From: Elan Ruusamäe <glen@delfi.ee>
Date: Thu, 19 Jun 2014 19:58:35 +0000 (+0300)
Subject: add AUTOSWAP feature
X-Git-Tag: 0.4.12~1
X-Git-Url: http://git.pld-linux.org/?p=projects%2Frc-scripts.git;a=commitdiff_plain;h=03e0c0fad83a7a6fc0033ead0f1805d6bda4d855

add AUTOSWAP feature

inspired from initscripts 9.39-1
---

diff --git a/doc/sysconfig.txt b/doc/sysconfig.txt
index 063a332b..635d0545 100644
--- a/doc/sysconfig.txt
+++ b/doc/sysconfig.txt
@@ -1,6 +1,13 @@
 Files in /etc/sysconfig
 =======================
 
+/etc/sysconfig/system:
+
+  AUTOSWAP=yes|no
+     Set to 'yes' to enable automatic swapon of all partitions with
+     the proper swap magic. This allows setting up swap without editing
+     /etc/fstab.
+
 /etc/sysconfig/keyboard:
 
   KEYTABLE=<keytable file>
diff --git a/lib/functions b/lib/functions
index e32f2d08..1b1b9726 100644
--- a/lib/functions
+++ b/lib/functions
@@ -174,8 +174,7 @@ is_empty_file() {
 
 # returns OK if $1 contains $2
 strstr() {
-	local a=$2
-	[ "${1#*$a*}" = "$1" ] && return 1
+	[ "${1#*$2*}" = "$1" ] && return 1
 	return 0
 }
 
diff --git a/rc.d/rc.sysinit b/rc.d/rc.sysinit
index 0b9d5c72..e14ad740 100755
--- a/rc.d/rc.sysinit
+++ b/rc.d/rc.sysinit
@@ -102,6 +102,21 @@ parse_cmdline() {
 	done
 }
 
+# resolve a device node to its major:minor numbers in decimal or hex
+get_numeric_dev() {
+	local dev=$1 enc=${2:-hex} res
+
+	res=$(stat -Lc "%t:%T" "$dev")
+	if [ "$enc" = dec ]; then
+		local oifs=$IFS
+		IFS=":"
+		set -- $res
+		IFS=$oifs
+		res=$((0x$1)):$((0x$2))
+	fi
+	echo -n $res
+}
+
 # setup SELINUX variable
 init_selinux() {
 	# user knows!
@@ -162,6 +177,32 @@ relabel_selinux() {
 	echo $SELINUX > $selinuxfs/enforce
 }
 
+# Enable automatic swapon of all partitions with the proper swap magic.
+# This allows setting up swap without editing /etc/fstab.
+enable_autoswap() {
+	local swappartitions=$(blkid -t TYPE=swap -o device)
+	if [ -z "$swappartitions" ]; then
+		return
+	fi
+
+	local curswap=$(awk '/^\/dev/ { print $1 }' /proc/swaps | while read x; do echo -n " "; get_numeric_dev $x; echo -n " "; done)
+
+	local partition
+	for partition in $swappartitions; do
+		[ ! -e $partition ] && continue
+		majmin=$(get_numeric_dev $partition)
+		if ! strstr "$curswap" " $majmin "; then
+			run_cmd "$(nls 'Enabling local swap partitions: %s' $partition)" swapon $partition
+		fi
+	done
+}
+
+
+enable_swap() {
+	run_cmd "Activating swap" swapon -a "$@"
+	is_yes "$AUTOSWAP" && enable_autoswap
+}
+
 # Remove duplicate entries from mtab (for vserver guest use only)
 clean_vserver_mtab() {
 	> /etc/mtab.clean
@@ -494,7 +535,7 @@ if ! is_yes "$VSERVER" && [[ "$container" != lxc* ]]; then
 	fi
 
 	# Start up swapping
-	run_cmd "Activating swap partitions" swapon -a -e
+	enable_swap -e
 
 	# Initialize USB controllers
 	usb=0
@@ -1005,9 +1046,7 @@ chown root:root /tmp/.ICE-unix
 is_yes "$SELINUX" && restorecon /tmp/.ICE-unix >/dev/null 2>&1
 
 if ! is_yes "$VSERVER"; then
-	run_cmd "Enabling swap space" true
-	# Right, now turn on swap in case we swap to files
-	swapon -a >/dev/null 2>&1
+	enable_swap
 	emit --no-wait all-swaps
 
 	# If a SCSI tape has been detected, load the st module unconditionally
diff --git a/sysconfig/system b/sysconfig/system
index f86eb736..0734c41e 100644
--- a/sysconfig/system
+++ b/sysconfig/system
@@ -80,6 +80,9 @@ EVMS_AIX=no
 # EVMS OS/2 LVM volumes
 EVMS_OS2=no
 
+# Set to 'yes' to allow probing for devices with swap signatures
+AUTOSWAP=no
+
 # LVM2
 # disable if your only LVM volume is rootfs started on initrd and want faster startup
 LVM2=yes