Export sbuf_drain to orchestrate lock and drain action

While exporting large amounts of data to a sysctl
request, datastructures may need to be locked.

Exporting the sbuf_drain function allows the
coordination between drain events and held
locks, to avoid stalls.

PR: 254333
Reviewed By: jhb
MFC after: 2 weeks
Sponsored by: NetApp, Inc.
Differential Revision: https://reviews.freebsd.org/D29481

(cherry picked from commit c804c8f2c58ba42d476de07fbceff9ac4dd95f0e)

Git Hash: 6ab67f3b20ac44e9e9741bd0bdf557c3aa118d32
Git Author: rscheff@FreeBSD.org

Revert r330897:

This was intended to be a non-functional change. It wasn't. The commit
message was thus wrong. In addition it broke arm, and merged crypto
related code.

Revert with prejudice.

This revert skips files touched in r316370 since that commit was since
MFCed. This revert also skips files that require $FreeBSD$ property
changes.

Thank you to those who helped me get out of this mess including but not
limited to gonzo, kevans, rgrimes.

Requested by: gjb (re)

Partial merge of the SPDX changes

These changes are incomplete but are making it difficult
to determine what other changes can/should be merged.

No objections from: pfg

MFC r307873,r314397,r314399,r314419,r314420,r314533,r316553:

r307873 (by marcel):

Include <stdarg.h> instead of <machine/stdarg.h> when compiled as
part of libsbuf. The former is the standard header, and allows us
to compile libsbuf on macOS/linux.

r314397 (by scottl):

Implement sbuf_prf(), which takes an sbuf and outputs it
to stdout in the non-kernel case and to the console+log
in the kernel case. For the kernel case it hooks the
putbuf() machinery underneath printf(9) so that the buffer
is written completely atomically and without a copy into
another temporary buffer. This is useful for fixing
compound console/log messages that become broken and
interleaved when multiple threads are competing for the
console.

r314399 (by scottl):

Add prototype for sbuf_putbuf()

r314419 (by jkim):

Include stdio.h to fix libsbuf build.

r314420 (by scottl):

Provide a comment on why stdio.h needs to be included.

r314533 (by scottl):

Expose the sbuf_putbuf() symbol to libsbuf. There are a few other symbols
that are present but not exposed, like get/set/clear flags, not sure if they
need to be exposed at this point.

r316553:

sbuf(3): expose sbuf_{clear,get,set}_flags(3) via libsbuf

These functions were added to sbuf(9) in r279992, but never
exposed to userspace. Expose them now so they can be used/tested.

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Add support for reading MAM attributes to camcontrol(8) and libcam(3).

MAM is Medium Auxiliary Memory and is most commonly found as flash
chips on tapes.

This includes support for reading attributes and decoding most
known attributes, but does not yet include support for writing
attributes or reporting attributes in XML format.

libsbuf/Makefile:
Add subr_prf.c for the new sbuf_hexdump() function. This
function is essentially the same function.

libsbuf/Symbol.map:
Add a new shared library minor version, and include the
sbuf_hexdump() function.

libsbuf/Version.def:
Add version 1.4 of the libsbuf library.

libutil/hexdump.3:
Document sbuf_hexdump() alongside hexdump(3), since it is
essentially the same function.

camcontrol/Makefile:
Add attrib.c.

camcontrol/attrib.c:
Implementation of READ ATTRIBUTE support for camcontrol(8).

camcontrol/camcontrol.8:
Document the new 'camcontrol attrib' subcommand.

camcontrol/camcontrol.c:
Add the new 'camcontrol attrib' subcommand.

camcontrol/camcontrol.h:
Add a function prototype for scsiattrib().

share/man/man9/sbuf.9:
Document the existence of sbuf_hexdump() and point users to
the hexdump(3) man page for more details.

sys/cam/scsi/scsi_all.c:
Add a table of known attributes, text descriptions and
handler functions.

Add a new scsi_attrib_sbuf() function along with a number
of other related functions that help decode attributes.

scsi_attrib_ascii_sbuf() decodes ASCII format attributes.

scsi_attrib_int_sbuf() decodes binary format attributes, and
will pass them off to scsi_attrib_hexdump_sbuf() if they're
bigger than 8 bytes.

scsi_attrib_vendser_sbuf() decodes the vendor and drive
serial number attribute.

scsi_attrib_volcoh_sbuf() decodes the Volume Coherency
Information attribute that LTFS writes out.

sys/cam/scsi/scsi_all.h:
Add a number of attribute-related structure definitions and
other defines.

Add function prototypes for all of the functions added in
scsi_all.c.

sys/kern/subr_prf.c:
Add a new function, sbuf_hexdump(). This is the same as
the existing hexdump(9) function, except that it puts the
result in an sbuf.

This also changes subr_prf.c so that it can be compiled in
userland for includsion in libsbuf.

We should work to change this so that the kernel hexdump
implementation is a wrapper around sbuf_hexdump() with a
statically allocated sbuf with a drain. That will require
a drain function that goes to the kernel printf() buffer
that can take a non-NUL terminated string as input.
That is because an sbuf isn't NUL-terminated until it is
finished, and we don't want to finish it while we're still
using it.

We should also work to consolidate the userland hexdump and
kernel hexdump implemenatations, which are currently
separate. This would also mean making applications that
currently link in libutil link in libsbuf.

sys/sys/sbuf.h:
Add the prototype for sbuf_hexdump(), and add another copy
of the hexdump flag values if they aren't already defined.

Ideally the flags should be defined in one place but the
implemenation makes it difficult to do properly. (See
above.)

Sponsored by: Spectra Logic Corporation
MFC after: 1 week

Add a new flag, SBUF_INCLUDENUL, and new get/set/clear functions for flags.

The SBUF_INCLUDENUL flag causes the nulterm byte at the end of the string
to be counted in the length of the data. If copying the data using the
sbuf_data() and sbuf_len() functions, or if writing it automatically with
a drain function, the net effect is that the nulterm byte is copied along
with the rest of the data.

Unbreak the ABI by reverting r268494 until the compat shims are provided

Implement Short/Small String Optimization in SBUF(9) and change lengths and
positions in the API from ssize_t and int to size_t.

CR: D388
Approved by: des, bapt

Add sbuf_start_section() and sbuf_end_section() functions, which can
be used for automatic section alignment.

Discussed with: kib
Reviewed by: kib
MFC after: 1 month

Change the length quantities of sbufs to be ssize_t rather than int.

Constify a couple of arguments.

Replace sbuf_overflowed() with sbuf_error(), which returns any error
code associated with overflow or with the drain function. While this
function is not expected to be used often, it produces more information
in the form of an errno that sbuf_overflowed() did.

Add drain functionality to sbufs. The drain is a function that is
called when the sbuf internal buffer is filled. For kernel sbufs with a
drain, the internal buffer will never be expanded. For userland sbufs
with a drain, the internal buffer may still be expanded by
sbuf_[v]printf(3).

Sbufs now have three basic uses:
1) static string manipulation. Overflow is marked.
2) dynamic string manipulation. Overflow triggers string growth.
3) drained string manipulation. Overflow triggers draining.

In all cases the manipulation is 'safe' in that overflow is detected and
managed.

Reviewed by: phk (the previous version)

Add sbuf_new_auto as a shortcut for the very common case of creating a
completely dynamic sbuf.

Obtained from: Varnish
MFC after: 2 weeks

Switch to simplified BSD license (with phk's approval), plus whitespace
and style(9) cleanup.

Have sbuf_bcat() and sbuf_bcpy() take a const void * instead of a
const char *, since callers are likely to pass in pointers to all
kinds of structs and whatnot.

Add the new function "sbuf_done()" which returns non-zero if the sbuf is
finished.

This allows sbufs to be used for request/response scenarioes without
needing additional communication flags.

Sponsored by: DARPA & NAI Labs.

o Merge <machine/ansi.h> and <machine/types.h> into a new header
called <machine/_types.h>.
o <machine/ansi.h> will continue to live so it can define MD clock
macros, which are only MD because of gratuitous differences between
architectures.
o Change all headers to make use of this. This mainly involves
changing:
#ifdef _BSD_FOO_T_
typedef _BSD_FOO_T_ foo_t;
#undef _BSD_FOO_T_
#endif
to:
#ifndef _FOO_T_DECLARED
typedef __foo_t foo_t;
#define _FOO_T_DECLARED
#endif

Concept by: bde
Reviewed by: jake, obrien

Replace spaces after #defines with tabs; this makes all #defines
consistent in their adherence with style(9).

* Implement SBUF_AUTOEXTEND flag; sbufs created with this flag are
automatically extended to prevent overflow.
* Added sbuf_vprintf(); sbuf_printf() is now just a wrapper around
sbuf_vprintf().
* Include <stdio.h> and <string.h> when building libsbuf to silence
WARNS=4 warnings.

Reviewed by: des

Reduce namespace pollution by removing argument names from prototypes.

Add a couple of API functions I need for my pseudofs WIP. Documentation
will follow when I've decided whether to keep this API or ditch it in
favor of something slightly more subtle.

Add printf format checking to sbuf_printf()

Submitted by: Harti Brandt <brandt@fokus.gmd.de

Constify the format string.

Submitted by: Mike Barcroft <mike@q9media.com>

Add sbuf_copyin(). Also add 'b' variants of sbuf_{cat,copyin,cpy}() which
ignore NUL bytes in the source string.

sbuf_new(9) now returns a struct sbuf * instead of an int. If the caller
does not provide a struct sbuf, sbuf_new(9) will allocate one and return
a pointer to it.

Rewrite of the CAM error recovery code.

Some of the major changes include:

- The SCSI error handling portion of cam_periph_error() has
been broken out into a number of subfunctions to better
modularize the code that handles the hierarchy of SCSI errors.
As a result, the code is now much easier to read.

- String handling and error printing has been significantly
revamped. We now use sbufs to do string formatting instead
of using printfs (for the kernel) and snprintf/strncat (for
userland) as before.

There is a new catchall error printing routine,
cam_error_print() and its string-based counterpart,
cam_error_string() that allow the kernel and userland
applications to pass in a CCB and have errors printed out
properly, whether or not they're SCSI errors. Among other
things, this helped eliminate a fair amount of duplicate code
in camcontrol.

We now print out more information than before, including
the CAM status and SCSI status and the error recovery action
taken to remedy the problem.

- sbufs are now available in userland, via libsbuf. This
change was necessary since most of the error printing code
is shared between libcam and the kernel.

- A new transfer settings interface is included in this checkin.
This code is #ifdef'ed out, and is primarily intended to aid
discussion with HBA driver authors on the final form the
interface should take. There is example code in the ahc(4)
driver that implements the HBA driver side of the new
interface. The new transfer settings code won't be enabled
until we're ready to switch all HBA drivers over to the new
interface.

src/Makefile.inc1,
lib/Makefile: Add libsbuf. It must be built before libcam,
since libcam uses sbuf routines.

libcam/Makefile: libcam now depends on libsbuf.

libsbuf/Makefile: Add a makefile for libsbuf. This pulls in the
sbuf sources from sys/kern.

bsd.libnames.mk: Add LIBSBUF.

camcontrol/Makefile: Add -lsbuf. Since camcontrol is statically
linked, we can't depend on the dynamic linker
to pull in libsbuf.

camcontrol.c: Use cam_error_print() instead of checking for
CAM_SCSI_STATUS_ERROR on every failed CCB.

sbuf.9: Change the prototypes for sbuf_cat() and
sbuf_cpy() so that the source string is now a
const char *. This is more in line wth the
standard system string functions, and helps
eliminate warnings when dealing with a const
source buffer.

Fix a typo.

cam.c: Add description strings for the various CAM
error status values, as well as routines to
look up those strings.

Add new cam_error_string() and
cam_error_print() routines for userland and
the kernel.

cam.h: Add a new CAM flag, CAM_RETRY_SELTO.

Add enumerated types for the various options
available with cam_error_print() and
cam_error_string().

cam_ccb.h: Add new transfer negotiation structures/types.

Change inq_len in the ccb_getdev structure to
be "reserved". This field has never been
filled in, and will be removed when we next
bump the CAM version.

cam_debug.h: Fix typo.

cam_periph.c: Modularize cam_periph_error(). The SCSI error
handling part of cam_periph_error() is now
in camperiphscsistatuserror() and
camperiphscsisenseerror().

In cam_periph_lock(), increase the reference
count on the periph while we wait for our lock
attempt to succeed so that the periph won't go
away while we're sleeping.

cam_xpt.c: Add new transfer negotiation code. (ifdefed
out)

Add a new function, xpt_path_string(). This
is a string/sbuf analog to xpt_print_path().

scsi_all.c: Revamp string handing and error printing code.
We now use sbufs for much of the string
formatting code. More of that code is shared
between userland the kernel.

scsi_all.h: Get rid of SS_TURSTART, it wasn't terribly
useful in the first place.

Add a new error action, SS_REQSENSE. (Send a
request sense and then retry the command.)
This is useful when the controller hasn't
performed autosense for some reason.

Change the default actions around a bit.

scsi_cd.c,
scsi_da.c,
scsi_pt.c,
scsi_ses.c: SF_RETRY_SELTO -> CAM_RETRY_SELTO. Selection
timeouts shouldn't be covered by a sense flag.

scsi_pass.[ch]: SF_RETRY_SELTO -> CAM_RETRY_SELTO.

Get rid of the last vestiges of a read/write
interface.

libkern/bsearch.c,
sys/libkern.h,
conf/files: Add bsearch.c, which is needed for some of the
new table lookup routines.

aic7xxx_freebsd.c: Define AHC_NEW_TRAN_SETTINGS if
CAM_NEW_TRAN_CODE is defined.

sbuf.h,
subr_sbuf.c: Add the appropriate #ifdefs so sbufs can
compile and run in userland.

Change sbuf_printf() to use vsnprintf()
instead of kvprintf(), which is only available
in the kernel.

Change the source string for sbuf_cpy() and
sbuf_cat() to be a const char *.

Add __BEGIN_DECLS and __END_DECLS around
function prototypes since they're now exported
to userland.

kdump/mkioctls: Include stdio.h before cam.h since cam.h now
includes a function with a FILE * argument.

Submitted by: gibbs (mostly)
Reviewed by: jdp, marcel (libsbuf makefile changes)
Reviewed by: des (sbuf changes)
Reviewed by: ken

Add sbuf_clear() and sbuf_overflowed().
Move the helper macros from sbuf.h to sbuf.c
Use ints instead of size_ts.
Relax the requirements for sbuf_finish(): it is now possible to finish an
overflowed buffer.
Make sbuf_len() return -1 instead of 0 if the sbuf overflowed.

Requested by: gibbs

String buffer API