1 files changed, 46 insertions, 0 deletions
diff --git a/pkgs/profpatsch/execline/symlink.nix b/pkgs/profpatsch/execline/symlink.nix
new file mode 100644
index 00000000..c6a311d8
--- /dev/null
+++ b/pkgs/profpatsch/execline/symlink.nix
@@ -0,0 +1,46 @@
+{ lib, s6-portable-utils, coreutils, runExecline }:
+# DrvPath :: path relative to the derivation
+# AbsPath :: absolute path in the store
+#    Name
+# -> List (Symlink { dest: DrvPath, orig: AbsPath })
+# -> Drv
+name: links:
+
+let
+  toNetstring = s:
+    "${toString (builtins.stringLength s)}:${s},";
+
+in
+runExecline name {
+  derivationArgs = {
+    pathTuples = lib.concatMapStrings
+      ({dest, orig}: toNetstring
+        (toNetstring dest + (toNetstring orig)))
+      links;
+    passAsFile = [ "pathTuples" ];
+    # bah! coreutils just for cat :(
+    PATH = lib.makeBinPath [ s6-portable-utils ];
+  };
+} [
+  "importas" "-ui" "p" "pathTuplesPath"
+  "importas" "-ui" "out" "out"
+  "forbacktickx" "-d" "" "destorig" [ "${coreutils}/bin/cat" "$p" ]
+    "importas" "-ui" "do" "destorig"
+    "multidefine" "-d" "" "$do" [ "destsuffix" "orig" ]
+    "define" "dest" ''''${out}/''${destsuffix}''
+
+    # this call happens for every file, not very efficient
+    "foreground" [
+      "backtick" "-n" "d" [ "s6-dirname" "$dest" ]
+      "importas" "-ui" "d" "d"
+      "s6-mkdir" "-p" "$d"
+    ]
+
+    "ifthenelse" [ "s6-test" "-L" "$orig" ] [
+      "backtick" "-n" "res" [ "s6-linkname" "-f" "$orig" ]
+      "importas" "-ui" "res" "res"
+      "s6-ln" "-fs" "$res" "$dest"
+    ] [
+      "s6-ln" "-fs" "$orig" "$dest"
+    ]
+]