED state. The
The setup() function of each process can set its state to either
created or ready. If created, a MSG_PROCESS_CREATED is sent to main
process, where external setup can be done (required for rootfs under
container).
The core processes (discovery, controller and router) doesn't need
external setup, then they all proceeds to their start() function
straight away.
In the case of applications, the load of the module happens at the
process setup() time and The module's init() function has changed
to be the start() of the process.
The module API has changed to:
setup(task, process, conf)
start(task, data)
As a direct benefit of the PROCESS_CREATED message, the clone(2) of
processes using pid namespaces now doesn't need to create a pipe
to make the child block until parent setup uid/gid mappings nor it
needs to receive the child pid.
After a process exits, all ports linked to it from other processes
should be closed. All unsent file descriptors in port queue, marked as
"close after send", should be closed to avoid resource leakage.
According to the C standard, pointer arguments passed to memcpy() calls shall
still have valid values. NULL is considered as invalid.
Found with GCC Static Analyzer.
This is useful to escape "/" in path fragments. For example, in order
to reference the application named "foo/bar":
{
"pass": "applications/foo%2Fbar"
}
This is required due to lack of a graceful shutdown: there is a small gap
between the runtime's memory pool release and router process's exit. Thus, a
worker thread may start processing a request between these two operations,
which may result in an http fields hash access and subsequent crash.
To simplify issue reproduction, it makes sense to add a 2 sec sleep before
exit() in nxt_runtime_exit().
After 41331471eee7 completion handlers should complete next buffer in chain.
Otherwise buffer memory may leak.
Thanks to Peter Tkatchenko for reporing the issue and testing fixes.
An earlier attempt (ad6265786871) to resolve this condition on the
router's side added a new issue: the app could get a request before
acquiring a port.
One of the ways to detect Unit's startup and subsequent readiness to accept
commands relies on waiting for the control socket file to be created.
Earlier, it was unreliable due to a race condition between the client's
connect() and the daemon's listen() calls after the socket's bind() call.
Now, unix domain listening sockets are created with a nxt_listen_socket_create()
call as follows:
s = socket();
unlink("path/to/socket.tmp")
bind(s, "path/to/socket.tmp");
listen(s);
rename("path/to/socket.tmp", "path/to/socket");
This eliminates a time-lapse when the socket file is already created but nobody
is listening on it yet, which therefore prevents the condition described above.
Also, it allows reliably detecting whether the socket is being used or simply
wasn't cleaned after the daemon stopped abruptly. A successful connection to
the socket file means the daemon has been started; otherwise, the file can be
overwritten.
