Allow allocation of changed paramaters to fail, then all param functi…

…ons will return PARAM_INVALID or a count of 0

src/modules/systemlib/param/param.c

@@ -47,7 +47,6 @@
 #include <string.h>
 #include <stdbool.h>
 #include <stdlib.h>
-#include <assert.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <systemlib/err.h>
@@ -116,7 +115,13 @@ get_param_info_count(void)
 	if (!param_changed_storage) {
 		size_param_changed_storage_bytes  = (param_info_count / bits_per_allocation_unit) + 1;
 		param_changed_storage = calloc(size_param_changed_storage_bytes, 1);
-		ASSERT(param_changed_storage);
+
+		/* If the allocation fails we need to indicate failure in the
+		 * API by returning PARAM_INVALID
+		 */
+		if (param_changed_storage == NULL) {
+		    return 0;
+		}
 	}
 
 	return param_info_count;
@@ -168,7 +173,8 @@ param_assert_locked(void)
 static bool
 handle_in_range(param_t param)
 {
-	return (param < get_param_info_count());
+        int count = get_param_info_count();
+	return (count && param < count);
 }
 
 /**
@@ -248,18 +254,19 @@ param_find_internal(const char *name, bool notification)
 {
 	param_t param;
 
-	/* perform a linear search of the known parameters */
-	for (param = 0; handle_in_range(param); param++) {
-		if (!strcmp(param_info_base[param].name, name)) {
-			if (notification) {
-				param_set_used_internal(param);
-			}
+        /* perform a linear search of the known parameters */
 
-			return param;
-		}
-	}
+        for (param = 0; handle_in_range(param); param++) {
+                if (!strcmp(param_info_base[param].name, name)) {
+                        if (notification) {
+                                param_set_used_internal(param);
+                        }
 
-	/* not found */
+                        return param;
+                }
+        }
+
+        /* not found */
 	return PARAM_INVALID;
 }
 
@@ -284,38 +291,38 @@ param_count(void)
 unsigned
 param_count_used(void)
 {
-	// ensure the allocation has been done
-	get_param_info_count();
-	unsigned count = 0;
-
-	for (unsigned i = 0; i < size_param_changed_storage_bytes; i++) {
-		for (unsigned j = 0; j < bits_per_allocation_unit; j++) {
-			if (param_changed_storage[i] & (1 << j)) {
-				count++;
-			}
-		}
-	}
-
-	return count;
+  unsigned count = 0;
+
+  // ensure the allocation has been done
+  if (get_param_info_count()) {
+
+    for (unsigned i = 0; i < size_param_changed_storage_bytes; i++) {
+            for (unsigned j = 0; j < bits_per_allocation_unit; j++) {
+                    if (param_changed_storage[i] & (1 << j)) {
+                            count++;
+                    }
+            }
+    }
+  }
+  return count;
 }
 
 param_t
 param_for_index(unsigned index)
 {
-	if (index < get_param_info_count()) {
+        unsigned count = get_param_info_count();
+	if (count && index < count) {
 		return (param_t)index;
 	}
-
 	return PARAM_INVALID;
 }
 
 param_t
 param_for_used_index(unsigned index)
 {
-	if (index < get_param_info_count()) {
-
+        int count = get_param_info_count();
+        if (count && index < count) {
 		/* walk all params and count */
-		int count = 0;
 
 		for (unsigned i = 0; i < (unsigned)size_param_changed_storage_bytes; i++) {
 			for (unsigned j = 0; j < bits_per_allocation_unit; j++) {