xemu/storage-daemon/qemu-storage-daemon.c
Hanna Reitz 9d8f8233b9 qsd: Unlink absolute PID file path
After writing the PID file, we register an atexit() handler 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 atexit() handler.

(realpath() needs a path pointing to an existing file, so we cannot use
it before qemu_write_pidfile().)

Reproducer:
$ cd /tmp
$ qemu-storage-daemon --daemonize --pidfile qsd.pid
$ file qsd.pid
qsd.pid: ASCII text
$ kill $(cat qsd.pid)
$ file qsd.pid
qsd.pid: ASCII text

(qsd.pid should be gone after the process has terminated.)

Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2092322
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220609122701.17172-2-hreitz@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2022-07-12 14:30:38 +02:00

447 lines
15 KiB
C

/*
* QEMU storage daemon
*
* Copyright (c) 2003-2008 Fabrice Bellard
* Copyright (c) 2019 Kevin Wolf <kwolf@redhat.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu/osdep.h"
#include <getopt.h>
#include "block/block.h"
#include "block/nbd.h"
#include "chardev/char.h"
#include "crypto/init.h"
#include "monitor/monitor.h"
#include "monitor/monitor-internal.h"
#include "qapi/error.h"
#include "qapi/qapi-visit-block-core.h"
#include "qapi/qapi-visit-block-export.h"
#include "qapi/qapi-visit-control.h"
#include "qapi/qmp/qdict.h"
#include "qapi/qmp/qstring.h"
#include "qapi/qobject-input-visitor.h"
#include "qemu/help-texts.h"
#include "qemu-version.h"
#include "qemu/cutils.h"
#include "qemu/config-file.h"
#include "qemu/error-report.h"
#include "qemu/help_option.h"
#include "qemu/log.h"
#include "qemu/main-loop.h"
#include "qemu/module.h"
#include "qemu/option.h"
#include "qom/object_interfaces.h"
#include "storage-daemon/qapi/qapi-commands.h"
#include "storage-daemon/qapi/qapi-init-commands.h"
#include "sysemu/runstate.h"
#include "trace/control.h"
static const char *pid_file;
static char *pid_file_realpath;
static volatile bool exit_requested = false;
void qemu_system_killed(int signal, pid_t pid)
{
exit_requested = true;
}
void qmp_quit(Error **errp)
{
exit_requested = true;
}
static void help(void)
{
printf(
"Usage: %s [options]\n"
"QEMU storage daemon\n"
"\n"
" -h, --help display this help and exit\n"
" -T, --trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
" specify tracing options\n"
" -V, --version output version information and exit\n"
"\n"
" --blockdev [driver=]<driver>[,node-name=<N>][,discard=ignore|unmap]\n"
" [,cache.direct=on|off][,cache.no-flush=on|off]\n"
" [,read-only=on|off][,auto-read-only=on|off]\n"
" [,force-share=on|off][,detect-zeroes=on|off|unmap]\n"
" [,driver specific parameters...]\n"
" configure a block backend\n"
"\n"
" --chardev <options> configure a character device backend\n"
" (see the qemu(1) man page for possible options)\n"
"\n"
" --daemonize daemonize the process, and have the parent exit\n"
" once startup is complete\n"
"\n"
" --export [type=]nbd,id=<id>,node-name=<node-name>[,name=<export-name>]\n"
" [,writable=on|off][,bitmap=<name>]\n"
" export the specified block node over NBD\n"
" (requires --nbd-server)\n"
"\n"
#ifdef CONFIG_FUSE
" --export [type=]fuse,id=<id>,node-name=<node-name>,mountpoint=<file>\n"
" [,growable=on|off][,writable=on|off][,allow-other=on|off|auto]\n"
" export the specified block node over FUSE\n"
"\n"
#endif /* CONFIG_FUSE */
#ifdef CONFIG_VHOST_USER_BLK_SERVER
" --export [type=]vhost-user-blk,id=<id>,node-name=<node-name>,\n"
" addr.type=unix,addr.path=<socket-path>[,writable=on|off]\n"
" [,logical-block-size=<block-size>][,num-queues=<num-queues>]\n"
" export the specified block node as a\n"
" vhost-user-blk device over UNIX domain socket\n"
" --export [type=]vhost-user-blk,id=<id>,node-name=<node-name>,\n"
" addr.type=fd,addr.str=<fd>[,writable=on|off]\n"
" [,logical-block-size=<block-size>][,num-queues=<num-queues>]\n"
" export the specified block node as a\n"
" vhost-user-blk device over file descriptor\n"
"\n"
#endif /* CONFIG_VHOST_USER_BLK_SERVER */
#ifdef CONFIG_VDUSE_BLK_EXPORT
" --export [type=]vduse-blk,id=<id>,node-name=<node-name>\n"
" ,name=<vduse-name>[,writable=on|off]\n"
" [,num-queues=<num-queues>][,queue-size=<queue-size>]\n"
" [,logical-block-size=<logical-block-size>]\n"
" [,serial=<serial-number>]\n"
" export the specified block node as a\n"
" vduse-blk device\n"
"\n"
#endif /* CONFIG_VDUSE_BLK_EXPORT */
" --monitor [chardev=]name[,mode=control][,pretty[=on|off]]\n"
" configure a QMP monitor\n"
"\n"
" --nbd-server addr.type=inet,addr.host=<host>,addr.port=<port>\n"
" [,tls-creds=<id>][,tls-authz=<id>][,max-connections=<n>]\n"
" --nbd-server addr.type=unix,addr.path=<path>\n"
" [,tls-creds=<id>][,tls-authz=<id>][,max-connections=<n>]\n"
" start an NBD server for exporting block nodes\n"
"\n"
" --object help list object types that can be added\n"
" --object <type>,help list properties for the given object type\n"
" --object <type>[,<property>=<value>...]\n"
" create a new object of type <type>, setting\n"
" properties in the order they are specified. Note\n"
" that the 'id' property must be set.\n"
" 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",
g_get_prgname());
}
enum {
OPTION_BLOCKDEV = 256,
OPTION_CHARDEV,
OPTION_DAEMONIZE,
OPTION_EXPORT,
OPTION_MONITOR,
OPTION_NBD_SERVER,
OPTION_OBJECT,
OPTION_PIDFILE,
};
extern QemuOptsList qemu_chardev_opts;
static void init_qmp_commands(void)
{
qmp_init_marshal(&qmp_commands);
QTAILQ_INIT(&qmp_cap_negotiation_commands);
qmp_register_command(&qmp_cap_negotiation_commands, "qmp_capabilities",
qmp_marshal_qmp_capabilities,
QCO_ALLOW_PRECONFIG, 0);
}
static int getopt_set_loc(int argc, char **argv, const char *optstring,
const struct option *longopts)
{
int c, save_index;
optarg = NULL;
save_index = optind;
c = getopt_long(argc, argv, optstring, longopts, NULL);
if (optarg) {
loc_set_cmdline(argv, save_index, MAX(1, optind - save_index));
}
return c;
}
/**
* Process QSD command-line arguments.
*
* This is done in two passes:
*
* First (@pre_init_pass is true), we do a pass where all global
* arguments pertaining to the QSD process (like --help or --daemonize)
* are processed. This pass is done before most of the QEMU-specific
* initialization steps (e.g. initializing the block layer or QMP), and
* so must only process arguments that are not really QEMU-specific.
*
* Second (@pre_init_pass is false), we (sequentially) process all
* QEMU/QSD-specific arguments. Many of these arguments are effectively
* translated to QMP commands (like --blockdev for blockdev-add, or
* --export for block-export-add).
*/
static void process_options(int argc, char *argv[], bool pre_init_pass)
{
int c;
static const struct option long_options[] = {
{"blockdev", required_argument, NULL, OPTION_BLOCKDEV},
{"chardev", required_argument, NULL, OPTION_CHARDEV},
{"daemonize", no_argument, NULL, OPTION_DAEMONIZE},
{"export", required_argument, NULL, OPTION_EXPORT},
{"help", no_argument, NULL, 'h'},
{"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}
};
/*
* In contrast to the system emulator, QEMU-specific options are processed
* in the order they are given on the command lines. This means that things
* must be defined first before they can be referenced in another option.
*/
optind = 1;
while ((c = getopt_set_loc(argc, argv, "-hT:V", long_options)) != -1) {
bool handle_option_pre_init;
/* Should this argument be processed in the pre-init pass? */
handle_option_pre_init =
c == '?' ||
c == 'h' ||
c == 'V' ||
c == OPTION_DAEMONIZE ||
c == OPTION_PIDFILE;
/* Process every option only in its respective pass */
if (pre_init_pass != handle_option_pre_init) {
continue;
}
switch (c) {
case '?':
exit(EXIT_FAILURE);
case 'h':
help();
exit(EXIT_SUCCESS);
case 'T':
trace_opt_parse(optarg);
trace_init_file();
break;
case 'V':
printf("qemu-storage-daemon version "
QEMU_FULL_VERSION "\n" QEMU_COPYRIGHT "\n");
exit(EXIT_SUCCESS);
case OPTION_BLOCKDEV:
{
Visitor *v;
BlockdevOptions *options;
v = qobject_input_visitor_new_str(optarg, "driver",
&error_fatal);
visit_type_BlockdevOptions(v, NULL, &options, &error_fatal);
visit_free(v);
qmp_blockdev_add(options, &error_fatal);
qapi_free_BlockdevOptions(options);
break;
}
case OPTION_CHARDEV:
{
/* TODO This interface is not stable until we QAPIfy it */
QemuOpts *opts = qemu_opts_parse_noisily(&qemu_chardev_opts,
optarg, true);
if (opts == NULL) {
exit(EXIT_FAILURE);
}
if (!qemu_chr_new_from_opts(opts, NULL, &error_fatal)) {
/* No error, but NULL returned means help was printed */
exit(EXIT_SUCCESS);
}
qemu_opts_del(opts);
break;
}
case OPTION_DAEMONIZE:
if (os_set_daemonize(true) < 0) {
/*
* --daemonize is parsed before monitor_init_globals_core(), so
* error_report() does not work yet
*/
fprintf(stderr, "--daemonize not supported in this build\n");
exit(EXIT_FAILURE);
}
break;
case OPTION_EXPORT:
{
Visitor *v;
BlockExportOptions *export;
v = qobject_input_visitor_new_str(optarg, "type", &error_fatal);
visit_type_BlockExportOptions(v, NULL, &export, &error_fatal);
visit_free(v);
qmp_block_export_add(export, &error_fatal);
qapi_free_BlockExportOptions(export);
break;
}
case OPTION_MONITOR:
{
Visitor *v;
MonitorOptions *monitor;
v = qobject_input_visitor_new_str(optarg, "chardev",
&error_fatal);
visit_type_MonitorOptions(v, NULL, &monitor, &error_fatal);
visit_free(v);
/* TODO Catch duplicate monitor IDs */
monitor_init(monitor, false, &error_fatal);
qapi_free_MonitorOptions(monitor);
break;
}
case OPTION_NBD_SERVER:
{
Visitor *v;
NbdServerOptions *options;
v = qobject_input_visitor_new_str(optarg, NULL, &error_fatal);
visit_type_NbdServerOptions(v, NULL, &options, &error_fatal);
visit_free(v);
nbd_server_start_options(options, &error_fatal);
qapi_free_NbdServerOptions(options);
break;
}
case OPTION_OBJECT:
user_creatable_process_cmdline(optarg);
break;
case OPTION_PIDFILE:
pid_file = optarg;
break;
case 1:
error_report("Unexpected argument");
exit(EXIT_FAILURE);
default:
g_assert_not_reached();
}
}
loc_set_none();
}
static void pid_file_cleanup(void)
{
unlink(pid_file_realpath);
}
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);
}
pid_file_realpath = g_malloc(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(EXIT_FAILURE);
}
atexit(pid_file_cleanup);
}
int main(int argc, char *argv[])
{
#ifdef CONFIG_POSIX
signal(SIGPIPE, SIG_IGN);
#endif
error_init(argv[0]);
qemu_init_exec_dir(argv[0]);
os_setup_signal_handling();
process_options(argc, argv, true);
os_daemonize();
module_call_init(MODULE_INIT_QOM);
module_call_init(MODULE_INIT_TRACE);
qemu_add_opts(&qemu_trace_opts);
qcrypto_init(&error_fatal);
bdrv_init();
monitor_init_globals_core();
init_qmp_commands();
if (!trace_init_backends()) {
return EXIT_FAILURE;
}
qemu_set_log(LOG_TRACE, &error_fatal);
qemu_init_main_loop(&error_fatal);
process_options(argc, argv, false);
/*
* 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();
os_setup_post();
while (!exit_requested) {
main_loop_wait(false);
}
blk_exp_close_all();
bdrv_drain_all_begin();
job_cancel_sync_all();
bdrv_close_all();
monitor_cleanup();
qemu_chr_cleanup();
user_creatable_cleanup();
return EXIT_SUCCESS;
}