Add new getentropy() system call. Code and pressure from matthew.

I accepted that he's right (again) to seperate this out from heavy
sysctl API and this will simply a variety of things.  Functionname
is not used by anyone in the ports tree, so we guess we can use it.
Shocking that no application has a function called this.
ok matthew & others who pushed him to start this early on

2 files changed, 57 insertions, 6 deletions

diff --git a/lib/libc/sys/Makefile.inc b/lib/libc/sys/Makefile.inc
index 07ce6e397cb..75b05e4b5ab 100644
--- a/lib/libc/sys/Makefile.inc
+++ b/lib/libc/sys/Makefile.inc
@@ -1,4 +1,4 @@
-#	$OpenBSD: Makefile.inc,v 1.117 2014/03/18 22:36:30 miod Exp $
+#	$OpenBSD: Makefile.inc,v 1.118 2014/06/13 08:26:10 deraadt Exp $
 #	$NetBSD: Makefile.inc,v 1.35 1995/10/16 23:49:07 jtc Exp $
 #	@(#)Makefile.inc	8.1 (Berkeley) 6/17/93
 
@@ -33,7 +33,7 @@ ASM=	__get_tcb.o __getcwd.o __semctl.o __set_tcb.o __syscall.o \
 	fchdir.o fchflags.o fchmod.o fchmodat.o fchown.o \
 	fchownat.o fcntl.o fhopen.o fhstat.o fhstatfs.o \
 	flock.o fpathconf.o fstat.o fstatat.o fstatfs.o \
-	fsync.o futimens.o futimes.o getdents.o getdtablecount.o \
+	fsync.o futimens.o futimes.o getentropy.o getdents.o getdtablecount.o \
 	getegid.o geteuid.o getfh.o getfsstat.o getgid.o \
 	getgroups.o getitimer.o getpeername.o getpgid.o getpgrp.o \
 	getpid.o getppid.o getpriority.o getresgid.o getresuid.o \
@@ -200,10 +200,10 @@ MAN+=	__get_tcb.2 __thrsigdivert.2 __thrsleep.2 _exit.2 accept.2 \
 	access.2 acct.2 adjfreq.2 adjtime.2 bind.2 brk.2 chdir.2 \
 	chflags.2 chmod.2 chown.2 chroot.2 clock_gettime.2 close.2 \
 	closefrom.2 connect.2 dup.2 execve.2 fcntl.2 fhopen.2 flock.2 \
-	fork.2 fsync.2 getdents.2 getdtablecount.2 getfh.2 getfsstat.2 \
-	getgid.2 getgroups.2 getitimer.2 getlogin.2 getpeername.2 \
-	getpgrp.2 getpid.2 getpriority.2 getrlimit.2 getrtable.2 \
-	getrusage.2 getsid.2 getsockname.2 getsockopt.2 \
+	fork.2 fsync.2 getentropy.2 getdents.2 getdtablecount.2 \
+	getfh.2 getfsstat.2 getgid.2 getgroups.2 getitimer.2 getlogin.2 \
+	getpeername.2 getpgrp.2 getpid.2 getpriority.2 getrlimit.2 \
+	getrtable.2 getrusage.2 getsid.2 getsockname.2 getsockopt.2 \
 	gettimeofday.2 getuid.2 intro.2 ioctl.2 issetugid.2 \
 	kill.2 kqueue.2 ktrace.2 link.2 listen.2 lseek.2 madvise.2 \
 	mincore.2 minherit.2 mkdir.2 mkfifo.2 mknod.2 mlock.2 \
diff --git a/lib/libc/sys/getentropy.2 b/lib/libc/sys/getentropy.2
new file mode 100644
index 00000000000..be96820df04
--- /dev/null
+++ b/lib/libc/sys/getentropy.2
@@ -0,0 +1,51 @@
+.\"	$OpenBSD: getentropy.2,v 1.1 2014/06/13 08:26:10 deraadt Exp $
+.\"
+.\" Copyright (c) 2014 Theo de Raadt
+.\"
+.\" Permission to use, copy, modify, and distribute this software for any
+.\" purpose with or without fee is hereby granted, provided that the above
+.\" copyright notice and this permission notice appear in all copies.
+.\"
+.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+.\"
+.Dd $Mdocdate: June 13 2014 $
+.Dt GETENTROPY 2
+.Os
+.Sh NAME
+.Nm getentropy
+.Nd get entropy
+.Sh SYNOPSIS
+.Fd #include <unistd.h>
+.Ft ssize_t
+.Fn getentropy "char *buf" "size_t buflen"
+.Sh DESCRIPTION
+.Nm
+returns a buffer of high-quality seed-grade entropy.
+.Pp
+This is typically used to seed a process-context generator
+like
+.Xr arc4random 3 .
+.Sh ERRORS
+.Nm
+.Fn setlogin
+will succeed unless:
+.Bl -tag -width Er
+.It Bq Er EFAULT
+The
+.Fa name
+parameter points to an
+invalid address.
+.El
+.Sh SEE ALSO
+.Xr arc4random 3
+.Sh HISTORY
+The
+.Nm
+function appeared in
+.Ox 5.6 .