[enh] Do not bind mounting if no backup archive is created (wip #298)

data/helpers.d/filesystem

@@ -1,4 +1,4 @@
-CAN_BIND=1
+CAN_BIND=${CAN_BIND:-1}
 
 # Bind a directory or copy it on error
 #
@@ -7,25 +7,36 @@ CAN_BIND=1
 # | arg: destdir - mountpoint or destination directory
 # | arg: as_root - 1 to execute commands as root
 ynh_bind_or_cp() {
-    SRCDIR=$1
+    local SRCDIR=$1
-    DESTDIR=$2
+    local DESTDIR=$2
-    SUDO_CMD="sudo"
+    local SUDO_CMD=
-    [[ "$3" != "1" ]] && SUDO_CMD=""
+    [[ "${3}" = "1" ]] && SUDO_CMD="sudo"
 
-    if [[ $CAN_BIND == 1 ]]; then
+    [[ ! -f "${DESTDIR}" ]] || {
-        $SUDO_CMD mkdir -p $DESTDIR
+        echo "Destination directory '${DESTDIR}' already exists" >&2
-        $SUDO_CMD mount --bind "$SRCDIR" "$DESTDIR"
+        return 1
-        if [[ $? == 0 ]]; then
+    }
-            for m in $(mount | grep " $SRCDIR" | awk '{ print $3 }'); do
+
-                $SUDO_CMD mount --bind "$m" "${DESTDIR}${m#${SRCDIR}}"
+    # attempt to bind mounting the directory
-            done
+    if [[ "${CAN_BIND}" = "1" ]]; then
-            return
+        eval $SUDO_CMD mkdir -p "${DESTDIR}"
-        fi
+
-        echo "Error: bind mounting seems to be disabled on your system."
+        if sudo mount --rbind "${SRCDIR}" "${DESTDIR}"; then
-        echo "You have maybe to check your apparmor configuration."
+            return 0
+        else
             CAN_BIND=0
+            echo "Bind mounting seems to be disabled on your system."
+            echo "You have maybe to check your apparmor configuration."
         fi
-    $SUDO_CMD cp -r "$SRCDIR" "$DESTDIR"
+
+        # delete mountpoint directory safely
+        mountpoint -q "${DESTDIR}" && sudo umount -R "${DESTDIR}"
+        eval $SUDO_CMD rm -rf "${DESTDIR}"
+    fi
+
+    # ... or just copy the directory
+    eval $SUDO_CMD mkdir -p $(dirname "${DESTDIR}")
+    eval $SUDO_CMD cp -a "${SRCDIR}" "${DESTDIR}"
 }
 
 # Create a directory under /tmp

src/yunohost/backup.py

@@ -73,6 +73,7 @@ def backup_create(name=None, description=None, output_directory=None,
     """
     # TODO: Add a 'clean' argument to clean output directory
     tmp_dir = None
+    env_var = {}
 
     # Validate what to backup
     if ignore_hooks and ignore_apps:
@@ -110,9 +111,13 @@ def backup_create(name=None, description=None, output_directory=None,
             raise MoulinetteError(errno.EIO,
                 m18n.n('backup_output_directory_not_empty'))
 
-        # Define temporary directory
+        # Do not compress, so set temporary directory to output one and
+        # disable bind mounting to prevent data loss in case of a rm
+        # See: https://dev.yunohost.org/issues/298
         if no_compress:
+            logger.debug('bind mounting will be disabled')
             tmp_dir = output_directory
+            env_var['CAN_BIND'] = 0
     else:
         output_directory = archives_path
 
@@ -159,7 +164,8 @@ def backup_create(name=None, description=None, output_directory=None,
 
         if not hooks or hooks_filtered:
             logger.info(m18n.n('backup_running_hooks'))
-            ret = hook_callback('backup', hooks_filtered, args=[tmp_dir])
+            ret = hook_callback('backup', hooks_filtered, args=[tmp_dir],
+                                env=env_var)
             if ret['succeed']:
                 info['hooks'] = ret['succeed']
 
@@ -216,8 +222,9 @@ def backup_create(name=None, description=None, output_directory=None,
                 subprocess.call(['install', '-Dm555', app_script, tmp_script])
 
                 # Prepare env. var. to pass to script
-                env_dict = {}
+                app_id, app_instance_nb = _parse_app_instance_name(
-                app_id, app_instance_nb = _parse_app_instance_name(app_instance_name)
+                    app_instance_name)
+                env_dict = env_var.copy()
                 env_dict["YNH_APP_ID"] = app_id
                 env_dict["YNH_APP_INSTANCE_NAME"] = app_instance_name
                 env_dict["YNH_APP_INSTANCE_NUMBER"] = str(app_instance_nb)