src/shared/json.h

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   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 "sd-id128.h"
  11
  12 #include "macro.h"
  13 #include "string-util.h"
  14 #include "log.h"
  15
  16 /*
  17   In case you wonder why we have our own JSON implementation, here are a couple of reasons why this implementation has
  18   benefits over various other implementations:
  19
  20   - We need support for 64bit signed and unsigned integers, i.e. the full 64,5bit range of -9223372036854775808…18446744073709551615
  21   - All our variants are immutable after creation
  22   - Special values such as true, false, zero, null, empty strings, empty array, empty objects require zero dynamic memory
  23   - Progressive parsing
  24   - Our integer/real type implicitly converts, but only if that's safe and loss-lessly possible
  25   - There's a "builder" for putting together objects easily in varargs function calls
  26   - There's a "dispatcher" for mapping objects to C data structures
  27   - Every variant optionally carries parsing location information, which simplifies debugging and parse log error generation
  28   - Formatter has color, line, column support
  29
  30   Limitations:
  31   - Doesn't allow embedded NUL in strings
  32   - Can't store integers outside of the -9223372036854775808…18446744073709551615 range (it will use 'long double' for
  33     values outside this range, which is lossy)
  34   - Can't store negative zero (will be treated identical to positive zero, and not retained across serialization)
  35   - Can't store non-integer numbers that can't be stored in "long double" losslessly
  36   - Allows creation and parsing of objects with duplicate keys. The "dispatcher" will refuse them however. This means
  37     we can parse and pass around such objects, but will carefully refuse them when we convert them into our own data.
  38
  39   (These limitations should be pretty much in line with those of other JSON implementations, in fact might be less
  40   limiting in most cases even.)
  41 */
  42
  43 typedef struct JsonVariant JsonVariant;
  44
  45 typedef enum JsonVariantType {
  46         JSON_VARIANT_STRING,
  47         JSON_VARIANT_INTEGER,
  48         JSON_VARIANT_UNSIGNED,
  49         JSON_VARIANT_REAL,
  50         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 */
  51         JSON_VARIANT_BOOLEAN,
  52         JSON_VARIANT_ARRAY,
  53         JSON_VARIANT_OBJECT,
  54         JSON_VARIANT_NULL,
  55         _JSON_VARIANT_TYPE_MAX,
  56         _JSON_VARIANT_TYPE_INVALID = -EINVAL,
  57 } JsonVariantType;
  58
  59 int json_variant_new_stringn(JsonVariant **ret, const char *s, size_t n);
  60 int json_variant_new_base64(JsonVariant **ret, const void *p, size_t n);
  61 int json_variant_new_hex(JsonVariant **ret, const void *p, size_t n);
  62 int json_variant_new_integer(JsonVariant **ret, intmax_t i);
  63 int json_variant_new_unsigned(JsonVariant **ret, uintmax_t u);
  64 int json_variant_new_real(JsonVariant **ret, long double d);
  65 int json_variant_new_boolean(JsonVariant **ret, bool b);
  66 int json_variant_new_array(JsonVariant **ret, JsonVariant **array, size_t n);
  67 int json_variant_new_array_bytes(JsonVariant **ret, const void *p, size_t n);
  68 int json_variant_new_array_strv(JsonVariant **ret, char **l);
  69 int json_variant_new_object(JsonVariant **ret, JsonVariant **array, size_t n);
  70 int json_variant_new_null(JsonVariant **ret);
  71 int json_variant_new_id128(JsonVariant **ret, sd_id128_t id);
  72
  73 static inline int json_variant_new_string(JsonVariant **ret, const char *s) {
  74         return json_variant_new_stringn(ret, s, SIZE_MAX);
  75 }
  76
  77 JsonVariant *json_variant_ref(JsonVariant *v);
  78 JsonVariant *json_variant_unref(JsonVariant *v);
  79 void json_variant_unref_many(JsonVariant **array, size_t n);
  80
  81 DEFINE_TRIVIAL_CLEANUP_FUNC(JsonVariant *, json_variant_unref);
  82
  83 const char *json_variant_string(JsonVariant *v);
  84 intmax_t json_variant_integer(JsonVariant *v);
  85 uintmax_t json_variant_unsigned(JsonVariant *v);
  86 long double json_variant_real(JsonVariant *v);
  87 bool json_variant_boolean(JsonVariant *v);
  88
  89 JsonVariantType json_variant_type(JsonVariant *v);
  90 bool json_variant_has_type(JsonVariant *v, JsonVariantType type);
  91
  92 static inline bool json_variant_is_string(JsonVariant *v) {
  93         return json_variant_has_type(v, JSON_VARIANT_STRING);
  94 }
  95
  96 static inline bool json_variant_is_integer(JsonVariant *v) {
  97         return json_variant_has_type(v, JSON_VARIANT_INTEGER);
  98 }
  99
 100 static inline bool json_variant_is_unsigned(JsonVariant *v) {
 101         return json_variant_has_type(v, JSON_VARIANT_UNSIGNED);
 102 }
 103
 104 static inline bool json_variant_is_real(JsonVariant *v) {
 105         return json_variant_has_type(v, JSON_VARIANT_REAL);
 106 }
 107
 108 static inline bool json_variant_is_number(JsonVariant *v) {
 109         return json_variant_has_type(v, JSON_VARIANT_NUMBER);
 110 }
 111
 112 static inline bool json_variant_is_boolean(JsonVariant *v) {
 113         return json_variant_has_type(v, JSON_VARIANT_BOOLEAN);
 114 }
 115
 116 static inline bool json_variant_is_array(JsonVariant *v) {
 117         return json_variant_has_type(v, JSON_VARIANT_ARRAY);
 118 }
 119
 120 static inline bool json_variant_is_object(JsonVariant *v) {
 121         return json_variant_has_type(v, JSON_VARIANT_OBJECT);
 122 }
 123
 124 static inline bool json_variant_is_null(JsonVariant *v) {
 125         return json_variant_has_type(v, JSON_VARIANT_NULL);
 126 }
 127
 128 bool json_variant_is_negative(JsonVariant *v);
 129 bool json_variant_is_blank_object(JsonVariant *v);
 130 bool json_variant_is_blank_array(JsonVariant *v);
 131 bool json_variant_is_normalized(JsonVariant *v);
 132 bool json_variant_is_sorted(JsonVariant *v);
 133
 134 size_t json_variant_elements(JsonVariant *v);
 135 JsonVariant *json_variant_by_index(JsonVariant *v, size_t index);
 136 JsonVariant *json_variant_by_key(JsonVariant *v, const char *key);
 137 JsonVariant *json_variant_by_key_full(JsonVariant *v, const char *key, JsonVariant **ret_key);
 138
 139 bool json_variant_equal(JsonVariant *a, JsonVariant *b);
 140
 141 void json_variant_sensitive(JsonVariant *v);
 142 bool json_variant_is_sensitive(JsonVariant *v);
 143
 144 struct json_variant_foreach_state {
 145         JsonVariant *variant;
 146         size_t idx;
 147 };
 148
 149 #define JSON_VARIANT_ARRAY_FOREACH(i, v)                                \
 150         for (struct json_variant_foreach_state _state = { (v), 0 };     \
 151              json_variant_is_array(_state.variant) &&                   \
 152                      _state.idx < json_variant_elements(_state.variant) && \
 153                      ({ i = json_variant_by_index(_state.variant, _state.idx); \
 154                              true; });                                  \
 155              _state.idx++)
 156
 157 #define JSON_VARIANT_OBJECT_FOREACH(k, e, v)                            \
 158         for (struct json_variant_foreach_state _state = { (v), 0 };     \
 159              json_variant_is_object(_state.variant) &&                  \
 160                      _state.idx < json_variant_elements(_state.variant) && \
 161                      ({ k = json_variant_string(json_variant_by_index(_state.variant, _state.idx)); \
 162                              e = json_variant_by_index(_state.variant, _state.idx + 1); \
 163                              true; });                                  \
 164              _state.idx += 2)
 165
 166 int json_variant_get_source(JsonVariant *v, const char **ret_source, unsigned *ret_line, unsigned *ret_column);
 167
 168 typedef enum JsonFormatFlags {
 169         JSON_FORMAT_NEWLINE     = 1 << 0, /* suffix with newline */
 170         JSON_FORMAT_PRETTY      = 1 << 1, /* add internal whitespace to appeal to human readers */
 171         JSON_FORMAT_PRETTY_AUTO = 1 << 2, /* same, but only if connected to a tty (and JSON_FORMAT_NEWLINE otherwise) */
 172         JSON_FORMAT_COLOR       = 1 << 3, /* insert ANSI color sequences */
 173         JSON_FORMAT_COLOR_AUTO  = 1 << 4, /* insert ANSI color sequences if colors_enabled() says so */
 174         JSON_FORMAT_SOURCE      = 1 << 5, /* prefix with source filename/line/column */
 175         JSON_FORMAT_SSE         = 1 << 6, /* prefix/suffix with W3C server-sent events */
 176         JSON_FORMAT_SEQ         = 1 << 7, /* prefix/suffix with RFC 7464 application/json-seq */
 177         JSON_FORMAT_FLUSH       = 1 << 8, /* call fflush() after dumping JSON */
 178         JSON_FORMAT_OFF         = 1 << 9, /* make json_variant_format() fail with -ENOEXEC */
 179 } JsonFormatFlags;
 180
 181 int json_variant_format(JsonVariant *v, JsonFormatFlags flags, char **ret);
 182 void json_variant_dump(JsonVariant *v, JsonFormatFlags flags, FILE *f, const char *prefix);
 183
 184 int json_variant_filter(JsonVariant **v, char **to_remove);
 185
 186 int json_variant_set_field(JsonVariant **v, const char *field, JsonVariant *value);
 187 int json_variant_set_field_string(JsonVariant **v, const char *field, const char *value);
 188 int json_variant_set_field_integer(JsonVariant **v, const char *field, intmax_t value);
 189 int json_variant_set_field_unsigned(JsonVariant **v, const char *field, uintmax_t value);
 190 int json_variant_set_field_boolean(JsonVariant **v, const char *field, bool b);
 191 int json_variant_set_field_strv(JsonVariant **v, const char *field, char **l);
 192
 193 int json_variant_append_array(JsonVariant **v, JsonVariant *element);
 194
 195 int json_variant_merge(JsonVariant **v, JsonVariant *m);
 196
 197 int json_variant_strv(JsonVariant *v, char ***ret);
 198
 199 int json_variant_sort(JsonVariant **v);
 200 int json_variant_normalize(JsonVariant **v);
 201
 202 typedef enum JsonParseFlags {
 203         JSON_PARSE_SENSITIVE = 1 << 0, /* mark variant as "sensitive", i.e. something containing secret key material or such */
 204 } JsonParseFlags;
 205
 206 int json_parse(const char *string, JsonParseFlags flags, JsonVariant **ret, unsigned *ret_line, unsigned *ret_column);
 207 int json_parse_continue(const char **p, JsonParseFlags flags, JsonVariant **ret, unsigned *ret_line, unsigned *ret_column);
 208 int json_parse_file_at(FILE *f, int dir_fd, const char *path, JsonParseFlags flags, JsonVariant **ret, unsigned *ret_line, unsigned *ret_column);
 209
 210 static inline int json_parse_file(FILE *f, const char *path, JsonParseFlags flags, JsonVariant **ret, unsigned *ret_line, unsigned *ret_column) {
 211         return json_parse_file_at(f, AT_FDCWD, path, flags, ret, ret_line, ret_column);
 212 }
 213
 214 enum {
 215         _JSON_BUILD_STRING,
 216         _JSON_BUILD_INTEGER,
 217         _JSON_BUILD_UNSIGNED,
 218         _JSON_BUILD_REAL,
 219         _JSON_BUILD_BOOLEAN,
 220         _JSON_BUILD_ARRAY_BEGIN,
 221         _JSON_BUILD_ARRAY_END,
 222         _JSON_BUILD_OBJECT_BEGIN,
 223         _JSON_BUILD_OBJECT_END,
 224         _JSON_BUILD_PAIR,
 225         _JSON_BUILD_PAIR_CONDITION,
 226         _JSON_BUILD_NULL,
 227         _JSON_BUILD_VARIANT,
 228         _JSON_BUILD_VARIANT_ARRAY,
 229         _JSON_BUILD_LITERAL,
 230         _JSON_BUILD_STRV,
 231         _JSON_BUILD_BASE64,
 232         _JSON_BUILD_HEX,
 233         _JSON_BUILD_ID128,
 234         _JSON_BUILD_BYTE_ARRAY,
 235         _JSON_BUILD_MAX,
 236 };
 237
 238 #define JSON_BUILD_STRING(s) _JSON_BUILD_STRING, ({ const char *_x = s; _x; })
 239 #define JSON_BUILD_INTEGER(i) _JSON_BUILD_INTEGER, ({ intmax_t _x = i; _x; })
 240 #define JSON_BUILD_UNSIGNED(u) _JSON_BUILD_UNSIGNED, ({ uintmax_t _x = u; _x; })
 241 #define JSON_BUILD_REAL(d) _JSON_BUILD_REAL, ({ long double _x = d; _x; })
 242 #define JSON_BUILD_BOOLEAN(b) _JSON_BUILD_BOOLEAN, ({ bool _x = b; _x; })
 243 #define JSON_BUILD_ARRAY(...) _JSON_BUILD_ARRAY_BEGIN, __VA_ARGS__, _JSON_BUILD_ARRAY_END
 244 #define JSON_BUILD_EMPTY_ARRAY _JSON_BUILD_ARRAY_BEGIN, _JSON_BUILD_ARRAY_END
 245 #define JSON_BUILD_OBJECT(...) _JSON_BUILD_OBJECT_BEGIN, __VA_ARGS__, _JSON_BUILD_OBJECT_END
 246 #define JSON_BUILD_EMPTY_OBJECT _JSON_BUILD_OBJECT_BEGIN, _JSON_BUILD_OBJECT_END
 247 #define JSON_BUILD_PAIR(n, ...) _JSON_BUILD_PAIR, ({ const char *_x = n; _x; }), __VA_ARGS__
 248 #define JSON_BUILD_PAIR_CONDITION(c, n, ...) _JSON_BUILD_PAIR_CONDITION, ({ bool _x = c; _x; }), ({ const char *_x = n; _x; }), __VA_ARGS__
 249 #define JSON_BUILD_NULL _JSON_BUILD_NULL
 250 #define JSON_BUILD_VARIANT(v) _JSON_BUILD_VARIANT, ({ JsonVariant *_x = v; _x; })
 251 #define JSON_BUILD_VARIANT_ARRAY(v, n) _JSON_BUILD_VARIANT_ARRAY, ({ JsonVariant **_x = v; _x; }), ({ size_t _y = n; _y; })
 252 #define JSON_BUILD_LITERAL(l) _JSON_BUILD_LITERAL, ({ const char *_x = l; _x; })
 253 #define JSON_BUILD_STRV(l) _JSON_BUILD_STRV, ({ char **_x = l; _x; })
 254 #define JSON_BUILD_BASE64(p, n) _JSON_BUILD_BASE64, ({ const void *_x = p; _x; }), ({ size_t _y = n; _y; })
 255 #define JSON_BUILD_HEX(p, n) _JSON_BUILD_HEX, ({ const void *_x = p; _x; }), ({ size_t _y = n; _y; })
 256 #define JSON_BUILD_ID128(id) _JSON_BUILD_ID128, ({ sd_id128_t _x = id; _x; })
 257 #define JSON_BUILD_BYTE_ARRAY(v, n) _JSON_BUILD_BYTE_ARRAY, ({ const void *_x = v; _x; }), ({ size_t _y = n; _y; })
 258
 259 int json_build(JsonVariant **ret, ...);
 260 int json_buildv(JsonVariant **ret, va_list ap);
 261
 262 /* A bitmask of flags used by the dispatch logic. Note that this is a combined bit mask, that is generated from the bit
 263  * mask originally passed into json_dispatch(), the individual bitmask associated with the static JsonDispatch callout
 264  * entry, as well the bitmask specified for json_log() calls */
 265 typedef enum JsonDispatchFlags {
 266         /* The following three may be set in JsonDispatch's .flags field or the json_dispatch() flags parameter  */
 267         JSON_PERMISSIVE = 1 << 0, /* Shall parsing errors be considered fatal for this property? */
 268         JSON_MANDATORY  = 1 << 1, /* Should existence of this property be mandatory? */
 269         JSON_LOG        = 1 << 2, /* Should the parser log about errors? */
 270         JSON_SAFE       = 1 << 3, /* Don't accept "unsafe" strings in json_dispatch_string() + json_dispatch_string() */
 271         JSON_RELAX      = 1 << 4, /* Use relaxed user name checking in json_dispatch_user_group_name */
 272
 273         /* The following two may be passed into log_json() in addition to the three above */
 274         JSON_DEBUG      = 1 << 4, /* Indicates that this log message is a debug message */
 275         JSON_WARNING    = 1 << 5, /* Indicates that this log message is a warning message */
 276 } JsonDispatchFlags;
 277
 278 typedef int (*JsonDispatchCallback)(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
 279
 280 typedef struct JsonDispatch {
 281         const char *name;
 282         JsonVariantType type;
 283         JsonDispatchCallback callback;
 284         size_t offset;
 285         JsonDispatchFlags flags;
 286 } JsonDispatch;
 287
 288 int json_dispatch(JsonVariant *v, const JsonDispatch table[], JsonDispatchCallback bad, JsonDispatchFlags flags, void *userdata);
 289
 290 int json_dispatch_string(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
 291 int json_dispatch_const_string(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
 292 int json_dispatch_strv(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
 293 int json_dispatch_boolean(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
 294 int json_dispatch_tristate(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
 295 int json_dispatch_variant(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
 296 int json_dispatch_intmax(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
 297 int json_dispatch_uintmax(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
 298 int json_dispatch_uint32(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
 299 int json_dispatch_int32(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
 300 int json_dispatch_uid_gid(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
 301 int json_dispatch_user_group_name(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
 302 int json_dispatch_id128(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
 303 int json_dispatch_unsupported(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
 304
 305 assert_cc(sizeof(uintmax_t) == sizeof(uint64_t));
 306 #define json_dispatch_uint64 json_dispatch_uintmax
 307
 308 assert_cc(sizeof(intmax_t) == sizeof(int64_t));
 309 #define json_dispatch_int64 json_dispatch_intmax
 310
 311 assert_cc(sizeof(uint32_t) == sizeof(unsigned));
 312 #define json_dispatch_uint json_dispatch_uint32
 313
 314 assert_cc(sizeof(int32_t) == sizeof(int));
 315 #define json_dispatch_int json_dispatch_int32
 316
 317 static inline int json_dispatch_level(JsonDispatchFlags flags) {
 318
 319         /* Did the user request no logging? If so, then never log higher than LOG_DEBUG. Also, if this is marked as
 320          * debug message, then also log at debug level. */
 321
 322         if (!(flags & JSON_LOG) ||
 323             (flags & JSON_DEBUG))
 324                 return LOG_DEBUG;
 325
 326         /* Are we invoked in permissive mode, or is this explicitly marked as warning message? Then this should be
 327          * printed at LOG_WARNING */
 328         if (flags & (JSON_PERMISSIVE|JSON_WARNING))
 329                 return LOG_WARNING;
 330
 331         /* Otherwise it's an error. */
 332         return LOG_ERR;
 333 }
 334
 335 int json_log_internal(JsonVariant *variant, int level, int error, const char *file, int line, const char *func, const char *format, ...)  _printf_(7, 8);
 336
 337 #define json_log(variant, flags, error, ...)                            \
 338         ({                                                              \
 339                 int _level = json_dispatch_level(flags), _e = (error);  \
 340                 (log_get_max_level() >= LOG_PRI(_level))                \
 341                         ? json_log_internal(variant, _level, _e, PROJECT_FILE, __LINE__, __func__, __VA_ARGS__) \
 342                         : -ERRNO_VALUE(_e);                             \
 343         })
 344
 345 #define json_log_oom(variant, flags) \
 346         json_log(variant, flags, SYNTHETIC_ERRNO(ENOMEM), "Out of memory.")
 347
 348 #define JSON_VARIANT_STRING_CONST(x) _JSON_VARIANT_STRING_CONST(UNIQ, (x))
 349
 350 #define _JSON_VARIANT_STRING_CONST(xq, x)                               \
 351         ({                                                              \
 352                 _align_(2) static const char UNIQ_T(json_string_const, xq)[] = (x); \
 353                 assert((((uintptr_t) UNIQ_T(json_string_const, xq)) & 1) == 0); \
 354                 (JsonVariant*) ((uintptr_t) UNIQ_T(json_string_const, xq) + 1); \
 355         })
 356
 357 int json_variant_unbase64(JsonVariant *v, void **ret, size_t *ret_size);
 358 int json_variant_unhex(JsonVariant *v, void **ret, size_t *ret_size);
 359
 360 const char *json_variant_type_to_string(JsonVariantType t);
 361 JsonVariantType json_variant_type_from_string(const char *s);