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[PULL 35/35] vl: Unlink absolute PID file path
From: |
Hanna Reitz |
Subject: |
[PULL 35/35] vl: Unlink absolute PID file path |
Date: |
Tue, 12 Jul 2022 20:08:53 +0200 |
After writing the PID file, we register an exit notifier to unlink it
when the process terminates. However, if the process has changed its
working directory in the meantime (e.g. in os_setup_post() when
daemonizing), this will not work when the PID file path was relative.
Therefore, pass the absolute path (created with realpath()) to the
unlink() call in the exit notifier.
(realpath() needs a path pointing to an existing file, so we cannot use
it before qemu_write_pidfile().)
Reproducer:
$ cd /tmp
$ qemu-system-x86_64 --daemonize --pidfile qemu.pid
$ file qemu.pid
qemu.pid: ASCII text
$ kill $(cat qemu.pid)
$ file qemu.pid
qemu.pid: ASCII text
(qemu.pid should be gone after the process has terminated.)
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220609122701.17172-4-hreitz@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
---
softmmu/vl.c | 30 ++++++++++++++++++++++++++----
1 file changed, 26 insertions(+), 4 deletions(-)
diff --git a/softmmu/vl.c b/softmmu/vl.c
index 36f46fcdad..aabd82e09a 100644
--- a/softmmu/vl.c
+++ b/softmmu/vl.c
@@ -1522,11 +1522,18 @@ machine_parse_property_opt(QemuOptsList *opts_list,
const char *propname,
}
static const char *pid_file;
-static Notifier qemu_unlink_pidfile_notifier;
+struct UnlinkPidfileNotifier {
+ Notifier notifier;
+ char *pid_file_realpath;
+};
+static struct UnlinkPidfileNotifier qemu_unlink_pidfile_notifier;
static void qemu_unlink_pidfile(Notifier *n, void *data)
{
- unlink(pid_file);
+ struct UnlinkPidfileNotifier *upn;
+
+ upn = DO_UPCAST(struct UnlinkPidfileNotifier, notifier, n);
+ unlink(upn->pid_file_realpath);
}
static const QEMUOption *lookup_opt(int argc, char **argv,
@@ -2430,13 +2437,28 @@ static void qemu_maybe_daemonize(const char *pid_file)
rcu_disable_atfork();
if (pid_file) {
+ char *pid_file_realpath = NULL;
+
if (!qemu_write_pidfile(pid_file, &err)) {
error_reportf_err(err, "cannot create PID file: ");
exit(1);
}
- qemu_unlink_pidfile_notifier.notify = qemu_unlink_pidfile;
- qemu_add_exit_notifier(&qemu_unlink_pidfile_notifier);
+ 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);
+ }
+
+ qemu_unlink_pidfile_notifier = (struct UnlinkPidfileNotifier) {
+ .notifier = {
+ .notify = qemu_unlink_pidfile,
+ },
+ .pid_file_realpath = pid_file_realpath,
+ };
+ qemu_add_exit_notifier(&qemu_unlink_pidfile_notifier.notifier);
}
}
--
2.35.3
- [PULL 21/35] block: Export blk_pwritev_part() in block-backend-io.h, (continued)
- [PULL 21/35] block: Export blk_pwritev_part() in block-backend-io.h, Hanna Reitz, 2022/07/12
- [PULL 18/35] block: Implement blk_{pread, pwrite}() using generated_co_wrapper, Hanna Reitz, 2022/07/12
- [PULL 26/35] block: Implement blk_flush() using generated_co_wrapper, Hanna Reitz, 2022/07/12
- [PULL 27/35] block: Add blk_co_ioctl(), Hanna Reitz, 2022/07/12
- [PULL 30/35] block: Remove remaining unused symbols in coroutines.h, Hanna Reitz, 2022/07/12
- [PULL 23/35] block: Add blk_co_pwrite_compressed(), Hanna Reitz, 2022/07/12
- [PULL 29/35] block: Reorganize some declarations in block-backend-io.h, Hanna Reitz, 2022/07/12
- [PULL 32/35] iotests/297: Have mypy ignore unused ignores, Hanna Reitz, 2022/07/12
- [PULL 33/35] qsd: Unlink absolute PID file path, Hanna Reitz, 2022/07/12
- [PULL 34/35] vl: Conditionally register PID file unlink notifier, Hanna Reitz, 2022/07/12
- [PULL 35/35] vl: Unlink absolute PID file path,
Hanna Reitz <=
- Re: [PULL 00/35] Block patches, Peter Maydell, 2022/07/13