nixpkgs/pkgs/build-support/setup-hooks/patch-shebangs.sh

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# This setup hook causes the fixup phase to rewrite all script
# interpreter file names (`#! /path') to paths found in $PATH. E.g.,
# /bin/sh will be rewritten to /nix/store/<hash>-some-bash/bin/sh.
# /usr/bin/env gets special treatment so that ".../bin/env python" is
# rewritten to /nix/store/<hash>/bin/python. Interpreters that are
# already in the store are left untouched.
# A script file must be marked as executable, otherwise it will not be
# considered.
fixupOutputHooks+=(patchShebangsAuto)
# Run patch shebangs on a directory or file.
# Can take multiple paths as arguments.
# patchShebangs [--build | --host | --update] [--] PATH...
# Flags:
# --build : Lookup commands available at build-time
# --host : Lookup commands available at runtime
# --update : Update shebang paths that are in Nix store
# Example use cases,
# $ patchShebangs --host /nix/store/...-hello-1.0/bin
# $ patchShebangs --build configure
patchShebangs() {
local pathName
local update
while [[ $# -gt 0 ]]; do
case "$1" in
--host)
pathName=HOST_PATH
shift
;;
--build)
pathName=PATH
shift
;;
--update)
update=true
shift
;;
--)
shift
break
;;
-*|--*)
echo "Unknown option $1 supplied to patchShebangs" >&2
return 1
;;
*)
break
;;
esac
done
echo "patching script interpreter paths in $@"
local f
local oldPath
local newPath
local arg0
local args
local oldInterpreterLine
local newInterpreterLine
if [[ $# -eq 0 ]]; then
echo "No arguments supplied to patchShebangs" >&2
return 0
fi
local f
while IFS= read -r -d $'\0' f; do
isScript "$f" || continue
read -r oldInterpreterLine < "$f"
read -r oldPath arg0 args <<< "${oldInterpreterLine:2}"
if [[ -z "${pathName:-}" ]]; then
if [[ -n $strictDeps && $f == "$NIX_STORE"* ]]; then
pathName=HOST_PATH
else
pathName=PATH
fi
fi
if [[ "$oldPath" == *"/bin/env" ]]; then
if [[ $arg0 == "-S" ]]; then
arg0=${args%% *}
args=${args#* }
newPath="$(PATH="${!pathName}" command -v "env" || true)"
args="-S $(PATH="${!pathName}" command -v "$arg0" || true) $args"
# Check for unsupported 'env' functionality:
# - options: something starting with a '-' besides '-S'
# - environment variables: foo=bar
elif [[ $arg0 == "-"* || $arg0 == *"="* ]]; then
echo "$f: unsupported interpreter directive \"$oldInterpreterLine\" (set dontPatchShebangs=1 and handle shebang patching yourself)" >&2
exit 1
else
newPath="$(PATH="${!pathName}" command -v "$arg0" || true)"
fi
else
if [[ -z $oldPath ]]; then
# If no interpreter is specified linux will use /bin/sh. Set
# oldpath="/bin/sh" so that we get /nix/store/.../sh.
oldPath="/bin/sh"
fi
newPath="$(PATH="${!pathName}" command -v "$(basename "$oldPath")" || true)"
args="$arg0 $args"
fi
# Strip trailing whitespace introduced when no arguments are present
newInterpreterLine="$newPath $args"
newInterpreterLine=${newInterpreterLine%${newInterpreterLine##*[![:space:]]}}
if [[ -n "$oldPath" && ( "$update" == true || "${oldPath:0:${#NIX_STORE}}" != "$NIX_STORE" ) ]]; then
if [[ -n "$newPath" && "$newPath" != "$oldPath" ]]; then
echo "$f: interpreter directive changed from \"$oldInterpreterLine\" to \"$newInterpreterLine\""
# escape the escape chars so that sed doesn't interpret them
escapedInterpreterLine=${newInterpreterLine//\\/\\\\}
# Preserve times, see: https://github.com/NixOS/nixpkgs/pull/33281
timestamp=$(stat --printf "%y" "$f")
sed -i -e "1 s|.*|#\!$escapedInterpreterLine|" "$f"
touch --date "$timestamp" "$f"
fi
fi
done < <(find "$@" -type f -perm -0100 -print0)
}
patchShebangsAuto () {
if [[ -z "${dontPatchShebangs-}" && -e "$prefix" ]]; then
# Dev output will end up being run on the build platform. An
# example case of this is sdl2-config. Otherwise, we can just
# use the runtime path (--host).
if [[ "$output" != out && "$output" = "$outputDev" ]]; then
patchShebangs --build "$prefix"
else
patchShebangs --host "$prefix"
fi
fi
}