From d6cd9b06244b71385a93859f213f0c8f3791fe6b Mon Sep 17 00:00:00 2001
From: "Richard W.M. Jones" <rjones@redhat.com>
Date: Tue, 4 Feb 2025 10:33:31 +0000
Subject: [PATCH] lenses/fstab.aug: Allow individual mount options to be empty

Mount allows mount-option fields to be empty (I think it ignores
them), but augeas gave an error.  Allow this to be parsed, preserving
the empty option on write.

Example:
  /dev/mapper/vg00-vartmp /var/tmp xfs rw,,nodev,nosuid,noexec,relatime 0 0

Note this generalises earlier commit 5246ef0738 ("lenses/fstab.aug:
Allow comma after the last option (#838)") since "," appearing at the
end of the option list is a special case of this.

Fixes: https://issues.redhat.com/browse/RHEL-77279
Fixes: https://github.com/hercules-team/augeas/issues/832
Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
---
 lenses/fstab.aug            |  9 +++++----
 lenses/tests/test_fstab.aug | 24 ++++++++++++++++++++++++
 2 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/lenses/fstab.aug b/lenses/fstab.aug
index 8784961da..92a97a230 100644
--- a/lenses/fstab.aug
+++ b/lenses/fstab.aug
@@ -24,11 +24,12 @@ module Fstab =
          Build.opt_list lns comma
 
   (* A mount option label can't contain comma, comment, equals, or space *)
-  let optlabel = /[^,#= \n\t]+/
+  let mntoptlabel = /[^,#= \n\t]+/
 
-  let comma_sep_list (l:string) =
+  let mntopt_list (l:string) =
     let value = [ label "value" . Util.del_str "=" . ( store Rx.neg1 )? ] in
-      let lns = [ label l . store optlabel . value? ] in
+   let mntopt = [ label l . store mntoptlabel . value? ] in
+      let lns = mntopt? in
          Build.opt_list lns comma
 
   let record = [ seq "mntent" .
@@ -36,7 +37,7 @@ module Fstab =
                    [ label "spec" . store spec ] . sep_tab .
                    [ label "file" . store file ] . sep_tab .
                    vfstype_list "vfstype" .
-                   (sep_tab . comma_sep_list "opt" .
+                   (sep_tab . mntopt_list "opt" .
                     (sep_tab . [ label "dump" . store /[0-9]+/ ] .
                      ( sep_spc . [ label "passno" . store /[0-9]+/ ])? )? )?
                  . Util.comment_or_eol ]
diff --git a/lenses/tests/test_fstab.aug b/lenses/tests/test_fstab.aug
index 438f619a9..cc2398486 100644
--- a/lenses/tests/test_fstab.aug
+++ b/lenses/tests/test_fstab.aug
@@ -156,6 +156,30 @@ module Test_fstab =
     { "#comment" = "device at install: /dev/sda3" }
   }
 
+  (* Bug #832 - Allow comma after the last option *)
+  test Fstab.lns get "/dev/mapper/foo-bar / xfs defaults, 0 0\n" =
+  { "1"
+    { "spec" = "/dev/mapper/foo-bar" }
+    { "file" = "/" }
+    { "vfstype" = "xfs" }
+    { "opt" = "defaults" }
+    { "dump" = "0" }
+    { "passno" = "0" }
+  }
+
+  (* RHEL-77279 - Allow empty option *)
+  test Fstab.lns get "/dev/mapper/foo-bar / xfs rw,,nodev 0 0\n" =
+  { "1"
+    { "spec" = "/dev/mapper/foo-bar" }
+    { "file" = "/" }
+    { "vfstype" = "xfs" }
+    { "opt" = "rw" }
+    { "opt" = "" }
+    { "opt" = "nodev" }
+    { "dump" = "0" }
+    { "passno" = "0" }
+  }
+
 (* Local Variables: *)
 (* mode: caml       *)
 (* End:             *)