/* * 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> #ifndef _WIN32 #include <syslog.h> #include <sys/wait.h> #include <sys/stat.h> #endif #include "json-streamer.h" #include "json-parser.h" #include "qint.h" #include "qjson.h" #include "qga/guest-agent-core.h" #include "module.h" #include "signal.h" #include "qerror.h" #include "qapi/qmp-core.h" #include "qga/channel.h" #ifdef _WIN32 #include "qga/service-win32.h" #include <windows.h> #endif #ifndef _WIN32 #define QGA_VIRTIO_PATH_DEFAULT "/dev/virtio-ports/org.qemu.guest_agent.0" #else #define QGA_VIRTIO_PATH_DEFAULT "\\\\.\\Global\\org.qemu.guest_agent.0" #endif #define QGA_STATEDIR_DEFAULT CONFIG_QEMU_LOCALSTATEDIR "/run" #define QGA_PIDFILE_DEFAULT QGA_STATEDIR_DEFAULT "/qemu-ga.pid" #define QGA_SENTINEL_BYTE 0xFF 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; }; 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-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 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" " -l, --logfile set logfile path, logs to stderr by default\n" " -f, --pidfile specify pidfile (default is %s)\n" " -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_PIDFILE_DEFAULT, QGA_STATEDIR_DEFAULT); } 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; } #ifndef _WIN32 static bool ga_open_pidfile(const char *pidfile) { int pidfd; char pidstr[32]; pidfd = 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) || lseek(pidfd, 0, SEEK_SET)) { 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; } return true; fail: unlink(pidfile); 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(void) { char **list_head, **list; bool whitelisted; int i; list_head = list = qmp_get_command_list(); while (*list != NULL) { whitelisted = false; i = 0; while (ga_freeze_whitelist[i] != NULL) { if (strcmp(*list, ga_freeze_whitelist[i]) == 0) { whitelisted = true; } i++; } if (!whitelisted) { g_debug("disabling command: %s", *list); qmp_disable_command(*list); } g_free(*list); list++; } g_free(list_head); } /* [re-]enable all commands, except those explicitly blacklisted by user */ static void ga_enable_non_blacklisted(GList *blacklist) { char **list_head, **list; list_head = list = qmp_get_command_list(); while (*list != NULL) { if (g_list_find_custom(blacklist, *list, ga_strcmp) == NULL && !qmp_command_is_enabled(*list)) { g_debug("enabling command: %s", *list); qmp_enable_command(*list); } g_free(*list); list++; } g_free(list_head); } 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 */ ga_disable_non_whitelisted(); 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 = fopen(s->deferred_options.log_filepath, "a"); 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 */ 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); } } 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(0); 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; } 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) { g_critical("must specify a path for this channel"); return false; } /* try the default path for the virtio-serial port */ path = QGA_VIRTIO_PATH_DEFAULT; } 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 int main(int argc, char **argv) { const char *sopt = "hVvdm:p:l:f:b:s:t:"; const char *method = NULL, *path = NULL; const char *log_filepath = NULL; const char *pid_filepath = QGA_PIDFILE_DEFAULT; const char *state_dir = QGA_STATEDIR_DEFAULT; #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' }, { "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); 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; 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': { char **list_head, **list; if (is_help_option(optarg)) { list_head = list = qmp_get_command_list(); while (*list != NULL) { printf("%s\n", *list); g_free(*list); list++; } g_free(list_head); 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) { return ga_install_service(path, log_filepath); } else if (strcmp(service, "uninstall") == 0) { 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; } } s = g_malloc0(sizeof(GAState)); s->log_level = log_level; s->log_file = stderr; 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->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 filesystem 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); ga_disable_non_whitelisted(); } else { if (daemonize) { become_daemon(pid_filepath); } if (log_filepath) { FILE *log_file = fopen(log_filepath, "a"); if (!log_file) { g_critical("unable to open specified log file: %s", strerror(errno)); goto out_bad; } s->log_file = log_file; } } 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; }