services.c

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/*
 * Copyright 2010-2019 Andrew Beekhof <andrew@beekhof.net>
 *
 * 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>

#ifndef _GNU_SOURCE
#  define _GNU_SOURCE
#endif

#include <sys/types.h>
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <dirent.h>
#include <fcntl.h>

#include <crm/crm.h>
#include <crm/common/mainloop.h>
#include <crm/services.h>
#include <crm/stonith-ng.h>
#include <crm/msg_xml.h>
#include "services_private.h"
#include "services_lsb.h"

#if SUPPORT_UPSTART
#  include <upstart.h>
#endif

#if SUPPORT_SYSTEMD
#  include <systemd.h>
#endif

/* TODO: Develop a rollover strategy */

static int operations = 0;
static GHashTable *recurring_actions = NULL;

/* ops waiting to run async because of conflicting active
 * pending ops */
static GList *blocked_ops = NULL;

/* ops currently active (in-flight) */
static GList *inflight_ops = NULL;

static void handle_blocked_ops(void);

const char *
resources_find_service_class(const char *agent)
{
    if (services__lsb_agent_exists(agent)) {
        return PCMK_RESOURCE_CLASS_LSB;
    }

#if SUPPORT_SYSTEMD
    if (systemd_unit_exists(agent)) {
        return PCMK_RESOURCE_CLASS_SYSTEMD;
    }
#endif

#if SUPPORT_UPSTART
    if (upstart_job_exists(agent)) {
        return PCMK_RESOURCE_CLASS_UPSTART;
    }
#endif
    return NULL;
}

static inline void
init_recurring_actions(void)
{
    if (recurring_actions == NULL) {
        recurring_actions = g_hash_table_new_full(g_str_hash, g_str_equal, NULL,
                                                  NULL);
    }
}

static inline gboolean
inflight_systemd_or_upstart(svc_action_t *op)
{
    return (safe_str_eq(op->standard, PCMK_RESOURCE_CLASS_SYSTEMD)
            || safe_str_eq(op->standard, PCMK_RESOURCE_CLASS_UPSTART))
            && (g_list_find(inflight_ops, op) != NULL);
}

static char *
expand_resource_class(const char *rsc, const char *standard, const char *agent)
{
    char *expanded_class = NULL;

    if (strcasecmp(standard, PCMK_RESOURCE_CLASS_SERVICE) == 0) {
        const char *found_class = resources_find_service_class(agent);

        if (found_class) {
            crm_debug("Found %s agent %s for %s", found_class, agent, rsc);
            expanded_class = strdup(found_class);
        } else {
            crm_info("Assuming resource class lsb for agent %s for %s",
                     agent, rsc);
            expanded_class = strdup(PCMK_RESOURCE_CLASS_LSB);
        }
    } else {
        expanded_class = strdup(standard);
    }
    CRM_ASSERT(expanded_class);
    return expanded_class;
}

static char *
dup_file_path(const char *filename, const char *dirname)
{
    return (*filename == '/')? strdup(filename)
           : crm_strdup_printf("%s/%s", dirname, filename);
}

svc_action_t *
resources_action_create(const char *name, const char *standard,
                        const char *provider, const char *agent,
                        const char *action, guint interval_ms, int timeout,
                        GHashTable *params, enum svc_action_flags flags)
{
    svc_action_t *op = NULL;
    uint32_t ra_caps = 0;

    /*
     * Do some up front sanity checks before we go off and
     * build the svc_action_t instance.
     */

    if (crm_strlen_zero(name)) {
        crm_err("Cannot create operation without resource name");
        goto return_error;
    }

    if (crm_strlen_zero(standard)) {
        crm_err("Cannot create operation for %s without resource class", name);
        goto return_error;
    }
    ra_caps = pcmk_get_ra_caps(standard);

    if (is_set(ra_caps, pcmk_ra_cap_provider) && crm_strlen_zero(provider)) {
        crm_err("Cannot create operation for %s without provider", name);
        goto return_error;
    }

    if (crm_strlen_zero(agent)) {
        crm_err("Cannot create operation for %s without agent name", name);
        goto return_error;
    }

    if (crm_strlen_zero(action)) {
        crm_err("Cannot create operation for %s without operation name", name);
        goto return_error;
    }

    /*
     * Sanity checks passed, proceed!
     */

    op = calloc(1, sizeof(svc_action_t));
    op->opaque = calloc(1, sizeof(svc_action_private_t));
    op->rsc = strdup(name);
    op->interval_ms = interval_ms;
    op->timeout = timeout;
    op->standard = expand_resource_class(name, standard, agent);
    op->agent = strdup(agent);
    op->sequence = ++operations;
    op->flags = flags;
    op->id = generate_op_key(name, action, interval_ms);

    if (is_set(ra_caps, pcmk_ra_cap_status) && safe_str_eq(action, "monitor")) {
        op->action = strdup("status");
    } else {
        op->action = strdup(action);
    }

    if (is_set(ra_caps, pcmk_ra_cap_provider)) {
        op->provider = strdup(provider);
    }

    if (is_set(ra_caps, pcmk_ra_cap_params)) {
        op->params = params;
        params = NULL; // so we don't free them in this function
    }

    if (strcasecmp(op->standard, PCMK_RESOURCE_CLASS_OCF) == 0) {
        op->opaque->exec = crm_strdup_printf("%s/resource.d/%s/%s",
                                             OCF_ROOT_DIR, provider, agent);
        op->opaque->args[0] = strdup(op->opaque->exec);
        op->opaque->args[1] = strdup(op->action);

    } else if (strcasecmp(op->standard, PCMK_RESOURCE_CLASS_LSB) == 0) {
        op->opaque->exec = services__lsb_agent_path(op->agent);
        op->opaque->args[0] = strdup(op->opaque->exec);
        op->opaque->args[1] = strdup(op->action);

#if SUPPORT_SYSTEMD
    } else if (strcasecmp(op->standard, PCMK_RESOURCE_CLASS_SYSTEMD) == 0) {
        op->opaque->exec = strdup("systemd-dbus");
#endif
#if SUPPORT_UPSTART
    } else if (strcasecmp(op->standard, PCMK_RESOURCE_CLASS_UPSTART) == 0) {
        op->opaque->exec = strdup("upstart-dbus");
#endif
#if SUPPORT_NAGIOS
    } else if (strcasecmp(op->standard, PCMK_RESOURCE_CLASS_NAGIOS) == 0) {
        op->opaque->exec = dup_file_path(op->agent, NAGIOS_PLUGIN_DIR);
        op->opaque->args[0] = strdup(op->opaque->exec);

        if (safe_str_eq(op->action, "monitor") && (op->interval_ms == 0)) {
            /* Invoke --version for a nagios probe */
            op->opaque->args[1] = strdup("--version");

        } else if (op->params) {
            GHashTableIter iter;
            char *key = NULL;
            char *value = NULL;
            int index = 1;
            static int args_size = sizeof(op->opaque->args) / sizeof(char *);

            g_hash_table_iter_init(&iter, op->params);

            while (g_hash_table_iter_next(&iter, (gpointer *) & key, (gpointer *) & value) &&
                   index <= args_size - 3) {

                if (safe_str_eq(key, XML_ATTR_CRM_VERSION) || strstr(key, CRM_META "_")) {
                    continue;
                }
                op->opaque->args[index++] = crm_strdup_printf("--%s", key);
                op->opaque->args[index++] = strdup(value);
            }
        }

        // Nagios actions don't need to keep the parameters
        if (op->params != NULL) {
            g_hash_table_destroy(op->params);
            op->params = NULL;
        }
#endif
    } else {
        crm_err("Unknown resource standard: %s", op->standard);
        goto return_error;
    }

    if(params) {
        g_hash_table_destroy(params);
    }
    return op;

  return_error:
    if(params) {
        g_hash_table_destroy(params);
    }
    services_action_free(op);

    return NULL;
}

svc_action_t *
services_action_create_generic(const char *exec, const char *args[])
{
    svc_action_t *op;
    unsigned int cur_arg;

    op = calloc(1, sizeof(*op));
    op->opaque = calloc(1, sizeof(svc_action_private_t));

    op->opaque->exec = strdup(exec);
    op->opaque->args[0] = strdup(exec);

    for (cur_arg = 1; args && args[cur_arg - 1]; cur_arg++) {
        op->opaque->args[cur_arg] = strdup(args[cur_arg - 1]);

        if (cur_arg == DIMOF(op->opaque->args) - 1) {
            crm_err("svc_action_t args list not long enough for '%s' execution request.", exec);
            break;
        }
    }

    return op;
}

svc_action_t *
services_alert_create(const char *id, const char *exec, int timeout,
                      GHashTable *params, int sequence, void *cb_data)
{
    svc_action_t *action = services_action_create_generic(exec, NULL);

    CRM_ASSERT(action);
    action->timeout = timeout;
    action->id = strdup(id);
    action->params = params;
    action->sequence = sequence;
    action->cb_data = cb_data;
    return action;
}

int
services_action_user(svc_action_t *op, const char *user)
{
    CRM_CHECK((op != NULL) && (user != NULL), return -EINVAL);
    return crm_user_lookup(user, &(op->opaque->uid), &(op->opaque->gid));
}

gboolean
services_alert_async(svc_action_t *action, void (*cb)(svc_action_t *op))
{
    action->synchronous = false;
    action->opaque->callback = cb;
    return services_os_action_execute(action);
}

#if SUPPORT_DBUS

void
services_set_op_pending(svc_action_t *op, DBusPendingCall *pending)
{
    if (op->opaque->pending && (op->opaque->pending != pending)) {
        if (pending) {
            crm_info("Lost pending %s DBus call (%p)", op->id, op->opaque->pending);
        } else {
            crm_trace("Done with pending %s DBus call (%p)", op->id, op->opaque->pending);
        }
        dbus_pending_call_unref(op->opaque->pending);
    }
    op->opaque->pending = pending;
    if (pending) {
        crm_trace("Updated pending %s DBus call (%p)", op->id, pending);
    } else {
        crm_trace("Cleared pending %s DBus call", op->id);
    }
}
#endif

void
services_action_cleanup(svc_action_t * op)
{
    if ((op == NULL) || (op->opaque == NULL)) {
        return;
    }

#if SUPPORT_DBUS
    if(op->opaque->timerid != 0) {
        crm_trace("Removing timer for call %s to %s", op->action, op->rsc);
        g_source_remove(op->opaque->timerid);
        op->opaque->timerid = 0;
    }

    if(op->opaque->pending) {
        if (dbus_pending_call_get_completed(op->opaque->pending)) {
            // This should never be the case
            crm_warn("Result of %s op %s was unhandled",
                     op->standard, op->id);
        } else {
            crm_debug("Will ignore any result of canceled %s op %s",
                      op->standard, op->id);
        }
        dbus_pending_call_cancel(op->opaque->pending);
        services_set_op_pending(op, NULL);
    }
#endif

    if (op->opaque->stderr_gsource) {
        mainloop_del_fd(op->opaque->stderr_gsource);
        op->opaque->stderr_gsource = NULL;
    }

    if (op->opaque->stdout_gsource) {
        mainloop_del_fd(op->opaque->stdout_gsource);
        op->opaque->stdout_gsource = NULL;
    }
}

void
services_action_free(svc_action_t * op)
{
    unsigned int i;

    if (op == NULL) {
        return;
    }

    /* The operation should be removed from all tracking lists by this point.
     * If it's not, we have a bug somewhere, so bail. That may lead to a
     * memory leak, but it's better than a use-after-free segmentation fault.
     */
    CRM_CHECK(g_list_find(inflight_ops, op) == NULL, return);
    CRM_CHECK(g_list_find(blocked_ops, op) == NULL, return);
    CRM_CHECK((recurring_actions == NULL)
              || (g_hash_table_lookup(recurring_actions, op->id) == NULL),
              return);

    services_action_cleanup(op);

    if (op->opaque->repeat_timer) {
        g_source_remove(op->opaque->repeat_timer);
        op->opaque->repeat_timer = 0;
    }

    free(op->id);
    free(op->opaque->exec);

    for (i = 0; i < DIMOF(op->opaque->args); i++) {
        free(op->opaque->args[i]);
    }

    free(op->opaque);
    free(op->rsc);
    free(op->action);

    free(op->standard);
    free(op->agent);
    free(op->provider);

    free(op->stdout_data);
    free(op->stderr_data);

    if (op->params) {
        g_hash_table_destroy(op->params);
        op->params = NULL;
    }

    free(op);
}

gboolean
cancel_recurring_action(svc_action_t * op)
{
    crm_info("Cancelling %s operation %s", op->standard, op->id);

    if (recurring_actions) {
        g_hash_table_remove(recurring_actions, op->id);
    }

    if (op->opaque->repeat_timer) {
        g_source_remove(op->opaque->repeat_timer);
        op->opaque->repeat_timer = 0;
    }

    return TRUE;
}

gboolean
services_action_cancel(const char *name, const char *action, guint interval_ms)
{
    gboolean cancelled = FALSE;
    char *id = generate_op_key(name, action, interval_ms);
    svc_action_t *op = NULL;

    /* We can only cancel a recurring action */
    init_recurring_actions();
    op = g_hash_table_lookup(recurring_actions, id);
    if (op == NULL) {
        goto done;
    }

    /* Tell operation_finalize() not to reschedule the operation */
    op->cancel = TRUE;

    /* Stop tracking it as a recurring operation, and stop its repeat timer */
    cancel_recurring_action(op);

    /* If the op has a PID, it's an in-flight child process, so kill it.
     *
     * Whether the kill succeeds or fails, the main loop will send the op to
     * operation_finished() (and thus operation_finalize()) when the process
     * goes away.
     */
    if (op->pid != 0) {
        crm_info("Terminating in-flight op %s (pid %d) early because it was cancelled",
                 id, op->pid);
        cancelled = mainloop_child_kill(op->pid);
        if (cancelled == FALSE) {
            crm_err("Termination of %s (pid %d) failed", id, op->pid);
        }
        goto done;
    }

#if SUPPORT_DBUS
    // In-flight systemd and upstart ops don't have a pid
    if (inflight_systemd_or_upstart(op)) {
        inflight_ops = g_list_remove(inflight_ops, op);

        /* This will cause any result that comes in later to be discarded, so we
         * don't call the callback and free the operation twice.
         */
        services_action_cleanup(op);
    }
#endif

    // The rest of this is essentially equivalent to operation_finalize(),
    // except without calling handle_blocked_ops()

    // Report operation as cancelled
    op->status = PCMK_LRM_OP_CANCELLED;
    if (op->opaque->callback) {
        op->opaque->callback(op);
    }

    blocked_ops = g_list_remove(blocked_ops, op);
    services_action_free(op);
    cancelled = TRUE;
    // @TODO Initiate handle_blocked_ops() asynchronously

done:
    free(id);
    return cancelled;
}

gboolean
services_action_kick(const char *name, const char *action, guint interval_ms)
{
    svc_action_t * op = NULL;
    char *id = generate_op_key(name, action, interval_ms);

    init_recurring_actions();
    op = g_hash_table_lookup(recurring_actions, id);
    free(id);

    if (op == NULL) {
        return FALSE;
    }


    if (op->pid || inflight_systemd_or_upstart(op)) {
        return TRUE;
    } else {
        if (op->opaque->repeat_timer) {
            g_source_remove(op->opaque->repeat_timer);
            op->opaque->repeat_timer = 0;
        }
        recurring_action_timer(op);
        return TRUE;
    }

}

static gboolean
handle_duplicate_recurring(svc_action_t * op)
{
    svc_action_t * dup = NULL;

    /* check for duplicates */
    dup = g_hash_table_lookup(recurring_actions, op->id);

    if (dup && (dup != op)) {
        /* update user data */
        if (op->opaque->callback) {
            dup->opaque->callback = op->opaque->callback;
            dup->cb_data = op->cb_data;
            op->cb_data = NULL;
        }
        /* immediately execute the next interval */
        if (dup->pid != 0) {
            if (op->opaque->repeat_timer) {
                g_source_remove(op->opaque->repeat_timer);
                op->opaque->repeat_timer = 0;
            }
            recurring_action_timer(dup);
        }
        /* free the duplicate */
        services_action_free(op);
        return TRUE;
    }

    return FALSE;
}

inline static gboolean
action_exec_helper(svc_action_t * op)
{
    /* Whether a/synchronous must be decided (op->synchronous) beforehand. */
    if (op->standard
        && (strcasecmp(op->standard, PCMK_RESOURCE_CLASS_UPSTART) == 0)) {
#if SUPPORT_UPSTART
        return upstart_job_exec(op);
#endif
    } else if (op->standard && strcasecmp(op->standard,
                                          PCMK_RESOURCE_CLASS_SYSTEMD) == 0) {
#if SUPPORT_SYSTEMD
        return systemd_unit_exec(op);
#endif
    } else {
        return services_os_action_execute(op);
    }
    /* The 'op' has probably been freed if the execution functions return TRUE
       for the asynchronous 'op'. */
    /* Avoid using the 'op' in here. */

    return FALSE;
}

void
services_add_inflight_op(svc_action_t * op)
{
    if (op == NULL) {
        return;
    }

    CRM_ASSERT(op->synchronous == FALSE);

    /* keep track of ops that are in-flight to avoid collisions in the same namespace */
    if (op->rsc) {
        inflight_ops = g_list_append(inflight_ops, op);
    }
}

void
services_untrack_op(svc_action_t *op)
{
    /* Op is no longer in-flight or blocked */
    inflight_ops = g_list_remove(inflight_ops, op);
    blocked_ops = g_list_remove(blocked_ops, op);

    /* Op is no longer blocking other ops, so check if any need to run */
    handle_blocked_ops();
}

gboolean
services_action_async_fork_notify(svc_action_t * op,
                                  void (*action_callback) (svc_action_t *),
                                  void (*action_fork_callback) (svc_action_t *))
{
    op->synchronous = false;
    if (action_callback) {
        op->opaque->callback = action_callback;
    }
    if (action_fork_callback) {
        op->opaque->fork_callback = action_fork_callback;
    }

    if (op->interval_ms > 0) {
        init_recurring_actions();
        if (handle_duplicate_recurring(op) == TRUE) {
            /* entry rescheduled, dup freed */
            /* exit early */
            return TRUE;
        }
        g_hash_table_replace(recurring_actions, op->id, op);
    }

    if (op->rsc && is_op_blocked(op->rsc)) {
        blocked_ops = g_list_append(blocked_ops, op);
        return TRUE;
    }

    return action_exec_helper(op);
}

gboolean
services_action_async(svc_action_t * op,
                      void (*action_callback) (svc_action_t *))
{
    return services_action_async_fork_notify(op, action_callback, NULL);
}

static gboolean processing_blocked_ops = FALSE;

gboolean
is_op_blocked(const char *rsc)
{
    GList *gIter = NULL;
    svc_action_t *op = NULL;

    for (gIter = inflight_ops; gIter != NULL; gIter = gIter->next) {
        op = gIter->data;
        if (safe_str_eq(op->rsc, rsc)) {
            return TRUE;
        }
    }

    return FALSE;
}

static void
handle_blocked_ops(void)
{
    GList *executed_ops = NULL;
    GList *gIter = NULL;
    svc_action_t *op = NULL;
    gboolean res = FALSE;

    if (processing_blocked_ops) {
        /* avoid nested calling of this function */
        return;
    }

    processing_blocked_ops = TRUE;

    /* n^2 operation here, but blocked ops are incredibly rare. this list
     * will be empty 99% of the time. */
    for (gIter = blocked_ops; gIter != NULL; gIter = gIter->next) {
        op = gIter->data;
        if (is_op_blocked(op->rsc)) {
            continue;
        }
        executed_ops = g_list_append(executed_ops, op);
        res = action_exec_helper(op);
        if (res == FALSE) {
            op->status = PCMK_LRM_OP_ERROR;
            /* this can cause this function to be called recursively
             * which is why we have processing_blocked_ops static variable */
            operation_finalize(op);
        }
    }

    for (gIter = executed_ops; gIter != NULL; gIter = gIter->next) {
        op = gIter->data;
        blocked_ops = g_list_remove(blocked_ops, op);
    }
    g_list_free(executed_ops);

    processing_blocked_ops = FALSE;
}

#if SUPPORT_NAGIOS
static int
nagios_get_metadata(const char *type, char **output)
{
    int rc = pcmk_ok;
    FILE *file_strm = NULL;
    int start = 0, length = 0, read_len = 0;
    char *metadata_file = crm_strdup_printf("%s/%s.xml",
                                            NAGIOS_METADATA_DIR, type);

    file_strm = fopen(metadata_file, "r");
    if (file_strm == NULL) {
        crm_err("Metadata file %s does not exist", metadata_file);
        free(metadata_file);
        return -EIO;
    }

    /* see how big the file is */
    start = ftell(file_strm);
    fseek(file_strm, 0L, SEEK_END);
    length = ftell(file_strm);
    fseek(file_strm, 0L, start);

    CRM_ASSERT(length >= 0);
    CRM_ASSERT(start == ftell(file_strm));

    if (length <= 0) {
        crm_info("%s was not valid", metadata_file);
        free(*output);
        *output = NULL;
        rc = -EIO;

    } else {
        crm_trace("Reading %d bytes from file", length);
        *output = calloc(1, (length + 1));
        read_len = fread(*output, 1, length, file_strm);
        if (read_len != length) {
            crm_err("Calculated and read bytes differ: %d vs. %d",
                    length, read_len);
            free(*output);
            *output = NULL;
            rc = -EIO;
        }
    }

    fclose(file_strm);
    free(metadata_file);
    return rc;
}
#endif

static gboolean
action_get_metadata(svc_action_t *op)
{
    const char *class = op->standard;

    if (op->agent == NULL) {
        crm_err("meta-data requested without specifying agent");
        return FALSE;
    }

    if (class == NULL) {
        crm_err("meta-data requested for agent %s without specifying class",
                op->agent);
        return FALSE;
    }

    if (!strcmp(class, PCMK_RESOURCE_CLASS_SERVICE)) {
        class = resources_find_service_class(op->agent);
    }

    if (class == NULL) {
        crm_err("meta-data requested for %s, but could not determine class",
                op->agent);
        return FALSE;
    }

    if (safe_str_eq(class, PCMK_RESOURCE_CLASS_LSB)) {
        return (services__get_lsb_metadata(op->agent, &op->stdout_data) >= 0);
    }

#if SUPPORT_NAGIOS
    if (safe_str_eq(class, PCMK_RESOURCE_CLASS_NAGIOS)) {
        return (nagios_get_metadata(op->agent, &op->stdout_data) >= 0);
    }
#endif

    return action_exec_helper(op);
}

gboolean
services_action_sync(svc_action_t * op)
{
    gboolean rc = TRUE;

    if (op == NULL) {
        crm_trace("No operation to execute");
        return FALSE;
    }

    op->synchronous = true;

    if (safe_str_eq(op->action, "meta-data")) {
        /* Synchronous meta-data operations are handled specially. Since most
         * resource classes don't provide any meta-data, it has to be
         * synthesized from available information about the agent.
         *
         * services_action_async() doesn't treat meta-data actions specially, so
         * it will result in an error for classes that don't support the action.
         */
        rc = action_get_metadata(op);
    } else {
        rc = action_exec_helper(op);
    }
    crm_trace(" > " CRM_OP_FMT ": %s = %d",
              op->rsc, op->action, op->interval_ms, op->opaque->exec, op->rc);
    if (op->stdout_data) {
        crm_trace(" >  stdout: %s", op->stdout_data);
    }
    if (op->stderr_data) {
        crm_trace(" >  stderr: %s", op->stderr_data);
    }
    return rc;
}

GList *
get_directory_list(const char *root, gboolean files, gboolean executable)
{
    return services_os_get_directory_list(root, files, executable);
}

GList *
resources_list_standards(void)
{
    GList *standards = NULL;
    GList *agents = NULL;

    standards = g_list_append(standards, strdup(PCMK_RESOURCE_CLASS_OCF));
    standards = g_list_append(standards, strdup(PCMK_RESOURCE_CLASS_LSB));
    standards = g_list_append(standards, strdup(PCMK_RESOURCE_CLASS_SERVICE));

#if SUPPORT_SYSTEMD
    agents = systemd_unit_listall();
    if (agents) {
        standards = g_list_append(standards,
                                  strdup(PCMK_RESOURCE_CLASS_SYSTEMD));
        g_list_free_full(agents, free);
    }
#endif

#if SUPPORT_UPSTART
    agents = upstart_job_listall();
    if (agents) {
        standards = g_list_append(standards,
                                  strdup(PCMK_RESOURCE_CLASS_UPSTART));
        g_list_free_full(agents, free);
    }
#endif

#if SUPPORT_NAGIOS
    agents = resources_os_list_nagios_agents();
    if (agents) {
        standards = g_list_append(standards,
                                  strdup(PCMK_RESOURCE_CLASS_NAGIOS));
        g_list_free_full(agents, free);
    }
#endif

    return standards;
}

GList *
resources_list_providers(const char *standard)
{
    if (is_set(pcmk_get_ra_caps(standard), pcmk_ra_cap_provider)) {
        return resources_os_list_ocf_providers();
    }

    return NULL;
}

GList *
resources_list_agents(const char *standard, const char *provider)
{
    if ((standard == NULL)
        || (strcasecmp(standard, PCMK_RESOURCE_CLASS_SERVICE) == 0)) {

        GList *tmp1;
        GList *tmp2;
        GList *result = services__list_lsb_agents();

        if (standard == NULL) {
            tmp1 = result;
            tmp2 = resources_os_list_ocf_agents(NULL);
            if (tmp2) {
                result = g_list_concat(tmp1, tmp2);
            }
        }
#if SUPPORT_SYSTEMD
        tmp1 = result;
        tmp2 = systemd_unit_listall();
        if (tmp2) {
            result = g_list_concat(tmp1, tmp2);
        }
#endif

#if SUPPORT_UPSTART
        tmp1 = result;
        tmp2 = upstart_job_listall();
        if (tmp2) {
            result = g_list_concat(tmp1, tmp2);
        }
#endif

        return result;

    } else if (strcasecmp(standard, PCMK_RESOURCE_CLASS_OCF) == 0) {
        return resources_os_list_ocf_agents(provider);
    } else if (strcasecmp(standard, PCMK_RESOURCE_CLASS_LSB) == 0) {
        return services__list_lsb_agents();
#if SUPPORT_SYSTEMD
    } else if (strcasecmp(standard, PCMK_RESOURCE_CLASS_SYSTEMD) == 0) {
        return systemd_unit_listall();
#endif
#if SUPPORT_UPSTART
    } else if (strcasecmp(standard, PCMK_RESOURCE_CLASS_UPSTART) == 0) {
        return upstart_job_listall();
#endif
#if SUPPORT_NAGIOS
    } else if (strcasecmp(standard, PCMK_RESOURCE_CLASS_NAGIOS) == 0) {
        return resources_os_list_nagios_agents();
#endif
    }

    return NULL;
}

gboolean
resources_agent_exists(const char *standard, const char *provider, const char *agent)
{
    GList *standards = NULL;
    GList *providers = NULL;
    GListPtr iter = NULL;
    gboolean rc = FALSE;
    gboolean has_providers = FALSE;

    standards = resources_list_standards();
    for (iter = standards; iter != NULL; iter = iter->next) {
        if (crm_str_eq(iter->data, standard, TRUE)) {
            rc = TRUE;
            break;
        }
    }

    if (rc == FALSE) {
        goto done;
    }

    rc = FALSE;

    has_providers = is_set(pcmk_get_ra_caps(standard), pcmk_ra_cap_provider);
    if (has_providers == TRUE && provider != NULL) {
        providers = resources_list_providers(standard);
        for (iter = providers; iter != NULL; iter = iter->next) {
            if (crm_str_eq(iter->data, provider, TRUE)) {
                rc = TRUE;
                break;
            }
        }
    } else if (has_providers == FALSE && provider == NULL) {
        rc = TRUE;
    }

    if (rc == FALSE) {
        goto done;
    }

    if (safe_str_eq(standard, PCMK_RESOURCE_CLASS_SERVICE)) {
        if (services__lsb_agent_exists(agent)) {
            rc = TRUE;
#if SUPPORT_SYSTEMD
        } else if (systemd_unit_exists(agent)) {
            rc = TRUE;
#endif

#if SUPPORT_UPSTART
        } else if (upstart_job_exists(agent)) {
            rc = TRUE;
#endif
        } else {
            rc = FALSE;
        }

    } else if (safe_str_eq(standard, PCMK_RESOURCE_CLASS_OCF)) {
        rc = services__ocf_agent_exists(provider, agent);

    } else if (safe_str_eq(standard, PCMK_RESOURCE_CLASS_LSB)) {
        rc = services__lsb_agent_exists(agent);

#if SUPPORT_SYSTEMD
    } else if (safe_str_eq(standard, PCMK_RESOURCE_CLASS_SYSTEMD)) {
        rc = systemd_unit_exists(agent);
#endif

#if SUPPORT_UPSTART
    } else if (safe_str_eq(standard, PCMK_RESOURCE_CLASS_UPSTART)) {
        rc = upstart_job_exists(agent);
#endif

#if SUPPORT_NAGIOS
    } else if (safe_str_eq(standard, PCMK_RESOURCE_CLASS_NAGIOS)) {
        rc = services__nagios_agent_exists(agent);
#endif

    } else {
        rc = FALSE;
    }

done:
    g_list_free(standards);
    g_list_free(providers);
    return rc;
}