trigger.c

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/*
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */
 
/*
 * $Id: 46578ae6aea94392125e6ac15c86eb4ae151197a $
 *
 * @file trigger.c
 * @brief Execute scripts when a server event occurs.
 *
 * @copyright 2015 The FreeRADIUS server project
 */
RCSID("$Id: 46578ae6aea94392125e6ac15c86eb4ae151197a $")
 
#include <freeradius-devel/protocol/freeradius/freeradius.internal.h>
#include <freeradius-devel/server/cf_file.h>
#include <freeradius-devel/server/cf_parse.h>
#include <freeradius-devel/server/cf_util.h>
#include <freeradius-devel/server/exec.h>
#include <freeradius-devel/server/main_loop.h>
#include <freeradius-devel/server/request_data.h>
#include <freeradius-devel/server/trigger.h>
#include <freeradius-devel/unlang/function.h>
#include <freeradius-devel/unlang/interpret.h>
#include <freeradius-devel/unlang/subrequest.h>
#include <freeradius-devel/unlang/xlat.h>
 
#include <freeradius-devel/util/atexit.h>
#include <freeradius-devel/util/debug.h>
 
#include <sys/wait.h>
 
/** Whether triggers are enabled globally
 *
 */
static bool                     triggers_init;
static CONF_SECTION const       *trigger_exec_main, *trigger_exec_subcs;
static fr_rb_tree_t             *trigger_last_fired_tree;
static pthread_mutex_t          *trigger_mutex;
 
#define REQUEST_INDEX_TRIGGER_NAME      1
#define REQUEST_INDEX_TRIGGER_ARGS      2
 
/** Describes a rate limiting entry for a trigger
 *
 */
typedef struct {
        fr_rb_node_t    node;           //!< Entry in the trigger last fired tree.
        CONF_ITEM       *ci;            //!< Config item this rate limit counter is associated with.
        fr_time_t       last_fired;     //!< When this trigger last fired.
} trigger_last_fired_t;
 
xlat_arg_parser_t const trigger_xlat_args[] = {
        { .required = true, .single = true, .type = FR_TYPE_STRING },
        XLAT_ARG_PARSER_TERMINATOR
};
 
/** Retrieve attributes from a special trigger list
 *
 */
xlat_action_t trigger_xlat(TALLOC_CTX *ctx, fr_dcursor_t *out,
                           UNUSED xlat_ctx_t const *xctx,
                           request_t *request, fr_value_box_list_t *in)
{
        fr_pair_list_t          *head = NULL;
        fr_dict_attr_t const    *da;
        fr_pair_t               *vp;
        fr_value_box_t          *in_head = fr_value_box_list_head(in);
        fr_value_box_t          *vb;
 
        if (!triggers_init) {
                ERROR("Triggers are not enabled");
                return XLAT_ACTION_FAIL;
        }
 
        if (!request_data_reference(request, &trigger_exec_main, REQUEST_INDEX_TRIGGER_NAME)) {
                ERROR("trigger xlat may only be used in a trigger command");
                return XLAT_ACTION_FAIL;
        }
 
        head = request_data_reference(request, &trigger_exec_main, REQUEST_INDEX_TRIGGER_ARGS);
 
        da = fr_dict_attr_by_name(NULL, fr_dict_root(request->dict ? request->dict : fr_dict_internal()),
                                  in_head->vb_strvalue);
        if (!da) {
                ERROR("Unknown attribute \"%pV\"", in_head);
                return XLAT_ACTION_FAIL;
        }
 
        vp = fr_pair_find_by_da(head, NULL, da);
        if (!vp) {
                ERROR("Attribute \"%pV\" is not valid for this trigger", in_head);
                return XLAT_ACTION_FAIL;
        }
 
        MEM(vb = fr_value_box_alloc_null(ctx));
        fr_value_box_copy(vb, vb, &vp->data);
        fr_dcursor_append(out, vb);
        return XLAT_ACTION_DONE;
}
 
static void _trigger_last_fired_free(void *data)
{
        talloc_free(data);
}
 
/** Compares two last fired structures
 *
 * @param one first pointer to compare.
 * @param two second pointer to compare.
 * @return CMP(one, two)
 */
static int8_t _trigger_last_fired_cmp(void const *one, void const *two)
{
        trigger_last_fired_t const *a = one, *b = two;
 
        return CMP(a->ci, b->ci);
}
 
/** Return whether triggers are enabled
 *
 */
bool trigger_enabled(void)
{
        return triggers_init;
}
 
typedef struct {
        char                    *command;       //!< Name of the trigger.
        xlat_exp_head_t         *xlat;          //!< xlat representation of the trigger args.
        fr_value_box_list_t     args;           //!< Arguments to pass to the trigger exec.
 
        fr_exec_state_t         exec;           //!< Used for asynchronous execution.
        fr_time_delta_t         timeout;        //!< How long the trigger has to run.
} fr_trigger_t;
 
static unlang_action_t trigger_done(rlm_rcode_t *p_result, UNUSED int *priority,
                                    request_t *request, void *rctx)
{
        fr_trigger_t    *trigger = talloc_get_type_abort(rctx, fr_trigger_t);
 
        if (trigger->exec.status == 0) {
                RDEBUG2("Trigger \"%s\" done", trigger->command);
                RETURN_MODULE_OK;
        }
 
        RERROR("Trigger \"%s\" failed", trigger->command);
 
        RETURN_MODULE_FAIL;
}
 
static unlang_action_t trigger_resume(rlm_rcode_t *p_result, UNUSED int *priority,
                                      request_t *request, void *rctx)
{
        fr_trigger_t    *trigger = talloc_get_type_abort(rctx, fr_trigger_t);
 
        if (fr_value_box_list_empty(&trigger->args)) {
                RERROR("Failed trigger \"%s\" - did not expand to anything", trigger->command);
                RETURN_MODULE_FAIL;
        }
 
        /*
         *      fr_exec_oneshot just calls request_resume when it's
         *      done.
         */
        if (fr_exec_oneshot(request, &trigger->exec, request,
                          &trigger->args,
                          NULL, false, true,
                          false,
                          false, NULL, trigger->timeout) < 0) {
        fail:
                RPERROR("Failed running trigger \"%s\"", trigger->command);
                RETURN_MODULE_FAIL;
        }
 
        /*
         *      Swap out the repeat function so that when we're
         *      resumed the code path in the interpreter pops
         *      the frame.  If we don't do this trigger_run just
         *      gets called repeatedly.
         */
        if (unlang_function_repeat_set(request, trigger_done) < 0) {
                fr_exec_oneshot_cleanup(&trigger->exec, SIGKILL);
                goto fail;
        }
 
        return UNLANG_ACTION_YIELD;
}
 
static unlang_action_t trigger_run(rlm_rcode_t *p_result, UNUSED int *priority, request_t *request, void *uctx)
{
        fr_trigger_t    *trigger = talloc_get_type_abort(uctx, fr_trigger_t);
 
        RDEBUG("Running trigger \"%s\"", trigger->command);
 
        if (unlang_xlat_push(request, NULL, &trigger->args, request,
                             trigger->xlat, UNLANG_SUB_FRAME) < 0) RETURN_MODULE_FAIL;
 
        return UNLANG_ACTION_PUSHED_CHILD;
}
 
 
/** Execute a trigger - call an executable to process an event
 *
 * @note Calls to this function will be ignored if #trigger_exec_init has not been called.
 *
 * @param[in] intp              Interpreter to run the trigger with.  If this is NULL the
 *                              trigger will be executed synchronously.
 * @param[in] cs                to search for triggers in.
 *                              If cs is not NULL, the portion after the last '.' in name is used for the trigger.
 *                              If cs is NULL, the entire name is used to find the trigger in the global trigger
 *                              section.
 * @param[in] name              the path relative to the global trigger section ending in the trigger name
 *                              e.g. module.ldap.pool.start.
 * @param[in] rate_limit        whether to rate limit triggers.
 * @param[in] args              to make available via the @verbatim %trigger(<arg>) @endverbatim xlat.
 * @return
 *      - 0 on success.
 *      - -1 on failure.
 */
int trigger_exec(unlang_interpret_t *intp,
                 CONF_SECTION const *cs, char const *name, bool rate_limit, fr_pair_list_t *args)
{
        CONF_SECTION const      *subcs;
 
        CONF_ITEM               *ci;
        CONF_PAIR               *cp;
 
        char const              *attr;
        char const              *value;
 
        request_t               *request;
        fr_trigger_t            *trigger;
        ssize_t                 slen;
 
        /*
         *      noop if trigger_exec_init was never called
         */
        if (!triggers_init) return 0;
 
        /*
         *      Use global "trigger" section if no local config is given.
         */
        if (!cs) {
                cs = trigger_exec_main;
                attr = name;
        } else {
                /*
                 *      Try to use pair name, rather than reference.
                 */
                attr = strrchr(name, '.');
                if (attr) {
                        attr++;
                } else {
                        attr = name;
                }
        }
 
        /*
         *      Find local "trigger" subsection.  If it isn't found,
         *      try using the global "trigger" section, and reset the
         *      reference to the full path, rather than the sub-path.
         */
        subcs = cf_section_find(cs, "trigger", NULL);
        if (!subcs && trigger_exec_main && (cs != trigger_exec_main)) {
                subcs = trigger_exec_subcs;
                attr = name;
        }
        if (!subcs) return -1;
 
        ci = cf_reference_item(subcs, trigger_exec_main, attr);
        if (!ci) {
                DEBUG3("No trigger configured for: %s", attr);
                return -1;
        }
 
        if (!cf_item_is_pair(ci)) {
                ERROR("Trigger is not a configuration variable: %s", attr);
                return -1;
        }
 
        cp = cf_item_to_pair(ci);
        if (!cp) return -1;
 
        value = cf_pair_value(cp);
        if (!value) {
                ERROR("Trigger has no value: %s", name);
                return -1;
        }
 
        /*
         *      Don't do any real work if we're checking the
         *      configuration.  i.e. don't run "start" or "stop"
         *      triggers on "radiusd -XC".
         */
        if (check_config) return 0;
 
        /*
         *      Perform periodic rate_limiting.
         */
        if (rate_limit) {
                trigger_last_fired_t    find, *found;
                fr_time_t               now = fr_time();
 
                find.ci = ci;
 
                pthread_mutex_lock(trigger_mutex);
 
                found = fr_rb_find(trigger_last_fired_tree, &find);
                if (!found) {
                        MEM(found = talloc(NULL, trigger_last_fired_t));
                        found->ci = ci;
                        /*
                         *      Initialise last_fired to 2 seconds ago so
                         *      the trigger fires on the first occurrence
                         */
                        found->last_fired = fr_time_wrap(NSEC * -2);
 
                        fr_rb_insert(trigger_last_fired_tree, found);
                }
 
                pthread_mutex_unlock(trigger_mutex);
 
                /*
                 *      Send the rate_limited traps at most once per second.
                 */
                if (fr_time_to_sec(found->last_fired) == fr_time_to_sec(now)) return -1;
                found->last_fired = now;
        }
 
        /*
         *      Allocate a request to run asynchronously in the interpreter.
         */
        request = request_alloc_internal(NULL, (&(request_init_args_t){ .detachable = true }));
 
        /*
         *      Add the args to the request data, so they can be picked up by the
         *      trigger_xlat function.
         */
        if (args) {
                fr_pair_list_t *local_args;
 
                MEM(local_args = talloc_zero(request, fr_pair_list_t));
                fr_pair_list_init(local_args);
                if (fr_pair_list_copy(local_args, local_args, args) < 0) {
                        PERROR("Failed copying trigger arguments");
                args_error:
                        talloc_free(request);
                        return -1;
                }
 
                if (request_data_add(request, &trigger_exec_main, REQUEST_INDEX_TRIGGER_ARGS, local_args,
                                      false, false, false) < 0) goto args_error;
        }
 
        {
                void *name_tmp;
 
                memcpy(&name_tmp, &name, sizeof(name_tmp));
 
                if (request_data_add(request, &trigger_exec_main, REQUEST_INDEX_TRIGGER_NAME,
                                     name_tmp, false, false, false) < 0) {
                        talloc_free(request);
                        return -1;
                }
        }
 
        MEM(trigger = talloc_zero(request, fr_trigger_t));
        fr_value_box_list_init(&trigger->args);
        trigger->command = talloc_strdup(trigger, value);
        trigger->timeout = fr_time_delta_from_sec(5);   /* FIXME - Should be configurable? */
 
        slen = xlat_tokenize_argv(trigger, &trigger->xlat,
                                  &FR_SBUFF_IN(trigger->command, talloc_array_length(trigger->command) - 1),
                                  NULL, NULL, NULL, false, false);
        if (slen <= 0) {
                char *spaces, *text;
 
                fr_canonicalize_error(trigger, &spaces, &text, slen, trigger->command);
 
                cf_log_err(cp, "Failed parsing trigger command");
                cf_log_err(cp, "%s", text);
                cf_log_perr(cp, "%s^", spaces);
 
                talloc_free(request);
                talloc_free(spaces);
                talloc_free(text);
                return -1;
        }
 
        /*
         *      If we're not running it locally use the default
         *      interpreter for the thread.
         */
        if (intp) {
                unlang_interpret_set(request, intp);
                if (unlang_subrequest_child_push_and_detach(request) < 0) {
                error:
                        PERROR("Running trigger failed");
                        talloc_free(request);
                        return -1;
                }
        }
 
        if (xlat_finalize(trigger->xlat, intp ? unlang_interpret_event_list(request) : main_loop_event_list()) < 0) {
                fr_strerror_const("Failed performing ephemeral instantiation for xlat");
                talloc_free(request);
                return -1;
        }
 
        if (unlang_function_push(request, trigger_run, trigger_resume,
                                 NULL, 0, UNLANG_TOP_FRAME, trigger) < 0) goto error;
 
        if (!intp) {
                /*
                 *      Wait for the exec to finish too,
                 *      so where there are global events
                 *      the request processes don't race
                 *      with something like the server
                 *      shutting down.
                 */
                unlang_interpret_synchronous(NULL, request);
                talloc_free(request);
        }
 
        /*
         *      Otherwise the worker cleans up the request request.
         */
        return 0;
}
 
/** Create trigger arguments to describe the server the pool connects to
 *
 * @note #trigger_exec_init must be called before calling this function,
 *       else it will return NULL.
 *
 * @param[in] ctx       to allocate fr_pair_t s in.
 * @param[out] list     to append Pool-Server and Pool-Port pairs to
 * @param[in] server    we're connecting to.
 * @param[in] port      on that server.
 */
void trigger_args_afrom_server(TALLOC_CTX *ctx, fr_pair_list_t *list, char const *server, uint16_t port)
{
        fr_dict_attr_t const    *server_da;
        fr_dict_attr_t const    *port_da;
        fr_pair_t               *vp;
 
        server_da = fr_dict_attr_child_by_num(fr_dict_root(fr_dict_internal()), FR_CONNECTION_POOL_SERVER);
        if (!server_da) {
                ERROR("Incomplete dictionary: Missing definition for \"Connection-Pool-Server\"");
                return;
        }
 
        port_da = fr_dict_attr_child_by_num(fr_dict_root(fr_dict_internal()), FR_CONNECTION_POOL_PORT);
        if (!port_da) {
                ERROR("Incomplete dictionary: Missing definition for \"Connection-Pool-Port\"");
                return;
        }
 
        MEM(vp = fr_pair_afrom_da(ctx, server_da));
        fr_pair_value_strdup(vp, server, false);
        fr_pair_append(list, vp);
 
        MEM(vp = fr_pair_afrom_da(ctx, port_da));
        vp->vp_uint16 = port;
        fr_pair_append(list, vp);
}
 
static int _mutex_free(pthread_mutex_t *mutex)
{
        pthread_mutex_destroy(mutex);
        return 0;
}
 
/** Free trigger resources
 *
 */
static int _trigger_exec_free(UNUSED void *uctx)
{
        TALLOC_FREE(trigger_last_fired_tree);
        TALLOC_FREE(trigger_mutex);
 
        return 0;
}
 
/** Set the global trigger section trigger_exec will search in, and register xlats
 *
 * This function exists because triggers are used by the connection pool, which
 * is used in the server library which may not have the mainconfig available.
 * Additionally, utilities may want to set their own root config sections.
 *
 * We don't register the trigger xlat here, as we may inadvertently initialise
 * the xlat code, which is annoying when this is called from a utility.
 *
 * @param[in] cs_arg    to use as global trigger section.
 * @return
 *      - 0 on success.
 *      - -1 on failure.
 */
static int _trigger_exec_init(void *cs_arg)
{
        CONF_SECTION *cs = talloc_get_type_abort(cs_arg, CONF_SECTION);
        if (!cs) {
                ERROR("%s - Pointer to main_config was NULL", __FUNCTION__);
                return -1;
        }
 
        trigger_exec_main = cs;
        trigger_exec_subcs = cf_section_find(cs, "trigger", NULL);
 
        if (!trigger_exec_subcs) {
                WARN("trigger { ... } subsection not found, triggers will be disabled");
                return 0;
        }
 
        MEM(trigger_last_fired_tree = fr_rb_inline_talloc_alloc(talloc_null_ctx(),
                                                                trigger_last_fired_t, node,
                                                                _trigger_last_fired_cmp, _trigger_last_fired_free));
 
        trigger_mutex = talloc(talloc_null_ctx(), pthread_mutex_t);
        pthread_mutex_init(trigger_mutex, 0);
        talloc_set_destructor(trigger_mutex, _mutex_free);
        triggers_init = true;
 
        return 0;
}
 
int trigger_exec_init(CONF_SECTION const *cs)
{
        int ret;
 
        fr_atexit_global_once_ret(&ret, _trigger_exec_init, _trigger_exec_free, UNCONST(CONF_SECTION *, cs));
 
        return ret;
}