Using the tmp sock_arg for storage, we can test all values with the same
logic and only differentiate hard-coded options from parameterized ones.

Stylistic polish by @mbgrydeland.

They can be stored directly in the sock_opts array or on the stack.

The sess and listen_sock structs contain everything we need to find or
infer the former `sock`, `uds` and `force` arguments. In particular, it
helps distinguish between working on a connection vs listen socket.

And conversely rename `to` variables to `so` for consistency.

Better diff with the --word-diff --word-diff-regex='\w+' options.

It is a 1:1 mapping with IPPROTO_TCP, so TCP_NODELAY was moved down to
be with the other IPPROTO_TCP options.

varnish core code should continue to use the VRE_* options, vmods
may now pass PCRE2_* options.

Make a note in the documentation of CLI Command File that it is necessary
to include an explicit 'vcl.use' command in the script.

Limit the selection of the active VCL from MGT's view point to be the last
startup VCL given. That would be the VCL from the very last -f argument
given to varnishd, or the autogenerated VCL from the -b argument (-f and
-b are mutually exclusive). Because all startup VCLs are always set to
state AUTO, and AUTO VCLs are made warm when the child is not
running (which it is not at the time the startup VCLs are compiled), this
ensures that it is a warm VCL that is selected as the active VCL.

With this patch, VCLs loaded through the use of an initial CLI command
script (-I option) will not cause a VCL to automatically be selected as
the active VCL. Rather, it is expected that the initial CLI command script
should have an explicit 'vcl.use' statement to select the active VCL. When
an active VCL is not set, attempts to start the child will fail, which
again will fail the varnishd daemon startup (unless -d is given) with an
error code.

The behaviour prior to this patch when using -I, -f '' (empty field), -F
or -d was not well defined. The first VCL loaded (either by -I startup CLI
script or a CLI 'vcl.load' command) would become the active VCL, even if
that VCL is loaded cold. That is an illegal state and would lead to
asserts. It is also not very useful functionality, given the typical use
case for -I is to set up VCL labels. Those require the tips of the VCL
tree dependency graph to be loaded first, and then the VCLs that selects
the label. This means that the active VCL will typically be the last VCL
loaded, which then will require the use of a 'vcl.use' statement in the -I
script anyways. This makes it an acceptable change of default behaviour
that should not affect users.

mgt_new_vcl() now returns a pointer to the newly compiled VCL program, or
NULL on failure.

This also fixes a wrong return value used previously which would cause a
"VCL compiled.\n" to be output to CLI when the child is not running even
when the VCL compilation step failed.

mgt_has_vcl() now returns an error string describing why it doesn't have a
valid VCL.

This is taken from #3711 by @bsdphk

It is very easy to confuse the child process' vcl_active and the
management process' active_vcl variables.

Rename mgt's active_vcl to mgt_vcl_active, following the naming scheme
used elsewhere.

Add a ASSERT_VCL_ACTIVE() macro that asserts that vcl_active either is
NULL or points to a VCL that is warm.

Sprinkle this macro in the various calls throughout the child process that
are involved in VCL handling.

Patch by: @alveelde

Do not select the first VCL present as the active VCL in the child
process. Instead it should always use what the mgt process tells it
through the explicit 'vcl.use' commands it will send.

Previously, the child could select a cold VCL as the active VCL if that
happened to be the first one present to it during restarts. This could
lead to asserts as that is not an allowed state.

One can still use the --without-unwind configure flag.

Refs #3717

For the purpose of simulating a workload where the cache process takes
significant time to shut down.

Using the wrong list variable would cause the dependency check to consider
VCLs that were not attempted discarded.

Fixes: #3734

As agreed with phk

bitshift of signed

avoid warning 666 ("Expression with side effects passed to repeated
parameter"): The non-type macros still trigger an warning due to the
expression passed a second time in typeof(). Use the typed macros for
these cases.

avoid error 1058 ("Initializing a non-const reference"): Our type
check (void)(&_va == &_vb) trips for dereferences.

Reviewing flexelint output for the recently added vmin/vmax macros
made apparent that vmin_t/vmax_t basically used typeof((cast)var),
which makes for an unnecessary de-tour via typeof.

We change the min/max macros to explicitly pass the type for the
temporary variables such that typeof() is only needed for vmin/vmax.

Being at it, we also reduce the min/max case to just one take macro
("take the min/max of ...") as they only differed in a single
character, the operator.

Fixes: left operand must be modifiable lvalue: op "="

Fixes warning on 32 bit:

comparison of distinct pointer types ('typeof ((*lp)) *' (aka 'int *') and
'typeof (((VRND_RandomTestable() & 3) + 1)) *' (aka 'long *'))

Minor rewrite for clarity.

VSL lines are truncated, so the return value _is_ sufficiently checked.

Ref 519ead4a

Signed-off-by: Asad Sajjad Ahmed <asadsa@varnish-software.com>

Signed-off-by: Asad Sajjad Ahmed <asadsa@varnish-software.com>

Signed-off-by: Asad Sajjad Ahmed <asadsa@varnish-software.com>

This should make the code easier to read and stop us from being inconsistent.
Signed-off-by: Asad Sajjad Ahmed <asadsa@varnish-software.com>

For the REGEX type, we now peek ahead after the first CSTR token if a '+'
operator follows and, if yes, create the pattern as a concatenation.

Fixes #3726

The disconnect function should not complain when the server is already
closed by an explicit close.

Saw this failure in vtest:

*    top   TEST ../../../../bin/varnishtest/tests/r01918.vtc starting
...
**   s1    === txresp -nolen -bodylen 10
**** s1    txresp|HTTP/1.1 200 OK\r
**** s1    txresp|\r
**** s1    txresp|!"#$%&'()
**   s1    === close
...
**   s1    Waiting for server (4/-1)
**** s1    Closed
***  s1    shutting fd -1
---- s1    Shutdown failed: Bad file descriptor

fixes regression from 9a20cdfd

It needs to be a generic pointer pointer, because it is initialized as
a pointer to a pointer to an arbitrary struct, yet (void **) is can not
be dereferenced.

Right now, the instance info is not used, but this might change.