core/pkgs/build-support/bintools-wrapper/default.nix

# The Nixpkgs CC is not directly usable, since it doesn't know where
# the C library and standard header files are. Therefore the compiler
# produced by that package cannot be installed directly in a user
# environment and used from the command line. So we use a wrapper
# script that sets up the right environment variables so that the
# compiler and the linker just "work".

{ name ? "", lib, stdenvNoCC, runtimeShell, bintools ? null, libc ? null
, coreutils ? null, gnugrep ? null, netbsd ? null, netbsdCross ? null
, sharedLibraryLoader ? if libc == null then
  null
else if stdenvNoCC.targetPlatform.isNetBSD then
  if !(targetPackages ? netbsdCross) then
    netbsd.ld_elf_so
  else if libc != targetPackages.netbsdCross.headers then
    targetPackages.netbsdCross.ld_elf_so
  else
    null
else
  lib.getLib libc, nativeTools, noLibc ? false, nativeLibc, nativePrefix ? ""
, propagateDoc ? bintools != null && bintools ? man, extraPackages ? [ ]
, extraBuildCommands ? "", isGNU ? bintools.isGNU or false
, isLLVM ? bintools.isLLVM or false, isCCTools ? bintools.isCCTools or false
, expand-response-params, targetPackages ? { }, useMacosReexportHack ? false
, wrapGas ? false

  # Note: the hardening flags are part of the bintools-wrapper, rather than
  # the cc-wrapper, because a few of them are handled by the linker.
, defaultHardeningFlags ? [
  "bindnow"
  "format"
  "fortify"
  "fortify3"
  "pic"
  "relro"
  "stackprotector"
  "strictoverflow"
] ++ lib.optional (with stdenvNoCC;
# Musl-based platforms will keep "pie", other platforms will not.
# If you change this, make sure to update section `{#sec-hardening-in-nixpkgs}`
# in the nixpkgs manual to inform users about the defaults.
  targetPlatform.libc == "musl"
  # Except when:
  #    - static aarch64, where compilation works, but produces segfaulting dynamically linked binaries.
  #    - static armv7l, where compilation fails.
  && !(targetPlatform.isAarch && targetPlatform.isStatic)) "pie"

  # Darwin code signing support utilities
, postLinkSignHook ? null, signingUtils ? null }:

assert nativeTools -> !propagateDoc && nativePrefix != "";
assert !nativeTools -> bintools != null && coreutils != null && gnugrep != null;
assert !(nativeLibc && noLibc);
assert (noLibc || nativeLibc) == (libc == null);

let
  inherit (lib)
    attrByPath concatStringsSep getBin getDev getLib getName getVersion
    hasSuffix optional optionalAttrs optionals optionalString platforms
    removePrefix replaceStrings;

  inherit (stdenvNoCC) hostPlatform targetPlatform;

  # Prefix for binaries. Customarily ends with a dash separator.
  #
  # TODO(@Ericson2314) Make unconditional, or optional but always true by
  # default.
  targetPrefix = optionalString (targetPlatform != hostPlatform)
    (targetPlatform.config + "-");

  bintoolsVersion = getVersion bintools;
  bintoolsName = removePrefix targetPrefix (getName bintools);

  libc_bin = optionalString (libc != null) (getBin libc);
  libc_dev = optionalString (libc != null) (getDev libc);
  libc_lib = optionalString (libc != null) (getLib libc);
  bintools_bin = optionalString (!nativeTools) (getBin bintools);
  # The wrapper scripts use 'cat' and 'grep', so we may need coreutils.
  coreutils_bin = optionalString (!nativeTools) (getBin coreutils);

  # See description in cc-wrapper.
  suffixSalt = replaceStrings [ "-" "." ] [ "_" "_" ] targetPlatform.config;

  # The dynamic linker has different names on different platforms. This is a
  # shell glob that ought to match it.
  dynamicLinker = if sharedLibraryLoader == null then
    ""
  else if targetPlatform.libc == "musl" then
    "${sharedLibraryLoader}/lib/ld-musl-*"
  else if targetPlatform.libc == "uclibc" then
    "${sharedLibraryLoader}/lib/ld*-uClibc.so.1"
  else if (targetPlatform.libc == "bionic" && targetPlatform.is32bit) then
    "/system/bin/linker"
  else if (targetPlatform.libc == "bionic" && targetPlatform.is64bit) then
    "/system/bin/linker64"
  else if targetPlatform.libc == "nblibc" then
    "${sharedLibraryLoader}/libexec/ld.elf_so"
  else if targetPlatform.system == "i686-linux" then
    "${sharedLibraryLoader}/lib/ld-linux.so.2"
  else if targetPlatform.system == "x86_64-linux" then
    "${sharedLibraryLoader}/lib/ld-linux-x86-64.so.2"
    # ELFv1 (.1) or ELFv2 (.2) ABI
  else if targetPlatform.isPower64 then
    "${sharedLibraryLoader}/lib/ld64.so.*"
    # ARM with a wildcard, which can be "" or "-armhf".
  else if (with targetPlatform; isAarch32 && isLinux) then
    "${sharedLibraryLoader}/lib/ld-linux*.so.3"
  else if targetPlatform.system == "aarch64-linux" then
    "${sharedLibraryLoader}/lib/ld-linux-aarch64.so.1"
  else if targetPlatform.system == "powerpc-linux" then
    "${sharedLibraryLoader}/lib/ld.so.1"
  else if targetPlatform.isMips then
    "${sharedLibraryLoader}/lib/ld.so.1"
    # `ld-linux-riscv{32,64}-<abi>.so.1`
  else if targetPlatform.isRiscV then
    "${sharedLibraryLoader}/lib/ld-linux-riscv*.so.1"
  else if targetPlatform.isLoongArch64 then
    "${sharedLibraryLoader}/lib/ld-linux-loongarch*.so.1"
  else if targetPlatform.isDarwin then
    "/usr/lib/dyld"
  else if targetPlatform.isFreeBSD then
    "/libexec/ld-elf.so.1"
  else if hasSuffix "pc-gnu" targetPlatform.config then
    "ld.so.1"
  else
    "";

in stdenvNoCC.mkDerivation {
  pname = targetPrefix
    + (if name != "" then name else "${bintoolsName}-wrapper");
  version = optionalString (bintools != null) bintoolsVersion;

  preferLocalBuild = true;

  outputs = [ "out" ]
    ++ optionals propagateDoc ([ "man" ] ++ optional (bintools ? info) "info");

  passthru = {
    inherit targetPrefix suffixSalt;
    inherit bintools libc nativeTools nativeLibc nativePrefix isGNU isLLVM;

    emacsBufferSetup = pkgs: ''
      ; We should handle propagation here too
      (mapc
        (lambda (arg)
          (when (file-directory-p (concat arg "/lib"))
            (setenv "NIX_LDFLAGS_${suffixSalt}" (concat (getenv "NIX_LDFLAGS_${suffixSalt}") " -L" arg "/lib")))
          (when (file-directory-p (concat arg "/lib64"))
            (setenv "NIX_LDFLAGS_${suffixSalt}" (concat (getenv "NIX_LDFLAGS_${suffixSalt}") " -L" arg "/lib64"))))
        '(${concatStringsSep " " (map (pkg: ''"${pkg}"'') pkgs)}))
    '';

    inherit defaultHardeningFlags;
  };

  dontBuild = true;
  dontConfigure = true;

  enableParallelBuilding = true;

  unpackPhase = ''
    src=$PWD
  '';

  installPhase = ''
    mkdir -p $out/bin $out/nix-support

    wrap() {
      local dst="$1"
      local wrapper="$2"
      export prog="$3"
      export use_response_file_by_default=${if isCCTools then "1" else "0"}
      substituteAll "$wrapper" "$out/bin/$dst"
      chmod +x "$out/bin/$dst"
    }
  ''

    + (if nativeTools then ''
      echo ${nativePrefix} > $out/nix-support/orig-bintools

      ldPath="${nativePrefix}/bin"
    '' else
      ''
        echo $bintools_bin > $out/nix-support/orig-bintools

        ldPath="${bintools_bin}/bin"
      ''

      # Solaris needs an additional ld wrapper.
      + optionalString (targetPlatform.isSunOS && nativePrefix != "") ''
        ldPath="${nativePrefix}/bin"
        exec="$ldPath/${targetPrefix}ld"
        wrap ld-solaris ${./ld-solaris-wrapper.sh}
      '')

    # If we are asked to wrap `gas` and this bintools has it,
    # then symlink it (`as` will be symlinked next).
    # This is mainly for the wrapped gnat-bootstrap on x86-64 Darwin,
    # as it must have both the GNU assembler from cctools (installed as `gas`)
    # and the Clang integrated assembler (installed as `as`).
    # See pkgs/os-specific/darwin/binutils/default.nix for details.
    + optionalString wrapGas ''
      if [ -e $ldPath/${targetPrefix}gas ]; then
        ln -s $ldPath/${targetPrefix}gas $out/bin/${targetPrefix}gas
      fi
    ''

    # Create symlinks for rest of the binaries.
    + ''
      for binary in objdump objcopy size strings as ar nm gprof dwp c++filt addr2line \
          ranlib readelf elfedit dlltool dllwrap windmc windres; do
        if [ -e $ldPath/${targetPrefix}''${binary} ]; then
          ln -s $ldPath/${targetPrefix}''${binary} $out/bin/${targetPrefix}''${binary}
        fi
      done

    '' + (if !useMacosReexportHack then ''
      if [ -e ''${ld:-$ldPath/${targetPrefix}ld} ]; then
        wrap ${targetPrefix}ld ${
          ./ld-wrapper.sh
        } ''${ld:-$ldPath/${targetPrefix}ld}
      fi
    '' else ''
      ldInner="${targetPrefix}ld-reexport-delegate"
      wrap "$ldInner" ${
        ./macos-sierra-reexport-hack.bash
      } ''${ld:-$ldPath/${targetPrefix}ld}
      wrap "${targetPrefix}ld" ${./ld-wrapper.sh} "$out/bin/$ldInner"
      unset ldInner
    '') + ''

      for variant in $ldPath/${targetPrefix}ld.*; do
        basename=$(basename "$variant")
        wrap $basename ${./ld-wrapper.sh} $variant
      done
    '';

  strictDeps = true;
  depsTargetTargetPropagated = extraPackages;

  setupHooks = [ ../setup-hooks/role.bash ./setup-hook.sh ];

  postFixup =
    ##
    ## General libc support
    ##
    optionalString (libc != null) (''
      touch "$out/nix-support/libc-ldflags"
      echo "-L${libc_lib}${
        libc.libdir or "/lib"
      }" >> $out/nix-support/libc-ldflags

      echo "${libc_lib}" > $out/nix-support/orig-libc
      echo "${libc_dev}" > $out/nix-support/orig-libc-dev
    ''

      ##
      ## Dynamic linker support
      ##
      + optionalString (sharedLibraryLoader != null) ''
        if [[ -z ''${dynamicLinker+x} ]]; then
          echo "Don't know the name of the dynamic linker for platform '${targetPlatform.config}', so guessing instead." >&2
          local dynamicLinker="${sharedLibraryLoader}/lib/ld*.so.?"
        fi
      ''

      # Expand globs to fill array of options
      + ''
        dynamicLinker=($dynamicLinker)

        case ''${#dynamicLinker[@]} in
          0) echo "No dynamic linker found for platform '${targetPlatform.config}'." >&2;;
          1) echo "Using dynamic linker: '$dynamicLinker'" >&2;;
          *) echo "Multiple dynamic linkers found for platform '${targetPlatform.config}'." >&2;;
        esac

        if [ -n "''${dynamicLinker-}" ]; then
          echo $dynamicLinker > $out/nix-support/dynamic-linker

          ${
            if targetPlatform.isDarwin then ''
              printf "export LD_DYLD_PATH=%q\n" "$dynamicLinker" >> $out/nix-support/setup-hook
            '' else
              optionalString (sharedLibraryLoader != null) ''
                if [ -e ${sharedLibraryLoader}/lib/32/ld-linux.so.2 ]; then
                  echo ${sharedLibraryLoader}/lib/32/ld-linux.so.2 > $out/nix-support/dynamic-linker-m32
                fi
                touch $out/nix-support/ld-set-dynamic-linker
              ''
          }
        fi
      '')

    ##
    ## User env support
    ##

    # Propagate the underling unwrapped bintools so that if you
    # install the wrapper, you get tools like objdump (same for any
    # binaries of libc).
    + optionalString (!nativeTools) ''
      printWords ${bintools_bin} ${
        optionalString (libc != null) libc_bin
      } > $out/nix-support/propagated-user-env-packages
    ''

    ##
    ## Man page and info support
    ##
    + optionalString propagateDoc (''
      ln -s ${bintools.man} $man
    '' + optionalString (bintools ? info) ''
      ln -s ${bintools.info} $info
    '')

    ##
    ## Hardening support
    ##

    # some linkers on some platforms don't support specific -z flags
    + ''
      export hardening_unsupported_flags=""
      if [[ "$($ldPath/${targetPrefix}ld -z now 2>&1 || true)" =~ un(recognized|known)\ option ]]; then
        hardening_unsupported_flags+=" bindnow"
      fi
      if [[ "$($ldPath/${targetPrefix}ld -z relro 2>&1 || true)" =~ un(recognized|known)\ option ]]; then
        hardening_unsupported_flags+=" relro"
      fi
    ''

    + optionalString hostPlatform.isCygwin ''
      hardening_unsupported_flags+=" pic"
    ''

    + optionalString (targetPlatform.isAvr || targetPlatform.isWindows) ''
      hardening_unsupported_flags+=" relro bindnow"
    ''

    + optionalString (libc != null && targetPlatform.isAvr) ''
      for isa in avr5 avr3 avr4 avr6 avr25 avr31 avr35 avr51 avrxmega2 avrxmega4 avrxmega5 avrxmega6 avrxmega7 tiny-stack; do
        echo "-L${getLib libc}/avr/lib/$isa" >> $out/nix-support/libc-cflags
      done
    ''

    + optionalString targetPlatform.isDarwin ''
      echo "-arch ${targetPlatform.darwinArch}" >> $out/nix-support/libc-ldflags
    ''

    ##
    ## GNU specific extra strip flags
    ##

    # TODO(@sternenseemann): make a generic strip wrapper?
    + optionalString (bintools.isGNU or false) ''
      wrap ${targetPrefix}strip ${./gnu-binutils-strip-wrapper.sh} \
        "${bintools_bin}/bin/${targetPrefix}strip"
    ''

    ###
    ### Remove certain timestamps from final binaries
    ###
    + optionalString (targetPlatform.isDarwin && !(bintools.isGNU or false)) ''
      echo "export ZERO_AR_DATE=1" >> $out/nix-support/setup-hook
    ''

    + ''
      for flags in "$out/nix-support"/*flags*; do
        substituteInPlace "$flags" --replace $'\n' ' '
      done

      substituteAll ${./add-flags.sh} $out/nix-support/add-flags.sh
      substituteAll ${./add-hardening.sh} $out/nix-support/add-hardening.sh
      substituteAll ${../wrapper-common/utils.bash} $out/nix-support/utils.bash
    ''

    ###
    ### Ensure consistent LC_VERSION_MIN_MACOSX
    ###
    + optionalString targetPlatform.isDarwin (let
      inherit (targetPlatform)
        darwinPlatform darwinSdkVersion darwinMinVersion
        darwinMinVersionVariable;
    in ''
      export darwinPlatform=${darwinPlatform}
      export darwinMinVersion=${darwinMinVersion}
      export darwinSdkVersion=${darwinSdkVersion}
      export darwinMinVersionVariable=${darwinMinVersionVariable}
      substituteAll ${
        ./add-darwin-ldflags-before.sh
      } $out/nix-support/add-local-ldflags-before.sh
    '')

    ##
    ## Code signing on Apple Silicon
    ##
    + optionalString (targetPlatform.isDarwin && targetPlatform.isAarch64) ''
      echo 'source ${postLinkSignHook}' >> $out/nix-support/post-link-hook

      export signingUtils=${signingUtils}

      wrap \
        ${targetPrefix}install_name_tool \
        ${./darwin-install_name_tool-wrapper.sh} \
        "${bintools_bin}/bin/${targetPrefix}install_name_tool"

      wrap \
        ${targetPrefix}strip ${./darwin-strip-wrapper.sh} \
        "${bintools_bin}/bin/${targetPrefix}strip"
    ''

    ##
    ## Extra custom steps
    ##
    + extraBuildCommands;

  env = {
    # for substitution in utils.bash
    # TODO(@sternenseemann): invent something cleaner than passing in "" in case of absence
    expandResponseParams =
      "${expand-response-params}/bin/expand-response-params";
    # TODO(@sternenseemann): rename env var via stdenv rebuild
    shell = (getBin runtimeShell + runtimeShell.shellPath or "");
    gnugrep_bin = optionalString (!nativeTools) gnugrep;
    wrapperName = "BINTOOLS_WRAPPER";
    inherit dynamicLinker targetPrefix suffixSalt coreutils_bin;
    inherit bintools_bin libc_bin libc_dev libc_lib;
    default_hardening_flags_str = builtins.toString defaultHardeningFlags;
  };

  meta = let bintools_ = optionalAttrs (bintools != null) bintools;
  in (optionalAttrs (bintools_ ? meta)
    (removeAttrs bintools.meta [ "priority" ])) // {
      description =
        attrByPath [ "meta" "description" ] "System binary utilities" bintools_
        + " (wrapper script)";
      priority = 10;
    } // optionalAttrs useMacosReexportHack { platforms = platforms.darwin; };
}