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qemu-e2k/qga/main.c
Markus Armbruster a903f40c31 qga: Use return values instead of error_is_set(errp) 
Using error_is_set(errp) to check whether a function call failed is
fragile: it breaks when errp is null.  ga_get_fd_handle() and
guest_file_handle_add() don't return a useful value when they fail,
but that's just stupid.  Fix that, and check them instead.  As far
as I can tell, errp can't be null there, but this is more robust and
more obviously correct.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-05-09 09:11:30 -04:00

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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 <stdlib.h>
#include <stdio.h>
#include <stdbool.h>
#include <glib.h>
#include <getopt.h>
#include <glib/gstdio.h>
#ifndef _WIN32
#include <syslog.h>
#include <sys/wait.h>
#include <sys/stat.h>
#endif
#include "qapi/qmp/json-streamer.h"
#include "qapi/qmp/json-parser.h"
#include "qapi/qmp/qint.h"
#include "qapi/qmp/qjson.h"
#include "qga/guest-agent-core.h"
#include "qemu/module.h"
#include "signal.h"
#include "qapi/qmp/qerror.h"
#include "qapi/qmp/dispatch.h"
#include "qga/channel.h"
#include "qemu/bswap.h"
#ifdef _WIN32
#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
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;
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;
#endif
bool delimit_response;
bool frozen;
GList *blacklist;
const char *state_filepath_isfrozen;
struct {
const char *log_filepath;
const char *pid_filepath;
} deferred_options;
#ifdef CONFIG_FSFREEZE
const char *fsfreeze_hook;
#endif
const gchar *pstate_filepath;
GAPersistentState pstate;
};
struct GAState *ga_state;
/* 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);
VOID WINAPI service_main(DWORD argc, TCHAR *argv[]);
#endif
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).
*/
if (ga_is_frozen(ga_state)) {
return;
}
g_debug("received signal num %d, quitting", sig);
if (g_main_loop_is_running(ga_state->main_loop)) {
g_main_loop_quit(ga_state->main_loop);
}
}
#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));
}
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 %s\n"
"\n"
" -m, --method transport method: one of unix-listen, virtio-serial, or\n"
" isa-serial (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"
" -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\n"
#endif
" -b, --blacklist comma-separated list of RPCs to disable (no spaces, \"?\"\n"
" to list available RPCs)\n"
" -h, --help display this help and exit\n"
"\n"
"Report bugs to <mdroth@linux.vnet.ibm.com>\n"
, cmd, QEMU_VERSION, 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 (domain && strcmp(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;
}
#ifndef _WIN32
static bool ga_open_pidfile(const char *pidfile)
{
int pidfd;
char pidstr[32];
pidfd = qemu_open(pidfile, O_CREAT|O_WRONLY, S_IRUSR|S_IWUSR);
if (pidfd == -1 || lockf(pidfd, F_TLOCK, 0)) {
g_critical("Cannot lock pid file, %s", strerror(errno));
if (pidfd != -1) {
close(pidfd);
}
return false;
}
if (ftruncate(pidfd, 0)) {
g_critical("Failed to truncate pid file");
goto fail;
}
snprintf(pidstr, sizeof(pidstr), "%d\n", getpid());
if (write(pidfd, pidstr, strlen(pidstr)) != strlen(pidstr)) {
g_critical("Failed to write pid file");
goto fail;
}
/* keep pidfile open & locked forever */
return true;
fail:
unlink(pidfile);
close(pidfd);
return false;
}
#else /* _WIN32 */
static bool ga_open_pidfile(const char *pidfile)
{
return true;
}
#endif
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(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(name);
}
}
/* [re-]enable all commands, except those explicitly blacklisted by user */
static void ga_enable_non_blacklisted(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(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_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) {
if (!ga_open_pidfile(s->deferred_options.pid_filepath)) {
g_warning("failed to create/open pid file");
}
s->deferred_options.pid_filepath = NULL;
}
/* enable all disabled, non-blacklisted commands */
qmp_for_each_command(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) {
if (!ga_open_pidfile(pidfile)) {
g_critical("failed to create pidfile");
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, QObject *payload)
{
const char *buf;
QString *payload_qstr, *response_qstr;
GIOStatus status;
g_assert(payload && s->channel);
payload_qstr = qobject_to_json(payload);
if (!payload_qstr) {
return -EINVAL;
}
if (s->delimit_response) {
s->delimit_response = false;
response_qstr = qstring_new();
qstring_append_chr(response_qstr, QGA_SENTINEL_BYTE);
qstring_append(response_qstr, qstring_get_str(payload_qstr));
QDECREF(payload_qstr);
} else {
response_qstr = payload_qstr;
}
qstring_append_chr(response_qstr, '\n');
buf = qstring_get_str(response_qstr);
status = ga_channel_write_all(s->channel, buf, strlen(buf));
QDECREF(response_qstr);
if (status != G_IO_STATUS_NORMAL) {
return -EIO;
}
return 0;
}
static void process_command(GAState *s, QDict *req)
{
QObject *rsp = NULL;
int ret;
g_assert(req);
g_debug("processing command");
rsp = qmp_dispatch(QOBJECT(req));
if (rsp) {
ret = send_response(s, rsp);
if (ret) {
g_warning("error sending response: %s", strerror(ret));
}
qobject_decref(rsp);
}
}
/* handle requests/control events coming in over the channel */
static void process_event(JSONMessageParser *parser, QList *tokens)
{
GAState *s = container_of(parser, GAState, parser);
QObject *obj;
QDict *qdict;
Error *err = NULL;
int ret;
g_assert(s && parser);
g_debug("process_event: called");
obj = json_parser_parse_err(tokens, NULL, &err);
if (err || !obj || qobject_type(obj) != QTYPE_QDICT) {
qobject_decref(obj);
qdict = qdict_new();
if (!err) {
g_warning("failed to parse event: unknown error");
error_set(&err, QERR_JSON_PARSING);
} else {
g_warning("failed to parse event: %s", error_get_pretty(err));
}
qdict_put_obj(qdict, "error", qmp_build_error_object(err));
error_free(err);
} else {
qdict = qobject_to_qdict(obj);
}
g_assert(qdict);
/* handle host->guest commands */
if (qdict_haskey(qdict, "execute")) {
process_command(s, qdict);
} else {
if (!qdict_haskey(qdict, "error")) {
QDECREF(qdict);
qdict = qdict_new();
g_warning("unrecognized payload format");
error_set(&err, QERR_UNSUPPORTED);
qdict_put_obj(qdict, "error", qmp_build_error_object(err));
error_free(err);
}
ret = send_response(s, QOBJECT(qdict));
if (ret) {
g_warning("error sending error response: %s", strerror(ret));
}
}
QDECREF(qdict);
}
/* 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;
GError *err = NULL;
GIOStatus status = ga_channel_read(s->channel, buf, QGA_READ_COUNT_DEFAULT, &count);
if (err != NULL) {
g_warning("error reading channel: %s", err->message);
g_error_free(err);
return false;
}
switch (status) {
case G_IO_STATUS_ERROR:
g_warning("error reading channel");
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)
{
GAChannelMethod channel_method;
if (method == NULL) {
method = "virtio-serial";
}
if (path == NULL) {
if (strcmp(method, "virtio-serial") == 0 ) {
/* try the default path for the virtio-serial port */
path = QGA_VIRTIO_PATH_DEFAULT;
} else if (strcmp(method, "isa-serial") == 0){
/* try the default path for the serial port - COM1 */
path = QGA_SERIAL_PATH_DEFAULT;
} else {
g_critical("must specify a path for this channel");
return false;
}
}
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 {
g_critical("unsupported channel method/type: %s", method);
return false;
}
s->channel = ga_channel_new(channel_method, path, channel_event_cb, s);
if (!s->channel) {
g_critical("failed to create guest agent channel");
return false;
}
return true;
}
#ifdef _WIN32
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);
service->status.dwCurrentState = SERVICE_STOP_PENDING;
SetServiceStatus(service->status_handle, &service->status);
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;
SetServiceStatus(service->status_handle, &service->status);
g_main_loop_run(ga_state->main_loop);
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(QmpCommand *cmd, void *opaque)
{
printf("%s\n", qmp_command_name(cmd));
}
int main(int argc, char **argv)
{
const char *sopt = "hVvdm:p:l:f:F::b:s:t:";
const char *method = NULL, *path = NULL;
const char *log_filepath = NULL;
const char *pid_filepath;
#ifdef CONFIG_FSFREEZE
const char *fsfreeze_hook = NULL;
#endif
const char *state_dir;
#ifdef _WIN32
const char *service = NULL;
#endif
const struct option lopt[] = {
{ "help", 0, NULL, 'h' },
{ "version", 0, NULL, 'V' },
{ "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' },
{ NULL, 0, NULL, 0 }
};
int opt_ind = 0, ch, daemonize = 0, i, j, len;
GLogLevelFlags log_level = G_LOG_LEVEL_ERROR | G_LOG_LEVEL_CRITICAL;
GList *blacklist = NULL;
GAState *s;
module_call_init(MODULE_INIT_QAPI);
init_dfl_pathnames();
pid_filepath = dfl_pathnames.pidfile;
state_dir = dfl_pathnames.state_dir;
while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
switch (ch) {
case 'm':
method = optarg;
break;
case 'p':
path = optarg;
break;
case 'l':
log_filepath = optarg;
break;
case 'f':
pid_filepath = optarg;
break;
#ifdef CONFIG_FSFREEZE
case 'F':
fsfreeze_hook = optarg ? optarg : QGA_FSFREEZE_HOOK_DEFAULT;
break;
#endif
case 't':
state_dir = optarg;
break;
case 'v':
/* enable all log levels */
log_level = G_LOG_LEVEL_MASK;
break;
case 'V':
printf("QEMU Guest Agent %s\n", QEMU_VERSION);
return 0;
case 'd':
daemonize = 1;
break;
case 'b': {
if (is_help_option(optarg)) {
qmp_for_each_command(ga_print_cmd, NULL);
return 0;
}
for (j = 0, i = 0, len = strlen(optarg); i < len; i++) {
if (optarg[i] == ',') {
optarg[i] = 0;
blacklist = g_list_append(blacklist, &optarg[j]);
j = i + 1;
}
}
if (j < i) {
blacklist = g_list_append(blacklist, &optarg[j]);
}
break;
}
#ifdef _WIN32
case 's':
service = optarg;
if (strcmp(service, "install") == 0) {
const char *fixed_state_dir;
/* If the user passed the "-t" option, we save that state dir
* in the service. Otherwise we let the service fetch the state
* dir from the environment when it starts.
*/
fixed_state_dir = (state_dir == dfl_pathnames.state_dir) ?
NULL :
state_dir;
if (ga_install_vss_provider()) {
return EXIT_FAILURE;
}
if (ga_install_service(path, log_filepath, fixed_state_dir)) {
return EXIT_FAILURE;
}
return 0;
} else if (strcmp(service, "uninstall") == 0) {
ga_uninstall_vss_provider();
return ga_uninstall_service();
} else {
printf("Unknown service command.\n");
return EXIT_FAILURE;
}
break;
#endif
case 'h':
usage(argv[0]);
return 0;
case '?':
g_print("Unknown option, try '%s --help' for more information.\n",
argv[0]);
return EXIT_FAILURE;
}
}
#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(state_dir, S_IRWXU) == -1) {
g_critical("unable to create (an ancestor of) the state directory"
" '%s': %s", state_dir, strerror(errno));
return EXIT_FAILURE;
}
#endif
s = g_malloc0(sizeof(GAState));
s->log_level = log_level;
s->log_file = stderr;
#ifdef CONFIG_FSFREEZE
s->fsfreeze_hook = fsfreeze_hook;
#endif
g_log_set_default_handler(ga_log, s);
g_log_set_fatal_mask(NULL, G_LOG_LEVEL_ERROR);
ga_enable_logging(s);
s->state_filepath_isfrozen = g_strdup_printf("%s/qga.state.isfrozen",
state_dir);
s->pstate_filepath = g_strdup_printf("%s/qga.state", state_dir);
s->frozen = false;
#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);
s->frozen = true;
}
#endif
if (ga_is_frozen(s)) {
if (daemonize) {
/* delay opening/locking of pidfile till filesystems are unfrozen */
s->deferred_options.pid_filepath = pid_filepath;
become_daemon(NULL);
}
if (log_filepath) {
/* delay opening the log file till filesystems are unfrozen */
s->deferred_options.log_filepath = log_filepath;
}
ga_disable_logging(s);
qmp_for_each_command(ga_disable_non_whitelisted, NULL);
} else {
if (daemonize) {
become_daemon(pid_filepath);
}
if (log_filepath) {
FILE *log_file = ga_open_logfile(log_filepath);
if (!log_file) {
g_critical("unable to open specified log file: %s",
strerror(errno));
goto out_bad;
}
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");
goto out_bad;
}
if (blacklist) {
s->blacklist = blacklist;
do {
g_debug("disabling command: %s", (char *)blacklist->data);
qmp_disable_command(blacklist->data);
blacklist = g_list_next(blacklist);
} while (blacklist);
}
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);
ga_state = s;
#ifndef _WIN32
if (!register_signal_handlers()) {
g_critical("failed to register signal handlers");
goto out_bad;
}
#endif
s->main_loop = g_main_loop_new(NULL, false);
if (!channel_init(ga_state, method, path)) {
g_critical("failed to initialize guest agent channel");
goto out_bad;
}
#ifndef _WIN32
g_main_loop_run(ga_state->main_loop);
#else
if (daemonize) {
SERVICE_TABLE_ENTRY service_table[] = {
{ (char *)QGA_SERVICE_NAME, service_main }, { NULL, NULL } };
StartServiceCtrlDispatcher(service_table);
} else {
g_main_loop_run(ga_state->main_loop);
}
#endif
ga_command_state_cleanup_all(ga_state->command_state);
ga_channel_free(ga_state->channel);
if (daemonize) {
unlink(pid_filepath);
}
return 0;
out_bad:
if (daemonize) {
unlink(pid_filepath);
}
return EXIT_FAILURE;
}
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