getentropy.3c revision 9d12795f87b63c2e39e87bff369182edd34677d3
$OpenBSD: getentropy.2,v 1.7 2014/12/10 19:19:00 schwarze Exp $
Copyright (c) 2014 Theo de Raadt
Copyright (c) 2015 Joyent, Inc.
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 "Dec 31, 2014" .Dt GETENTROPY 3C .Os .Sh NAME .Nm getentropy .Nd get entropy .Sh SYNOPSIS .Fd #include <unistd.h> .Ft int .Fn getentropy "void *buf" "size_t buflen" .Sh DESCRIPTION .Nm fills a buffer with high-quality entropy, which can be used as input for process-context pseudorandom generators like .Xr arc4random 3C .
Copyright (c) 2014 Theo de Raadt
Copyright (c) 2015 Joyent, Inc.
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 "Dec 31, 2014" .Dt GETENTROPY 3C .Os .Sh NAME .Nm getentropy .Nd get entropy .Sh SYNOPSIS .Fd #include <unistd.h> .Ft int .Fn getentropy "void *buf" "size_t buflen" .Sh DESCRIPTION .Nm fills a buffer with high-quality entropy, which can be used as input for process-context pseudorandom generators like .Xr arc4random 3C .
p The maximum buffer size permitted is 256 bytes. If .Va buflen exceeds this, an error of .Er EIO will be indicated.
p .Nm is not intended for regular code; please use the .Xr arc4random 3C family of functions instead. .Sh RETURN VALUES .Rv -std .Sh ERRORS .Fn getentropy will succeed unless: l -tag -width Er t Er EFAULT The .Fa buf parameter points to an invalid address. t Er EIO Too many bytes requested, or some other fatal error occurred. .El .Sh INTERFACE STABILITY .Sy Comitted .Sh MT-LEVEL .Sy Async-Signal-Safe .Sh SEE ALSO .Xr arc4random 3C .Xr attributes 5