genfstab: deal with proper escaping/unescaping of cols

the source, target, and comments should always be mangled on writing,
and unmangled on reading.

Author: falconindy

genfstab

@@ -4,6 +4,26 @@ shopt -s extglob
 
 . ./common
 
+# we need this because %q isn't the opposite of %b
+mangle() {
+  local i= c= out=
+
+  for (( i = 0; i < ${#1}; i++ )); do
+    c=${1:i:1}
+    case $c in
+      [[:space:]])
+        printf -v c '%x' "'$c"
+        out+=\\x$c
+        ;;
+      *)
+        out+=$c
+        ;;
+    esac
+  done
+
+  printf '%s' "$out"
+}
+
 write_source() {
   local tag= spec= label= uuid= comment=()
 
@@ -31,7 +51,7 @@ write_source() {
   if [[ $spec ]]; then
     printf '%-20s' "$tag=$spec"
   else
-    printf '%-20s' "$source"
+    printf '%-20s' "$(mangle "$source")"
   fi
 }
 
@@ -84,6 +104,10 @@ findmnt -Recruno SOURCE,TARGET,FSTYPE,OPTIONS "$root" |
   # default 5th and 6th columns
   dump=0 pass=2
 
+  # unescape source and target
+  printf -v target '%b' "$target"
+  printf -v source '%b' "$source"
+
   # this is root
   target=${target#$root}
   if [[ $target = ?(/) ]]; then
@@ -98,13 +122,13 @@ findmnt -Recruno SOURCE,TARGET,FSTYPE,OPTIONS "$root" |
 
   if [[ $source =~ ^(/.+)\[(.+)\]$ ]]; then
     # it's a bind mount
-    source=$(findmnt -funcrevo TARGET "${BASH_REMATCH[1]}")${BASH_REMATCH[2]}
+    source=$(findmnt -funcevo TARGET "${BASH_REMATCH[1]}")${BASH_REMATCH[2]}
     fstype=bind
   fi
 
   # write one line
   write_source "$source"
-  printf '\t%-10s' "$target" "$fstype" "$opts"
+  printf '\t%-10s' "$(mangle "$target")" "$fstype" "$opts"
   printf '\t%s %s' "$dump" "$pass"
   printf '\n\n'
 done