18a2d737cSLawrence Tang /** 28a2d737cSLawrence Tang * A very basic, non-complete implementation of a validator for the JSON Schema specification, 38a2d737cSLawrence Tang * for validating CPER-JSON. 48a2d737cSLawrence Tang * 58a2d737cSLawrence Tang * Author: Lawrence.Tang@arm.com 68a2d737cSLawrence Tang **/ 78a2d737cSLawrence Tang 88a2d737cSLawrence Tang #include <stdio.h> 98a2d737cSLawrence Tang #include <string.h> 108a2d737cSLawrence Tang #include <unistd.h> 118a2d737cSLawrence Tang #include <libgen.h> 128a2d737cSLawrence Tang #include <limits.h> 138a2d737cSLawrence Tang #include "json.h" 148a2d737cSLawrence Tang #include "json-schema.h" 158a2d737cSLawrence Tang #include "edk/BaseTypes.h" 168a2d737cSLawrence Tang 178a2d737cSLawrence Tang //Private pre-definitions. 188a2d737cSLawrence Tang int validate_field(const char* name, json_object* schema, json_object* object, char* error_message); 198a2d737cSLawrence Tang int validate_integer(const char* field_name, json_object* schema, json_object* object, char* error_message); 208a2d737cSLawrence Tang int validate_string(const char* field_name, json_object* schema, json_object* object, char* error_message); 218a2d737cSLawrence Tang int validate_object(const char* field_name, json_object* schema, json_object* object, char* error_message); 228a2d737cSLawrence Tang int validate_array(const char* field_name, json_object* schema, json_object* object, char* error_message); 238a2d737cSLawrence Tang 248a2d737cSLawrence Tang //Validates a single JSON object against a provided schema file, returning 1 on success and 0 on failure to validate. 258a2d737cSLawrence Tang //Error message space must be allocated prior to call. 268a2d737cSLawrence Tang int validate_schema_from_file(const char* schema_file, json_object* object, char* error_message) 278a2d737cSLawrence Tang { 288a2d737cSLawrence Tang //Load schema IR from file. 298a2d737cSLawrence Tang json_object* schema_ir = json_object_from_file(schema_file); 308a2d737cSLawrence Tang if (schema_ir == NULL) 318a2d737cSLawrence Tang { 328a2d737cSLawrence Tang sprintf(error_message, "Failed to load schema from file '%s'.", schema_file); 338a2d737cSLawrence Tang return 0; 348a2d737cSLawrence Tang } 358a2d737cSLawrence Tang 368a2d737cSLawrence Tang //Get the directory of the file. 378a2d737cSLawrence Tang char* schema_file_copy = malloc(strlen(schema_file) + 1); 388a2d737cSLawrence Tang strcpy(schema_file_copy, schema_file); 398a2d737cSLawrence Tang char* schema_dir = dirname(schema_file_copy); 408a2d737cSLawrence Tang 418a2d737cSLawrence Tang int result = validate_schema(schema_ir, schema_dir, object, error_message); 428a2d737cSLawrence Tang 438a2d737cSLawrence Tang //Free memory from directory call. 448a2d737cSLawrence Tang free(schema_file_copy); 458a2d737cSLawrence Tang 468a2d737cSLawrence Tang return result; 478a2d737cSLawrence Tang } 488a2d737cSLawrence Tang 498a2d737cSLawrence Tang //Validates a single JSON object against a provided schema, returning 1 on success and 0 on failure to validate. 508a2d737cSLawrence Tang //Error message space must be allocated prior to call. 518a2d737cSLawrence Tang //If the schema does not include any other sub-schemas using "$ref", then leaving schema_directory as NULL is valid. 528a2d737cSLawrence Tang int validate_schema(json_object* schema, char* schema_directory, json_object* object, char* error_message) 538a2d737cSLawrence Tang { 548a2d737cSLawrence Tang //Check that the schema version is the same as this validator. 558a2d737cSLawrence Tang json_object* schema_ver = json_object_object_get(schema, "$schema"); 568a2d737cSLawrence Tang if (schema_ver == NULL || strcmp(json_object_get_string(schema_ver), JSON_SCHEMA_VERSION)) 578a2d737cSLawrence Tang { 588a2d737cSLawrence Tang sprintf(error_message, "Provided schema is not of the same version that is referenced by this validator, or is not a schema."); 598a2d737cSLawrence Tang return 0; 608a2d737cSLawrence Tang } 618a2d737cSLawrence Tang 628a2d737cSLawrence Tang //Change current directory into the schema directory. 638a2d737cSLawrence Tang char* original_cwd = malloc(PATH_MAX); 648a2d737cSLawrence Tang if (getcwd(original_cwd, PATH_MAX) == NULL) 658a2d737cSLawrence Tang { 668a2d737cSLawrence Tang sprintf(error_message, "Failed fetching the current directory."); 678a2d737cSLawrence Tang return 0; 688a2d737cSLawrence Tang } 698a2d737cSLawrence Tang if (chdir(schema_directory)) 708a2d737cSLawrence Tang { 718a2d737cSLawrence Tang sprintf(error_message, "Failed to chdir into schema directory."); 728a2d737cSLawrence Tang return 0; 738a2d737cSLawrence Tang } 748a2d737cSLawrence Tang 758a2d737cSLawrence Tang //Parse the top level structure appropriately. 768a2d737cSLawrence Tang int result = validate_field("parent", schema, object, error_message); 778a2d737cSLawrence Tang 788a2d737cSLawrence Tang //Change back to original CWD. 798a2d737cSLawrence Tang chdir(original_cwd); 808a2d737cSLawrence Tang free(original_cwd); 818a2d737cSLawrence Tang 828a2d737cSLawrence Tang return result; 838a2d737cSLawrence Tang } 848a2d737cSLawrence Tang 858a2d737cSLawrence Tang //Validates a single JSON field given a schema/object. 868a2d737cSLawrence Tang int validate_field(const char* field_name, json_object* schema, json_object* object, char* error_message) 878a2d737cSLawrence Tang { 888a2d737cSLawrence Tang //If there is a "$ref" field, attempt to load the referenced schema. 898a2d737cSLawrence Tang json_object* ref_schema = json_object_object_get(schema, "$ref"); 908a2d737cSLawrence Tang if (ref_schema != NULL && json_object_get_type(ref_schema) == json_type_string) 918a2d737cSLawrence Tang { 928a2d737cSLawrence Tang //Attempt to load. If loading fails, report error. 938a2d737cSLawrence Tang const char* ref_path = json_object_get_string(ref_schema); 948a2d737cSLawrence Tang schema = json_object_from_file(ref_path); 958a2d737cSLawrence Tang if (schema == NULL) 968a2d737cSLawrence Tang { 978a2d737cSLawrence Tang sprintf(error_message, "Failed to open referenced schema file '%s'.", ref_path); 988a2d737cSLawrence Tang return 0; 998a2d737cSLawrence Tang } 1008a2d737cSLawrence Tang } 1018a2d737cSLawrence Tang 1028a2d737cSLawrence Tang //Get the schema field type. 1038a2d737cSLawrence Tang json_object* desired_field_type = json_object_object_get(schema, "type"); 1048a2d737cSLawrence Tang if (desired_field_type == NULL || !json_object_is_type(desired_field_type, json_type_string)) 1058a2d737cSLawrence Tang { 1068a2d737cSLawrence Tang sprintf(error_message, "Desired field type not provided within schema/is not a string for field '%s' (schema violation).", field_name); 1078a2d737cSLawrence Tang return 0; 1088a2d737cSLawrence Tang } 1098a2d737cSLawrence Tang 1108a2d737cSLawrence Tang //Check the field types are actually equal. 1118a2d737cSLawrence Tang const char* desired_field_type_str = json_object_get_string(desired_field_type); 1128a2d737cSLawrence Tang if (!( 1138a2d737cSLawrence Tang (!strcmp(desired_field_type_str, "object") && json_object_is_type(object, json_type_object)) 1148a2d737cSLawrence Tang || (!strcmp(desired_field_type_str, "array") && json_object_is_type(object, json_type_array)) 1158a2d737cSLawrence Tang || (!strcmp(desired_field_type_str, "integer") && json_object_is_type(object, json_type_int)) 1168a2d737cSLawrence Tang || (!strcmp(desired_field_type_str, "string") && json_object_is_type(object, json_type_string)) 1178a2d737cSLawrence Tang || (!strcmp(desired_field_type_str, "boolean") && json_object_is_type(object, json_type_boolean)) 1188a2d737cSLawrence Tang || (!strcmp(desired_field_type_str, "double") && json_object_is_type(object, json_type_double)) 1198a2d737cSLawrence Tang )) 1208a2d737cSLawrence Tang { 1218a2d737cSLawrence Tang sprintf(error_message, "Field type match failed for field '%s'.", field_name); 1228a2d737cSLawrence Tang return 0; 1238a2d737cSLawrence Tang } 1248a2d737cSLawrence Tang 125*45e04b0aSLawrence Tang //todo: support oneOf 126*45e04b0aSLawrence Tang 1278a2d737cSLawrence Tang //Switch and validate each type in turn. 1288a2d737cSLawrence Tang switch (json_object_get_type(object)) 1298a2d737cSLawrence Tang { 1308a2d737cSLawrence Tang case json_type_int: 1318a2d737cSLawrence Tang return validate_integer(field_name, schema, object, error_message); 1328a2d737cSLawrence Tang case json_type_string: 1338a2d737cSLawrence Tang return validate_string(field_name, schema, object, error_message); 1348a2d737cSLawrence Tang case json_type_object: 1358a2d737cSLawrence Tang return validate_object(field_name, schema, object, error_message); 1368a2d737cSLawrence Tang case json_type_array: 1378a2d737cSLawrence Tang return validate_object(field_name, schema, object, error_message); 1388a2d737cSLawrence Tang 1398a2d737cSLawrence Tang //We don't perform extra validation on this type. 1408a2d737cSLawrence Tang default: 1418a2d737cSLawrence Tang return 1; 1428a2d737cSLawrence Tang } 1438a2d737cSLawrence Tang } 1448a2d737cSLawrence Tang 1458a2d737cSLawrence Tang //Validates a single integer value according to the given specification. 1468a2d737cSLawrence Tang int validate_integer(const char* field_name, json_object* schema, json_object* object, char* error_message) 1478a2d737cSLawrence Tang { 1488a2d737cSLawrence Tang //Is there a minimum/maximum specified? If so, check those. 1498a2d737cSLawrence Tang //Validate minimum. 1508a2d737cSLawrence Tang json_object* min_value = json_object_object_get(schema, "minimum"); 1518a2d737cSLawrence Tang if (min_value != NULL && json_object_is_type(min_value, json_type_int)) 1528a2d737cSLawrence Tang { 1538a2d737cSLawrence Tang int min_value_int = json_object_get_int(min_value); 1548a2d737cSLawrence Tang if (json_object_get_uint64(object) < min_value_int) 1558a2d737cSLawrence Tang { 1568a2d737cSLawrence Tang sprintf(error_message, "Failed to validate integer field '%s'. Value was below minimum of %d.", field_name, min_value_int); 1578a2d737cSLawrence Tang return 0; 1588a2d737cSLawrence Tang } 1598a2d737cSLawrence Tang } 1608a2d737cSLawrence Tang 1618a2d737cSLawrence Tang //Validate maximum. 1628a2d737cSLawrence Tang json_object* max_value = json_object_object_get(schema, "maximum"); 1638a2d737cSLawrence Tang if (max_value != NULL && json_object_is_type(max_value, json_type_int)) 1648a2d737cSLawrence Tang { 1658a2d737cSLawrence Tang int max_value_int = json_object_get_int(max_value); 1668a2d737cSLawrence Tang if (json_object_get_uint64(object) > max_value_int) 1678a2d737cSLawrence Tang { 1688a2d737cSLawrence Tang sprintf(error_message, "Failed to validate integer field '%s'. Value was above maximum of %d.", field_name, max_value_int); 1698a2d737cSLawrence Tang return 0; 1708a2d737cSLawrence Tang } 1718a2d737cSLawrence Tang } 1728a2d737cSLawrence Tang 1738a2d737cSLawrence Tang return 1; 1748a2d737cSLawrence Tang } 1758a2d737cSLawrence Tang 1768a2d737cSLawrence Tang //Validates a single string value according to the given specification. 1778a2d737cSLawrence Tang int validate_string(const char* field_name, json_object* schema, json_object* object, char* error_message) 1788a2d737cSLawrence Tang { 1798a2d737cSLawrence Tang //todo: if there is a "pattern" field, verify the string with RegEx. 1808a2d737cSLawrence Tang return 1; 1818a2d737cSLawrence Tang } 1828a2d737cSLawrence Tang 1838a2d737cSLawrence Tang //Validates a single object value according to the given specification. 1848a2d737cSLawrence Tang int validate_object(const char* field_name, json_object* schema, json_object* object, char* error_message) 1858a2d737cSLawrence Tang { 1868a2d737cSLawrence Tang //Are there a set of "required" fields? If so, check they all exist. 1878a2d737cSLawrence Tang json_object* required_fields = json_object_object_get(schema, "required"); 1888a2d737cSLawrence Tang if (required_fields != NULL && json_object_get_type(required_fields) == json_type_array) 1898a2d737cSLawrence Tang { 1908a2d737cSLawrence Tang int len = json_object_array_length(required_fields); 1918a2d737cSLawrence Tang for (int i=0; i<len; i++) 1928a2d737cSLawrence Tang { 1938a2d737cSLawrence Tang //Get the required field from schema. 1948a2d737cSLawrence Tang json_object* required_field = json_object_array_get_idx(required_fields, i); 1958a2d737cSLawrence Tang if (json_object_get_type(required_field) != json_type_string) 1968a2d737cSLawrence Tang { 1978a2d737cSLawrence Tang sprintf(error_message, "Required field for object '%s' is not a string (schema violation).", field_name); 1988a2d737cSLawrence Tang return 0; 1998a2d737cSLawrence Tang } 2008a2d737cSLawrence Tang 2018a2d737cSLawrence Tang //Does it exist in the object? 2028a2d737cSLawrence Tang const char* required_field_str = json_object_get_string(required_field); 2038a2d737cSLawrence Tang if (json_object_object_get(object, required_field_str) == NULL) 2048a2d737cSLawrence Tang { 2058a2d737cSLawrence Tang sprintf(error_message, "Required field '%s' was not present in object '%s'.", required_field_str, field_name); 2068a2d737cSLawrence Tang return 0; 2078a2d737cSLawrence Tang } 2088a2d737cSLawrence Tang } 2098a2d737cSLawrence Tang } 2108a2d737cSLawrence Tang 2118a2d737cSLawrence Tang //If the boolean field "additionalProperties" exists and is set to false, ensure there are no 2128a2d737cSLawrence Tang //extra properties apart from those required in the object. 2138a2d737cSLawrence Tang //... todo 2148a2d737cSLawrence Tang 2158a2d737cSLawrence Tang //Run through the "properties" object and validate each of those in turn. 2168a2d737cSLawrence Tang json_object* properties = json_object_object_get(schema, "properties"); 2178a2d737cSLawrence Tang if (properties != NULL && json_object_get_type(properties) == json_type_object) 2188a2d737cSLawrence Tang { 2198a2d737cSLawrence Tang json_object_object_foreach(properties, key, value) { 2208a2d737cSLawrence Tang 2218a2d737cSLawrence Tang //If the given property name does not exist on the target object, ignore and continue next. 2228a2d737cSLawrence Tang json_object* object_prop = json_object_object_get(object, key); 2238a2d737cSLawrence Tang if (object_prop == NULL) 2248a2d737cSLawrence Tang continue; 2258a2d737cSLawrence Tang 2268a2d737cSLawrence Tang //Validate against the schema. 2278a2d737cSLawrence Tang if (!validate_field(key, value, object_prop, error_message)) 2288a2d737cSLawrence Tang return 0; 2298a2d737cSLawrence Tang } 2308a2d737cSLawrence Tang } 2318a2d737cSLawrence Tang 2328a2d737cSLawrence Tang return 1; 2338a2d737cSLawrence Tang } 2348a2d737cSLawrence Tang 2358a2d737cSLawrence Tang //Validates a single array value according to the given specification. 2368a2d737cSLawrence Tang int validate_array(const char* field_name, json_object* schema, json_object* object, char* error_message) 2378a2d737cSLawrence Tang { 238*45e04b0aSLawrence Tang //Iterate all items in the array, and validate according to the "items" schema. 239*45e04b0aSLawrence Tang json_object* items_schema = json_object_object_get(schema, "items"); 240*45e04b0aSLawrence Tang if (items_schema != NULL && json_object_get_type(items_schema) == json_type_object) 241*45e04b0aSLawrence Tang { 242*45e04b0aSLawrence Tang int array_len = json_object_array_length(object); 243*45e04b0aSLawrence Tang for (int i=0; i<array_len; i++) 244*45e04b0aSLawrence Tang { 245*45e04b0aSLawrence Tang if (!validate_field(field_name, items_schema, json_object_array_get_idx(object, i), error_message)) 246*45e04b0aSLawrence Tang return 0; 247*45e04b0aSLawrence Tang } 248*45e04b0aSLawrence Tang } 249*45e04b0aSLawrence Tang 2508a2d737cSLawrence Tang return 1; 2518a2d737cSLawrence Tang }