[PATCH] VOLATILE_TMP_DIR: add

[Trevor Woerner <twoerner@gmail.com>]

Provide a mechanism to allow users to choose whether the /tmp directory
is on persistent storage (non-volatile) or a RAM-based tmpfs (volatile).
The default is volatile.

Works for both sysvinit-based and systemd-based systems.

Signed-off-by: Trevor Woerner <twoerner@gmail.com>
---
 meta/conf/bitbake.conf                           | 4 ++++
 meta/recipes-core/initscripts/initscripts_1.0.bb | 3 +++
 meta/recipes-core/systemd/systemd_252.5.bb       | 7 +++++++
 3 files changed, 14 insertions(+)

diff --git a/meta/conf/bitbake.conf b/meta/conf/bitbake.conf
index dcf6ce99d138..afd9e2f5527f 100644
--- a/meta/conf/bitbake.conf
+++ b/meta/conf/bitbake.conf
@@ -90,6 +90,10 @@ ROOT_HOME ??= "/home/root"
 # If set to boolean false ('no', 'n', 'false', 'f', '0'), /var/log is on persistent storage.
 VOLATILE_LOG_DIR ?= "yes"
 
+# if set to 'yes': /tmp links to /var/tmp which links to /var/volatile/tmp
+# otherwise:       /tmp is on persistent storage
+VOLATILE_TMP_DIR ?= "yes"
+
 BB_RENAMED_VARIABLES[PNBLACKLIST] = "SKIP_RECIPE"
 BB_RENAMED_VARIABLES[CVE_CHECK_PN_WHITELIST] = "CVE_CHECK_SKIP_RECIPE"
 BB_RENAMED_VARIABLES[CVE_CHECK_WHITELIST] = "CVE_CHECK_IGNORE"
diff --git a/meta/recipes-core/initscripts/initscripts_1.0.bb b/meta/recipes-core/initscripts/initscripts_1.0.bb
index 7c9d9ca4f107..4dc477bb8d69 100644
--- a/meta/recipes-core/initscripts/initscripts_1.0.bb
+++ b/meta/recipes-core/initscripts/initscripts_1.0.bb
@@ -108,6 +108,9 @@ do_install () {
 		sed -i -e '\@^d root root 0755 /var/volatile/log none$@ a\l root root 0755 /var/log /var/volatile/log' \
 			${D}${sysconfdir}/default/volatiles/00_core
 	fi
+	if [ "${VOLATILE_TMP_DIR}" != "yes" ]; then
+		sed -i -e "/\<tmp\>/d" ${D}${sysconfdir}/default/volatiles/00_core
+	fi
 	install -m 0755    ${WORKDIR}/dmesg.sh		${D}${sysconfdir}/init.d
 	install -m 0644    ${WORKDIR}/logrotate-dmesg.conf ${D}${sysconfdir}/
 
diff --git a/meta/recipes-core/systemd/systemd_252.5.bb b/meta/recipes-core/systemd/systemd_252.5.bb
index ea468da150ce..8b92b2cf425c 100644
--- a/meta/recipes-core/systemd/systemd_252.5.bb
+++ b/meta/recipes-core/systemd/systemd_252.5.bb
@@ -288,6 +288,13 @@ do_install() {
 		rm -rf ${D}${localstatedir}/log/journal/remote
 	fi
 
+	# if the user requests /tmp be on persistent storage (i.e. not volatile)
+	# then don't use a tmpfs for /tmp
+	if [ "${VOLATILE_TMP_DIR}" != "yes" ]; then
+		rm -f ${D}${rootlibdir}/systemd/system/tmp.mount
+		rm -f ${D}${rootlibdir}/systemd/system/local-fs.target.wants/tmp.mount
+	fi
+
 	install -d ${D}${systemd_system_unitdir}/graphical.target.wants
 	install -d ${D}${systemd_system_unitdir}/multi-user.target.wants
 	install -d ${D}${systemd_system_unitdir}/poweroff.target.wants
-- 
2.36.0.rc2.17.g4027e30c53