Merge branch 'feature/use-shld'

1 files changed, 210 insertions, 0 deletions

diff --git a/src/session.sh b/src/session.sh
new file mode 100644
index 0000000..6453fae
--- /dev/null
+++ b/src/session.sh
@@ -0,0 +1,210 @@
+# Functions for managing prokit sessions
+#
+# Copyright (C) 2014  Patrick "P. J." McDermott
+#
+# This file is part of the ProteanOS Development Kit.
+#
+# The ProteanOS Development Kit is free software: you can redistribute
+# it and/or modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# The ProteanOS Development Kit is distributed in the hope that it
+# will be useful, but WITHOUT ANY WARRANTY; without even the implied
+# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+# See the GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with the ProteanOS Development Kit.  If not, see
+# <http://www.gnu.org/licenses/>.
+
+session_id=
+session_root=
+session_arch=
+session_plat=
+session_mountdir=
+session_atexit=
+session_sigs=
+
+session_begin()
+{
+	local root="${1}"
+	local mountdir="${2}"
+	local atexit="${3}"
+	local installing="${4}"
+
+	rand
+	session_id=${rand_x}
+	session_root="${root}"
+	session_arch="$(cat "${root}/etc/proteanos_arch")"
+	session_plat="$(cat "${root}/etc/proteanos_plat")"
+	session_mountdir="${mountdir}"
+	session_atexit="${atexit}"
+
+	[ -d "${session_root}/prokit" ] || mkdir "${session_root}/prokit"
+	if [ -f "${session_root}/prokit/installing" ] && ! ${installing}; then
+		error 2 "$(get_msg 'install_running')"
+	fi
+
+	session_set_sigs
+
+	if ! mutex_timedlock "${session_root}/prokit/sessions.lock" 5; then
+		error 2 "$(get_msg 'cant_lock_sessions')"
+	fi
+
+	# Check for a sessions pool.
+	if [ -d "${session_root}/prokit/sessions" ]; then
+		if ! profile_file_systems_mounted "${session_root}" \
+				"${session_arch}" "${session_plat}"; then
+			# If a sessions pool exists but the file systems aren't
+			# mounted, clean up the old sessions and mount the file
+			# systems.
+			rmdir "${session_root}/prokit/sessions/"*
+			session_mount
+		fi
+	else
+		# If the sessions pool doesn't exist, create it and mount the
+		# file systems.
+		mkdir "${session_root}/prokit/sessions"
+		session_mount
+	fi
+
+	# Register the session.
+	mkdir "${session_root}/prokit/sessions/${session_id}"
+	mkdir "${session_root}/prokit/sessions/${session_id}/wd"
+	profile_bind_mount "${session_arch}" "${session_plat}" \
+		"${session_mountdir}" \
+		"${session_root}/prokit/sessions/${session_id}/wd"
+
+	mutex_unlock "${session_root}/prokit/sessions.lock"
+}
+
+session_end()
+{
+	trap : ${session_sigs}
+
+	${session_atexit}
+
+	# Unregister the session.
+	profile_bind_umount "${session_arch}" "${session_plat}" \
+		"${session_mountdir}" \
+		"${session_root}/prokit/sessions/${session_id}/wd"
+	rmdir "${session_root}/prokit/sessions/${session_id}/wd"
+	rmdir "${session_root}/prokit/sessions/${session_id}"
+
+	if ! mutex_is_unlockable "${session_root}/prokit/sessions.lock"; then
+		if ! mutex_timedlock "${session_root}/prokit/sessions.lock" 5
+		then
+			error 2 "$(get_msg 'cant_lock_sessions')"
+		fi
+	fi
+
+	# Clear the sessions pool.  If there are no more sessions, unmount the
+	# file systems.
+	if rmdir "${session_root}/prokit/sessions" 2>/dev/null; then
+		session_umount
+	fi
+
+	mutex_unlock "${session_root}/prokit/sessions.lock"
+	
+	trap - ${session_sigs}
+}
+
+session_id()
+{
+	printf '%d\n' ${session_id}
+	return 0
+}
+
+session_dir()
+{
+	printf '/prokit/sessions/%d\n' ${session_id}
+	return 0
+}
+
+session_exec()
+{
+	local args=
+	local session_dir=
+
+	args=''
+	for arg in "${@}"; do
+		arg="'$(printf '%s\n' "${arg}" | sed "s/'/'\\\\''/g")'"
+		args="${args} ${arg}"
+	done
+	session_dir="/prokit/sessions/${session_id}/wd"
+	chroot "${session_root}" /bin/sh -c "cd ${session_dir}; ${args}"
+}
+
+session_mount()
+{
+	local fs=
+	local dir=
+	local fstype=
+	local options=
+
+	while read fs dir fstype options; do
+		[ "x${dir}" = 'x' ] && continue
+		mount -t "${fstype}" -o "${options}" "${fs}" \
+			"${session_root}/${dir}"
+	done <<-EOF
+		$(profile_get_fstab "${session_arch}" "${session_plat}")
+		EOF
+}
+
+session_umount()
+{
+	local fs=
+	local dir=
+	local fstype=
+	local options=
+
+	while read fs dir fstype options; do
+		[ "x${dir}" = 'x' ] && continue
+		# umount sometimes complains that the /dev file system is busy.
+		# Here's a kludge to try to handle that.  We better make sure
+		# bind mounts get unmounted; otherwise, `rm -Rf ${root}` can be
+		# painful.
+		while ! umount "${session_root}/${dir}"; do
+			sleep 1
+		done
+	done <<-EOF
+		$(profile_get_fstab "${session_arch}" "${session_plat}" | \
+			sed -n '1!G;h;$p')
+		EOF
+}
+
+session_set_sigs()
+{
+	local i=
+	local sig=
+
+	# We need the signal *number* in the signal handler.  The only portable
+	# and easy way to get the number of a named signal is to search for it
+	# as in the following loop hack.
+	i=0
+	session_sigs=''
+	while [ ${i} -lt 127 ]; do
+		i=$(($i + 1))
+		sig="$(kill -l ${i} 2>/dev/null)" || continue
+		case "${sig}" in
+			'HUP' | 'INT' | 'QUIT' | 'ABRT' | 'ALRM' | 'TERM')
+				session_sigs="${session_sigs} ${i}"
+				trap "session_handle_sig ${i}" ${i}
+				;;
+		esac
+	done
+}
+
+session_handle_sig()
+{
+	local sig="${1}"
+
+	session_end
+
+	if [ "x${exit_status:+set}" = 'xset' ]; then
+		exit ${exit_status}
+	else
+		exit $((128 + $sig))
+	fi
+}