diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..25a5efc
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "ext/rustup"]
+	path = ext/rustup
+	url = https://salsa.debian.org/rust-team/rustup.git
diff --git a/ext/rustup b/ext/rustup
new file mode 160000
index 0000000..c31b781
--- /dev/null
+++ b/ext/rustup
@@ -0,0 +1 @@
+Subproject commit c31b781f1a50f4aa20c2d1b8f9aa661f1fcd4c40
diff --git a/src/rustup/debian/changelog b/src/rustup/debian/changelog
new file mode 100644
index 0000000..7277061
--- /dev/null
+++ b/src/rustup/debian/changelog
@@ -0,0 +1,5 @@
+rust-rustup (1.21.1-1) UNRELEASED-FIXME-AUTOGENERATED-DEBCARGO; urgency=medium
+
+  * Package rustup 1.21.1 from local source using debcargo 2.4.3
+
+ -- Ximin Luo <infinity0@debian.org>  Mon, 04 May 2020 18:00:06 +0100
diff --git a/src/rustup/debian/copyright b/src/rustup/debian/copyright
new file mode 100644
index 0000000..f69bb02
--- /dev/null
+++ b/src/rustup/debian/copyright
@@ -0,0 +1 @@
+FIXME fill me in using ./copyright.debcargo.hint as a guide
diff --git a/src/rustup/debian/copyright.debcargo.hint b/src/rustup/debian/copyright.debcargo.hint
new file mode 100644
index 0000000..1559f8a
--- /dev/null
+++ b/src/rustup/debian/copyright.debcargo.hint
@@ -0,0 +1,60 @@
+Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
+Upstream-Name: rustup
+Upstream-Contact:
+ Daniel Silverstone <dsilvers@digital-scurf.org>
+ Diggory Blake <diggsey@googlemail.com>
+Source: https://github.com/rust-lang/rustup.rs
+
+Files: *
+Copyright:
+ FIXME (overlay) UNKNOWN-YEARS Daniel Silverstone <dsilvers@digital-scurf.org>
+ FIXME (overlay) UNKNOWN-YEARS Diggory Blake <diggsey@googlemail.com>
+License: MIT or Apache-2.0
+Comment:
+ FIXME (overlay): Since upstream copyright years are not available in
+ Cargo.toml, they were extracted from the upstream Git repository. This may not
+ be correct information so you should review and fix this before uploading to
+ the archive.
+
+Files: ./LICENSE-MIT
+Copyright: 2016 The Rust Project Developers
+License: UNKNOWN-LICENSE; FIXME (overlay)
+Comment:
+ FIXME (overlay): These notices are extracted from files. Please review them
+ before uploading to the archive.
+
+Files: ./www/fonts/OFL.txt
+Copyright: 2011, Raph Levien (firstname.lastname@gmail.com), Copyright (c) 2012, Cyreal (cyreal.org)
+License: UNKNOWN-LICENSE; FIXME (overlay)
+Comment:
+ FIXME (overlay): These notices are extracted from files. Please review them
+ before uploading to the archive.
+
+Files: debian/*
+Copyright:
+ 2020 Debian Rust Maintainers <pkg-rust-maintainers@alioth-lists.debian.net>
+ 2020 Ximin Luo <infinity0@debian.org>
+License: MIT or Apache-2.0
+
+License: Apache-2.0
+ Debian systems provide the Apache 2.0 license in
+ /usr/share/common-licenses/Apache-2.0
+
+License: MIT
+ Permission is hereby granted, free of charge, to any person obtaining a copy
+ of this software and associated documentation files (the "Software"), to deal
+ in the Software without restriction, including without limitation the rights
+ to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ copies of the Software, and to permit persons to whom the Software is
+ furnished to do so, subject to the following conditions:
+ .
+ The above copyright notice and this permission notice shall be included in all
+ copies or substantial portions of the Software.
+ .
+ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+ AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ SOFTWARE.
diff --git a/src/rustup/debian/debcargo.toml b/src/rustup/debian/debcargo.toml
new file mode 100644
index 0000000..451cef3
--- /dev/null
+++ b/src/rustup/debian/debcargo.toml
@@ -0,0 +1,3 @@
+overlay = "."
+uploaders = ["Ximin Luo <infinity0@debian.org>"]
+crate_src_path = "../../../ext/rustup"
diff --git a/vars.sh.frag b/vars.sh.frag
index 6ab3ead..fae9302 100644
--- a/vars.sh.frag
+++ b/vars.sh.frag
@@ -55,8 +55,15 @@
 CRATE="$1"
 VER="$2"
 
-PKGNAME=${PKGNAME:-$($DEBCARGO deb-src-name "$CRATE" $VER || abort 1 "couldn't find crate $CRATE")}
-PKGBASE=${PKGBASE:-$($DEBCARGO deb-src-name "$CRATE" || abort 1 "couldn't find crate $CRATE")}
+if [ -n "$CRATE" -a -z "$VER" ] && grep -q crate_src_path "src/$CRATE/debian/debcargo.toml"; then
+	# special hack for crate_src_path, could be cleaner...
+	PKGNAME="$CRATE"
+	PKGBASE="$CRATE"
+else
+	PKGNAME=${PKGNAME:-$($DEBCARGO deb-src-name "$CRATE" $VER || abort 1 "couldn't find crate $CRATE")}
+	PKGBASE=${PKGBASE:-$($DEBCARGO deb-src-name "$CRATE" || abort 1 "couldn't find crate $CRATE")}
+fi
+
 PKGDIR_REL="src/$PKGNAME"
 PKGDIR="$PWD/$PKGDIR_REL"
 BUILDDIR="$PWD/build/$PKGNAME"