Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC r229699, r229744, r229778, r229944, r229945, r229946, r230092, r230395,
r230396, r230436, r230457, r230515, r230976:

r229744 (pjd):

fork(2) returns -1 on failure, not some random negative number.

r229699 (pjd):

Constify argument.

r229778 (uqs):

Spelling fixes for sbin/

r229944 (pjd):

Don't touch pidfiles when running in foreground. Before that change we
would create an empty pidfile on start and check if it changed on SIGHUP.

r229945 (pjd):

For functions that return -1 on failure check exactly for -1 and not for
any negative number.

r229946 (pjd):

- Fix a bug where pidfile was removed in SIGHUP when it hasn't changed in
configuration file.
- Log the fact that pidfile has changed.

r230092 (pjd):

Style cleanups.

r230395 (pjd):

Remove unused token 'port'.

r230396 (pjd):

Remove another unused token.

r230436 (pjd):

Fix minor memory leak.

r230457 (pjd):

Free memory that won't be used in child.

r230515 (pjd):

- Fix documentation to note that /etc/hast.conf is the default configuration
file for hastd(8) and hastctl(8) and not hast.conf.
- In copyright statement correct that this file is documentation, not software.
- Bump date.

r230976 (pjd):

Fix typo in comment.

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

The proto API is a general purpose API, so don't use 'hast' in structures or
function names. It can now be used outside of HAST.

MFC after: 1 week

In hast.conf we define the other node's address in 'remote' variable.
This way we know how to connect to secondary node when we are primary.
The same variable is used by the secondary node - it only accepts
connections from the address stored in 'remote' variable.
In cluster configurations it is common that each node has its individual
IP address and there is one addtional shared IP address which is assigned
to primary node. It seems it is possible that if the shared IP address is
from the same network as the individual IP address it might be choosen by
the kernel as a source address for connection with the secondary node.
Such connection will be rejected by secondary, as it doesn't come from
primary node individual IP.

Add 'source' variable that allows to specify source IP address we want to
bind to before connecting to the secondary node.

MFC after: 1 week

When we decide to unlink socket file, sun_path must be set. If it is set,
but there is problem unlinking the file, log a warning.

MFC after: 1 week

Explicitly include <sys/types.h> as suggested by getpid(2) and don't rely on
<sys/un.h> including what's needed.

MFC after: 1 week

Unlink UNIX domain socket file only if:
1. The descriptor is the one we are listening on (not the one when we connect
as a client and not the one which is created on accept(2)).
2. Descriptor was created by us (PID matches with the PID stored on bind(2)).

Reported by: Mikolaj Golub <to.my.trociny@gmail.com>
MFC after: 1 week

- Rename proto_descriptor_{send,recv}() functions to
proto_connection_{send,recv} and change them to return proto_conn
structure. We don't operate directly on descriptors, but on
proto_conns.
- Add wrap method to wrap descriptor with proto_conn.
- Remove methods to send and receive descriptors and implement this
functionality as additional argument to send and receive methods.

MFC after: 1 week

Add proto_connect_wait() to wait for connection to finish.
If timeout argument to proto_connect() is -1, then the caller needs to use
this new function to wait for connection.

This change is in preparation for capsicum, where sandboxed worker wants
to ask main process to connect in worker's behalf and pass descriptor
to the worker. Because we don't want the main process to wait for the
connection, it will start async connection and pass descriptor to the
worker who will be responsible for waiting for the connection to finish.

MFC after: 1 week

Allow to specify connection timeout by the caller.

MFC after: 1 week

Implement two new functions for sending descriptor and receving descriptor
over UNIX domain sockets and socket pairs.
This is in preparation for capsicum.

MFC after: 1 week

- Use pjdlog for assertions and aborts as this will log assert/abort message
to syslog if we run in background.
- Asserts in proto.c that method we want to call is implemented and remove
dummy methods from protocols implementation that are only there to abort
the program with nice message.

MFC after: 1 week

Assert that various buffers we are large enough.

MFC after: 1 month

Add an argument to the proto_register() function which allows protocol to
declare it is the default and be placed at the end of the queue so it is
checked last.

MFC after: 1 month

Please welcome HAST - Highly Avalable Storage.

HAST allows to transparently store data on two physically separated machines
connected over the TCP/IP network. HAST works in Primary-Secondary
(Master-Backup, Master-Slave) configuration, which means that only one of the
cluster nodes can be active at any given time. Only Primary node is able to
handle I/O requests to HAST-managed devices. Currently HAST is limited to two
cluster nodes in total.

HAST operates on block level - it provides disk-like devices in /dev/hast/
directory for use by file systems and/or applications. Working on block level
makes it transparent for file systems and applications. There in no difference
between using HAST-provided device and raw disk, partition, etc. All of them
are just regular GEOM providers in FreeBSD.

For more information please consult hastd(8), hastctl(8) and hast.conf(5)
manual pages, as well as http://wiki.FreeBSD.org/HAST.

Sponsored by: FreeBSD Foundation
Sponsored by: OMCnet Internet Service GmbH
Sponsored by: TransIP BV