Merge pull request #2622 from nabijaczleweli/master

Detect and warn about x32

Author: kinnison

rustup-init.sh

@@ -159,6 +159,17 @@ get_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=$2
@@ -338,7 +349,24 @@ get_architecture() {
     if [ "${_ostype}" = unknown-linux-gnu ] && [ "${_bitness}" -eq 32 ]; then
         case $_cputype in
             x86_64)
-                _cputype=i686
+                if [ -n "${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)