[pve-devel] [PATCH http-server 3/3] anyevent: handle 'disconnected' flag in client_do_disconnect() itself

From: Fiona Ebner <f.ebner@proxmox.com>
To: pve-devel@lists.proxmox.com
Subject: [pve-devel] [PATCH http-server 3/3] anyevent: handle 'disconnected' flag in client_do_disconnect() itself
Date: Tue,  8 Apr 2025 16:20:14 +0200	[thread overview]
Message-ID: <20250408142014.86344-4-f.ebner@proxmox.com> (raw)
In-Reply-To: <20250408142014.86344-1-f.ebner@proxmox.com>

Commit f737984 ("fix #4816: do not disconnect twice if client sends no
data") introduced a 'disconnected' flag in the request state to avoid
duplicate calls to client_do_disconnect() for a given client. The flag
is only set and checked in the on_error callback of the handle
however. Do this more centrally at the beginning of the
client_do_disconnect() function itself to catch all callers and code
paths that could lead to a duplicate call. For example, while not
currently known to cause issues, the on_eof handler might re-enter the
function.

Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
---
 src/PVE/APIServer/AnyEvent.pm | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/src/PVE/APIServer/AnyEvent.pm b/src/PVE/APIServer/AnyEvent.pm
index db14a7d..b71a9a5 100644
--- a/src/PVE/APIServer/AnyEvent.pm
+++ b/src/PVE/APIServer/AnyEvent.pm
@@ -136,6 +136,13 @@ sub cleanup_reqstate {
 sub client_do_disconnect {
     my ($self, $reqstate) = @_;
 
+    # Avoid any re-entrant call. For example, the on_error callback can be called twice for the same
+    # connection/handle if the timeout is reached before any data has been received. The on_error
+    # callback might also get invoked as part of the stoptls() call during shutdown below, which is
+    # another situation where the function would be re-entered without this check.
+    return if $reqstate->{disconnected};
+    $reqstate->{disconnected} = 1;
+
     cleanup_reqstate($reqstate, 1);
 
     my $shutdown_hdl = sub {
@@ -1911,13 +1918,7 @@ sub accept_connections {
 		    my ($hdl, $fatal, $message) = @_;
 		    eval {
 			$self->log_aborted_request($reqstate, $message);
-			# this error callback can be called twice for the same
-			# connection/handle if the timeout is reached before
-			# any data has been received, avoid misleading errors
-			if (!$reqstate->{disconnected}) {
-			    $reqstate->{disconnected} = 1;
-			    $self->client_do_disconnect($reqstate);
-			}
+			$self->client_do_disconnect($reqstate);
 		    };
 		    if (my $err = $@) { syslog('err', "$err"); }
 		},
-- 
2.39.5



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