iproute2/lib/json_writer.c
Andrea Claudi 49c63bc775 json: do not escape single quotes
ECMA-404 standard does not include single quote character among the json
escape sequences. This means single quotes does not need to be escaped.

Indeed the single quote escape produces an invalid json output:

$ ip link add "john's" type dummy
$ ip link show "john's"
9: john's: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/ether c6:8e:53:f6:a3:4b brd ff:ff:ff:ff:ff:ff
$ ip -j link | jq .
parse error: Invalid escape at line 1, column 765

This can be fixed removing the single quote escape in jsonw_puts.
With this patch in place:

$ ip -j link | jq .[].ifname
"lo"
"john's"

Fixes: fcc16c2287bf ("provide common json output formatter")
Signed-off-by: Andrea Claudi <aclaudi@redhat.com>
2022-11-03 11:30:20 -07:00

387 lines
7.3 KiB
C

/* SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) */
/*
* Simple streaming JSON writer
*
* This takes care of the annoying bits of JSON syntax like the commas
* after elements
*
* Authors: Stephen Hemminger <stephen@networkplumber.org>
*/
#include <stdio.h>
#include <stdbool.h>
#include <stdarg.h>
#include <assert.h>
#include <malloc.h>
#include <inttypes.h>
#include <stdint.h>
#include "json_writer.h"
struct json_writer {
FILE *out; /* output file */
unsigned depth; /* nesting */
bool pretty; /* optional whitepace */
char sep; /* either nul or comma */
};
/* indentation for pretty print */
static void jsonw_indent(json_writer_t *self)
{
unsigned i;
for (i = 0; i < self->depth; ++i)
fputs(" ", self->out);
}
/* end current line and indent if pretty printing */
static void jsonw_eol(json_writer_t *self)
{
if (!self->pretty)
return;
putc('\n', self->out);
jsonw_indent(self);
}
/* If current object is not empty print a comma */
static void jsonw_eor(json_writer_t *self)
{
if (self->sep != '\0')
putc(self->sep, self->out);
self->sep = ',';
}
/* Output JSON encoded string */
/* Handles C escapes, does not do Unicode */
static void jsonw_puts(json_writer_t *self, const char *str)
{
putc('"', self->out);
for (; *str; ++str)
switch (*str) {
case '\t':
fputs("\\t", self->out);
break;
case '\n':
fputs("\\n", self->out);
break;
case '\r':
fputs("\\r", self->out);
break;
case '\f':
fputs("\\f", self->out);
break;
case '\b':
fputs("\\b", self->out);
break;
case '\\':
fputs("\\\\", self->out);
break;
case '"':
fputs("\\\"", self->out);
break;
default:
putc(*str, self->out);
}
putc('"', self->out);
}
/* Create a new JSON stream */
json_writer_t *jsonw_new(FILE *f)
{
json_writer_t *self = malloc(sizeof(*self));
if (self) {
self->out = f;
self->depth = 0;
self->pretty = false;
self->sep = '\0';
}
return self;
}
/* End output to JSON stream */
void jsonw_destroy(json_writer_t **self_p)
{
json_writer_t *self = *self_p;
assert(self->depth == 0);
fputs("\n", self->out);
fflush(self->out);
free(self);
*self_p = NULL;
}
void jsonw_pretty(json_writer_t *self, bool on)
{
self->pretty = on;
}
/* Basic blocks */
static void jsonw_begin(json_writer_t *self, int c)
{
jsonw_eor(self);
putc(c, self->out);
++self->depth;
self->sep = '\0';
}
static void jsonw_end(json_writer_t *self, int c)
{
assert(self->depth > 0);
--self->depth;
if (self->sep != '\0')
jsonw_eol(self);
putc(c, self->out);
self->sep = ',';
}
/* Add a JSON property name */
void jsonw_name(json_writer_t *self, const char *name)
{
jsonw_eor(self);
jsonw_eol(self);
self->sep = '\0';
jsonw_puts(self, name);
putc(':', self->out);
if (self->pretty)
putc(' ', self->out);
}
__attribute__((format(printf, 2, 3)))
void jsonw_printf(json_writer_t *self, const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
jsonw_eor(self);
vfprintf(self->out, fmt, ap);
va_end(ap);
}
/* Collections */
void jsonw_start_object(json_writer_t *self)
{
jsonw_begin(self, '{');
}
void jsonw_end_object(json_writer_t *self)
{
jsonw_end(self, '}');
}
void jsonw_start_array(json_writer_t *self)
{
jsonw_begin(self, '[');
if (self->pretty)
putc(' ', self->out);
}
void jsonw_end_array(json_writer_t *self)
{
if (self->pretty && self->sep)
putc(' ', self->out);
self->sep = '\0';
jsonw_end(self, ']');
}
/* JSON value types */
void jsonw_string(json_writer_t *self, const char *value)
{
jsonw_eor(self);
jsonw_puts(self, value);
}
void jsonw_bool(json_writer_t *self, bool val)
{
jsonw_printf(self, "%s", val ? "true" : "false");
}
void jsonw_null(json_writer_t *self)
{
jsonw_printf(self, "null");
}
void jsonw_float(json_writer_t *self, double num)
{
jsonw_printf(self, "%g", num);
}
void jsonw_hhu(json_writer_t *self, unsigned char num)
{
jsonw_printf(self, "%hhu", num);
}
void jsonw_hu(json_writer_t *self, unsigned short num)
{
jsonw_printf(self, "%hu", num);
}
void jsonw_uint(json_writer_t *self, unsigned int num)
{
jsonw_printf(self, "%u", num);
}
void jsonw_u64(json_writer_t *self, uint64_t num)
{
jsonw_printf(self, "%"PRIu64, num);
}
void jsonw_xint(json_writer_t *self, uint64_t num)
{
jsonw_printf(self, "%"PRIx64, num);
}
void jsonw_luint(json_writer_t *self, unsigned long num)
{
jsonw_printf(self, "%lu", num);
}
void jsonw_lluint(json_writer_t *self, unsigned long long num)
{
jsonw_printf(self, "%llu", num);
}
void jsonw_int(json_writer_t *self, int num)
{
jsonw_printf(self, "%d", num);
}
void jsonw_s64(json_writer_t *self, int64_t num)
{
jsonw_printf(self, "%"PRId64, num);
}
/* Basic name/value objects */
void jsonw_string_field(json_writer_t *self, const char *prop, const char *val)
{
jsonw_name(self, prop);
jsonw_string(self, val);
}
void jsonw_bool_field(json_writer_t *self, const char *prop, bool val)
{
jsonw_name(self, prop);
jsonw_bool(self, val);
}
void jsonw_float_field(json_writer_t *self, const char *prop, double val)
{
jsonw_name(self, prop);
jsonw_float(self, val);
}
void jsonw_uint_field(json_writer_t *self, const char *prop, unsigned int num)
{
jsonw_name(self, prop);
jsonw_uint(self, num);
}
void jsonw_u64_field(json_writer_t *self, const char *prop, uint64_t num)
{
jsonw_name(self, prop);
jsonw_u64(self, num);
}
void jsonw_xint_field(json_writer_t *self, const char *prop, uint64_t num)
{
jsonw_name(self, prop);
jsonw_xint(self, num);
}
void jsonw_hhu_field(json_writer_t *self, const char *prop, unsigned char num)
{
jsonw_name(self, prop);
jsonw_hhu(self, num);
}
void jsonw_hu_field(json_writer_t *self, const char *prop, unsigned short num)
{
jsonw_name(self, prop);
jsonw_hu(self, num);
}
void jsonw_luint_field(json_writer_t *self,
const char *prop,
unsigned long num)
{
jsonw_name(self, prop);
jsonw_luint(self, num);
}
void jsonw_lluint_field(json_writer_t *self,
const char *prop,
unsigned long long num)
{
jsonw_name(self, prop);
jsonw_lluint(self, num);
}
void jsonw_int_field(json_writer_t *self, const char *prop, int num)
{
jsonw_name(self, prop);
jsonw_int(self, num);
}
void jsonw_s64_field(json_writer_t *self, const char *prop, int64_t num)
{
jsonw_name(self, prop);
jsonw_s64(self, num);
}
void jsonw_null_field(json_writer_t *self, const char *prop)
{
jsonw_name(self, prop);
jsonw_null(self);
}
#ifdef TEST
int main(int argc, char **argv)
{
json_writer_t *wr = jsonw_new(stdout);
jsonw_start_object(wr);
jsonw_pretty(wr, true);
jsonw_name(wr, "Vyatta");
jsonw_start_object(wr);
jsonw_string_field(wr, "url", "http://vyatta.com");
jsonw_uint_field(wr, "downloads", 2000000ul);
jsonw_float_field(wr, "stock", 8.16);
jsonw_name(wr, "ARGV");
jsonw_start_array(wr);
while (--argc)
jsonw_string(wr, *++argv);
jsonw_end_array(wr);
jsonw_name(wr, "empty");
jsonw_start_array(wr);
jsonw_end_array(wr);
jsonw_name(wr, "NIL");
jsonw_start_object(wr);
jsonw_end_object(wr);
jsonw_null_field(wr, "my_null");
jsonw_name(wr, "special chars");
jsonw_start_array(wr);
jsonw_string_field(wr, "slash", "/");
jsonw_string_field(wr, "newline", "\n");
jsonw_string_field(wr, "tab", "\t");
jsonw_string_field(wr, "ff", "\f");
jsonw_string_field(wr, "quote", "\"");
jsonw_string_field(wr, "tick", "\'");
jsonw_string_field(wr, "backslash", "\\");
jsonw_end_array(wr);
jsonw_end_object(wr);
jsonw_end_object(wr);
jsonw_destroy(&wr);
return 0;
}
#endif