Add time_elapsed() function, subsuming $local_top_time

Generalize the elapsed time tracking in local-top so that it can be used
elsewhere. This requires some additional quoting in local_device_setup()
comparisons to pass shellcheck.

Now that the reference time is recorded earlier (in init vs. local-top),
the rootdev wait time will now be reduced by however long it it takes to
process init-premount. The belief is that our wait time is sufficiently
long for that to be negligible. Also, this could potentially break any
local-top scripts that use $local_top_time directly. A survey of
the current packages in sid shows no packages that contain a file under
/usr/share/initramfs-tools/scripts/local-top/ that contain "local_top_time".

Signed-off-by: dann frazier <dannf@debian.org>

init

@@ -218,6 +218,10 @@ maybe_break modules
 load_modules
 [ "$quiet" != "y" ] && log_end_msg
 
+starttime="$(_uptime)"
+starttime=$((starttime + 1)) # round up
+export starttime
+
 if [ "$ROOTDELAY" ]; then
 	sleep "$ROOTDELAY"
 fi
@@ -310,6 +314,7 @@ unset noresume
 unset fastboot
 unset forcefsck
 unset fsckfix
+unset starttime
 
 # Move virtual filesystems over to the real filesystem
 mount -n -o move /sys ${rootmnt}/sys

scripts/functions

@@ -144,6 +144,25 @@ load_modules()
 	fi
 }
 
+_uptime() {
+    local uptime
+    uptime="$(cat /proc/uptime)"
+    uptime="${uptime%%[. ]*}"
+    echo "$uptime"
+}
+
+time_elapsed() {
+    # shellcheck disable=SC2154
+    if [ -z "$starttime" ]; then
+        log_failure_msg "time_elapsed() called before \$starttime initialized"
+        echo 0
+    fi
+    local delta
+    delta="$(_uptime)"
+    delta=$((delta - starttime))
+    echo "$delta"
+}
+
 # lilo compatibility
 parse_numeric() {
 	case $1 in

scripts/local

@@ -8,14 +8,6 @@ local_top()
 		[ "$quiet" != "y" ] && log_end_msg
 	fi
 	local_top_used=yes
-
-	# Start time for measuring elapsed time in local_device_setup
-	if [ -z "${local_top_time}" ]; then
-		local_top_time="$(cat /proc/uptime)"
-		local_top_time="${local_top_time%%[. ]*}"
-		local_top_time=$((local_top_time + 1)) # round up
-		export local_top_time
-	fi
 }
 
 local_block()
@@ -44,7 +36,6 @@ local_bottom()
 	fi
 	local_premount_used=no
 	local_top_used=no
-	unset local_top_time
 }
 
 # $1=device ID to mount
@@ -94,9 +85,7 @@ local_device_setup()
 
 		while true; do
 			sleep 1
-			time_elapsed="$(cat /proc/uptime)"
-			time_elapsed="${time_elapsed%%[. ]*}"
-			time_elapsed=$((time_elapsed - local_top_time))
+			time_elapsed="$(time_elapsed)"
 
 			local_block "${dev_id}"
 
@@ -113,7 +102,7 @@ local_device_setup()
 				else
 					break
 				fi
-				if [ ${count} -ge ${time_elapsed} ]; then
+				if [ "${count}" -ge "${time_elapsed}" ]; then
 					break;
 				fi
 				/scripts/local-block/mdadm "${dev_id}"
@@ -125,7 +114,7 @@ local_device_setup()
 				log_end_msg 0
 				break
 			fi
-			if [ ${time_elapsed} -ge "${slumber}" ]; then
+			if [ "${time_elapsed}" -ge "${slumber}" ]; then
 				log_end_msg 1 || true
 				break
 			fi