main.c

   1 /*
   2  * Copyright (C) 2013-2014 Jo-Philipp Wich <jo@mein.io>
   3  *
   4  * Permission to use, copy, modify, and/or distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15  */
  16
  17 #include <stdio.h>
  18 #include <stdbool.h>
  19 #include <stdint.h>
  20 #include <unistd.h>
  21 #include <errno.h>
  22
  23 #ifdef JSONC
  24         #include <json.h>
  25 #else
  26         #include <json-c/json.h>
  27 #endif
  28
  29 #include <libubox/list.h>
  30
  31 #include "lexer.h"
  32 #include "parser.h"
  33 #include "matcher.h"
  34
  35
  36 struct match_item {
  37         struct json_object *jsobj;
  38         struct list_head list;
  39 };
  40
  41 static void
  42 print_usage(char *app)
  43 {
  44         printf(
  45         "== Usage ==\n\n"
  46         "  # %s [-a] [-i <file> | -s \"json...\"] {-t <pattern> | -e <pattern>}\n"
  47         "  -q           Quiet, no errors are printed\n"
  48         "  -h, --help   Print this help\n"
  49         "  -a           Implicitely treat input as array, useful for JSON logs\n"
  50         "  -i path      Specify a JSON file to parse\n"
  51         "  -s \"json\"  Specify a JSON string to parse\n"
  52         "  -l limit     Specify max number of results to show\n"
  53         "  -F separator Specify a field separator when using export\n"
  54         "  -t <pattern> Print the type of values matched by pattern\n"
  55         "  -e <pattern> Print the values matched by pattern\n"
  56         "  -e VAR=<pat> Serialize matched value for shell \"eval\"\n\n"
  57         "== Patterns ==\n\n"
  58         "  Patterns are JsonPath: http://goessner.net/articles/JsonPath/\n"
  59         "  This tool implements $, @, [], * and the union operator ','\n"
  60         "  plus the usual expressions and literals.\n"
  61         "  It does not support the recursive child search operator '..' or\n"
  62         "  the '?()' and '()' filter expressions as those would require a\n"
  63         "  complete JavaScript engine to support them.\n\n"
  64         "== Examples ==\n\n"
  65         "  Display the first IPv4 address on lan:\n"
  66         "  # ifstatus lan | %s -e '@[\"ipv4-address\"][0].address'\n\n"
  67         "  Extract the release string from the board information:\n"
  68         "  # ubus call system board | %s -e '@.release.description'\n\n"
  69         "  Find all interfaces which are up:\n"
  70         "  # ubus call network.interface dump | \\\n"
  71         "       %s -e '@.interface[@.up=true].interface'\n\n"
  72         "  Export br-lan traffic counters for shell eval:\n"
  73         "  # devstatus br-lan | %s -e 'RX=@.statistics.rx_bytes' \\\n"
  74         "       -e 'TX=@.statistics.tx_bytes'\n",
  75                 app, app, app, app, app);
  76 }
  77
  78 static struct json_object *
  79 parse_json_chunk(struct json_tokener *tok, struct json_object *array,
  80                  const char *buf, size_t len, enum json_tokener_error *err)
  81 {
  82         struct json_object *obj = NULL;
  83
  84         while (len)
  85         {
  86                 obj = json_tokener_parse_ex(tok, buf, len);
  87                 *err = json_tokener_get_error(tok);
  88
  89                 if (*err == json_tokener_success)
  90                 {
  91                         if (array)
  92                         {
  93                                 json_object_array_add(array, obj);
  94                         }
  95                         else
  96                         {
  97                                 break;
  98                         }
  99                 }
 100                 else if (*err != json_tokener_continue)
 101                 {
 102                         break;
 103                 }
 104
 105                 buf += tok->char_offset;
 106                 len -= tok->char_offset;
 107         }
 108
 109         return obj;
 110 }
 111
 112 static struct json_object *
 113 parse_json(FILE *fd, const char *source, const char **error, bool array_mode)
 114 {
 115         size_t len;
 116         char buf[256];
 117         struct json_object *obj = NULL, *array = NULL;
 118         struct json_tokener *tok = json_tokener_new();
 119         enum json_tokener_error err = json_tokener_continue;
 120
 121         if (!tok)
 122         {
 123                 *error = "Out of memory";
 124                 return NULL;
 125         }
 126
 127         if (array_mode)
 128         {
 129                 array = json_object_new_array();
 130
 131                 if (!array)
 132                 {
 133                         json_tokener_free(tok);
 134                         *error = "Out of memory";
 135                         return NULL;
 136                 }
 137         }
 138
 139         if (source)
 140         {
 141                 obj = parse_json_chunk(tok, array, source, strlen(source), &err);
 142         }
 143         else
 144         {
 145                 while ((len = fread(buf, 1, sizeof(buf), fd)) > 0)
 146                 {
 147                         obj = parse_json_chunk(tok, array, buf, len, &err);
 148
 149                         if (err == json_tokener_success && !array)
 150                                 break;
 151
 152                         if (err != json_tokener_continue)
 153                                 break;
 154                 }
 155         }
 156
 157         json_tokener_free(tok);
 158
 159         if (err)
 160         {
 161                 if (err == json_tokener_continue)
 162                         err = json_tokener_error_parse_eof;
 163
 164                 *error = json_tokener_error_desc(err);
 165                 return NULL;
 166         }
 167
 168         return array ? array : obj;
 169 }
 170
 171 static void
 172 print_string(const char *s)
 173 {
 174         const char *p;
 175
 176         printf("'");
 177
 178         for (p = s; *p; p++)
 179         {
 180                 if (*p == '\'')
 181                         printf("'\"'\"'");
 182                 else
 183                         printf("%c", *p);
 184         }
 185
 186         printf("'");
 187 }
 188
 189 static void
 190 print_separator(const char *sep, int *sc, int sl)
 191 {
 192         if (*sc > 0)
 193         {
 194                 switch (sep[(*sc - 1) % sl])
 195                 {
 196                 case '"':
 197                         printf("'\"'");
 198                         break;
 199
 200                 case '\'':
 201                         printf("\"'\"");
 202                         break;
 203
 204                 case ' ':
 205                         printf("\\ ");
 206                         break;
 207
 208                 default:
 209                         printf("%c", sep[(*sc - 1) % sl]);
 210                 }
 211         }
 212
 213         (*sc)++;
 214 }
 215
 216 static void
 217 export_value(struct list_head *matches, const char *prefix, const char *sep,
 218              int limit)
 219 {
 220         int n, len;
 221         int sc = 0, sl = strlen(sep);
 222         struct match_item *item;
 223
 224         if (list_empty(matches))
 225                 return;
 226
 227         if (prefix)
 228         {
 229                 printf("export %s=", prefix);
 230
 231                 list_for_each_entry(item, matches, list)
 232                 {
 233                         if (limit-- <= 0)
 234                                 break;
 235
 236                         switch (json_object_get_type(item->jsobj))
 237                         {
 238                         case json_type_object:
 239                                 ; /* a label can only be part of a statement */
 240                                 json_object_object_foreach(item->jsobj, key, val)
 241                                 {
 242                                         if (!val)
 243                                                 continue;
 244
 245                                         print_separator(sep, &sc, sl);
 246                                         print_string(key);
 247                                 }
 248                                 break;
 249
 250                         case json_type_array:
 251                                 for (n = 0, len = json_object_array_length(item->jsobj);
 252                                      n < len; n++)
 253                                 {
 254                                         print_separator(sep, &sc, sl);
 255                                         printf("%d", n);
 256                                 }
 257                                 break;
 258
 259                         case json_type_boolean:
 260                                 print_separator(sep, &sc, sl);
 261                                 printf("%d", json_object_get_boolean(item->jsobj));
 262                                 break;
 263
 264                         case json_type_int:
 265                                 print_separator(sep, &sc, sl);
 266                                 printf("%" PRId64, json_object_get_int64(item->jsobj));
 267                                 break;
 268
 269                         case json_type_double:
 270                                 print_separator(sep, &sc, sl);
 271                                 printf("%f", json_object_get_double(item->jsobj));
 272                                 break;
 273
 274                         case json_type_string:
 275                                 print_separator(sep, &sc, sl);
 276                                 print_string(json_object_get_string(item->jsobj));
 277                                 break;
 278
 279                         case json_type_null:
 280                                 break;
 281                         }
 282                 }
 283
 284                 printf("; ");
 285         }
 286         else
 287         {
 288                 list_for_each_entry(item, matches, list)
 289                 {
 290                         if (limit-- <= 0)
 291                                 break;
 292
 293                         switch (json_object_get_type(item->jsobj))
 294                         {
 295                         case json_type_object:
 296                         case json_type_array:
 297                         case json_type_boolean:
 298                         case json_type_int:
 299                         case json_type_double:
 300                                 printf("%s\n", json_object_to_json_string(item->jsobj));
 301                                 break;
 302
 303                         case json_type_string:
 304                                 printf("%s\n", json_object_get_string(item->jsobj));
 305                                 break;
 306
 307                         case json_type_null:
 308                                 break;
 309                         }
 310                 }
 311         }
 312 }
 313
 314 static void
 315 export_type(struct list_head *matches, const char *prefix, int limit)
 316 {
 317         bool first = true;
 318         struct match_item *item;
 319         const char *types[] = {
 320                 "null",
 321                 "boolean",
 322                 "double",
 323                 "int",
 324                 "object",
 325                 "array",
 326                 "string"
 327         };
 328
 329         if (list_empty(matches))
 330                 return;
 331
 332         if (prefix)
 333                 printf("export %s=", prefix);
 334
 335         list_for_each_entry(item, matches, list)
 336         {
 337                 if (!first)
 338                         printf("\\ ");
 339
 340                 if (limit-- <= 0)
 341                         break;
 342
 343                 printf("%s", types[json_object_get_type(item->jsobj)]);
 344                 first = false;
 345         }
 346
 347         if (prefix)
 348                 printf("; ");
 349         else
 350                 printf("\n");
 351 }
 352
 353 static void
 354 match_cb(struct json_object *res, void *priv)
 355 {
 356         struct list_head *h = priv;
 357         struct match_item *i = calloc(1, sizeof(*i));
 358
 359         if (i)
 360         {
 361                 i->jsobj = res;
 362                 list_add_tail(&i->list, h);
 363         }
 364 }
 365
 366 static void
 367 print_error(struct jp_state *state, char *expr)
 368 {
 369         int i;
 370         bool first = true;
 371
 372         fprintf(stderr, "Syntax error: ");
 373
 374         switch (state->error_code)
 375         {
 376         case -4:
 377                 fprintf(stderr, "Unexpected character\n");
 378                 break;
 379
 380         case -3:
 381                 fprintf(stderr, "String or label literal too long\n");
 382                 break;
 383
 384         case -2:
 385                 fprintf(stderr, "Invalid escape sequence\n");
 386                 break;
 387
 388         case -1:
 389                 fprintf(stderr, "Unterminated string\n");
 390                 break;
 391
 392         default:
 393                 for (i = 0; i < sizeof(state->error_code) * 8; i++)
 394                 {
 395                         if (state->error_code & (1 << i))
 396                         {
 397                                 fprintf(stderr,
 398                                         first ? "Expecting %s" : " or %s", tokennames[i]);
 399
 400                                 first = false;
 401                         }
 402                 }
 403
 404                 fprintf(stderr, "\n");
 405                 break;
 406         }
 407
 408         fprintf(stderr, "In expression %s\n", expr);
 409         fprintf(stderr, "Near here ----");
 410
 411         for (i = 0; i < state->error_pos; i++)
 412                 fprintf(stderr, "-");
 413
 414         fprintf(stderr, "^\n");
 415 }
 416
 417 static bool
 418 filter_json(int opt, struct json_object *jsobj, char *expr, const char *sep,
 419             int limit)
 420 {
 421         struct jp_state *state;
 422         const char *prefix = NULL;
 423         struct list_head matches;
 424         struct match_item *item, *tmp;
 425         struct json_object *res = NULL;
 426
 427         state = jp_parse(expr);
 428
 429         if (!state)
 430         {
 431                 fprintf(stderr, "Out of memory\n");
 432                 goto out;
 433         }
 434         else if (state->error_code)
 435         {
 436                 print_error(state, expr);
 437                 goto out;
 438         }
 439
 440         INIT_LIST_HEAD(&matches);
 441
 442         res = jp_match(state->path, jsobj, match_cb, &matches);
 443         prefix = (state->path->type == T_LABEL) ? state->path->str : NULL;
 444
 445         switch (opt)
 446         {
 447         case 't':
 448                 export_type(&matches, prefix, limit);
 449                 break;
 450
 451         default:
 452                 export_value(&matches, prefix, sep, limit);
 453                 break;
 454         }
 455
 456         list_for_each_entry_safe(item, tmp, &matches, list)
 457                 free(item);
 458
 459 out:
 460         if (state)
 461                 jp_free(state);
 462
 463         return !!res;
 464 }
 465
 466 int main(int argc, char **argv)
 467 {
 468         bool array_mode = false;
 469         int opt, rv = 0, limit = 0x7FFFFFFF;
 470         FILE *input = stdin;
 471         struct json_object *jsobj = NULL;
 472         const char *jserr = NULL, *source = NULL, *separator = " ";
 473
 474         if (argc == 1)
 475         {
 476                 print_usage(argv[0]);
 477                 goto out;
 478         }
 479
 480         while ((opt = getopt(argc, argv, "ahi:s:e:t:F:l:q")) != -1)
 481         {
 482                 switch (opt)
 483                 {
 484                 case 'a':
 485                         array_mode = true;
 486                         break;
 487
 488                 case 'h':
 489                         print_usage(argv[0]);
 490                         goto out;
 491
 492                 case 'i':
 493                         input = fopen(optarg, "r");
 494
 495                         if (!input)
 496                         {
 497                                 fprintf(stderr, "Failed to open %s: %s\n",
 498                                                 optarg, strerror(errno));
 499
 500                                 rv = 125;
 501                                 goto out;
 502                         }
 503
 504                         break;
 505
 506                 case 's':
 507                         source = optarg;
 508                         break;
 509
 510                 case 'F':
 511                         if (optarg && *optarg)
 512                                 separator = optarg;
 513                         break;
 514
 515                 case 'l':
 516                         limit = atoi(optarg);
 517                         break;
 518
 519                 case 't':
 520                 case 'e':
 521                         if (!jsobj)
 522                         {
 523                                 jsobj = parse_json(input, source, &jserr, array_mode);
 524
 525                                 if (!jsobj)
 526                                 {
 527                                         fprintf(stderr, "Failed to parse json data: %s\n",
 528                                                 jserr);
 529
 530                                         rv = 126;
 531                                         goto out;
 532                                 }
 533                         }
 534
 535                         if (!filter_json(opt, jsobj, optarg, separator, limit))
 536                                 rv = 1;
 537
 538                         break;
 539
 540                 case 'q':
 541                         fclose(stderr);
 542                         break;
 543                 }
 544         }
 545
 546 out:
 547         if (jsobj)
 548                 json_object_put(jsobj);
 549
 550         if (input && input != stdin)
 551                 fclose(input);
 552
 553         return rv;
 554 }