cgit-chroot: Rename to skein-infra

Be more clear about the purpose of this script and rename it to
"skein-infra" since users might expect a program carrying "chroot" in
its name to enter or otherwise manage a chroot.

Additionally, use a consistent format for the environment variables
controlling the locations of the cgit chroot and git repositories.

1 files changed, 77 insertions, 0 deletions

diff --git a/skein-infra b/skein-infra
new file mode 100755
index 0000000..44f55a5
--- /dev/null
+++ b/skein-infra
@@ -0,0 +1,77 @@
+#!/bin/sh
+
+set -e
+
+SKEIN_CGIT_ROOT=${SKEIN_CGIT_ROOT:-/srv/cgit}
+SKEIN_GIT_ROOT=${SKEIN_GIT_ROOT:-/srv/git}
+
+usage() {
+	printf 'usage: skein-infra setup|teardown\n' >&2
+	exit 1
+}
+
+log() {
+	printf ' %s %s\n' "$1" "$2"
+}
+
+ladd() {
+	log + "$1"
+}
+
+ldel() {
+	log - "$1"
+}
+
+remove_prefix() {
+	printf "%s" "${1#$SKEIN_CGIT_ROOT/*}"
+}
+
+bind_mount() {
+	mkdir "$2"
+	mount --rbind "$1" "$2"
+	mount --make-rslave "$2"
+	ladd "$(remove_prefix "$2")"
+}
+
+bind_umount() {
+	umount "$i"
+	rmdir "$i"
+	ldel "$(remove_prefix "$i")"
+}
+
+setup() {
+	mkdir "$SKEIN_CGIT_ROOT"/dev
+	mknod "$SKEIN_CGIT_ROOT"/dev/null c 1 3
+	chmod 666 "$SKEIN_CGIT_ROOT"/dev/null
+
+	for i in "$SKEIN_CGIT_ROOT"/instances/*; do
+		test -d "$i" || continue
+		user=$(basename "$i")
+		id -ru "$user" >/dev/null || continue
+
+		git_repo_dir="${SKEIN_GIT_ROOT}/$user"
+		test -d "$git_repo_dir" || continue
+
+		instance_repo_dir="$SKEIN_CGIT_ROOT"/instances/$user/repos
+
+		bind_mount "$git_repo_dir" "$instance_repo_dir"
+		chmod 0701 "$instance_repo_dir"
+	done
+}
+
+teardown() {
+	rm "$SKEIN_CGIT_ROOT"/dev/null
+	rmdir "$SKEIN_CGIT_ROOT"/dev
+
+	for i in "$SKEIN_CGIT_ROOT"/instances/*/repos; do
+		bind_umount "$i"
+	done
+}
+
+test $# -eq 1 || usage
+
+case $1 in
+	setup) setup;;
+	teardown) teardown;;
+	*) usage;;
+esac