From 03d2b412aaf2078425f8472f31c8a9c2340969eb Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Tue, 2 Mar 2021 14:27:46 +0000 Subject: qemu-storage-daemon: add --pidfile option Daemons often have a --pidfile option where the pid is written to a file so that scripts can stop the daemon by sending a signal. The pid file also acts as a lock to prevent multiple instances of the daemon from launching for a given pid file. QEMU, qemu-nbd, qemu-ga, virtiofsd, and qemu-pr-helper all support the --pidfile option. Add it to qemu-storage-daemon too. Reported-by: Richard W.M. Jones Signed-off-by: Stefan Hajnoczi Message-Id: <20210302142746.170535-1-stefanha@redhat.com> Reviewed-by: Richard W.M. Jones Signed-off-by: Kevin Wolf --- storage-daemon/qemu-storage-daemon.c | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) (limited to 'storage-daemon') diff --git a/storage-daemon/qemu-storage-daemon.c b/storage-daemon/qemu-storage-daemon.c index 78ddf619d4..23756fc8e5 100644 --- a/storage-daemon/qemu-storage-daemon.c +++ b/storage-daemon/qemu-storage-daemon.c @@ -59,6 +59,7 @@ #include "sysemu/runstate.h" #include "trace/control.h" +static const char *pid_file; static volatile bool exit_requested = false; void qemu_system_killed(int signal, pid_t pid) @@ -115,6 +116,8 @@ static void help(void) " See the qemu(1) man page for documentation of the\n" " objects that can be added.\n" "\n" +" --pidfile write process ID to a file after startup\n" +"\n" QEMU_HELP_BOTTOM "\n", error_get_progname()); } @@ -126,6 +129,7 @@ enum { OPTION_MONITOR, OPTION_NBD_SERVER, OPTION_OBJECT, + OPTION_PIDFILE, }; extern QemuOptsList qemu_chardev_opts; @@ -178,6 +182,7 @@ static void process_options(int argc, char *argv[]) {"monitor", required_argument, NULL, OPTION_MONITOR}, {"nbd-server", required_argument, NULL, OPTION_NBD_SERVER}, {"object", required_argument, NULL, OPTION_OBJECT}, + {"pidfile", required_argument, NULL, OPTION_PIDFILE}, {"trace", required_argument, NULL, 'T'}, {"version", no_argument, NULL, 'V'}, {0, 0, 0, 0} @@ -289,6 +294,9 @@ static void process_options(int argc, char *argv[]) qobject_unref(args); break; } + case OPTION_PIDFILE: + pid_file = optarg; + break; case 1: error_report("Unexpected argument"); exit(EXIT_FAILURE); @@ -299,6 +307,27 @@ static void process_options(int argc, char *argv[]) loc_set_none(); } +static void pid_file_cleanup(void) +{ + unlink(pid_file); +} + +static void pid_file_init(void) +{ + Error *err = NULL; + + if (!pid_file) { + return; + } + + if (!qemu_write_pidfile(pid_file, &err)) { + error_reportf_err(err, "cannot create PID file: "); + exit(EXIT_FAILURE); + } + + atexit(pid_file_cleanup); +} + int main(int argc, char *argv[]) { #ifdef CONFIG_POSIX @@ -326,6 +355,13 @@ int main(int argc, char *argv[]) qemu_init_main_loop(&error_fatal); process_options(argc, argv); + /* + * Write the pid file after creating chardevs, exports, and NBD servers but + * before accepting connections. This ordering is documented. Do not change + * it. + */ + pid_file_init(); + while (!exit_requested) { main_loop_wait(false); } -- cgit v1.2.3-55-g7522