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 <[email protected]>
Signed-off-by: Ahmad Fatoum <[email protected]>
---
 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


Reply via email to