mirror of
https://github.com/NixOS/nixpkgs.git
synced 2026-08-27 02:34:53 +00:00
d75cae80fa
When setting a prefix for a path-like environment variable, the deduplication code in set_env_prefix reads past the NUL byte at the end of the env val and into the next entry. This corrupts the resultant env value with data from the next env var, or other data sitting after it.
546 lines
17 KiB
Bash
546 lines
17 KiB
Bash
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set -euo pipefail
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# Assert that FILE exists and is executable
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#
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# assertExecutable FILE
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assertExecutable() {
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local file="$1"
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[[ -e "$file" ]] || \
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die "Cannot wrap '$file' because it does not exist"
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[[ -f "$file" && -x "$file" ]] || \
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die "Cannot wrap '$file' because it is not an executable file"
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}
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# 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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# makeWrapper EXECUTABLE OUT_PATH ARGS
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# ARGS:
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# --argv0 NAME : set the name of the executed process to NAME
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# (if unset or empty, defaults to EXECUTABLE)
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# --inherit-argv0 : the executable inherits argv0 from the wrapper.
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# (use instead of --argv0 '$0')
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# --resolve-argv0 : if argv0 doesn't include a / character, resolve it against PATH
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# --set VAR VAL : add VAR with value VAL to the executable's 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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# --chdir DIR : change working directory (use instead of --run "cd DIR")
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# --add-flag ARG : prepend the single argument ARG to the invocation of the executable
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# (that is, *before* any arguments passed on the command line)
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# --append-flag ARG : append the single argument ARG to the invocation of the executable
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# (that is, *after* any arguments passed on the command line)
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# --add-flags ARGS : prepend the whitespace-separated list of arguments ARGS to the invocation of the executable
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# --append-flags ARGS : append the whitespace-separated list of arguments ARGS to the invocation of the 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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makeWrapper() { makeBinaryWrapper "$@"; }
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makeBinaryWrapper() {
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local NIX_CFLAGS_COMPILE= NIX_CFLAGS_LINK=
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local original="$1"
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local wrapper="$2"
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shift 2
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assertExecutable "$original"
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mkdir -p "$(dirname "$wrapper")"
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makeDocumentedCWrapper "$original" "$@" | \
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@cc@ \
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-Wall -Werror -Wpedantic \
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-Wno-overlength-strings \
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-Os \
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-x c \
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-o "$wrapper" -
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}
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# Syntax: wrapProgram <PROGRAM> <MAKE-WRAPPER FLAGS...>
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wrapProgram() { wrapProgramBinary "$@"; }
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wrapProgramBinary() {
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local prog="$1"
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local hidden
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assertExecutable "$prog"
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hidden="$(dirname "$prog")/.$(basename "$prog")"-wrapped
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while [ -e "$hidden" ]; do
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hidden="${hidden}_"
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done
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mv "$prog" "$hidden"
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makeBinaryWrapper "$hidden" "$prog" --inherit-argv0 "${@:2}"
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}
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# Generate source code for the wrapper in such a way that the wrapper inputs
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# will still be readable even after compilation
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# makeDocumentedCWrapper EXECUTABLE ARGS
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# ARGS: same as makeWrapper
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makeDocumentedCWrapper() {
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local src docs
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src=$(makeCWrapper "$@")
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docs=$(docstring "$@")
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printf '%s\n\n' "$src"
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printf '%s\n' "$docs"
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}
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# makeCWrapper EXECUTABLE ARGS
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# ARGS: same as makeWrapper
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makeCWrapper() {
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local argv0 inherit_argv0 n params cmd main flags executable length
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local uses_sep_surround_check uses_prefix uses_suffix uses_assert uses_assert_success uses_stdio uses_asprintf
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local flagsBefore=() flagsAfter=()
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executable=$(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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uses_stdio=1
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uses_assert_success=1
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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"$'\n'
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uses_stdio=1
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uses_assert_success=1
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n=$((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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--prefix)
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cmd=$(setEnvPrefix "${params[n + 1]}" "${params[n + 2]}" "${params[n + 3]}")
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main="$main$cmd"$'\n'
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uses_sep_surround_check=1
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uses_prefix=1
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uses_asprintf=1
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uses_stdio=1
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uses_string=1
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uses_assert_success=1
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uses_assert=1
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n=$((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"$'\n'
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uses_sep_surround_check=1
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uses_suffix=1
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uses_asprintf=1
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uses_stdio=1
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uses_string=1
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uses_assert_success=1
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uses_assert=1
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n=$((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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--chdir)
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cmd=$(changeDir "${params[n + 1]}")
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main="$main$cmd"$'\n'
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uses_stdio=1
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uses_assert_success=1
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n=$((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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--add-flag)
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flagsBefore+=("${params[n + 1]}")
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uses_assert=1
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n=$((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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--append-flag)
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flagsAfter+=("${params[n + 1]}")
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uses_assert=1
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n=$((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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--add-flags)
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read -ra flags <<< "${params[n + 1]}"
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flagsBefore+=("${flags[@]}")
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uses_assert=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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--append-flags)
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read -ra flags <<< "${params[n + 1]}"
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flagsAfter+=("${flags[@]}")
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uses_assert=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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--argv0)
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argv0=$(escapeStringLiteral "${params[n + 1]}")
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inherit_argv0=
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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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--inherit-argv0)
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# Whichever comes last of --argv0 and --inherit-argv0 wins
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inherit_argv0=1
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;;
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--resolve-argv0)
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# this gets processed after other argv0 flags
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uses_stdio=1
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uses_string=1
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resolve_argv0=1
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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: Unknown argument ${p}"$'\n'
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;;
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esac
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done
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(( ${#flagsBefore[@]} + ${#flagsAfter[@]} > 0 )) && main="$main"${main:+$'\n'}$(addFlags flagsBefore flagsAfter)$'\n'$'\n'
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[ -z "$inherit_argv0" ] && main="${main}argv[0] = \"${argv0:-${executable}}\";"$'\n'
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[ -z "$resolve_argv0" ] || main="${main}argv[0] = resolve_argv0(argv[0]);"$'\n'
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main="${main}return execv(\"${executable}\", argv);"$'\n'
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[ -z "$uses_asprintf" ] || printf '%s\n' "#define _GNU_SOURCE /* See feature_test_macros(7) */"
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printf '%s\n' "#include <unistd.h>"
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printf '%s\n' "#include <stdlib.h>"
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[ -z "$uses_assert" ] || printf '%s\n' "#include <assert.h>"
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[ -z "$uses_stdio" ] || printf '%s\n' "#include <stdio.h>"
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[ -z "$uses_string" ] || printf '%s\n' "#include <string.h>"
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[ -z "$uses_assert_success" ] || printf '\n%s\n' "#define assert_success(e) do { if ((e) < 0) { perror(#e); abort(); } } while (0)"
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[ -z "$uses_sep_surround_check" ] || printf '\n%s\n' "$(setSepSurroundCheck)"
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[ -z "$uses_prefix" ] || printf '\n%s\n' "$(setEnvPrefixFn)"
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[ -z "$uses_suffix" ] || printf '\n%s\n' "$(setEnvSuffixFn)"
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[ -z "$resolve_argv0" ] || printf '\n%s\n' "$(resolveArgv0Fn)"
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printf '\n%s' "int main(int argc, char **argv) {"
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printf '\n%s' "$(indent4 "$main")"
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printf '\n%s\n' "}"
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}
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addFlags() {
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local n flag var
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local -n before=$1
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local -n after=$2
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var="argv_tmp"
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printf '%s\n' "char **$var = calloc(${#before[@]} + argc + ${#after[@]} + 1, sizeof(*$var));"
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printf '%s\n' "assert($var != NULL);"
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printf '%s\n' "${var}[0] = argv[0];"
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for ((n = 0; n < ${#before[@]}; n += 1)); do
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flag=$(escapeStringLiteral "${before[n]}")
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printf '%s\n' "${var}[$((n + 1))] = \"$flag\";"
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done
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printf '%s\n' "for (int i = 1; i < argc; ++i) {"
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printf '%s\n' " ${var}[${#before[@]} + i] = argv[i];"
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printf '%s\n' "}"
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for ((n = 0; n < ${#after[@]}; n += 1)); do
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flag=$(escapeStringLiteral "${after[n]}")
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printf '%s\n' "${var}[${#before[@]} + argc + $n] = \"$flag\";"
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done
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printf '%s\n' "${var}[${#before[@]} + argc + ${#after[@]}] = NULL;"
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printf '%s\n' "argv = $var;"
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}
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# chdir DIR
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changeDir() {
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local dir
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dir=$(escapeStringLiteral "$1")
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printf '%s' "assert_success(chdir(\"$dir\"));"
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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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assertValidEnvName "$1"
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}
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# suffix ENV SEP VAL
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setEnvSuffix() {
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local env sep val
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env=$(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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assertValidEnvName "$1"
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}
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# setEnv KEY VALUE
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setEnv() {
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local key value
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key=$(escapeStringLiteral "$1")
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value=$(escapeStringLiteral "$2")
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printf '%s' "putenv(\"$key=$value\");"
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assertValidEnvName "$1"
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}
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# setDefaultEnv KEY VALUE
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setDefaultEnv() {
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local key value
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key=$(escapeStringLiteral "$1")
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value=$(escapeStringLiteral "$2")
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printf '%s' "assert_success(setenv(\"$key\", \"$value\", 0));"
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assertValidEnvName "$1"
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}
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# unsetEnv KEY
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unsetEnv() {
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local key
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key=$(escapeStringLiteral "$1")
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printf '%s' "assert_success(unsetenv(\"$key\"));"
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assertValidEnvName "$1"
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}
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# Makes it safe to insert STRING within quotes in a C String Literal.
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# escapeStringLiteral STRING
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escapeStringLiteral() {
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local result
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result=${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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# Indents every non-empty line by 4 spaces. To avoid trailing whitespace, we don't indent empty lines
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# indent4 TEXT_BLOCK
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indent4() {
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printf '%s' "$1" | awk '{ if ($0 != "") { print " "$0 } else { print $0 }}'
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}
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assertValidEnvName() {
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case "$1" in
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*=*) printf '\n%s\n' "#error Illegal environment variable name \`$1\` (cannot contain \`=\`)";;
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"") printf '\n%s\n' "#error Environment variable name can't be empty.";;
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esac
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}
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setSepSurroundCheck() {
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printf '%s' "\
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int is_surrounded_by_sep(char *env, char *ptr, unsigned long len, char *sep) {
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unsigned long sep_len = strlen(sep);
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// Check left side (if not at start)
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if (env != ptr) {
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if (ptr - env < sep_len)
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return 0;
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if (strncmp(sep, ptr - sep_len, sep_len) != 0) {
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return 0;
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}
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}
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// Check right side (if not at end)
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char *end_ptr = ptr + len;
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if (*end_ptr != '\0') {
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if (strncmp(sep, ptr + len, sep_len) != 0) {
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return 0;
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}
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}
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return 1;
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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 *prefix) {
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char *existing_env = getenv(env);
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if (existing_env) {
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char *val;
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char *existing_prefix = strstr(existing_env, prefix);
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unsigned long prefix_len = strlen(prefix);
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// If the prefix already exists, remove the original
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if (existing_prefix && is_surrounded_by_sep(existing_env, existing_prefix, prefix_len, sep)) {
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if (existing_env == existing_prefix) {
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return;
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}
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unsigned long sep_len = strlen(sep);
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int n_before = existing_prefix - existing_env - sep_len;
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assert_success(asprintf(&val, \"%s%s%.*s%s\", prefix, sep,
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n_before, existing_env,
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existing_prefix + prefix_len));
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} else {
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assert_success(asprintf(&val, \"%s%s%s\", prefix, sep, existing_env));
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}
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assert_success(setenv(env, val, 1));
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free(val);
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} else {
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assert_success(setenv(env, prefix, 1));
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}
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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 *suffix) {
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char *existing_env = getenv(env);
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if (existing_env) {
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char *val;
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char *existing_suffix = strstr(existing_env, suffix);
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unsigned long suffix_len = strlen(suffix);
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// If the suffix already exists, remove the original
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if (existing_suffix && is_surrounded_by_sep(existing_env, existing_suffix, suffix_len, sep)) {
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char *end_ptr = existing_suffix + suffix_len;
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if (*end_ptr == '\0') {
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return;
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}
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unsigned long sep_len = strlen(sep);
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int n_before = existing_suffix - existing_env;
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assert_success(asprintf(&val, \"%.*s%s%s%s\",
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n_before, existing_env,
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existing_suffix + suffix_len + sep_len,
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sep, suffix));
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} else {
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assert_success(asprintf(&val, \"%s%s%s\", existing_env, sep, suffix));
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}
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assert_success(setenv(env, val, 1));
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free(val);
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} else {
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assert_success(setenv(env, suffix, 1));
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}
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}
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"
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}
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resolveArgv0Fn() {
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printf '%s' "\
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char *resolve_argv0(char *argv0) {
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if (strchr(argv0, '/') != NULL) {
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return argv0;
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}
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char *path = getenv(\"PATH\");
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if (path == NULL) {
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return argv0;
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}
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char *path_copy = strdup(path);
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if (path_copy == NULL) {
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return argv0;
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}
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char *dir = strtok(path_copy, \":\");
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while (dir != NULL) {
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char *candidate = malloc(strlen(dir) + strlen(argv0) + 2);
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if (candidate == NULL) {
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free(path_copy);
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return argv0;
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}
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sprintf(candidate, \"%s/%s\", dir, argv0);
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if (access(candidate, X_OK) == 0) {
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free(path_copy);
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return candidate;
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}
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free(candidate);
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dir = strtok(NULL, \":\");
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}
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free(path_copy);
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return argv0;
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}
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"
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}
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# Embed a C string which shows up as readable text in the compiled binary wrapper,
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# giving instructions for recreating the wrapper.
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# Keep in sync with makeBinaryWrapper.extractCmd
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docstring() {
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printf '%s' "const char * DOCSTRING = \"$(escapeStringLiteral "
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# ------------------------------------------------------------------------------------
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# The C-code for this binary wrapper has been generated using the following command:
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makeCWrapper $(formatArgs "$@")
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# (Use \`nix-shell -p makeBinaryWrapper\` to get access to makeCWrapper in your shell)
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# ------------------------------------------------------------------------------------
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")\";"
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}
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# formatArgs EXECUTABLE ARGS
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formatArgs() {
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printf '%s' "${1@Q}"
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shift
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while [ $# -gt 0 ]; do
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case "$1" in
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--set)
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formatArgsLine 2 "$@"
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shift 2
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|
;;
|
|
--set-default)
|
|
formatArgsLine 2 "$@"
|
|
shift 2
|
|
;;
|
|
--unset)
|
|
formatArgsLine 1 "$@"
|
|
shift 1
|
|
;;
|
|
--prefix)
|
|
formatArgsLine 3 "$@"
|
|
shift 3
|
|
;;
|
|
--suffix)
|
|
formatArgsLine 3 "$@"
|
|
shift 3
|
|
;;
|
|
--chdir)
|
|
formatArgsLine 1 "$@"
|
|
shift 1
|
|
;;
|
|
--add-flag)
|
|
formatArgsLine 1 "$@"
|
|
shift 1
|
|
;;
|
|
--append-flag)
|
|
formatArgsLine 1 "$@"
|
|
shift 1
|
|
;;
|
|
--add-flags)
|
|
formatArgsLine 1 "$@"
|
|
shift 1
|
|
;;
|
|
--append-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
|
|
}
|