src/shared/json.h

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 #pragma once
   3
   4 #include <fcntl.h>
   5 #include <stdbool.h>
   6 #include <stddef.h>
   7 #include <stdint.h>
   8 #include <stdio.h>
   9
  10 #include "macro.h"
  11 #include "string-util.h"
  12 #include "log.h"
  13
  14 /*
  15   In case you wonder why we have our own JSON implementation, here are a couple of reasons why this implementation has
  16   benefits over various other implementations:
  17
  18   - We need support for 64bit signed and unsigned integers, i.e. the full 64,5bit range of -9223372036854775808…18446744073709551615
  19   - All our variants are immutable after creation
  20   - Special values such as true, false, zero, null, empty strings, empty array, empty objects require zero dynamic memory
  21   - Progressive parsing
  22   - Our integer/real type implicitly converts, but only if that's safe and loss-lessly possible
  23   - There's a "builder" for putting together objects easily in varargs function calls
  24   - There's a "dispatcher" for mapping objects to C data structures
  25   - Every variant optionally carries parsing location information, which simplifies debugging and parse log error generation
  26   - Formatter has color, line, column support
  27
  28   Limitations:
  29   - Doesn't allow embedded NUL in strings
  30   - Can't store integers outside of the -9223372036854775808…18446744073709551615 range (it will use 'long double' for
  31     values outside this range, which is lossy)
  32   - Can't store negative zero (will be treated identical to positive zero, and not retained across serialization)
  33   - Can't store non-integer numbers that can't be stored in "long double" losslessly
  34   - Allows creation and parsing of objects with duplicate keys. The "dispatcher" will refuse them however. This means
  35     we can parse and pass around such objects, but will carefully refuse them when we convert them into our own data.
  36
  37   (These limitations should be pretty much in line with those of other JSON implementations, in fact might be less
  38   limiting in most cases even.)
  39 */
  40
  41 typedef struct JsonVariant JsonVariant;
  42
  43 typedef enum JsonVariantType {
  44         JSON_VARIANT_STRING,
  45         JSON_VARIANT_INTEGER,
  46         JSON_VARIANT_UNSIGNED,
  47         JSON_VARIANT_REAL,
  48         JSON_VARIANT_NUMBER, /* This a pseudo-type: we can never create variants of this type, but we use it as wildcard check for the above three types */
  49         JSON_VARIANT_BOOLEAN,
  50         JSON_VARIANT_ARRAY,
  51         JSON_VARIANT_OBJECT,
  52         JSON_VARIANT_NULL,
  53         _JSON_VARIANT_TYPE_MAX,
  54         _JSON_VARIANT_TYPE_INVALID = -1
  55 } JsonVariantType;
  56
  57 int json_variant_new_stringn(JsonVariant **ret, const char *s, size_t n);
  58 int json_variant_new_base64(JsonVariant **ret, const void *p, size_t n);
  59 int json_variant_new_integer(JsonVariant **ret, intmax_t i);
  60 int json_variant_new_unsigned(JsonVariant **ret, uintmax_t u);
  61 int json_variant_new_real(JsonVariant **ret, long double d);
  62 int json_variant_new_boolean(JsonVariant **ret, bool b);
  63 int json_variant_new_array(JsonVariant **ret, JsonVariant **array, size_t n);
  64 int json_variant_new_array_bytes(JsonVariant **ret, const void *p, size_t n);
  65 int json_variant_new_array_strv(JsonVariant **ret, char **l);
  66 int json_variant_new_object(JsonVariant **ret, JsonVariant **array, size_t n);
  67 int json_variant_new_null(JsonVariant **ret);
  68
  69 static inline int json_variant_new_string(JsonVariant **ret, const char *s) {
  70         return json_variant_new_stringn(ret, s, (size_t) -1);
  71 }
  72
  73 JsonVariant *json_variant_ref(JsonVariant *v);
  74 JsonVariant *json_variant_unref(JsonVariant *v);
  75 void json_variant_unref_many(JsonVariant **array, size_t n);
  76
  77 DEFINE_TRIVIAL_CLEANUP_FUNC(JsonVariant *, json_variant_unref);
  78
  79 const char *json_variant_string(JsonVariant *v);
  80 intmax_t json_variant_integer(JsonVariant *v);
  81 uintmax_t json_variant_unsigned(JsonVariant *v);
  82 long double json_variant_real(JsonVariant *v);
  83 bool json_variant_boolean(JsonVariant *v);
  84
  85 JsonVariantType json_variant_type(JsonVariant *v);
  86 bool json_variant_has_type(JsonVariant *v, JsonVariantType type);
  87
  88 static inline bool json_variant_is_string(JsonVariant *v) {
  89         return json_variant_has_type(v, JSON_VARIANT_STRING);
  90 }
  91
  92 static inline bool json_variant_is_integer(JsonVariant *v) {
  93         return json_variant_has_type(v, JSON_VARIANT_INTEGER);
  94 }
  95
  96 static inline bool json_variant_is_unsigned(JsonVariant *v) {
  97         return json_variant_has_type(v, JSON_VARIANT_UNSIGNED);
  98 }
  99
 100 static inline bool json_variant_is_real(JsonVariant *v) {
 101         return json_variant_has_type(v, JSON_VARIANT_REAL);
 102 }
 103
 104 static inline bool json_variant_is_number(JsonVariant *v) {
 105         return json_variant_has_type(v, JSON_VARIANT_NUMBER);
 106 }
 107
 108 static inline bool json_variant_is_boolean(JsonVariant *v) {
 109         return json_variant_has_type(v, JSON_VARIANT_BOOLEAN);
 110 }
 111
 112 static inline bool json_variant_is_array(JsonVariant *v) {
 113         return json_variant_has_type(v, JSON_VARIANT_ARRAY);
 114 }
 115
 116 static inline bool json_variant_is_object(JsonVariant *v) {
 117         return json_variant_has_type(v, JSON_VARIANT_OBJECT);
 118 }
 119
 120 static inline bool json_variant_is_null(JsonVariant *v) {
 121         return json_variant_has_type(v, JSON_VARIANT_NULL);
 122 }
 123
 124 bool json_variant_is_negative(JsonVariant *v);
 125 bool json_variant_is_blank_object(JsonVariant *v);
 126 bool json_variant_is_blank_array(JsonVariant *v);
 127 bool json_variant_is_normalized(JsonVariant *v);
 128 bool json_variant_is_sorted(JsonVariant *v);
 129
 130 size_t json_variant_elements(JsonVariant *v);
 131 JsonVariant *json_variant_by_index(JsonVariant *v, size_t index);
 132 JsonVariant *json_variant_by_key(JsonVariant *v, const char *key);
 133 JsonVariant *json_variant_by_key_full(JsonVariant *v, const char *key, JsonVariant **ret_key);
 134
 135 bool json_variant_equal(JsonVariant *a, JsonVariant *b);
 136
 137 void json_variant_sensitive(JsonVariant *v);
 138
 139 struct json_variant_foreach_state {
 140         JsonVariant *variant;
 141         size_t idx;
 142 };
 143
 144 #define JSON_VARIANT_ARRAY_FOREACH(i, v)                                \
 145         for (struct json_variant_foreach_state _state = { (v), 0 };     \
 146              json_variant_is_array(_state.variant) &&                   \
 147                      _state.idx < json_variant_elements(_state.variant) && \
 148                      ({ i = json_variant_by_index(_state.variant, _state.idx); \
 149                              true; });                                  \
 150              _state.idx++)
 151
 152 #define JSON_VARIANT_OBJECT_FOREACH(k, e, v)                            \
 153         for (struct json_variant_foreach_state _state = { (v), 0 };     \
 154              json_variant_is_object(_state.variant) &&                  \
 155                      _state.idx < json_variant_elements(_state.variant) && \
 156                      ({ k = json_variant_string(json_variant_by_index(_state.variant, _state.idx)); \
 157                              e = json_variant_by_index(_state.variant, _state.idx + 1); \
 158                              true; });                                  \
 159              _state.idx += 2)
 160
 161 int json_variant_get_source(JsonVariant *v, const char **ret_source, unsigned *ret_line, unsigned *ret_column);
 162
 163 typedef enum JsonFormatFlags {
 164         JSON_FORMAT_NEWLINE     = 1 << 0, /* suffix with newline */
 165         JSON_FORMAT_PRETTY      = 1 << 1, /* add internal whitespace to appeal to human readers */
 166         JSON_FORMAT_PRETTY_AUTO = 1 << 2, /* same, but only if connected to a tty (and JSON_FORMAT_NEWLINE otherwise) */
 167         JSON_FORMAT_COLOR       = 1 << 3, /* insert ANSI color sequences */
 168         JSON_FORMAT_COLOR_AUTO  = 1 << 4, /* insert ANSI color sequences if colors_enabled() says so */
 169         JSON_FORMAT_SOURCE      = 1 << 5, /* prefix with source filename/line/column */
 170         JSON_FORMAT_SSE         = 1 << 6, /* prefix/suffix with W3C server-sent events */
 171         JSON_FORMAT_SEQ         = 1 << 7, /* prefix/suffix with RFC 7464 application/json-seq */
 172         JSON_FORMAT_FLUSH       = 1 << 8, /* call fflush() after dumping JSON */
 173 } JsonFormatFlags;
 174
 175 int json_variant_format(JsonVariant *v, JsonFormatFlags flags, char **ret);
 176 void json_variant_dump(JsonVariant *v, JsonFormatFlags flags, FILE *f, const char *prefix);
 177
 178 int json_variant_filter(JsonVariant **v, char **to_remove);
 179
 180 int json_variant_set_field(JsonVariant **v, const char *field, JsonVariant *value);
 181 int json_variant_set_field_string(JsonVariant **v, const char *field, const char *value);
 182 int json_variant_set_field_integer(JsonVariant **v, const char *field, intmax_t value);
 183 int json_variant_set_field_unsigned(JsonVariant **v, const char *field, uintmax_t value);
 184 int json_variant_set_field_boolean(JsonVariant **v, const char *field, bool b);
 185
 186 int json_variant_append_array(JsonVariant **v, JsonVariant *element);
 187
 188 int json_variant_merge(JsonVariant **v, JsonVariant *m);
 189
 190 int json_variant_strv(JsonVariant *v, char ***ret);
 191
 192 int json_variant_sort(JsonVariant **v);
 193 int json_variant_normalize(JsonVariant **v);
 194
 195 typedef enum JsonParseFlags {
 196         JSON_PARSE_SENSITIVE = 1 << 0, /* mark variant as "sensitive", i.e. something containing secret key material or such */
 197 } JsonParseFlags;
 198
 199 int json_parse(const char *string, JsonParseFlags flags, JsonVariant **ret, unsigned *ret_line, unsigned *ret_column);
 200 int json_parse_continue(const char **p, JsonParseFlags flags, JsonVariant **ret, unsigned *ret_line, unsigned *ret_column);
 201 int json_parse_file_at(FILE *f, int dir_fd, const char *path, JsonParseFlags flags, JsonVariant **ret, unsigned *ret_line, unsigned *ret_column);
 202
 203 static inline int json_parse_file(FILE *f, const char *path, JsonParseFlags flags, JsonVariant **ret, unsigned *ret_line, unsigned *ret_column) {
 204         return json_parse_file_at(f, AT_FDCWD, path, flags, ret, ret_line, ret_column);
 205 }
 206
 207 enum {
 208         _JSON_BUILD_STRING,
 209         _JSON_BUILD_INTEGER,
 210         _JSON_BUILD_UNSIGNED,
 211         _JSON_BUILD_REAL,
 212         _JSON_BUILD_BOOLEAN,
 213         _JSON_BUILD_ARRAY_BEGIN,
 214         _JSON_BUILD_ARRAY_END,
 215         _JSON_BUILD_OBJECT_BEGIN,
 216         _JSON_BUILD_OBJECT_END,
 217         _JSON_BUILD_PAIR,
 218         _JSON_BUILD_PAIR_CONDITION,
 219         _JSON_BUILD_NULL,
 220         _JSON_BUILD_VARIANT,
 221         _JSON_BUILD_VARIANT_ARRAY,
 222         _JSON_BUILD_LITERAL,
 223         _JSON_BUILD_STRV,
 224         _JSON_BUILD_BASE64,
 225         _JSON_BUILD_MAX,
 226 };
 227
 228 #define JSON_BUILD_STRING(s) _JSON_BUILD_STRING, ({ const char *_x = s; _x; })
 229 #define JSON_BUILD_INTEGER(i) _JSON_BUILD_INTEGER, ({ intmax_t _x = i; _x; })
 230 #define JSON_BUILD_UNSIGNED(u) _JSON_BUILD_UNSIGNED, ({ uintmax_t _x = u; _x; })
 231 #define JSON_BUILD_REAL(d) _JSON_BUILD_REAL, ({ long double _x = d; _x; })
 232 #define JSON_BUILD_BOOLEAN(b) _JSON_BUILD_BOOLEAN, ({ bool _x = b; _x; })
 233 #define JSON_BUILD_ARRAY(...) _JSON_BUILD_ARRAY_BEGIN, __VA_ARGS__, _JSON_BUILD_ARRAY_END
 234 #define JSON_BUILD_EMPTY_ARRAY _JSON_BUILD_ARRAY_BEGIN, _JSON_BUILD_ARRAY_END
 235 #define JSON_BUILD_OBJECT(...) _JSON_BUILD_OBJECT_BEGIN, __VA_ARGS__, _JSON_BUILD_OBJECT_END
 236 #define JSON_BUILD_EMPTY_OBJECT _JSON_BUILD_OBJECT_BEGIN, _JSON_BUILD_OBJECT_END
 237 #define JSON_BUILD_PAIR(n, ...) _JSON_BUILD_PAIR, ({ const char *_x = n; _x; }), __VA_ARGS__
 238 #define JSON_BUILD_PAIR_CONDITION(c, n, ...) _JSON_BUILD_PAIR_CONDITION, ({ bool _x = c; _x; }), ({ const char *_x = n; _x; }), __VA_ARGS__
 239 #define JSON_BUILD_NULL _JSON_BUILD_NULL
 240 #define JSON_BUILD_VARIANT(v) _JSON_BUILD_VARIANT, ({ JsonVariant *_x = v; _x; })
 241 #define JSON_BUILD_VARIANT_ARRAY(v, n) _JSON_BUILD_VARIANT_ARRAY, ({ JsonVariant **_x = v; _x; }), ({ size_t _y = n; _y; })
 242 #define JSON_BUILD_LITERAL(l) _JSON_BUILD_LITERAL, ({ const char *_x = l; _x; })
 243 #define JSON_BUILD_STRV(l) _JSON_BUILD_STRV, ({ char **_x = l; _x; })
 244 #define JSON_BUILD_BASE64(p, n) _JSON_BUILD_BASE64, ({ const void *_x = p; _x; }), ({ size_t _y = n; _y; })
 245
 246 int json_build(JsonVariant **ret, ...);
 247 int json_buildv(JsonVariant **ret, va_list ap);
 248
 249 /* A bitmask of flags used by the dispatch logic. Note that this is a combined bit mask, that is generated from the bit
 250  * mask originally passed into json_dispatch(), the individual bitmask associated with the static JsonDispatch callout
 251  * entry, as well the bitmask specified for json_log() calls */
 252 typedef enum JsonDispatchFlags {
 253         /* The following three may be set in JsonDispatch's .flags field or the json_dispatch() flags parameter  */
 254         JSON_PERMISSIVE = 1 << 0, /* Shall parsing errors be considered fatal for this property? */
 255         JSON_MANDATORY  = 1 << 1, /* Should existence of this property be mandatory? */
 256         JSON_LOG        = 1 << 2, /* Should the parser log about errors? */
 257         JSON_SAFE       = 1 << 3, /* Don't accept "unsafe" strings in json_dispatch_string() + json_dispatch_string() */
 258         JSON_RELAX      = 1 << 4, /* Use relaxed user name checking in json_dispatch_user_group_name */
 259
 260         /* The following two may be passed into log_json() in addition to the three above */
 261         JSON_DEBUG      = 1 << 4, /* Indicates that this log message is a debug message */
 262         JSON_WARNING    = 1 << 5, /* Indicates that this log message is a warning message */
 263 } JsonDispatchFlags;
 264
 265 typedef int (*JsonDispatchCallback)(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
 266
 267 typedef struct JsonDispatch {
 268         const char *name;
 269         JsonVariantType type;
 270         JsonDispatchCallback callback;
 271         size_t offset;
 272         JsonDispatchFlags flags;
 273 } JsonDispatch;
 274
 275 int json_dispatch(JsonVariant *v, const JsonDispatch table[], JsonDispatchCallback bad, JsonDispatchFlags flags, void *userdata);
 276
 277 int json_dispatch_string(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
 278 int json_dispatch_const_string(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
 279 int json_dispatch_strv(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
 280 int json_dispatch_boolean(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
 281 int json_dispatch_tristate(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
 282 int json_dispatch_variant(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
 283 int json_dispatch_integer(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
 284 int json_dispatch_unsigned(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
 285 int json_dispatch_uint32(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
 286 int json_dispatch_int32(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
 287 int json_dispatch_uid_gid(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
 288 int json_dispatch_user_group_name(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
 289 int json_dispatch_id128(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
 290 int json_dispatch_unsupported(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
 291
 292 assert_cc(sizeof(uintmax_t) == sizeof(uint64_t));
 293 #define json_dispatch_uint64 json_dispatch_unsigned
 294
 295 assert_cc(sizeof(intmax_t) == sizeof(int64_t));
 296 #define json_dispatch_int64 json_dispatch_integer
 297
 298 static inline int json_dispatch_level(JsonDispatchFlags flags) {
 299
 300         /* Did the user request no logging? If so, then never log higher than LOG_DEBUG. Also, if this is marked as
 301          * debug message, then also log at debug level. */
 302
 303         if (!(flags & JSON_LOG) ||
 304             (flags & JSON_DEBUG))
 305                 return LOG_DEBUG;
 306
 307         /* Are we invoked in permissive mode, or is this explicitly marked as warning message? Then this should be
 308          * printed at LOG_WARNING */
 309         if (flags & (JSON_PERMISSIVE|JSON_WARNING))
 310                 return LOG_WARNING;
 311
 312         /* Otherwise it's an error. */
 313         return LOG_ERR;
 314 }
 315
 316 int json_log_internal(JsonVariant *variant, int level, int error, const char *file, int line, const char *func, const char *format, ...)  _printf_(7, 8);
 317
 318 #define json_log(variant, flags, error, ...)                            \
 319         ({                                                              \
 320                 int _level = json_dispatch_level(flags), _e = (error);  \
 321                 (log_get_max_level() >= LOG_PRI(_level))                \
 322                         ? json_log_internal(variant, _level, _e, PROJECT_FILE, __LINE__, __func__, __VA_ARGS__) \
 323                         : -ERRNO_VALUE(_e);                             \
 324         })
 325
 326 #define json_log_oom(variant, flags) \
 327         json_log(variant, flags, SYNTHETIC_ERRNO(ENOMEM), "Out of memory.")
 328
 329 #define JSON_VARIANT_STRING_CONST(x) _JSON_VARIANT_STRING_CONST(UNIQ, (x))
 330
 331 #define _JSON_VARIANT_STRING_CONST(xq, x)                               \
 332         ({                                                              \
 333                 _align_(2) static const char UNIQ_T(json_string_const, xq)[] = (x); \
 334                 assert((((uintptr_t) UNIQ_T(json_string_const, xq)) & 1) == 0); \
 335                 (JsonVariant*) ((uintptr_t) UNIQ_T(json_string_const, xq) + 1); \
 336         })
 337
 338 int json_variant_unbase64(JsonVariant *v, void **ret, size_t *ret_size);
 339
 340 const char *json_variant_type_to_string(JsonVariantType t);
 341 JsonVariantType json_variant_type_from_string(const char *s);