session_*(): New functions

2 files changed, 135 insertions, 0 deletions

diff --git a/lib/local.mk b/lib/local.mk
index 3de79f7..66d203f 100644
--- a/lib/local.mk
+++ b/lib/local.mk
@@ -10,6 +10,7 @@ pkgdata_sources = \
 	lib/feed.sh \
 	lib/pkg.sh \
 	lib/mutex.sh \
+	lib/session.sh \
 	lib/chroot.sh \
 	lib/opkg.sh \
 	lib/rand.sh \
diff --git a/lib/session.sh b/lib/session.sh
new file mode 100644
index 0000000..1430493
--- /dev/null
+++ b/lib/session.sh
@@ -0,0 +1,134 @@
+# 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/>.
+
+[ "x${_SESSION_SM+set}" = 'xset' ] && return 0
+_SESSION_SM=1
+
+use rand
+use mutex
+use output
+use locale
+use profile
+
+session_id=
+session_root=
+session_arch=
+session_plat=
+session_atexit=
+
+session_begin()
+{
+	local root="${1}"
+	local atexit="${2}"
+
+	rand
+	session_id=${rand_x}
+	session_root="${root}"
+	session_arch="$(cat "${root}/etc/proteanos_arch")"
+	session_plat="$(cat "${root}/etc/proteanos_plat")"
+	session_atexit="${atexit}"
+
+	if ! mutex_lock_timeout "${session_root}/prokit/sessions.lock" 5; then
+		error 2 "$(get_msg 'cant_lock_sessions')"
+	fi
+
+	# Check for a sessions pool.
+	if [ -d "${session_root}/prokit/sessions" ]; then
+		if ! profile_file_systems_mounted; then
+			# If a sessions pool exists but the file systems aren't
+			# mounted, clean up the old sessions and mount the file
+			# systems.
+			rmdir "${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/${session_id}"
+
+	mutex_unlock "${session_root}/prokit/sessions.lock"
+}
+
+session_end()
+{
+	# Unregister the session.
+	rmdir "${session_root}/prokit/sessions/${session_id}"
+
+	if ! mutex_lock_timeout "${session_root}/prokit/sessions.lock" 5; then
+		error 2 "$(get_msg 'cant_lock_sessions')"
+	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"
+}
+
+session_id()
+{
+	printf '%d\n' ${session_id}
+	return 0
+}
+
+session_mount()
+{
+	local fs=
+	local dir=
+	local fstype=
+	local options=
+
+	while read fs dir fstype options; do
+		[ "x${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
+}