163 lines
3.9 KiB
C
163 lines
3.9 KiB
C
/* Parse JSON files using the JSMN parser. */
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/*
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* Copyright (c) 2014, Intel Corporation
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
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* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <stdlib.h>
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#include <string.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <errno.h>
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#include <unistd.h>
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#include "jsmn.h"
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#include "json.h"
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#include <linux/kernel.h>
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static char *mapfile(const char *fn, size_t *size)
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{
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unsigned ps = sysconf(_SC_PAGESIZE);
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struct stat st;
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char *map = NULL;
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int err;
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int fd = open(fn, O_RDONLY);
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if (fd < 0 && verbose && fn) {
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pr_err("Error opening events file '%s': %s\n", fn,
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strerror(errno));
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}
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if (fd < 0)
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return NULL;
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err = fstat(fd, &st);
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if (err < 0)
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goto out;
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*size = st.st_size;
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map = mmap(NULL,
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(st.st_size + ps - 1) & ~(ps - 1),
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PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
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if (map == MAP_FAILED)
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map = NULL;
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out:
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close(fd);
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return map;
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}
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static void unmapfile(char *map, size_t size)
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{
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unsigned ps = sysconf(_SC_PAGESIZE);
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munmap(map, roundup(size, ps));
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}
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/*
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* Parse json file using jsmn. Return array of tokens,
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* and mapped file. Caller needs to free array.
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*/
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jsmntok_t *parse_json(const char *fn, char **map, size_t *size, int *len)
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{
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jsmn_parser parser;
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jsmntok_t *tokens;
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jsmnerr_t res;
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unsigned sz;
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*map = mapfile(fn, size);
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if (!*map)
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return NULL;
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/* Heuristic */
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sz = *size * 16;
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tokens = malloc(sz);
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if (!tokens)
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goto error;
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jsmn_init(&parser);
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res = jsmn_parse(&parser, *map, *size, tokens,
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sz / sizeof(jsmntok_t));
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if (res != JSMN_SUCCESS) {
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pr_err("%s: json error %s\n", fn, jsmn_strerror(res));
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goto error_free;
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}
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if (len)
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*len = parser.toknext;
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return tokens;
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error_free:
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free(tokens);
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error:
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unmapfile(*map, *size);
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return NULL;
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}
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void free_json(char *map, size_t size, jsmntok_t *tokens)
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{
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free(tokens);
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unmapfile(map, size);
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}
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static int countchar(char *map, char c, int end)
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{
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int i;
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int count = 0;
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for (i = 0; i < end; i++)
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if (map[i] == c)
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count++;
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return count;
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}
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/* Return line number of a jsmn token */
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int json_line(char *map, jsmntok_t *t)
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{
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return countchar(map, '\n', t->start) + 1;
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}
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static const char * const jsmn_types[] = {
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[JSMN_PRIMITIVE] = "primitive",
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[JSMN_ARRAY] = "array",
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[JSMN_OBJECT] = "object",
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[JSMN_STRING] = "string"
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};
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#define LOOKUP(a, i) ((i) < (sizeof(a)/sizeof(*(a))) ? ((a)[i]) : "?")
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/* Return type name of a jsmn token */
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const char *json_name(jsmntok_t *t)
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{
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return LOOKUP(jsmn_types, t->type);
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}
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int json_len(jsmntok_t *t)
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{
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return t->end - t->start;
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}
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/* Is string t equal to s? */
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int json_streq(char *map, jsmntok_t *t, const char *s)
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{
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unsigned len = json_len(t);
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return len == strlen(s) && !strncasecmp(map + t->start, s, len);
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}
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