forked from mirrors/nixpkgs
228 lines
7.6 KiB
Bash
228 lines
7.6 KiB
Bash
# Generate a binary executable wrapper for wrapping an executable.
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# The binary is compiled from generated C-code using gcc.
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# makeBinaryWrapper EXECUTABLE OUT_PATH ARGS
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# ARGS:
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# --argv0 NAME : set name of executed process to NAME
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# (otherwise it’s called …-wrapped)
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# --set VAR VAL : add VAR with value VAL to the executable’s
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# environment
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# --set-default VAR VAL : like --set, but only adds VAR if not already set in
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# the environment
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# --unset VAR : remove VAR from the environment
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# --add-flags FLAGS : add FLAGS to invocation of executable
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# --prefix ENV SEP VAL : suffix/prefix ENV with VAL, separated by SEP
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# --suffix
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# To troubleshoot a binary wrapper after you compiled it,
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# use the `strings` command or open the binary file in a text editor.
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makeBinaryWrapper() {
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makeDocumentedCWrapper "$1" "${@:3}" | gcc -Os -x c -o "$2" -
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}
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# Generate source code for the wrapper in such a way that the wrapper source code
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# will still be readable even after compilation
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# makeDocumentedCWrapper EXECUTABLE ARGS
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# ARGS: same as makeBinaryWrapper
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makeDocumentedCWrapper() {
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local src docs
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src=$(makeCWrapper "$@")
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docs=$(documentationString "$src")
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printf '%s\n\n' "$src"
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printf '%s\n' "$docs"
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}
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# makeCWrapper EXECUTABLE ARGS
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# ARGS: same as makeBinaryWrapper
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makeCWrapper() {
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local argv0 n params cmd main flagsBefore flags executable params length
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local uses_prefix uses_suffix uses_concat3
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executable=$(escapeStringLiteral "$1")
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params=("$@")
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length=${#params[*]}
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for ((n = 1; n < length; n += 1)); do
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p="${params[n]}"
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case $p in
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--set)
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cmd=$(setEnv "${params[n + 1]}" "${params[n + 2]}")
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main="$main $cmd"$'\n'
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n=$((n + 2))
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[ $n -ge "$length" ] && main="$main #error makeCWrapper: $p takes 2 arguments"$'\n'
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;;
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--set-default)
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cmd=$(setDefaultEnv "${params[n + 1]}" "${params[n + 2]}")
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main="$main $cmd"$'\n'
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n=$((n + 2))
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[ $n -ge "$length" ] && main="$main #error makeCWrapper: $p takes 2 arguments"$'\n'
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;;
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--unset)
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cmd=$(unsetEnv "${params[n + 1]}")
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main="$main $cmd"$'\n'
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n=$((n + 1))
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[ $n -ge "$length" ] && main="$main #error makeCWrapper: $p takes 1 argument"$'\n'
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;;
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--prefix)
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cmd=$(setEnvPrefix "${params[n + 1]}" "${params[n + 2]}" "${params[n + 3]}")
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main="$main $cmd"$'\n'
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uses_prefix=1
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uses_concat3=1
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n=$((n + 3))
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[ $n -ge "$length" ] && main="$main #error makeCWrapper: $p takes 3 arguments"$'\n'
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;;
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--suffix)
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cmd=$(setEnvSuffix "${params[n + 1]}" "${params[n + 2]}" "${params[n + 3]}")
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main="$main $cmd"$'\n'
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uses_suffix=1
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uses_concat3=1
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n=$((n + 3))
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[ $n -ge "$length" ] && main="$main #error makeCWrapper: $p takes 3 arguments"$'\n'
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;;
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--add-flags)
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flags="${params[n + 1]}"
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flagsBefore="$flagsBefore $flags"
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n=$((n + 1))
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[ $n -ge "$length" ] && main="$main #error makeCWrapper: $p takes 1 argument"$'\n'
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;;
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--argv0)
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argv0=$(escapeStringLiteral "${params[n + 1]}")
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n=$((n + 1))
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[ $n -ge "$length" ] && main="$main #error makeCWrapper: $p takes 1 argument"$'\n'
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;;
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*) # Using an error macro, we will make sure the compiler gives an understandable error message
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main="$main #error makeCWrapper: Uknown argument ${p}"$'\n'
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;;
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esac
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done
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# shellcheck disable=SC2086
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[ -z "$flagsBefore" ] || main="$main"${main:+$'\n'}$(addFlags $flagsBefore)$'\n'$'\n'
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main="$main argv[0] = \"${argv0:-${executable}}\";"$'\n'
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main="$main return execv(\"${executable}\", argv);"$'\n'
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printf '%s\n' "#include <unistd.h>"
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printf '%s\n' "#include <stdlib.h>"
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[ -z "$uses_concat3" ] || printf '%s\n' "#include <string.h>"
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[ -z "$uses_concat3" ] || printf '\n%s\n' "$(concat3Fn)"
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[ -z "$uses_prefix" ] || printf '\n%s\n' "$(setEnvPrefixFn)"
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[ -z "$uses_suffix" ] || printf '\n%s\n' "$(setEnvSuffixFn)"
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printf '\n%s' "int main(int argc, char **argv) {"
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printf '\n%s' "$main"
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printf '%s\n' "}"
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}
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addFlags() {
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local result n flag flags var
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var="argv_tmp"
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flags=("$@")
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for ((n = 0; n < ${#flags[*]}; n += 1)); do
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flag=$(escapeStringLiteral "${flags[$n]}")
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result="$result ${var}[$((n+1))] = \"$flag\";"$'\n'
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done
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printf ' %s\n' "char **$var = malloc(sizeof(*$var) * ($((n+1)) + argc));"
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printf ' %s\n' "${var}[0] = argv[0];"
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printf '%s' "$result"
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printf ' %s\n' "for (int i = 1; i < argc; ++i) {"
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printf ' %s\n' " ${var}[$n + i] = argv[i];"
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printf ' %s\n' "}"
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printf ' %s\n' "${var}[$n + argc] = NULL;"
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printf ' %s\n' "argv = $var;"
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}
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# prefix ENV SEP VAL
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setEnvPrefix() {
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local env sep val
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env=$(escapeStringLiteral "$1")
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sep=$(escapeStringLiteral "$2")
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val=$(escapeStringLiteral "$3")
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printf '%s' "set_env_prefix(\"$env\", \"$sep\", \"$val\");"
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}
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# suffix ENV SEP VAL
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setEnvSuffix() {
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local env sep val
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env=$(escapeStringLiteral "$1")
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sep=$(escapeStringLiteral "$2")
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val=$(escapeStringLiteral "$3")
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printf '%s' "set_env_suffix(\"$env\", \"$sep\", \"$val\");"
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}
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# setEnv KEY VALUE
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setEnv() {
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local key value
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key=$(escapeStringLiteral "$1")
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value=$(escapeStringLiteral "$2")
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printf '%s' "putenv(\"$key=$value\");"
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}
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# setDefaultEnv KEY VALUE
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setDefaultEnv() {
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local key value
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key=$(escapeStringLiteral "$1")
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value=$(escapeStringLiteral "$2")
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printf '%s' "setenv(\"$key\", \"$value\", 0);"
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}
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# unsetEnv KEY
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unsetEnv() {
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local key
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key=$(escapeStringLiteral "$1")
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printf '%s' "unsetenv(\"$key\");"
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}
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# Put the entire source code into const char* SOURCE_CODE to make it readable after compilation.
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# documentationString SOURCE_CODE
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documentationString() {
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local docs
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docs=$(escapeStringLiteral $'\n----------\n// This binary wrapper was compiled from the following generated C-code:\n'"$1"$'\n----------\n')
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printf '%s' "const char * SOURCE_CODE = \"$docs\";"
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}
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# Makes it safe to insert STRING within quotes in a C String Literal.
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# escapeStringLiteral STRING
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escapeStringLiteral() {
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local result
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result=${1//$'\\'/$'\\\\'}
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result=${result//\"/'\"'}
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result=${result//$'\n'/"\n"}
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result=${result//$'\r'/"\r"}
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printf '%s' "$result"
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}
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concat3Fn() {
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printf '%s' "\
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char *concat3(char *x, char *y, char *z) {
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int xn = strlen(x);
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int yn = strlen(y);
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int zn = strlen(z);
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char *res = malloc(sizeof(*res)*(xn + yn + zn + 1));
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strncpy(res, x, xn);
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strncpy(res + xn, y, yn);
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strncpy(res + xn + yn, z, zn);
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res[xn + yn + zn] = '\0';
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return res;
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}
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"
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}
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setEnvPrefixFn() {
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printf '%s' "\
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void set_env_prefix(char *env, char *sep, char *val) {
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char *existing = getenv(env);
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if (existing) val = concat3(val, sep, existing);
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setenv(env, val, 1);
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if (existing) free(val);
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}
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"
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}
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setEnvSuffixFn() {
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printf '%s' "\
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void set_env_suffix(char *env, char *sep, char *val) {
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char *existing = getenv(env);
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if (existing) val = concat3(existing, sep, val);
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setenv(env, val, 1);
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if (existing) free(val);
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}
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"
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}
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