[fstab] Configure tmp on tmpfs

Adds a new option / configuration keys to `fstab.conf` to
configure how /tmp is created. The example shows how /tmp
is made *tmpfs* on an SSD, or on not-SSD, is just-a-directory.

FIXES #1818

src/modules/fstab/fstab.conf

@@ -61,3 +61,26 @@ ssdExtraMountOptions:
 crypttabOptions: luks
 # For Debian and Debian-based distributions, change the above line to:
 # crypttabOptions: luks,keyscript=/bin/cat
+
+# Options for handling /tmp in /etc/fstab
+# Currently default (required) and ssd are supported
+# The corresponding string can contain the following variables:
+# tmpfs: true or tmpfs: false to either mount /tmp as tmpfs or not
+# options: "<mount options>"
+#
+# Example:
+#tmpOptions:
+#    default:
+#        tmpfs: false
+#        options: ""
+#    ssd:
+#        tmpfs: true
+#        options: "defaults,noatime,mode=1777"
+#
+tmpOptions:
+    default:
+        tmpfs: false
+        options: ""
+    ssd:
+        tmpfs: true
+        options: "defaults,noatime,mode=1777"

src/modules/fstab/fstab.schema.yaml

@@ -25,4 +25,22 @@ properties:
             btrfs_swap: { type: string }
     efiMountOptions: { type: string }
     crypttabOptions: { type: string }
-required: [ mountOptions ]
+    tmpOptions:
+        type: object
+        additionalProperties: false
+        properties:
+            default:
+                type: object
+                additionalProperties: false
+                properties:
+                    tmpfs: { type: bool }
+                    options: { type: string }
+            ssd:
+                type: object
+                additionalProperties: false
+                properties:
+                    tmpfs: { type: bool }
+                    options: { type: string }
+required:
+    - mountOptions
+    - tmpOptions: default

src/modules/fstab/main.py

@@ -106,14 +106,17 @@ class FstabGenerator(object):
     :param root_mount_point:
     :param mount_options:
     :param ssd_extra_mount_options:
+    :param crypttab_options:
+    :param tmp_options:
     """
     def __init__(self, partitions, root_mount_point, mount_options,
-                 ssd_extra_mount_options, crypttab_options):
+                 ssd_extra_mount_options, crypttab_options, tmp_options):
         self.partitions = partitions
         self.root_mount_point = root_mount_point
         self.mount_options = mount_options
         self.ssd_extra_mount_options = ssd_extra_mount_options
         self.crypttab_options = crypttab_options
+        self.tmp_options = tmp_options
         self.ssd_disks = set()
         self.root_is_ssd = False
 
@@ -221,11 +224,22 @@ class FstabGenerator(object):
                         self.print_fstab_line(dct, file=fstab_file)
 
             if self.root_is_ssd:
+                # Old behavior was to mount /tmp as tmpfs
+                # New behavior is to use tmpOptions to decide
+                # if mounting /tmp as tmpfs and which options to use
+                ssd = self.tmp_options.get("ssd", {})
+                if not ssd:
+                    ssd = self.tmp_options.get("default", {})
+                # Default to True to mimic old behavior
+                tmpfs = ssd.get("tmpfs", True)
+
+                if tmpfs:
+                    options = ssd.get("options", "defaults,noatime,mode=1777")
                     # Mount /tmp on a tmpfs
                     dct = dict(device="tmpfs",
                                mount_point="/tmp",
                                fs="tmpfs",
-                           options="defaults,noatime,mode=1777",
+                               options=options,
                                check=0,
                                )
                     self.print_fstab_line(dct, file=fstab_file)
@@ -411,6 +425,7 @@ def run():
     mount_options = conf.get("mountOptions", {})
     ssd_extra_mount_options = conf.get("ssdExtraMountOptions", {})
     crypttab_options = conf.get("crypttabOptions", "luks")
+    tmp_options = conf.get("tmpOptions", {})
 
     # We rely on mount_options having a default; if there wasn't one,
     # bail out with a meaningful error.
@@ -423,7 +438,8 @@ def run():
                                root_mount_point,
                                mount_options,
                                ssd_extra_mount_options,
-                               crypttab_options)
+                               crypttab_options,
+                               tmp_options)
 
     if swap_choice is not None:
         libcalamares.job.setprogress(0.2)