[PATCH manager 0/1] ceph: tools: fix local monitor detection in purge_all_ceph_files

[PATCH manager 0/1] ceph: tools: fix local monitor detection in purge_all_ceph_files

[Kefu Chai]

While reading the code, the call 'grep($addr, @$monlist)' caught my
eye -- 'grep' made me think of grep(1), which takes a regular
expression as its first argument. But the first argument here is
clearly not a regex.

That led me to https://perldoc.perl.org/functions/grep, where I read
that grep(EXPR, LIST) evaluates EXPR for each element with $_ aliased
to the current element -- similar to a lambda that takes $_ as its
implicit parameter. The expression in our case, '$type->{$name}->{addr}',
does not reference $_ at all, making it a constant predicate. It
evaluates to the same value (the addr string) for every element in the
list, so the result is the full list length rather than a membership
test.

I then searched for a Perl operator like 'in' or 'contains' to express
membership directly, but found no such built-in. List::Util::any is the
closest equivalent -- it makes the per-element comparison explicit and
short-circuits on the first match.

Kefu Chai (1):
  ceph: tools: fix local monitor detection in purge_all_ceph_files

 PVE/Ceph/Tools.pm | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

-- 
2.47.3

[PATCH manager 1/1] ceph: tools: fix local monitor detection in purge_all_ceph_files

[Kefu Chai]

The grep call checking whether a monitor's address is in the configured
mon list did not reference $_, so it never performed a membership test:

  $is_local_mon = grep($type->{$name}->{addr}, @$monlist)

In Perl, grep(EXPR, LIST) aliases $_ to each element, but EXPR here is
'$type->{$name}->{addr}', which ignores $_. This is analogous to the
following Python, where the filter predicate is a constant:

  # wrong: sum(bool(addr) for _ in monlist) -- always len(monlist)
  # right: sum(1 for x in monlist if x == addr)

Because addr is a non-empty string (truthy), the wrong form returns the
full list length regardless of whether addr is actually in the list.
In Python terms, any(x == addr for x in monlist) would return False,
but the Perl grep returned 3 for a 3-element list.

This meant the foreign-monitor guard -- which exists to preserve config
files and keyrings when the local node is not listed as a monitor --
never triggered, and 'pveceph purge' would always delete them.

Use List::Util::any with an explicit equality check, which both expresses
the intent clearly and short-circuits on the first match.

Signed-off-by: Kefu Chai <k.chai@proxmox.com>
---
 PVE/Ceph/Tools.pm | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/PVE/Ceph/Tools.pm b/PVE/Ceph/Tools.pm
index 97ff3bd5..c731ac14 100644
--- a/PVE/Ceph/Tools.pm
+++ b/PVE/Ceph/Tools.pm
@@ -7,6 +7,7 @@ use File::Path;
 use File::Basename;
 use IO::File;
 use JSON;
+use List::Util qw(any);
 
 use PVE::Tools qw(run_command dir_glob_foreach extract_param);
 use PVE::Cluster qw(cfs_read_file);
@@ -133,7 +134,7 @@ sub purge_all_ceph_files {
         foreach my $name (keys %$type) {
             my $dir_exists = $type->{$name}->{direxists};
 
-            $is_local_mon = grep($type->{$name}->{addr}, @$monlist)
+            $is_local_mon = any { $_ eq $type->{$name}->{addr} } @$monlist
                 if $service eq 'mon';
 
             my $path = "/var/lib/ceph/$service";
-- 
2.47.3