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mirror of https://github.com/urbit/shrub.git synced 2024-12-27 14:17:13 +03:00
shrub/pkg/ent
Brendan Hay ce3cbf0857
build: rework all nix expressions to support hercules-ci builds
This also removes nixcrpkgs and OSX cross compilation in favour of
compiling on the target. x86_64/musl targets are still supported
on Linux.

All sources are now managed via niv (see nix/sources.json) and Haskell
package sets are provided/organised via IOHK's haskell.nix.

Some effort has been made to expose similar top-level attributes for
development, but in some cases there have been changes. Please see
the comments in the top-level default.nix and ci.nix files for usage.
2020-10-27 13:55:49 +01:00
..
.gitignore Add 'pkg/ent/' from commit '31ac2913f14c6f7631f5792ad942605fb2d9fb87' 2019-03-04 16:49:14 -08:00
configure Add 'pkg/ent/' from commit '31ac2913f14c6f7631f5792ad942605fb2d9fb87' 2019-03-04 16:49:14 -08:00
ent.c Add 'pkg/ent/' from commit '31ac2913f14c6f7631f5792ad942605fb2d9fb87' 2019-03-04 16:49:14 -08:00
ent.h Add 'pkg/ent/' from commit '31ac2913f14c6f7631f5792ad942605fb2d9fb87' 2019-03-04 16:49:14 -08:00
LICENSE Add 'pkg/ent/' from commit '31ac2913f14c6f7631f5792ad942605fb2d9fb87' 2019-03-04 16:49:14 -08:00
Makefile Add 'pkg/ent/' from commit '31ac2913f14c6f7631f5792ad942605fb2d9fb87' 2019-03-04 16:49:14 -08:00
README.md Add 'pkg/ent/' from commit '31ac2913f14c6f7631f5792ad942605fb2d9fb87' 2019-03-04 16:49:14 -08:00
shell.nix build: rework all nix expressions to support hercules-ci builds 2020-10-27 13:55:49 +01:00
test.c Add 'pkg/ent/' from commit '31ac2913f14c6f7631f5792ad942605fb2d9fb87' 2019-03-04 16:49:14 -08:00

libent

libent is a cross-platform wrapper around getentropy(2). It exports one symbol, ent_getentropy. If getentropy is available, then it's just a shim around that. Otherwise, it uses getrandom(2) (available since kernel 3.17) on Linux, or /dev/urandom on other *nix.

Building and Testing

./configure
make
make test
PREFIX=/usr/local make install

Why?

getentropy is the wave of the future. It's the correct API for generating small amounts of entropy to create cryptographic keys or seed PRNGs. It's good and reasonable and true, it's on Linux, *BSD, and OS X, and it only took us fifty years of UNIX to get here.

Sadly, it only just arrived, so nobody has it yet. It didn't land in Linux until glibc 2.25, which seems to only have made it into Debian 10.

Once getentropy is everywhere you care about, you can just do a s/ent_//g on all the call sites and discard this shim.

This project began because Urbit's entropy-generation function was bothering me. Then it got out of hand.

References