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diff --git a/src/shared/json.h b/src/shared/json.h
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+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+
+#include "sd-id128.h"
+
+#include "macro.h"
+#include "string-util.h"
+#include "log.h"
+
+/*
+ In case you wonder why we have our own JSON implementation, here are a couple of reasons why this implementation has
+ benefits over various other implementations:
+
+ - We need support for 64bit signed and unsigned integers, i.e. the full 64,5bit range of -9223372036854775808…18446744073709551615
+ - All our variants are immutable after creation
+ - Special values such as true, false, zero, null, empty strings, empty array, empty objects require zero dynamic memory
+ - Progressive parsing
+ - Our integer/real type implicitly converts, but only if that's safe and loss-lessly possible
+ - There's a "builder" for putting together objects easily in varargs function calls
+ - There's a "dispatcher" for mapping objects to C data structures
+ - Every variant optionally carries parsing location information, which simplifies debugging and parse log error generation
+ - Formatter has color, line, column support
+
+ Limitations:
+ - Doesn't allow embedded NUL in strings
+ - Can't store integers outside of the -9223372036854775808…18446744073709551615 range (it will use 'long double' for
+ values outside this range, which is lossy)
+ - Can't store negative zero (will be treated identical to positive zero, and not retained across serialization)
+ - Can't store non-integer numbers that can't be stored in "long double" losslessly
+ - Allows creation and parsing of objects with duplicate keys. The "dispatcher" will refuse them however. This means
+ we can parse and pass around such objects, but will carefully refuse them when we convert them into our own data.
+
+ (These limitations should be pretty much in line with those of other JSON implementations, in fact might be less
+ limiting in most cases even.)
+*/
+
+typedef struct JsonVariant JsonVariant;
+
+typedef enum JsonVariantType {
+ JSON_VARIANT_STRING,
+ JSON_VARIANT_INTEGER,
+ JSON_VARIANT_UNSIGNED,
+ JSON_VARIANT_REAL,
+ 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 */
+ JSON_VARIANT_BOOLEAN,
+ JSON_VARIANT_ARRAY,
+ JSON_VARIANT_OBJECT,
+ JSON_VARIANT_NULL,
+ _JSON_VARIANT_TYPE_MAX,
+ _JSON_VARIANT_TYPE_INVALID = -1
+} JsonVariantType;
+
+int json_variant_new_stringn(JsonVariant **ret, const char *s, size_t n);
+int json_variant_new_base64(JsonVariant **ret, const void *p, size_t n);
+int json_variant_new_integer(JsonVariant **ret, intmax_t i);
+int json_variant_new_unsigned(JsonVariant **ret, uintmax_t u);
+int json_variant_new_real(JsonVariant **ret, long double d);
+int json_variant_new_boolean(JsonVariant **ret, bool b);
+int json_variant_new_array(JsonVariant **ret, JsonVariant **array, size_t n);
+int json_variant_new_array_bytes(JsonVariant **ret, const void *p, size_t n);
+int json_variant_new_array_strv(JsonVariant **ret, char **l);
+int json_variant_new_object(JsonVariant **ret, JsonVariant **array, size_t n);
+int json_variant_new_null(JsonVariant **ret);
+int json_variant_new_id128(JsonVariant **ret, sd_id128_t id);
+
+static inline int json_variant_new_string(JsonVariant **ret, const char *s) {
+ return json_variant_new_stringn(ret, s, (size_t) -1);
+}
+
+JsonVariant *json_variant_ref(JsonVariant *v);
+JsonVariant *json_variant_unref(JsonVariant *v);
+void json_variant_unref_many(JsonVariant **array, size_t n);
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(JsonVariant *, json_variant_unref);
+
+const char *json_variant_string(JsonVariant *v);
+intmax_t json_variant_integer(JsonVariant *v);
+uintmax_t json_variant_unsigned(JsonVariant *v);
+long double json_variant_real(JsonVariant *v);
+bool json_variant_boolean(JsonVariant *v);
+
+JsonVariantType json_variant_type(JsonVariant *v);
+bool json_variant_has_type(JsonVariant *v, JsonVariantType type);
+
+static inline bool json_variant_is_string(JsonVariant *v) {
+ return json_variant_has_type(v, JSON_VARIANT_STRING);
+}
+
+static inline bool json_variant_is_integer(JsonVariant *v) {
+ return json_variant_has_type(v, JSON_VARIANT_INTEGER);
+}
+
+static inline bool json_variant_is_unsigned(JsonVariant *v) {
+ return json_variant_has_type(v, JSON_VARIANT_UNSIGNED);
+}
+
+static inline bool json_variant_is_real(JsonVariant *v) {
+ return json_variant_has_type(v, JSON_VARIANT_REAL);
+}
+
+static inline bool json_variant_is_number(JsonVariant *v) {
+ return json_variant_has_type(v, JSON_VARIANT_NUMBER);
+}
+
+static inline bool json_variant_is_boolean(JsonVariant *v) {
+ return json_variant_has_type(v, JSON_VARIANT_BOOLEAN);
+}
+
+static inline bool json_variant_is_array(JsonVariant *v) {
+ return json_variant_has_type(v, JSON_VARIANT_ARRAY);
+}
+
+static inline bool json_variant_is_object(JsonVariant *v) {
+ return json_variant_has_type(v, JSON_VARIANT_OBJECT);
+}
+
+static inline bool json_variant_is_null(JsonVariant *v) {
+ return json_variant_has_type(v, JSON_VARIANT_NULL);
+}
+
+bool json_variant_is_negative(JsonVariant *v);
+bool json_variant_is_blank_object(JsonVariant *v);
+bool json_variant_is_blank_array(JsonVariant *v);
+bool json_variant_is_normalized(JsonVariant *v);
+bool json_variant_is_sorted(JsonVariant *v);
+
+size_t json_variant_elements(JsonVariant *v);
+JsonVariant *json_variant_by_index(JsonVariant *v, size_t index);
+JsonVariant *json_variant_by_key(JsonVariant *v, const char *key);
+JsonVariant *json_variant_by_key_full(JsonVariant *v, const char *key, JsonVariant **ret_key);
+
+bool json_variant_equal(JsonVariant *a, JsonVariant *b);
+
+void json_variant_sensitive(JsonVariant *v);
+bool json_variant_is_sensitive(JsonVariant *v);
+
+struct json_variant_foreach_state {
+ JsonVariant *variant;
+ size_t idx;
+};
+
+#define JSON_VARIANT_ARRAY_FOREACH(i, v) \
+ for (struct json_variant_foreach_state _state = { (v), 0 }; \
+ json_variant_is_array(_state.variant) && \
+ _state.idx < json_variant_elements(_state.variant) && \
+ ({ i = json_variant_by_index(_state.variant, _state.idx); \
+ true; }); \
+ _state.idx++)
+
+#define JSON_VARIANT_OBJECT_FOREACH(k, e, v) \
+ for (struct json_variant_foreach_state _state = { (v), 0 }; \
+ json_variant_is_object(_state.variant) && \
+ _state.idx < json_variant_elements(_state.variant) && \
+ ({ k = json_variant_string(json_variant_by_index(_state.variant, _state.idx)); \
+ e = json_variant_by_index(_state.variant, _state.idx + 1); \
+ true; }); \
+ _state.idx += 2)
+
+int json_variant_get_source(JsonVariant *v, const char **ret_source, unsigned *ret_line, unsigned *ret_column);
+
+typedef enum JsonFormatFlags {
+ JSON_FORMAT_NEWLINE = 1 << 0, /* suffix with newline */
+ JSON_FORMAT_PRETTY = 1 << 1, /* add internal whitespace to appeal to human readers */
+ JSON_FORMAT_PRETTY_AUTO = 1 << 2, /* same, but only if connected to a tty (and JSON_FORMAT_NEWLINE otherwise) */
+ JSON_FORMAT_COLOR = 1 << 3, /* insert ANSI color sequences */
+ JSON_FORMAT_COLOR_AUTO = 1 << 4, /* insert ANSI color sequences if colors_enabled() says so */
+ JSON_FORMAT_SOURCE = 1 << 5, /* prefix with source filename/line/column */
+ JSON_FORMAT_SSE = 1 << 6, /* prefix/suffix with W3C server-sent events */
+ JSON_FORMAT_SEQ = 1 << 7, /* prefix/suffix with RFC 7464 application/json-seq */
+ JSON_FORMAT_FLUSH = 1 << 8, /* call fflush() after dumping JSON */
+} JsonFormatFlags;
+
+int json_variant_format(JsonVariant *v, JsonFormatFlags flags, char **ret);
+void json_variant_dump(JsonVariant *v, JsonFormatFlags flags, FILE *f, const char *prefix);
+
+int json_variant_filter(JsonVariant **v, char **to_remove);
+
+int json_variant_set_field(JsonVariant **v, const char *field, JsonVariant *value);
+int json_variant_set_field_string(JsonVariant **v, const char *field, const char *value);
+int json_variant_set_field_integer(JsonVariant **v, const char *field, intmax_t value);
+int json_variant_set_field_unsigned(JsonVariant **v, const char *field, uintmax_t value);
+int json_variant_set_field_boolean(JsonVariant **v, const char *field, bool b);
+int json_variant_set_field_strv(JsonVariant **v, const char *field, char **l);
+
+int json_variant_append_array(JsonVariant **v, JsonVariant *element);
+
+int json_variant_merge(JsonVariant **v, JsonVariant *m);
+
+int json_variant_strv(JsonVariant *v, char ***ret);
+
+int json_variant_sort(JsonVariant **v);
+int json_variant_normalize(JsonVariant **v);
+
+typedef enum JsonParseFlags {
+ JSON_PARSE_SENSITIVE = 1 << 0, /* mark variant as "sensitive", i.e. something containing secret key material or such */
+} JsonParseFlags;
+
+int json_parse(const char *string, JsonParseFlags flags, JsonVariant **ret, unsigned *ret_line, unsigned *ret_column);
+int json_parse_continue(const char **p, JsonParseFlags flags, JsonVariant **ret, unsigned *ret_line, unsigned *ret_column);
+int json_parse_file_at(FILE *f, int dir_fd, const char *path, JsonParseFlags flags, JsonVariant **ret, unsigned *ret_line, unsigned *ret_column);
+
+static inline int json_parse_file(FILE *f, const char *path, JsonParseFlags flags, JsonVariant **ret, unsigned *ret_line, unsigned *ret_column) {
+ return json_parse_file_at(f, AT_FDCWD, path, flags, ret, ret_line, ret_column);
+}
+
+enum {
+ _JSON_BUILD_STRING,
+ _JSON_BUILD_INTEGER,
+ _JSON_BUILD_UNSIGNED,
+ _JSON_BUILD_REAL,
+ _JSON_BUILD_BOOLEAN,
+ _JSON_BUILD_ARRAY_BEGIN,
+ _JSON_BUILD_ARRAY_END,
+ _JSON_BUILD_OBJECT_BEGIN,
+ _JSON_BUILD_OBJECT_END,
+ _JSON_BUILD_PAIR,
+ _JSON_BUILD_PAIR_CONDITION,
+ _JSON_BUILD_NULL,
+ _JSON_BUILD_VARIANT,
+ _JSON_BUILD_VARIANT_ARRAY,
+ _JSON_BUILD_LITERAL,
+ _JSON_BUILD_STRV,
+ _JSON_BUILD_BASE64,
+ _JSON_BUILD_ID128,
+ _JSON_BUILD_BYTE_ARRAY,
+ _JSON_BUILD_MAX,
+};
+
+#define JSON_BUILD_STRING(s) _JSON_BUILD_STRING, ({ const char *_x = s; _x; })
+#define JSON_BUILD_INTEGER(i) _JSON_BUILD_INTEGER, ({ intmax_t _x = i; _x; })
+#define JSON_BUILD_UNSIGNED(u) _JSON_BUILD_UNSIGNED, ({ uintmax_t _x = u; _x; })
+#define JSON_BUILD_REAL(d) _JSON_BUILD_REAL, ({ long double _x = d; _x; })
+#define JSON_BUILD_BOOLEAN(b) _JSON_BUILD_BOOLEAN, ({ bool _x = b; _x; })
+#define JSON_BUILD_ARRAY(...) _JSON_BUILD_ARRAY_BEGIN, __VA_ARGS__, _JSON_BUILD_ARRAY_END
+#define JSON_BUILD_EMPTY_ARRAY _JSON_BUILD_ARRAY_BEGIN, _JSON_BUILD_ARRAY_END
+#define JSON_BUILD_OBJECT(...) _JSON_BUILD_OBJECT_BEGIN, __VA_ARGS__, _JSON_BUILD_OBJECT_END
+#define JSON_BUILD_EMPTY_OBJECT _JSON_BUILD_OBJECT_BEGIN, _JSON_BUILD_OBJECT_END
+#define JSON_BUILD_PAIR(n, ...) _JSON_BUILD_PAIR, ({ const char *_x = n; _x; }), __VA_ARGS__
+#define JSON_BUILD_PAIR_CONDITION(c, n, ...) _JSON_BUILD_PAIR_CONDITION, ({ bool _x = c; _x; }), ({ const char *_x = n; _x; }), __VA_ARGS__
+#define JSON_BUILD_NULL _JSON_BUILD_NULL
+#define JSON_BUILD_VARIANT(v) _JSON_BUILD_VARIANT, ({ JsonVariant *_x = v; _x; })
+#define JSON_BUILD_VARIANT_ARRAY(v, n) _JSON_BUILD_VARIANT_ARRAY, ({ JsonVariant **_x = v; _x; }), ({ size_t _y = n; _y; })
+#define JSON_BUILD_LITERAL(l) _JSON_BUILD_LITERAL, ({ const char *_x = l; _x; })
+#define JSON_BUILD_STRV(l) _JSON_BUILD_STRV, ({ char **_x = l; _x; })
+#define JSON_BUILD_BASE64(p, n) _JSON_BUILD_BASE64, ({ const void *_x = p; _x; }), ({ size_t _y = n; _y; })
+#define JSON_BUILD_ID128(id) _JSON_BUILD_ID128, ({ sd_id128_t _x = id; _x; })
+#define JSON_BUILD_BYTE_ARRAY(v, n) _JSON_BUILD_BYTE_ARRAY, ({ const void *_x = v; _x; }), ({ size_t _y = n; _y; })
+
+int json_build(JsonVariant **ret, ...);
+int json_buildv(JsonVariant **ret, va_list ap);
+
+/* A bitmask of flags used by the dispatch logic. Note that this is a combined bit mask, that is generated from the bit
+ * mask originally passed into json_dispatch(), the individual bitmask associated with the static JsonDispatch callout
+ * entry, as well the bitmask specified for json_log() calls */
+typedef enum JsonDispatchFlags {
+ /* The following three may be set in JsonDispatch's .flags field or the json_dispatch() flags parameter */
+ JSON_PERMISSIVE = 1 << 0, /* Shall parsing errors be considered fatal for this property? */
+ JSON_MANDATORY = 1 << 1, /* Should existence of this property be mandatory? */
+ JSON_LOG = 1 << 2, /* Should the parser log about errors? */
+ JSON_SAFE = 1 << 3, /* Don't accept "unsafe" strings in json_dispatch_string() + json_dispatch_string() */
+ JSON_RELAX = 1 << 4, /* Use relaxed user name checking in json_dispatch_user_group_name */
+
+ /* The following two may be passed into log_json() in addition to the three above */
+ JSON_DEBUG = 1 << 4, /* Indicates that this log message is a debug message */
+ JSON_WARNING = 1 << 5, /* Indicates that this log message is a warning message */
+} JsonDispatchFlags;
+
+typedef int (*JsonDispatchCallback)(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
+
+typedef struct JsonDispatch {
+ const char *name;
+ JsonVariantType type;
+ JsonDispatchCallback callback;
+ size_t offset;
+ JsonDispatchFlags flags;
+} JsonDispatch;
+
+int json_dispatch(JsonVariant *v, const JsonDispatch table[], JsonDispatchCallback bad, JsonDispatchFlags flags, void *userdata);
+
+int json_dispatch_string(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
+int json_dispatch_const_string(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
+int json_dispatch_strv(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
+int json_dispatch_boolean(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
+int json_dispatch_tristate(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
+int json_dispatch_variant(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
+int json_dispatch_integer(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
+int json_dispatch_unsigned(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
+int json_dispatch_uint32(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
+int json_dispatch_int32(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
+int json_dispatch_uid_gid(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
+int json_dispatch_user_group_name(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
+int json_dispatch_id128(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
+int json_dispatch_unsupported(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata);
+
+assert_cc(sizeof(uintmax_t) == sizeof(uint64_t));
+#define json_dispatch_uint64 json_dispatch_unsigned
+
+assert_cc(sizeof(intmax_t) == sizeof(int64_t));
+#define json_dispatch_int64 json_dispatch_integer
+
+assert_cc(sizeof(uint32_t) == sizeof(unsigned));
+#define json_dispatch_uint json_dispatch_uint32
+
+assert_cc(sizeof(int32_t) == sizeof(int));
+#define json_dispatch_int json_dispatch_int32
+
+static inline int json_dispatch_level(JsonDispatchFlags flags) {
+
+ /* Did the user request no logging? If so, then never log higher than LOG_DEBUG. Also, if this is marked as
+ * debug message, then also log at debug level. */
+
+ if (!(flags & JSON_LOG) ||
+ (flags & JSON_DEBUG))
+ return LOG_DEBUG;
+
+ /* Are we invoked in permissive mode, or is this explicitly marked as warning message? Then this should be
+ * printed at LOG_WARNING */
+ if (flags & (JSON_PERMISSIVE|JSON_WARNING))
+ return LOG_WARNING;
+
+ /* Otherwise it's an error. */
+ return LOG_ERR;
+}
+
+int json_log_internal(JsonVariant *variant, int level, int error, const char *file, int line, const char *func, const char *format, ...) _printf_(7, 8);
+
+#define json_log(variant, flags, error, ...) \
+ ({ \
+ int _level = json_dispatch_level(flags), _e = (error); \
+ (log_get_max_level() >= LOG_PRI(_level)) \
+ ? json_log_internal(variant, _level, _e, PROJECT_FILE, __LINE__, __func__, __VA_ARGS__) \
+ : -ERRNO_VALUE(_e); \
+ })
+
+#define json_log_oom(variant, flags) \
+ json_log(variant, flags, SYNTHETIC_ERRNO(ENOMEM), "Out of memory.")
+
+#define JSON_VARIANT_STRING_CONST(x) _JSON_VARIANT_STRING_CONST(UNIQ, (x))
+
+#define _JSON_VARIANT_STRING_CONST(xq, x) \
+ ({ \
+ _align_(2) static const char UNIQ_T(json_string_const, xq)[] = (x); \
+ assert((((uintptr_t) UNIQ_T(json_string_const, xq)) & 1) == 0); \
+ (JsonVariant*) ((uintptr_t) UNIQ_T(json_string_const, xq) + 1); \
+ })
+
+int json_variant_unbase64(JsonVariant *v, void **ret, size_t *ret_size);
+
+const char *json_variant_type_to_string(JsonVariantType t);
+JsonVariantType json_variant_type_from_string(const char *s);