libubox/jshn.c
Christian Beier 9c4aeda962 jshn: add functionality to read big JSON
The existing read functionality feeds the complete JSON to jshn as a
cmdline argument, leading to `-ash: jshn: Argument list too long`
errors for JSONs bigger than ca. 100KB.

This commit adds the ability to read the JSON directly from a file if
wanted, removing this shell-imposed size limit.

Tested on x86-64 and ar71xx. An mmap()-based solution was also evaluated,
but found to make no performance difference on either platform.

Signed-off-by: Christian Beier <dontmind@freeshell.org>
2018-01-22 09:21:03 +01:00

414 lines
8.6 KiB
C

/*
* Copyright (C) 2011-2013 Felix Fietkau <nbd@openwrt.org>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#ifdef JSONC
#include <json.h>
#else
#include <json/json.h>
#endif
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdbool.h>
#include <ctype.h>
#include <getopt.h>
#include <sys/stat.h>
#include <fcntl.h>
#include "list.h"
#include "avl.h"
#include "blob.h"
#include "blobmsg_json.h"
#define MAX_VARLEN 256
static struct avl_tree env_vars;
static struct blob_buf b = { 0 };
static const char *var_prefix = "";
static int var_prefix_len = 0;
static int add_json_element(const char *key, json_object *obj);
struct env_var {
struct avl_node avl;
char *val;
};
static int add_json_object(json_object *obj)
{
int ret = 0;
json_object_object_foreach(obj, key, val) {
ret = add_json_element(key, val);
if (ret)
break;
}
return ret;
}
static int add_json_array(struct array_list *a)
{
char seq[12];
int i, len;
int ret;
for (i = 0, len = array_list_length(a); i < len; i++) {
sprintf(seq, "%d", i);
ret = add_json_element(seq, array_list_get_idx(a, i));
if (ret)
return ret;
}
return 0;
}
static void add_json_string(const char *str)
{
char *ptr = (char *) str;
int len;
char *c;
while ((c = strchr(ptr, '\'')) != NULL) {
len = c - ptr;
if (len > 0)
fwrite(ptr, len, 1, stdout);
ptr = c + 1;
c = "'\\''";
fwrite(c, strlen(c), 1, stdout);
}
len = strlen(ptr);
if (len > 0)
fwrite(ptr, len, 1, stdout);
}
static void write_key_string(const char *key)
{
while (*key) {
putc(isalnum(*key) ? *key : '_', stdout);
key++;
}
}
static int add_json_element(const char *key, json_object *obj)
{
char *type;
switch (json_object_get_type(obj)) {
case json_type_object:
type = "object";
break;
case json_type_array:
type = "array";
break;
case json_type_string:
type = "string";
break;
case json_type_boolean:
type = "boolean";
break;
case json_type_int:
type = "int";
break;
case json_type_double:
type = "double";
break;
case json_type_null:
type = "null";
break;
default:
return -1;
}
fprintf(stdout, "json_add_%s '", type);
write_key_string(key);
switch (json_object_get_type(obj)) {
case json_type_object:
fprintf(stdout, "';\n");
add_json_object(obj);
fprintf(stdout, "json_close_object;\n");
break;
case json_type_array:
fprintf(stdout, "';\n");
add_json_array(json_object_get_array(obj));
fprintf(stdout, "json_close_array;\n");
break;
case json_type_string:
fprintf(stdout, "' '");
add_json_string(json_object_get_string(obj));
fprintf(stdout, "';\n");
break;
case json_type_boolean:
fprintf(stdout, "' %d;\n", json_object_get_boolean(obj));
break;
case json_type_int:
fprintf(stdout, "' %jd;\n", json_object_get_int64(obj));
break;
case json_type_double:
fprintf(stdout, "' %lf;\n", json_object_get_double(obj));
break;
case json_type_null:
fprintf(stdout, "';\n");
break;
default:
return -1;
}
return 0;
}
static int jshn_parse(const char *str)
{
json_object *obj;
obj = json_tokener_parse(str);
if (!obj || json_object_get_type(obj) != json_type_object) {
fprintf(stderr, "Failed to parse message data\n");
return 1;
}
fprintf(stdout, "json_init;\n");
add_json_object(obj);
fflush(stdout);
return 0;
}
static char *getenv_avl(const char *key)
{
struct env_var *var = avl_find_element(&env_vars, key, var, avl);
return var ? var->val : NULL;
}
static char *get_keys(const char *prefix)
{
char *keys;
keys = alloca(var_prefix_len + strlen(prefix) + sizeof("K_") + 1);
sprintf(keys, "%sK_%s", var_prefix, prefix);
return getenv_avl(keys);
}
static void get_var(const char *prefix, const char **name, char **var, char **type)
{
char *tmpname, *varname;
tmpname = alloca(var_prefix_len + strlen(prefix) + 1 + strlen(*name) + 1 + sizeof("T_"));
sprintf(tmpname, "%s%s_%s", var_prefix, prefix, *name);
*var = getenv_avl(tmpname);
sprintf(tmpname, "%sT_%s_%s", var_prefix, prefix, *name);
*type = getenv_avl(tmpname);
sprintf(tmpname, "%sN_%s_%s", var_prefix, prefix, *name);
varname = getenv_avl(tmpname);
if (varname)
*name = varname;
}
static json_object *jshn_add_objects(json_object *obj, const char *prefix, bool array);
static void jshn_add_object_var(json_object *obj, bool array, const char *prefix, const char *name)
{
json_object *new;
char *var, *type;
get_var(prefix, &name, &var, &type);
if (!var || !type)
return;
if (!strcmp(type, "array")) {
new = json_object_new_array();
jshn_add_objects(new, var, true);
} else if (!strcmp(type, "object")) {
new = json_object_new_object();
jshn_add_objects(new, var, false);
} else if (!strcmp(type, "string")) {
new = json_object_new_string(var);
} else if (!strcmp(type, "int")) {
new = json_object_new_int64(atoll(var));
} else if (!strcmp(type, "double")) {
new = json_object_new_double(strtod(var, NULL));
} else if (!strcmp(type, "boolean")) {
new = json_object_new_boolean(!!atoi(var));
} else if (!strcmp(type, "null")) {
new = NULL;
} else {
return;
}
if (array)
json_object_array_add(obj, new);
else
json_object_object_add(obj, name, new);
}
static json_object *jshn_add_objects(json_object *obj, const char *prefix, bool array)
{
char *keys, *key, *brk;
keys = get_keys(prefix);
if (!keys || !obj)
goto out;
for (key = strtok_r(keys, " ", &brk); key;
key = strtok_r(NULL, " ", &brk)) {
jshn_add_object_var(obj, array, prefix, key);
}
out:
return obj;
}
static int jshn_format(bool no_newline, bool indent)
{
json_object *obj;
const char *output;
char *blobmsg_output = NULL;
int ret = -1;
if (!(obj = json_object_new_object()))
return -1;
jshn_add_objects(obj, "J_V", false);
if (!(output = json_object_to_json_string(obj)))
goto out;
if (indent) {
blob_buf_init(&b, 0);
if (!blobmsg_add_json_from_string(&b, output))
goto out;
if (!(blobmsg_output = blobmsg_format_json_indent(b.head, 1, 0)))
goto out;
output = blobmsg_output;
}
fprintf(stdout, "%s%s", output, no_newline ? "" : "\n");
free(blobmsg_output);
ret = 0;
out:
json_object_put(obj);
return ret;
}
static int usage(const char *progname)
{
fprintf(stderr, "Usage: %s [-n] [-i] -r <message>|-R <file>|-w\n", progname);
return 2;
}
static int avl_strcmp_var(const void *k1, const void *k2, void *ptr)
{
const char *s1 = k1;
const char *s2 = k2;
char c1, c2;
while (*s1 && *s1 == *s2) {
s1++;
s2++;
}
c1 = *s1;
c2 = *s2;
if (c1 == '=')
c1 = 0;
if (c2 == '=')
c2 = 0;
return c1 - c2;
}
int main(int argc, char **argv)
{
extern char **environ;
bool no_newline = false;
bool indent = false;
struct env_var *vars;
int i;
int ch;
int fd;
struct stat sb;
char *fbuf;
int ret;
avl_init(&env_vars, avl_strcmp_var, false, NULL);
for (i = 0; environ[i]; i++);
vars = calloc(i, sizeof(*vars));
if (!vars) {
fprintf(stderr, "%m\n");
return -1;
}
for (i = 0; environ[i]; i++) {
char *c;
vars[i].avl.key = environ[i];
c = strchr(environ[i], '=');
if (!c)
continue;
vars[i].val = c + 1;
avl_insert(&env_vars, &vars[i].avl);
}
while ((ch = getopt(argc, argv, "p:nir:R:w")) != -1) {
switch(ch) {
case 'p':
var_prefix = optarg;
var_prefix_len = strlen(var_prefix);
break;
case 'r':
return jshn_parse(optarg);
case 'R':
if ((fd = open(optarg, O_RDONLY)) == -1) {
fprintf(stderr, "Error opening %s\n", optarg);
return 3;
}
if (fstat(fd, &sb) == -1) {
fprintf(stderr, "Error getting size of %s\n", optarg);
close(fd);
return 3;
}
if (!(fbuf = malloc(sb.st_size))) {
fprintf(stderr, "Error allocating memory for %s\n", optarg);
close(fd);
return 3;
}
if (read(fd, fbuf, sb.st_size) != sb.st_size) {
fprintf(stderr, "Error reading %s\n", optarg);
free(fbuf);
close(fd);
return 3;
}
ret = jshn_parse(fbuf);
free(fbuf);
close(fd);
return ret;
case 'w':
return jshn_format(no_newline, indent);
case 'n':
no_newline = true;
break;
case 'i':
indent = true;
break;
default:
return usage(argv[0]);
}
}
return usage(argv[0]);
}