From 065455440d6115558ce571df07fda5219ea3f05b Mon Sep 17 00:00:00 2001
From: Alice Gaudon <alice@gaudon.pro>
Date: Sat, 24 Apr 2021 11:29:51 +0200
Subject: [PATCH] zsc-sync.sh: diversify error codes, fix error detection

---
 zsc-sync.sh | 41 +++++++++++++++++++++++++++++------------
 1 file changed, 29 insertions(+), 12 deletions(-)

diff --git a/zsc-sync.sh b/zsc-sync.sh
index 7114544..1304bf5 100755
--- a/zsc-sync.sh
+++ b/zsc-sync.sh
@@ -30,11 +30,28 @@ update_remote_state() {
 	echo "Fetching remote snapshots..."
 	remote_snapshots=$(ssh $REMOTE zfs list -H -t snapshot -o name -s creation)
 
+	r=$?
+	if [ $r -ne 0 ]; then
+		return $r
+	fi
+
 	echo "Fetching subdatasets..."
 	remote_subdatasets=$(ssh $REMOTE zfs list -H -o name -s creation -r "$REMOTE_ROOT_DATASET")
 
+	r=$?
+	if [ $r -ne 0 ]; then
+		return $r
+	fi
+
 	echo "Fetching resume tokens..."
 	resume_tokens=$(ssh $REMOTE zfs get -H -p receive_resume_token -o name,value -t filesystem)
+
+	r=$?
+	if [ $r -ne 0 ]; then
+		return $r
+	fi
+
+	return 0
 }
 
 
@@ -46,9 +63,9 @@ resume_transfer() {
 	RESUME_TOKEN=$(echo -e "$resume_tokens" | grep -P "^$remote_dataset\t.*\$" | cut -d$'\t' -f2)
 	if [ "$RESUME_TOKEN" != "" ] && [ "$RESUME_TOKEN" != "-" ]; then
 		echo "Resuming interrupted transfer..."
-		zfs send -v -t "$RESUME_TOKEN" | ssh $REMOTE zfs receive -Fu -s "$remote_dataset" || return 1
+		zfs send -v -t "$RESUME_TOKEN" | ssh $REMOTE zfs receive -Fu -s "$remote_dataset" || return 10
 		echo "Resumed transfer finished."
-		update_remote_state
+		update_remote_state || return 20
 		return 0
 	fi
 
@@ -78,7 +95,7 @@ handle_dataset() {
 	echo
 
 
-	resume_transfer "$TARGET_REMOTE_DATASET" || return 1
+	resume_transfer "$TARGET_REMOTE_DATASET" || return 11
 
 
 	### Sync existing snapshots ###
@@ -120,7 +137,7 @@ handle_dataset() {
 		if [ $RECURSIVE = true ] ; then
 			recu="-R"
 		fi
-		zfs send -v -p $recu $incr "$DATASET@$TO_SNAPSHOT" | ssh $REMOTE zfs receive -Fu -s "$TARGET_REMOTE_DATASET" || return 1
+		zfs send -v -p $recu $incr "$DATASET@$TO_SNAPSHOT" | ssh $REMOTE zfs receive -Fu -s "$TARGET_REMOTE_DATASET" || return 12
 
 		echo
 		echo "Done"
@@ -140,7 +157,7 @@ init_subdataset() {
 	TARGET_REMOTE_DATASET="$REMOTE_ROOT_DATASET/"$(echo -e $PARENT_DATASET | sed -r "s/\//_/g")"/"${DATASET:$(echo -e "$PARENT_DATASET" | wc -c)}
 
 
-	resume_transfer "$TARGET_REMOTE_DATASET" || return 1
+	resume_transfer "$TARGET_REMOTE_DATASET" || return 13
 
 	if [ $(echo -e "$remote_subdatasets" | grep -e "^$TARGET_REMOTE_DATASET\$" | wc -l) -eq 0 ]; then
 		echo "Subdataset not found on $TARGET_REMOTE_DATASET, initializing..."
@@ -149,11 +166,11 @@ init_subdataset() {
 
 		if test -z "$LOCAL_SNAPSHOT"; then
 			echo "No local snapshot"
-			return 1
+			return 14
 		fi
 
 		echo "[$DATASET@$LOCAL_SNAPSHOT -> $TARGET_REMOTE_DATASET]"
-		zfs send -v -p "$DATASET@$LOCAL_SNAPSHOT" | ssh $REMOTE zfs receive -Fu -s "$TARGET_REMOTE_DATASET" || return 1
+		zfs send -v -p "$DATASET@$LOCAL_SNAPSHOT" | ssh $REMOTE zfs receive -Fu -s "$TARGET_REMOTE_DATASET" || return 15
 
 		echo
 		echo "--- Done"
@@ -162,7 +179,7 @@ init_subdataset() {
 		echo
 		echo "--- Subdataset $TARGET_REMOTE_DATASET is out of date compared to parent dataset. Syncing first..."
 
-		handle_dataset "$DATASET" false "" "$TARGET_REMOTE_DATASET" || return 1
+		handle_dataset "$DATASET" false "" "$TARGET_REMOTE_DATASET" || return 16
 
 		echo
 		echo "--- Done"
@@ -173,7 +190,7 @@ init_subdataset() {
 }
 
 
-update_remote_state
+update_remote_state || exit 21
 
 HAD_ERROR=0
 
@@ -216,7 +233,7 @@ for line in $(cat "$ZSC_CONFIG") ; do
 		for p in "${SUBDATASETS[@]}"; do
 			init_subdataset $p $dataset "$latest_synchronized_snapshot"
 			r=$?
-			if [ ! $r ]; then
+			if [ $r -ne 0 ]; then
 				echo "Error while initing subdataset $p, continuing"
 				if [ $HAD_ERROR ]; then
 					HAD_ERROR=$r
@@ -227,12 +244,12 @@ for line in $(cat "$ZSC_CONFIG") ; do
 		echo "----------"
 		echo
 
-		update_remote_state
+		update_remote_state || exit 22
 	fi
 
 	handle_dataset $dataset $recursive $prefix
 	r=$?
-	if [ ! $r ]; then
+	if [ $r -ne 0 ]; then
 		echo "Error while initing subdataset $p, continuing"
 		if [ $HAD_ERROR ]; then
 			HAD_ERROR=$r