Zpkgs {tv -> krebs} genid

2 files changed, 23 insertions, 0 deletions

diff --git a/Zpkgs/krebs/default.nix b/Zpkgs/krebs/default.nix
index 88389047..e07b96b5 100644
--- a/Zpkgs/krebs/default.nix
+++ b/Zpkgs/krebs/default.nix
@@ -6,6 +6,7 @@ in
 
 pkgs //
 {
+  genid = callPackage ./genid.nix {};
   github-hosts-sync = callPackage ./github-hosts-sync.nix {};
   github-known_hosts = callPackage ./github-known_hosts.nix {};
   hashPassword = callPackage ./hashPassword.nix {};
diff --git a/Zpkgs/krebs/genid.nix b/Zpkgs/krebs/genid.nix
new file mode 100644
index 00000000..c75bec31
--- /dev/null
+++ b/Zpkgs/krebs/genid.nix
@@ -0,0 +1,22 @@
+{ lib, pkgs, ... }:
+
+pkgs.writeScriptBin "genid" ''
+  #! /bin/sh
+  # usage: genid NAME
+  set -euf
+
+  export PATH=${lib.makeSearchPath "bin" (with pkgs; [
+    bc
+    coreutils
+  ])}
+
+  name=$1
+  hash=$(printf %s "$name" | sha1sum | cut -d\  -f1 | tr a-f A-F)
+  echo "
+    min=2^24  # bigger than nobody and nogroup, see <nixos/modules/misc/ids.nix>
+              # and some spare for stuff like lxd.
+    max=2^32  # see 2^(8*sizeof(uid_t))
+    ibase=16
+    ($hash + min) % max
+  " | bc
+''