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

Fix bug in the readpassphrase(3) function, which can be exposed
by application closing its stdin (i.e. STDIN_FILENO) prior to
calling readpassphrase WITHOUT setting RPP_STDIN. What happens
then is that the readpassphrase would open /dev/tty, and since
file descriptors are reused, the call would return first unused
fd, which is 0 which is also STDIN_FILENO. Then due to the usage
of "input != STDIN_FILENO" in the code to do its logic, that
would result in noecho flags not set on that file descriptor,
which was original issue I've been trying to fix.

In addition to that, the readpassphrase() would leak file
descriptor on its way out, so fix that one as well.

This problem can be tested with:

$ ssh-add - < /tmp/myprivate.key

The password will not be hidden as it should and ktrace will
show:

53326 ssh-add CALL open(0x80142443c,0x100002<O_RDWR|O_CLOEXEC>,<unused>0x165f030)
53326 ssh-add NAMI "/dev/tty"
53326 ssh-add RET open 0
53326 ssh-add CALL sigprocmask(SIG_SETMASK,0x802eb1324,0x7fffffffd5e0)
53326 ssh-add RET sigprocmask 0
53326 ssh-add CALL sigaction(SIGALRM,0x7fffffffd630,0x7fffffffd610)

Instead of:

57690 ssh-add CALL open(0x80142443c,0x100002<O_RDWR|O_CLOEXEC>,<unused>0x165f030)
57690 ssh-add NAMI "/dev/tty"
57690 ssh-add RET open 4
57690 ssh-add CALL ioctl(0x4,TIOCGETA,0x7fffffffd860)
57690 ssh-add RET ioctl 0
57690 ssh-add CALL ioctl(0x4,TIOCSETAF,0x7fffffffd680)
57690 ssh-add RET ioctl 0
57690 ssh-add CALL sigprocmask(SIG_SETMASK,0x802eb1324,0x7fffffffd620)
57690 ssh-add RET sigprocmask 0
57690 ssh-add CALL sigaction(SIGALRM,0x7fffffffd670,0x7fffffffd650)

For the case when the key is read from the file.

Technically this can also be workaround'ed at the application side
by not closing the STDIN_FILENO in the first place, but readpassphrase(3)
doesn't need to make any assumptions about that. Plus the file descriptor
leak confirms that this is an oversight, rather than a deliberate behaviour.

MFC after: 1 week

Switch libc from using _sig{procmask,action,suspend} symbols, which
are aliases for the syscall stubs and are plt-interposed, to the
libc-private aliases of internally interposed sigprocmask() etc.

Since e.g. _sigaction is not interposed by libthr, calling signal()
removes thr_sighandler() from the handler slot etc. The result was
breaking signal semantic and rtld locking.

The added __libc_sigprocmask and other symbols are hidden, they are
not exported and cannot be called through PLT. The setjmp/longjmp
functions for x86 were changed to use direct calls, and since
PIC_PROLOGUE only needed for functional PLT indirection on i386, it is
removed as well.

The PowerPC bug of calling the syscall directly in the setjmp/longjmp
implementation is kept as is.

Reported by: Pete French <petefrench@ingresso.co.uk>
Tested by: Michiel Boland <boland37@xs4all.nl>
Reviewed by: jilles (previous version)
Sponsored by: The FreeBSD Foundation
MFC after: 1 week

libc/gen: small updates to code originating at OpenBSD

arc4random.c
- CVS rev. 1.22
Change arc4random_uniform() to calculate ``2**32 % upper_bound'' as
``-upper_bound % upper_bound''. Simplifies the code and makes it the
same on both ILP32 and LP64 architectures, and also slightly faster on
LP64 architectures by using a 32-bit remainder instead of a 64-bit
remainder.
- CVS rev. 1.23
Spacing

readpassphrase.c
-CVS rev. v 1.24
most obvious unsigned char casts for ctype

Obtained from: OpenBSD
MFC after: 5 days

libc: Use O_CLOEXEC for various internal file descriptors.

This fixes a race condition where another thread may fork() before CLOEXEC
is set, unintentionally passing the descriptor to the child process.

This commit only adds O_CLOEXEC flags to open() or openat() calls where no
fcntl(fd, F_SETFD, FD_CLOEXEC) follows. The separate fcntl() call still
leaves a race window so it should be fixed later.

Sync with OpenBSD, primarily better signal and terminal handling.

Obtained from: OpenBSD
MFC after: 2 weeks

Fix build. I commented out getpass() in readpassphrase.c because the
implementation did not match our manpage description (i.e., it could
return NULL). I mistakenly thought we were still using getpass.c
because, for some reason, CVS never removed it from the tree.

Pointy hat received from: alfred
Kick in the groin to: CVS

Update readpassphrase(3)to the latest revisions. Changes are mainly due
to return value constraints now changing as well as more intelligent
handling of signals.

Obtained from: OpenBSD

fix compilation (include -> #include)

Should also include namespace.h

Submitted by: ru

Change certain syscalls from x to _x.

Prodded by: bde

Introduce readpassphrase(3), a superset of getpass(3). This
comes originally from Todd Miller.

Obtained from: OpenBSD