Implement flexible state override functions

2 files changed, 90 insertions, 24 deletions

diff --git a/lib/output.c b/lib/output.c
index c408a2f5..b398c2ad 100644
--- a/lib/output.c
+++ b/lib/output.c
@@ -16,7 +16,8 @@ static mp_output_format output_format = MP_FORMAT_DEFAULT;
 static mp_output_detail_level level_of_detail = MP_DETAIL_ALL;
 
 // == Prototypes ==
-static char *fmt_subcheck_output(mp_output_format output_format, mp_subcheck check, unsigned int indentation);
+static char *fmt_subcheck_output(mp_output_format output_format, mp_subcheck check,
+                                                                 unsigned int indentation);
 static inline cJSON *json_serialize_subcheck(mp_subcheck subcheck);
 
 // == Implementation ==
@@ -58,7 +59,9 @@ static inline char *fmt_subcheck_perfdata(mp_subcheck check) {
  * It sets useful defaults
  */
 mp_check mp_check_init(void) {
-        mp_check check = {0};
+        mp_check check = {
+                .evaluation_function = &mp_eval_check_default,
+        };
         return check;
 }
 
@@ -121,7 +124,8 @@ void mp_add_perfdata_to_subcheck(mp_subcheck check[static 1], const mp_perfdata
  */
 int mp_add_subcheck_to_subcheck(mp_subcheck check[static 1], mp_subcheck subcheck) {
         if (subcheck.output == NULL) {
-                die(STATE_UNKNOWN, "%s - %s #%d: %s", __FILE__, __func__, __LINE__, "Sub check output is NULL");
+                die(STATE_UNKNOWN, "%s - %s #%d: %s", __FILE__, __func__, __LINE__,
+                        "Sub check output is NULL");
         }
 
         mp_subcheck_list *tmp = NULL;
@@ -194,18 +198,30 @@ char *get_subcheck_summary(mp_check check) {
         return result;
 }
 
+mp_state_enum mp_compute_subcheck_state(const mp_subcheck subcheck) {
+        if (subcheck.evaluation_function == NULL) {
+                return mp_eval_subcheck_default(subcheck);
+        }
+        return subcheck.evaluation_function(subcheck);
+}
+
 /*
- * Generate the result state of a mp_subcheck object based on it's own state and it's subchecks states
+ * Generate the result state of a mp_subcheck object based on its own state and its subchecks
+ * states
  */
-mp_state_enum mp_compute_subcheck_state(const mp_subcheck check) {
-        if (check.state_set_explicitly) {
-                return check.state;
+mp_state_enum mp_eval_subcheck_default(mp_subcheck subcheck) {
+        if (subcheck.evaluation_function != NULL) {
+                return subcheck.evaluation_function(subcheck);
         }
 
-        mp_subcheck_list *scl = check.subchecks;
+        if (subcheck.state_set_explicitly) {
+                return subcheck.state;
+        }
+
+        mp_subcheck_list *scl = subcheck.subchecks;
 
         if (scl == NULL) {
-                return check.default_state;
+                return subcheck.default_state;
         }
 
         mp_state_enum result = STATE_OK;
@@ -218,10 +234,18 @@ mp_state_enum mp_compute_subcheck_state(const mp_subcheck check) {
         return result;
 }
 
+mp_state_enum mp_compute_check_state(const mp_check check) {
+        // just a safety check
+        if (check.evaluation_function == NULL) {
+                return mp_eval_check_default(check);
+        }
+        return check.evaluation_function(check);
+}
+
 /*
  * Generate the result state of a mp_check object based on it's own state and it's subchecks states
  */
-mp_state_enum mp_compute_check_state(const mp_check check) {
+mp_state_enum mp_eval_check_default(const mp_check check) {
         assert(check.subchecks != NULL); // a mp_check without subchecks is invalid, die here
 
         mp_subcheck_list *scl = check.subchecks;
@@ -253,8 +277,10 @@ char *mp_fmt_output(mp_check check) {
                 mp_subcheck_list *subchecks = check.subchecks;
 
                 while (subchecks != NULL) {
-                        if (level_of_detail == MP_DETAIL_ALL || mp_compute_subcheck_state(subchecks->subcheck) != STATE_OK) {
-                                asprintf(&result, "%s\n%s", result, fmt_subcheck_output(MP_FORMAT_MULTI_LINE, subchecks->subcheck, 1));
+                        if (level_of_detail == MP_DETAIL_ALL ||
+                                mp_compute_subcheck_state(subchecks->subcheck) != STATE_OK) {
+                                asprintf(&result, "%s\n%s", result,
+                                                 fmt_subcheck_output(MP_FORMAT_MULTI_LINE, subchecks->subcheck, 1));
                         }
                         subchecks = subchecks->next;
                 }
@@ -266,7 +292,8 @@ char *mp_fmt_output(mp_check check) {
                         if (pd_string == NULL) {
                                 asprintf(&pd_string, "%s", fmt_subcheck_perfdata(subchecks->subcheck));
                         } else {
-                                asprintf(&pd_string, "%s %s", pd_string, fmt_subcheck_perfdata(subchecks->subcheck));
+                                asprintf(&pd_string, "%s %s", pd_string,
+                                                 fmt_subcheck_perfdata(subchecks->subcheck));
                         }
 
                         subchecks = subchecks->next;
@@ -335,19 +362,21 @@ static char *generate_indentation_string(unsigned int indentation) {
 /*
  * Helper function to generate the output string of mp_subcheck
  */
-static inline char *fmt_subcheck_output(mp_output_format output_format, mp_subcheck check, unsigned int indentation) {
+static inline char *fmt_subcheck_output(mp_output_format output_format, mp_subcheck check,
+                                                                                unsigned int indentation) {
         char *result = NULL;
         mp_subcheck_list *subchecks = NULL;
 
         switch (output_format) {
         case MP_FORMAT_MULTI_LINE:
-                asprintf(&result, "%s\\_[%s] - %s", generate_indentation_string(indentation), state_text(mp_compute_subcheck_state(check)),
-                                 check.output);
+                asprintf(&result, "%s\\_[%s] - %s", generate_indentation_string(indentation),
+                                 state_text(mp_compute_subcheck_state(check)), check.output);
 
                 subchecks = check.subchecks;
 
                 while (subchecks != NULL) {
-                        asprintf(&result, "%s\n%s", result, fmt_subcheck_output(output_format, subchecks->subcheck, indentation + 1));
+                        asprintf(&result, "%s\n%s", result,
+                                         fmt_subcheck_output(output_format, subchecks->subcheck, indentation + 1));
                         subchecks = subchecks->next;
                 }
                 return result;
@@ -551,3 +580,23 @@ mp_output_format mp_get_format(void) { return output_format; }
 void mp_set_level_of_detail(mp_output_detail_level level) { level_of_detail = level; }
 
 mp_output_detail_level mp_get_level_of_detail(void) { return level_of_detail; }
+
+mp_state_enum mp_eval_ok(mp_check overall) {
+        (void)overall;
+        return STATE_OK;
+}
+
+mp_state_enum mp_eval_warning(mp_check overall) {
+        (void)overall;
+        return STATE_WARNING;
+}
+
+mp_state_enum mp_eval_critical(mp_check overall) {
+        (void)overall;
+        return STATE_CRITICAL;
+}
+
+mp_state_enum mp_eval_unknown(mp_check overall) {
+        (void)overall;
+        return STATE_UNKNOWN;
+}
diff --git a/lib/output.h b/lib/output.h
index 3bd91f90..c63c8e3f 100644
--- a/lib/output.h
+++ b/lib/output.h
@@ -7,15 +7,21 @@
 /*
  * A partial check result
  */
-typedef struct {
+typedef struct mp_subcheck mp_subcheck;
+struct mp_subcheck {
         mp_state_enum state;         // OK, Warning, Critical ... set explicitly
         mp_state_enum default_state; // OK, Warning, Critical .. if not set explicitly
-        bool state_set_explicitly;   // was the state set explicitly (or should it be derived from subchecks)
+        bool state_set_explicitly;   // was the state set explicitly (or should it be derived from
+                                                                 // subchecks)
 
-        char *output;                    // Text output for humans ("Filesystem xyz is fine", "Could not create TCP connection to..")
-        pd_list *perfdata;               // Performance data for this check
+        char *output;      // Text output for humans ("Filesystem xyz is fine", "Could not create TCP
+                                           // connection to..")
+        pd_list *perfdata; // Performance data for this check
         struct subcheck_list *subchecks; // subchecks deeper in the hierarchy
-} mp_subcheck;
+
+        // the evaluation_functions computes the state of subcheck
+        mp_state_enum (*evaluation_function)(mp_subcheck);
+};
 
 /*
  * A list of subchecks, used in subchecks and the main check
@@ -57,10 +63,14 @@ mp_output_detail_level mp_get_level_of_detail(void);
  * The final result is always derived from the children and the "worst" state
  * in the first layer of subchecks
  */
-typedef struct {
+typedef struct mp_check mp_check;
+struct mp_check {
         char *summary; // Overall summary, if not set a summary will be automatically generated
         mp_subcheck_list *subchecks;
-} mp_check;
+
+        // the evaluation_functions computes the state of check
+        mp_state_enum (*evaluation_function)(mp_check);
+};
 
 mp_check mp_check_init(void);
 mp_subcheck mp_subcheck_init(void);
@@ -78,6 +88,13 @@ void mp_add_summary(mp_check check[static 1], char *summary);
 mp_state_enum mp_compute_check_state(mp_check);
 mp_state_enum mp_compute_subcheck_state(mp_subcheck);
 
+mp_state_enum mp_eval_ok(mp_check overall);
+mp_state_enum mp_eval_warning(mp_check overall);
+mp_state_enum mp_eval_critical(mp_check overall);
+mp_state_enum mp_eval_unknown(mp_check overall);
+mp_state_enum mp_eval_check_default(mp_check check);
+mp_state_enum mp_eval_subcheck_default(mp_subcheck subcheck);
+
 typedef struct {
         bool parsing_success;
         mp_output_format output_format;