ktrace: log genio events on failed write

Visibility into the contents of the buffer when a write(2) has failed
can be immensely useful in debugging IPC issues -- pushing this to
discuss the idea, or maybe an alternative where we can set a flag like
KTRFAC_ERRIO to enable it.

When a genio event is potentially raised after an error, currently we'll
just free the uio and return. However, such data can be useful when
debugging communication between processes to, e.g., understand what the
remote side should have grabbed before closing a pipe. Tap out the
entire buffer on failure rather than simply discarding it.

Reviewed by: kib, markj
Differential Revision: https://reviews.freebsd.org/D43799

sys: Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

sctp: ansify

Sponsored by: Rubicon Communications, LLC ("Netgate")

Fixup build after recent getsock changes

Add getsock

All but one consumers of getsock_cap only pass 4 arguments.
Take advantage of it.

Convert remaining cap_rights_init users to cap_rights_init_one

semantic patch:

@@

expression rights, r;

@@

- cap_rights_init(&rights, r)
+ cap_rights_init_one(&rights, r)

Cleanup, no functional change intended.

This file is only compiled if INET or INET6 is defined. So there
is no need for checking that.

Reviewed by: markj
Differential Revision: https://reviews.freebsd.org/D25635

(Re)activate SCTP system calls when compiling SCTP support into the kernel
r363079 introduced the possibility of loading the SCTP stack as a module in
addition to compiling it into the kernel. As part of this, the registration
of the system calls was removed and put into the loading of the module.
Therefore, the system calls are not registered anymore when compiling the
SCTP into the kernel. This patch addresses that.

Reviewed by: markj
Differential Revision: https://reviews.freebsd.org/D25632

Provide support for building SCTP as a loadable module.

With this change, a kernel compiled with "options SCTP_SUPPORT" and
without "options SCTP" supports dynamic loading of the SCTP stack.

Currently sctp.ko cannot be unloaded since some prerequisite teardown
logic is not yet implemented. Attempts to unload the module will return
EOPNOTSUPP.

Discussed with: tuexen
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D21997

sctp: use new capsicum helpers

netinet silence warnings

Move most of the contents of opt_compat.h to opt_global.h.

opt_compat.h is mentioned in nearly 180 files. In-progress network
driver compabibility improvements may add over 100 more so this is
closer to "just about everywhere" than "only some files" per the
guidance in sys/conf/options.

Keep COMPAT_LINUX32 in opt_compat.h as it is confined to a subset of
sys/compat/linux/*.c. A fake _COMPAT_LINUX option ensure opt_compat.h
is created on all architectures.

Move COMPAT_LINUXKPI to opt_dontuse.h as it is only used to control the
set of compiled files.

Reviewed by: kib, cem, jhb, jtl
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D14941

Correct sysent flags for dynamically loaded syscalls.

Using the https://github.com/google/capsicum-test/ suite, the
PosixMqueue.CapModeForked test was failing due to an ECAPMODE after
calling kmq_notify(). On further inspection, the dynamically
loaded syscall entry was initialized with sy_flags zeroed out, since
SYSCALL_INIT_HELPER() left sysent.sy_flags with the default value.

Add a new helper SYSCALL{,32}_INIT_HELPER_F() which takes an
additional argument to specify the sy_flags value.

Submitted by: Siva Mahadevan <smahadevan@freebsdfoundation.org>
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D11576

Listening sockets improvements.

o Separate fields of struct socket that belong to listening from
fields that belong to normal dataflow, and unionize them. This
shrinks the structure a bit.
- Take out selinfo's from the socket buffers into the socket. The
first reason is to support braindamaged scenario when a socket is
added to kevent(2) and then listen(2) is cast on it. The second
reason is that there is future plan to make socket buffers pluggable,
so that for a dataflow socket a socket buffer can be changed, and
in this case we also want to keep same selinfos through the lifetime
of a socket.
- Remove struct struct so_accf. Since now listening stuff no longer
affects struct socket size, just move its fields into listening part
of the union.
- Provide sol_upcall field and enforce that so_upcall_set() may be called
only on a dataflow socket, which has buffers, and for listening sockets
provide solisten_upcall_set().

o Remove ACCEPT_LOCK() global.
- Add a mutex to socket, to be used instead of socket buffer lock to lock
fields of struct socket that don't belong to a socket buffer.
- Allow to acquire two socket locks, but the first one must belong to a
listening socket.
- Make soref()/sorele() to use atomic(9). This allows in some situations
to do soref() without owning socket lock. There is place for improvement
here, it is possible to make sorele() also to lock optionally.
- Most protocols aren't touched by this change, except UNIX local sockets.
See below for more information.

o Reduce copy-and-paste in kernel modules that accept connections from
listening sockets: provide function solisten_dequeue(), and use it in
the following modules: ctl(4), iscsi(4), ng_btsocket(4), ng_ksocket(4),
infiniband, rpc.

o UNIX local sockets.
- Removal of ACCEPT_LOCK() global uncovered several races in the UNIX
local sockets. Most races exist around spawning a new socket, when we
are connecting to a local listening socket. To cover them, we need to
hold locks on both PCBs when spawning a third one. This means holding
them across sonewconn(). This creates a LOR between pcb locks and
unp_list_lock.
- To fix the new LOR, abandon the global unp_list_lock in favor of global
unp_link_lock. Indeed, separating these two locks didn't provide us any
extra parralelism in the UNIX sockets.
- Now call into uipc_attach() may happen with unp_link_lock hold if, we
are accepting, or without unp_link_lock in case if we are just creating
a socket.
- Another problem in UNIX sockets is that uipc_close() basicly did nothing
for a listening socket. The vnode remained opened for connections. This
is fixed by removing vnode in uipc_close(). Maybe the right way would be
to do it for all sockets (not only listening), simply move the vnode
teardown from uipc_detach() to uipc_close()?

Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D9770

Renumber copyright clause 4

Renumber cluase 4 to 3, per what everybody else did when BSD granted
them permission to remove clause 3. My insistance on keeping the same
numbering for legal reasons is too pedantic, so give up on that point.

Submitted by: Jan Schaumann <jschauma@stevens.edu>
Pull Request: https://github.com/freebsd/freebsd/pull/96

Use getsock_cap() instead of deprecated fgetsock().

Reviewed by: tuexen

capsicum: propagate rights on accept(2)

Descriptor returned by accept(2) should inherits capabilities rights from
the listening socket.

PR: 201052
Reviewed by: emaste, jonathan
Discussed with: many
Differential Revision: https://reviews.freebsd.org/D7724

netinet: for pointers replace 0 with NULL.

These are mostly cosmetical, no functional change.

Found with devel/coccinelle.

Reviewed by: ae. tuexen

Fix two KTRACE related bugs.

Reported by: Coverity
CID: 1018058, 1018060

MFC after: 3 days

Replace struct filedesc argument in getsock_cap with struct thread

This is is a step towards removal of spurious arguments.

fd: remove filedesc argument from fdclose

Just accept a thread instead. This makes it consistent with fdalloc.

No functional changes.

Avoid dynamic syscall overhead for statically compiled modules.

The kernel tracks syscall users so that modules can safely unregister them.

But if the module is not unloadable or was compiled into the kernel, there is
no need to do this.

Achieve this by adding SY_THR_STATIC_KLD macro which expands to SY_THR_STATIC
during kernel build and 0 otherwise.

Reviewed by: kib (previous version)
MFC after: 2 weeks

Move the SCTP syscalls to netinet with the rest of the SCTP code. The
syscalls themselves are tightly coupled with the network stack and
therefore should not be in the generic socket code.

The following four syscalls have been marked as NOSTD so they can be
dynamically registered in sctp_syscalls_init() function:
sys_sctp_peeloff
sys_sctp_generic_sendmsg
sys_sctp_generic_sendmsg_iov
sys_sctp_generic_recvmsg

The syscalls are also set up to be dynamically registered when COMPAT32
option is configured.

As a side effect of moving the SCTP syscalls, getsock_cap needs to be
made available outside of the uipc_syscalls.c source file. A proper
prototype has been added to the sys/socketvar.h header file.

API tests from the SCTP reference implementation have been run to ensure
compatibility. (http://code.google.com/p/sctp-refimpl/source/checkout)

Submitted by: Steve Kiernan <stevek@juniper.net>
Reviewed by: tuexen, rrs
Obtained from: Juniper Networks, Inc.