From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Fiona Ebner <f.ebner@proxmox.com>
Date: Fri, 28 Oct 2022 10:09:46 +0200
Subject: [PATCH] init: daemonize: defuse PID file resolve error

When proxmox-file-restore invokes QEMU, the PID file is a (temporary)
file that's already unlinked, so resolving the absolute path here
failed.

It should not be a critical error when the PID file unlink handler
can't be registered, because the path can't be resolved for whatever
reason. If the file is already gone from QEMU's perspective (i.e.
errno is ENOENT), silently ignore the error. Otherwise, print a
warning.

Reported-by: Dominik Csapak <d.csapak@proxmox.com>
Suggested-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
---
 softmmu/vl.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/softmmu/vl.c b/softmmu/vl.c
index 5115221efe..5f7f6ca981 100644
--- a/softmmu/vl.c
+++ b/softmmu/vl.c
@@ -2460,10 +2460,11 @@ static void qemu_maybe_daemonize(const char *pid_file)
 
         pid_file_realpath = g_malloc0(PATH_MAX);
         if (!realpath(pid_file, pid_file_realpath)) {
-            error_report("cannot resolve PID file path: %s: %s",
-                         pid_file, strerror(errno));
-            unlink(pid_file);
-            exit(1);
+            if (errno != ENOENT) {
+                warn_report("not removing PID file on exit: cannot resolve PID "
+                            "file path: %s: %s", pid_file, strerror(errno));
+            }
+            return;
         }
 
         qemu_unlink_pidfile_notifier = (struct UnlinkPidfileNotifier) {
