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

msdosfs: Prevent buffer overflow when expanding win95 names

In win2unixfn() we expand Windows 95 style long names. In some cases that
requires moving the data in the nbp->nb_buf buffer backwards to make room. That
code failed to check for overflows, leading to a stack overflow in win2unixfn().

We now check for this event, and mark the entire conversion as failed in that
case. This means we present the 8 character, dos style, name instead.

PR: 204643
Differential Revision: https://reviews.freebsd.org/D6015

- Add idempotency guards so the structures can be used in other utilities.
- Update bpb structs with reserved fields.
- In direntry struct join deName with deExtension. Although a
fix was attempted in the past, these fields were being overflowed,
Now this is consistent with the spec, and we can now share the
WinChksum code with NetBSD.

Submitted by: Pedro F. Giffuni <giffunip tutopia com>
Mostly obtained from: NetBSD
Reviewed by: bde
MFC after: 2 weeks

Fix races in msdosfs_lookup() and msdosfs_readdir(). These functions
can easily block in bread(), and then there was nothing to prevent the
static buffer (nambuf_{ptr,len,last_id}) being clobbered by another
thread.

The effects of the bug seem to have been limited to failed lookups and
mangled names in readdir(), since Giant locking provides enough
serialization to prevent concurrent calls to the functions that access
the buffer. They were very obvious for multiple concurrent tree walks,
especially with a small cluster size.

The bug was introduced in msdosfs_conv.c 1.34 and associated changes,
and is in all releases starting with 5.2.

The fix is to allocate the buffer as a local variable and pass around
pointers to it like "_r" functions in libc do. Stack use from this
is large but not too large. This also fixes a memory leak on module
unload.

Reviewed by: kib
Approved by: re (kensmith)

Replace slightly crummy fattime<->timespec conversion functions.

Do not assume that `char direntry::deExtension[3]' starts right after
`char direntry::deName[8]' and access deExtension[] explicitly.

Found by: Coverity Prevent(tm)
CID: 350, 351, 352

/* -> /*- for copyright notices, minor format tweaks as necessary

Use size_t or ssize_t wherever appropriate instead of casting from int *
to size_t *, which is incorrect because they may have different widths.
This caused some subtle forms of corruption, the mostly frequently
reported one being that the last character of a filename was sometimes
duplicated on amd64.

Forced commit to note that my previous commit was a Darwin merge.

Fixed some style bugs in previous commit. Mainly, forward-declare
struct msdosfsmount so that this file has the same prerequisites as
it used to. The new prerequistite was a meta-style bug. It required
many style bugs (unsorted includes ...) elsewhere.

Formatted prototypes in KNF. Resisted urge to sort all the prototypes,
to minimise differences with NetBSD. (NetBSD has reformatted the
prototypes but has not sorted them and still uses __P(()).)

- Support for multibyte charsets in LIBICONV.
- CD9660_ICONV, NTFS_ICONV and MSDOSFS_ICONV kernel options
(with corresponding modules).
- kiconv(3) for loadable charset conversion tables support.

Submitted by: Ryuichiro Imura <imura@ryu16.org>

Remove __P.

Change #ifdef KERNEL to #ifdef _KERNEL in the public headers. "KERNEL"
is an application space macro and the applications are supposed to be free
to use it as they please (but cannot). This is consistant with the other
BSD's who made this change quite some time ago. More commits to come.

$Id$ -> $FreeBSD$

Support NT VFAT lower case flags.

PR: 8383
(Mostly) Submitted by: Carl Mascott <cmascott@world.std.com>

Fixes for some bugs in the VFAT/FAT32 support:

- 'mv longnamedfile1 longnamedfile2' would cause longnamedfile2 to lose its
long name.
- Long names have trailing spaces/dots stripped for lookup as well as
assignment.
- A lockup when the mdsosfs was accessed from within the Linux emulator is fixed.
- A bug whereby long filenames were recognised by Microsoft operating systems but
not FreeBSD is fixed.

Submitted by: Dmitrij Tejblum <dima@tejblum.dnttm.rssi.ru>

Back out "always view in lowercase" part
Return to previous variant "comparing in lowercase" in winChkName

Implement loadable DOS<->local conversion tables for DOS names
Always create DOS name in uppercase
Always view DOS name in lowercase

Implement loadable upper->lower local conversion table

Reduce new arguments number added in my changes

Add Unicode support to winChkName, now lookup works!

Implement loadable local<->unicode file names conversion
Note: it produce correct names only for Win95, DOS names are still
incorrect and need similar work
mount_msdos support coming soon

Update MSDOSFS code using NetBSD's msdosfs as a guide to support
FAT32 partitions. Unfortunately, we looked around here at
Walnut Creek CDROM for any newer FAT32-supporting versions
of Win95 and we were unsuccessful; only the older stuff here.
So this is untested beyond simply making sure it compiles and
someone with access to an actual FAT32 fs will have
to let us know how well it actually works.
Submitted by: Dmitrij Tejblum <dima@tejblum.dnttm.rssi.ru>
Obtained from: NetBSD

Back out part 1 of the MCFH that changed $Id$ to $FreeBSD$. We are not
ready for it yet.

Make the long-awaited change from $Id$ to $FreeBSD$

This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.

Remove trailing whitespace.

Added msdosfs.

Obtained from: NetBSD