diff options
| -rw-r--r-- | docs/tools/qemu-storage-daemon.rst | 14 | ||||
| -rw-r--r-- | storage-daemon/qemu-storage-daemon.c | 36 |
2 files changed, 50 insertions, 0 deletions
diff --git a/docs/tools/qemu-storage-daemon.rst b/docs/tools/qemu-storage-daemon.rst index c05b3d3811..6ce85f2f7d 100644 --- a/docs/tools/qemu-storage-daemon.rst +++ b/docs/tools/qemu-storage-daemon.rst @@ -118,6 +118,20 @@ Standard options: List object properties with ``<type>,help``. See the :manpage:`qemu(1)` manual page for a description of the object properties. +.. option:: --pidfile PATH + + is the path to a file where the daemon writes its pid. This allows scripts to + stop the daemon by sending a signal:: + + $ kill -SIGTERM $(<path/to/qsd.pid) + + A file lock is applied to the file so only one instance of the daemon can run + with a given pid file path. The daemon unlinks its pid file when terminating. + + The pid file is written after chardevs, exports, and NBD servers have been + created but before accepting connections. The daemon has started successfully + when the pid file is written and clients may begin connecting. + Examples -------- Launch the daemon with QMP monitor socket ``qmp.sock`` so clients can execute 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 <path> 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); } |