diff --git a/sync-upstream.sh b/sync-upstream.sh
new file mode 100755
index 0000000..16f0a0d
--- /dev/null
+++ b/sync-upstream.sh
@@ -0,0 +1,82 @@
+#!/bin/sh
+# Given a git source repo, generate a tarball from the desired branch, modify
+# the spec file and upload it to lookaside cache if the tarball unpacks and
+# gets patched cleanly.
+
+set -e
+
+# We want to sync from master by default.  Change this if you want to sync from
+# another branch.
+branch=master
+
+# We can't do anything without an upstream repo
+if [ $# -ne 1 ]; then
+	echo "Usage: $0 <path-to-upstream-repo>" 1>&2
+	exit 1
+fi
+
+upstream=$1
+
+srcdir=$(git --git-dir=$upstream/.git describe $branch)
+cursrc=$(sed -ne 's/^%define glibcsrcdir  \(.*\)/\1/p' glibc.spec)
+
+# Upstream has not moved forward since the last sync.
+# TODO: Some time in the future, we might want to only sync when upstream has
+# advanced more than a certain number of commits, say, 42.
+if [ "$cursrc" = "$srcdir" ]; then
+	echo "+ Already in sync with upstream."
+	exit 0
+fi
+
+# Generate and gzip the tarball from the desired branch of the repository.
+echo "+ Generating tarball."
+git --git-dir="$upstream/.git" archive --prefix="$srcdir/" "$branch" \
+	> "$srcdir.tar"
+gzip -9 "$srcdir.tar"
+echo "+ Created $srcdir.tar.gz"
+
+# Our changelog header
+cldate=$(date +'%a %b %d %Y')
+clname=$(git config --get user.name)
+clemail=$(git config --get user.email | sed 's/@/\\@/')
+
+# Getting our version and release number from the spec file.
+nv=$(perl -ne 's/^%define glibcversion (.+)/printf("%s-", $1)/e;' \
+	  -e 's/^%define glibcrelease ([0-9]+).*/printf("%d\n", $1 + 1)/e;' \
+	  glibc.spec)
+
+# Our changelog entry.
+changelog="* $cldate $clname <$clemail> - $nv\n- Sync with upstream $branch\n"
+
+# Change the glibcsrcdir variable, bump up the release number and add an extra
+# entry to the changelog.
+echo "+ Updating spec file."
+perl -pi \
+	-e "s/^(%define glibcsrcdir  ).+/\$1$srcdir/;
+	    s/^(%define glibcrelease )(\d+)/print(\$1); print(\$2 + 1);'';/e;
+	    s/^(%changelog)$/\$1\n$changelog/" \
+	glibc.spec
+
+function prep_failed {
+	# fedpkg prep failed.
+	if [ $? -ne 0 ]; then
+		echo "+ Source prep failed."
+		echo "+ Check the output in $tmpfile and fix things before committing."
+		false
+	fi
+}
+
+echo "+ Testing if fedpkg prep works."
+tmpfile=$(mktemp fedpkg-prep.out-XXXX)
+
+trap prep_failed EXIT
+fedpkg prep > "$tmpfile" 2>&1
+# Remove mess created by fedpkg prep
+rm -f "$tmpfile"
+rm -rf "$srcdir"
+echo "+ Source prep is clean, so we're good to go."
+fedpkg new-sources "$srcdir.tar.gz"
+git commit -a -m \"Sync with upstream $branch\"
+fedpkg push
+fedpkg build
+echo "+ Done!"