To be consistent with how the file cursor behaves, the close_fd field is
duplicated in the mmap cursor. If a VUT replaces stdin's file descriptor
with a regular file's fd using dup2(2), we don't want to close it just
because we managed to mmap(2) it.

For some reason we don't use the closefd() macro in the VSL cursor code,
potentially to avoid its underlying assertion in libvarnishapi.

On the other hand we do use it in other places:

    $ git grep -l closefd -- lib/libvarnishapi/
    lib/libvarnishapi/daemon.c
    lib/libvarnishapi/vsm.c

So maybe in a subsequent change `(void)close(fd)` statements could turn
into `closefd(&fd)` in vsl_cursor.c to harden those code paths as well.

As pointed out by Dridi, we should rather not make an attempt to
support un-printable socket names, of which the empty name is
the most prominent case.

For all other non-printable cases (e.g. d\0r\0i\0d\0i), we have
no support to pass them in the first place, because we treat
uds paths as NUL-terminated strings.

We use the commonplace @<name> syntax to specify abstract socket names.

Implements #3863

Motivated by #3864

This commit was guided by the cocci patch below, but lines to change
were manually selected.

Motivated by #3864

	--- 8< ---

@@
expression path;
@@

- *path == '/'
+ VUS_is(path)

@@
expression path;
@@

- *path != '/'
+ ! VUS_is(path)

we only forwarded the result from a single read(), which might have
missed information on the actual error.

space for larger XIDs.  Add a version field.

We had three call sites, one with and two without size checking.

Other improvements:

- zero (struct sockaddr_un).sun_path
- set errno if the path argument does not fit

Motivated by: #3863

to anchor patches

As far as I can see, this is only used in the vim->n_ stats, which are,
apparently, not used anywhere.

Check for correct handling of missing pseudo-headers, and invalid
characters.
Signed-off-by: Asad Sajjad Ahmed <asadsa@varnish-software.com>

We should apply the same restrictions on the list of allowed characters inside
H/2 pseudo-headers as we do for H/1. This error is translated into the
headers we send to a backend over H/1.

Failure to do so could permit various exploits against a backend not handling
malformed H/1 requests.
Signed-off-by: Asad Sajjad Ahmed <asadsa@varnish-software.com>

This expands the perfect hash lookup table to be able to match any entry
in the list of well-known headers from tbl/http_headers.h.

Previously only the headers that had a non-zero filter flag section was
kept in the fast match table.

Fixes: VSV00010

We do not need to periodically check the conditions in
obj_extend_condwait() if we ensure that HSH_Cancel() triggers a
wakeup.

Readers on private objects need to ensure they call HSH_Cancel() if
they abort the read, so this is consistent with our requirements.

While we could add a seperate function to the object API for the sole
purpose of signaling a cancel, HSH_Cancel() already calls
ObjWaitState() to syncronize with the backend thread, so adding the
signal there was deemed the simpler solution.

As agreed during bugwash, Martin wants to add back the timeout
as an optinal parameter (default: no timeout).

To override the global parameter on a per-fetch basis.
Signed-off-by: Dridi Boukelmoune <dridi.boukelmoune@gmail.com>

It pauses the fetch progress when clients are lagging behind for
uncacheable streaming deliveries.
Signed-off-by: Dridi Boukelmoune <dridi.boukelmoune@gmail.com>

Signed-off-by: Dridi Boukelmoune <dridi.boukelmoune@gmail.com>

This clarifies which length this field is about.

Better diff with the --word-diff --word-diff-regex='\w+' options.
Signed-off-by: Dridi Boukelmoune <dridi.boukelmoune@gmail.com>

(May not work due to termcap/terminfo differences)

Due to string folding, I expect this change to be fully backwards compatible
- even with std.integert(req.xid) as proven by the vtcs which I am about to
change.