1 files changed, 384 insertions, 0 deletions
diff --git a/pkgs/build-support/setup-hooks/make-binary-wrapper.sh b/pkgs/build-support/setup-hooks/make-binary-wrapper.sh
new file mode 100644
index 000000000000..abc929cb89db
--- /dev/null
+++ b/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
+}