diff --git a/lib/libc/gen/getentropy.3 b/lib/libc/gen/getentropy.3 index dae17cc1b5c1..83812c6c7a92 100644 --- a/lib/libc/gen/getentropy.3 +++ b/lib/libc/gen/getentropy.3 @@ -1,86 +1,86 @@ .\" $OpenBSD: getentropy.2,v 1.8 2015/01/31 00:20:12 schwarze Exp $ .\" .\" Copyright (c) 2018 Conrad Meyer .\" 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. .\" .\" $FreeBSD$ .\" .Dd February 24, 2018 .Dt GETENTROPY 3 .Os .Sh NAME .Nm getentropy .Nd get entropy .Sh LIBRARY .Lb libc .Sh SYNOPSIS .In unistd.h .Ft int .Fn getentropy "void *buf" "size_t buflen" .Sh DESCRIPTION .Fn getentropy fills a buffer with high-quality random data. .Pp The maximum .Fa buflen permitted is 256 bytes. .Pp If it does not produce an error, .Fn getentropy always provides the requested number of bytes of random data. .Pp Similar to reading from .Pa /dev/urandom just after boot, .Fn getentropy may block until the system has collected enough entropy to seed the CSPRNG. .Sh IMPLEMENTATION NOTES The .Fn getentropy function is implemented using .Xr getrandom 2 . .Sh RETURN VALUES .Rv -std .Sh ERRORS .Fn getentropy will succeed unless: .Bl -tag -width Er .It Bq Er EFAULT The .Fa buf parameter points to an invalid address. .It Bq Er EIO Too many bytes requested, or some other fatal error occurred. .El .Sh SEE ALSO -.Xr arc4random 3 , .Xr getrandom 2 , +.Xr arc4random 3 , .Xr random 4 .Sh STANDARDS .Fn getentropy is non-standard. It is present on .Ox and Linux. .Sh HISTORY The .Fn getentropy function appeared in .Ox 5.6 . The .Fx libc compatibility shim first appeared in .Fx 12.0 .