8:36 a.m.
---
shared/jsmn.h | 471 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 471 insertions(+)
create mode 100644 shared/jsmn.h
diff --git a/shared/jsmn.h b/shared/jsmn.h
new file mode 100644
index 00000000..8ac14c1b
--- /dev/null
+++ b/shared/jsmn.h
@@ -0,0 +1,471 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2010 Serge Zaitsev
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#ifndef JSMN_H
+#define JSMN_H
+
+#include <stddef.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifdef JSMN_STATIC
+#define JSMN_API static
+#else
+#define JSMN_API extern
+#endif
+
+/**
+ * JSON type identifier. Basic types are:
+ * o Object
+ * o Array
+ * o String
+ * o Other primitive: number, boolean (true/false) or null
+ */
+typedef enum {
+ JSMN_UNDEFINED = 0,
+ JSMN_OBJECT = 1 << 0,
+ JSMN_ARRAY = 1 << 1,
+ JSMN_STRING = 1 << 2,
+ JSMN_PRIMITIVE = 1 << 3
+} jsmntype_t;
+
+enum jsmnerr {
+ /* Not enough tokens were provided */
+ JSMN_ERROR_NOMEM = -1,
+ /* Invalid character inside JSON string */
+ JSMN_ERROR_INVAL = -2,
+ /* The string is not a full JSON packet, more bytes expected */
+ JSMN_ERROR_PART = -3
+};
+
+/**
+ * JSON token description.
+ * type type (object, array, string etc.)
+ * start start position in JSON data string
+ * end end position in JSON data string
+ */
+typedef struct jsmntok {
+ jsmntype_t type;
+ int start;
+ int end;
+ int size;
+#ifdef JSMN_PARENT_LINKS
+ int parent;
+#endif
+} jsmntok_t;
+
+/**
+ * JSON parser. Contains an array of token blocks available. Also stores
+ * the string being parsed now and current position in that string.
+ */
+typedef struct jsmn_parser {
+ unsigned int pos; /* offset in the JSON string */
+ unsigned int toknext; /* next token to allocate */
+ int toksuper; /* superior token node, e.g. parent object or array */
+} jsmn_parser;
+
+/**
+ * Create JSON parser over an array of tokens
+ */
+JSMN_API void jsmn_init(jsmn_parser *parser);
+
+/**
+ * Run JSON parser. It parses a JSON data string into and array of tokens, each
+ * describing
+ * a single JSON object.
+ */
+JSMN_API int jsmn_parse(jsmn_parser *parser, const char *js, const size_t len,
+ jsmntok_t *tokens, const unsigned int num_tokens);
+
+#ifndef JSMN_HEADER
+/**
+ * Allocates a fresh unused token from the token pool.
+ */
+static jsmntok_t *jsmn_alloc_token(jsmn_parser *parser, jsmntok_t *tokens,
+ const size_t num_tokens) {
+ jsmntok_t *tok;
+ if (parser->toknext >= num_tokens) {
+ return NULL;
+ }
+ tok = &tokens[parser->toknext++];
+ tok->start = tok->end = -1;
+ tok->size = 0;
+#ifdef JSMN_PARENT_LINKS
+ tok->parent = -1;
+#endif
+ return tok;
+}
+
+/**
+ * Fills token type and boundaries.
+ */
+static void jsmn_fill_token(jsmntok_t *token, const jsmntype_t type,
+ const int start, const int end) {
+ token->type = type;
+ token->start = start;
+ token->end = end;
+ token->size = 0;
+}
+
+/**
+ * Fills next available token with JSON primitive.
+ */
+static int jsmn_parse_primitive(jsmn_parser *parser, const char *js,
+ const size_t len, jsmntok_t *tokens,
+ const size_t num_tokens) {
+ jsmntok_t *token;
+ int start;
+
+ start = parser->pos;
+
+ for (; parser->pos < len && js[parser->pos] != '\0';
parser->pos++) {
+ switch (js[parser->pos]) {
+#ifndef JSMN_STRICT
+ /* In strict mode primitive must be followed by "," or "}" or
"]" */
+ case ':':
+#endif
+ case '\t':
+ case '\r':
+ case '\n':
+ case ' ':
+ case ',':
+ case ']':
+ case '}':
+ goto found;
+ default:
+ /* to quiet a warning from gcc*/
+ break;
+ }
+ if (js[parser->pos] < 32 || js[parser->pos] >= 127) {
+ parser->pos = start;
+ return JSMN_ERROR_INVAL;
+ }
+ }
+#ifdef JSMN_STRICT
+ /* In strict mode primitive must be followed by a comma/object/array */
+ parser->pos = start;
+ return JSMN_ERROR_PART;
+#endif
+
+found:
+ if (tokens == NULL) {
+ parser->pos--;
+ return 0;
+ }
+ token = jsmn_alloc_token(parser, tokens, num_tokens);
+ if (token == NULL) {
+ parser->pos = start;
+ return JSMN_ERROR_NOMEM;
+ }
+ jsmn_fill_token(token, JSMN_PRIMITIVE, start, parser->pos);
+#ifdef JSMN_PARENT_LINKS
+ token->parent = parser->toksuper;
+#endif
+ parser->pos--;
+ return 0;
+}
+
+/**
+ * Fills next token with JSON string.
+ */
+static int jsmn_parse_string(jsmn_parser *parser, const char *js,
+ const size_t len, jsmntok_t *tokens,
+ const size_t num_tokens) {
+ jsmntok_t *token;
+
+ int start = parser->pos;
+
+ /* Skip starting quote */
+ parser->pos++;
+
+ for (; parser->pos < len && js[parser->pos] != '\0';
parser->pos++) {
+ char c = js[parser->pos];
+
+ /* Quote: end of string */
+ if (c == '\"') {
+ if (tokens == NULL) {
+ return 0;
+ }
+ token = jsmn_alloc_token(parser, tokens, num_tokens);
+ if (token == NULL) {
+ parser->pos = start;
+ return JSMN_ERROR_NOMEM;
+ }
+ jsmn_fill_token(token, JSMN_STRING, start + 1, parser->pos);
+#ifdef JSMN_PARENT_LINKS
+ token->parent = parser->toksuper;
+#endif
+ return 0;
+ }
+
+ /* Backslash: Quoted symbol expected */
+ if (c == '\\' && parser->pos + 1 < len) {
+ int i;
+ parser->pos++;
+ switch (js[parser->pos]) {
+ /* Allowed escaped symbols */
+ case '\"':
+ case '/':
+ case '\\':
+ case 'b':
+ case 'f':
+ case 'r':
+ case 'n':
+ case 't':
+ break;
+ /* Allows escaped symbol \uXXXX */
+ case 'u':
+ parser->pos++;
+ for (i = 0; i < 4 && parser->pos < len &&
js[parser->pos] != '\0';
+ i++) {
+ /* If it isn't a hex character we have an error */
+ if (!((js[parser->pos] >= 48 && js[parser->pos] <= 57) ||
/* 0-9 */
+ (js[parser->pos] >= 65 && js[parser->pos] <= 70) ||
/* A-F */
+ (js[parser->pos] >= 97 && js[parser->pos] <= 102))) {
/* a-f */
+ parser->pos = start;
+ return JSMN_ERROR_INVAL;
+ }
+ parser->pos++;
+ }
+ parser->pos--;
+ break;
+ /* Unexpected symbol */
+ default:
+ parser->pos = start;
+ return JSMN_ERROR_INVAL;
+ }
+ }
+ }
+ parser->pos = start;
+ return JSMN_ERROR_PART;
+}
+
+/**
+ * Parse JSON string and fill tokens.
+ */
+JSMN_API int jsmn_parse(jsmn_parser *parser, const char *js, const size_t len,
+ jsmntok_t *tokens, const unsigned int num_tokens) {
+ int r;
+ int i;
+ jsmntok_t *token;
+ int count = parser->toknext;
+
+ for (; parser->pos < len && js[parser->pos] != '\0';
parser->pos++) {
+ char c;
+ jsmntype_t type;
+
+ c = js[parser->pos];
+ switch (c) {
+ case '{':
+ case '[':
+ count++;
+ if (tokens == NULL) {
+ break;
+ }
+ token = jsmn_alloc_token(parser, tokens, num_tokens);
+ if (token == NULL) {
+ return JSMN_ERROR_NOMEM;
+ }
+ if (parser->toksuper != -1) {
+ jsmntok_t *t = &tokens[parser->toksuper];
+#ifdef JSMN_STRICT
+ /* In strict mode an object or array can't become a key */
+ if (t->type == JSMN_OBJECT) {
+ return JSMN_ERROR_INVAL;
+ }
+#endif
+ t->size++;
+#ifdef JSMN_PARENT_LINKS
+ token->parent = parser->toksuper;
+#endif
+ }
+ token->type = (c == '{' ? JSMN_OBJECT : JSMN_ARRAY);
+ token->start = parser->pos;
+ parser->toksuper = parser->toknext - 1;
+ break;
+ case '}':
+ case ']':
+ if (tokens == NULL) {
+ break;
+ }
+ type = (c == '}' ? JSMN_OBJECT : JSMN_ARRAY);
+#ifdef JSMN_PARENT_LINKS
+ if (parser->toknext < 1) {
+ return JSMN_ERROR_INVAL;
+ }
+ token = &tokens[parser->toknext - 1];
+ for (;;) {
+ if (token->start != -1 && token->end == -1) {
+ if (token->type != type) {
+ return JSMN_ERROR_INVAL;
+ }
+ token->end = parser->pos + 1;
+ parser->toksuper = token->parent;
+ break;
+ }
+ if (token->parent == -1) {
+ if (token->type != type || parser->toksuper == -1) {
+ return JSMN_ERROR_INVAL;
+ }
+ break;
+ }
+ token = &tokens[token->parent];
+ }
+#else
+ for (i = parser->toknext - 1; i >= 0; i--) {
+ token = &tokens[i];
+ if (token->start != -1 && token->end == -1) {
+ if (token->type != type) {
+ return JSMN_ERROR_INVAL;
+ }
+ parser->toksuper = -1;
+ token->end = parser->pos + 1;
+ break;
+ }
+ }
+ /* Error if unmatched closing bracket */
+ if (i == -1) {
+ return JSMN_ERROR_INVAL;
+ }
+ for (; i >= 0; i--) {
+ token = &tokens[i];
+ if (token->start != -1 && token->end == -1) {
+ parser->toksuper = i;
+ break;
+ }
+ }
+#endif
+ break;
+ case '\"':
+ r = jsmn_parse_string(parser, js, len, tokens, num_tokens);
+ if (r < 0) {
+ return r;
+ }
+ count++;
+ if (parser->toksuper != -1 && tokens != NULL) {
+ tokens[parser->toksuper].size++;
+ }
+ break;
+ case '\t':
+ case '\r':
+ case '\n':
+ case ' ':
+ break;
+ case ':':
+ parser->toksuper = parser->toknext - 1;
+ break;
+ case ',':
+ if (tokens != NULL && parser->toksuper != -1 &&
+ tokens[parser->toksuper].type != JSMN_ARRAY &&
+ tokens[parser->toksuper].type != JSMN_OBJECT) {
+#ifdef JSMN_PARENT_LINKS
+ parser->toksuper = tokens[parser->toksuper].parent;
+#else
+ for (i = parser->toknext - 1; i >= 0; i--) {
+ if (tokens[i].type == JSMN_ARRAY || tokens[i].type == JSMN_OBJECT) {
+ if (tokens[i].start != -1 && tokens[i].end == -1) {
+ parser->toksuper = i;
+ break;
+ }
+ }
+ }
+#endif
+ }
+ break;
+#ifdef JSMN_STRICT
+ /* In strict mode primitives are: numbers and booleans */
+ case '-':
+ case '0':
+ case '1':
+ case '2':
+ case '3':
+ case '4':
+ case '5':
+ case '6':
+ case '7':
+ case '8':
+ case '9':
+ case 't':
+ case 'f':
+ case 'n':
+ /* And they must not be keys of the object */
+ if (tokens != NULL && parser->toksuper != -1) {
+ const jsmntok_t *t = &tokens[parser->toksuper];
+ if (t->type == JSMN_OBJECT ||
+ (t->type == JSMN_STRING && t->size != 0)) {
+ return JSMN_ERROR_INVAL;
+ }
+ }
+#else
+ /* In non-strict mode every unquoted value is a primitive */
+ default:
+#endif
+ r = jsmn_parse_primitive(parser, js, len, tokens, num_tokens);
+ if (r < 0) {
+ return r;
+ }
+ count++;
+ if (parser->toksuper != -1 && tokens != NULL) {
+ tokens[parser->toksuper].size++;
+ }
+ break;
+
+#ifdef JSMN_STRICT
+ /* Unexpected char in strict mode */
+ default:
+ return JSMN_ERROR_INVAL;
+#endif
+ }
+ }
+
+ if (tokens != NULL) {
+ for (i = parser->toknext - 1; i >= 0; i--) {
+ /* Unmatched opened object or array */
+ if (tokens[i].start != -1 && tokens[i].end == -1) {
+ return JSMN_ERROR_PART;
+ }
+ }
+ }
+
+ return count;
+}
+
+/**
+ * Creates a new parser based over a given buffer with an array of tokens
+ * available.
+ */
+JSMN_API void jsmn_init(jsmn_parser *parser) {
+ parser->pos = 0;
+ parser->toknext = 0;
+ parser->toksuper = -1;
+}
+
+#endif /* JSMN_HEADER */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* JSMN_H */
--
2.31.1
8:36 a.m.
New subject: [PATCH v2 2/3] json: introduce JSON module
This is a minimal wrapper around jsmn.h to make things a bit easier
for iterating through a JSON object.
An iterator can be created/destroyed with json_iter_{new,free} and
values can be parsed from this iterator using json_iter_parse.
Arguments to json_iter_parse should use JSON_MANDATORY/JSON_OPTIONAL
macros, and terminate the argument list with JSON_FLAG_INVALID.
The value pointer in the MANDATORY/OPTIONAL macros can be NULL, in
which case the presence of the key/value is checked but no data is
returned out.
Currently only JSON_STRING and JSON_OBJECT types are supported. String
values should be of type struct iovec *, and objects should be of
type struct json_iter **. These nested objects can be parsed again
using json_iter_parse and should not be freed (the original iterator
keeps track of nested object iterators).
---
Makefile.am | 1 +
src/json.c | 222 ++++++++++++++++++++++++++++++++++++++++++++++++++++
src/json.h | 84 ++++++++++++++++++++
3 files changed, 307 insertions(+)
create mode 100644 src/json.c
create mode 100644 src/json.h
v2:
* Re-wrote to remove callback style parsing. Instead the expected values
are provided to the parser directly.
diff --git a/Makefile.am b/Makefile.am
index 7fe4b5c3..1ae7e3c0 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -249,6 +249,7 @@ src_iwd_SOURCES = src/main.c linux/nl80211.h src/iwd.h src/missing.h
\
src/sysfs.h src/sysfs.c \
src/offchannel.h src/offchannel.c \
src/dpp-util.h src/dpp-util.c \
+ src/json.h src/json.c \
$(eap_sources) \
$(builtin_sources)
diff --git a/src/json.c b/src/json.c
new file mode 100644
index 00000000..9f6c744f
--- /dev/null
+++ b/src/json.c
@@ -0,0 +1,222 @@
+/*
+ *
+ * Wireless daemon for Linux
+ *
+ * Copyright (C) 2013-2019 Intel Corporation. All rights reserved.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <errno.h>
+
+#include <ell/ell.h>
+
+#include "src/json.h"
+
+#include "shared/jsmn.h"
+
+/* Max number of tokens supported. Increase if larger objects are expected */
+#define JSON_DEFAULT_TOKENS 30
+
+#define TOK_LEN(token) (token)->end - (token)->start
+#define TOK_PTR(json, token) (void *)((json) + (token)->start)
+
+struct json_iter {
+ const char *json;
+ size_t json_len;
+ jsmntok_t *tokens;
+ int tokens_len;
+ jsmn_parser *p;
+ struct l_queue *children;
+ bool root : 1;
+};
+
+static struct json_iter *iter_recurse(struct json_iter *parent,
+ jsmntok_t *object)
+{
+ struct json_iter *iter = l_new(struct json_iter, 1);
+
+ iter->json = parent->json;
+ iter->json_len = parent->json_len;
+ iter->tokens = object;
+ iter->children = l_queue_new();
+
+ /*
+ * Since object->size only indicates the number of keys in an object
+ * we cannot easily calculate the number of tokens remaining (for this
+ * object) since each object may have nested objects. Set tokens_len to
+ * the number of tokens remaining in the overall list after 'object'
+ */
+ iter->tokens_len = parent->tokens_len -
+ ((object - parent->tokens) % sizeof(jsmntok_t));
+
+ l_queue_push_head(parent->children, iter);
+
+ return iter;
+}
+
+struct json_iter *json_iter_new(const char *json, size_t json_len)
+{
+ struct json_iter *iter = l_new(struct json_iter, 1);
+
+ iter->json = json;
+ iter->json_len = json_len;
+ iter->p = l_new(jsmn_parser, 1);
+ iter->tokens = l_new(jsmntok_t, JSON_DEFAULT_TOKENS);
+ iter->root = true;
+
+ jsmn_init(iter->p);
+ iter->tokens_len = jsmn_parse(iter->p, iter->json, iter->json_len,
+ iter->tokens, JSON_DEFAULT_TOKENS);
+ if (iter->tokens_len < 0) {
+ json_iter_free(iter);
+ return NULL;
+ }
+
+ iter->children = l_queue_new();
+
+ return iter;
+}
+
+static void json_iter_destroy(void *data)
+{
+ struct json_iter *iter = data;
+
+ json_iter_free(iter);
+}
+
+void json_iter_free(struct json_iter *iter)
+{
+ if (iter->root) {
+ l_free(iter->p);
+ l_free(iter->tokens);
+ }
+
+ l_queue_destroy(iter->children, json_iter_destroy);
+ l_free(iter);
+}
+
+static jsmntok_t *next_key(struct json_iter *iter, jsmntok_t *current)
+{
+ jsmntok_t *value;
+ int i;
+
+ /*
+ * In theory JSMN should prevent any of these bounds checks from failing
+ */
+ if (current + 1 > iter->tokens + iter->tokens_len)
+ return NULL;
+
+ value = current + 1;
+
+ if (value->size == 0)
+ return value + 1;
+
+ for (i = 0; i < value->size; i++)
+ value = next_key(iter, value);
+
+ return value;
+}
+
+/*
+ * Checks that the keys value (t + 1) is in bounds, the value type matches,
+ * key length matches, and key string match
+ */
+#define TOKEN_MATCHES(iter, t, key, type) \
+ (t) + 1 < iter->tokens + iter->tokens_len && \
+ (jsmntype_t)(type) == ((t) + 1)->type && \
+ TOK_LEN((t)) == (int)strlen((key)) && \
+ !memcmp(TOK_PTR((iter)->json, (t)), (key), TOK_LEN((t)))
+
+bool json_iter_parse(struct json_iter *iter, ...)
+{
+ va_list va;
+ int i;
+ int num = iter->tokens->size;
+ jsmntok_t *next;
+ struct iovec *sval;
+ struct json_iter **oval;
+
+ /* Empty object {} */
+ if (iter->tokens_len < 1)
+ return false;
+
+ va_start(va, iter);
+
+ while (true) {
+ enum json_flag flag;
+ char *key;
+ enum json_type type;
+ void *value;
+ jsmntok_t *v = NULL;
+
+ flag = va_arg(va, enum json_flag);
+
+ if (flag == JSON_FLAG_INVALID)
+ break;
+
+ key = va_arg(va, char *);
+ type = va_arg(va, enum json_type);
+ value = va_arg(va, void *);
+
+ next = iter->tokens + 1;
+
+ /* Iterate over this objects keys */
+ for (i = 0; i < num; i++) {
+ if (TOKEN_MATCHES(iter, next, key, type)) {
+ v = next + 1;
+ break;
+ }
+
+ next = next_key(iter, next);
+ if (!next)
+ return false;
+ }
+
+ if (flag == JSON_FLAG_MANDATORY && !v)
+ return false;
+
+ switch (type) {
+ case JSON_STRING:
+ if (!value)
+ continue;
+
+ sval = value;
+ sval->iov_base = v ? TOK_PTR(iter->json, v) : NULL;
+ sval->iov_len = v ? TOK_LEN(v) : 0;
+
+ break;
+ case JSON_OBJECT:
+ if (!value)
+ continue;
+
+ oval = value;
+ *oval = v ? iter_recurse(iter, v) : NULL;
+
+ break;
+ default:
+ return false;
+ }
+ }
+
+ va_end(va);
+
+ return true;
+}
diff --git a/src/json.h b/src/json.h
new file mode 100644
index 00000000..202445ee
--- /dev/null
+++ b/src/json.h
@@ -0,0 +1,84 @@
+/*
+ *
+ * Wireless daemon for Linux
+ *
+ * Copyright (C) 2021 Intel Corporation. All rights reserved.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ */
+
+struct json_iter;
+
+/*
+ * Identical to JSMN types
+ */
+enum json_type {
+ JSON_UNDEFINED = 0,
+ JSON_OBJECT = 1 << 0,
+ JSON_ARRAY = 1 << 1,
+ JSON_STRING = 1 << 2,
+ JSON_PRIMITIVE = 1 << 3
+};
+
+enum json_flag {
+ JSON_FLAG_INVALID = 0,
+ JSON_FLAG_MANDATORY = 1,
+ JSON_FLAG_OPTIONAL = 2,
+};
+
+#define JSON_MANDATORY(key, type, out) \
+ JSON_FLAG_MANDATORY, (key), (type), (out)
+
+#define JSON_OPTIONAL(key, type, out) \
+ JSON_FLAG_OPTIONAL, (key), (type), (out)
+
+#define JSON_STR_EQ(iov, s) \
+ ((iov)->iov_len == strlen((s)) && \
+ !memcmp((iov)->iov_base, (s), (iov)->iov_len))
+
+#define JSON_TO_STR(iov) \
+({ \
+ char *_tmp = l_malloc((iov)->iov_len + 1); \
+ memcpy(_tmp, (iov)->iov_base, (iov)->iov_len); \
+ _tmp[(iov)->iov_len] = '\0'; \
+ _tmp; \
+})
+
+struct json_iter *json_iter_new(const char *json, size_t json_len);
+void json_iter_free(struct json_iter *iter);
+
+/*
+ * Parse an arbitrary number of key/value pairs from a JSON iterator. Initially
+ * a new JSON iterator should be created with json_iter_new() and, when done,
+ * freed with json_iter_free. Nested objects are also parsed with this function
+ * but these iterators should not be freed and are tracked by the original
+ * iterator.
+ *
+ * Arguments should be specified using JSON_MANDATORY or JSON_OPTIONAL:
+ *
+ * r = json_iter_parse(iter, JSON_MANDATORY("mykey", JSON_STRING,
&strvalue),
+ * JSON_OPTIONAL("optkey", JSON_STRING, &optvalue));
+ *
+ * String values should be of type struct iovec *
+ * Object values should be of type struct json_iter **
+ *
+ * No other types are supported at this time, and json_iter_parse will fail if
+ * other types are encountered.
+ *
+ * JSON_OPTIONAL string values will have a NULL/0 iov_base/iov_len if they were
+ * not found. JSON_OPTIONAL object value iterators will be NULL if not found.
+ */
+bool json_iter_parse(struct json_iter *iter, ...);
--
2.31.1
4:52 a.m.
New subject: [PATCH v2 2/3] json: introduce JSON module
Hi James,
On 12/8/21 3:36 PM, James Prestwood wrote:
This is a minimal wrapper around jsmn.h to make things a bit easier
for iterating through a JSON object.
An iterator can be created/destroyed with json_iter_{new,free} and
values can be parsed from this iterator using json_iter_parse.
Have you considered using an intermediate object to hold the bits that need to
be opaque? That way json_iter objects could be public and held on the stack.
Would make things easier to use / simpler to implement.
So roughly:
struct json_contents;
struct json_iter {
struct json_contents *contents;
int begin;
int end;
};
also you could possibly track parent objects if needed.
Arguments to json_iter_parse should use JSON_MANDATORY/JSON_OPTIONAL
macros, and terminate the argument list with JSON_FLAG_INVALID.
The value pointer in the MANDATORY/OPTIONAL macros can be NULL, in
which case the presence of the key/value is checked but no data is
returned out.
Currently only JSON_STRING and JSON_OBJECT types are supported. String
values should be of type struct iovec *, and objects should be of
Ok, I wonder if we could allocate the strings instead of having the caller do this.
type struct json_iter **. These nested objects can be parsed again
using json_iter_parse and should not be freed (the original iterator
keeps track of nested object iterators).
It would be nice if these were simply on the stack to cut down the queue management.
---
Makefile.am | 1 +
src/json.c | 222 ++++++++++++++++++++++++++++++++++++++++++++++++++++
src/json.h | 84 ++++++++++++++++++++
3 files changed, 307 insertions(+)
create mode 100644 src/json.c
create mode 100644 src/json.h
v2:
* Re-wrote to remove callback style parsing. Instead the expected values
are provided to the parser directly.
diff --git a/Makefile.am b/Makefile.am
index 7fe4b5c3..1ae7e3c0 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -249,6 +249,7 @@ src_iwd_SOURCES = src/main.c linux/nl80211.h src/iwd.h src/missing.h
\
src/sysfs.h src/sysfs.c \
src/offchannel.h src/offchannel.c \
src/dpp-util.h src/dpp-util.c \
+ src/json.h src/json.c \
$(eap_sources) \
$(builtin_sources)
diff --git a/src/json.c b/src/json.c
new file mode 100644
index 00000000..9f6c744f
--- /dev/null
+++ b/src/json.c
@@ -0,0 +1,222 @@
+/*
+ *
+ * Wireless daemon for Linux
+ *
+ * Copyright (C) 2013-2019 Intel Corporation. All rights reserved.
Please update this
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <errno.h>
+
+#include <ell/ell.h>
+
+#include "src/json.h"
+
+#include "shared/jsmn.h"
+
+/* Max number of tokens supported. Increase if larger objects are expected */
+#define JSON_DEFAULT_TOKENS 30
+
+#define TOK_LEN(token) (token)->end - (token)->start
+#define TOK_PTR(json, token) (void *)((json) + (token)->start)
+
+struct json_iter {
+ const char *json;
+ size_t json_len;
+ jsmntok_t *tokens;
+ int tokens_len;
+ jsmn_parser *p;
+ struct l_queue *children;
+ bool root : 1;
+};
+
+static struct json_iter *iter_recurse(struct json_iter *parent,
+ jsmntok_t *object)
+{
+ struct json_iter *iter = l_new(struct json_iter, 1);
+
+ iter->json = parent->json;
+ iter->json_len = parent->json_len;
+ iter->tokens = object;
+ iter->children = l_queue_new();
+
+ /*
+ * Since object->size only indicates the number of keys in an object
+ * we cannot easily calculate the number of tokens remaining (for this
+ * object) since each object may have nested objects. Set tokens_len to
+ * the number of tokens remaining in the overall list after 'object'
This seems brittle. Can we recursively count the number of tokens for each child?
+ */
+ iter->tokens_len = parent->tokens_len -
+ ((object - parent->tokens) % sizeof(jsmntok_t));
+
+ l_queue_push_head(parent->children, iter);
+
+ return iter;
+}
+
+struct json_iter *json_iter_new(const char *json, size_t json_len)
+{
+ struct json_iter *iter = l_new(struct json_iter, 1);
+
+ iter->json = json;
+ iter->json_len = json_len;
+ iter->p = l_new(jsmn_parser, 1);
Do you need jsmn_init here?
+ iter->tokens = l_new(jsmntok_t, JSON_DEFAULT_TOKENS);
+ iter->root = true;
+
+ jsmn_init(iter->p);
+ iter->tokens_len = jsmn_parse(iter->p, iter->json, iter->json_len,
+ iter->tokens, JSON_DEFAULT_TOKENS);
+ if (iter->tokens_len < 0) {
+ json_iter_free(iter);
+ return NULL;
+ }
+
+ iter->children = l_queue_new();
+
+ return iter;
+}
+
+static void json_iter_destroy(void *data)
+{
+ struct json_iter *iter = data;
+
+ json_iter_free(iter);
+}
+
+void json_iter_free(struct json_iter *iter)
+{
+ if (iter->root) {
+ l_free(iter->p);
+ l_free(iter->tokens);
+ }
+
+ l_queue_destroy(iter->children, json_iter_destroy);
You could do:
l_queue_destroy(iter->children,
(l_queue_destroy_func_t *) json_iter_free);
+ l_free(iter);
+}
+
+static jsmntok_t *next_key(struct json_iter *iter, jsmntok_t *current)
+{
+ jsmntok_t *value;
+ int i;
+
+ /*
+ * In theory JSMN should prevent any of these bounds checks from failing
Not very reassuring :)
+ */
+ if (current + 1 > iter->tokens + iter->tokens_len)
+ return NULL;
+
+ value = current + 1;
+
+ if (value->size == 0)
+ return value + 1;
So value->size == 0 implies a basic type?
+ > + for (i = 0; i < value->size; i++)
+ value = next_key(iter, value);
So this should be recursively skipping tokens when value is non-basic. The
naming is a bit confusing here
+
+ return value;
Since you're returning 'value', but the reader expects a 'key'.
+}
+
+/*
+ * Checks that the keys value (t + 1) is in bounds, the value type matches,
+ * key length matches, and key string match
+ */
+#define TOKEN_MATCHES(iter, t, key, type) \
+ (t) + 1 < iter->tokens + iter->tokens_len && \
+ (jsmntype_t)(type) == ((t) + 1)->type && \
+ TOK_LEN((t)) == (int)strlen((key)) && \
+ !memcmp(TOK_PTR((iter)->json, (t)), (key), TOK_LEN((t)))
+
+bool json_iter_parse(struct json_iter *iter, ...)
+{
+ va_list va;
+ int i;
+ int num = iter->tokens->size;
+ jsmntok_t *next;
+ struct iovec *sval;
+ struct json_iter **oval;
+
+ /* Empty object {} */
+ if (iter->tokens_len < 1)
+ return false;
+
+ va_start(va, iter);
+
+ while (true) {
+ enum json_flag flag;
+ char *key;
+ enum json_type type;
+ void *value;
+ jsmntok_t *v = NULL;
+
+ flag = va_arg(va, enum json_flag);
+
+ if (flag == JSON_FLAG_INVALID)
+ break;
+
+ key = va_arg(va, char *);
+ type = va_arg(va, enum json_type);
+ value = va_arg(va, void *);
+
+ next = iter->tokens + 1;
+
+ /* Iterate over this objects keys */
+ for (i = 0; i < num; i++) {
+ if (TOKEN_MATCHES(iter, next, key, type)) {
+ v = next + 1;
+ break;
What if the key matches but the type doesn't? Shouldn't we bail early?
+ }
+
+ next = next_key(iter, next);
+ if (!next)
+ return false;
May not be as big of a deal in this particular case, but this approach is
side-effecting on failure. You could parse the object part of the way through,
then fail to find a key and bail, but you may have assigned stuff along the way.
+ }
+
+ if (flag == JSON_FLAG_MANDATORY && !v)
+ return false;
+
+ switch (type) {
+ case JSON_STRING:
+ if (!value)
+ continue;
+
+ sval = value;
+ sval->iov_base = v ? TOK_PTR(iter->json, v) : NULL;
+ sval->iov_len = v ? TOK_LEN(v) : 0;
+
+ break;
+ case JSON_OBJECT:
+ if (!value)
+ continue;
+
+ oval = value;
+ *oval = v ? iter_recurse(iter, v) : NULL;
+
+ break;
+ default:
+ return false;
+ }
+ }
+
+ va_end(va);
+
+ return true;
+}
diff --git a/src/json.h b/src/json.h
new file mode 100644
index 00000000..202445ee
--- /dev/null
+++ b/src/json.h
@@ -0,0 +1,84 @@
+/*
+ *
+ * Wireless daemon for Linux
+ *
+ * Copyright (C) 2021 Intel Corporation. All rights reserved.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ */
+
+struct json_iter;
+
+/*
+ * Identical to JSMN types
+ */
+enum json_type {
+ JSON_UNDEFINED = 0,
+ JSON_OBJECT = 1 << 0,
+ JSON_ARRAY = 1 << 1,
+ JSON_STRING = 1 << 2,
+ JSON_PRIMITIVE = 1 << 3
+};
+
+enum json_flag {
+ JSON_FLAG_INVALID = 0,
+ JSON_FLAG_MANDATORY = 1,
+ JSON_FLAG_OPTIONAL = 2,
+};
+
+#define JSON_MANDATORY(key, type, out) \
+ JSON_FLAG_MANDATORY, (key), (type), (out)
+
+#define JSON_OPTIONAL(key, type, out) \
+ JSON_FLAG_OPTIONAL, (key), (type), (out)
+
+#define JSON_STR_EQ(iov, s) \
+ ((iov)->iov_len == strlen((s)) && \
+ !memcmp((iov)->iov_base, (s), (iov)->iov_len))
+
+#define JSON_TO_STR(iov) \
+({ \
+ char *_tmp = l_malloc((iov)->iov_len + 1); \
+ memcpy(_tmp, (iov)->iov_base, (iov)->iov_len); \
+ _tmp[(iov)->iov_len] = '\0'; \
+ _tmp; \
+})
+
+struct json_iter *json_iter_new(const char *json, size_t json_len);
+void json_iter_free(struct json_iter *iter);
+
+/*
+ * Parse an arbitrary number of key/value pairs from a JSON iterator. Initially
+ * a new JSON iterator should be created with json_iter_new() and, when done,
+ * freed with json_iter_free. Nested objects are also parsed with this function
+ * but these iterators should not be freed and are tracked by the original
+ * iterator.
+ *
+ * Arguments should be specified using JSON_MANDATORY or JSON_OPTIONAL:
+ *
+ * r = json_iter_parse(iter, JSON_MANDATORY("mykey", JSON_STRING,
&strvalue),
+ * JSON_OPTIONAL("optkey", JSON_STRING, &optvalue));
+ *
+ * String values should be of type struct iovec *
+ * Object values should be of type struct json_iter **
+ *
+ * No other types are supported at this time, and json_iter_parse will fail if
+ * other types are encountered.
+ *
+ * JSON_OPTIONAL string values will have a NULL/0 iov_base/iov_len if they were
+ * not found. JSON_OPTIONAL object value iterators will be NULL if not found.
+ */
+bool json_iter_parse(struct json_iter *iter, ...);
Just a nit, but it is a bit clearer to start the '...' after either a
printf-style string or an argument that could carry the sentintel value. For
example:
int nl80211_parse_attrs(struct l_genl_msg *msg, int tag, ...);
It isn't much, but gives just a bit extra context for how the API is supposed to
be used. So in the case of json_iter_parse it would be enum json_flag.
Though really, I wonder why json_iter_parse doesn't use the sequence of:
(json_type, key, value, flags) ?
Regards,
-Denis
6:10 a.m.
New subject: [PATCH v2 2/3] json: introduce JSON module
On Thu, 2021-12-09 at 11:52 -0600, Denis Kenzior wrote:
Hi James,
On 12/8/21 3:36 PM, James Prestwood wrote:
> This is a minimal wrapper around jsmn.h to make things a bit easier
> for iterating through a JSON object.
>
> An iterator can be created/destroyed with json_iter_{new,free} and
> values can be parsed from this iterator using json_iter_parse.
>
Have you considered using an intermediate object to hold the bits
that need to
be opaque? That way json_iter objects could be public and held on
the stack.
Would make things easier to use / simpler to implement.
So roughly:
struct json_contents;
struct json_iter {
struct json_contents *contents;
int begin;
int end;
};
This didn't feel consistent with any other iterators on cleanup:
struct json_iter iter;
json_iter_init(&iter, json, json_len);
...
json_iter_free(&iter);
also you could possibly track parent objects if needed.
> Arguments to json_iter_parse should use
> JSON_MANDATORY/JSON_OPTIONAL
> macros, and terminate the argument list with JSON_FLAG_INVALID.
>
> The value pointer in the MANDATORY/OPTIONAL macros can be NULL, in
> which case the presence of the key/value is checked but no data is
> returned out.
>
> Currently only JSON_STRING and JSON_OBJECT types are supported.
> String
> values should be of type struct iovec *, and objects should be of
Ok, I wonder if we could allocate the strings instead of having the
caller do this.
Sure. Initially this was supposed to be a minimal wrapper and the
allocation seemed like too much, but this has evolved :)
> type struct json_iter **. These nested objects can be parsed again
> using json_iter_parse and should not be freed (the original
> iterator
> keeps track of nested object iterators).
It would be nice if these were simply on the stack to cut down the
queue management.
> ---
> Makefile.am | 1 +
> src/json.c | 222
> ++++++++++++++++++++++++++++++++++++++++++++++++++++
> src/json.h | 84 ++++++++++++++++++++
> 3 files changed, 307 insertions(+)
> create mode 100644 src/json.c
> create mode 100644 src/json.h
>
> v2:
> * Re-wrote to remove callback style parsing. Instead the expected
> values
> are provided to the parser directly.
>
> diff --git a/Makefile.am b/Makefile.am
> index 7fe4b5c3..1ae7e3c0 100644
> --- a/Makefile.am
> +++ b/Makefile.am
> @@ -249,6 +249,7 @@ src_iwd_SOURCES = src/main.c linux/nl80211.h
> src/iwd.h src/missing.h \
> src/sysfs.h src/sysfs.c \
> src/offchannel.h
> src/offchannel.c \
> src/dpp-util.h src/dpp-
> util.c \
> + src/json.h src/json.c \
> $(eap_sources) \
> $(builtin_sources)
>
> diff --git a/src/json.c b/src/json.c
> new file mode 100644
> index 00000000..9f6c744f
> --- /dev/null
> +++ b/src/json.c
> @@ -0,0 +1,222 @@
> +/*
> + *
> + * Wireless daemon for Linux
> + *
> + * Copyright (C) 2013-2019 Intel Corporation. All rights
> reserved.
Please update this
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later
> version.
> + *
> + * This library is distributed in the hope that it will be
> useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General
> Public
> + * License along with this library; if not, write to the Free
> Software
> + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
> 02110-1301 USA
> + *
> + */
> +
> +#ifdef HAVE_CONFIG_H
> +#include <config.h>
> +#endif
> +
> +#include <errno.h>
> +
> +#include <ell/ell.h>
> +
> +#include "src/json.h"
> +
> +#include "shared/jsmn.h"
> +
> +/* Max number of tokens supported. Increase if larger objects are
> expected */
> +#define JSON_DEFAULT_TOKENS 30
> +
> +#define TOK_LEN(token) (token)->end - (token)->start
> +#define TOK_PTR(json, token) (void *)((json) + (token)->start)
> +
> +struct json_iter {
> + const char *json;
> + size_t json_len;
> + jsmntok_t *tokens;
> + int tokens_len;
> + jsmn_parser *p;
> + struct l_queue *children;
> + bool root : 1;
> +};
> +
> +static struct json_iter *iter_recurse(struct json_iter *parent,
> + jsmntok_t *object)
> +{
> + struct json_iter *iter = l_new(struct json_iter, 1);
> +
> + iter->json = parent->json;
> + iter->json_len = parent->json_len;
> + iter->tokens = object;
> + iter->children = l_queue_new();
> +
> + /*
> + * Since object->size only indicates the number of keys in
> an object
> + * we cannot easily calculate the number of tokens
> remaining (for this
> + * object) since each object may have nested objects. Set
> tokens_len to
> + * the number of tokens remaining in the overall list after
> 'object'
This seems brittle. Can we recursively count the number of tokens
for each child?
So this is really only for bounds checking, which may not actually be
requred as that comment below suggests. I think so long as we trust
JSMN we can guarantee its parsed tokens will always contain key/value
pairs. Still, a maximum bounds probably doesn't hurt. So yes we can
limit the bounds of these recursive iterators to only the child object.
> + */
> + iter->tokens_len = parent->tokens_len -
> + ((object - parent->tokens) %
> sizeof(jsmntok_t));
> +
> + l_queue_push_head(parent->children, iter);
> +
> + return iter;
> +}
> +
> +struct json_iter *json_iter_new(const char *json, size_t json_len)
> +{
> + struct json_iter *iter = l_new(struct json_iter, 1);
> +
> + iter->json = json;
> + iter->json_len = json_len;
> + iter->p = l_new(jsmn_parser, 1);
Do you need jsmn_init here?
Yes, below.
> + iter->tokens = l_new(jsmntok_t, JSON_DEFAULT_TOKENS);
> + iter->root = true;
> +
> + jsmn_init(iter->p);
> + iter->tokens_len = jsmn_parse(iter->p, iter->json, iter-
> >json_len,
> + iter->tokens,
> JSON_DEFAULT_TOKENS);
> + if (iter->tokens_len < 0) {
> + json_iter_free(iter);
> + return NULL;
> + }
> +
> + iter->children = l_queue_new();
> +
> + return iter;
> +}
> +
> +static void json_iter_destroy(void *data)
> +{
> + struct json_iter *iter = data;
> +
> + json_iter_free(iter);
> +}
> +
> +void json_iter_free(struct json_iter *iter)
> +{
> + if (iter->root) {
> + l_free(iter->p);
> + l_free(iter->tokens);
> + }
> +
> + l_queue_destroy(iter->children, json_iter_destroy);
You could do:
l_queue_destroy(iter->children,
(l_queue_destroy_func_t *) json_iter_free);
> + l_free(iter);
> +}
> +
> +static jsmntok_t *next_key(struct json_iter *iter, jsmntok_t
> *current)
> +{
> + jsmntok_t *value;
> + int i;
> +
> + /*
> + * In theory JSMN should prevent any of these bounds checks
> from failing
Not very reassuring :)
This was more paranoia than anything.
> + */
> + if (current + 1 > iter->tokens + iter->tokens_len)
> + return NULL;
> +
> + value = current + 1;
> +
> + if (value->size == 0)
> + return value + 1;
So value->size == 0 implies a basic type?
AFAIK any value that is not an object will have a size of zero, so this
could include strings as well not just basic types.
> + > + for (i = 0; i < value->size; i++)
> + value = next_key(iter, value);
So this should be recursively skipping tokens when value is non-
basic. The
naming is a bit confusing here
> +
> + return value;
Since you're returning 'value', but the reader expects a 'key'.
Yes, some re-naming is in order. This is actually returning a key
though, I just reused 'value' rather than a new variable. Something
like 'token' or 'tmp' would be better.
> +}
> +
> +/*
> + * Checks that the keys value (t + 1) is in bounds, the value type
> matches,
> + * key length matches, and key string match
> + */
> +#define TOKEN_MATCHES(iter, t, key, type) \
> + (t) + 1 < iter->tokens + iter->tokens_len && \
> + (jsmntype_t)(type) == ((t) + 1)->type && \
> + TOK_LEN((t)) == (int)strlen((key)) && \
> + !memcmp(TOK_PTR((iter)->json, (t)), (key), TOK_LEN((t)))
> +
> +bool json_iter_parse(struct json_iter *iter, ...)
> +{
> + va_list va;
> + int i;
> + int num = iter->tokens->size;
> + jsmntok_t *next;
> + struct iovec *sval;
> + struct json_iter **oval;
> +
> + /* Empty object {} */
> + if (iter->tokens_len < 1)
> + return false;
> +
> + va_start(va, iter);
> +
> + while (true) {
> + enum json_flag flag;
> + char *key;
> + enum json_type type;
> + void *value;
> + jsmntok_t *v = NULL;
> +
> + flag = va_arg(va, enum json_flag);
> +
> + if (flag == JSON_FLAG_INVALID)
> + break;
> +
> + key = va_arg(va, char *);
> + type = va_arg(va, enum json_type);
> + value = va_arg(va, void *);
> +
> + next = iter->tokens + 1;
> +
> + /* Iterate over this objects keys */
> + for (i = 0; i < num; i++) {
> + if (TOKEN_MATCHES(iter, next, key, type)) {
> + v = next + 1;
> + break;
What if the key matches but the type doesn't? Shouldn't we bail
early?
Yep, I'll add some extra checks.
> + }
> +
> + next = next_key(iter, next);
> + if (!next)
> + return false;
May not be as big of a deal in this particular case, but this
approach is
side-effecting on failure. You could parse the object part of the
way through,
then fail to find a key and bail, but you may have assigned stuff
along the way.
Yeah I could not think of a decent way to handle this without iterating
twice (verification first, then assignment) since we lose reference to
the previous set of arguments with each iteration.
> + }
> +
> + if (flag == JSON_FLAG_MANDATORY && !v)
> + return false;
> +
> + switch (type) {
> + case JSON_STRING:
> + if (!value)
> + continue;
> +
> + sval = value;
> + sval->iov_base = v ? TOK_PTR(iter->json, v)
> : NULL;
> + sval->iov_len = v ? TOK_LEN(v) : 0;
> +
> + break;
> + case JSON_OBJECT:
> + if (!value)
> + continue;
> +
> + oval = value;
> + *oval = v ? iter_recurse(iter, v) : NULL;
> +
> + break;
> + default:
> + return false;
> + }
> + }
> +
> + va_end(va);
> +
> + return true;
> +}
> diff --git a/src/json.h b/src/json.h
> new file mode 100644
> index 00000000..202445ee
> --- /dev/null
> +++ b/src/json.h
> @@ -0,0 +1,84 @@
> +/*
> + *
> + * Wireless daemon for Linux
> + *
> + * Copyright (C) 2021 Intel Corporation. All rights reserved.
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later
> version.
> + *
> + * This library is distributed in the hope that it will be
> useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General
> Public
> + * License along with this library; if not, write to the Free
> Software
> + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
> 02110-1301 USA
> + *
> + */
> +
> +struct json_iter;
> +
> +/*
> + * Identical to JSMN types
> + */
> +enum json_type {
> + JSON_UNDEFINED = 0,
> + JSON_OBJECT = 1 << 0,
> + JSON_ARRAY = 1 << 1,
> + JSON_STRING = 1 << 2,
> + JSON_PRIMITIVE = 1 << 3
> +};
> +
> +enum json_flag {
> + JSON_FLAG_INVALID = 0,
> + JSON_FLAG_MANDATORY = 1,
> + JSON_FLAG_OPTIONAL = 2,
> +};
> +
> +#define JSON_MANDATORY(key, type, out) \
> + JSON_FLAG_MANDATORY, (key), (type), (out)
> +
> +#define JSON_OPTIONAL(key, type, out) \
> + JSON_FLAG_OPTIONAL, (key), (type), (out)
> +
> +#define JSON_STR_EQ(iov, s) \
> + ((iov)->iov_len == strlen((s)) && \
> + !memcmp((iov)->iov_base, (s), (iov)->iov_len))
> +
> +#define JSON_TO_STR(iov) \
> +({ \
> + char *_tmp = l_malloc((iov)->iov_len + 1); \
> + memcpy(_tmp, (iov)->iov_base, (iov)->iov_len); \
> + _tmp[(iov)->iov_len] = '\0'; \
> + _tmp; \
> +})
> +
> +struct json_iter *json_iter_new(const char *json, size_t
> json_len);
> +void json_iter_free(struct json_iter *iter);
> +
> +/*
> + * Parse an arbitrary number of key/value pairs from a JSON
> iterator. Initially
> + * a new JSON iterator should be created with json_iter_new() and,
> when done,
> + * freed with json_iter_free. Nested objects are also parsed with
> this function
> + * but these iterators should not be freed and are tracked by the
> original
> + * iterator.
> + *
> + * Arguments should be specified using JSON_MANDATORY or
> JSON_OPTIONAL:
> + *
> + * r = json_iter_parse(iter, JSON_MANDATORY("mykey", JSON_STRING,
> &strvalue),
> + * JSON_OPTIONAL("optkey", JSON_STRING,
> &optvalue));
> + *
> + * String values should be of type struct iovec *
> + * Object values should be of type struct json_iter **
> + *
> + * No other types are supported at this time, and json_iter_parse
> will fail if
> + * other types are encountered.
> + *
> + * JSON_OPTIONAL string values will have a NULL/0 iov_base/iov_len
> if they were
> + * not found. JSON_OPTIONAL object value iterators will be NULL if
> not found.
> + */
> +bool json_iter_parse(struct json_iter *iter, ...);
Just a nit, but it is a bit clearer to start the '...' after either a
printf-style string or an argument that could carry the sentintel
value. For
example:
int nl80211_parse_attrs(struct l_genl_msg *msg, int tag, ...);
It isn't much, but gives just a bit extra context for how the API is
supposed to
be used. So in the case of json_iter_parse it would be enum
json_flag.
Though really, I wonder why json_iter_parse doesn't use the sequence
of:
(json_type, key, value, flags) ?
Yeah this is fine, I can reorder them like this and add a new
JSON_INVALID type to signal the end.
Regards,
-Denis
6:23 a.m.
New subject: [PATCH v2 2/3] json: introduce JSON module
Hi James,
> Have you considered using an intermediate object to hold the
bits
> that need to
> be opaque? That way json_iter objects could be public and held on
> the stack.
> Would make things easier to use / simpler to implement.
>
> So roughly:
>
> struct json_contents;
>
> struct json_iter {
> struct json_contents *contents;
> int begin;
> int end;
> };
This didn't feel consistent with any other iterators on cleanup:
struct json_iter iter;
json_iter_init(&iter, json, json_len);
...
json_iter_free(&iter);
Well, you would do something like:
struct json_contents *c;
struct json_iter iter;
struct json_iter nested;
_auto_(l_free) char *foo = NULL;
c = json_contents_new(json, json_len);
json_iter_init(&iter, c);
json_iter_parse(&iter, JSON_STRING, "foo",
&foo, JSON_FLAG_MANDATORY,
JSON_OBJECT, "bar",
&nested, JSON_FLAG_OPTIONAL,
JSON_UNDEFINED);
json_iter_parse(&nested, ...);
json_contents_free(c);
>
> Do you need jsmn_init here?
Yes, below.
Ah right, sorry for the noise.
>
> So value->size == 0 implies a basic type?
AFAIK any value that is not an object will have a size of zero, so this
could include strings as well not just basic types.
So essentially anything that is not a container? integers, strings, etc.
>
>> + > + for (i = 0; i < value->size; i++)
>> + value = next_key(iter, value);
>
> So this should be recursively skipping tokens when value is non-
> basic. The
> naming is a bit confusing here
>
>> +
>> + return value;
>
> Since you're returning 'value', but the reader expects a 'key'.
Yes, some re-naming is in order. This is actually returning a key
though, I just reused 'value' rather than a new variable. Something
like 'token' or 'tmp' would be better.
Right, this is doing the right thing, just nitpicking the variable naming.
> May not be as big of a deal in this particular case, but this
> approach is
> side-effecting on failure. You could parse the object part of the
> way through,
> then fail to find a key and bail, but you may have assigned stuff
> along the way.
Yeah I could not think of a decent way to handle this without iterating
twice (verification first, then assignment) since we lose reference to
the previous set of arguments with each iteration.
You could iterate over the va_arg list, build a temporary structure and perform
the parse. If the parse succeeds, then assign the values in the final step.
Regards,
-Denis
8:36 a.m.
New subject: [PATCH v2 3/3] unit: add JSON unit test
---
Makefile.am | 5 +-
unit/test-json.c | 238 +++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 242 insertions(+), 1 deletion(-)
create mode 100644 unit/test-json.c
diff --git a/Makefile.am b/Makefile.am
index 1ae7e3c0..871499a3 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -396,7 +396,7 @@ unit_tests = unit/test-cmac-aes \
unit/test-ie unit/test-util unit/test-ssid-security \
unit/test-arc4 unit/test-wsc unit/test-eap-mschapv2 \
unit/test-eap-sim unit/test-sae unit/test-p2p unit/test-band \
- unit/test-dpp
+ unit/test-dpp unit/test-json
if CLIENT
unit_tests += unit/test-client
@@ -556,6 +556,9 @@ unit_test_dpp_SOURCES = unit/test-dpp.c src/dpp-util.h src/dpp-util.c
\
unit_test_dpp_LDADD = $(ell_ldadd)
+unit_test_json_SOURCES = unit/test-json.c src/json.h src/json.c shared/jsmn.h
+unit_test_json_LDADD = $(ell_ldadd)
+
TESTS = $(unit_tests)
EXTRA_DIST = src/genbuiltin src/iwd.service.in src/net.connman.iwd.service \
diff --git a/unit/test-json.c b/unit/test-json.c
new file mode 100644
index 00000000..ddc820d5
--- /dev/null
+++ b/unit/test-json.c
@@ -0,0 +1,238 @@
+/*
+ *
+ * Embedded Linux library
+ *
+ * Copyright (C) 2021 Intel Corporation. All rights reserved.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdio.h>
+#include <assert.h>
+
+#include <ell/ell.h>
+
+#include "src/json.h"
+#include "ell/useful.h"
+
+/*
+ * Object:
+ * { "test": "<smile emoji>" }
+ */
+static void test_json_unicode(const void *data)
+{
+ struct json_iter *iter;
+ struct iovec v;
+ uint8_t expected[] = { 0xF0, 0x9F, 0x98, 0x80 };
+
+ uint8_t s[] = { '{', '"', 't', 'e', 's',
't', '"', ':',
+ '"', 0xf0, 0x9f, 0x98, 0x80, '"', '}', 0 };
+
+ iter = json_iter_new((const char *)s, sizeof(s));
+ assert(json_iter_parse(iter, JSON_MANDATORY("test", JSON_STRING, &v),
+ JSON_FLAG_INVALID));
+
+ assert(v.iov_len == sizeof(expected));
+ assert(!memcmp(v.iov_base, expected, sizeof(expected)));
+
+ json_iter_free(iter);
+}
+
+static void test_json_escaped_unicode(const void *data)
+{
+ struct json_iter *iter;
+ struct iovec v;
+ char *s = "{\"test\":\"\\uD8F0\"}";
+ char expected[] = "\\uD8F0";
+
+ iter = json_iter_new(s, strlen(s));
+ assert(json_iter_parse(iter, JSON_MANDATORY("test", JSON_STRING, &v),
+ JSON_FLAG_INVALID));
+
+ assert(v.iov_len == strlen(expected));
+ assert(!memcmp(v.iov_base, expected, strlen(expected)));
+
+ json_iter_free(iter);
+}
+
+/*
+ * Tests that unsupported types will not parse
+ */
+static void test_json_unsupported_types(const void *data)
+{
+ /*
+ * Valid JSON objects but currently unsupported types
+ */
+ char arrays[] = "{\"test\":[1, 2, 3, 4]}";
+ char undefs[] = "{\"test\": undefined}";
+ char integers[] = "{\"test\": 10 }";
+ char bools[] = "{\"test\": true}";
+
+ struct json_iter *iter;
+
+ iter = json_iter_new(arrays, strlen(arrays));
+ assert(iter);
+ assert(!json_iter_parse(iter,
+ JSON_MANDATORY("test", JSON_ARRAY, NULL),
+ JSON_FLAG_INVALID));
+
+ iter = json_iter_new(undefs, strlen(undefs));
+ assert(iter);
+ assert(!json_iter_parse(iter,
+ JSON_MANDATORY("test", JSON_UNDEFINED, NULL),
+ JSON_FLAG_INVALID));
+
+ iter = json_iter_new(integers, strlen(integers));
+ assert(iter);
+ assert(!json_iter_parse(iter,
+ JSON_MANDATORY("test", JSON_PRIMITIVE, NULL),
+ JSON_FLAG_INVALID));
+
+ iter = json_iter_new(bools, strlen(bools));
+ assert(iter);
+ assert(!json_iter_parse(iter,
+ JSON_MANDATORY("test", JSON_PRIMITIVE, NULL),
+ JSON_FLAG_INVALID));
+}
+
+#define CHECK_STRING(iov, exp) \
+({ \
+ assert((iov)->iov_len == strlen((exp))); \
+ assert(!memcmp((iov)->iov_base, exp, (iov)->iov_len)); \
+})
+
+/*
+ * Basic test string values and nested objects
+ */
+static void test_json(const void *data)
+{
+ char json[] = "{\"wi-fi_tech\":\"infra\","
+ "\"discovery\":"
+ "{\"ssid\":\"somessid\"},"
+ "\"cred\":"
+ "{\"akm\":\"psk\","
+ "\"pass\":\"somepassphrase\"}}";
+ struct iovec tech;
+ struct iovec ssid;
+ struct iovec akm;
+ struct iovec pass;
+ struct iovec opt_not_found;
+ struct json_iter *discovery, *cred;
+
+ struct json_iter *iter = json_iter_new(json, strlen(json));
+
+ assert(json_iter_parse(iter,
+ JSON_MANDATORY("wi-fi_tech", JSON_STRING, &tech),
+ JSON_MANDATORY("discovery", JSON_OBJECT, &discovery),
+ JSON_MANDATORY("cred", JSON_OBJECT, &cred),
+ JSON_OPTIONAL("notfound", JSON_STRING, &opt_not_found),
+ JSON_FLAG_INVALID));
+
+ assert(opt_not_found.iov_base == 0);
+
+ CHECK_STRING(&tech, "infra");
+
+ assert(json_iter_parse(discovery,
+ JSON_MANDATORY("ssid", JSON_STRING, &ssid),
+ JSON_FLAG_INVALID));
+
+ CHECK_STRING(&ssid, "somessid");
+
+ assert(json_iter_parse(cred,
+ JSON_MANDATORY("akm", JSON_STRING, &akm),
+ JSON_MANDATORY("pass", JSON_STRING, &pass),
+ JSON_FLAG_INVALID));
+
+ CHECK_STRING(&akm, "psk");
+ CHECK_STRING(&pass, "somepassphrase");
+
+ json_iter_free(iter);
+}
+
+/*
+ * Tests empty objects parse successfully
+ */
+static void test_json_empty_objects(const void *data)
+{
+ char empty[] = "{}";
+ char nested_empty[] = "{\"empty\":{}}";
+ struct json_iter *nested_iter;
+ struct json_iter *iter;
+
+ iter = json_iter_new(empty, strlen(empty));
+ assert(json_iter_parse(iter, JSON_FLAG_INVALID));
+ json_iter_free(iter);
+
+ iter = json_iter_new(empty, strlen(empty));
+ assert(json_iter_parse(iter,
+ JSON_OPTIONAL("optional", JSON_OBJECT, NULL),
+ JSON_FLAG_INVALID));
+ json_iter_free(iter);
+
+
+ iter = json_iter_new(empty, strlen(empty));
+ assert(!json_iter_parse(iter,
+ JSON_MANDATORY("optional", JSON_OBJECT, NULL),
+ JSON_FLAG_INVALID));
+ json_iter_free(iter);
+
+
+ iter = json_iter_new(nested_empty, strlen(nested_empty));
+ assert(json_iter_parse(iter,
+ JSON_MANDATORY("empty", JSON_OBJECT, &nested_iter),
+ JSON_FLAG_INVALID));
+ assert(nested_iter);
+ assert(json_iter_parse(nested_iter, JSON_FLAG_INVALID));
+ json_iter_free(iter);
+}
+
+/*
+ * Tests that expected key/values can be provided in an order different than
+ * they appear in the JSON string.
+ */
+static void test_json_out_of_order(const void *data)
+{
+ char object[] =
"{\"key1\":{},\"key2\":\"val2\",\"key3\":\"val3\"}";
+ struct json_iter *iter;
+
+ iter = json_iter_new(object, strlen(object));
+ assert(iter);
+ assert(json_iter_parse(iter,
+ JSON_OPTIONAL("nonexist1", JSON_STRING, NULL),
+ JSON_MANDATORY("key3", JSON_STRING, NULL),
+ JSON_MANDATORY("key2", JSON_STRING, NULL),
+ JSON_OPTIONAL("nonexist2", JSON_OBJECT, NULL),
+ JSON_MANDATORY("key1", JSON_OBJECT, NULL),
+ JSON_FLAG_INVALID));
+}
+
+int main(int argc, char *argv[])
+{
+ l_test_init(&argc, &argv);
+
+ l_test_add("json unicode", test_json_unicode, NULL);
+ l_test_add("json escaped unicode", test_json_escaped_unicode, NULL);
+ l_test_add("json nested objects", test_json, NULL);
+ l_test_add("json unsupported types", test_json_unsupported_types, NULL);
+ l_test_add("json empty objects", test_json_empty_objects, NULL);
+ l_test_add("json parse out of order", test_json_out_of_order, NULL);
+
+ return l_test_run();
+}
--
2.31.1
7:05 a.m.
Hi James,
---
shared/jsmn.h | 471 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 471 insertions(+)
create mode 100644 shared/jsmn.h
the commit message needs to state what version you are adding here. So are you adding
v1.1.0 or just a snapshot of some git tree?
Regards
Marcel
283
days inactive
284
days old
6 comments
3 participants
participants (3)
-
Denis Kenzior -
James Prestwood -
Marcel Holtmann