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json_util.c
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json_util.c
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/*
* Copyright (c) 2004, 2005 Metaparadigm Pte. Ltd.
* Michael Clark <michael@metaparadigm.com>
* Copyright (c) 2016 Adiscon GmbH
* Rainer Gerhards <rgerhards@adiscon.com>
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the MIT license. See COPYING for details.
*
*/
#include "config.h"
#undef realloc
#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <limits.h>
#include <string.h>
#include <errno.h>
#include <ctype.h>
#include <stdint.h>
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif /* HAVE_SYS_TYPES_H */
#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif /* HAVE_SYS_STAT_H */
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif /* HAVE_FCNTL_H */
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif /* HAVE_UNISTD_H */
#if !defined(HAVE_SNPRINTF)
# error You do not have snprintf on your system.
#endif /* HAVE_SNPRINTF */
#include "debug.h"
#include "printbuf.h"
#include "json_object.h"
#include "json_tokener.h"
#include "json_util.h"
static int sscanf_is_broken = 0;
static int sscanf_is_broken_testdone = 0;
static void sscanf_is_broken_test(void);
/*
* Create a JSON object from already opened file descriptor.
*
* This function can be helpful, when you opened the file already,
* e.g. when you have a temp file.
* Note, that the fd must be readable at the actual position, i.e.
* use lseek(fd, 0, SEEK_SET) before.
*/
struct fjson_object* fjson_object_from_fd(int fd)
{
struct printbuf *pb;
struct fjson_object *obj;
char buf[FJSON_FILE_BUF_SIZE];
int ret;
if(!(pb = printbuf_new())) {
MC_ERROR("fjson_object_from_file: printbuf_new failed\n");
return NULL;
}
while((ret = read(fd, buf, FJSON_FILE_BUF_SIZE)) > 0) {
printbuf_memappend(pb, buf, ret);
}
if(ret < 0) {
MC_ERROR("fjson_object_from_fd: error reading fd %d: %s\n", fd, strerror(errno));
printbuf_free(pb);
return NULL;
}
obj = fjson_tokener_parse(pb->buf);
printbuf_free(pb);
return obj;
}
struct fjson_object* fjson_object_from_file(const char *filename)
{
struct fjson_object *obj;
int fd;
if((fd = open(filename, O_RDONLY)) < 0) {
MC_ERROR("fjson_object_from_file: error opening file %s: %s\n",
filename, strerror(errno));
return NULL;
}
obj = fjson_object_from_fd(fd);
close(fd);
return obj;
}
/* extended "format and write to file" function */
int fjson_object_to_file_ext(const char *filename, struct fjson_object *obj, int flags)
{
const char *fjson_str;
int fd, ret;
unsigned int wpos, wsize;
if(!obj) {
MC_ERROR("fjson_object_to_file: object is null\n");
return -1;
}
if((fd = open(filename, O_WRONLY | O_TRUNC | O_CREAT, 0644)) < 0) {
MC_ERROR("fjson_object_to_file: error opening file %s: %s\n",
filename, strerror(errno));
return -1;
}
if(!(fjson_str = fjson_object_to_json_string_ext(obj,flags))) {
close(fd);
return -1;
}
wsize = (unsigned int)(strlen(fjson_str) & UINT_MAX); /* CAW: probably unnecessary, but the most 64bit safe */
wpos = 0;
while(wpos < wsize) {
if((ret = write(fd, fjson_str + wpos, wsize-wpos)) < 0) {
close(fd);
MC_ERROR("fjson_object_to_file: error writing file %s: %s\n",
filename, strerror(errno));
return -1;
}
/* because of the above check for ret < 0, we can safely cast and add */
wpos += (unsigned int)ret;
}
close(fd);
return 0;
}
// backwards compatible "format and write to file" function
int fjson_object_to_file(const char *filename, struct fjson_object *obj)
{
return fjson_object_to_file_ext(filename, obj, FJSON_TO_STRING_PLAIN);
}
int fjson_parse_double(const char *buf, double *retval)
{
return (sscanf(buf, "%lf", retval)==1 ? 0 : 1);
}
/*
* Not all implementations of sscanf actually work properly.
* Check whether the one we're currently using does, and if
* it's broken, enable the workaround code.
*/
static void sscanf_is_broken_test(void)
{
int64_t num64;
int ret_errno, is_int64_min, ret_errno2, is_int64_max;
(void)sscanf(" -01234567890123456789012345", "%" SCNd64, &num64);
ret_errno = errno;
is_int64_min = (num64 == INT64_MIN);
(void)sscanf(" 01234567890123456789012345", "%" SCNd64, &num64);
ret_errno2 = errno;
is_int64_max = (num64 == INT64_MAX);
if (ret_errno != ERANGE || !is_int64_min ||
ret_errno2 != ERANGE || !is_int64_max)
{
MC_DEBUG("sscanf_is_broken_test failed, enabling workaround code\n");
sscanf_is_broken = 1;
}
}
int fjson_parse_int64(const char *buf, int64_t *retval)
{
int64_t num64;
const char *buf_sig_digits;
int orig_has_neg;
int saved_errno;
if (!sscanf_is_broken_testdone)
{
sscanf_is_broken_test();
sscanf_is_broken_testdone = 1;
}
// Skip leading spaces
while (isspace((int)*buf) && *buf)
buf++;
errno = 0; // sscanf won't always set errno, so initialize
if (sscanf(buf, "%" SCNd64, &num64) != 1)
{
MC_DEBUG("Failed to parse, sscanf != 1\n");
return 1;
}
saved_errno = errno;
buf_sig_digits = buf;
orig_has_neg = 0;
if (*buf_sig_digits == '-')
{
buf_sig_digits++;
orig_has_neg = 1;
}
// Not all sscanf implementations actually work
if (sscanf_is_broken && saved_errno != ERANGE)
{
char buf_cmp[100];
char *buf_cmp_start = buf_cmp;
int recheck_has_neg = 0;
int buf_cmp_len;
// Skip leading zeros, but keep at least one digit
while (buf_sig_digits[0] == '0' && buf_sig_digits[1] != '\0')
buf_sig_digits++;
if (num64 == 0) // assume all sscanf impl's will parse -0 to 0
orig_has_neg = 0; // "-0" is the same as just plain "0"
snprintf(buf_cmp_start, sizeof(buf_cmp), "%" PRId64, num64);
if (*buf_cmp_start == '-')
{
recheck_has_neg = 1;
buf_cmp_start++;
}
// No need to skip leading spaces or zeros here.
buf_cmp_len = strlen(buf_cmp_start);
/**
* If the sign is different, or
* some of the digits are different, or
* there is another digit present in the original string
* then we have NOT successfully parsed the value.
*/
if (orig_has_neg != recheck_has_neg ||
strncmp(buf_sig_digits, buf_cmp_start, strlen(buf_cmp_start)) != 0 ||
((int)strlen(buf_sig_digits) != buf_cmp_len &&
isdigit((int)buf_sig_digits[buf_cmp_len])
)
)
{
saved_errno = ERANGE;
}
}
// Not all sscanf impl's set the value properly when out of range.
// Always do this, even for properly functioning implementations,
// since it shouldn't slow things down much.
if (saved_errno == ERANGE)
{
if (orig_has_neg)
num64 = INT64_MIN;
else
num64 = INT64_MAX;
}
*retval = num64;
return 0;
}
#define NELEM(a) (sizeof(a) / sizeof(a[0]))
static const char* fjson_type_name[] = {
/* If you change this, be sure to update the enum fjson_type definition too */
"null",
"boolean",
"double",
"int",
"object",
"array",
"string",
};
const char *fjson_type_to_name(enum fjson_type o_type)
{
int o_type_int = (int)o_type;
if (o_type_int < 0 || o_type_int >= (int)NELEM(fjson_type_name))
{
MC_ERROR("fjson_type_to_name: type %d is out of range [0,%zu]\n", o_type, NELEM(fjson_type_name));
return NULL;
}
return fjson_type_name[o_type];
}