/*
	 * Copyright 2004-2026 the Pacemaker project contributors
	 *
	 * The version control history for this file may have further details.
	 *
	 * This source code is licensed under the GNU Lesser General Public License
	 * version 2.1 or later (LGPLv2.1+) WITHOUT ANY WARRANTY.
	 */
	
	#include <crm_internal.h>
	
	#include <stdbool.h>
	#include <stdlib.h>
	#include <string.h>
	#include <signal.h>
	#include <errno.h>
	
	#include <sys/wait.h>
	
	#include <crm/crm.h>
	#include <crm/common/xml.h>
	#include <crm/common/mainloop.h>
	
	#include <qb/qbarray.h>
	
	struct trigger_s {
	    GSource source;
	    gboolean running;
	    gboolean trigger;
	    void *user_data;
	    unsigned int id;
	
	};
	
	struct mainloop_timer_s {
	        unsigned int id;
	        unsigned int period_ms;
	        bool repeat;
	        char *name;
	        GSourceFunc cb;
	        void *userdata;
	};
	
	static gboolean
	crm_trigger_prepare(GSource *source, int *timeout)
	{
	    crm_trigger_t *trig = (crm_trigger_t *) source;
	
	    /* cluster-glue's FD and IPC related sources make use of
	     * g_source_add_poll() but do not set a timeout in their prepare
	     * functions
	     *
	     * This means mainloop's poll() will block until an event for one
	     * of these sources occurs - any /other/ type of source, such as
	     * this one or g_idle_*, that doesn't use g_source_add_poll() is
	     * S-O-L and won't be processed until there is something fd-based
	     * happens.
	     *
	     * Luckily the timeout we can set here affects all sources and
	     * puts an upper limit on how long poll() can take.
	     *
	     * So unconditionally set a small-ish timeout, not too small that
	     * we're in constant motion, which will act as an upper bound on
	     * how long the signal handling might be delayed for.
	     */
	    *timeout = 500;             /* Timeout in ms */
	
	    return trig->trigger;
	}
	
	static gboolean
	crm_trigger_check(GSource * source)
	{
	    crm_trigger_t *trig = (crm_trigger_t *) source;
	
	    return trig->trigger;
	}
	
	/*!
	 * \internal
	 * \brief GSource dispatch function for crm_trigger_t
	 *
	 * \param[in] source        crm_trigger_t being dispatched
	 * \param[in] callback      Callback passed at source creation
	 * \param[in,out] userdata  User data passed at source creation
	 *
	 * \return G_SOURCE_REMOVE to remove source, G_SOURCE_CONTINUE to keep it
	 */
	static gboolean
	crm_trigger_dispatch(GSource *source, GSourceFunc callback, void *userdata)
	{
	    gboolean rc = G_SOURCE_CONTINUE;
	    crm_trigger_t *trig = (crm_trigger_t *) source;
	
	    if (trig->running) {
	        /* Wait until the existing job is complete before starting the next one */
	        return G_SOURCE_CONTINUE;
	    }
	    trig->trigger = FALSE;
	
	    if (callback) {
	        int callback_rc = callback(trig->user_data);
	
	        if (callback_rc < 0) {
	            pcmk__trace("Trigger handler %p not yet complete", trig);
	            trig->running = TRUE;
	        } else if (callback_rc == 0) {
	            rc = G_SOURCE_REMOVE;
	        }
	    }
	    return rc;
	}
	
	static void
	crm_trigger_finalize(GSource * source)
	{
	    pcmk__trace("Trigger %p destroyed", source);
	}
	
	static GSourceFuncs crm_trigger_funcs = {
	    crm_trigger_prepare,
	    crm_trigger_check,
	    crm_trigger_dispatch,
	    crm_trigger_finalize,
	};
	
	static crm_trigger_t *
	mainloop_setup_trigger(GSource * source, int priority,
	                       int (*dispatch)(void *user_data), void *userdata)
	{
	    crm_trigger_t *trigger = NULL;
	
	    trigger = (crm_trigger_t *) source;
	
	    trigger->id = 0;
	    trigger->trigger = FALSE;
	    trigger->user_data = userdata;
	
	    if (dispatch) {
	        g_source_set_callback(source, dispatch, trigger, NULL);
	    }
	
	    g_source_set_priority(source, priority);
	    g_source_set_can_recurse(source, FALSE);
	
	    trigger->id = g_source_attach(source, NULL);
	    return trigger;
	}
	
	void
	mainloop_trigger_complete(crm_trigger_t * trig)
	{
	    pcmk__trace("Trigger handler %p complete", trig);
	    trig->running = FALSE;
	}
	
	/*!
	 * \brief Create a trigger to be used as a mainloop source
	 *
	 * \param[in] priority  Relative priority of source (lower number is higher priority)
	 * \param[in] dispatch  Trigger dispatch function (should return 0 to remove the
	 *                      trigger from the mainloop, -1 if the trigger should be
	 *                      kept but the job is still running and not complete, and
	 *                      1 if the trigger should be kept and the job is complete)
	 * \param[in] userdata  Pointer to pass to \p dispatch
	 *
	 * \return Newly allocated mainloop source for trigger
	 */
	crm_trigger_t *
	mainloop_add_trigger(int priority, int (*dispatch) (void *user_data),
	                     void *userdata)
	{
	    GSource *source = NULL;
	
	    pcmk__assert(sizeof(crm_trigger_t) > sizeof(GSource));
	    source = g_source_new(&crm_trigger_funcs, sizeof(crm_trigger_t));
	
	    return mainloop_setup_trigger(source, priority, dispatch, userdata);
	}
	
	void
	mainloop_set_trigger(crm_trigger_t * source)
	{
	    if(source) {
	        source->trigger = TRUE;
	    }
	}
	
	gboolean
	mainloop_destroy_trigger(crm_trigger_t * source)
	{
	    GSource *gs = NULL;
	
	    if(source == NULL) {
	        return TRUE;
	    }
	
	    gs = (GSource *)source;
	
	    g_source_destroy(gs); /* Remove from mainloop, ref_count-- */
	    g_source_unref(gs); /* The caller no longer carries a reference to source
	                         *
	                         * At this point the source should be free'd,
	                         * unless we're currently processing said
	                         * source, in which case mainloop holds an
	                         * additional reference and it will be free'd
	                         * once our processing completes
	                         */
	    return TRUE;
	}
	
	// Define a custom glib source for signal handling
	
	// Data structure for custom glib source
	typedef struct {
	    crm_trigger_t trigger;      // trigger that invoked source (must be first)
	    void (*handler) (int sig);  // signal handler
	    int signal;                 // signal that was received
	} crm_signal_t;
	
	// Table to associate signal handlers with signal numbers
	static crm_signal_t *crm_signals[NSIG];
	
	/*!
	 * \internal
	 * \brief Dispatch an event from custom glib source for signals
	 *
	 * Given an signal event, clear the event trigger and call any registered
	 * signal handler.
	 *
	 * \param[in] source    glib source that triggered this dispatch
	 * \param[in] callback  (ignored)
	 * \param[in] userdata  (ignored)
	 */
	static gboolean
	crm_signal_dispatch(GSource *source, GSourceFunc callback, void *userdata)
	{
	    crm_signal_t *sig = (crm_signal_t *) source;
	
	    if(sig->signal != SIGCHLD) {
	        pcmk__notice("Caught '%s' signal " QB_XS " %d (%s handler)",
	                     strsignal(sig->signal), sig->signal,
	                     ((sig->handler != NULL)? "invoking" : "no"));
	    }
	
	    sig->trigger.trigger = FALSE;
	    if (sig->handler) {
	        sig->handler(sig->signal);
	    }
	    return TRUE;
	}
	
	/*!
	 * \internal
	 * \brief Handle a signal by setting a trigger for signal source
	 *
	 * \param[in] sig  Signal number that was received
	 *
	 * \note This is the true signal handler for the mainloop signal source, and
	 *       must be async-safe.
	 */
	static void
	mainloop_signal_handler(int sig)
	{
	    if (sig > 0 && sig < NSIG && crm_signals[sig] != NULL) {
	        mainloop_set_trigger((crm_trigger_t *) crm_signals[sig]);
	    }
	}
	
	// Functions implementing our custom glib source for signal handling
	static GSourceFuncs crm_signal_funcs = {
	    crm_trigger_prepare,
	    crm_trigger_check,
	    crm_signal_dispatch,
	    crm_trigger_finalize,
	};
	
	/*!
	 * \internal
	 * \brief Set a true signal handler
	 *
	 * signal()-like interface to sigaction()
	 *
	 * \param[in] sig       Signal number to register handler for
	 * \param[in] dispatch  Signal handler
	 *
	 * \return The previous value of the signal handler, or SIG_ERR on error
	 * \note The dispatch function must be async-safe.
	 */
	sighandler_t
	crm_signal_handler(int sig, sighandler_t dispatch)
	{
	    sigset_t mask;
	    struct sigaction sa;
	    struct sigaction old;
	
	    if (sigemptyset(&mask) < 0) {
	        pcmk__err("Could not %sset handler for signal %d: %s",
	                  ((dispatch == NULL)? "un" : ""), sig, strerror(errno));
	        return SIG_ERR;
	    }
	
	    memset(&sa, 0, sizeof(struct sigaction));
	    sa.sa_handler = dispatch;
	    sa.sa_flags = SA_RESTART;
	    sa.sa_mask = mask;
	
	    if (sigaction(sig, &sa, &old) < 0) {
	        pcmk__err("Could not %sset handler for signal %d: %s",
	                  ((dispatch == NULL)? "un" : ""), sig, strerror(errno));
	        return SIG_ERR;
	    }
	    return old.sa_handler;
	}
	
	static void
	mainloop_destroy_signal_entry(int sig)
	{
	    crm_signal_t *tmp = crm_signals[sig];
	
	    if (tmp != NULL) {
	        crm_signals[sig] = NULL;
	        pcmk__trace("Unregistering mainloop handler for signal %d", sig);
	        mainloop_destroy_trigger((crm_trigger_t *) tmp);
	    }
	}
	
	/*!
	 * \internal
	 * \brief Add a signal handler to a mainloop
	 *
	 * \param[in] sig       Signal number to handle
	 * \param[in] dispatch  Signal handler function (\c NULL to ignore the signal)
	 *
	 * \note The true signal handler merely sets a mainloop trigger to call this
	 *       dispatch function via the mainloop. Therefore, the dispatch function
	 *       does not need to be async-safe.
	 */
	gboolean
	mainloop_add_signal(int sig, void (*dispatch) (int sig))
	{
	    GSource *source = NULL;
	    int priority = G_PRIORITY_HIGH - 1;
	
	    if (sig == SIGTERM) {
	        /* TERM is higher priority than other signals,
	         *   signals are higher priority than other ipc.
	         * Yes, minus: smaller is "higher"
	         */
	        priority--;
	    }
	
	    if (sig >= NSIG || sig < 0) {
	        pcmk__err("Signal %d is out of range", sig);
	        return FALSE;
	
	    } else if (crm_signals[sig] != NULL && crm_signals[sig]->handler == dispatch) {
	        pcmk__trace("Signal handler for %d is already installed", sig);
	        return TRUE;
	
	    } else if (crm_signals[sig] != NULL) {
	        pcmk__err("Different signal handler for %d is already installed", sig);
	        return FALSE;
	    }
	
	    pcmk__assert(sizeof(crm_signal_t) > sizeof(GSource));
	    source = g_source_new(&crm_signal_funcs, sizeof(crm_signal_t));
	
	    crm_signals[sig] = (crm_signal_t *) mainloop_setup_trigger(source, priority, NULL, NULL);
	    pcmk__assert(crm_signals[sig] != NULL);
	
	    crm_signals[sig]->handler = dispatch;
	    crm_signals[sig]->signal = sig;
	
	    if (crm_signal_handler(sig, mainloop_signal_handler) == SIG_ERR) {
	        mainloop_destroy_signal_entry(sig);
	        return FALSE;
	    }
	
	    return TRUE;
	}
	
	gboolean
	mainloop_destroy_signal(int sig)
	{
	    if (sig >= NSIG || sig < 0) {
	        pcmk__err("Signal %d is out of range", sig);
	        return FALSE;
	
	    } else if (crm_signal_handler(sig, NULL) == SIG_ERR) {
	        // Error already logged
	        return FALSE;
	
	    } else if (crm_signals[sig] == NULL) {
	        return TRUE;
	    }
	    mainloop_destroy_signal_entry(sig);
	    return TRUE;
	}
	
	static qb_array_t *gio_map = NULL;
	
	void
	mainloop_cleanup(void)
	{
	    g_clear_pointer(&gio_map, qb_array_free);
	
	    for (int sig = 0; sig < NSIG; ++sig) {
	        mainloop_destroy_signal_entry(sig);
	    }
	}
	
	/*
	 * libqb...
	 */
	struct gio_to_qb_poll {
	    int32_t is_used;
	    unsigned int source;
	    int32_t events;
	    void *data;
	    qb_ipcs_dispatch_fn_t fn;
	    enum qb_loop_priority p;
	};
	
	static gboolean
	gio_read_socket(GIOChannel * gio, GIOCondition condition, void *data)
	{
	    struct gio_to_qb_poll *adaptor = (struct gio_to_qb_poll *)data;
	    int fd = g_io_channel_unix_get_fd(gio);
	
	    pcmk__trace("%p.%d %d", data, fd, condition);
	
	    /* if this assert get's hit, then there is a race condition between
	     * when we destroy a fd and when mainloop actually gives it up */
	    pcmk__assert(adaptor->is_used > 0);
	
	    return (adaptor->fn(fd, condition, adaptor->data) == 0);
	}
	
	static void
	gio_poll_destroy(void *data)
	{
	    struct gio_to_qb_poll *adaptor = (struct gio_to_qb_poll *)data;
	
	    adaptor->is_used--;
	    pcmk__assert(adaptor->is_used >= 0);
	
	    if (adaptor->is_used == 0) {
	        pcmk__trace("Marking adaptor %p unused", adaptor);
	        adaptor->source = 0;
	    }
	}
	
	/*!
	 * \internal
	 * \brief Convert libqb's poll priority into GLib's one
	 *
	 * \param[in] prio  libqb's poll priority (#QB_LOOP_MED assumed as fallback)
	 *
	 * \return  best matching GLib's priority
	 */
	static int
	conv_prio_libqb2glib(enum qb_loop_priority prio)
	{
	    switch (prio) {
	        case QB_LOOP_LOW:   return G_PRIORITY_LOW;
	        case QB_LOOP_HIGH:  return G_PRIORITY_HIGH;
	        default:            return G_PRIORITY_DEFAULT; // QB_LOOP_MED
	    }
	}
	
	/*!
	 * \internal
	 * \brief Convert libqb's poll priority to rate limiting spec
	 *
	 * \param[in] prio  libqb's poll priority (#QB_LOOP_MED assumed as fallback)
	 *
	 * \return  best matching rate limiting spec
	 * \note This is the inverse of libqb's qb_ipcs_request_rate_limit().
	 */
	static enum qb_ipcs_rate_limit
	conv_libqb_prio2ratelimit(enum qb_loop_priority prio)
	{
	    switch (prio) {
	        case QB_LOOP_LOW:   return QB_IPCS_RATE_SLOW;
	        case QB_LOOP_HIGH:  return QB_IPCS_RATE_FAST;
	        default:            return QB_IPCS_RATE_NORMAL; // QB_LOOP_MED
	    }
	}
	
	static int32_t
	gio_poll_dispatch_update(enum qb_loop_priority p, int32_t fd, int32_t evts,
	                         void *data, qb_ipcs_dispatch_fn_t fn, int32_t add)
	{
	    struct gio_to_qb_poll *adaptor;
	    GIOChannel *channel;
	    int32_t res = 0;
	
	    res = qb_array_index(gio_map, fd, (void **)&adaptor);
	    if (res < 0) {
	        pcmk__err("Array lookup failed for fd=%d: %d", fd, res);
	        return res;
	    }
	
	    pcmk__trace("Adding fd=%d to mainloop as adaptor %p", fd, adaptor);
	
	    if (add && adaptor->source) {
	        pcmk__err("Adaptor for descriptor %d is still in-use", fd);
	        return -EEXIST;
	    }
	    if (!add && !adaptor->is_used) {
	        pcmk__err("Adaptor for descriptor %d is not in-use", fd);
	        return -ENOENT;
	    }
	
	    /* channel is created with ref_count = 1 */
	    channel = g_io_channel_unix_new(fd);
	    if (!channel) {
	        pcmk__err("No memory left to add fd=%d", fd);
	        return -ENOMEM;
	    }
	
	    if (adaptor->source) {
	        g_source_remove(adaptor->source);
	        adaptor->source = 0;
	    }
	
	    /* Because unlike the poll() API, glib doesn't tell us about HUPs by default */
	    evts |= (G_IO_HUP | G_IO_NVAL | G_IO_ERR);
	
	    adaptor->fn = fn;
	    adaptor->events = evts;
	    adaptor->data = data;
	    adaptor->p = p;
	    adaptor->is_used++;
	    adaptor->source =
	        g_io_add_watch_full(channel, conv_prio_libqb2glib(p), evts,
	                            gio_read_socket, adaptor, gio_poll_destroy);
	
	    /* Now that mainloop now holds a reference to channel,
	     * thanks to g_io_add_watch_full(), drop ours from g_io_channel_unix_new().
	     *
	     * This means that channel will be free'd by:
	     * g_main_context_dispatch()
	     *  -> g_source_destroy_internal()
	     *      -> g_source_callback_unref()
	     * shortly after gio_poll_destroy() completes
	     */
	    g_io_channel_unref(channel);
	
	    pcmk__trace("Added to mainloop with gsource id=%d", adaptor->source);
	    if (adaptor->source > 0) {
	        return 0;
	    }
	
	    return -EINVAL;
	}
	
	static int32_t
	gio_poll_dispatch_add(enum qb_loop_priority p, int32_t fd, int32_t evts,
	                      void *data, qb_ipcs_dispatch_fn_t fn)
	{
	    return gio_poll_dispatch_update(p, fd, evts, data, fn, QB_TRUE);
	}
	
	static int32_t
	gio_poll_dispatch_mod(enum qb_loop_priority p, int32_t fd, int32_t evts,
	                      void *data, qb_ipcs_dispatch_fn_t fn)
	{
	    return gio_poll_dispatch_update(p, fd, evts, data, fn, QB_FALSE);
	}
	
	static int32_t
	gio_poll_dispatch_del(int32_t fd)
	{
	    struct gio_to_qb_poll *adaptor;
	
	    pcmk__trace("Looking for fd=%d", fd);
	    if (qb_array_index(gio_map, fd, (void **)&adaptor) == 0) {
	        if (adaptor->source) {
	            g_source_remove(adaptor->source);
	            adaptor->source = 0;
	        }
	    }
	    return 0;
	}
	
	struct qb_ipcs_poll_handlers gio_poll_funcs = {
	    .job_add = NULL,
	    .dispatch_add = gio_poll_dispatch_add,
	    .dispatch_mod = gio_poll_dispatch_mod,
	    .dispatch_del = gio_poll_dispatch_del,
	};
	
	static enum qb_ipc_type
	pick_ipc_type(enum qb_ipc_type requested)
	{
	    const char *env = pcmk__env_option(PCMK__ENV_IPC_TYPE);
	
	    if (env && strcmp("shared-mem", env) == 0) {
	        return QB_IPC_SHM;
	    } else if (env && strcmp("socket", env) == 0) {
	        return QB_IPC_SOCKET;
	    } else if (env && strcmp("posix", env) == 0) {
	        return QB_IPC_POSIX_MQ;
	    } else if (env && strcmp("sysv", env) == 0) {
	        return QB_IPC_SYSV_MQ;
	    } else if (requested == QB_IPC_NATIVE) {
	        /* We prefer shared memory because the server never blocks on
	         * send.  If part of a message fits into the socket, libqb
	         * needs to block until the remainder can be sent also.
	         * Otherwise the client will wait forever for the remaining
	         * bytes.
	         */
	        return QB_IPC_SHM;
	    }
	    return requested;
	}
	
	qb_ipcs_service_t *
	mainloop_add_ipc_server(const char *name, enum qb_ipc_type type,
	                        struct qb_ipcs_service_handlers *callbacks)
	{
	    return mainloop_add_ipc_server_with_prio(name, type, callbacks, QB_LOOP_MED);
	}
	
	qb_ipcs_service_t *
	mainloop_add_ipc_server_with_prio(const char *name, enum qb_ipc_type type,
	                                  struct qb_ipcs_service_handlers *callbacks,
	                                  enum qb_loop_priority prio)
	{
	    int rc = 0;
	    qb_ipcs_service_t *server = NULL;
	
	    if (gio_map == NULL) {
	        gio_map = qb_array_create_2(64, sizeof(struct gio_to_qb_poll), 1);
	    }
	
	    server = qb_ipcs_create(name, 0, pick_ipc_type(type), callbacks);
	
	    if (server == NULL) {
	        pcmk__err("Could not create %s IPC server: %s (%d)", name,
	                  pcmk_rc_str(errno), errno);
	        return NULL;
	    }
	
	    if (prio != QB_LOOP_MED) {
	        qb_ipcs_request_rate_limit(server, conv_libqb_prio2ratelimit(prio));
	    }
	
	    // Enforce a minimum IPC buffer size on all clients
	    qb_ipcs_enforce_buffer_size(server, crm_ipc_default_buffer_size());
	    qb_ipcs_poll_handlers_set(server, &gio_poll_funcs);
	
	    rc = qb_ipcs_run(server);
	    if (rc < 0) {
	        pcmk__err("Could not start %s IPC server: %s (%d)", name,
	                  pcmk_strerror(rc), rc);
	        return NULL; // qb_ipcs_run() destroys server on failure
	    }
	
	    return server;
	}
	
	void
	mainloop_del_ipc_server(qb_ipcs_service_t * server)
	{
	    if (server) {
	        qb_ipcs_destroy(server);
	    }
	}
	
	struct mainloop_io_s {
	    char *name;
	    void *userdata;
	
	    int fd;
	    unsigned int source;
	    crm_ipc_t *ipc;
	    GIOChannel *channel;
	
	    int (*dispatch_fn_ipc)(const char *buffer, ssize_t length, void *userdata);
	    int (*dispatch_fn_io)(void *userdata);
	    void (*destroy_fn)(void *userdata);
	};
	
	/*!
	 * \internal
	 * \brief I/O watch callback function (GIOFunc)
	 *
	 * \param[in] gio        I/O channel being watched
	 * \param[in] condition  I/O condition satisfied
	 * \param[in] data       User data passed when source was created
	 *
	 * \return G_SOURCE_REMOVE to remove source, G_SOURCE_CONTINUE to keep it
	 */
	static gboolean
	mainloop_gio_callback(GIOChannel *gio, GIOCondition condition, void *data)
	{
	    gboolean rc = G_SOURCE_CONTINUE;
	    mainloop_io_t *client = data;
	
	    pcmk__assert(client->fd == g_io_channel_unix_get_fd(gio));
	
	    if (condition & G_IO_IN) {
	        if (client->ipc) {
	            long read_rc = 0L;
	            int max = 10;
	
	            do {
	                read_rc = crm_ipc_read(client->ipc);
	                if (read_rc <= 0) {
	                    pcmk__trace("Could not read IPC message from %s: %s (%ld)",
	                                client->name, pcmk_strerror(read_rc), read_rc);
	
	                    if (read_rc == -EAGAIN) {
	                        continue;
	                    }
	
	                } else if (client->dispatch_fn_ipc) {
	                    const char *buffer = crm_ipc_buffer(client->ipc);
	
	                    pcmk__trace("New %ld-byte IPC message from %s after I/O "
	                                "condition %d",
	                                read_rc, client->name, (int) condition);
	                    if (client->dispatch_fn_ipc(buffer, read_rc, client->userdata) < 0) {
	                        pcmk__trace("Connection to %s no longer required",
	                                    client->name);
	                        rc = G_SOURCE_REMOVE;
	                    }
	                }
	
	                pcmk__ipc_free_client_buffer(client->ipc);
	
	            } while ((rc == G_SOURCE_CONTINUE) && (--max > 0)
	                      && ((read_rc > 0) || (read_rc == -EAGAIN)));
	
	        } else {
	            pcmk__trace("New I/O event for %s after I/O condition %d",
	                        client->name, (int) condition);
	            if (client->dispatch_fn_io) {
	                if (client->dispatch_fn_io(client->userdata) < 0) {
	                    pcmk__trace("Connection to %s no longer required",
	                                client->name);
	                    rc = G_SOURCE_REMOVE;
	                }
	            }
	        }
	    }
	
	    if (client->ipc && !crm_ipc_connected(client->ipc)) {
	        pcmk__err("Connection to %s closed " QB_XS " client=%p condition=%d",
	                  client->name, client, condition);
	        rc = G_SOURCE_REMOVE;
	
	    } else if (condition & (G_IO_HUP | G_IO_NVAL | G_IO_ERR)) {
	        pcmk__trace("The connection %s[%p] has been closed (I/O condition=%d)",
	                    client->name, client, condition);
	        rc = G_SOURCE_REMOVE;
	
	    } else if ((condition & G_IO_IN) == 0) {
	        /*
	           #define      GLIB_SYSDEF_POLLIN     =1
	           #define      GLIB_SYSDEF_POLLPRI    =2
	           #define      GLIB_SYSDEF_POLLOUT    =4
	           #define      GLIB_SYSDEF_POLLERR    =8
	           #define      GLIB_SYSDEF_POLLHUP    =16
	           #define      GLIB_SYSDEF_POLLNVAL   =32
	
	           typedef enum
	           {
	           G_IO_IN      GLIB_SYSDEF_POLLIN,
	           G_IO_OUT     GLIB_SYSDEF_POLLOUT,
	           G_IO_PRI     GLIB_SYSDEF_POLLPRI,
	           G_IO_ERR     GLIB_SYSDEF_POLLERR,
	           G_IO_HUP     GLIB_SYSDEF_POLLHUP,
	           G_IO_NVAL    GLIB_SYSDEF_POLLNVAL
	           } GIOCondition;
	
	           A bitwise combination representing a condition to watch for on an event source.
	
	           G_IO_IN      There is data to read.
	           G_IO_OUT     Data can be written (without blocking).
	           G_IO_PRI     There is urgent data to read.
	           G_IO_ERR     Error condition.
	           G_IO_HUP     Hung up (the connection has been broken, usually for pipes and sockets).
	           G_IO_NVAL    Invalid request. The file descriptor is not open.
	         */
	        pcmk__err("Strange condition: %d", condition);
	    }
	
	    /* G_SOURCE_REMOVE results in mainloop_gio_destroy() being called
	     * just before the source is removed from mainloop
	     */
	    return rc;
	}
	
	static void

	mainloop_gio_destroy(void *c)
	{
	    mainloop_io_t *client = c;
	    char *c_name = strdup(client->name);
	
	    /* client->source is valid but about to be destroyed (ref_count == 0) in gmain.c
	     * client->channel will still have ref_count > 0... should be == 1
	     */
	    pcmk__trace("Destroying client %s[%p]", c_name, c);
	
	    if (client->ipc) {
	        crm_ipc_close(client->ipc);
	    }
	
	    if (client->destroy_fn) {
	        void (*destroy_fn)(void *userdata) = client->destroy_fn;
	
	        client->destroy_fn = NULL;
	        destroy_fn(client->userdata);
	    }
	
	    if (client->ipc) {
	        crm_ipc_t *ipc = client->ipc;
	
	        client->ipc = NULL;
	        crm_ipc_destroy(ipc);
	    }
	
	    pcmk__trace("Destroyed client %s[%p]", c_name, c);
	
	    free(client->name);
	    free(client);
	
	    free(c_name);
	}
	
	/*!
	 * \brief Connect to IPC and add it as a main loop source
	 *
	 * \param[in,out] ipc        IPC connection to add
	 * \param[in]     priority   Event source priority to use for connection
	 * \param[in]     userdata   Data to register with callbacks
	 * \param[in]     callbacks  Dispatch and destroy callbacks for connection
	 * \param[out]    source     Newly allocated event source
	 *
	 * \return Standard Pacemaker return code
	 *
	 * \note On failure, the caller is still responsible for ipc. On success, the
	 *       caller should call mainloop_del_ipc_client() when source is no longer
	 *       needed, which will lead to the disconnection of the IPC later in the
	 *       main loop if it is connected. However the IPC disconnects,
	 *       mainloop_gio_destroy() will free ipc and source after calling the
	 *       destroy callback.
	 */
	int
	pcmk__add_mainloop_ipc(crm_ipc_t *ipc, int priority, void *userdata,
	                       const struct ipc_client_callbacks *callbacks,
	                       mainloop_io_t **source)
	{
	    int rc = pcmk_rc_ok;
	    int fd = -1;
	    const char *ipc_name = NULL;
	
	    CRM_CHECK((ipc != NULL) && (callbacks != NULL), return EINVAL);
	
	    ipc_name = pcmk__s(crm_ipc_name(ipc), "Pacemaker");
	    rc = pcmk__connect_generic_ipc(ipc);
	    if (rc != pcmk_rc_ok) {
	        pcmk__debug("Connection to %s failed: %s", ipc_name, pcmk_rc_str(rc));
	        return rc;
	    }
	
	    rc = pcmk__ipc_fd(ipc, &fd);
	    if (rc != pcmk_rc_ok) {
	        pcmk__debug("Could not obtain file descriptor for %s IPC: %s", ipc_name,
	                    pcmk_rc_str(rc));
	        crm_ipc_close(ipc);
	        return rc;
	    }
	
	    *source = mainloop_add_fd(ipc_name, priority, fd, userdata, NULL);
	    if (*source == NULL) {
	        rc = errno;
	        crm_ipc_close(ipc);
	        return rc;
	    }
	
	    (*source)->ipc = ipc;
	    (*source)->destroy_fn = callbacks->destroy;
	    (*source)->dispatch_fn_ipc = callbacks->dispatch;
	    return pcmk_rc_ok;
	}
	
	/*!
	 * \brief Get period for mainloop timer
	 *
	 * \param[in]  timer      Timer
	 *
	 * \return Period in ms
	 */
	unsigned int
	pcmk__mainloop_timer_get_period(const mainloop_timer_t *timer)
	{
	    if (timer) {
	        return timer->period_ms;
	    }
	    return 0;
	}
	
	mainloop_io_t *
	mainloop_add_ipc_client(const char *name, int priority, size_t max_size,
	                        void *userdata, struct ipc_client_callbacks *callbacks)
	{
	    crm_ipc_t *ipc = crm_ipc_new(name, 0);
	    mainloop_io_t *source = NULL;
	    int rc = pcmk__add_mainloop_ipc(ipc, priority, userdata, callbacks,
	                                    &source);
	
	    if (rc != pcmk_rc_ok) {
	        if (crm_log_level == PCMK__LOG_STDOUT) {
	            fprintf(stderr, "Connection to %s failed: %s",
	                    name, pcmk_rc_str(rc));
	        }
	        crm_ipc_destroy(ipc);
	        if (rc > 0) {
	            errno = rc;
	        } else {
	            errno = ENOTCONN;
	        }
	        return NULL;
	    }
	    return source;
	}
	
	void
	mainloop_del_ipc_client(mainloop_io_t * client)
	{
	    mainloop_del_fd(client);
	}
	
	crm_ipc_t *
	mainloop_get_ipc_client(mainloop_io_t * client)
	{
	    if (client) {
	        return client->ipc;
	    }
	    return NULL;
	}
	
	mainloop_io_t *
	mainloop_add_fd(const char *name, int priority, int fd, void *userdata,
	                struct mainloop_fd_callbacks * callbacks)
	{
	    mainloop_io_t *client = NULL;
	
	    if (fd >= 0) {
	        client = calloc(1, sizeof(mainloop_io_t));
	        if (client == NULL) {
	            return NULL;
	        }
	        client->name = strdup(name);
	        client->userdata = userdata;
	
	        if (callbacks) {
	            client->destroy_fn = callbacks->destroy;
	            client->dispatch_fn_io = callbacks->dispatch;
	        }
	
	        client->fd = fd;

	        client->channel = g_io_channel_unix_new(fd);
	        client->source =
	            g_io_add_watch_full(client->channel, priority,
	                                (G_IO_IN | G_IO_HUP | G_IO_NVAL | G_IO_ERR), mainloop_gio_callback,
	                                client, mainloop_gio_destroy);
	
	        /* Now that mainloop now holds a reference to channel,
	         * thanks to g_io_add_watch_full(), drop ours from g_io_channel_unix_new().
	         *
	         * This means that channel will be free'd by:
	         * g_main_context_dispatch() or g_source_remove()
	         *  -> g_source_destroy_internal()
	         *      -> g_source_callback_unref()
	         * shortly after mainloop_gio_destroy() completes
	         */
	        g_io_channel_unref(client->channel);
	        pcmk__trace("Added connection %d for %s[%p].%d", client->source,
	                    client->name, client, fd);
	    } else {
	        errno = EINVAL;
	    }
	
	    return client;
	}
	
	void
	mainloop_del_fd(mainloop_io_t *client)
	{
	    if ((client == NULL) || (client->source == 0)) {
	        return;
	    }
	
	    pcmk__trace("Removing client %s[%p]", client->name, client);
	
	    // mainloop_gio_destroy() gets called during source removal
	    g_source_remove(client->source);
	}
	
	static GList *child_list = NULL;
	
	pid_t
	mainloop_child_pid(mainloop_child_t * child)
	{
	    return child->pid;
	}
	
	const char *
	mainloop_child_name(mainloop_child_t * child)
	{
	    return child->desc;
	}
	
	int
	mainloop_child_timeout(mainloop_child_t * child)
	{
	    return child->timeout;
	}
	
	void *
	mainloop_child_userdata(mainloop_child_t * child)
	{
	    return child->privatedata;
	}
	
	void
	mainloop_clear_child_userdata(mainloop_child_t * child)
	{
	    child->privatedata = NULL;
	}
	
	/* good function name */
	static void
	child_free(mainloop_child_t *child)
	{
	    if (child->timerid != 0) {
	        pcmk__trace("Removing timer %d", child->timerid);
	        g_source_remove(child->timerid);
	        child->timerid = 0;
	    }
	    free(child->desc);
	    free(child);
	}
	
	/* terrible function name */
	static int
	child_kill_helper(mainloop_child_t *child)
	{
	    int rc;
	    if (child->flags & mainloop_leave_pid_group) {
	        pcmk__debug("Killing PID %lld only. Leaving its process group intact.",
	                    (long long) child->pid);
	        rc = kill(child->pid, SIGKILL);
	    } else {
	        pcmk__debug("Killing PID %lld's entire process group",
	                    (long long) child->pid);
	        rc = kill(-child->pid, SIGKILL);
	    }
	
	    if (rc < 0) {
	        if (errno != ESRCH) {
	            pcmk__err("kill(%d, KILL) failed: %s", child->pid, strerror(errno));
	        }
	        return -errno;
	    }
	    return 0;
	}
	
	static gboolean
	child_timeout_callback(void *p)
	{
	    mainloop_child_t *child = p;
	    int rc = 0;
	
	    child->timerid = 0;
	    if (child->timeout) {
	        pcmk__warn("%s process (PID %lld) will not die!", child->desc,
	                   (long long) child->pid);
	        return FALSE;
	    }
	
	    rc = child_kill_helper(child);
	    if (rc == -ESRCH) {
	        /* Nothing left to do. pid doesn't exist */
	        return FALSE;
	    }
	
	    child->timeout = TRUE;
	    pcmk__debug("%s process (PID %lld) timed out", child->desc,
	                (long long) child->pid);
	
	    child->timerid = pcmk__create_timer(5000, child_timeout_callback, child);
	    return FALSE;
	}
	
	static bool
	child_waitpid(mainloop_child_t *child, int flags)
	{
	    int rc = 0;
	    int core = 0;
	    int signo = 0;
	    int status = 0;
	    int exitcode = 0;
	    bool callback_needed = true;
	
	    rc = waitpid(child->pid, &status, flags);
	    if (rc == 0) { // WNOHANG in flags, and child status is not available
	        pcmk__trace("Child process %lld (%s) still active",
	                    (long long) child->pid, child->desc);
	        callback_needed = false;
	
	    } else if (rc != child->pid) {
	        /* According to POSIX, possible conditions:
	         * - child->pid was non-positive (process group or any child),
	         *   and rc is specific child
	         * - errno ECHILD (pid does not exist or is not child)
	         * - errno EINVAL (invalid flags)
	         * - errno EINTR (caller interrupted by signal)
	         *
	         * @TODO Handle these cases more specifically.
	         */
	        signo = SIGCHLD;
	        exitcode = 1;
	        pcmk__notice("Wait for child process %d (%s) interrupted: %s",
	                     child->pid, child->desc, pcmk_rc_str(errno));
	
	    } else if (WIFEXITED(status)) {
	        exitcode = WEXITSTATUS(status);
	        pcmk__trace("Child process %lld (%s) exited with status %d",
	                    (long long) child->pid, child->desc, exitcode);
	
	    } else if (WIFSIGNALED(status)) {
	        signo = WTERMSIG(status);
	        pcmk__trace("Child process %lld (%s) exited with signal %d (%s)",
	                    (long long) child->pid, child->desc, signo,
	                    strsignal(signo));
	
	#ifdef WCOREDUMP // AIX, SunOS, maybe others
	    } else if (WCOREDUMP(status)) {
	        core = 1;
	        pcmk__err("Child process %d (%s) dumped core", child->pid, child->desc);
	#endif
	
	    } else { // flags must contain WUNTRACED and/or WCONTINUED to reach this
	        pcmk__trace("Child process %lld (%s) stopped or continued",
	                    (long long) child->pid, child->desc);
	        callback_needed = false;
	    }
	
	    if (callback_needed && child->exit_fn) {
	        child->exit_fn(child, core, signo, exitcode);
	    }
	    return callback_needed;
	}
	
	static void
	child_death_dispatch(int signal)
	{
	    for (GList *iter = child_list; iter; ) {
	        GList *saved = iter;
	        mainloop_child_t *child = iter->data;
	
	        iter = iter->next;
	        if (child_waitpid(child, WNOHANG)) {
	            pcmk__trace("Removing completed process %lld from child list",
	                        (long long) child->pid);
	            child_list = g_list_remove_link(child_list, saved);
	            g_list_free(saved);
	            child_free(child);
	        }
	    }
	}
	
	static gboolean
	child_signal_init(void *p)
	{
	    pcmk__trace("Installed SIGCHLD handler");
	    /* Do NOT use g_child_watch_add() and friends, they rely on pthreads */
	    mainloop_add_signal(SIGCHLD, child_death_dispatch);
	
	    /* In case they terminated before the signal handler was installed */
	    child_death_dispatch(SIGCHLD);
	    return FALSE;
	}
	
	gboolean
	mainloop_child_kill(pid_t pid)
	{
	    GList *iter;
	    mainloop_child_t *child = NULL;
	    mainloop_child_t *match = NULL;
	    /* It is impossible to block SIGKILL, this allows us to
	     * call waitpid without WNOHANG flag.*/
	    int waitflags = 0, rc = 0;
	
	    for (iter = child_list; iter != NULL && match == NULL; iter = iter->next) {
	        child = iter->data;
	        if (pid == child->pid) {
	            match = child;
	        }
	    }
	
	    if (match == NULL) {
	        return FALSE;
	    }
	
	    rc = child_kill_helper(match);
	    if(rc == -ESRCH) {
	        /* It's gone, but hasn't shown up in waitpid() yet. Wait until we get
	         * SIGCHLD and let handler clean it up as normal (so we get the correct
	         * return code/status). The blocking alternative would be to call
	         * child_waitpid(match, 0).
	         */
	        pcmk__trace("Waiting for signal that child process %lld completed",
	                    (long long) match->pid);
	        return TRUE;
	
	    } else if(rc != 0) {
	        /* If KILL for some other reason set the WNOHANG flag since we
	         * can't be certain what happened.
	         */
	        waitflags = WNOHANG;
	    }
	
	    if (!child_waitpid(match, waitflags)) {
	        /* not much we can do if this occurs */
	        return FALSE;
	    }
	
	    child_list = g_list_remove(child_list, match);
	    child_free(match);
	    return TRUE;
	}
	
	/* Create/Log a new tracked process
	 * To track a process group, use -pid
	 *
	 * @TODO Using a non-positive pid (i.e. any child, or process group) would
	 *       likely not be useful since we will free the child after the first
	 *       completed process.
	 */
	void
	mainloop_child_add_with_flags(pid_t pid, int timeout, const char *desc,
	                              void *privatedata,
	                              enum mainloop_child_flags flags,
	                              pcmk__mainloop_child_exit_fn_t exit_fn)
	{
	    static bool need_init = TRUE;
	    mainloop_child_t *child = pcmk__assert_alloc(1, sizeof(mainloop_child_t));
	
	    child->pid = pid;
	    child->timerid = 0;
	    child->timeout = FALSE;
	    child->privatedata = privatedata;
	    child->exit_fn = exit_fn;
	    child->flags = flags;
	    child->desc = pcmk__str_copy(desc);
	
	    if (timeout) {
	        child->timerid = pcmk__create_timer(timeout, child_timeout_callback, child);
	    }
	
	    child_list = g_list_append(child_list, child);
	
	    if(need_init) {
	        need_init = FALSE;
	        /* SIGCHLD processing has to be invoked from mainloop.
	         * We do not want it to be possible to both add a child pid
	         * to mainloop, and have the pid's exit callback invoked within
	         * the same callstack. */
	        pcmk__create_timer(1, child_signal_init, NULL);
	    }
	}
	
	void
	mainloop_child_add(pid_t pid, int timeout, const char *desc, void *privatedata,
	                   pcmk__mainloop_child_exit_fn_t exit_fn)
	{
	    mainloop_child_add_with_flags(pid, timeout, desc, privatedata, 0, exit_fn);
	}
	
	static gboolean
	mainloop_timer_cb(void *user_data)
	{
	    int id = 0;
	    bool repeat = FALSE;
	    struct mainloop_timer_s *t = user_data;
	
	    pcmk__assert(t != NULL);
	
	    id = t->id;
	    t->id = 0; /* Ensure it's unset during callbacks so that
	                * mainloop_timer_running() works as expected
	                */
	
	    if(t->cb) {
	        pcmk__trace("Invoking callbacks for timer %s", t->name);
	        repeat = t->repeat;
	        if(t->cb(t->userdata) == FALSE) {
	            pcmk__trace("Timer %s complete", t->name);
	            repeat = FALSE;
	        }
	    }
	
	    if(repeat) {
	        /* Restore if repeating */
	        t->id = id;
	    }
	
	    return repeat;
	}
	
	bool
	mainloop_timer_running(mainloop_timer_t *t)
	{
	    if(t && t->id != 0) {
	        return TRUE;
	    }
	    return FALSE;
	}
	
	void
	mainloop_timer_start(mainloop_timer_t *t)
	{
	    mainloop_timer_stop(t);
	    if(t && t->period_ms > 0) {
	        pcmk__trace("Starting timer %s", t->name);
	        t->id = pcmk__create_timer(t->period_ms, mainloop_timer_cb, t);
	    }
	}
	
	void
	mainloop_timer_stop(mainloop_timer_t *t)
	{
	    if(t && t->id != 0) {
	        pcmk__trace("Stopping timer %s", t->name);
	        g_source_remove(t->id);
	        t->id = 0;
	    }
	}
	
	unsigned int
	mainloop_timer_set_period(mainloop_timer_t *t, unsigned int period_ms)
	{
	    unsigned int last = 0;
	
	    if(t) {
	        last = t->period_ms;
	        t->period_ms = period_ms;
	    }
	
	    if(t && t->id != 0 && last != t->period_ms) {
	        mainloop_timer_start(t);
	    }
	    return last;
	}
	
	mainloop_timer_t *
	mainloop_timer_add(const char *name, unsigned int period_ms, bool repeat,
	                   GSourceFunc cb, void *userdata)
	{
	    mainloop_timer_t *t = pcmk__assert_alloc(1, sizeof(mainloop_timer_t));
	
	    if (name != NULL) {
	        t->name = pcmk__assert_asprintf("%s-%u-%d", name, period_ms, repeat);
	    } else {
	        t->name = pcmk__assert_asprintf("%p-%u-%d", t, period_ms, repeat);
	    }
	    t->id = 0;
	    t->period_ms = period_ms;
	    t->repeat = repeat;
	    t->cb = cb;
	    t->userdata = userdata;
	    pcmk__trace("Created timer %s with %p %p", t->name, userdata, t->userdata);
	    return t;
	}
	
	void
	mainloop_timer_del(mainloop_timer_t *t)
	{
	    if(t) {
	        pcmk__trace("Destroying timer %s", t->name);
	        mainloop_timer_stop(t);
	        free(t->name);
	        free(t);
	    }
	}
	
	/*
	 * Helpers to make sure certain events aren't lost at shutdown
	 */
	
	static gboolean
	drain_timeout_cb(void *user_data)
	{
	    bool *timeout_popped = (bool*) user_data;
	
	    *timeout_popped = TRUE;
	    return FALSE;
	}
	
	/*!
	 * \brief Drain some remaining main loop events then quit it
	 *
	 * \param[in,out] mloop  Main loop to drain and quit
	 * \param[in]     n      Drain up to this many pending events
	 */
	void
	pcmk_quit_main_loop(GMainLoop *mloop, unsigned int n)
	{
	    if ((mloop != NULL) && g_main_loop_is_running(mloop)) {
	        GMainContext *ctx = g_main_loop_get_context(mloop);
	
	        /* Drain up to n events in case some memory clean-up is pending
	         * (helpful to reduce noise in valgrind output).
	         */
	        for (int i = 0; (i < n) && g_main_context_pending(ctx); ++i) {
	            g_main_context_dispatch(ctx);
	        }
	        g_main_loop_quit(mloop);
	    }
	}
	
	/*!
	 * \brief Process main loop events while a certain condition is met
	 *
	 * \param[in,out] mloop     Main loop to process
	 * \param[in]     timer_ms  Don't process longer than this amount of time
	 * \param[in]     check     Function that returns true if events should be
	 *                          processed
	 *
	 * \note This function is intended to be called at shutdown if certain important
	 *       events should not be missed. The caller would likely quit the main loop
	 *       or exit after calling this function. The check() function will be
	 *       passed the remaining timeout in milliseconds.
	 */
	void
	pcmk_drain_main_loop(GMainLoop *mloop, unsigned int timer_ms,
	                     bool (*check)(unsigned int))
	{
	    bool timeout_popped = FALSE;
	    unsigned int timer = 0;
	    GMainContext *ctx = NULL;
	
	    CRM_CHECK(mloop && check, return);
	
	    ctx = g_main_loop_get_context(mloop);
	    if (ctx) {
	        time_t start_time = time(NULL);
	
	        timer = pcmk__create_timer(timer_ms, drain_timeout_cb, &timeout_popped);
	        while (!timeout_popped
	               && check(timer_ms - (time(NULL) - start_time) * 1000)) {
	            g_main_context_iteration(ctx, TRUE);
	        }
	    }
	    if (!timeout_popped && (timer > 0)) {
	        g_source_remove(timer);
	    }
	}