buildFHSEnv: rewrite env building

This replaces the mess of buildEnvs with a single Rust binary that
spits out a mostly-complete root filesystem for an fhsenv.

The main goal is to have includeClosures, as we want all of the
dependencies to be in the fhsenv to avoid Steam's (and others')
LD_LIBRARY_PATH shenanigans, but without 32-bit libraries leaking
into lib64 when a 64-bit package like mangohud depends on a 32-bit
version of itself.

We "fix" this by actually looking at the files and explicitly moving
32-bit stuff to $out/lib32. This could be avoided if we had recursive
Nix, or at least system info in exportReferencesGraph, but alas.

For some reason this also shrinks the fhsenvs massively, even though
there's currently no layout optimization (e.g. a package with paths
like lib/foo/{bar,baz} will produce two symlinks in the output, even
when it's more optimal to symlink lib/foo to $out/lib/foo directly).
This commit is contained in:
K900 2024-10-28 18:32:55 +03:00
parent ccac709d91
commit a182a53243
4 changed files with 678 additions and 179 deletions

View File

@ -33,18 +33,15 @@
# follows:
# /lib32 will include 32bit libraries from multiPkgs
# /lib64 will include 64bit libraries from multiPkgs and targetPkgs
# /lib will link to /lib32
# /lib will link to /lib64
let
inherit (stdenv.hostPlatform) is64bit;
name = if (args ? pname && args ? version)
then "${args.pname}-${args.version}"
else args.name;
# "use of glibc_multi is only supported on x86_64-linux"
isMultiBuild = multiArch && stdenv.system == "x86_64-linux";
isTargetBuild = !isMultiBuild;
# list of packages (usually programs) which match the host's architecture
# (which includes stuff from multiPkgs)
@ -60,7 +57,7 @@ let
baseTargetPaths = with pkgs; [
glibcLocales
(if isMultiBuild then glibc_multi else glibc)
(toString gcc.cc.lib)
gcc.cc.lib
bashInteractiveFHS
coreutils
less
@ -77,7 +74,7 @@ let
xz
];
baseMultiPaths = with pkgsi686Linux; [
(toString gcc.cc.lib)
gcc.cc.lib
];
ldconfig = writeShellScriptBin "ldconfig" ''
@ -85,190 +82,139 @@ let
exec ${if isMultiBuild then pkgsi686Linux.glibc.bin else pkgs.glibc.bin}/bin/ldconfig -f /etc/ld.so.conf -C /etc/ld.so.cache "$@"
'';
etcProfile = writeText "profile" ''
export PS1='${name}-fhsenv:\u@\h:\w\$ '
export LOCALE_ARCHIVE='/usr/lib/locale/locale-archive'
export PATH="/run/wrappers/bin:/usr/bin:/usr/sbin:$PATH"
export TZDIR='/etc/zoneinfo'
etcProfile = pkgs.writeTextFile {
name = "${name}-fhsenv-profile";
destination = "/etc/profile";
text = ''
export PS1='${name}-fhsenv:\u@\h:\w\$ '
export LOCALE_ARCHIVE='/usr/lib/locale/locale-archive'
export PATH="/run/wrappers/bin:/usr/bin:/usr/sbin:$PATH"
export TZDIR='/etc/zoneinfo'
# XDG_DATA_DIRS is used by pressure-vessel (steam proton) and vulkan loaders to find the corresponding icd
export XDG_DATA_DIRS=$XDG_DATA_DIRS''${XDG_DATA_DIRS:+:}/run/opengl-driver/share:/run/opengl-driver-32/share
# XDG_DATA_DIRS is used by pressure-vessel (steam proton) and vulkan loaders to find the corresponding icd
export XDG_DATA_DIRS=$XDG_DATA_DIRS''${XDG_DATA_DIRS:+:}/run/opengl-driver/share:/run/opengl-driver-32/share
# Following XDG spec [1], XDG_DATA_DIRS should default to "/usr/local/share:/usr/share".
# In nix, it is commonly set without containing these values, so we add them as fallback.
#
# [1] <https://specifications.freedesktop.org/basedir-spec/latest>
case ":$XDG_DATA_DIRS:" in
*:/usr/local/share:*) ;;
*) export XDG_DATA_DIRS="$XDG_DATA_DIRS''${XDG_DATA_DIRS:+:}/usr/local/share" ;;
esac
case ":$XDG_DATA_DIRS:" in
*:/usr/share:*) ;;
*) export XDG_DATA_DIRS="$XDG_DATA_DIRS''${XDG_DATA_DIRS:+:}/usr/share" ;;
esac
# Following XDG spec [1], XDG_DATA_DIRS should default to "/usr/local/share:/usr/share".
# In nix, it is commonly set without containing these values, so we add them as fallback.
#
# [1] <https://specifications.freedesktop.org/basedir-spec/latest>
case ":$XDG_DATA_DIRS:" in
*:/usr/local/share:*) ;;
*) export XDG_DATA_DIRS="$XDG_DATA_DIRS''${XDG_DATA_DIRS:+:}/usr/local/share" ;;
esac
case ":$XDG_DATA_DIRS:" in
*:/usr/share:*) ;;
*) export XDG_DATA_DIRS="$XDG_DATA_DIRS''${XDG_DATA_DIRS:+:}/usr/share" ;;
esac
# Force compilers and other tools to look in default search paths
unset NIX_ENFORCE_PURITY
export NIX_BINTOOLS_WRAPPER_TARGET_HOST_${stdenv.cc.suffixSalt}=1
export NIX_CC_WRAPPER_TARGET_HOST_${stdenv.cc.suffixSalt}=1
export NIX_CFLAGS_COMPILE='-idirafter /usr/include'
export NIX_CFLAGS_LINK='-L/usr/lib -L/usr/lib32'
export NIX_LDFLAGS='-L/usr/lib -L/usr/lib32'
export PKG_CONFIG_PATH=/usr/lib/pkgconfig
export ACLOCAL_PATH=/usr/share/aclocal
# Force compilers and other tools to look in default search paths
unset NIX_ENFORCE_PURITY
export NIX_BINTOOLS_WRAPPER_TARGET_HOST_${stdenv.cc.suffixSalt}=1
export NIX_CC_WRAPPER_TARGET_HOST_${stdenv.cc.suffixSalt}=1
export NIX_CFLAGS_COMPILE='-idirafter /usr/include'
export NIX_CFLAGS_LINK='-L/usr/lib -L/usr/lib32'
export NIX_LDFLAGS='-L/usr/lib -L/usr/lib32'
export PKG_CONFIG_PATH=/usr/lib/pkgconfig
export ACLOCAL_PATH=/usr/share/aclocal
# GStreamer searches for plugins relative to its real binary's location
# https://gitlab.freedesktop.org/gstreamer/gstreamer/-/commit/bd97973ce0f2c5495bcda5cccd4f7ef7dcb7febc
export GST_PLUGIN_SYSTEM_PATH_1_0=/usr/lib/gstreamer-1.0:/usr/lib32/gstreamer-1.0
# GStreamer searches for plugins relative to its real binary's location
# https://gitlab.freedesktop.org/gstreamer/gstreamer/-/commit/bd97973ce0f2c5495bcda5cccd4f7ef7dcb7febc
export GST_PLUGIN_SYSTEM_PATH_1_0=/usr/lib/gstreamer-1.0:/usr/lib32/gstreamer-1.0
${profile}
${profile}
'';
};
ensureGsettingsSchemasIsDirectory = runCommandLocal "fhsenv-ensure-gsettings-schemas-directory" {} ''
mkdir -p $out/share/glib-2.0/schemas
touch $out/share/glib-2.0/schemas/.keep
'';
# Compose /etc for the fhs environment
etcPkg = runCommandLocal "${name}-fhs-etc" { } ''
mkdir -p $out/etc
pushd $out/etc
# Shamelessly stolen (and cleaned up) from original buildEnv.
# Should be semantically equivalent, except we also take
# a list of default extra outputs that will be installed
# for derivations that don't explicitly specify one.
# Note that this is not the same as `extraOutputsToInstall`,
# as that will apply even to derivations with an output
# explicitly specified, so this does change the behavior
# very slightly for that particular edge case.
pickOutputs = let
pickOutputsOne = outputs: drv:
let
isSpecifiedOutput = drv.outputSpecified or false;
outputsToInstall = drv.meta.outputsToInstall or null;
pickedOutputs = if isSpecifiedOutput || outputsToInstall == null
then [ drv ]
else map (out: drv.${out} or null) (outputsToInstall ++ outputs);
extraOutputs = map (out: drv.${out} or null) extraOutputsToInstall;
cleanOutputs = lib.filter (o: o != null) (pickedOutputs ++ extraOutputs);
in {
paths = cleanOutputs;
priority = drv.meta.priority or lib.meta.defaultPriority;
};
in paths: outputs: map (pickOutputsOne outputs) paths;
# environment variables
ln -s ${etcProfile} profile
paths = let
basePaths = [
etcProfile
# ldconfig wrapper must come first so it overrides the original ldconfig
ldconfig
# magic package that just creates a directory, to ensure that
# the entire directory can't be a symlink, as we will write
# compiled schemas to it
ensureGsettingsSchemasIsDirectory
] ++ baseTargetPaths ++ targetPaths;
in pickOutputs basePaths ["out" "lib" "bin"];
paths32 = lib.optionals isMultiBuild (
let
basePaths = baseMultiPaths ++ multiPaths;
in pickOutputs basePaths ["out" "lib"]
);
allPaths = paths ++ paths32;
rootfs-builder = pkgs.rustPlatform.buildRustPackage {
name = "fhs-rootfs-bulder";
src = ./rootfs-builder;
cargoLock.lockFile = ./rootfs-builder/Cargo.lock;
doCheck = false;
};
rootfs = pkgs.runCommand "${name}-fhsenv-rootfs" {
__structuredAttrs = true;
exportReferencesGraph.graph = lib.concatMap (p: p.paths) allPaths;
inherit paths paths32 isMultiBuild includeClosures;
nativeBuildInputs = [ pkgs.jq ];
} ''
${rootfs-builder}/bin/rootfs-builder
# create a bunch of symlinks for usrmerge
ln -s /usr/bin $out/bin
ln -s /usr/sbin $out/sbin
ln -s /usr/lib $out/lib
ln -s /usr/lib32 $out/lib32
ln -s /usr/lib64 $out/lib64
ln -s /usr/lib64 $out/usr/lib
# symlink 32-bit ld-linux so it's visible in /lib
if [ -e $out/usr/lib32/ld-linux.so.2 ]; then
ln -s /usr/lib32/ld-linux.so.2 $out/usr/lib64/ld-linux.so.2
fi
# symlink /etc/mtab -> /proc/mounts (compat for old userspace progs)
ln -s /proc/mounts mtab
'';
ln -s /proc/mounts $out/etc/mtab
# Composes a /usr-like directory structure
staticUsrProfileTarget = buildEnv {
name = "${name}-usr-target";
# ldconfig wrapper must come first so it overrides the original ldconfig
paths = [ etcPkg ldconfig ] ++ baseTargetPaths ++ targetPaths;
extraOutputsToInstall = [ "out" "lib" "bin" ] ++ extraOutputsToInstall;
ignoreCollisions = true;
postBuild = ''
if [[ -d $out/share/gsettings-schemas/ ]]; then
# Recreate the standard schemas directory if its a symlink to make it writable
if [[ -L $out/share/glib-2.0 ]]; then
target=$(readlink $out/share/glib-2.0)
rm $out/share/glib-2.0
mkdir $out/share/glib-2.0
ln -fsr $target/* $out/share/glib-2.0
fi
if [[ -L $out/share/glib-2.0/schemas ]]; then
target=$(readlink $out/share/glib-2.0/schemas)
rm $out/share/glib-2.0/schemas
mkdir $out/share/glib-2.0/schemas
ln -fsr $target/* $out/share/glib-2.0/schemas
fi
mkdir -p $out/share/glib-2.0/schemas
for d in $out/share/gsettings-schemas/*; do
# Force symlink, in case there are duplicates
ln -fsr $d/glib-2.0/schemas/*.xml $out/share/glib-2.0/schemas
ln -fsr $d/glib-2.0/schemas/*.gschema.override $out/share/glib-2.0/schemas
done
# and compile them
${pkgs.glib.dev}/bin/glib-compile-schemas $out/share/glib-2.0/schemas
fi
'';
inherit includeClosures;
};
staticUsrProfileMulti = buildEnv {
name = "${name}-usr-multi";
paths = baseMultiPaths ++ multiPaths;
extraOutputsToInstall = [ "out" "lib" ] ++ extraOutputsToInstall;
ignoreCollisions = true;
inherit includeClosures;
};
# setup library paths only for the targeted architecture
setupLibDirsTarget = ''
# link content of targetPaths
cp -rsHf ${staticUsrProfileTarget}/lib lib
ln -s lib lib${if is64bit then "64" else "32"}
'';
# setup /lib, /lib32 and /lib64
setupLibDirsMulti = ''
mkdir -m0755 lib32
mkdir -m0755 lib64
ln -s lib64 lib
# copy glibc stuff
cp -rsHf ${staticUsrProfileTarget}/lib/32/* lib32/
chmod u+w -R lib32/
# copy content of multiPaths (32bit libs)
if [ -d ${staticUsrProfileMulti}/lib ]; then
cp -rsHf ${staticUsrProfileMulti}/lib/* lib32/
chmod u+w -R lib32/
if [[ -d $out/usr/share/gsettings-schemas/ ]]; then
for d in $out/usr/share/gsettings-schemas/*; do
# Force symlink, in case there are duplicates
ln -fsr $d/glib-2.0/schemas/*.xml $out/usr/share/glib-2.0/schemas
ln -fsr $d/glib-2.0/schemas/*.gschema.override $out/usr/share/glib-2.0/schemas
done
${pkgs.glib.dev}/bin/glib-compile-schemas $out/usr/share/glib-2.0/schemas
fi
# copy content of targetPaths (64bit libs)
cp -rsHf ${staticUsrProfileTarget}/lib/* lib64/
chmod u+w -R lib64/
# symlink 32-bit ld-linux.so
ln -Lsf ${staticUsrProfileTarget}/lib/32/ld-linux.so.2 lib/
${extraBuildCommands}
${lib.optionalString isMultiBuild extraBuildCommandsMulti}
'';
setupLibDirs = if isTargetBuild
then setupLibDirsTarget
else setupLibDirsMulti;
# the target profile is the actual profile that will be used for the fhs
setupTargetProfile = ''
mkdir -m0755 usr
pushd usr
${setupLibDirs}
'' + lib.optionalString isMultiBuild ''
if [ -d "${staticUsrProfileMulti}/share" ]; then
cp -rLf ${staticUsrProfileMulti}/share share
fi
'' + ''
if [ -d "${staticUsrProfileTarget}/share" ]; then
if [ -d share ]; then
chmod -R 755 share
cp -rLTf ${staticUsrProfileTarget}/share share
else
cp -rsHf ${staticUsrProfileTarget}/share share
fi
fi
for i in bin sbin include; do
if [ -d "${staticUsrProfileTarget}/$i" ]; then
cp -rsHf "${staticUsrProfileTarget}/$i" "$i"
fi
done
cd ..
for i in etc opt; do
if [ -d "${staticUsrProfileTarget}/$i" ]; then
cp -rsHf "${staticUsrProfileTarget}/$i" "$i"
fi
done
for i in usr/{bin,sbin,lib,lib32,lib64}; do
if [ -d "$i" ]; then
ln -s "$i"
fi
done
popd
'';
in runCommandLocal "${name}-fhs" {
inherit nativeBuildInputs;
passthru = {
inherit args baseTargetPaths targetPaths baseMultiPaths ldconfig isMultiBuild;
};
} ''
mkdir -p $out
pushd $out
${setupTargetProfile}
${extraBuildCommands}
${lib.optionalString isMultiBuild extraBuildCommandsMulti}
''
in rootfs

View File

@ -0,0 +1,249 @@
# This file is automatically @generated by Cargo.
# It is not intended for manual editing.
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View File

@ -0,0 +1,11 @@
[package]
name = "rootfs-builder"
version = "0.1.0"
edition = "2021"
[dependencies]
anyhow = "*"
serde = { version = "*", features = ["derive"] }
serde_json = "*"
walkdir = "*"
goblin = "*"

View File

@ -0,0 +1,293 @@
#![deny(clippy::pedantic)]
use std::{
collections::{hash_map::Entry, HashMap},
env,
fs::{self, File},
io::{BufReader, Read},
os::unix::fs as ufs,
path::{Path, PathBuf},
};
use anyhow::{anyhow, Context};
use goblin::{Hint, Object};
use serde::Deserialize;
use walkdir::WalkDir;
#[derive(Debug, Deserialize)]
struct RefGraphNode {
path: PathBuf,
references: Vec<PathBuf>,
}
#[derive(Debug, Deserialize)]
struct InputDrv {
paths: Vec<PathBuf>,
priority: i64,
}
#[derive(Debug, Deserialize)]
#[serde(rename_all = "camelCase")]
struct StructuredAttrsRoot {
graph: Vec<RefGraphNode>,
paths: Vec<InputDrv>,
paths32: Vec<InputDrv>,
include_closures: bool,
}
#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
struct PriorityKey {
implicit: bool,
group_priority: i64,
priority: i64,
root_index: usize,
}
fn build_reference_map(refs: Vec<RefGraphNode>) -> HashMap<PathBuf, Vec<PathBuf>> {
refs.into_iter()
.map(|mut gn| {
gn.references.retain_mut(|x| x != &gn.path);
(gn.path, gn.references)
})
.collect()
}
fn build_priority_keys(roots: &[InputDrv], group_priority: i64) -> HashMap<PathBuf, PriorityKey> {
let mut roots_map = HashMap::new();
for (idx, path) in roots.iter().enumerate() {
for subpath in &path.paths {
let priority = PriorityKey {
group_priority,
priority: path.priority,
root_index: idx,
implicit: false,
};
roots_map.entry(subpath.clone()).or_insert(priority);
}
}
roots_map
}
fn extend_to_closure(
roots: HashMap<PathBuf, PriorityKey>,
refs: &HashMap<PathBuf, Vec<PathBuf>>,
) -> anyhow::Result<HashMap<PathBuf, PriorityKey>> {
let mut path_map = HashMap::new();
for (root, priority) in roots {
path_map.insert(root.clone(), priority);
let mut priority = priority;
priority.implicit = true;
let mut stack = vec![root.clone()];
while let Some(next) = stack.pop() {
match path_map.entry(next.clone()) {
Entry::Occupied(mut occupied_entry) => {
let old_priority: &PriorityKey = occupied_entry.get();
if old_priority > &priority {
occupied_entry.insert(priority);
}
}
Entry::Vacant(vacant_entry) => {
vacant_entry.insert(priority);
}
}
stack.extend_from_slice(refs.get(&next).ok_or(anyhow!("encountered unknown path"))?);
}
}
Ok(path_map)
}
#[derive(Clone, Debug)]
struct CandidatePath {
root: PathBuf,
relative: PathBuf,
priority: PriorityKey,
}
fn collect_candidate_paths(
paths: HashMap<PathBuf, PriorityKey>,
mapper: impl Fn(&Path, &Path) -> Option<PathBuf>,
) -> anyhow::Result<HashMap<PathBuf, Vec<CandidatePath>>> {
let mut candidates: HashMap<_, Vec<_>> = HashMap::new();
for (path, priority) in paths {
for entry in WalkDir::new(&path).follow_links(true) {
let entry: PathBuf = match entry {
Ok(ent) => {
// we don't care about directory structure
if ent.file_type().is_dir() {
continue;
}
ent.path().into()
}
Err(e) => {
match e.io_error() {
// could be a broken symlink, that's fine, we still want to handle those
Some(_) => e
.path()
.ok_or_else(|| anyhow!("I/O error when walking {path:?}"))?
.into(),
None => {
// symlink loop
continue;
}
}
}
};
let relative = entry.strip_prefix(&path)?.to_owned();
if let Some(mapped) = mapper(&path, &relative) {
candidates.entry(mapped).or_default().push(CandidatePath {
root: path.clone(),
relative,
priority,
});
}
}
}
Ok(candidates)
}
fn remap_native_path(root: &Path, p: &Path) -> Option<PathBuf> {
if p.starts_with("bin/") || p.starts_with("sbin/") {
return Some(PathBuf::from("usr/").join(p));
}
// glibc-multilib special case
if let Ok(no_lib32) = p.strip_prefix("lib/32/") {
return Some(PathBuf::from("usr/lib32/").join(no_lib32));
}
remap_multilib_path(root, p)
}
fn is_32_bit(path: &Path) -> bool {
// Be as pessimistic as possible, at least for now.
let Ok(mut f) = File::open(path) else {
return false;
};
let Ok(Hint::Elf(hint)) = goblin::peek(&mut f) else {
return false;
};
if let Some(is64) = hint.is_64 {
return !is64;
}
let mut buf = vec![];
let Ok(_) = f.read_to_end(&mut buf) else {
return false;
};
let Ok(Object::Elf(e)) = goblin::Object::parse(&buf) else {
return false;
};
!e.is_64
}
fn remap_multilib_path(root: &Path, p: &Path) -> Option<PathBuf> {
if let Ok(no_lib) = p.strip_prefix("lib/") {
let full = root.join(p);
let libdir = if is_32_bit(&full) { "lib32" } else { "lib64" };
return Some(PathBuf::from("usr/").join(libdir).join(no_lib));
}
if p.starts_with("etc/") || p.starts_with("opt/") {
return Some(p.into());
}
if p.starts_with("share/") || p.starts_with("include/") {
return Some(PathBuf::from("usr/").join(p));
}
None
}
fn build_plan(
paths: HashMap<PathBuf, PriorityKey>,
paths32: HashMap<PathBuf, PriorityKey>,
) -> anyhow::Result<HashMap<PathBuf, PathBuf>> {
let candidates_native = collect_candidate_paths(paths, remap_native_path)?;
let candidates_32 = collect_candidate_paths(paths32, remap_multilib_path)?;
let mut all_candidates: HashMap<_, Vec<_>> = HashMap::new();
for map in [candidates_native, candidates_32] {
for (path, candidates) in map {
all_candidates
.entry(path)
.or_default()
.extend_from_slice(&candidates);
}
}
let mut final_plan: HashMap<PathBuf, PathBuf> = HashMap::new();
for (path, candidates) in all_candidates {
let best = candidates
.into_iter()
.min_by_key(|&CandidatePath { priority, .. }| priority)
.ok_or(anyhow!("candidate list empty"))?;
final_plan.insert(path, best.root.join(best.relative));
}
Ok(final_plan)
}
fn build_env(out: &Path, plan: HashMap<PathBuf, PathBuf>) -> anyhow::Result<()> {
fs::create_dir_all(out)?;
for (dest, src) in plan {
let full_dest = out.join(&dest);
let dest_dir = full_dest
.parent()
.ok_or(anyhow!("destination directory is root"))
.with_context(|| {
format!("When trying to determine destination directory for {full_dest:?}")
})?;
fs::create_dir_all(dest_dir)
.with_context(|| format!("When trying to create directory {dest_dir:?}"))?;
ufs::symlink(&src, &full_dest)
.with_context(|| format!("When symlinking {src:?} to {full_dest:?}"))?;
}
Ok(())
}
fn main() -> anyhow::Result<()> {
let filename = env::var("NIX_ATTRS_JSON_FILE")?;
let reader = File::open(filename)?;
let buf_reader = BufReader::new(reader);
let attrs: StructuredAttrsRoot = serde_json::from_reader(buf_reader)?;
let mut paths = build_priority_keys(&attrs.paths, 1);
let mut paths32 = build_priority_keys(&attrs.paths32, 2);
if attrs.include_closures {
let refs = build_reference_map(attrs.graph);
paths = extend_to_closure(paths, &refs)?;
paths32 = extend_to_closure(paths32, &refs)?;
};
let plan = build_plan(paths, paths32)?;
let out_dir = env::var("out")?;
build_env(&PathBuf::from(out_dir), plan)
}