lib/pacemaker/pcmk

/* */
This source file includes following definitions.
eval_rule
pcmk__check_rules
pcmk_check_rules
   1 /*
   2  * Copyright 2022-2024 the Pacemaker project contributors
   3  *
   4  * The version control history for this file may have further details.
   5  *
   6  * This source code is licensed under the GNU Lesser General Public License
   7  * version 2.1 or later (LGPLv2.1+) WITHOUT ANY WARRANTY.
   8  */
   9 
  10 #include <crm_internal.h>
  11 
  12 #include <crm/cib/internal.h>
  13 #include <crm/common/cib.h>
  14 #include <crm/common/iso8601.h>
  15 #include <crm/common/xml.h>
  16 #include <crm/pengine/internal.h>
  17 #include <crm/pengine/rules_internal.h>
  18 #include <pacemaker-internal.h>
  19 
  20 #include "libpacemaker_private.h"
  21 
  22 #define XPATH_NODE_RULE "//" PCMK_XE_RULE "[@" PCMK_XA_ID "='%s']"
  23 
  24 /*!
  25  * \internal
  26  * \brief Check whether a given rule is in effect
  27  *
  28  * \param[in]     scheduler  Scheduler data
  29  * \param[in]     rule_id    The ID of the rule to check
  30  * \param[out]    error      Where to store a rule evaluation error message
  31  *
  32  * \return Standard Pacemaker return code
  33  */
  34 static int
  35 eval_rule(pcmk_scheduler_t *scheduler, const char *rule_id, const char **error)
     /*  */
  36 {
  37     xmlNodePtr cib_constraints = NULL;
  38     xmlNodePtr match = NULL;
  39     xmlXPathObjectPtr xpath_obj = NULL;
  40     char *xpath = NULL;
  41     int rc = pcmk_rc_ok;
  42     int num_results = 0;
  43 
  44     *error = NULL;
  45 
  46     /* Rules are under the constraints node in the XML, so first find that. */
  47     cib_constraints = pcmk_find_cib_element(scheduler->input,
  48                                             PCMK_XE_CONSTRAINTS);
  49 
  50     /* Get all rules matching the given ID that are also simple enough for us
  51      * to check. For the moment, these rules must only have a single
  52      * date_expression child and:
  53      * - Do not have a date_spec operation, or
  54      * - Have a date_spec operation that contains years= but does not contain
  55      *   moon=.
  56      *
  57      * We do this in steps to provide better error messages. First, check that
  58      * there's any rule with the given ID.
  59      */
  60     xpath = crm_strdup_printf(XPATH_NODE_RULE, rule_id);
  61     xpath_obj = xpath_search(cib_constraints, xpath);
  62     num_results = numXpathResults(xpath_obj);
  63 
  64     free(xpath);
  65     freeXpathObject(xpath_obj);
  66 
  67     if (num_results == 0) {
  68         *error = "Rule not found";
  69         return ENXIO;
  70     }
  71 
  72     if (num_results > 1) {
  73         // Should not be possible; schema prevents this
  74         *error = "Found more than one rule with matching ID";
  75         return pcmk_rc_duplicate_id;
  76     }
  77 
  78     /* Next, make sure it has exactly one date_expression. */
  79     xpath = crm_strdup_printf(XPATH_NODE_RULE "//date_expression", rule_id);
  80     xpath_obj = xpath_search(cib_constraints, xpath);
  81     num_results = numXpathResults(xpath_obj);
  82 
  83     free(xpath);
  84     freeXpathObject(xpath_obj);
  85 
  86     if (num_results != 1) {
  87         if (num_results == 0) {
  88             *error = "Rule does not have a date expression";
  89         } else {
  90             *error = "Rule has more than one date expression";
  91         }
  92         return EOPNOTSUPP;
  93     }
  94 
  95     /* Then, check that it's something we actually support. */
  96     xpath = crm_strdup_printf(XPATH_NODE_RULE
  97                               "//" PCMK_XE_DATE_EXPRESSION
  98                               "[@" PCMK_XA_OPERATION
  99                                   "!='" PCMK_VALUE_DATE_SPEC "']",
 100                               rule_id);
 101     xpath_obj = xpath_search(cib_constraints, xpath);
 102     num_results = numXpathResults(xpath_obj);
 103 
 104     free(xpath);
 105 
 106     if (num_results == 0) {
 107         freeXpathObject(xpath_obj);
 108 
 109         xpath = crm_strdup_printf(XPATH_NODE_RULE
 110                                   "//" PCMK_XE_DATE_EXPRESSION
 111                                   "[@" PCMK_XA_OPERATION
 112                                       "='" PCMK_VALUE_DATE_SPEC "' "
 113                                   "and " PCMK_XE_DATE_SPEC
 114                                       "/@" PCMK_XA_YEARS " "
 115                                   "and not(" PCMK_XE_DATE_SPEC
 116                                       "/@" PCMK__XA_MOON ")]",
 117                                   rule_id);
 118         xpath_obj = xpath_search(cib_constraints, xpath);
 119         num_results = numXpathResults(xpath_obj);
 120 
 121         free(xpath);
 122 
 123         if (num_results == 0) {
 124             freeXpathObject(xpath_obj);
 125             *error = "Rule must either not use " PCMK_XE_DATE_SPEC ", or use "
 126                      PCMK_XE_DATE_SPEC " with " PCMK_XA_YEARS "= but not "
 127                      PCMK__XA_MOON "=";
 128             return EOPNOTSUPP;
 129         }
 130     }
 131 
 132     match = getXpathResult(xpath_obj, 0);
 133 
 134     /* We should have ensured this with the xpath query above, but double-
 135      * checking can't hurt.
 136      */
 137     CRM_ASSERT(match != NULL);
 138     CRM_ASSERT(pcmk__condition_type(match) == pcmk__condition_datetime);
 139 
 140     rc = pcmk__evaluate_date_expression(match, scheduler->now, NULL);
 141     if (rc == pcmk_rc_undetermined) { // Malformed or missing
 142         *error = "Error parsing rule";
 143     }
 144 
 145     freeXpathObject(xpath_obj);
 146     return rc;
 147 }
 148 
 149 /*!
 150  * \internal
 151  * \brief Check whether each rule in a list is in effect
 152  *
 153  * \param[in,out] out       Output object
 154  * \param[in]     input     The CIB XML to check (if \c NULL, use current CIB)
 155  * \param[in]     date      Check whether the rule is in effect at this date and
 156  *                          time (if \c NULL, use current date and time)
 157  * \param[in]     rule_ids  The IDs of the rules to check, as a <tt>NULL</tt>-
 158  *                          terminated list.
 159  *
 160  * \return Standard Pacemaker return code
 161  */
 162 int
 163 pcmk__check_rules(pcmk__output_t *out, xmlNodePtr input, const crm_time_t *date,
     /*  */
 164                   const char **rule_ids)
 165 {
 166     pcmk_scheduler_t *scheduler = NULL;
 167     int rc = pcmk_rc_ok;
 168 
 169     CRM_ASSERT(out != NULL);
 170 
 171     if (rule_ids == NULL) {
 172         // Trivial case; every rule specified is in effect
 173         return pcmk_rc_ok;
 174     }
 175 
 176     rc = pcmk__init_scheduler(out, input, date, &scheduler);
 177     if (rc != pcmk_rc_ok) {
 178         return rc;
 179     }
 180 
 181     for (const char **rule_id = rule_ids; *rule_id != NULL; rule_id++) {
 182         const char *error = NULL;
 183         int last_rc = eval_rule(scheduler, *rule_id, &error);
 184 
 185         out->message(out, "rule-check", *rule_id, last_rc, error);
 186 
 187         if (last_rc != pcmk_rc_ok) {
 188             rc = last_rc;
 189         }
 190     }
 191 
 192     pe_free_working_set(scheduler);
 193     return rc;
 194 }
 195 
 196 // Documented in pacemaker.h
 197 int
 198 pcmk_check_rules(xmlNodePtr *xml, xmlNodePtr input, const crm_time_t *date,
     /*  */
 199                  const char **rule_ids)
 200 {
 201     pcmk__output_t *out = NULL;
 202     int rc = pcmk_rc_ok;
 203 
 204     rc = pcmk__xml_output_new(&out, xml);
 205     if (rc != pcmk_rc_ok) {
 206         return rc;
 207     }
 208 
 209     pcmk__register_lib_messages(out);
 210 
 211     rc = pcmk__check_rules(out, input, date, rule_ids);
 212     pcmk__xml_output_finish(out, pcmk_rc2exitc(rc), xml);
 213     return rc;
 214 }
/* */
root/lib/pacemaker/pcmk_rule.c

DEFINITIONS
