[PATCH 1/4] lib: add jsmn JSON parser support
Ahmad Fatoum
a.fatoum at pengutronix.de
Tue Jan 10 00:49:27 PST 2023
Board code may require JSON support to parse factory data or to verify
JSON web tokens in locked-down systems. Import the current master
state[1] of JSMN, a minimalistic JSON parser, with slight changes
to make it compile in barebox
[1]: https://github.com/zserge/jsmn/commit/25647e6
Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
---
include/jsmn.h | 91 ++++++++++++
lib/Kconfig | 5 +
lib/Makefile | 1 +
lib/jsmn.c | 371 +++++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 468 insertions(+)
create mode 100644 include/jsmn.h
create mode 100644 lib/jsmn.c
diff --git a/include/jsmn.h b/include/jsmn.h
new file mode 100644
index 000000000000..394ffc467487
--- /dev/null
+++ b/include/jsmn.h
@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright (c) 2010 Serge Zaitsev
+ */
+#ifndef __JSMN_H_
+#define __JSMN_H_
+
+#define JSMN_STRICT
+#define JSMN_PARENT_LINKS
+
+#include <stddef.h>
+#include <errno.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 = -ENOMEM,
+ /* Invalid character inside JSON string */
+ JSMN_ERROR_INVAL = -EINVAL,
+ /* The string is not a full JSON packet, more bytes expected */
+ JSMN_ERROR_PART = -EMSGSIZE
+};
+
+/**
+ * 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);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* JSMN_H */
diff --git a/lib/Kconfig b/lib/Kconfig
index a0f28b935cf7..5af7ea33f27b 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -8,6 +8,11 @@ config UNCOMPRESS
bool
select FILETYPE
+config JSMN
+ bool "JSMN JSON Parser" if COMPILE_TEST
+ help
+ A minimalistic JSON parser.
+
config XXHASH
bool
diff --git a/lib/Makefile b/lib/Makefile
index 21afb233facd..4717b8aec364 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -19,6 +19,7 @@ obj-y += readkey.o
obj-y += kfifo.o
obj-y += libbb.o
obj-y += libgen.o
+obj-$(CONFIG_JSMN) += jsmn.o
obj-$(CONFIG_BLOBGEN) += blobgen.o
obj-y += stringlist.o
obj-y += cmdlinepart.o
diff --git a/lib/jsmn.c b/lib/jsmn.c
new file mode 100644
index 000000000000..3a68f89337fc
--- /dev/null
+++ b/lib/jsmn.c
@@ -0,0 +1,371 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright (c) 2010 Serge Zaitsev
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <jsmn.h>
+
+/**
+ * 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;
+}
--
2.30.2
More information about the barebox
mailing list