Merge pull request #124556 from bergkvist/bergkvist/make-c-wrapper

Generate tiny compiled binary for wrapping executables

doc/stdenv/stdenv.chapter.md

@@ -796,7 +796,7 @@ The standard environment provides a number of useful functions.
 
 ### `makeWrapper` \<executable\> \<wrapperfile\> \<args\> {#fun-makeWrapper}
 
-Constructs a wrapper for a program with various possible arguments. For example:
+Constructs a wrapper for a program with various possible arguments. It is defined as part of 2 setup-hooks named `makeWrapper` and `makeBinaryWrapper` that implement the same bash functions. Hence, to use it you have to add `makeWrapper` to your `nativeBuildInputs`. Here's an example usage:
 
 ```bash
 # adds `FOOBAR=baz` to `$out/bin/foo`’s environment
@@ -808,9 +808,11 @@ makeWrapper $out/bin/foo $wrapperfile --set FOOBAR baz
 makeWrapper $out/bin/foo $wrapperfile --prefix PATH : ${lib.makeBinPath [ hello git ]}
 ```
 
-There’s many more kinds of arguments, they are documented in `nixpkgs/pkgs/build-support/setup-hooks/make-wrapper.sh`.
+There’s many more kinds of arguments, they are documented in `nixpkgs/pkgs/build-support/setup-hooks/make-wrapper.sh` for the `makeWrapper` implementation and in `nixpkgs/pkgs/build-support/setup-hooks/make-binary-wrapper.sh` for the `makeBinaryWrapper` implementation.
 
-`wrapProgram` is a convenience function you probably want to use most of the time.
+`wrapProgram` is a convenience function you probably want to use most of the time, implemented by both `makeWrapper` and `makeBinaryWrapper`.
+
+Using the `makeBinaryWrapper` implementation is usually preferred, as it creates a tiny _compiled_ wrapper executable, that can be used as a shebang interpreter. This is needed mostly on Darwin, where shebangs cannot point to scripts, [due to a limitation with the `execve`-syscall](https://stackoverflow.com/questions/67100831/macos-shebang-with-absolute-path-not-working). Compiled wrappers generated by `makeBinaryWrapper` can be inspected with `less <path-to-wrapper>` - by scrolling past the binary data you should be able to see the shell command that generated the executable and there see the environment variables that were injected into the wrapper.
 
 ### `substitute` \<infile\> \<outfile\> \<subs\> {#fun-substitute}
 
@@ -885,9 +887,9 @@ someVar=$(stripHash $name)
 
 ### `wrapProgram` \<executable\> \<makeWrapperArgs\> {#fun-wrapProgram}
 
-Convenience function for `makeWrapper` that automatically creates a sane wrapper file. It takes all the same arguments as `makeWrapper`, except for `--argv0`.
+Convenience function for `makeWrapper` that replaces `<\executable\>` with a wrapper that executes the original program. It takes all the same arguments as `makeWrapper`, except for `--inherit-argv0` (used by the `makeBinaryWrapper` implementation) and `--argv0` (used by both `makeWrapper` and `makeBinaryWrapper` wrapper implementations).
 
-It cannot be applied multiple times, since it will overwrite the wrapper file.
+If you will apply it multiple times, it will overwrite the wrapper file and you will end up with double wrapping, which should be avoided.
 
 ## Package setup hooks {#ssec-setup-hooks}
 

maintainers/maintainer-list.nix

@@ -1414,6 +1414,12 @@
     githubId = 251106;
     name = "Daniel Bergey";
   };
+  bergkvist = {
+    email = "tobias@bergkv.ist";
+    github = "bergkvist";
+    githubId = 410028;
+    name = "Tobias Bergkvist";
+  };
   betaboon = {
     email = "betaboon@0x80.ninja";
     github = "betaboon";

pkgs/build-support/setup-hooks/make-binary-wrapper.sh

@@ -0,0 +1,384 @@
+
+set -euo pipefail
+
+# Assert that FILE exists and is executable
+#
+# assertExecutable FILE
+assertExecutable() {
+    local file="$1"
+    [[ -f "$file" && -x "$file" ]] || \
+        die "Cannot wrap '$file' because it is not an executable file"
+}
+
+# Generate a binary executable wrapper for wrapping an executable.
+# The binary is compiled from generated C-code using gcc.
+# makeWrapper EXECUTABLE OUT_PATH ARGS
+
+# ARGS:
+# --argv0       NAME    : set name of executed process to NAME
+#                         (otherwise it’s called …-wrapped)
+# --inherit-argv0       : the executable inherits argv0 from the wrapper.
+#                         (use instead of --argv0 '$0')
+# --set         VAR VAL : add VAR with value VAL to the executable’s
+#                         environment
+# --set-default VAR VAL : like --set, but only adds VAR if not already set in
+#                         the environment
+# --unset       VAR     : remove VAR from the environment
+# --chdir       DIR     : change working directory (use instead of --run "cd DIR")
+# --add-flags   FLAGS   : add FLAGS to invocation of executable
+
+# --prefix          ENV SEP VAL   : suffix/prefix ENV with VAL, separated by SEP
+# --suffix
+
+# To troubleshoot a binary wrapper after you compiled it,
+# use the `strings` command or open the binary file in a text editor.
+makeWrapper() {
+    assertExecutable "$1"
+    makeDocumentedCWrapper "$1" "${@:3}" | \
+      @CC@ \
+        -Wall -Werror -Wpedantic \
+        -Os \
+        -x c \
+        -o "$2" -
+}
+
+# Syntax: wrapProgram <PROGRAM> <MAKE-WRAPPER FLAGS...>
+wrapProgram() {
+    local prog="$1"
+    local hidden
+
+    assertExecutable "$prog"
+
+    hidden="$(dirname "$prog")/.$(basename "$prog")"-wrapped
+    while [ -e "$hidden" ]; do
+      hidden="${hidden}_"
+    done
+    mv "$prog" "$hidden"
+    # Silence warning about unexpanded $0:
+    # shellcheck disable=SC2016
+    makeWrapper "$hidden" "$prog" --inherit-argv0 "${@:2}"
+}
+
+# Generate source code for the wrapper in such a way that the wrapper inputs
+# will still be readable even after compilation
+# makeDocumentedCWrapper EXECUTABLE ARGS
+# ARGS: same as makeWrapper
+makeDocumentedCWrapper() {
+    local src docs
+    src=$(makeCWrapper "$@")
+    docs=$(docstring "$@")
+    printf '%s\n\n' "$src"
+    printf '%s\n' "$docs"
+}
+
+# makeCWrapper EXECUTABLE ARGS
+# ARGS: same as makeWrapper
+makeCWrapper() {
+    local argv0 inherit_argv0 n params cmd main flagsBefore flags executable length
+    local uses_prefix uses_suffix uses_assert uses_assert_success uses_stdio uses_asprintf
+    executable=$(escapeStringLiteral "$1")
+    params=("$@")
+    length=${#params[*]}
+    for ((n = 1; n < length; n += 1)); do
+        p="${params[n]}"
+        case $p in
+            --set)
+                cmd=$(setEnv "${params[n + 1]}" "${params[n + 2]}")
+                main="$main$cmd"$'\n'
+                n=$((n + 2))
+                [ $n -ge "$length" ] && main="$main#error makeCWrapper: $p takes 2 arguments"$'\n'
+            ;;
+            --set-default)
+                cmd=$(setDefaultEnv "${params[n + 1]}" "${params[n + 2]}")
+                main="$main$cmd"$'\n'
+                uses_stdio=1
+                uses_assert_success=1
+                n=$((n + 2))
+                [ $n -ge "$length" ] && main="$main#error makeCWrapper: $p takes 2 arguments"$'\n'
+            ;;
+            --unset)
+                cmd=$(unsetEnv "${params[n + 1]}")
+                main="$main$cmd"$'\n'
+                uses_stdio=1
+                uses_assert_success=1
+                n=$((n + 1))
+                [ $n -ge "$length" ] && main="$main#error makeCWrapper: $p takes 1 argument"$'\n'
+            ;;
+            --prefix)
+                cmd=$(setEnvPrefix "${params[n + 1]}" "${params[n + 2]}" "${params[n + 3]}")
+                main="$main$cmd"$'\n'
+                uses_prefix=1
+                uses_asprintf=1
+                uses_stdio=1
+                uses_assert_success=1
+                uses_assert=1
+                n=$((n + 3))
+                [ $n -ge "$length" ] && main="$main#error makeCWrapper: $p takes 3 arguments"$'\n'
+            ;;
+            --suffix)
+                cmd=$(setEnvSuffix "${params[n + 1]}" "${params[n + 2]}" "${params[n + 3]}")
+                main="$main$cmd"$'\n'
+                uses_suffix=1
+                uses_asprintf=1
+                uses_stdio=1
+                uses_assert_success=1
+                uses_assert=1
+                n=$((n + 3))
+                [ $n -ge "$length" ] && main="$main#error makeCWrapper: $p takes 3 arguments"$'\n'
+            ;;
+            --chdir)
+                cmd=$(changeDir "${params[n + 1]}")
+                main="$main$cmd"$'\n'
+                uses_stdio=1
+                uses_assert_success=1
+                n=$((n + 1))
+                [ $n -ge "$length" ] && main="$main#error makeCWrapper: $p takes 1 argument"$'\n'
+            ;;
+            --add-flags)
+                flags="${params[n + 1]}"
+                flagsBefore="$flagsBefore $flags"
+                uses_assert=1
+                n=$((n + 1))
+                [ $n -ge "$length" ] && main="$main#error makeCWrapper: $p takes 1 argument"$'\n'
+            ;;
+            --argv0)
+                argv0=$(escapeStringLiteral "${params[n + 1]}")
+                inherit_argv0=
+                n=$((n + 1))
+                [ $n -ge "$length" ] && main="$main#error makeCWrapper: $p takes 1 argument"$'\n'
+            ;;
+            --inherit-argv0)
+                # Whichever comes last of --argv0 and --inherit-argv0 wins
+                inherit_argv0=1
+            ;;
+            *) # Using an error macro, we will make sure the compiler gives an understandable error message
+                main="$main#error makeCWrapper: Unknown argument ${p}"$'\n'
+            ;;
+        esac
+    done
+    # shellcheck disable=SC2086
+    [ -z "$flagsBefore" ] || main="$main"${main:+$'\n'}$(addFlags $flagsBefore)$'\n'$'\n'
+    [ -z "$inherit_argv0" ] && main="${main}argv[0] = \"${argv0:-${executable}}\";"$'\n'
+    main="${main}return execv(\"${executable}\", argv);"$'\n'
+
+    [ -z "$uses_asprintf" ] || printf '%s\n' "#define _GNU_SOURCE         /* See feature_test_macros(7) */"
+    printf '%s\n' "#include <unistd.h>"
+    printf '%s\n' "#include <stdlib.h>"
+    [ -z "$uses_assert" ]   || printf '%s\n' "#include <assert.h>"
+    [ -z "$uses_stdio" ]    || printf '%s\n' "#include <stdio.h>"
+    [ -z "$uses_assert_success" ] || printf '\n%s\n' "#define assert_success(e) do { if ((e) < 0) { perror(#e); abort(); } } while (0)"
+    [ -z "$uses_prefix" ] || printf '\n%s\n' "$(setEnvPrefixFn)"
+    [ -z "$uses_suffix" ] || printf '\n%s\n' "$(setEnvSuffixFn)"
+    printf '\n%s' "int main(int argc, char **argv) {"
+    printf '\n%s' "$(indent4 "$main")"
+    printf '\n%s\n' "}"
+}
+
+addFlags() {
+    local result n flag flags var
+    var="argv_tmp"
+    flags=("$@")
+    for ((n = 0; n < ${#flags[*]}; n += 1)); do
+        flag=$(escapeStringLiteral "${flags[$n]}")
+        result="$result${var}[$((n+1))] = \"$flag\";"$'\n'
+    done
+    printf '%s\n' "char **$var = calloc($((n+1)) + argc, sizeof(*$var));"
+    printf '%s\n' "assert($var != NULL);"
+    printf '%s\n' "${var}[0] = argv[0];"
+    printf '%s' "$result"
+    printf '%s\n' "for (int i = 1; i < argc; ++i) {"
+    printf '%s\n' "    ${var}[$n + i] = argv[i];"
+    printf '%s\n' "}"
+    printf '%s\n' "${var}[$n + argc] = NULL;"
+    printf '%s\n' "argv = $var;"
+}
+
+# chdir DIR
+changeDir() {
+    local dir
+    dir=$(escapeStringLiteral "$1")
+    printf '%s' "assert_success(chdir(\"$dir\"));"
+}
+
+# prefix ENV SEP VAL
+setEnvPrefix() {
+    local env sep val
+    env=$(escapeStringLiteral "$1")
+    sep=$(escapeStringLiteral "$2")
+    val=$(escapeStringLiteral "$3")
+    printf '%s' "set_env_prefix(\"$env\", \"$sep\", \"$val\");"
+    assertValidEnvName "$1"
+}
+
+# suffix ENV SEP VAL
+setEnvSuffix() {
+    local env sep val
+    env=$(escapeStringLiteral "$1")
+    sep=$(escapeStringLiteral "$2")
+    val=$(escapeStringLiteral "$3")
+    printf '%s' "set_env_suffix(\"$env\", \"$sep\", \"$val\");"
+    assertValidEnvName "$1"
+}
+
+# setEnv KEY VALUE
+setEnv() {
+    local key value
+    key=$(escapeStringLiteral "$1")
+    value=$(escapeStringLiteral "$2")
+    printf '%s' "putenv(\"$key=$value\");"
+    assertValidEnvName "$1"
+}
+
+# setDefaultEnv KEY VALUE
+setDefaultEnv() {
+    local key value
+    key=$(escapeStringLiteral "$1")
+    value=$(escapeStringLiteral "$2")
+    printf '%s' "assert_success(setenv(\"$key\", \"$value\", 0));"
+    assertValidEnvName "$1"
+}
+
+# unsetEnv KEY
+unsetEnv() {
+    local key
+    key=$(escapeStringLiteral "$1")
+    printf '%s' "assert_success(unsetenv(\"$key\"));"
+    assertValidEnvName "$1"
+}
+
+# Makes it safe to insert STRING within quotes in a C String Literal.
+# escapeStringLiteral STRING
+escapeStringLiteral() {
+    local result
+    result=${1//$'\\'/$'\\\\'}
+    result=${result//\"/'\"'}
+    result=${result//$'\n'/"\n"}
+    result=${result//$'\r'/"\r"}
+    printf '%s' "$result"
+}
+
+# Indents every non-empty line by 4 spaces. To avoid trailing whitespace, we don't indent empty lines
+# indent4 TEXT_BLOCK
+indent4() {
+    printf '%s' "$1" | awk '{ if ($0 != "") { print "    "$0 } else { print $0 }}'
+}
+
+assertValidEnvName() {
+    case "$1" in
+        *=*) printf '\n%s\n' "#error Illegal environment variable name \`$1\` (cannot contain \`=\`)";;
+        "")  printf '\n%s\n' "#error Environment variable name can't be empty.";;
+    esac
+}
+
+setEnvPrefixFn() {
+    printf '%s' "\
+void set_env_prefix(char *env, char *sep, char *prefix) {
+    char *existing = getenv(env);
+    if (existing) {
+        char *val;
+        assert_success(asprintf(&val, \"%s%s%s\", prefix, sep, existing));
+        assert_success(setenv(env, val, 1));
+        free(val);
+    } else {
+        assert_success(setenv(env, prefix, 1));
+    }
+}
+"
+}
+
+setEnvSuffixFn() {
+    printf '%s' "\
+void set_env_suffix(char *env, char *sep, char *suffix) {
+    char *existing = getenv(env);
+    if (existing) {
+        char *val;
+        assert_success(asprintf(&val, \"%s%s%s\", existing, sep, suffix));
+        assert_success(setenv(env, val, 1));
+        free(val);
+    } else {
+        assert_success(setenv(env, suffix, 1));
+    }
+}
+"
+}
+
+# Embed a C string which shows up as readable text in the compiled binary wrapper
+# documentationString ARGS
+docstring() {
+    printf '%s' "const char * DOCSTRING = \"$(escapeStringLiteral "
+
+
+# ------------------------------------------------------------------------------------
+# The C-code for this binary wrapper has been generated using the following command:
+
+
+makeCWrapper $(formatArgs "$@")
+
+
+# (Use \`nix-shell -p makeBinaryWrapper\` to get access to makeCWrapper in your shell)
+# ------------------------------------------------------------------------------------
+
+
+")\";"
+}
+
+# formatArgs EXECUTABLE ARGS
+formatArgs() {
+    printf '%s' "$1"
+    shift
+    while [ $# -gt 0 ]; do
+        case "$1" in
+            --set)
+                formatArgsLine 2 "$@"
+                shift 2
+            ;;
+            --set-default)
+                formatArgsLine 2 "$@"
+                shift 2
+            ;;
+            --unset)
+                formatArgsLine 1 "$@"
+                shift 1
+            ;;
+            --prefix)
+                formatArgsLine 3 "$@"
+                shift 3
+            ;;
+            --suffix)
+                formatArgsLine 3 "$@"
+                shift 3
+            ;;
+            --chdir)
+                formatArgsLine 1 "$@"
+                shift 1
+            ;;
+            --add-flags)
+                formatArgsLine 1 "$@"
+                shift 1
+            ;;
+            --argv0)
+                formatArgsLine 1 "$@"
+                shift 1
+            ;;
+            --inherit-argv0)
+                formatArgsLine 0 "$@"
+            ;;
+        esac
+        shift
+    done
+    printf '%s\n' ""
+}
+
+# formatArgsLine ARG_COUNT ARGS
+formatArgsLine() {
+    local ARG_COUNT LENGTH
+    ARG_COUNT=$1
+    LENGTH=$#
+    shift
+    printf '%s' $' \\\n    '"$1"
+    shift
+    while [ "$ARG_COUNT" -gt $((LENGTH - $# - 2)) ]; do
+        printf ' %s' "${1@Q}"
+        shift
+    done
+}

pkgs/test/default.nix

@@ -35,6 +35,8 @@ with pkgs;
 
   macOSSierraShared = callPackage ./macos-sierra-shared {};
 
+  make-binary-wrapper = callPackage ./make-binary-wrapper { inherit makeBinaryWrapper; };
+
   cross = callPackage ./cross {};
 
   php = recurseIntoAttrs (callPackages ./php {});

pkgs/test/make-binary-wrapper/add-flags.c

@@ -0,0 +1,21 @@
+#include <unistd.h>
+#include <stdlib.h>
+#include <assert.h>
+
+int main(int argc, char **argv) {
+    char **argv_tmp = calloc(5 + argc, sizeof(*argv_tmp));
+    assert(argv_tmp != NULL);
+    argv_tmp[0] = argv[0];
+    argv_tmp[1] = "-x";
+    argv_tmp[2] = "-y";
+    argv_tmp[3] = "-z";
+    argv_tmp[4] = "-abc";
+    for (int i = 1; i < argc; ++i) {
+        argv_tmp[4 + i] = argv[i];
+    }
+    argv_tmp[4 + argc] = NULL;
+    argv = argv_tmp;
+
+    argv[0] = "/send/me/flags";
+    return execv("/send/me/flags", argv);
+}

pkgs/test/make-binary-wrapper/add-flags.cmdline

@@ -0,0 +1,2 @@
+    --add-flags "-x -y -z" \
+    --add-flags -abc

pkgs/test/make-binary-wrapper/add-flags.env

@@ -0,0 +1,6 @@
+CWD=SUBST_CWD
+SUBST_ARGV0
+-x
+-y
+-z
+-abc

pkgs/test/make-binary-wrapper/argv0.c

@@ -0,0 +1,7 @@
+#include <unistd.h>
+#include <stdlib.h>
+
+int main(int argc, char **argv) {
+    argv[0] = "alternative-name";
+    return execv("/send/me/flags", argv);
+}

pkgs/test/make-binary-wrapper/argv0.cmdline

@@ -0,0 +1 @@
+    --argv0 alternative-name

pkgs/test/make-binary-wrapper/argv0.env

@@ -0,0 +1,2 @@
+CWD=SUBST_CWD
+alternative-name

pkgs/test/make-binary-wrapper/basic.c

@@ -0,0 +1,7 @@
+#include <unistd.h>
+#include <stdlib.h>
+
+int main(int argc, char **argv) {
+    argv[0] = "/send/me/flags";
+    return execv("/send/me/flags", argv);
+}

pkgs/test/make-binary-wrapper/basic.env

@@ -0,0 +1,2 @@
+CWD=SUBST_CWD
+SUBST_ARGV0

pkgs/test/make-binary-wrapper/chdir.c

@@ -0,0 +1,11 @@
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#define assert_success(e) do { if ((e) < 0) { perror(#e); abort(); } } while (0)
+
+int main(int argc, char **argv) {
+    assert_success(chdir("/tmp/foo"));
+    argv[0] = "/send/me/flags";
+    return execv("/send/me/flags", argv);
+}

pkgs/test/make-binary-wrapper/chdir.cmdline

@@ -0,0 +1 @@
+    --chdir /tmp/foo

pkgs/test/make-binary-wrapper/chdir.env

@@ -0,0 +1,2 @@
+CWD=/tmp/foo
+SUBST_ARGV0

pkgs/test/make-binary-wrapper/combination.c

@@ -0,0 +1,53 @@
+#define _GNU_SOURCE         /* See feature_test_macros(7) */
+#include <unistd.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <stdio.h>
+
+#define assert_success(e) do { if ((e) < 0) { perror(#e); abort(); } } while (0)
+
+void set_env_prefix(char *env, char *sep, char *prefix) {
+    char *existing = getenv(env);
+    if (existing) {
+        char *val;
+        assert_success(asprintf(&val, "%s%s%s", prefix, sep, existing));
+        assert_success(setenv(env, val, 1));
+        free(val);
+    } else {
+        assert_success(setenv(env, prefix, 1));
+    }
+}
+
+void set_env_suffix(char *env, char *sep, char *suffix) {
+    char *existing = getenv(env);
+    if (existing) {
+        char *val;
+        assert_success(asprintf(&val, "%s%s%s", existing, sep, suffix));
+        assert_success(setenv(env, val, 1));
+        free(val);
+    } else {
+        assert_success(setenv(env, suffix, 1));
+    }
+}
+
+int main(int argc, char **argv) {
+    assert_success(setenv("MESSAGE", "HELLO", 0));
+    set_env_prefix("PATH", ":", "/usr/bin/");
+    set_env_suffix("PATH", ":", "/usr/local/bin/");
+    putenv("MESSAGE2=WORLD");
+
+    char **argv_tmp = calloc(4 + argc, sizeof(*argv_tmp));
+    assert(argv_tmp != NULL);
+    argv_tmp[0] = argv[0];
+    argv_tmp[1] = "-x";
+    argv_tmp[2] = "-y";
+    argv_tmp[3] = "-z";
+    for (int i = 1; i < argc; ++i) {
+        argv_tmp[3 + i] = argv[i];
+    }
+    argv_tmp[3 + argc] = NULL;
+    argv = argv_tmp;
+
+    argv[0] = "my-wrapper";
+    return execv("/send/me/flags", argv);
+}

pkgs/test/make-binary-wrapper/combination.cmdline

@@ -0,0 +1,6 @@
+    --argv0 my-wrapper \
+    --set-default MESSAGE HELLO \
+    --prefix PATH : /usr/bin/ \
+    --suffix PATH : /usr/local/bin/ \
+    --add-flags "-x -y -z" \
+    --set MESSAGE2 WORLD

pkgs/test/make-binary-wrapper/combination.env

@@ -0,0 +1,8 @@
+MESSAGE=HELLO
+PATH=/usr/bin/:/usr/local/bin/
+MESSAGE2=WORLD
+CWD=SUBST_CWD
+my-wrapper
+-x
+-y
+-z

pkgs/test/make-binary-wrapper/default.nix

@@ -0,0 +1,54 @@
+{ lib, coreutils, python3, gcc, writeText, writeScript, runCommand, makeBinaryWrapper }:
+
+let
+  env = { nativeBuildInputs = [ makeBinaryWrapper ]; };
+  envCheck = runCommand "envcheck" env ''
+    ${gcc}/bin/cc -Wall -Werror -Wpedantic -o $out ${./envcheck.c}
+  '';
+  makeGoldenTest = testname: runCommand "test-wrapper_${testname}" env ''
+    mkdir -p /tmp/foo
+
+    params=$(<"${./.}/${testname}.cmdline")
+    eval "makeCWrapper /send/me/flags $params" > wrapper.c
+
+    diff wrapper.c "${./.}/${testname}.c"
+
+    if [ -f "${./.}/${testname}.env" ]; then
+      eval "makeWrapper ${envCheck} wrapped $params"
+      env -i ./wrapped > env.txt
+      sed "s#SUBST_ARGV0#${envCheck}#;s#SUBST_CWD#$PWD#" \
+        "${./.}/${testname}.env" > golden-env.txt
+      if ! diff env.txt golden-env.txt; then
+        echo "env/argv should be:"
+        cat golden-env.txt
+        echo "env/argv output is:"
+        cat env.txt
+        exit 1
+      fi
+    else
+      # without a golden env, we expect the wrapper compilation to fail
+      ! eval "makeWrapper ${envCheck} wrapped $params" &> error.txt
+    fi
+
+    cp wrapper.c $out
+  '';
+  tests = let
+    names = [
+      "add-flags"
+      "argv0"
+      "basic"
+      "chdir"
+      "combination"
+      "env"
+      "inherit-argv0"
+      "invalid-env"
+      "prefix"
+      "suffix"
+    ];
+    f = name: lib.nameValuePair name (makeGoldenTest name);
+  in builtins.listToAttrs (builtins.map f names);
+in writeText "make-binary-wrapper-test" ''
+  ${lib.concatStringsSep "\n" (lib.mapAttrsToList (_: test: ''
+    "${test.name}" "${test}"
+  '') tests)}
+'' // tests

pkgs/test/make-binary-wrapper/env.c

@@ -0,0 +1,14 @@
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#define assert_success(e) do { if ((e) < 0) { perror(#e); abort(); } } while (0)
+
+int main(int argc, char **argv) {
+    putenv("PART1=HELLO");
+    assert_success(setenv("PART2", "WORLD", 0));
+    assert_success(unsetenv("SOME_OTHER_VARIABLE"));
+    putenv("PART3=\"!!\n\"");
+    argv[0] = "/send/me/flags";
+    return execv("/send/me/flags", argv);
+}

pkgs/test/make-binary-wrapper/env.cmdline

@@ -0,0 +1,4 @@
+    --set PART1 HELLO \
+    --set-default PART2 WORLD \
+    --unset SOME_OTHER_VARIABLE \
+    --set PART3 $'"!!\n"'

pkgs/test/make-binary-wrapper/env.env

@@ -0,0 +1,6 @@
+PART1=HELLO
+PART2=WORLD
+PART3="!!
+"
+CWD=SUBST_CWD
+SUBST_ARGV0

pkgs/test/make-binary-wrapper/envcheck.c

@@ -0,0 +1,22 @@
+#include <limits.h>
+#include <stdio.h>
+#include <unistd.h>
+
+int main(int argc, char **argv, char **envp) {
+  for (char **env = envp; *env != 0; ++env) {
+    puts(*env);
+  }
+
+   char cwd[PATH_MAX];
+   if (getcwd(cwd, sizeof(cwd))) {
+     printf("CWD=%s\n", cwd);
+   } else {
+     perror("getcwd() error");
+     return 1;
+   }
+
+  for (int i=0; i < argc; ++i) {
+    puts(argv[i]);
+  }
+  return 0;
+}

pkgs/test/make-binary-wrapper/inherit-argv0.c

@@ -0,0 +1,6 @@
+#include <unistd.h>
+#include <stdlib.h>
+
+int main(int argc, char **argv) {
+    return execv("/send/me/flags", argv);
+}

pkgs/test/make-binary-wrapper/inherit-argv0.cmdline

@@ -0,0 +1 @@
+    --inherit-argv0

pkgs/test/make-binary-wrapper/inherit-argv0.env

@@ -0,0 +1,2 @@
+CWD=SUBST_CWD
+./wrapped

pkgs/test/make-binary-wrapper/invalid-env.c

@@ -0,0 +1,14 @@
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#define assert_success(e) do { if ((e) < 0) { perror(#e); abort(); } } while (0)
+
+int main(int argc, char **argv) {
+    putenv("==TEST1");
+    #error Illegal environment variable name `=` (cannot contain `=`)
+    assert_success(setenv("", "TEST2", 0));
+    #error Environment variable name can't be empty.
+    argv[0] = "/send/me/flags";
+    return execv("/send/me/flags", argv);
+}

pkgs/test/make-binary-wrapper/invalid-env.cmdline

@@ -0,0 +1,2 @@
+    --set "=" "TEST1" \
+    --set-default "" "TEST2"

pkgs/test/make-binary-wrapper/prefix.c

@@ -0,0 +1,26 @@
+#define _GNU_SOURCE         /* See feature_test_macros(7) */
+#include <unistd.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <stdio.h>
+
+#define assert_success(e) do { if ((e) < 0) { perror(#e); abort(); } } while (0)
+
+void set_env_prefix(char *env, char *sep, char *prefix) {
+    char *existing = getenv(env);
+    if (existing) {
+        char *val;
+        assert_success(asprintf(&val, "%s%s%s", prefix, sep, existing));
+        assert_success(setenv(env, val, 1));
+        free(val);
+    } else {
+        assert_success(setenv(env, prefix, 1));
+    }
+}
+
+int main(int argc, char **argv) {
+    set_env_prefix("PATH", ":", "/usr/bin/");
+    set_env_prefix("PATH", ":", "/usr/local/bin/");
+    argv[0] = "/send/me/flags";
+    return execv("/send/me/flags", argv);
+}

pkgs/test/make-binary-wrapper/prefix.cmdline

@@ -0,0 +1,2 @@
+    --prefix PATH : /usr/bin/ \
+    --prefix PATH : /usr/local/bin/

pkgs/test/make-binary-wrapper/prefix.env

@@ -0,0 +1,3 @@
+PATH=/usr/local/bin/:/usr/bin/
+CWD=SUBST_CWD
+SUBST_ARGV0

pkgs/test/make-binary-wrapper/suffix.c

@@ -0,0 +1,26 @@
+#define _GNU_SOURCE         /* See feature_test_macros(7) */
+#include <unistd.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <stdio.h>
+
+#define assert_success(e) do { if ((e) < 0) { perror(#e); abort(); } } while (0)
+
+void set_env_suffix(char *env, char *sep, char *suffix) {
+    char *existing = getenv(env);
+    if (existing) {
+        char *val;
+        assert_success(asprintf(&val, "%s%s%s", existing, sep, suffix));
+        assert_success(setenv(env, val, 1));
+        free(val);
+    } else {
+        assert_success(setenv(env, suffix, 1));
+    }
+}
+
+int main(int argc, char **argv) {
+    set_env_suffix("PATH", ":", "/usr/bin/");
+    set_env_suffix("PATH", ":", "/usr/local/bin/");
+    argv[0] = "/send/me/flags";
+    return execv("/send/me/flags", argv);
+}

pkgs/test/make-binary-wrapper/suffix.cmdline

@@ -0,0 +1,2 @@
+    --suffix PATH : /usr/bin/ \
+    --suffix PATH : /usr/local/bin/

pkgs/test/make-binary-wrapper/suffix.env

@@ -0,0 +1,3 @@
+PATH=/usr/bin/:/usr/local/bin/
+CWD=SUBST_CWD
+SUBST_ARGV0

pkgs/top-level/all-packages.nix

@@ -688,6 +688,21 @@ with pkgs;
   makeWrapper = makeSetupHook { deps = [ dieHook ]; substitutions = { shell = targetPackages.runtimeShell; }; }
                               ../build-support/setup-hooks/make-wrapper.sh;
 
+  makeBinaryWrapper = let
+    f = { cc, sanitizers }: let
+      san = lib.concatMapStringsSep " " (s: "-fsanitize=${s}") sanitizers;
+      script = runCommand "make-binary-wrapper.sh" {} ''
+        substitute ${../build-support/setup-hooks/make-binary-wrapper.sh} $out \
+          --replace " @CC@ " " ${cc}/bin/cc ${san} "
+      '';
+    in
+      makeSetupHook { deps = [ dieHook ]; } script;
+  in
+    lib.makeOverridable f {
+      cc = stdenv.cc.cc;
+      sanitizers = [ "undefined" "address" ];
+    };
+
   makeModulesClosure = { kernel, firmware, rootModules, allowMissing ? false }:
     callPackage ../build-support/kernel/modules-closure.nix {
       inherit kernel firmware rootModules allowMissing;