xnzac · March 29, 2023 08:23
diff --git a/sh.rustup.rs.sh b/sh.rustup.rs.sh
 #!/bin/sh
 # shellcheck shell=dash

 # This is just a little script that can be downloaded from the internet to
 # install rustup. It just does platform detection, downloads the installer
 # and runs it.

 # It runs on Unix shells like {a,ba,da,k,z}sh. It uses the common `local`
 # extension. Note: Most shells limit `local` to 1 var per line, contra bash.

 if [ "$KSH_VERSION" = 'Version JM 93t+ 2010-03-05' ]; then
    # The version of ksh93 that ships with many illumos systems does not
    # support the "local" extension.  Print a message rather than fail in
    # subtle ways later on:
    echo 'rustup does not work with this ksh93 version; please try bash!' >&2
    exit 1
 fi


 set -u

 # If RUSTUP_UPDATE_ROOT is unset or empty, default it.
 RUSTUP_UPDATE_ROOT="${RUSTUP_UPDATE_ROOT:-https://static.rust-lang.org/rustup}"

 #XXX: If you change anything here, please make the same changes in setup_mode.rs
 usage() {
    cat 1>&2 <<EOF
 rustup-init 1.25.2 (8c4dad73d 2023-02-01)
 The installer for rustup

 USAGE:
    rustup-init [FLAGS] [OPTIONS]

 FLAGS:
    -v, --verbose           Enable verbose output
    -q, --quiet             Disable progress output
    -y                      Disable confirmation prompt.
        --no-modify-path    Don't configure the PATH environment variable
    -h, --help              Prints help information
    -V, --version           Prints version information

 OPTIONS:
        --default-host <default-host>              Choose a default host triple
        --default-toolchain <default-toolchain>    Choose a default toolchain to install
        --default-toolchain none                   Do not install any toolchains
        --profile [minimal|default|complete]       Choose a profile
    -c, --component <components>...                Component name to also install
    -t, --target <targets>...                      Target name to also install
 EOF
 }

 main() {
    downloader --check
    need_cmd uname
    need_cmd mktemp
    need_cmd chmod
    need_cmd mkdir
    need_cmd rm
    need_cmd rmdir

    get_architecture || return 1
    local _arch="$RETVAL"
    assert_nz "$_arch" "arch"

    local _ext=""
    case "$_arch" in
        *windows*)
            _ext=".exe"
            ;;
    esac

    local _url="${RUSTUP_UPDATE_ROOT}/dist/${_arch}/rustup-init${_ext}"

    local _dir
    _dir="$(ensure mktemp -d)"
    local _file="${_dir}/rustup-init${_ext}"

    local _ansi_escapes_are_valid=false
    if [ -t 2 ]; then
        if [ "${TERM+set}" = 'set' ]; then
            case "$TERM" in
                xterm*|rxvt*|urxvt*|linux*|vt*)
                    _ansi_escapes_are_valid=true
                ;;
            esac
        fi
    fi

    # check if we have to use /dev/tty to prompt the user
    local need_tty=yes
    for arg in "$@"; do
        case "$arg" in
            --help)
                usage
                exit 0
                ;;
            *)
                OPTIND=1
                if [ "${arg%%--*}" = "" ]; then
                    # Long option (other than --help);
                    # don't attempt to interpret it.
                    continue
                fi
                while getopts :hy sub_arg "$arg"; do
                    case "$sub_arg" in
                        h)
                            usage
                            exit 0
                            ;;
                        y)
                            # user wants to skip the prompt --
                            # we don't need /dev/tty
                            need_tty=no
                            ;;
                        *)
                            ;;
                        esac
                done
                ;;
        esac
    done

    if $_ansi_escapes_are_valid; then
        printf "\33[1minfo:\33[0m downloading installer\n" 1>&2
    else
        printf '%s\n' 'info: downloading installer' 1>&2
    fi

    ensure mkdir -p "$_dir"
    ensure downloader "$_url" "$_file" "$_arch"
    ensure chmod u+x "$_file"
    if [ ! -x "$_file" ]; then
        printf '%s\n' "Cannot execute $_file (likely because of mounting /tmp as noexec)." 1>&2
        printf '%s\n' "Please copy the file to a location where you can execute binaries and run ./rustup-init${_ext}." 1>&2
        exit 1
    fi

    if [ "$need_tty" = "yes" ] && [ ! -t 0 ]; then
        # The installer is going to want to ask for confirmation by
        # reading stdin.  This script was piped into `sh` though and
        # doesn't have stdin to pass to its children. Instead we're going
        # to explicitly connect /dev/tty to the installer's stdin.
        if [ ! -t 1 ]; then
            err "Unable to run interactively. Run with -y to accept defaults, --help for additional options"
        fi

        ignore "$_file" "$@" < /dev/tty
    else
        ignore "$_file" "$@"
    fi

    local _retval=$?

    ignore rm "$_file"
    ignore rmdir "$_dir"

    return "$_retval"
 }

 check_proc() {
    # Check for /proc by looking for the /proc/self/exe link
    # This is only run on Linux
    if ! test -L /proc/self/exe ; then
        err "fatal: Unable to find /proc/self/exe.  Is /proc mounted?  Installation cannot proceed without /proc."
    fi
 }

 get_bitness() {
    need_cmd head
    # Architecture detection without dependencies beyond coreutils.
    # ELF files start out "\x7fELF", and the following byte is
    #   0x01 for 32-bit and
    #   0x02 for 64-bit.
    # The printf builtin on some shells like dash only supports octal
    # escape sequences, so we use those.
    local _current_exe_head
    _current_exe_head=$(head -c 5 /proc/self/exe )
    if [ "$_current_exe_head" = "$(printf '\177ELF\001')" ]; then
        echo 32
    elif [ "$_current_exe_head" = "$(printf '\177ELF\002')" ]; then
        echo 64
    else
        err "unknown platform bitness"
    fi
 }

 is_host_amd64_elf() {
    need_cmd head
    need_cmd tail
    # ELF e_machine detection without dependencies beyond coreutils.
    # Two-byte field at offset 0x12 indicates the CPU,
    # but we're interested in it being 0x3E to indicate amd64, or not that.
    local _current_exe_machine
    _current_exe_machine=$(head -c 19 /proc/self/exe | tail -c 1)
    [ "$_current_exe_machine" = "$(printf '\076')" ]
 }

 get_endianness() {
    local cputype=$1
    local suffix_eb=$2
    local suffix_el=$3

    # detect endianness without od/hexdump, like get_bitness() does.
    need_cmd head
    need_cmd tail

    local _current_exe_endianness
    _current_exe_endianness="$(head -c 6 /proc/self/exe | tail -c 1)"
    if [ "$_current_exe_endianness" = "$(printf '\001')" ]; then
        echo "${cputype}${suffix_el}"
    elif [ "$_current_exe_endianness" = "$(printf '\002')" ]; then
        echo "${cputype}${suffix_eb}"
    else
        err "unknown platform endianness"
    fi
 }

 get_architecture() {
    local _ostype _cputype _bitness _arch _clibtype
    _ostype="$(uname -s)"
    _cputype="$(uname -m)"
    _clibtype="gnu"

    if [ "$_ostype" = Linux ]; then
        if [ "$(uname -o)" = Android ]; then
            _ostype=Android
        fi
        if ldd --version 2>&1 | grep -q 'musl'; then
            _clibtype="musl"
        fi
    fi

    if [ "$_ostype" = Darwin ] && [ "$_cputype" = i386 ]; then
        # Darwin `uname -m` lies
        if sysctl hw.optional.x86_64 | grep -q ': 1'; then
            _cputype=x86_64
        fi
    fi

    if [ "$_ostype" = SunOS ]; then
        # Both Solaris and illumos presently announce as "SunOS" in "uname -s"
        # so use "uname -o" to disambiguate.  We use the full path to the
        # system uname in case the user has coreutils uname first in PATH,
        # which has historically sometimes printed the wrong value here.
        if [ "$(/usr/bin/uname -o)" = illumos ]; then
            _ostype=illumos
        fi

        # illumos systems have multi-arch userlands, and "uname -m" reports the
        # machine hardware name; e.g., "i86pc" on both 32- and 64-bit x86
        # systems.  Check for the native (widest) instruction set on the
        # running kernel:
        if [ "$_cputype" = i86pc ]; then
            _cputype="$(isainfo -n)"
        fi
    fi

    case "$_ostype" in

        Android)
            _ostype=linux-android
            ;;

        Linux)
            check_proc
            _ostype=unknown-linux-$_clibtype
            _bitness=$(get_bitness)
            ;;

        FreeBSD)
            _ostype=unknown-freebsd
            ;;

        NetBSD)
            _ostype=unknown-netbsd
            ;;

        DragonFly)
            _ostype=unknown-dragonfly
            ;;

        Darwin)
            _ostype=apple-darwin
            ;;

        illumos)
            _ostype=unknown-illumos
            ;;

        MINGW* | MSYS* | CYGWIN* | Windows_NT)
            _ostype=pc-windows-gnu
            ;;

        *)
            err "unrecognized OS type: $_ostype"
            ;;

    esac

    case "$_cputype" in

        i386 | i486 | i686 | i786 | x86)
            _cputype=i686
            ;;

        xscale | arm)
            _cputype=arm
            if [ "$_ostype" = "linux-android" ]; then
                _ostype=linux-androideabi
            fi
            ;;

        armv6l)
            _cputype=arm
            if [ "$_ostype" = "linux-android" ]; then
                _ostype=linux-androideabi
            else
                _ostype="${_ostype}eabihf"
            fi
            ;;

        armv7l | armv8l)
            _cputype=armv7
            if [ "$_ostype" = "linux-android" ]; then
                _ostype=linux-androideabi
            else
                _ostype="${_ostype}eabihf"
            fi
            ;;

        aarch64 | arm64)
            _cputype=aarch64
            ;;

        x86_64 | x86-64 | x64 | amd64)
            _cputype=x86_64
            ;;

        mips)
            _cputype=$(get_endianness mips '' el)
            ;;

        mips64)
            if [ "$_bitness" -eq 64 ]; then
                # only n64 ABI is supported for now
                _ostype="${_ostype}abi64"
                _cputype=$(get_endianness mips64 '' el)
            fi
            ;;

        ppc)
            _cputype=powerpc
            ;;

        ppc64)
            _cputype=powerpc64
            ;;

        ppc64le)
            _cputype=powerpc64le
            ;;

        s390x)
            _cputype=s390x
            ;;
        riscv64)
            _cputype=riscv64gc
            ;;
        *)
            err "unknown CPU type: $_cputype"

    esac

    # Detect 64-bit linux with 32-bit userland
    if [ "${_ostype}" = unknown-linux-gnu ] && [ "${_bitness}" -eq 32 ]; then
        case $_cputype in
            x86_64)
                if [ -n "${RUSTUP_CPUTYPE:-}" ]; then
                    _cputype="$RUSTUP_CPUTYPE"
                else {
                    # 32-bit executable for amd64 = x32
                    if is_host_amd64_elf; then {
                         echo "This host is running an x32 userland; as it stands, x32 support is poor," 1>&2
                         echo "and there isn't a native toolchain -- you will have to install" 1>&2
                         echo "multiarch compatibility with i686 and/or amd64, then select one" 1>&2
                         echo "by re-running this script with the RUSTUP_CPUTYPE environment variable" 1>&2
                         echo "set to i686 or x86_64, respectively." 1>&2
                         echo 1>&2
                         echo "You will be able to add an x32 target after installation by running" 1>&2
                         echo "  rustup target add x86_64-unknown-linux-gnux32" 1>&2
                         exit 1
                    }; else
                        _cputype=i686
                    fi
                }; fi
                ;;
            mips64)
                _cputype=$(get_endianness mips '' el)
                ;;
            powerpc64)
                _cputype=powerpc
                ;;
            aarch64)
                _cputype=armv7
                if [ "$_ostype" = "linux-android" ]; then
                    _ostype=linux-androideabi
                else
                    _ostype="${_ostype}eabihf"
                fi
                ;;
            riscv64gc)
                err "riscv64 with 32-bit userland unsupported"
                ;;
        esac
    fi

    # Detect armv7 but without the CPU features Rust needs in that build,
    # and fall back to arm.
    # See https://github.com/rust-lang/rustup.rs/issues/587.
    if [ "$_ostype" = "unknown-linux-gnueabihf" ] && [ "$_cputype" = armv7 ]; then
        if ensure grep '^Features' /proc/cpuinfo | grep -q -v neon; then
            # At least one processor does not have NEON.
            _cputype=arm
        fi
    fi

    _arch="${_cputype}-${_ostype}"

    RETVAL="$_arch"
 }

 say() {
    printf 'rustup: %s\n' "$1"
 }

 err() {
    say "$1" >&2
    exit 1
 }

 need_cmd() {
    if ! check_cmd "$1"; then
        err "need '$1' (command not found)"
    fi
 }

 check_cmd() {
    command -v "$1" > /dev/null 2>&1
 }

 assert_nz() {
    if [ -z "$1" ]; then err "assert_nz $2"; fi
 }

 # Run a command that should never fail. If the command fails execution
 # will immediately terminate with an error showing the failing
 # command.
 ensure() {
    if ! "$@"; then err "command failed: $*"; fi
 }

 # This is just for indicating that commands' results are being
 # intentionally ignored. Usually, because it's being executed
 # as part of error handling.
 ignore() {
    "$@"
 }

 # This wraps curl or wget. Try curl first, if not installed,
 # use wget instead.
 downloader() {
    local _dld
    local _ciphersuites
    local _err
    local _status
    local _retry
    if check_cmd curl; then
        _dld=curl
    elif check_cmd wget; then
        _dld=wget
    else
        _dld='curl or wget' # to be used in error message of need_cmd
    fi

    if [ "$1" = --check ]; then
        need_cmd "$_dld"
    elif [ "$_dld" = curl ]; then
        check_curl_for_retry_support
        _retry="$RETVAL"
        get_ciphersuites_for_curl
        _ciphersuites="$RETVAL"
        if [ -n "$_ciphersuites" ]; then
            _err=$(curl $_retry --proto '=https' --tlsv1.2 --ciphers "$_ciphersuites" --silent --show-error --fail --location "$1" --output "$2" 2>&1)
            _status=$?
        else
            echo "Warning: Not enforcing strong cipher suites for TLS, this is potentially less secure"
            if ! check_help_for "$3" curl --proto --tlsv1.2; then
                echo "Warning: Not enforcing TLS v1.2, this is potentially less secure"
                _err=$(curl $_retry --silent --show-error --fail --location "$1" --output "$2" 2>&1)
                _status=$?
            else
                _err=$(curl $_retry --proto '=https' --tlsv1.2 --silent --show-error --fail --location "$1" --output "$2" 2>&1)
                _status=$?
            fi
        fi
        if [ -n "$_err" ]; then
            echo "$_err" >&2
            if echo "$_err" | grep -q 404$; then
                err "installer for platform '$3' not found, this may be unsupported"
            fi
        fi
        return $_status
    elif [ "$_dld" = wget ]; then
        if [ "$(wget -V 2>&1|head -2|tail -1|cut -f1 -d" ")" = "BusyBox" ]; then
            echo "Warning: using the BusyBox version of wget.  Not enforcing strong cipher suites for TLS or TLS v1.2, this is potentially less secure"
            _err=$(wget "$1" -O "$2" 2>&1)
            _status=$?
        else
            get_ciphersuites_for_wget
            _ciphersuites="$RETVAL"
            if [ -n "$_ciphersuites" ]; then
                _err=$(wget --https-only --secure-protocol=TLSv1_2 --ciphers "$_ciphersuites" "$1" -O "$2" 2>&1)
                _status=$?
            else
                echo "Warning: Not enforcing strong cipher suites for TLS, this is potentially less secure"
                if ! check_help_for "$3" wget --https-only --secure-protocol; then
                    echo "Warning: Not enforcing TLS v1.2, this is potentially less secure"
                    _err=$(wget "$1" -O "$2" 2>&1)
                    _status=$?
                else
                    _err=$(wget --https-only --secure-protocol=TLSv1_2 "$1" -O "$2" 2>&1)
                    _status=$?
                fi
            fi
        fi
        if [ -n "$_err" ]; then
            echo "$_err" >&2
            if echo "$_err" | grep -q ' 404 Not Found$'; then
                err "installer for platform '$3' not found, this may be unsupported"
            fi
        fi
        return $_status
    else
        err "Unknown downloader"   # should not reach here
    fi
 }

 check_help_for() {
    local _arch
    local _cmd
    local _arg
    _arch="$1"
    shift
    _cmd="$1"
    shift

    local _category
    if "$_cmd" --help | grep -q 'For all options use the manual or "--help all".'; then
      _category="all"
    else
      _category=""
    fi

    case "$_arch" in

        *darwin*)
        if check_cmd sw_vers; then
            case $(sw_vers -productVersion) in
                10.*)
                    # If we're running on macOS, older than 10.13, then we always
                    # fail to find these options to force fallback
                    if [ "$(sw_vers -productVersion | cut -d. -f2)" -lt 13 ]; then
                        # Older than 10.13
                        echo "Warning: Detected macOS platform older than 10.13"
                        return 1
                    fi
                    ;;
                11.*)
                    # We assume Big Sur will be OK for now
                    ;;
                *)
                    # Unknown product version, warn and continue
                    echo "Warning: Detected unknown macOS major version: $(sw_vers -productVersion)"
                    echo "Warning TLS capabilities detection may fail"
                    ;;
            esac
        fi
        ;;

    esac

    for _arg in "$@"; do
        if ! "$_cmd" --help "$_category" | grep -q -- "$_arg"; then
            return 1
        fi
    done

    true # not strictly needed
 }

 # Check if curl supports the --retry flag, then pass it to the curl invocation.
 check_curl_for_retry_support() {
  local _retry_supported=""
  # "unspecified" is for arch, allows for possibility old OS using macports, homebrew, etc.
  if check_help_for "notspecified" "curl" "--retry"; then
    _retry_supported="--retry 3"
  fi

  RETVAL="$_retry_supported"

 }

 # Return cipher suite string specified by user, otherwise return strong TLS 1.2-1.3 cipher suites
 # if support by local tools is detected. Detection currently supports these curl backends:
 # GnuTLS and OpenSSL (possibly also LibreSSL and BoringSSL). Return value can be empty.
 get_ciphersuites_for_curl() {
    if [ -n "${RUSTUP_TLS_CIPHERSUITES-}" ]; then
        # user specified custom cipher suites, assume they know what they're doing
        RETVAL="$RUSTUP_TLS_CIPHERSUITES"
        return
    fi

    local _openssl_syntax="no"
    local _gnutls_syntax="no"
    local _backend_supported="yes"
    if curl -V | grep -q ' OpenSSL/'; then
        _openssl_syntax="yes"
    elif curl -V | grep -iq ' LibreSSL/'; then
        _openssl_syntax="yes"
    elif curl -V | grep -iq ' BoringSSL/'; then
        _openssl_syntax="yes"
    elif curl -V | grep -iq ' GnuTLS/'; then
        _gnutls_syntax="yes"
    else
        _backend_supported="no"
    fi

    local _args_supported="no"
    if [ "$_backend_supported" = "yes" ]; then
        # "unspecified" is for arch, allows for possibility old OS using macports, homebrew, etc.
        if check_help_for "notspecified" "curl" "--tlsv1.2" "--ciphers" "--proto"; then
            _args_supported="yes"
        fi
    fi

    local _cs=""
    if [ "$_args_supported" = "yes" ]; then
        if [ "$_openssl_syntax" = "yes" ]; then
            _cs=$(get_strong_ciphersuites_for "openssl")
        elif [ "$_gnutls_syntax" = "yes" ]; then
            _cs=$(get_strong_ciphersuites_for "gnutls")
        fi
    fi

    RETVAL="$_cs"
 }

 # Return cipher suite string specified by user, otherwise return strong TLS 1.2-1.3 cipher suites
 # if support by local tools is detected. Detection currently supports these wget backends:
 # GnuTLS and OpenSSL (possibly also LibreSSL and BoringSSL). Return value can be empty.
 get_ciphersuites_for_wget() {
    if [ -n "${RUSTUP_TLS_CIPHERSUITES-}" ]; then
        # user specified custom cipher suites, assume they know what they're doing
        RETVAL="$RUSTUP_TLS_CIPHERSUITES"
        return
    fi

    local _cs=""
    if wget -V | grep -q '\-DHAVE_LIBSSL'; then
        # "unspecified" is for arch, allows for possibility old OS using macports, homebrew, etc.
        if check_help_for "notspecified" "wget" "TLSv1_2" "--ciphers" "--https-only" "--secure-protocol"; then
            _cs=$(get_strong_ciphersuites_for "openssl")
        fi
    elif wget -V | grep -q '\-DHAVE_LIBGNUTLS'; then
        # "unspecified" is for arch, allows for possibility old OS using macports, homebrew, etc.
        if check_help_for "notspecified" "wget" "TLSv1_2" "--ciphers" "--https-only" "--secure-protocol"; then
            _cs=$(get_strong_ciphersuites_for "gnutls")
        fi
    fi

    RETVAL="$_cs"
 }

 # Return strong TLS 1.2-1.3 cipher suites in OpenSSL or GnuTLS syntax. TLS 1.2
 # excludes non-ECDHE and non-AEAD cipher suites. DHE is excluded due to bad
 # DH params often found on servers (see RFC 7919). Sequence matches or is
 # similar to Firefox 68 ESR with weak cipher suites disabled via about:config.
 # $1 must be openssl or gnutls.
 get_strong_ciphersuites_for() {
    if [ "$1" = "openssl" ]; then
        # OpenSSL is forgiving of unknown values, no problems with TLS 1.3 values on versions that don't support it yet.
        echo "TLS_AES_128_GCM_SHA256:TLS_CHACHA20_POLY1305_SHA256:TLS_AES_256_GCM_SHA384:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384"
    elif [ "$1" = "gnutls" ]; then
        # GnuTLS isn't forgiving of unknown values, so this may require a GnuTLS version that supports TLS 1.3 even if wget doesn't.
        # Begin with SECURE128 (and higher) then remove/add to build cipher suites. Produces same 9 cipher suites as OpenSSL but in slightly different order.
        echo "SECURE128:-VERS-SSL3.0:-VERS-TLS1.0:-VERS-TLS1.1:-VERS-DTLS-ALL:-CIPHER-ALL:-MAC-ALL:-KX-ALL:+AEAD:+ECDHE-ECDSA:+ECDHE-RSA:+AES-128-GCM:+CHACHA20-POLY1305:+AES-256-GCM"
    fi
 }

 main "$@" || exit 1
	#!/bin/sh
	# shellcheck shell=dash

	# This is just a little script that can be downloaded from the internet to
	# install rustup. It just does platform detection, downloads the installer
	# and runs it.

	# It runs on Unix shells like {a,ba,da,k,z}sh. It uses the common `local`
	# extension. Note: Most shells limit `local` to 1 var per line, contra bash.

	if [ "$KSH_VERSION" = 'Version JM 93t+ 2010-03-05' ]; then
	# The version of ksh93 that ships with many illumos systems does not
	# support the "local" extension. Print a message rather than fail in
	# subtle ways later on:
	echo 'rustup does not work with this ksh93 version; please try bash!' >&2
	exit 1
	fi


	set -u

	# If RUSTUP_UPDATE_ROOT is unset or empty, default it.
	RUSTUP_UPDATE_ROOT="${RUSTUP_UPDATE_ROOT:-https://static.rust-lang.org/rustup}"

	#XXX: If you change anything here, please make the same changes in setup_mode.rs
	usage() {
	cat 1>&2 <<EOF
	rustup-init 1.25.2 (8c4dad73d 2023-02-01)
	The installer for rustup

	USAGE:
	rustup-init [FLAGS] [OPTIONS]

	FLAGS:
	-v, --verbose Enable verbose output
	-q, --quiet Disable progress output
	-y Disable confirmation prompt.
	--no-modify-path Don't configure the PATH environment variable
	-h, --help Prints help information
	-V, --version Prints version information

	OPTIONS:
	--default-host <default-host> Choose a default host triple
	--default-toolchain <default-toolchain> Choose a default toolchain to install
	--default-toolchain none Do not install any toolchains
	--profile [minimal\|default\|complete] Choose a profile
	-c, --component <components>... Component name to also install
	-t, --target <targets>... Target name to also install
	EOF
	}

	main() {
	downloader --check
	need_cmd uname
	need_cmd mktemp
	need_cmd chmod
	need_cmd mkdir
	need_cmd rm
	need_cmd rmdir

	get_architecture \|\| return 1
	local _arch="$RETVAL"
	assert_nz "$_arch" "arch"

	local _ext=""
	case "$_arch" in
	windows)
	_ext=".exe"
	;;
	esac

	local _url="${RUSTUP_UPDATE_ROOT}/dist/${_arch}/rustup-init${_ext}"

	local _dir
	_dir="$(ensure mktemp -d)"
	local _file="${_dir}/rustup-init${_ext}"

	local _ansi_escapes_are_valid=false
	if [ -t 2 ]; then
	if [ "${TERM+set}" = 'set' ]; then
	case "$TERM" in
	xterm\|rxvt\|urxvt\|linux\|vt*)
	_ansi_escapes_are_valid=true
	;;
	esac
	fi
	fi

	# check if we have to use /dev/tty to prompt the user
	local need_tty=yes
	for arg in "$@"; do
	case "$arg" in
	--help)
	usage
	exit 0
	;;
	*)
	OPTIND=1
	if [ "${arg%%--*}" = "" ]; then
	# Long option (other than --help);
	# don't attempt to interpret it.
	continue
	fi
	while getopts :hy sub_arg "$arg"; do
	case "$sub_arg" in
	h)
	usage
	exit 0
	;;
	y)
	# user wants to skip the prompt --
	# we don't need /dev/tty
	need_tty=no
	;;
	*)
	;;
	esac
	done
	;;
	esac
	done

	if $_ansi_escapes_are_valid; then
	printf "\33[1minfo:\33[0m downloading installer\n" 1>&2
	else
	printf '%s\n' 'info: downloading installer' 1>&2
	fi

	ensure mkdir -p "$_dir"
	ensure downloader "$_url" "$_file" "$_arch"
	ensure chmod u+x "$_file"
	if [ ! -x "$_file" ]; then
	printf '%s\n' "Cannot execute $_file (likely because of mounting /tmp as noexec)." 1>&2
	printf '%s\n' "Please copy the file to a location where you can execute binaries and run ./rustup-init${_ext}." 1>&2
	exit 1
	fi

	if [ "$need_tty" = "yes" ] && [ ! -t 0 ]; then
	# The installer is going to want to ask for confirmation by
	# reading stdin. This script was piped into `sh` though and
	# doesn't have stdin to pass to its children. Instead we're going
	# to explicitly connect /dev/tty to the installer's stdin.
	if [ ! -t 1 ]; then
	err "Unable to run interactively. Run with -y to accept defaults, --help for additional options"
	fi

	ignore "$_file" "$@" < /dev/tty
	else
	ignore "$_file" "$@"
	fi

	local _retval=$?

	ignore rm "$_file"
	ignore rmdir "$_dir"

	return "$_retval"
	}

	check_proc() {
	# Check for /proc by looking for the /proc/self/exe link
	# This is only run on Linux
	if ! test -L /proc/self/exe ; then
	err "fatal: Unable to find /proc/self/exe. Is /proc mounted? Installation cannot proceed without /proc."
	fi
	}

	get_bitness() {
	need_cmd head
	# Architecture detection without dependencies beyond coreutils.
	# ELF files start out "\x7fELF", and the following byte is
	# 0x01 for 32-bit and
	# 0x02 for 64-bit.
	# The printf builtin on some shells like dash only supports octal
	# escape sequences, so we use those.
	local _current_exe_head
	_current_exe_head=$(head -c 5 /proc/self/exe )
	if [ "$_current_exe_head" = "$(printf '\177ELF\001')" ]; then
	echo 32
	elif [ "$_current_exe_head" = "$(printf '\177ELF\002')" ]; then
	echo 64
	else
	err "unknown platform bitness"
	fi
	}

	is_host_amd64_elf() {
	need_cmd head
	need_cmd tail
	# ELF e_machine detection without dependencies beyond coreutils.
	# Two-byte field at offset 0x12 indicates the CPU,
	# but we're interested in it being 0x3E to indicate amd64, or not that.
	local _current_exe_machine
	_current_exe_machine=$(head -c 19 /proc/self/exe \| tail -c 1)
	[ "$_current_exe_machine" = "$(printf '\076')" ]
	}

	get_endianness() {
	local cputype=$1
	local suffix_eb=$2
	local suffix_el=$3

	# detect endianness without od/hexdump, like get_bitness() does.
	need_cmd head
	need_cmd tail

	local _current_exe_endianness
	_current_exe_endianness="$(head -c 6 /proc/self/exe \| tail -c 1)"
	if [ "$_current_exe_endianness" = "$(printf '\001')" ]; then
	echo "${cputype}${suffix_el}"
	elif [ "$_current_exe_endianness" = "$(printf '\002')" ]; then
	echo "${cputype}${suffix_eb}"
	else
	err "unknown platform endianness"
	fi
	}

	get_architecture() {
	local _ostype _cputype _bitness _arch _clibtype
	_ostype="$(uname -s)"
	_cputype="$(uname -m)"
	_clibtype="gnu"

	if [ "$_ostype" = Linux ]; then
	if [ "$(uname -o)" = Android ]; then
	_ostype=Android
	fi
	if ldd --version 2>&1 \| grep -q 'musl'; then
	_clibtype="musl"
	fi
	fi

	if [ "$_ostype" = Darwin ] && [ "$_cputype" = i386 ]; then
	# Darwin `uname -m` lies
	if sysctl hw.optional.x86_64 \| grep -q ': 1'; then
	_cputype=x86_64
	fi
	fi

	if [ "$_ostype" = SunOS ]; then
	# Both Solaris and illumos presently announce as "SunOS" in "uname -s"
	# so use "uname -o" to disambiguate. We use the full path to the
	# system uname in case the user has coreutils uname first in PATH,
	# which has historically sometimes printed the wrong value here.
	if [ "$(/usr/bin/uname -o)" = illumos ]; then
	_ostype=illumos
	fi

	# illumos systems have multi-arch userlands, and "uname -m" reports the
	# machine hardware name; e.g., "i86pc" on both 32- and 64-bit x86
	# systems. Check for the native (widest) instruction set on the
	# running kernel:
	if [ "$_cputype" = i86pc ]; then
	_cputype="$(isainfo -n)"
	fi
	fi

	case "$_ostype" in

	Android)
	_ostype=linux-android
	;;

	Linux)
	check_proc
	_ostype=unknown-linux-$_clibtype
	_bitness=$(get_bitness)
	;;

	FreeBSD)
	_ostype=unknown-freebsd
	;;

	NetBSD)
	_ostype=unknown-netbsd
	;;

	DragonFly)
	_ostype=unknown-dragonfly
	;;

	Darwin)
	_ostype=apple-darwin
	;;

	illumos)
	_ostype=unknown-illumos
	;;

	MINGW* \| MSYS* \| CYGWIN* \| Windows_NT)
	_ostype=pc-windows-gnu
	;;

	*)
	err "unrecognized OS type: $_ostype"
	;;

	esac

	case "$_cputype" in

	i386 \| i486 \| i686 \| i786 \| x86)
	_cputype=i686
	;;

	xscale \| arm)
	_cputype=arm
	if [ "$_ostype" = "linux-android" ]; then
	_ostype=linux-androideabi
	fi
	;;

	armv6l)
	_cputype=arm
	if [ "$_ostype" = "linux-android" ]; then
	_ostype=linux-androideabi
	else
	_ostype="${_ostype}eabihf"
	fi
	;;

	armv7l \| armv8l)
	_cputype=armv7
	if [ "$_ostype" = "linux-android" ]; then
	_ostype=linux-androideabi
	else
	_ostype="${_ostype}eabihf"
	fi
	;;

	aarch64 \| arm64)
	_cputype=aarch64
	;;

	x86_64 \| x86-64 \| x64 \| amd64)
	_cputype=x86_64
	;;

	mips)
	_cputype=$(get_endianness mips '' el)
	;;

	mips64)
	if [ "$_bitness" -eq 64 ]; then
	# only n64 ABI is supported for now
	_ostype="${_ostype}abi64"
	_cputype=$(get_endianness mips64 '' el)
	fi
	;;

	ppc)
	_cputype=powerpc
	;;

	ppc64)
	_cputype=powerpc64
	;;

	ppc64le)
	_cputype=powerpc64le
	;;

	s390x)
	_cputype=s390x
	;;
	riscv64)
	_cputype=riscv64gc
	;;
	*)
	err "unknown CPU type: $_cputype"

	esac

	# Detect 64-bit linux with 32-bit userland
	if [ "${_ostype}" = unknown-linux-gnu ] && [ "${_bitness}" -eq 32 ]; then
	case $_cputype in
	x86_64)
	if [ -n "${RUSTUP_CPUTYPE:-}" ]; then
	_cputype="$RUSTUP_CPUTYPE"
	else {
	# 32-bit executable for amd64 = x32
	if is_host_amd64_elf; then {
	echo "This host is running an x32 userland; as it stands, x32 support is poor," 1>&2
	echo "and there isn't a native toolchain -- you will have to install" 1>&2
	echo "multiarch compatibility with i686 and/or amd64, then select one" 1>&2
	echo "by re-running this script with the RUSTUP_CPUTYPE environment variable" 1>&2
	echo "set to i686 or x86_64, respectively." 1>&2
	echo 1>&2
	echo "You will be able to add an x32 target after installation by running" 1>&2
	echo " rustup target add x86_64-unknown-linux-gnux32" 1>&2
	exit 1
	}; else
	_cputype=i686
	fi
	}; fi
	;;
	mips64)
	_cputype=$(get_endianness mips '' el)
	;;
	powerpc64)
	_cputype=powerpc
	;;
	aarch64)
	_cputype=armv7
	if [ "$_ostype" = "linux-android" ]; then
	_ostype=linux-androideabi
	else
	_ostype="${_ostype}eabihf"
	fi
	;;
	riscv64gc)
	err "riscv64 with 32-bit userland unsupported"
	;;
	esac
	fi

	# Detect armv7 but without the CPU features Rust needs in that build,
	# and fall back to arm.
	# See https://github.com/rust-lang/rustup.rs/issues/587.
	if [ "$_ostype" = "unknown-linux-gnueabihf" ] && [ "$_cputype" = armv7 ]; then
	if ensure grep '^Features' /proc/cpuinfo \| grep -q -v neon; then
	# At least one processor does not have NEON.
	_cputype=arm
	fi
	fi

	_arch="${_cputype}-${_ostype}"

	RETVAL="$_arch"
	}

	say() {
	printf 'rustup: %s\n' "$1"
	}

	err() {
	say "$1" >&2
	exit 1
	}

	need_cmd() {
	if ! check_cmd "$1"; then
	err "need '$1' (command not found)"
	fi
	}

	check_cmd() {
	command -v "$1" > /dev/null 2>&1
	}

	assert_nz() {
	if [ -z "$1" ]; then err "assert_nz $2"; fi
	}

	# Run a command that should never fail. If the command fails execution
	# will immediately terminate with an error showing the failing
	# command.
	ensure() {
	if ! "$@"; then err "command failed: $*"; fi
	}

	# This is just for indicating that commands' results are being
	# intentionally ignored. Usually, because it's being executed
	# as part of error handling.
	ignore() {
	"$@"
	}

	# This wraps curl or wget. Try curl first, if not installed,
	# use wget instead.
	downloader() {
	local _dld
	local _ciphersuites
	local _err
	local _status
	local _retry
	if check_cmd curl; then
	_dld=curl
	elif check_cmd wget; then
	_dld=wget
	else
	_dld='curl or wget' # to be used in error message of need_cmd
	fi

	if [ "$1" = --check ]; then
	need_cmd "$_dld"
	elif [ "$_dld" = curl ]; then
	check_curl_for_retry_support
	_retry="$RETVAL"
	get_ciphersuites_for_curl
	_ciphersuites="$RETVAL"
	if [ -n "$_ciphersuites" ]; then
	_err=$(curl $_retry --proto '=https' --tlsv1.2 --ciphers "$_ciphersuites" --silent --show-error --fail --location "$1" --output "$2" 2>&1)
	_status=$?
	else
	echo "Warning: Not enforcing strong cipher suites for TLS, this is potentially less secure"
	if ! check_help_for "$3" curl --proto --tlsv1.2; then
	echo "Warning: Not enforcing TLS v1.2, this is potentially less secure"
	_err=$(curl $_retry --silent --show-error --fail --location "$1" --output "$2" 2>&1)
	_status=$?
	else
	_err=$(curl $_retry --proto '=https' --tlsv1.2 --silent --show-error --fail --location "$1" --output "$2" 2>&1)
	_status=$?
	fi
	fi
	if [ -n "$_err" ]; then
	echo "$_err" >&2
	if echo "$_err" \| grep -q 404$; then
	err "installer for platform '$3' not found, this may be unsupported"
	fi
	fi
	return $_status
	elif [ "$_dld" = wget ]; then
	if [ "$(wget -V 2>&1\|head -2\|tail -1\|cut -f1 -d" ")" = "BusyBox" ]; then
	echo "Warning: using the BusyBox version of wget. Not enforcing strong cipher suites for TLS or TLS v1.2, this is potentially less secure"
	_err=$(wget "$1" -O "$2" 2>&1)
	_status=$?
	else
	get_ciphersuites_for_wget
	_ciphersuites="$RETVAL"
	if [ -n "$_ciphersuites" ]; then
	_err=$(wget --https-only --secure-protocol=TLSv1_2 --ciphers "$_ciphersuites" "$1" -O "$2" 2>&1)
	_status=$?
	else
	echo "Warning: Not enforcing strong cipher suites for TLS, this is potentially less secure"
	if ! check_help_for "$3" wget --https-only --secure-protocol; then
	echo "Warning: Not enforcing TLS v1.2, this is potentially less secure"
	_err=$(wget "$1" -O "$2" 2>&1)
	_status=$?
	else
	_err=$(wget --https-only --secure-protocol=TLSv1_2 "$1" -O "$2" 2>&1)
	_status=$?
	fi
	fi
	fi
	if [ -n "$_err" ]; then
	echo "$_err" >&2
	if echo "$_err" \| grep -q ' 404 Not Found$'; then
	err "installer for platform '$3' not found, this may be unsupported"
	fi
	fi
	return $_status
	else
	err "Unknown downloader" # should not reach here
	fi
	}

	check_help_for() {
	local _arch
	local _cmd
	local _arg
	_arch="$1"
	shift
	_cmd="$1"
	shift

	local _category
	if "$_cmd" --help \| grep -q 'For all options use the manual or "--help all".'; then
	_category="all"
	else
	_category=""
	fi

	case "$_arch" in

	darwin)
	if check_cmd sw_vers; then
	case $(sw_vers -productVersion) in
	10.*)
	# If we're running on macOS, older than 10.13, then we always
	# fail to find these options to force fallback
	if [ "$(sw_vers -productVersion \| cut -d. -f2)" -lt 13 ]; then
	# Older than 10.13
	echo "Warning: Detected macOS platform older than 10.13"
	return 1
	fi
	;;
	11.*)
	# We assume Big Sur will be OK for now
	;;
	*)
	# Unknown product version, warn and continue
	echo "Warning: Detected unknown macOS major version: $(sw_vers -productVersion)"
	echo "Warning TLS capabilities detection may fail"
	;;
	esac
	fi
	;;

	esac

	for _arg in "$@"; do
	if ! "$_cmd" --help "$_category" \| grep -q -- "$_arg"; then
	return 1
	fi
	done

	true # not strictly needed
	}

	# Check if curl supports the --retry flag, then pass it to the curl invocation.
	check_curl_for_retry_support() {
	local _retry_supported=""
	# "unspecified" is for arch, allows for possibility old OS using macports, homebrew, etc.
	if check_help_for "notspecified" "curl" "--retry"; then
	_retry_supported="--retry 3"
	fi

	RETVAL="$_retry_supported"

	}

	# Return cipher suite string specified by user, otherwise return strong TLS 1.2-1.3 cipher suites
	# if support by local tools is detected. Detection currently supports these curl backends:
	# GnuTLS and OpenSSL (possibly also LibreSSL and BoringSSL). Return value can be empty.
	get_ciphersuites_for_curl() {
	if [ -n "${RUSTUP_TLS_CIPHERSUITES-}" ]; then
	# user specified custom cipher suites, assume they know what they're doing
	RETVAL="$RUSTUP_TLS_CIPHERSUITES"
	return
	fi

	local _openssl_syntax="no"
	local _gnutls_syntax="no"
	local _backend_supported="yes"
	if curl -V \| grep -q ' OpenSSL/'; then
	_openssl_syntax="yes"
	elif curl -V \| grep -iq ' LibreSSL/'; then
	_openssl_syntax="yes"
	elif curl -V \| grep -iq ' BoringSSL/'; then
	_openssl_syntax="yes"
	elif curl -V \| grep -iq ' GnuTLS/'; then
	_gnutls_syntax="yes"
	else
	_backend_supported="no"
	fi

	local _args_supported="no"
	if [ "$_backend_supported" = "yes" ]; then
	# "unspecified" is for arch, allows for possibility old OS using macports, homebrew, etc.
	if check_help_for "notspecified" "curl" "--tlsv1.2" "--ciphers" "--proto"; then
	_args_supported="yes"
	fi
	fi

	local _cs=""
	if [ "$_args_supported" = "yes" ]; then
	if [ "$_openssl_syntax" = "yes" ]; then
	_cs=$(get_strong_ciphersuites_for "openssl")
	elif [ "$_gnutls_syntax" = "yes" ]; then
	_cs=$(get_strong_ciphersuites_for "gnutls")
	fi
	fi

	RETVAL="$_cs"
	}

	# Return cipher suite string specified by user, otherwise return strong TLS 1.2-1.3 cipher suites
	# if support by local tools is detected. Detection currently supports these wget backends:
	# GnuTLS and OpenSSL (possibly also LibreSSL and BoringSSL). Return value can be empty.
	get_ciphersuites_for_wget() {
	if [ -n "${RUSTUP_TLS_CIPHERSUITES-}" ]; then
	# user specified custom cipher suites, assume they know what they're doing
	RETVAL="$RUSTUP_TLS_CIPHERSUITES"
	return
	fi

	local _cs=""
	if wget -V \| grep -q '\-DHAVE_LIBSSL'; then
	# "unspecified" is for arch, allows for possibility old OS using macports, homebrew, etc.
	if check_help_for "notspecified" "wget" "TLSv1_2" "--ciphers" "--https-only" "--secure-protocol"; then
	_cs=$(get_strong_ciphersuites_for "openssl")
	fi
	elif wget -V \| grep -q '\-DHAVE_LIBGNUTLS'; then
	# "unspecified" is for arch, allows for possibility old OS using macports, homebrew, etc.
	if check_help_for "notspecified" "wget" "TLSv1_2" "--ciphers" "--https-only" "--secure-protocol"; then
	_cs=$(get_strong_ciphersuites_for "gnutls")
	fi
	fi

	RETVAL="$_cs"
	}

	# Return strong TLS 1.2-1.3 cipher suites in OpenSSL or GnuTLS syntax. TLS 1.2
	# excludes non-ECDHE and non-AEAD cipher suites. DHE is excluded due to bad
	# DH params often found on servers (see RFC 7919). Sequence matches or is
	# similar to Firefox 68 ESR with weak cipher suites disabled via about:config.
	# $1 must be openssl or gnutls.
	get_strong_ciphersuites_for() {
	if [ "$1" = "openssl" ]; then
	# OpenSSL is forgiving of unknown values, no problems with TLS 1.3 values on versions that don't support it yet.
	echo "TLS_AES_128_GCM_SHA256:TLS_CHACHA20_POLY1305_SHA256:TLS_AES_256_GCM_SHA384:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384"
	elif [ "$1" = "gnutls" ]; then
	# GnuTLS isn't forgiving of unknown values, so this may require a GnuTLS version that supports TLS 1.3 even if wget doesn't.
	# Begin with SECURE128 (and higher) then remove/add to build cipher suites. Produces same 9 cipher suites as OpenSSL but in slightly different order.
	echo "SECURE128:-VERS-SSL3.0:-VERS-TLS1.0:-VERS-TLS1.1:-VERS-DTLS-ALL:-CIPHER-ALL:-MAC-ALL:-KX-ALL:+AEAD:+ECDHE-ECDSA:+ECDHE-RSA:+AES-128-GCM:+CHACHA20-POLY1305:+AES-256-GCM"
	fi
	}

	main "$@" \|\| exit 1