From: Ismaël Bouya <ismael.bouya@normalesup.org>
Date: Wed, 19 May 2021 16:38:50 +0000 (+0200)
Subject: Add stdenv_prefix
X-Git-Url: https://git.immae.eu/?a=commitdiff_plain;h=b4e94e5ffeb834f96c5f3338c36b22fc13bd0cee;p=perso%2FImmae%2FConfig%2FNixies.git

Add stdenv_prefix
---

diff --git a/stdenv_prefix/example.nix b/stdenv_prefix/example.nix
new file mode 100644
index 0000000..0d4aa65
--- /dev/null
+++ b/stdenv_prefix/example.nix
@@ -0,0 +1,51 @@
+{ storepath_length ? 30, storepath_chunks ? 4, pkgs ? import <nixpkgs> {
+  stdenvStages = { config, overlays, localSystem, ... }@args: (import <nixpkgs/pkgs/stdenv> args) ++ [
+    (previousStage: {
+      inherit config overlays;
+      stdenv = let
+        toPreHook = withAppendOut: ''
+              storepath_length=${toString storepath_length}
+              storepath_chunks=${toString storepath_chunks}
+          '' + builtins.readFile ./prehook.sh + (pkgs.lib.optionalString withAppendOut ''
+              appendOut
+          '');
+        newlibunistring = previousStage.libunistring.overrideAttrs (attrs: {
+          preHook = attrs.preHook or "" + (toPreHook true);
+          am_cv_func_iconv_works = "yes";
+        });
+        newlibidn2 = (previousStage.libidn2.override { libunistring = newlibunistring; }).overrideAttrs (attrs: {
+          preHook = attrs.preHook or "" + (toPreHook true);
+          postFixup = ''
+            ${previousStage.nukeReferences}/bin/nuke-refs -e $(cat ${newlibunistring}/nix-support/new-out)/lib \
+              "$out"/lib/lib*.so.*.*
+          '';
+        });
+        overridenCallPackage = p: a: previousStage.callPackage p (a // { libidn2 = newlibidn2;});
+
+        newlibc = (previousStage."${localSystem.libc}".override { callPackage = overridenCallPackage; }).overrideAttrs(old: {
+          preHook = old.preHook or "" + (toPreHook true);
+        });
+        newbintools = (previousStage.binutils.override { libc = newlibc; }).overrideAttrs(old: {
+          postFixup = old.postFixup + ''
+            newlibcout=$(cat ${newlibc}/nix-support/new-out)
+            sed -i -e "s@${newlibc}@$newlibcout@g" $out/nix-support/*
+          '';
+        });
+        newStdenv = previousStage.stdenv.override {
+          allowedRequisites = null;
+          extraAttrs.bintools = newbintools;
+          cc = previousStage.gcc.override({ bintools = newbintools; libc = newlibc; });
+          overrides = self: super: rewriteMap (previousStage.stdenv.overrides self super) // {
+            ${localSystem.libc} = newlibc;
+          };
+          preHook = previousStage.stdenv.preHook + ''
+              libc_path=${newlibc}
+            '' + (toPreHook false);
+        };
+        rewriteMap = builtins.mapAttrs (n: v: v.override { stdenv = newStdenv; });
+      in
+        newStdenv;
+      })
+    ];
+} }:
+  pkgs.xar
diff --git a/stdenv_prefix/prehook.sh b/stdenv_prefix/prehook.sh
new file mode 100644
index 0000000..db9a4d2
--- /dev/null
+++ b/stdenv_prefix/prehook.sh
@@ -0,0 +1,98 @@
+count_chunks() {
+  elements="${1//[^\/]}"
+  echo $(( "${#elements}" ))
+}
+
+oldout=$out
+prefix_chunks=$(count_chunks $NIX_STORE)
+
+: ${storepath_length=${#NIX_STORE}}
+: ${storepath_chunks=$prefix_chunks}
+
+if [ "$storepath_chunks" -lt $prefix_chunks ]; then
+  echo "Need to have at least as much path elements as the initial prefix"
+  exit 1
+fi
+
+min_length=$(( ${#NIX_STORE} + 2 * $storepath_chunks - 2 * $prefix_chunks ))
+if [ "$storepath_length" -lt "$min_length" ]; then
+  echo "The storepath length needs to be at least the length of the prefix"
+  exit 1
+fi
+
+if [ "$storepath_chunks" -eq "$prefix_chunks" -a "$storepath_length" -gt "$min_length" ]; then
+  echo "You need at least one more chunk for a non-standard path length"
+  exit 1
+fi
+
+appendOut() {
+  chunk_prefix=$(for (( c=$prefix_chunks ; c < $storepath_chunks ; c++ )); do echo -n "/x"; done)
+  length_prefix=$(for (( c=$(( ${#NIX_STORE} + ${#chunk_prefix} )) ; c < $storepath_length ; c++ )); do echo -n "x"; done)
+  out="$out$chunk_prefix$length_prefix"
+  if [ -n $chunk_prefix -o -n $length_prefix ]; then
+    mkdir -p $(dirname $out)
+  fi
+
+  : ${libc_path=}
+  : ${configureFlags=}
+  configureFlags="${configureFlags//$oldout/$out}"
+  if [ -n "$libc_path" ]; then
+    libc_oldpath=$libc_path/lib
+    libc_newpath=$(cat $libc_path/nix-support/new-out)/lib
+    configureFlags="${configureFlags//$libc_oldpath/$libc_newpath}"
+  fi
+}
+
+addNixSupport() {
+  if [ ! -d $out ]; then
+    return
+  fi
+  mkdir -p $out/nix-support
+  echo $out > $out/nix-support/new-out
+}
+
+overridePlaceholder() {
+function _callImplicitHook {
+  local def="$1"
+  local hookName="$2"
+  if declare -F "$hookName" > /dev/null; then
+      "$hookName"
+  elif type -p "$hookName" > /dev/null; then
+      source "$hookName"
+  elif [ -n "${!hookName:-}" ]; then
+      content="${!hookName}"
+      eval "${content//$oldout/$out}"
+  else
+      return "$def"
+  fi
+}
+}
+
+preHooks+=(appendOut overridePlaceholder)
+
+restoreSingleFile() {
+  if [ "$out" != "$oldout" -a -f $out ]; then
+    cp -a $out ./file
+    rm -rf $oldout
+    cp -a ./file $oldout
+  fi
+}
+
+addSymlinks() {
+  if [ "$out" != "$oldout" -a -d $out ]; then
+    ln -s $out/* $oldout/
+  fi
+}
+
+rename_generic_build() {
+eval "$(echo "orig_genericBuild()"; declare -f genericBuild | tail -n +2)"
+function genericBuild {
+  orig_genericBuild "$@"
+  restoreSingleFile
+  addSymlinks
+  addNixSupport
+}
+}
+
+exitHooks+=(restoreSingleFile addSymlinks addNixSupport)
+postHooks+=(rename_generic_build)
diff --git a/stdenv_prefix/stdenv.md b/stdenv_prefix/stdenv.md
new file mode 100644
index 0000000..f58455a
--- /dev/null
+++ b/stdenv_prefix/stdenv.md
@@ -0,0 +1,133 @@
+Ce dossier contient un travail permettant de créer des dérivations qui
+vont toutes commencer par un préfix de taille et avec un nombre de
+composants donné (de la forme x/x/xxxxx)
+
+Le but étant de pouvoir copier une closure d’une dérivation, la mettre
+par exemple dans /opt/nix/store/....-foo et avec un simple `rename` +
+`sed` la rendre utilisable (dans l’exemple /nix/store/....-foo/xxx ->
+/opt/nix/store/....-foo).
+
+Ci dessous se trouvent des notes de ce que j’ai compris de la stack
+stdenv (pkgs/stdenv/linux/default.nix)
+
+# Stage -1
+  gcc-unwrapped = null
+  binutils = null
+  coreutils = null
+  gnugrep = null
+  `stagem1 = stdenv.__bootPackages.stdenv.__bootPackages.stdenv.__bootPackages.stdenv.__bootPackages.stdenv.__bootPackages.stdenv.__bootPackages`
+  -> contient cinq entrées (dont stdenv "invalide")
+
+# Stage 0
+  `stage0 = stdenv.__bootPackages.stdenv.__bootPackages.stdenv.__bootPackages.stdenv.__bootPackages.stdenv.__bootPackages`
+  (`stagem1 = stage0.stdenv.__bootPackages`)
+  `stage0.stdenv`
+  -> cc = null
+  `stage0`
+  overrides:
+    - glibc = extrait (ln -s) de bootstrapTools (bootstrap-stage0-glibc)
+    - gcc-unwrapped = bootstrapTools
+    - binutils = wrapper sur bootstrapTools (bootstrap-stage0-binutils-wrapper)
+    - coreutils = bootstrapTools
+    - gnugrep = bootstrapTools
+    - ccWrapperStdenv = stage0.stdenv
+
+# Stage 1
+  `stage1 = stdenv.__bootPackages.stdenv.__bootPackages.stdenv.__bootPackages.stdenv.__bootPackages`
+  (`stage0 = stage1.stdenv.__bootPackages`)
+  `stage1.stdenv`
+  -> cc = cc-wrapper buildé avec
+            cc = stage0.gcc-unwrapped = bootstrapTools
+            bintools = stage0.binutils = bootstrap-stage0-binutils-wrapper
+            glibc = stage0.glibc = bootstrap-stage0-glibc
+            coreutils = stage0.coreutils = bootstrapTools
+            gnugrep = stage0.gnugrep = bootstrapTools
+            stdenvNoCC = stage0.ccWrapperStdenv = stage0.stdenv
+  `stage1`
+  overrides:
+    - binutils-unwrapped = override (gold = false)
+    - ccWrapperStdenv = stage0.stdenv
+    - gcc-unwrapped = bootstrapTools
+    - coreutils = bootstrapTools
+    - gnugrep = bootstrapTools
+    - glibc = bootstrap-stage0-glibc
+    - perl = override (threading = false)
+
+# Stage 2
+  `stage2 = stdenv.__bootPackages.stdenv.__bootPackages.stdenv.__bootPackages`
+  (`stage1 = stage2.stdenv.__bootPackages`)
+  `stage2.stdenv`
+  -> cc = cc-wrapper buildé avec
+          cc = stage1.gcc-unwrapped = bootstrapTools
+          bintools = stage1.binutils = wrapper sur binutils-unwrapped (gold = false)
+          glibc = bootstrap-stage0-glibc
+          coreutils = bootstrapTools
+          gnugrep = bootstrapTools
+          stdenvNoCC = stage1.ccWrapperStdenv = stage0.stdenv
+  `stage2`
+  overrides:
+    - ccWrapperStdenv = stage0.stdenv
+    - gcc-unwrapped = bootstrapTools
+    - coreutils = bootstrapTools
+    - gnugrep = bootstrapTools
+    - perl = override (threading = false)
+    - binutils = stage1.override (libc = self.glibc)
+    - libidn2 = nuke-refs
+    - libunistring = nuke-refs
+    - dejagnu = nocheck
+    - gnum4 = stage1.gnum4
+    - bison = stage1.bison
+
+# Stage 3
+  `stage3 = stdenv.__bootPackages.stdenv.__bootPackages`
+  (`stage2 = stage3.stdenv.__bootPackages`)
+  `stage3.stdenv`
+  -> cc = cc-wrapper buildé avec
+          cc = stage2.gcc-unwrapped = bootstrapTools
+          bintools = stage2.binutils
+          glibc = stage2.glibc
+          coreutils = bootstrapTools
+          gnugrep = bootstrapTools
+          stdenvNoCC = stage2.ccWrapperStdenv = stage0.stdenv
+  `stage3`
+  overrides:
+    - ccWrapperStdenv = stage0.stdenv
+    - binutils = stage2.binutils
+    - coreutils = bootstrapTools
+    - gnugrep = bootstrapTools
+    - perl patchelf linuxHeaders gnum4 bison libidn2 libunistring = stage2
+    - glibc = stage2.glibc
+    - gmp mpfr libmpc isl_0_20 = override static
+    - gcc-unwrapped = override (isl)
+
+# Stage 4
+  `stage4 = stdenv.__bootPackages`
+  (`stage3 = stage4.stdenv.__bootPackages`)
+  `stage4.stdenv`
+  -> cc = cc-wrapper buildé avec
+          cc = stage3.gcc-unwrapped = override (isl)
+          bintools = stage2.binutils
+          glibc = stage2.glibc
+          coreutils = bootstrapTools
+          gnugrep = bootstrapTools
+          stdenvNoCC = stage3.ccWrapperStdenv = stage0.stdenv
+  `stage4`
+  overrides:
+    - gettext gnum4 bison gmp perl texinfo zlib linuxHeaders libidn2 libunistring = stage3
+    - glibc = stage3.glibc = stage2.glibc
+    - binutils = override
+    - gcc = buildé avec
+            cc = stage3.gcc-unwrapped
+            bintools = self.binutils
+            libc = self.glibc
+            stdenvNoCC coreutils gnugrep = self
+
+# Final Stage
+  `stdenv`
+  cc = stage4.gcc
+  `pkgs`
+  overrides:
+    - glibc = stage4.glibc = stage2.glibc
+    - zlib libidn2 libunistring = stage4 = stage3
+    - (hors cross-compile) binutils binutils-unwrapped = stage4
+    - (hors cross-compile) gcc = cc