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qemu-e2k/qga/main.c
Marc-André Lureau c98939daec qga: return a more explicit error on why a command is disabled 
qmp_disable_command() now takes an optional error string to return a
more explicit error message.

Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1928806

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
*fix up 80+ char line
Signed-off-by: Michael Roth <michael.roth@amd.com>
2021-03-16 20:21:47 -05:00

1555 lines
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/*
* QEMU Guest Agent
*
* Copyright IBM Corp. 2011
*
* Authors:
* Adam Litke <aglitke@linux.vnet.ibm.com>
* Michael Roth <mdroth@linux.vnet.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include <getopt.h>
#include <glib/gstdio.h>
#ifndef _WIN32
#include <syslog.h>
#include <sys/wait.h>
#endif
#include "qemu-common.h"
#include "qapi/qmp/json-parser.h"
#include "qapi/qmp/qdict.h"
#include "qapi/qmp/qjson.h"
#include "guest-agent-core.h"
#include "qga-qapi-init-commands.h"
#include "qapi/qmp/qerror.h"
#include "qapi/error.h"
#include "channel.h"
#include "qemu/bswap.h"
#include "qemu/cutils.h"
#include "qemu/help_option.h"
#include "qemu/sockets.h"
#include "qemu/systemd.h"
#include "qemu-version.h"
#ifdef _WIN32
#include <dbt.h>
#include "qga/service-win32.h"
#include "qga/vss-win32.h"
#endif
#ifdef __linux__
#include <linux/fs.h>
#ifdef FIFREEZE
#define CONFIG_FSFREEZE
#endif
#endif
#ifndef _WIN32
#define QGA_VIRTIO_PATH_DEFAULT "/dev/virtio-ports/org.qemu.guest_agent.0"
#define QGA_STATE_RELATIVE_DIR "run"
#define QGA_SERIAL_PATH_DEFAULT "/dev/ttyS0"
#else
#define QGA_VIRTIO_PATH_DEFAULT "\\\\.\\Global\\org.qemu.guest_agent.0"
#define QGA_STATE_RELATIVE_DIR "qemu-ga"
#define QGA_SERIAL_PATH_DEFAULT "COM1"
#endif
#ifdef CONFIG_FSFREEZE
#define QGA_FSFREEZE_HOOK_DEFAULT CONFIG_QEMU_CONFDIR "/fsfreeze-hook"
#endif
#define QGA_SENTINEL_BYTE 0xFF
#define QGA_CONF_DEFAULT CONFIG_QEMU_CONFDIR G_DIR_SEPARATOR_S "qemu-ga.conf"
#define QGA_RETRY_INTERVAL 5
static struct {
const char *state_dir;
const char *pidfile;
} dfl_pathnames;
typedef struct GAPersistentState {
#define QGA_PSTATE_DEFAULT_FD_COUNTER 1000
int64_t fd_counter;
} GAPersistentState;
typedef struct GAConfig GAConfig;
struct GAState {
JSONMessageParser parser;
GMainLoop *main_loop;
GAChannel *channel;
bool virtio; /* fastpath to check for virtio to deal with poll() quirks */
GACommandState *command_state;
GLogLevelFlags log_level;
FILE *log_file;
bool logging_enabled;
#ifdef _WIN32
GAService service;
HANDLE wakeup_event;
#endif
bool delimit_response;
bool frozen;
GList *blacklist;
char *state_filepath_isfrozen;
struct {
const char *log_filepath;
const char *pid_filepath;
} deferred_options;
#ifdef CONFIG_FSFREEZE
const char *fsfreeze_hook;
#endif
gchar *pstate_filepath;
GAPersistentState pstate;
GAConfig *config;
int socket_activation;
bool force_exit;
};
struct GAState *ga_state;
QmpCommandList ga_commands;
/* commands that are safe to issue while filesystems are frozen */
static const char *ga_freeze_whitelist[] = {
"guest-ping",
"guest-info",
"guest-sync",
"guest-sync-delimited",
"guest-fsfreeze-status",
"guest-fsfreeze-thaw",
NULL
};
#ifdef _WIN32
DWORD WINAPI service_ctrl_handler(DWORD ctrl, DWORD type, LPVOID data,
LPVOID ctx);
DWORD WINAPI handle_serial_device_events(DWORD type, LPVOID data);
VOID WINAPI service_main(DWORD argc, TCHAR *argv[]);
#endif
static int run_agent(GAState *s);
static void stop_agent(GAState *s, bool requested);
static void
init_dfl_pathnames(void)
{
g_assert(dfl_pathnames.state_dir == NULL);
g_assert(dfl_pathnames.pidfile == NULL);
dfl_pathnames.state_dir = qemu_get_local_state_pathname(
QGA_STATE_RELATIVE_DIR);
dfl_pathnames.pidfile = qemu_get_local_state_pathname(
QGA_STATE_RELATIVE_DIR G_DIR_SEPARATOR_S "qemu-ga.pid");
}
static void quit_handler(int sig)
{
/* if we're frozen, don't exit unless we're absolutely forced to,
* because it's basically impossible for graceful exit to complete
* unless all log/pid files are on unfreezable filesystems. there's
* also a very likely chance killing the agent before unfreezing
* the filesystems is a mistake (or will be viewed as one later).
* On Windows the freeze interval is limited to 10 seconds, so
* we should quit, but first we should wait for the timeout, thaw
* the filesystem and quit.
*/
if (ga_is_frozen(ga_state)) {
#ifdef _WIN32
int i = 0;
Error *err = NULL;
HANDLE hEventTimeout;
g_debug("Thawing filesystems before exiting");
hEventTimeout = OpenEvent(EVENT_ALL_ACCESS, FALSE, EVENT_NAME_TIMEOUT);
if (hEventTimeout) {
WaitForSingleObject(hEventTimeout, 0);
CloseHandle(hEventTimeout);
}
qga_vss_fsfreeze(&i, false, NULL, &err);
if (err) {
g_debug("Error unfreezing filesystems prior to exiting: %s",
error_get_pretty(err));
error_free(err);
}
#else
return;
#endif
}
g_debug("received signal num %d, quitting", sig);
stop_agent(ga_state, true);
}
#ifndef _WIN32
static gboolean register_signal_handlers(void)
{
struct sigaction sigact;
int ret;
memset(&sigact, 0, sizeof(struct sigaction));
sigact.sa_handler = quit_handler;
ret = sigaction(SIGINT, &sigact, NULL);
if (ret == -1) {
g_error("error configuring signal handler: %s", strerror(errno));
}
ret = sigaction(SIGTERM, &sigact, NULL);
if (ret == -1) {
g_error("error configuring signal handler: %s", strerror(errno));
}
sigact.sa_handler = SIG_IGN;
if (sigaction(SIGPIPE, &sigact, NULL) != 0) {
g_error("error configuring SIGPIPE signal handler: %s",
strerror(errno));
}
return true;
}
/* TODO: use this in place of all post-fork() fclose(std*) callers */
void reopen_fd_to_null(int fd)
{
int nullfd;
nullfd = open("/dev/null", O_RDWR);
if (nullfd < 0) {
return;
}
dup2(nullfd, fd);
if (nullfd != fd) {
close(nullfd);
}
}
#endif
static void usage(const char *cmd)
{
printf(
"Usage: %s [-m <method> -p <path>] [<options>]\n"
"QEMU Guest Agent " QEMU_FULL_VERSION "\n"
QEMU_COPYRIGHT "\n"
"\n"
" -m, --method transport method: one of unix-listen, virtio-serial,\n"
" isa-serial, or vsock-listen (virtio-serial is the default)\n"
" -p, --path device/socket path (the default for virtio-serial is:\n"
" %s,\n"
" the default for isa-serial is:\n"
" %s).\n"
" Socket addresses for vsock-listen are written as\n"
" <cid>:<port>.\n"
" -l, --logfile set logfile path, logs to stderr by default\n"
" -f, --pidfile specify pidfile (default is %s)\n"
#ifdef CONFIG_FSFREEZE
" -F, --fsfreeze-hook\n"
" enable fsfreeze hook. Accepts an optional argument that\n"
" specifies script to run on freeze/thaw. Script will be\n"
" called with 'freeze'/'thaw' arguments accordingly.\n"
" (default is %s)\n"
" If using -F with an argument, do not follow -F with a\n"
" space.\n"
" (for example: -F/var/run/fsfreezehook.sh)\n"
#endif
" -t, --statedir specify dir to store state information (absolute paths\n"
" only, default is %s)\n"
" -v, --verbose log extra debugging information\n"
" -V, --version print version information and exit\n"
" -d, --daemonize become a daemon\n"
#ifdef _WIN32
" -s, --service service commands: install, uninstall, vss-install, vss-uninstall\n"
#endif
" -b, --blacklist comma-separated list of RPCs to disable (no spaces, \"?\"\n"
" to list available RPCs)\n"
" -D, --dump-conf dump a qemu-ga config file based on current config\n"
" options / command-line parameters to stdout\n"
" -r, --retry-path attempt re-opening path if it's unavailable or closed\n"
" due to an error which may be recoverable in the future\n"
" (virtio-serial driver re-install, serial device hot\n"
" plug/unplug, etc.)\n"
" -h, --help display this help and exit\n"
"\n"
QEMU_HELP_BOTTOM "\n"
, cmd, QGA_VIRTIO_PATH_DEFAULT, QGA_SERIAL_PATH_DEFAULT,
dfl_pathnames.pidfile,
#ifdef CONFIG_FSFREEZE
QGA_FSFREEZE_HOOK_DEFAULT,
#endif
dfl_pathnames.state_dir);
}
static const char *ga_log_level_str(GLogLevelFlags level)
{
switch (level & G_LOG_LEVEL_MASK) {
case G_LOG_LEVEL_ERROR:
return "error";
case G_LOG_LEVEL_CRITICAL:
return "critical";
case G_LOG_LEVEL_WARNING:
return "warning";
case G_LOG_LEVEL_MESSAGE:
return "message";
case G_LOG_LEVEL_INFO:
return "info";
case G_LOG_LEVEL_DEBUG:
return "debug";
default:
return "user";
}
}
bool ga_logging_enabled(GAState *s)
{
return s->logging_enabled;
}
void ga_disable_logging(GAState *s)
{
s->logging_enabled = false;
}
void ga_enable_logging(GAState *s)
{
s->logging_enabled = true;
}
static void ga_log(const gchar *domain, GLogLevelFlags level,
const gchar *msg, gpointer opaque)
{
GAState *s = opaque;
GTimeVal time;
const char *level_str = ga_log_level_str(level);
if (!ga_logging_enabled(s)) {
return;
}
level &= G_LOG_LEVEL_MASK;
#ifndef _WIN32
if (g_strcmp0(domain, "syslog") == 0) {
syslog(LOG_INFO, "%s: %s", level_str, msg);
} else if (level & s->log_level) {
#else
if (level & s->log_level) {
#endif
g_get_current_time(&time);
fprintf(s->log_file,
"%lu.%lu: %s: %s\n", time.tv_sec, time.tv_usec, level_str, msg);
fflush(s->log_file);
}
}
void ga_set_response_delimited(GAState *s)
{
s->delimit_response = true;
}
static FILE *ga_open_logfile(const char *logfile)
{
FILE *f;
f = fopen(logfile, "a");
if (!f) {
return NULL;
}
qemu_set_cloexec(fileno(f));
return f;
}
static gint ga_strcmp(gconstpointer str1, gconstpointer str2)
{
return strcmp(str1, str2);
}
/* disable commands that aren't safe for fsfreeze */
static void ga_disable_non_whitelisted(const QmpCommand *cmd, void *opaque)
{
bool whitelisted = false;
int i = 0;
const char *name = qmp_command_name(cmd);
while (ga_freeze_whitelist[i] != NULL) {
if (strcmp(name, ga_freeze_whitelist[i]) == 0) {
whitelisted = true;
}
i++;
}
if (!whitelisted) {
g_debug("disabling command: %s", name);
qmp_disable_command(&ga_commands, name, "the agent is in frozen state");
}
}
/* [re-]enable all commands, except those explicitly blacklisted by user */
static void ga_enable_non_blacklisted(const QmpCommand *cmd, void *opaque)
{
GList *blacklist = opaque;
const char *name = qmp_command_name(cmd);
if (g_list_find_custom(blacklist, name, ga_strcmp) == NULL &&
!qmp_command_is_enabled(cmd)) {
g_debug("enabling command: %s", name);
qmp_enable_command(&ga_commands, name);
}
}
static bool ga_create_file(const char *path)
{
int fd = open(path, O_CREAT | O_WRONLY, S_IWUSR | S_IRUSR);
if (fd == -1) {
g_warning("unable to open/create file %s: %s", path, strerror(errno));
return false;
}
close(fd);
return true;
}
static bool ga_delete_file(const char *path)
{
int ret = unlink(path);
if (ret == -1) {
g_warning("unable to delete file: %s: %s", path, strerror(errno));
return false;
}
return true;
}
bool ga_is_frozen(GAState *s)
{
return s->frozen;
}
void ga_set_frozen(GAState *s)
{
if (ga_is_frozen(s)) {
return;
}
/* disable all non-whitelisted (for frozen state) commands */
qmp_for_each_command(&ga_commands, ga_disable_non_whitelisted, NULL);
g_warning("disabling logging due to filesystem freeze");
ga_disable_logging(s);
s->frozen = true;
if (!ga_create_file(s->state_filepath_isfrozen)) {
g_warning("unable to create %s, fsfreeze may not function properly",
s->state_filepath_isfrozen);
}
}
void ga_unset_frozen(GAState *s)
{
if (!ga_is_frozen(s)) {
return;
}
/* if we delayed creation/opening of pid/log files due to being
* in a frozen state at start up, do it now
*/
if (s->deferred_options.log_filepath) {
s->log_file = ga_open_logfile(s->deferred_options.log_filepath);
if (!s->log_file) {
s->log_file = stderr;
}
s->deferred_options.log_filepath = NULL;
}
ga_enable_logging(s);
g_warning("logging re-enabled due to filesystem unfreeze");
if (s->deferred_options.pid_filepath) {
Error *err = NULL;
if (!qemu_write_pidfile(s->deferred_options.pid_filepath, &err)) {
g_warning("%s", error_get_pretty(err));
error_free(err);
}
s->deferred_options.pid_filepath = NULL;
}
/* enable all disabled, non-blacklisted commands */
qmp_for_each_command(&ga_commands, ga_enable_non_blacklisted, s->blacklist);
s->frozen = false;
if (!ga_delete_file(s->state_filepath_isfrozen)) {
g_warning("unable to delete %s, fsfreeze may not function properly",
s->state_filepath_isfrozen);
}
}
#ifdef CONFIG_FSFREEZE
const char *ga_fsfreeze_hook(GAState *s)
{
return s->fsfreeze_hook;
}
#endif
static void become_daemon(const char *pidfile)
{
#ifndef _WIN32
pid_t pid, sid;
pid = fork();
if (pid < 0) {
exit(EXIT_FAILURE);
}
if (pid > 0) {
exit(EXIT_SUCCESS);
}
if (pidfile) {
Error *err = NULL;
if (!qemu_write_pidfile(pidfile, &err)) {
g_critical("%s", error_get_pretty(err));
error_free(err);
exit(EXIT_FAILURE);
}
}
umask(S_IRWXG | S_IRWXO);
sid = setsid();
if (sid < 0) {
goto fail;
}
if ((chdir("/")) < 0) {
goto fail;
}
reopen_fd_to_null(STDIN_FILENO);
reopen_fd_to_null(STDOUT_FILENO);
reopen_fd_to_null(STDERR_FILENO);
return;
fail:
if (pidfile) {
unlink(pidfile);
}
g_critical("failed to daemonize");
exit(EXIT_FAILURE);
#endif
}
static int send_response(GAState *s, const QDict *rsp)
{
GString *response;
GIOStatus status;
g_assert(s->channel);
if (!rsp) {
return 0;
}
response = qobject_to_json(QOBJECT(rsp));
if (!response) {
return -EINVAL;
}
if (s->delimit_response) {
s->delimit_response = false;
g_string_prepend_c(response, QGA_SENTINEL_BYTE);
}
g_string_append_c(response, '\n');
status = ga_channel_write_all(s->channel, response->str, response->len);
g_string_free(response, true);
if (status != G_IO_STATUS_NORMAL) {
return -EIO;
}
return 0;
}
/* handle requests/control events coming in over the channel */
static void process_event(void *opaque, QObject *obj, Error *err)
{
GAState *s = opaque;
QDict *rsp;
int ret;
g_debug("process_event: called");
assert(!obj != !err);
if (err) {
rsp = qmp_error_response(err);
goto end;
}
g_debug("processing command");
rsp = qmp_dispatch(&ga_commands, obj, false, NULL);
end:
ret = send_response(s, rsp);
if (ret < 0) {
g_warning("error sending error response: %s", strerror(-ret));
}
qobject_unref(rsp);
qobject_unref(obj);
}
/* false return signals GAChannel to close the current client connection */
static gboolean channel_event_cb(GIOCondition condition, gpointer data)
{
GAState *s = data;
gchar buf[QGA_READ_COUNT_DEFAULT + 1];
gsize count;
GIOStatus status = ga_channel_read(s->channel, buf, QGA_READ_COUNT_DEFAULT, &count);
switch (status) {
case G_IO_STATUS_ERROR:
g_warning("error reading channel");
stop_agent(s, false);
return false;
case G_IO_STATUS_NORMAL:
buf[count] = 0;
g_debug("read data, count: %d, data: %s", (int)count, buf);
json_message_parser_feed(&s->parser, (char *)buf, (int)count);
break;
case G_IO_STATUS_EOF:
g_debug("received EOF");
if (!s->virtio) {
return false;
}
/* fall through */
case G_IO_STATUS_AGAIN:
/* virtio causes us to spin here when no process is attached to
* host-side chardev. sleep a bit to mitigate this
*/
if (s->virtio) {
usleep(100 * 1000);
}
return true;
default:
g_warning("unknown channel read status, closing");
return false;
}
return true;
}
static gboolean channel_init(GAState *s, const gchar *method, const gchar *path,
int listen_fd)
{
GAChannelMethod channel_method;
if (strcmp(method, "virtio-serial") == 0) {
s->virtio = true; /* virtio requires special handling in some cases */
channel_method = GA_CHANNEL_VIRTIO_SERIAL;
} else if (strcmp(method, "isa-serial") == 0) {
channel_method = GA_CHANNEL_ISA_SERIAL;
} else if (strcmp(method, "unix-listen") == 0) {
channel_method = GA_CHANNEL_UNIX_LISTEN;
} else if (strcmp(method, "vsock-listen") == 0) {
channel_method = GA_CHANNEL_VSOCK_LISTEN;
} else {
g_critical("unsupported channel method/type: %s", method);
return false;
}
s->channel = ga_channel_new(channel_method, path, listen_fd,
channel_event_cb, s);
if (!s->channel) {
g_critical("failed to create guest agent channel");
return false;
}
return true;
}
#ifdef _WIN32
DWORD WINAPI handle_serial_device_events(DWORD type, LPVOID data)
{
DWORD ret = NO_ERROR;
PDEV_BROADCAST_HDR broadcast_header = (PDEV_BROADCAST_HDR)data;
if (broadcast_header->dbch_devicetype == DBT_DEVTYP_DEVICEINTERFACE) {
switch (type) {
/* Device inserted */
case DBT_DEVICEARRIVAL:
/* Start QEMU-ga's service */
if (!SetEvent(ga_state->wakeup_event)) {
ret = GetLastError();
}
break;
/* Device removed */
case DBT_DEVICEQUERYREMOVE:
case DBT_DEVICEREMOVEPENDING:
case DBT_DEVICEREMOVECOMPLETE:
/* Stop QEMU-ga's service */
if (!ResetEvent(ga_state->wakeup_event)) {
ret = GetLastError();
}
break;
default:
ret = ERROR_CALL_NOT_IMPLEMENTED;
}
}
return ret;
}
DWORD WINAPI service_ctrl_handler(DWORD ctrl, DWORD type, LPVOID data,
LPVOID ctx)
{
DWORD ret = NO_ERROR;
GAService *service = &ga_state->service;
switch (ctrl) {
case SERVICE_CONTROL_STOP:
case SERVICE_CONTROL_SHUTDOWN:
quit_handler(SIGTERM);
SetEvent(ga_state->wakeup_event);
service->status.dwCurrentState = SERVICE_STOP_PENDING;
SetServiceStatus(service->status_handle, &service->status);
break;
case SERVICE_CONTROL_DEVICEEVENT:
handle_serial_device_events(type, data);
break;
default:
ret = ERROR_CALL_NOT_IMPLEMENTED;
}
return ret;
}
VOID WINAPI service_main(DWORD argc, TCHAR *argv[])
{
GAService *service = &ga_state->service;
service->status_handle = RegisterServiceCtrlHandlerEx(QGA_SERVICE_NAME,
service_ctrl_handler, NULL);
if (service->status_handle == 0) {
g_critical("Failed to register extended requests function!\n");
return;
}
service->status.dwServiceType = SERVICE_WIN32;
service->status.dwCurrentState = SERVICE_RUNNING;
service->status.dwControlsAccepted = SERVICE_ACCEPT_STOP | SERVICE_ACCEPT_SHUTDOWN;
service->status.dwWin32ExitCode = NO_ERROR;
service->status.dwServiceSpecificExitCode = NO_ERROR;
service->status.dwCheckPoint = 0;
service->status.dwWaitHint = 0;
DEV_BROADCAST_DEVICEINTERFACE notification_filter;
ZeroMemory(&notification_filter, sizeof(notification_filter));
notification_filter.dbcc_devicetype = DBT_DEVTYP_DEVICEINTERFACE;
notification_filter.dbcc_size = sizeof(DEV_BROADCAST_DEVICEINTERFACE);
notification_filter.dbcc_classguid = GUID_VIOSERIAL_PORT;
service->device_notification_handle =
RegisterDeviceNotification(service->status_handle,
&notification_filter, DEVICE_NOTIFY_SERVICE_HANDLE);
if (!service->device_notification_handle) {
g_critical("Failed to register device notification handle!\n");
return;
}
SetServiceStatus(service->status_handle, &service->status);
run_agent(ga_state);
UnregisterDeviceNotification(service->device_notification_handle);
service->status.dwCurrentState = SERVICE_STOPPED;
SetServiceStatus(service->status_handle, &service->status);
}
#endif
static void set_persistent_state_defaults(GAPersistentState *pstate)
{
g_assert(pstate);
pstate->fd_counter = QGA_PSTATE_DEFAULT_FD_COUNTER;
}
static void persistent_state_from_keyfile(GAPersistentState *pstate,
GKeyFile *keyfile)
{
g_assert(pstate);
g_assert(keyfile);
/* if any fields are missing, either because the file was tampered with
* by agents of chaos, or because the field wasn't present at the time the
* file was created, the best we can ever do is start over with the default
* values. so load them now, and ignore any errors in accessing key-value
* pairs
*/
set_persistent_state_defaults(pstate);
if (g_key_file_has_key(keyfile, "global", "fd_counter", NULL)) {
pstate->fd_counter =
g_key_file_get_integer(keyfile, "global", "fd_counter", NULL);
}
}
static void persistent_state_to_keyfile(const GAPersistentState *pstate,
GKeyFile *keyfile)
{
g_assert(pstate);
g_assert(keyfile);
g_key_file_set_integer(keyfile, "global", "fd_counter", pstate->fd_counter);
}
static gboolean write_persistent_state(const GAPersistentState *pstate,
const gchar *path)
{
GKeyFile *keyfile = g_key_file_new();
GError *gerr = NULL;
gboolean ret = true;
gchar *data = NULL;
gsize data_len;
g_assert(pstate);
persistent_state_to_keyfile(pstate, keyfile);
data = g_key_file_to_data(keyfile, &data_len, &gerr);
if (gerr) {
g_critical("failed to convert persistent state to string: %s",
gerr->message);
ret = false;
goto out;
}
g_file_set_contents(path, data, data_len, &gerr);
if (gerr) {
g_critical("failed to write persistent state to %s: %s",
path, gerr->message);
ret = false;
goto out;
}
out:
if (gerr) {
g_error_free(gerr);
}
if (keyfile) {
g_key_file_free(keyfile);
}
g_free(data);
return ret;
}
static gboolean read_persistent_state(GAPersistentState *pstate,
const gchar *path, gboolean frozen)
{
GKeyFile *keyfile = NULL;
GError *gerr = NULL;
struct stat st;
gboolean ret = true;
g_assert(pstate);
if (stat(path, &st) == -1) {
/* it's okay if state file doesn't exist, but any other error
* indicates a permissions issue or some other misconfiguration
* that we likely won't be able to recover from.
*/
if (errno != ENOENT) {
g_critical("unable to access state file at path %s: %s",
path, strerror(errno));
ret = false;
goto out;
}
/* file doesn't exist. initialize state to default values and
* attempt to save now. (we could wait till later when we have
* modified state we need to commit, but if there's a problem,
* such as a missing parent directory, we want to catch it now)
*
* there is a potential scenario where someone either managed to
* update the agent from a version that didn't use a key store
* while qemu-ga thought the filesystem was frozen, or
* deleted the key store prior to issuing a fsfreeze, prior
* to restarting the agent. in this case we go ahead and defer
* initial creation till we actually have modified state to
* write, otherwise fail to recover from freeze.
*/
set_persistent_state_defaults(pstate);
if (!frozen) {
ret = write_persistent_state(pstate, path);
if (!ret) {
g_critical("unable to create state file at path %s", path);
ret = false;
goto out;
}
}
ret = true;
goto out;
}
keyfile = g_key_file_new();
g_key_file_load_from_file(keyfile, path, 0, &gerr);
if (gerr) {
g_critical("error loading persistent state from path: %s, %s",
path, gerr->message);
ret = false;
goto out;
}
persistent_state_from_keyfile(pstate, keyfile);
out:
if (keyfile) {
g_key_file_free(keyfile);
}
if (gerr) {
g_error_free(gerr);
}
return ret;
}
int64_t ga_get_fd_handle(GAState *s, Error **errp)
{
int64_t handle;
g_assert(s->pstate_filepath);
/* we blacklist commands and avoid operations that potentially require
* writing to disk when we're in a frozen state. this includes opening
* new files, so we should never get here in that situation
*/
g_assert(!ga_is_frozen(s));
handle = s->pstate.fd_counter++;
/* This should never happen on a reasonable timeframe, as guest-file-open
* would have to be issued 2^63 times */
if (s->pstate.fd_counter == INT64_MAX) {
abort();
}
if (!write_persistent_state(&s->pstate, s->pstate_filepath)) {
error_setg(errp, "failed to commit persistent state to disk");
return -1;
}
return handle;
}
static void ga_print_cmd(const QmpCommand *cmd, void *opaque)
{
printf("%s\n", qmp_command_name(cmd));
}
static GList *split_list(const gchar *str, const gchar *delim)
{
GList *list = NULL;
int i;
gchar **strv;
strv = g_strsplit(str, delim, -1);
for (i = 0; strv[i]; i++) {
list = g_list_prepend(list, strv[i]);
}
g_free(strv);
return list;
}
struct GAConfig {
char *channel_path;
char *method;
char *log_filepath;
char *pid_filepath;
#ifdef CONFIG_FSFREEZE
char *fsfreeze_hook;
#endif
char *state_dir;
#ifdef _WIN32
const char *service;
#endif
gchar *bliststr; /* blacklist may point to this string */
GList *blacklist;
int daemonize;
GLogLevelFlags log_level;
int dumpconf;
bool retry_path;
};
static void config_load(GAConfig *config)
{
GError *gerr = NULL;
GKeyFile *keyfile;
g_autofree char *conf = g_strdup(g_getenv("QGA_CONF")) ?: get_relocated_path(QGA_CONF_DEFAULT);
/* read system config */
keyfile = g_key_file_new();
if (!g_key_file_load_from_file(keyfile, conf, 0, &gerr)) {
goto end;
}
if (g_key_file_has_key(keyfile, "general", "daemon", NULL)) {
config->daemonize =
g_key_file_get_boolean(keyfile, "general", "daemon", &gerr);
}
if (g_key_file_has_key(keyfile, "general", "method", NULL)) {
config->method =
g_key_file_get_string(keyfile, "general", "method", &gerr);
}
if (g_key_file_has_key(keyfile, "general", "path", NULL)) {
config->channel_path =
g_key_file_get_string(keyfile, "general", "path", &gerr);
}
if (g_key_file_has_key(keyfile, "general", "logfile", NULL)) {
config->log_filepath =
g_key_file_get_string(keyfile, "general", "logfile", &gerr);
}
if (g_key_file_has_key(keyfile, "general", "pidfile", NULL)) {
config->pid_filepath =
g_key_file_get_string(keyfile, "general", "pidfile", &gerr);
}
#ifdef CONFIG_FSFREEZE
if (g_key_file_has_key(keyfile, "general", "fsfreeze-hook", NULL)) {
config->fsfreeze_hook =
g_key_file_get_string(keyfile,
"general", "fsfreeze-hook", &gerr);
}
#endif
if (g_key_file_has_key(keyfile, "general", "statedir", NULL)) {
config->state_dir =
g_key_file_get_string(keyfile, "general", "statedir", &gerr);
}
if (g_key_file_has_key(keyfile, "general", "verbose", NULL) &&
g_key_file_get_boolean(keyfile, "general", "verbose", &gerr)) {
/* enable all log levels */
config->log_level = G_LOG_LEVEL_MASK;
}
if (g_key_file_has_key(keyfile, "general", "retry-path", NULL)) {
config->retry_path =
g_key_file_get_boolean(keyfile, "general", "retry-path", &gerr);
}
if (g_key_file_has_key(keyfile, "general", "blacklist", NULL)) {
config->bliststr =
g_key_file_get_string(keyfile, "general", "blacklist", &gerr);
config->blacklist = g_list_concat(config->blacklist,
split_list(config->bliststr, ","));
}
end:
g_key_file_free(keyfile);
if (gerr &&
!(gerr->domain == G_FILE_ERROR && gerr->code == G_FILE_ERROR_NOENT)) {
g_critical("error loading configuration from path: %s, %s",
conf, gerr->message);
exit(EXIT_FAILURE);
}
g_clear_error(&gerr);
}
static gchar *list_join(GList *list, const gchar separator)
{
GString *str = g_string_new("");
while (list) {
str = g_string_append(str, (gchar *)list->data);
list = g_list_next(list);
if (list) {
str = g_string_append_c(str, separator);
}
}
return g_string_free(str, FALSE);
}
static void config_dump(GAConfig *config)
{
GError *error = NULL;
GKeyFile *keyfile;
gchar *tmp;
keyfile = g_key_file_new();
g_assert(keyfile);
g_key_file_set_boolean(keyfile, "general", "daemon", config->daemonize);
g_key_file_set_string(keyfile, "general", "method", config->method);
if (config->channel_path) {
g_key_file_set_string(keyfile, "general", "path", config->channel_path);
}
if (config->log_filepath) {
g_key_file_set_string(keyfile, "general", "logfile",
config->log_filepath);
}
g_key_file_set_string(keyfile, "general", "pidfile", config->pid_filepath);
#ifdef CONFIG_FSFREEZE
if (config->fsfreeze_hook) {
g_key_file_set_string(keyfile, "general", "fsfreeze-hook",
config->fsfreeze_hook);
}
#endif
g_key_file_set_string(keyfile, "general", "statedir", config->state_dir);
g_key_file_set_boolean(keyfile, "general", "verbose",
config->log_level == G_LOG_LEVEL_MASK);
g_key_file_set_boolean(keyfile, "general", "retry-path",
config->retry_path);
tmp = list_join(config->blacklist, ',');
g_key_file_set_string(keyfile, "general", "blacklist", tmp);
g_free(tmp);
tmp = g_key_file_to_data(keyfile, NULL, &error);
if (error) {
g_critical("Failed to dump keyfile: %s", error->message);
g_clear_error(&error);
} else {
printf("%s", tmp);
}
g_free(tmp);
g_key_file_free(keyfile);
}
static void config_parse(GAConfig *config, int argc, char **argv)
{
const char *sopt = "hVvdm:p:l:f:F::b:s:t:Dr";
int opt_ind = 0, ch;
const struct option lopt[] = {
{ "help", 0, NULL, 'h' },
{ "version", 0, NULL, 'V' },
{ "dump-conf", 0, NULL, 'D' },
{ "logfile", 1, NULL, 'l' },
{ "pidfile", 1, NULL, 'f' },
#ifdef CONFIG_FSFREEZE
{ "fsfreeze-hook", 2, NULL, 'F' },
#endif
{ "verbose", 0, NULL, 'v' },
{ "method", 1, NULL, 'm' },
{ "path", 1, NULL, 'p' },
{ "daemonize", 0, NULL, 'd' },
{ "blacklist", 1, NULL, 'b' },
#ifdef _WIN32
{ "service", 1, NULL, 's' },
#endif
{ "statedir", 1, NULL, 't' },
{ "retry-path", 0, NULL, 'r' },
{ NULL, 0, NULL, 0 }
};
while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
switch (ch) {
case 'm':
g_free(config->method);
config->method = g_strdup(optarg);
break;
case 'p':
g_free(config->channel_path);
config->channel_path = g_strdup(optarg);
break;
case 'l':
g_free(config->log_filepath);
config->log_filepath = g_strdup(optarg);
break;
case 'f':
g_free(config->pid_filepath);
config->pid_filepath = g_strdup(optarg);
break;
#ifdef CONFIG_FSFREEZE
case 'F':
g_free(config->fsfreeze_hook);
config->fsfreeze_hook = optarg ? g_strdup(optarg) : get_relocated_path(QGA_FSFREEZE_HOOK_DEFAULT);
break;
#endif
case 't':
g_free(config->state_dir);
config->state_dir = g_strdup(optarg);
break;
case 'v':
/* enable all log levels */
config->log_level = G_LOG_LEVEL_MASK;
break;
case 'V':
printf("QEMU Guest Agent %s\n", QEMU_VERSION);
exit(EXIT_SUCCESS);
case 'd':
config->daemonize = 1;
break;
case 'D':
config->dumpconf = 1;
break;
case 'r':
config->retry_path = true;
break;
case 'b': {
if (is_help_option(optarg)) {
qmp_for_each_command(&ga_commands, ga_print_cmd, NULL);
exit(EXIT_SUCCESS);
}
config->blacklist = g_list_concat(config->blacklist,
split_list(optarg, ","));
break;
}
#ifdef _WIN32
case 's':
config->service = optarg;
if (strcmp(config->service, "install") == 0) {
if (ga_install_vss_provider()) {
exit(EXIT_FAILURE);
}
if (ga_install_service(config->channel_path,
config->log_filepath, config->state_dir)) {
exit(EXIT_FAILURE);
}
exit(EXIT_SUCCESS);
} else if (strcmp(config->service, "uninstall") == 0) {
ga_uninstall_vss_provider();
exit(ga_uninstall_service());
} else if (strcmp(config->service, "vss-install") == 0) {
if (ga_install_vss_provider()) {
exit(EXIT_FAILURE);
}
exit(EXIT_SUCCESS);
} else if (strcmp(config->service, "vss-uninstall") == 0) {
ga_uninstall_vss_provider();
exit(EXIT_SUCCESS);
} else {
printf("Unknown service command.\n");
exit(EXIT_FAILURE);
}
break;
#endif
case 'h':
usage(argv[0]);
exit(EXIT_SUCCESS);
case '?':
g_print("Unknown option, try '%s --help' for more information.\n",
argv[0]);
exit(EXIT_FAILURE);
}
}
}
static void config_free(GAConfig *config)
{
g_free(config->method);
g_free(config->log_filepath);
g_free(config->pid_filepath);
g_free(config->state_dir);
g_free(config->channel_path);
g_free(config->bliststr);
#ifdef CONFIG_FSFREEZE
g_free(config->fsfreeze_hook);
#endif
g_list_free_full(config->blacklist, g_free);
g_free(config);
}
static bool check_is_frozen(GAState *s)
{
#ifndef _WIN32
/* check if a previous instance of qemu-ga exited with filesystems' state
* marked as frozen. this could be a stale value (a non-qemu-ga process
* or reboot may have since unfrozen them), but better to require an
* uneeded unfreeze than to risk hanging on start-up
*/
struct stat st;
if (stat(s->state_filepath_isfrozen, &st) == -1) {
/* it's okay if the file doesn't exist, but if we can't access for
* some other reason, such as permissions, there's a configuration
* that needs to be addressed. so just bail now before we get into
* more trouble later
*/
if (errno != ENOENT) {
g_critical("unable to access state file at path %s: %s",
s->state_filepath_isfrozen, strerror(errno));
return EXIT_FAILURE;
}
} else {
g_warning("previous instance appears to have exited with frozen"
" filesystems. deferring logging/pidfile creation and"
" disabling non-fsfreeze-safe commands until"
" guest-fsfreeze-thaw is issued, or filesystems are"
" manually unfrozen and the file %s is removed",
s->state_filepath_isfrozen);
return true;
}
#endif
return false;
}
static GAState *initialize_agent(GAConfig *config, int socket_activation)
{
GAState *s = g_new0(GAState, 1);
g_assert(ga_state == NULL);
s->log_level = config->log_level;
s->log_file = stderr;
#ifdef CONFIG_FSFREEZE
s->fsfreeze_hook = config->fsfreeze_hook;
#endif
s->pstate_filepath = g_strdup_printf("%s/qga.state", config->state_dir);
s->state_filepath_isfrozen = g_strdup_printf("%s/qga.state.isfrozen",
config->state_dir);
s->frozen = check_is_frozen(s);
g_log_set_default_handler(ga_log, s);
g_log_set_fatal_mask(NULL, G_LOG_LEVEL_ERROR);
ga_enable_logging(s);
#ifdef _WIN32
/* On win32 the state directory is application specific (be it the default
* or a user override). We got past the command line parsing; let's create
* the directory (with any intermediate directories). If we run into an
* error later on, we won't try to clean up the directory, it is considered
* persistent.
*/
if (g_mkdir_with_parents(config->state_dir, S_IRWXU) == -1) {
g_critical("unable to create (an ancestor of) the state directory"
" '%s': %s", config->state_dir, strerror(errno));
return NULL;
}
#endif
if (ga_is_frozen(s)) {
if (config->daemonize) {
/* delay opening/locking of pidfile till filesystems are unfrozen */
s->deferred_options.pid_filepath = config->pid_filepath;
become_daemon(NULL);
}
if (config->log_filepath) {
/* delay opening the log file till filesystems are unfrozen */
s->deferred_options.log_filepath = config->log_filepath;
}
ga_disable_logging(s);
qmp_for_each_command(&ga_commands, ga_disable_non_whitelisted, NULL);
} else {
if (config->daemonize) {
become_daemon(config->pid_filepath);
}
if (config->log_filepath) {
FILE *log_file = ga_open_logfile(config->log_filepath);
if (!log_file) {
g_critical("unable to open specified log file: %s",
strerror(errno));
return NULL;
}
s->log_file = log_file;
}
}
/* load persistent state from disk */
if (!read_persistent_state(&s->pstate,
s->pstate_filepath,
ga_is_frozen(s))) {
g_critical("failed to load persistent state");
return NULL;
}
config->blacklist = ga_command_blacklist_init(config->blacklist);
if (config->blacklist) {
GList *l = config->blacklist;
s->blacklist = config->blacklist;
do {
g_debug("disabling command: %s", (char *)l->data);
qmp_disable_command(&ga_commands, l->data, NULL);
l = g_list_next(l);
} while (l);
}
s->command_state = ga_command_state_new();
ga_command_state_init(s, s->command_state);
ga_command_state_init_all(s->command_state);
json_message_parser_init(&s->parser, process_event, s, NULL);
#ifndef _WIN32
if (!register_signal_handlers()) {
g_critical("failed to register signal handlers");
return NULL;
}
#endif
s->main_loop = g_main_loop_new(NULL, false);
s->config = config;
s->socket_activation = socket_activation;
#ifdef _WIN32
s->wakeup_event = CreateEvent(NULL, TRUE, FALSE, TEXT("WakeUp"));
if (s->wakeup_event == NULL) {
g_critical("CreateEvent failed");
return NULL;
}
#endif
ga_state = s;
return s;
}
static void cleanup_agent(GAState *s)
{
#ifdef _WIN32
CloseHandle(s->wakeup_event);
#endif
if (s->command_state) {
ga_command_state_cleanup_all(s->command_state);
ga_command_state_free(s->command_state);
json_message_parser_destroy(&s->parser);
}
g_free(s->pstate_filepath);
g_free(s->state_filepath_isfrozen);
if (s->main_loop) {
g_main_loop_unref(s->main_loop);
}
g_free(s);
ga_state = NULL;
}
static int run_agent_once(GAState *s)
{
if (!channel_init(s, s->config->method, s->config->channel_path,
s->socket_activation ? FIRST_SOCKET_ACTIVATION_FD : -1)) {
g_critical("failed to initialize guest agent channel");
return EXIT_FAILURE;
}
g_main_loop_run(ga_state->main_loop);
if (s->channel) {
ga_channel_free(s->channel);
}
return EXIT_SUCCESS;
}
static void wait_for_channel_availability(GAState *s)
{
g_warning("waiting for channel path...");
#ifndef _WIN32
sleep(QGA_RETRY_INTERVAL);
#else
DWORD dwWaitResult;
dwWaitResult = WaitForSingleObject(s->wakeup_event, INFINITE);
switch (dwWaitResult) {
case WAIT_OBJECT_0:
break;
case WAIT_TIMEOUT:
break;
default:
g_critical("WaitForSingleObject failed");
}
#endif
}
static int run_agent(GAState *s)
{
int ret = EXIT_SUCCESS;
s->force_exit = false;
do {
ret = run_agent_once(s);
if (s->config->retry_path && !s->force_exit) {
g_warning("agent stopped unexpectedly, restarting...");
wait_for_channel_availability(s);
}
} while (s->config->retry_path && !s->force_exit);
return ret;
}
static void stop_agent(GAState *s, bool requested)
{
if (!s->force_exit) {
s->force_exit = requested;
}
if (g_main_loop_is_running(s->main_loop)) {
g_main_loop_quit(s->main_loop);
}
}
int main(int argc, char **argv)
{
int ret = EXIT_SUCCESS;
GAState *s;
GAConfig *config = g_new0(GAConfig, 1);
int socket_activation;
config->log_level = G_LOG_LEVEL_ERROR | G_LOG_LEVEL_CRITICAL;
qemu_init_exec_dir(argv[0]);
qga_qmp_init_marshal(&ga_commands);
init_dfl_pathnames();
config_load(config);
config_parse(config, argc, argv);
if (config->pid_filepath == NULL) {
config->pid_filepath = g_strdup(dfl_pathnames.pidfile);
}
if (config->state_dir == NULL) {
config->state_dir = g_strdup(dfl_pathnames.state_dir);
}
if (config->method == NULL) {
config->method = g_strdup("virtio-serial");
}
socket_activation = check_socket_activation();
if (socket_activation > 1) {
g_critical("qemu-ga only supports listening on one socket");
ret = EXIT_FAILURE;
goto end;
}
if (socket_activation) {
SocketAddress *addr;
g_free(config->method);
g_free(config->channel_path);
config->method = NULL;
config->channel_path = NULL;
addr = socket_local_address(FIRST_SOCKET_ACTIVATION_FD, NULL);
if (addr) {
if (addr->type == SOCKET_ADDRESS_TYPE_UNIX) {
config->method = g_strdup("unix-listen");
} else if (addr->type == SOCKET_ADDRESS_TYPE_VSOCK) {
config->method = g_strdup("vsock-listen");
}
qapi_free_SocketAddress(addr);
}
if (!config->method) {
g_critical("unsupported listen fd type");
ret = EXIT_FAILURE;
goto end;
}
} else if (config->channel_path == NULL) {
if (strcmp(config->method, "virtio-serial") == 0) {
/* try the default path for the virtio-serial port */
config->channel_path = g_strdup(QGA_VIRTIO_PATH_DEFAULT);
} else if (strcmp(config->method, "isa-serial") == 0) {
/* try the default path for the serial port - COM1 */
config->channel_path = g_strdup(QGA_SERIAL_PATH_DEFAULT);
} else {
g_critical("must specify a path for this channel");
ret = EXIT_FAILURE;
goto end;
}
}
if (config->dumpconf) {
config_dump(config);
goto end;
}
s = initialize_agent(config, socket_activation);
if (!s) {
g_critical("error initializing guest agent");
goto end;
}
#ifdef _WIN32
if (config->daemonize) {
SERVICE_TABLE_ENTRY service_table[] = {
{ (char *)QGA_SERVICE_NAME, service_main }, { NULL, NULL } };
StartServiceCtrlDispatcher(service_table);
} else {
ret = run_agent(s);
}
#else
ret = run_agent(s);
#endif
cleanup_agent(s);
end:
if (config->daemonize) {
unlink(config->pid_filepath);
}
config_free(config);
return ret;
}
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