init: daemonize: defuse PID file resolve error to warning

fixes file restore, where we actively unlink the PID file of the
transient VM ourself after opening it - while we use it only for
tracking when the QEMU process itself has finished start up, it's
easier and cleaner to fix this regression now, than to rework that to
something that doesn't depends on the PID file at all.

Applying Fiona's patch as patch-patch tracked under extra, as I
expect that something similar to this gets accepted upstreamed.

Link: https://lists.proxmox.com/pipermail/pve-devel/2022-October/054448.html
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
master
Thomas Lamprecht 2022-10-28 10:22:21 +02:00
parent bf03cd367f
commit 509409fb64
2 changed files with 43 additions and 0 deletions

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@ -0,0 +1,42 @@
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 706bd7cff7..3381c56af7 100644
--- a/softmmu/vl.c
+++ b/softmmu/vl.c
@@ -2438,10 +2438,11 @@ 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) {

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@ -2,6 +2,7 @@ extra/0001-monitor-qmp-fix-race-with-clients-disconnecting-earl.patch
extra/0002-block-io_uring-revert-Use-io_uring_register_ring_fd-.patch
extra/0003-virtiofsd-use-g_date_time_get_microsecond-to-get-sub.patch
extra/0004-chardev-fix-segfault-in-finalize.patch
extra/0005-init-daemonize-defuse-PID-file-resolve-error.patch
bitmap-mirror/0001-drive-mirror-add-support-for-sync-bitmap-mode-never.patch
bitmap-mirror/0002-drive-mirror-add-support-for-conditional-and-always-.patch
bitmap-mirror/0003-mirror-add-check-for-bitmap-mode-without-bitmap.patch