MFC r213183,r213428,r213429,r213430,r213529,r213530,r213531,r213533,r213579,

MFC r213183,r213428,r213429,r213430,r213529,r213530,r213531,r213533,r213579,
  r213580,r213938,r213939,r213981:

r213183:

Plug memory leak on fork(2) failure.

Submitted by:	Mikolaj Golub <to.my.trociny@gmail.com>

r213428:

We can't mask ignored signal, so install dummy signal hander for SIGCHLD before
masking it.

This fixes bogus reports about hooks running for too long and other problems
related to garbage-collecting child processes.

Reported by:	Mikolaj Golub <to.my.trociny@gmail.com>

r213429:

hook_check() is now only used to report about long-running hooks, so the
argument is redundant, remove it.

r213430:

Decrease report interval to 5 seconds, as this also means we will check for
signals every 5 seconds and not every 10 seconds as before.

r213529:

Don't close local component on exit as we can hang waiting on g_waitidle.
I'm unable to reproduce the race described in comment anymore and also the
comment is incorrect - localfd represents local component from configuration
file, eg. /dev/da0 and not HAST provider.

Reported by:	Mikolaj Golub <to.my.trociny@gmail.com>

r213530:

Start the guard thread first, so we can handle signals from the very begining.

Reported by:	Mikolaj Golub <to.my.trociny@gmail.com>

r213531:

Log error message when we fail to destroy ggate provider.

r213533:

Clear ggate structures before using them. We don't initialize all the field
and there can be some garbage from the stack.

r213579:

We close the event socketpair early in the mainloop to prevent spaming with
error messages, so when we clean up after child process, we have to check if
the event socketpair is still there.

Submitted by:	Mikolaj Golub <to.my.trociny@gmail.com>

r213580:

We can't zero out ggio request, as we have some fields in there we initialize
once during start-up.

Reported by:	Mikolaj Golub <to.my.trociny@gmail.com>

r213938:

Clear signal mask before executing a hook.

Submitted by:	Mikolaj Golub <to.my.trociny@gmail.com>

r213939:

Use one fprintf() instead of two.

r213981:

Log correct connection when canceling half-open connection.

Submitted by:	Mikolaj Golub <to.my.trociny@gmail.com>

git-svn-id: svn://svn.freebsd.org/base/stable/8@213984 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f