ACK: [PATCH 1/2][V2] Replace json-c library with minimal replacement

ivanhu ivan.hu at canonical.com
Mon Aug 24 02:16:38 UTC 2020



On 8/22/20 6:57 PM, Colin King wrote:
> From: Colin Ian King <colin.king at canonical.com>
> 
> FWTS uses a subset of json-c functionality, so replace it with
> our own implementation that supports this subset. This also
> removes the dependency of two flavours of json libraries that
> fwts has been using and also allows us to perform deeper memory
> allocation and leaking tracking with static analysis tools.
> 
> Signed-off-by: Colin Ian King <colin.king at canonical.com>
> ---
> 
> V2: Add missing include files in kernelscan.c
> 
> ---
>  configure.ac                |   3 -
>  src/lib/include/fwts.h      |   2 +
>  src/lib/include/fwts_json.h |  61 ++-
>  src/lib/src/Makefile.am     |   1 +
>  src/lib/src/fwts_json.c     | 917 ++++++++++++++++++++++++++++++++++++
>  src/utilities/Makefile.am   |   5 +-
>  src/utilities/kernelscan.c  |   3 +-
>  7 files changed, 971 insertions(+), 21 deletions(-)
>  create mode 100644 src/lib/src/fwts_json.c
> 
> diff --git a/configure.ac b/configure.ac
> index 39a445cd..f40c3678 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -9,8 +9,6 @@
>  	  AC_PROG_LIBTOOL
>  	  AC_C_INLINE
>  	  AM_PROG_CC_C_O
> -	  AC_SEARCH_LIBS([json_object_from_file], [json json-c], [], [ AC_MSG_ERROR([no available json library]) ])
> -	  AC_SEARCH_LIBS([json_object_object_get_ex], [json json-c], [ AC_DEFINE([JSON_HAS_GET_EX], [1], [Define if we have json_object_object_get_ex])], [])
>    	  AC_CHECK_FUNCS([localtime_r])
>  	  AC_CHECK_FUNCS([dup2])
>  	  AC_CHECK_FUNCS([getcwd])
> @@ -61,7 +59,6 @@
>  	  AC_CHECK_HEADERS([time.h])
>  	  AC_CHECK_HEADERS([sys/ioctl.h])
>  	  AC_CHECK_HEADERS([sys/time.h])
> -	  AC_CHECK_HEADERS([json/json.h])
>  	  AC_CHECK_HEADERS([glib.h])
>  	  AC_CHECK_HEADERS([gio/gio.h])
>  	  AC_CHECK_HEADERS([asm/opal-prd.h])
> diff --git a/src/lib/include/fwts.h b/src/lib/include/fwts.h
> index 1e0d5870..6f13d262 100644
> --- a/src/lib/include/fwts.h
> +++ b/src/lib/include/fwts.h
> @@ -153,6 +153,8 @@
>  
>  #define FWTS_JSON_DATA_PATH	DATAROOTDIR "/fwts"
>  
> +#include <inttypes.h>
> +
>  #include "fwts_version.h"
>  #include "fwts_backtrace.h"
>  #include "fwts_types.h"
> diff --git a/src/lib/include/fwts_json.h b/src/lib/include/fwts_json.h
> index ad51bc45..0c316e02 100644
> --- a/src/lib/include/fwts_json.h
> +++ b/src/lib/include/fwts_json.h
> @@ -1,5 +1,5 @@
>  /*
> - * Copyright (C) 2012-2020 Canonical
> + * Copyright (C) 2010-2020 Canonical
>   *
>   * This program is free software; you can redistribute it and/or
>   * modify it under the terms of the GNU General Public License
> @@ -16,26 +16,15 @@
>   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
>   *
>   */
> -
>  #ifndef __FWTS_JSON_H__
>  #define __FWTS_JSON_H__
>  
> -#include <json.h>
> -
> -#define __FWTS_JSON_ERR_PTR__ ((json_object*) -1)
>  /*
> - *  Older versions of json-c may return an error in an
> - *  object as a ((json_object*)-1), where as newer
> - *  versions return NULL, so check for these. Sigh.
> + *  Minimal subset of json for fwts
>   */
> -#define FWTS_JSON_ERROR(ptr) \
> -	( (ptr == NULL) || ((const json_object *)ptr == __FWTS_JSON_ERR_PTR__) )
>  
> -/*
> - * json-c 0.13.99 does not define TRUE/FALSE anymore
> - * the json-c maintainers replaced them with pure 1/0
> - * https://github.com/json-c/json-c/commit/0992aac61f8b
> - */
> +#define FWTS_JSON_ERROR(ptr) 	(!ptr)
> +
>  #ifndef FALSE
>  #define FALSE 0
>  #endif
> @@ -44,4 +33,46 @@
>  #define TRUE  1
>  #endif
>  
> +/*
> + *  json types supported
> + */
> +typedef enum {
> +	type_null,
> +	type_int,
> +	type_string,
> +	type_object,
> +	type_array,
> +} json_type;
> +
> +/*
> + *  json object information
> + */
> +typedef struct json_object {
> +	char *key;		/* Null if undefined */
> +	int length;		/* Length of a collection of objects */
> +	json_type type;		/* Object type */
> +        union {
> +                void *ptr;	/* string or object array pointer */
> +                int  intval;	/* integer value */
> +        } u;
> +} json_object;
> +
> +/*
> + *  minimal json c library functions as required by fwts
> + */
> +json_object *json_object_from_file(const char *filename);
> +json_object *json_object_object_get(json_object *obj, const char *key);
> +int json_object_array_length(json_object *obj);
> +json_object *json_object_array_get_idx(json_object *obj, int index);
> +const char *json_object_get_string(json_object *obj);
> +json_object *json_object_new_int(int);
> +void json_object_object_add(json_object *obj, const char *key, json_object *value);
> +
> +json_object *json_object_new_object(void);
> +json_object *json_object_new_array(void);
> +char *json_object_to_json_string(json_object *obj);
> +void json_object_put(json_object *obj);
> +json_object *json_object_new_string(const char *str);
> +int json_object_array_add(json_object *obj, json_object *item);
> +
>  #endif
> diff --git a/src/lib/src/Makefile.am b/src/lib/src/Makefile.am
> index ecc4136b..4593bb82 100644
> --- a/src/lib/src/Makefile.am
> +++ b/src/lib/src/Makefile.am
> @@ -82,6 +82,7 @@ libfwts_la_SOURCES = 		\
>  	fwts_interactive.c 	\
>  	fwts_ioport.c		\
>  	fwts_ipmi.c		\
> +	fwts_json.c		\
>  	fwts_keymap.c 		\
>  	fwts_klog.c 		\
>  	fwts_olog.c		\
> diff --git a/src/lib/src/fwts_json.c b/src/lib/src/fwts_json.c
> new file mode 100644
> index 00000000..b92a241a
> --- /dev/null
> +++ b/src/lib/src/fwts_json.c
> @@ -0,0 +1,917 @@
> +/*
> + * Copyright (C) 2010-2020 Canonical
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * as published by the Free Software Foundation; either version 2
> + * of the License, or (at your option) any later version.
> + *
> + * This program 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 General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
> + *
> + * This is a simplified json parser and json object store
> + * based on json but does not support keywords and is designed
> + * just for the fwts json data files. It is not a full json
> + * implementation and should not be used as such.
> + *
> + */
> +#include <stdlib.h>
> +#include <stdio.h>
> +#include <stdarg.h>
> +#include <stdbool.h>
> +#include <string.h>
> +#include <unistd.h>
> +#include <ctype.h>
> +
> +#include "fwts.h"
> +
> +/*
> + *  json file information
> + */
> +typedef struct {
> +	FILE *fp;		/* File pointer */
> +	const char *filename;	/* Name of file */
> +	int linenum;		/* Parser line number */
> +	int charnum;		/* Parser char position */
> +	int error_reported;	/* Error count */
> +} json_file;
> +
> +/*
> + *  json tokens, subset of full json token set as used
> + *  for fwts requirements
> + */
> +typedef enum {
> +	token_lbrace,
> +	token_rbrace,
> +	token_lbracket,
> +	token_rbracket,
> +	token_colon,
> +	token_comma,
> +	token_int,
> +	token_string,
> +	token_true,
> +	token_false,
> +	token_null,
> +	token_error,
> +	token_eof,
> +} json_token_type;
> +
> +/*
> + *  json parser token
> + */
> +typedef struct {
> +	json_token_type type;	/* token type */
> +	long offset;		/* offset in file for re-winding */
> +	union {
> +		char *str;	/* token string value */
> +		int  intval;	/* token integer value */
> +	} u;
> +} json_token;
> +
> +/*
> + *  json_token_string()
> + *	convert json token to a human readable string
> + */
> +char *json_token_string(json_token *jtoken)
> +{
> +	static char tmp[64];
> +
> +	switch (jtoken->type) {
> +	case token_lbrace:
> +		return "{";
> +	case token_rbrace:
> +		return "}";
> +	case token_lbracket:
> +		return "[";
> +	case token_rbracket:
> +		return "]";
> +	case token_colon:
> +		return ":";
> +	case token_comma:
> +		return ",";
> +	case token_int:
> +		(void)snprintf(tmp, sizeof(tmp), "%d", jtoken->u.intval);
> +		return tmp;
> +	case token_string:
> +		return jtoken->u.str;
> +	case token_error:
> +		return "<error>";
> +	case token_eof:
> +		return "end of file";
> +	default:
> +		break;
> +	}
> +	return "<illegal token>";
> +}
> +
> +/*
> + *  json_get_string()
> + *	parse a literal string
> + */
> +json_token_type json_get_string(json_file *jfile, json_token *token)
> +{
> +	char buffer[4096];
> +	size_t i = 0;
> +
> +	for (;;) {
> +		int ch;
> +
> +		ch = fgetc(jfile->fp);
> +		jfile->charnum++;
> +		if (ch == EOF) {
> +			fprintf(stderr, "json_parser: unexpected EOF in literal string\n");
> +			token->u.str = NULL;
> +			return token_error;
> +		}
> +
> +		if (ch == '\\') {
> +			ch = fgetc(jfile->fp);
> +			switch (ch) {
> +			case '\\':
> +			case '"':
> +			case '/':
> +				break;
> +			case 'b':
> +				ch = '\b';
> +				break;
> +			case 'f':
> +				ch = '\f';
> +				break;
> +			case 'n':
> +				ch = '\n';
> +				break;
> +			case 'r':
> +				ch = '\r';
> +				break;
> +			case 't':
> +				ch = '\t';
> +				break;
> +			case 'u':
> +				fprintf(stderr, "json parser: escaped hex values not supported\n");
> +				ch = '?';
> +				break;
> +			}
> +			jfile->charnum++;
> +		} else if (ch == '"') {
> +			buffer[i] = '\0';
> +			token->u.str = strdup(buffer);
> +			if (!token->u.str) {
> +				fprintf(stderr, "json parser: out of memory allocating %zd byte string\n", i);
> +				break;
> +			}
> +			return token_string;
> +		}
> +		buffer[i] = ch;
> +		i++;
> +		if (i >= sizeof(buffer)) {
> +			fprintf(stderr, "json parser: string too long, maximum size %zd bytes\n", sizeof(buffer) - 1);
> +			break;
> +		}
> +	}
> +
> +	token->u.str = NULL;
> +	return token_error;
> +}
> +
> +/*
> + *  json_get_int()
> + *	parse a simple integer
> + */
> +json_token_type json_get_int(json_file *jfile, json_token *token)
> +{
> +	char buffer[64];
> +	size_t i = 0;
> +
> +	for (;;) {
> +		int ch;
> +
> +		ch = fgetc(jfile->fp);
> +		if (!isdigit(ch)) {
> +			(void)ungetc(ch, jfile->fp);
> +			buffer[i] = '\0';
> +			token->u.intval = atoi(buffer);
> +			return token_int;
> +		}
> +		jfile->charnum++;
> +		buffer[i] = ch;
> +		i++;
> +		if (i >= sizeof(buffer)) {
> +			fprintf(stderr, "json parser: integer too long, maximum size %zd bytes\n", sizeof(buffer) - 1);
> +			break;
> +		}
> +	}
> +
> +	token->u.str = NULL;
> +	return token_error;
> +}
> +
> +/*
> + *  json_unget_token()
> + *  	push file pointer back to point before the token
> + *	to unpush the token
> + */
> +int json_unget_token(json_file *jfile, json_token *token)
> +{
> +	return fseek(jfile->fp, token->offset, SEEK_SET);
> +}
> +
> +/*
> + *  json_get_keyword()
> + *	get a keyword
> + */
> +int json_get_keyword(json_file *jfile, json_token *token)
> +{
> +	char buffer[32];
> +	size_t i = 0;
> +
> +	token->u.str = NULL;
> +	*buffer = '\0';
> +
> +	for (;;) {
> +		int ch;
> +
> +		ch = fgetc(jfile->fp);
> +		jfile->charnum++;
> +		if (ch == EOF) {
> +			fprintf(stderr, "json_parser: unexpected EOF in keyword string\n");
> +			return token_error;
> +		}
> +		if (ch < 'a' || ch > 'z')
> +			break;
> +
> +		buffer[i] = ch;
> +		i++;
> +		if (i >= sizeof(buffer)) {
> +			fprintf(stderr, "json parser: keyword too long, maximum size %zd bytes\n", sizeof(buffer) - 1);
> +			return token_error;
> +		}
> +	}
> +	if (!strcmp(buffer, "true"))
> +		return token_true;
> +	if (!strcmp(buffer, "false"))
> +		return token_false;
> +	if (!strcmp(buffer, "null"))
> +		return token_null;
> +	return token_error;
> +}
> +
> +/*
> + *  json_get_token()
> + *	read next input character(s) and return a matching token
> + */
> +json_token_type json_get_token(json_file *jfile, json_token *token)
> +{
> +	(void)memset(token, 0, sizeof(*token));
> +
> +	token->offset = ftell(jfile->fp);
> +	for (;;) {
> +		int ch;
> +
> +		ch = fgetc(jfile->fp);
> +		jfile->charnum++;
> +
> +		switch (ch) {
> +		case '\n':
> +			jfile->linenum++;
> +			continue;
> +		case ' ':
> +		case '\r':
> +		case '\t':
> +			continue;
> +		case EOF:
> +			token->type = token_eof;
> +			return token->type;
> +		case '{':
> +			token->type = token_lbrace;
> +			return token->type;
> +		case '}':
> +			token->type = token_rbrace;
> +			return token->type;
> +		case '[':
> +			token->type = token_lbracket;
> +			return token->type;
> +		case ']':
> +			token->type = token_rbracket;
> +			return token->type;
> +		case ':':
> +			token->type = token_colon;
> +			return token->type;
> +		case ',':
> +			token->type = token_comma;
> +			return token->type;
> +		case '"':
> +			token->type = json_get_string(jfile, token);
> +			return token->type;
> +		case '0'...'9':
> +			token->type = json_get_int(jfile, token);
> +			return token->type;
> +		case 'a'...'z':
> +			fprintf(stderr, "json_parser: keywords not supported\n");
> +			token->type = token_error;
> +			return token->type;
> +		default:
> +			token->type = token_error;
> +			return token->type;
> +		}
> +	}
> +
> +	/* Should never reach here */
> +	token->type = token_error;
> +	return token->type;
> +}
> +
> +/*
> + *  json_parse_error_where()
> + *	very simple parser error message, report where in the file
> + *	the parsing error occurred.
> + */
> +void json_parse_error_where(json_file *jfile)
> +{
> +	if (jfile->error_reported == 0)
> +		fprintf(stderr, "json_parser: aborted at line %d, char %d of file %s\n",
> +			jfile->linenum, jfile->charnum, jfile->filename);
> +	jfile->error_reported++;
> +}
> +
> +json_object *json_parse_object(json_file *jfile);
> +
> +/*
> + *  json_parse_array()
> + *	parse a json array
> + */
> +json_object *json_parse_array(json_file *jfile)
> +{
> +	json_object *array_obj;
> +
> +	array_obj = json_object_new_array();
> +	if (!array_obj) {
> +		fprintf(stderr, "json_parser: out of memory allocating a json array object\n");
> +		json_parse_error_where(jfile);
> +		return NULL;
> +	}
> +
> +	for (;;) {
> +		json_object *obj;
> +		json_token token;
> +
> +		obj = json_parse_object(jfile);
> +		if (!obj) {
> +			json_parse_error_where(jfile);
> +			free(array_obj);
> +			return NULL;
> +		}
> +		json_object_array_add(array_obj, obj);
> +
> +		switch (json_get_token(jfile, &token)) {
> +		case token_rbracket:
> +			return array_obj;
> +		case token_comma:
> +			continue;
> +		default:
> +			if (json_unget_token(jfile, &token) != 0) {
> +				fprintf(stderr, "json_parser: failed to unget a token\n");
> +				free(array_obj);
> +				return NULL;
> +			}
> +			break;
> +		}
> +	}
> +	return array_obj;
> +}
> +
> +/*
> + *  json_parse_object()
> + *	parse a json object (simplified fwts json format only)
> + */
> +json_object *json_parse_object(json_file *jfile)
> +{
> +	json_token token;
> +	json_object *obj, *val_obj;
> +	char *key = NULL;
> +
> +	if (json_get_token(jfile, &token) != token_lbrace) {
> +		fprintf(stderr, "json_parser: expecting '{', got %s instead\n", json_token_string(&token));
> +		return NULL;
> +	}
> +
> +	obj = json_object_new_object();
> +	if (!obj)
> +		goto err_nomem;
> +
> +	for (;;) {
> +		switch (json_get_token(jfile, &token)) {
> +		case token_rbrace:
> +			return obj;
> +		case token_string:
> +			key = token.u.str;
> +			if (!key)
> +				goto err_nomem;
> +			token.u.str = NULL;
> +			break;
> +		default:
> +			fprintf(stderr, "json_parser: expecting } or key literal string, got %s instead\n", json_token_string(&token));
> +			goto err_free;
> +		}
> +		if (json_get_token(jfile, &token) != token_colon) {
> +			fprintf(stderr, "json_parser: expecting ':', got %s instead\n", json_token_string(&token));
> +			goto err_free;
> +		}
> +		switch (json_get_token(jfile, &token)) {
> +		case token_string:
> +			val_obj = json_object_new_string(token.u.str);
> +			if (!val_obj)
> +				goto err_nomem;
> +			json_object_object_add(obj, key, val_obj);
> +			free(key);
> +			break;
> +		case token_int:
> +			val_obj = json_object_new_int(token.u.intval);
> +			if (!val_obj)
> +				goto err_nomem;
> +			json_object_object_add(obj, key, val_obj);
> +			free(key);
> +			break;
> +		case token_lbracket:
> +			val_obj = json_parse_array(jfile);
> +			if (!val_obj)
> +				goto err_nomem;
> +			json_object_object_add(obj, key, val_obj);
> +			break;
> +		case token_lbrace:
> +			fprintf(stderr, "json_parser: nested objects not supported\n");
> +			goto err_free;
> +		case token_true:
> +		case token_false:
> +		case token_null:
> +			fprintf(stderr, "json_parser: tokens %s not supported\n", json_token_string(&token));
> +			goto err_free;
> +		default:
> +			fprintf(stderr, "json_parser: unexpected token %s\n", json_token_string(&token));
> +		}
> +		switch (json_get_token(jfile, &token)) {
> +		case token_comma:
> +			continue;
> +		case token_rbrace:
> +			return obj;
> +		default:
> +			fprintf(stderr, "json_parser: expected , or }, got %s instead\n", json_token_string(&token));
> +			goto err_free;
> +		}
> +	}
> +
> +err_nomem:
> +	fprintf(stderr, "json_parser: out of memory allocating a json object\n");
> +	json_parse_error_where(jfile);
> +err_free:
> +	free(obj);
> +	return NULL;
> +}
> +
> +/*
> + *  json_object_from_file()
> + *	parse a simplified fwts json file and convert it into
> + *	a json object, return NULL if parsing failed or ran
> + *	out of memory
> + */
> +json_object *json_object_from_file(const char *filename)
> +{
> +	json_object *obj;
> +	json_file jfile;
> +
> +	jfile.filename = filename;
> +	jfile.linenum = 1;
> +	jfile.charnum = 0;
> +	jfile.error_reported = 0;
> +
> +	jfile.fp = fopen(filename, "r");
> +	if (!jfile.fp)
> +		return NULL;
> +
> +	obj = json_parse_object(&jfile);
> +
> +	fclose(jfile.fp);
> +	return obj;
> +}
> +
> +/*
> + *  json_object_new_object()
> + *	return a new json object, NULL if failed
> + */
> +json_object *json_object_new_object(void)
> +{
> +	json_object *obj;
> +
> +	obj = calloc(1, sizeof(*obj));
> +	if (!obj)
> +		return NULL;
> +	obj->type = type_object;
> +	obj->u.ptr = NULL;
> +
> +	return obj;
> +}
> +
> +/*
> + *  json_object_new_object()
> + *	return a new json object, NULL if failed
> + */
> +int json_object_array_length(json_object *obj)
> +{
> +	if (!obj)
> +		return 0;
> +	if (obj->type != type_array)
> +		return 0;
> +	return obj->length;
> +}
> +
> +/*
> + *  json_object_new_int()
> + *	return a new json integer object, NULL if failed
> + */
> +json_object *json_object_new_int(int val)
> +{
> +	json_object *obj;
> +
> +	obj = calloc(1, sizeof(*obj));
> +	if (!obj)
> +		return NULL;
> +	obj->type = type_int;
> +	obj->u.intval = val;
> +
> +	return obj;
> +}
> +
> +/*
> + *  json_object_new_string()
> + *	return a new json string object, NULL if failed
> + */
> +json_object *json_object_new_string(const char *str)
> +{
> +	json_object *obj;
> +
> +	obj = calloc(1, sizeof(*obj));
> +	if (!obj)
> +		return NULL;
> +	obj->type = type_string;
> +	obj->u.ptr = strdup(str);
> +	if (!obj->u.ptr) {
> +		free(obj);
> +		return NULL;
> +	}
> +	return obj;
> +}
> +
> +/*
> + *  json_object_new_array()
> + *	return a new json array object, NULL if failed
> + */
> +json_object *json_object_new_array(void)
> +{
> +	json_object *obj;
> +
> +	obj = calloc(1, sizeof(*obj));
> +	if (!obj)
> +		return NULL;
> +	obj->type = type_array;
> +	obj->length = 0;
> +	obj->u.ptr = NULL;
> +
> +	return obj;
> +}
> +
> +/*
> + *  json_object_array_add_item()
> + *	add an object to another object, return 0 if succeeded,
> + *	non-zero if failed
> + */
> +static int json_object_array_add_item(json_object *obj, json_object *item)
> +{
> +	json_object **obj_ptr;
> +
> +	if (obj->length < 0)
> +		return -1;
> +	obj_ptr = realloc(obj->u.ptr, sizeof(json_object *) * (obj->length + 1));
> +	if (!obj_ptr)
> +		return -1;
> +	obj->u.ptr = (void *)obj_ptr;
> +	obj_ptr[obj->length] = item;
> +	obj->length++;
> +	return 0;
> +}
> +
> +/*
> + *  json_object_array_add()
> + *	add a object to a json array object, return NULL if failed
> + */
> +int json_object_array_add(json_object *obj, json_object *item)
> +{
> +	if (!obj || !item)
> +		return -1;
> +	if (obj->type != type_array)
> +		return -1;
> +	return json_object_array_add_item(obj, item);
> +}
> +
> +
> +/*
> + *  json_object_object_add()
> + *	add a key/valyue object to a json object, return NULL if failed
> + */
> +void json_object_object_add(json_object *obj, const char *key, json_object *value)
> +{
> +	if (!obj || !key || !value)
> +		return;
> +	if (obj->type != type_object)
> +		return;
> +	value->key = strdup(key);
> +	if (!value->key)
> +		return;
> +	json_object_array_add_item(obj, value);
> +}
> +
> +/*
> + *  json_object_array_get_idx()
> + *	get an object at position index from a json array object,
> + *	return NULL if failed
> + */
> +json_object *json_object_array_get_idx(json_object *obj, int index)
> +{
> +	json_object **obj_array;
> +
> +	if (!obj)
> +		return NULL;
> +	if (obj->type != type_array)
> +		return NULL;
> +	if (index >= obj->length)
> +		return NULL;
> +	obj_array = (json_object **)obj->u.ptr;
> +	if (obj_array == NULL)
> +		return NULL;
> +	return obj_array[index];
> +}
> +
> +/*
> + *  json_object_get_string()
> + *	return a C string from a json string object
> + */
> +const char *json_object_get_string(json_object *obj)
> +{
> +	if (!obj)
> +		return NULL;
> +	if (obj->type != type_string)
> +		return NULL;
> +	return (const char *)obj->u.ptr;
> +}
> +
> +/*
> + *  json_object_put()
> + *	free a json object and all sub-objects
> + */
> +void json_object_put(json_object *obj)
> +{
> +	int i;
> +	json_object **obj_ptr;
> +
> +	if (!obj)
> +		return;
> +
> +	if (obj->key)
> +		free(obj->key);
> +
> +	switch (obj->type) {
> +	case type_array:
> +	case type_object:
> +		obj_ptr = (json_object **)obj->u.ptr;
> +
> +		for (i = 0; i < obj->length; i++) {
> +			json_object_put(obj_ptr[i]);
> +		}
> +		free(obj->u.ptr);
> +		break;
> +	case type_string:
> +		free(obj->u.ptr);
> +		break;
> +	case type_null:
> +	case type_int:
> +	default:
> +		break;
> +	}
> +	free(obj);
> +}
> +
> +/*
> + *  str_append()
> + *	append a string to a string, return NULL if failed
> + */
> +static char *str_append(char *str, char *append)
> +{
> +	char *new_str;
> +	size_t len;
> +
> +	if (!append)
> +		return NULL;
> +
> +	if (str) {
> +		len = strlen(append) + strlen(str) + 1;
> +		new_str = realloc(str, len);
> +		if (!new_str) {
> +			free(str);
> +			return NULL;
> +		}
> +		strcat(new_str, append);
> +	} else {
> +		len = strlen(append) + 1;
> +		new_str = malloc(len);
> +		if (!new_str)
> +			return NULL;
> +		strcpy(new_str, append);
> +	}
> +	return new_str;
> +}
> +
> +/*
> + *  str_indent()
> + *	add 2 spaces per indent level to a string, returns
> + *	NULL if failed
> + */
> +static char *str_indent(char *str, int indent)
> +{
> +	char buf[81];
> +	int i;
> +
> +	indent = indent + indent;
> +	if (indent > 80)
> +		indent = 80;
> +
> +	for (i = 0; i < indent; i++)
> +		buf[i] = ' ';
> +	buf[i] = '\0';
> +
> +	return str_append(str, buf);
> +}
> +
> +/*
> + *  json_object_to_json_string_indent()
> + *	turn a simplified fwts json object into a C string, returns
> + *	the stringified object or NULL if failed. Will traverse object
> + *	tree and add indentation based on recursion depth.
> + */
> +static char *json_object_to_json_string_indent(json_object *obj, int indent)
> +{
> +	int i;
> +	json_object **obj_ptr;
> +	char *str = NULL;
> +	char buf[64];
> +
> +	if (!obj)
> +		return NULL;
> +
> +	if (obj->type == type_object) {
> +		str = str_indent(str, indent);
> +		if (!str)
> +			return NULL;
> +		str = str_append(str, "{\n");
> +		if (!str)
> +			return NULL;
> +	}
> +
> +        if (obj->key) {
> +		str = str_indent(str, indent);
> +		if (!str)
> +			return NULL;
> +		str = str_append(str, "\"");
> +		if (!str)
> +			return NULL;
> +		str = str_append(str, obj->key);
> +		if (!str)
> +			return NULL;
> +		str = str_append(str, "\":");
> +		if (!str)
> +			return NULL;
> +        }
> +
> +	switch (obj->type) {
> +	case type_array:
> +		str = str_append(str, "[\n");
> +		if (!str)
> +			return NULL;
> +
> +		obj_ptr = (json_object **)obj->u.ptr;
> +		if (obj_ptr) {
> +			for (i = 0; i < obj->length; i++) {
> +				char *obj_str = json_object_to_json_string_indent(obj_ptr[i], indent + 1);
> +
> +				if (!obj_str) {
> +					free(str);
> +					return NULL;
> +				}
> +				str = str_append(str, obj_str);
> +				if (!str)
> +					return NULL;
> +			}
> +		}
> +		str = str_append(str, "\n");
> +		if (!str)
> +			return NULL;
> +		str = str_indent(str, indent);
> +		if (!str)
> +			return NULL;
> +		str = str_append(str, "]\n");
> +		if (!str)
> +			return NULL;
> +		break;
> +
> +	case type_object:
> +		obj_ptr = (json_object **)obj->u.ptr;
> +		if (obj_ptr) {
> +			for (i = 0; i < obj->length; i++) {
> +				char *obj_str = json_object_to_json_string_indent(obj_ptr[i], indent + 1);
> +
> +				if (!obj_str)
> +					return NULL;
> +				str = str_append(str, obj_str);
> +				if (!str)
> +					return NULL;
> +			}
> +		}
> +		if (!str)
> +			return NULL;
> +		break;
> +
> +	case type_string:
> +		str = str_append(str, "\"");
> +		if (!str)
> +			return NULL;
> +		str = str_append(str, (char *)obj->u.ptr);
> +		if (!str)
> +			return NULL;
> +		str = str_append(str, "\",\n");
> +		if (!str)
> +			return NULL;
> +		break;
> +
> +	case type_null:
> +		str = str_append(str, "(null)\n");
> +		if (!str)
> +			return NULL;
> +		break;
> +
> +	case type_int:
> +		snprintf(buf, sizeof(buf), "%d,\n", obj->u.intval);
> +		str = str_append(str, buf);
> +		if (!str)
> +			return NULL;
> +		break;
> +	default:
> +		return NULL;
> +	}
> +
> +	if (obj->type == type_object) {
> +		str = str_indent(str, indent);
> +		if (!str)
> +			return NULL;
> +		str = str_append(str, "},\n");
> +		if (!str)
> +			return NULL;
> +	}
> +	return str;
> +}
> +
> +/*
> + *  json_object_to_json_string
> + *	convert simplified fwts object to a C string, returns
> + *	NULL if failed
> + */
> +char *json_object_to_json_string(json_object *obj)
> +{
> +	return json_object_to_json_string_indent(obj, 0);
> +}
> +
> +/*
> + *  json_object_object_get()
> + *	return value from key/value pair from an object, returns
> + *	NULL if it can't be found
> + */
> +json_object *json_object_object_get(json_object *obj, const char *key)
> +{
> +	int i;
> +	json_object **obj_ptr;
> +
> +	if (!obj || !key)
> +		return NULL;
> +	if (obj->type != type_object)
> +		return NULL;
> +
> +	obj_ptr = (json_object **)obj->u.ptr;
> +	for (i = 0; i < obj->length; i++) {
> +		if (obj_ptr[i]->key && !strcmp(obj_ptr[i]->key, key))
> +			return obj_ptr[i];
> +	}
> +	return NULL;
> +}
> +
> diff --git a/src/utilities/Makefile.am b/src/utilities/Makefile.am
> index 98d6ebaa..2ae86038 100644
> --- a/src/utilities/Makefile.am
> +++ b/src/utilities/Makefile.am
> @@ -18,10 +18,11 @@
>  
>  AM_CPPFLAGS = -Wall -Werror -Wextra -DDATAROOTDIR=\"$(datarootdir)\" \
>  	`pkg-config --silence-errors --cflags json` \
> -	`pkg-config --silence-errors --cflags json-c`
> +	`pkg-config --silence-errors --cflags json-c` \
> +	-I../lib/include
>  
>  bin_PROGRAMS = kernelscan
> -kernelscan_SOURCES = kernelscan.c
> +kernelscan_SOURCES = kernelscan.c ../lib/src/fwts_json.c
>  
>  
>  -include $(top_srcdir)/git.mk
> diff --git a/src/utilities/kernelscan.c b/src/utilities/kernelscan.c
> index 2e68ef33..49ffe5c1 100644
> --- a/src/utilities/kernelscan.c
> +++ b/src/utilities/kernelscan.c
> @@ -21,11 +21,12 @@
>  #include <stdbool.h>
>  #include <stdlib.h>
>  #include <string.h>
> +#include <stddef.h>
>  #include <ctype.h>
>  #include <unistd.h>
>  #include <sys/types.h>
>  #include <regex.h>
> -#include <json.h>
> +#include "fwts_json.h"
>  
>  #include "config.h"
>  
> 

Acked-by: Ivan Hu <ivan.hu at canonical.com>



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