BUILD: checks: external checker needs signal.h

check.c doesn't build on solaris since 98637e5 ("MEDIUM: Add external check")
because sigset_t is unknown. Simply include signal.h to fix the issue.

No need to backport, this is 1.6-only.
BUILD: checks: kill a minor warning on Solaris in external checks

Gcc on Solaris complains that elem->pid is pid_t and that we display
it as int. A simple cast fixes this. No backport needed, this is 1.6
only.
BUILD: http: fix isdigit & isspace warnings on Solaris

As usual, when touching any is* function, Solaris complains about the
type of the element being checked. Better backport this to 1.5 since
nobody knows what the emitted code looks like since macros are used
instead of functions.
BUG/MINOR: listener: set the listener's fd to -1 after deletion

This is currently harmless, but when stopping a listener, its fd is
closed but not set to -1, so it is not possible to re-open it again.
Currently this has no impact but can have after the abstract sockets
are modified to perform a complete close on soft-reload.

The fix can be backported to 1.5 and may even apply to 1.4 (protocols.c).
BUG/MEDIUM: unix: failed abstract socket binding is retryable

Jan Seda noticed that abstract sockets are incompatible with soft reload,
because the new process cannot bind and immediately fails. This patch marks
the binding as retryable and not fatal so that the new process can try to
bind again after sending a signal to the old process.

Note that this fix is not enough to completely solve the problem, but it
is necessary. This patch should be backported to 1.5.
MEDIUM: listener: implement a per-protocol pause() function

In order to fix the abstact socket pause mechanism during soft restarts,
we'll need to proceed differently depending on the socket protocol. The
pause_listener() function already supports some protocol-specific handling
for the TCP case.

This commit makes this cleaner by adding a new ->pause() function to the
protocol struct, which, if defined, may be used to pause a listener of a
given protocol.

For now, only TCP has been adapted, with the specific code moved from
pause_listener() to tcp_pause_listener().
MEDIUM: listener: support rebinding during resume()

When a listener resumes operations, supporting a full rebind makes it
possible to perform a full stop as a pause(). This will be used for
pausing abstract namespace unix sockets.
BUG/MEDIUM: unix: completely unbind abstract sockets during a pause()

Abstract namespace sockets ignore the shutdown() call and do not make
it possible to temporarily stop listening. The issue it causes is that
during a soft reload, the new process cannot bind, complaining that the
address is already in use.

This change registers a new pause() function for unix sockets and
completely unbinds the abstract ones since it's possible to rebind
them later. It requires the two previous patches as well as preceeding
fixes.

This fix should be backported into 1.5 since the issue apperas there.
DOC: explicitly mention the limits of abstract namespace sockets

Listening to an abstract namespace socket is quite convenient but
comes with some drawbacks that must be clearly understood when the
socket is being listened to by multiple processes. The trouble is
that the socket cannot be rebound if a new process attempts a soft
restart and fails, so only one of the initially bound processes
will still be bound to it, the other ones will fail to rebind. For
most situations it's not an issue but it needs to be indicated.
DOC: expand the docs for the provided stats.

Indicate for each statistic which types may have a value for
that statistic.

Explain some of the provided statistics a little more deeply.
BUG/MEDIUM: backend: Update hash to use unsigned int throughout

When we were generating a hash, it was done using an unsigned long.  When the hash was used
to select a backend, it was sent as an unsigned int.  This made it difficult to predict which
backend would be selected.

This patch updates get_hash, and the hash methods to use an unsigned int, to remain consistent
throughout the codebase.

This fix should be backported to 1.5 and probably in part to 1.4.
DOC: minor fix on {sc,src}_kbytes_{in,out}

These ones report total amount of bytes, not byte rates.
This fix should be backported into 1.5 which has the same error.
DOC: fix alphabetical sort of converters

For an unknown reason, these ones were not sorted.
MEDIUM: stick-table: implement lookup from a sample fetch

Currently we have stktable_fetch_key() which fetches a sample according
to an expression and returns a stick table key, but we also need a function
which does only the second half of it from a known sample. So let's cut the
function in two and introduce smp_to_stkey() to perform this lookup. The
first function was adapted to make use of it in order to avoid code
duplication.
MEDIUM: stick-table: add new converters to fetch table data

These new converters make it possible to look up any sample expression
in a table, and check whether an equivalent key exists or not, and if it
exists, to retrieve the associated data (eg: gpc0, request rate, etc...).

Till now it was only possible using tracking, but sometimes tracking is
not suited to only retrieving such counters, either because it's done too
early or because too many items need to be checked without necessarily
being tracked.

These converters all take a string on input, and then convert it again to
the table's type. This means that if an input sample is of type IPv4 and
the table is of type IP, it will first be converted to a string, then back
to an IP address. This is a limitation of the current design which does not
allow converters to declare that "any" type is supported on input. Since
strings are the only types which can be cast to any other one, this method
always works.

The following converters were added :

  in_table, table_bytes_in_rate, table_bytes_out_rate, table_conn_cnt,
  table_conn_cur, table_conn_rate, table_gpc0, table_gpc0_rate,
  table_http_err_cnt, table_http_err_rate, table_http_req_cnt,
  table_http_req_rate, table_kbytes_in, table_kbytes_out,
  table_server_id, table_sess_cnt, table_sess_rate, table_trackers.
MINOR: samples: add two converters for the date format

This patch adds two converters :

   ltime(<format>[,<offset>])
   utime(<format>[,<offset>])

Both use strftime() to emit the output string from an input date. ltime()
provides local time, while utime() provides the UTC time.
BUG/MAJOR: http: correctly rewind the request body after start of forwarding

Daniel Dubovik reported an interesting bug showing that the request body
processing was still not 100% fixed. If a POST request contained short
enough data to be forwarded at once before trying to establish the
connection to the server, we had no way to correctly rewind the body.

The first visible case is that balancing on a header does not always work
on such POST requests since the header cannot be found. But there are even
nastier implications which are that http-send-name-header would apply to
the wrong location and possibly even affect part of the request's body
due to an incorrect rewinding.

There are two options to fix the problem :
  - first one is to force the HTTP_MSG_F_WAIT_CONN flag on all hash-based
    balancing algorithms and http-send-name-header, but there's always a
    risk that any new algorithm forgets to set it ;

  - the second option is to account for the amount of skipped data before
    the connection establishes so that we always know the position of the
    request's body relative to the buffer's origin.

The second option is much more reliable and fits very well in the spirit
of the past changes to fix forwarding. Indeed, at the moment we have
msg->sov which points to the start of the body before headers are forwarded
and which equals zero afterwards (so it still points to the start of the
body before forwarding data). A minor change consists in always making it
point to the start of the body even after data have been forwarded. It means
that it can get a negative value (so we need to change its type to signed)..

In order to avoid wrapping, we only do this as long as the other side of
the buffer is not connected yet.

Doing this definitely fixes the issues above for the requests. Since the
response cannot be rewound we don't need to perform any change there.

This bug was introduced/remained unfixed in 1.5-dev23 so the fix must be
backported to 1.5.
DOC: remove references to CPU=native in the README

Certain compilers running in virtualized environments may produce code
that the same processor cannot execute with -march=native, either because
of hypervisor bugs reporting wrong CPU features, or because of compiler
bugs forgetting to check CPU features. So better stop recommending this
combination so that users don't get trapped anymore.
DOC: mention that "compression offload" is ignored in defaults section

This one is not inherited from defaults into frontends nor backends
because it would create a confusion situation where it would be hard
to disable it (since both frontend and backend would enable it).
DOC: mention that Squid correctly responds 400 to PPv2 header

Amos reported that Squid builds 3.5.0.0_20140624 and 3.5.0.0_20140630
were confirmed to respond correctly here and that any version will do
the same.