main.c

   1 /*
   2  * Copyright (C) 2013-2014 Jo-Philipp Wich <jow@openwrt.org>
   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 <unistd.h>
  20 #include <errno.h>
  21
  22 #ifdef JSONC
  23         #include <json.h>
  24 #else
  25         #include <json-c/json.h>
  26 #endif
  27
  28 #include <libubox/list.h>
  29
  30 #include "lexer.h"
  31 #include "parser.h"
  32 #include "matcher.h"
  33
  34
  35 struct match_item {
  36         struct json_object *jsobj;
  37         struct list_head list;
  38 };
  39
  40 static struct json_object *
  41 parse_json(FILE *fd, const char *source, const char **error)
  42 {
  43         int len;
  44         char buf[256];
  45         struct json_object *obj = NULL;
  46         struct json_tokener *tok = json_tokener_new();
  47         enum json_tokener_error err = json_tokener_continue;
  48
  49         if (!tok)
  50                 return NULL;
  51
  52         if (source)
  53         {
  54                 obj = json_tokener_parse_ex(tok, source, strlen(source));
  55                 err = json_tokener_get_error(tok);
  56         }
  57         else
  58         {
  59                 while ((len = fread(buf, 1, sizeof(buf), fd)) > 0)
  60                 {
  61                         obj = json_tokener_parse_ex(tok, buf, len);
  62                         err = json_tokener_get_error(tok);
  63
  64                         if (!err || err != json_tokener_continue)
  65                                 break;
  66                 }
  67         }
  68
  69         json_tokener_free(tok);
  70
  71         if (err)
  72         {
  73                 if (err == json_tokener_continue)
  74                         err = json_tokener_error_parse_eof;
  75
  76                 *error = json_tokener_error_desc(err);
  77                 return NULL;
  78         }
  79
  80         return obj;
  81 }
  82
  83 static void
  84 print_string(const char *s)
  85 {
  86         const char *p;
  87
  88         printf("'");
  89
  90         for (p = s; *p; p++)
  91         {
  92                 if (*p == '\'')
  93                         printf("'\"'\"'");
  94                 else
  95                         printf("%c", *p);
  96         }
  97
  98         printf("'");
  99 }
 100
 101 static void
 102 export_value(struct list_head *matches, const char *prefix)
 103 {
 104         int n, len;
 105         bool first = true;
 106         struct match_item *item;
 107
 108         if (list_empty(matches))
 109                 return;
 110
 111         if (prefix)
 112         {
 113                 printf("export %s=", prefix);
 114
 115                 list_for_each_entry(item, matches, list)
 116                 {
 117                         switch (json_object_get_type(item->jsobj))
 118                         {
 119                         case json_type_object:
 120                                 ; /* a label can only be part of a statement */
 121                                 json_object_object_foreach(item->jsobj, key, val)
 122                                 {
 123                                         if (!val)
 124                                                 continue;
 125
 126                                         if (!first)
 127                                                 printf("\\ ");
 128
 129                                         print_string(key);
 130                                         first = false;
 131                                 }
 132                                 break;
 133
 134                         case json_type_array:
 135                                 for (n = 0, len = json_object_array_length(item->jsobj);
 136                                      n < len; n++)
 137                                 {
 138                                         if (!first)
 139                                                 printf("\\ ");
 140
 141                                         printf("%d", n);
 142                                         first = false;
 143                                 }
 144                                 break;
 145
 146                         case json_type_boolean:
 147                                 if (!first)
 148                                         printf("\\ ");
 149                                 printf("%d", json_object_get_boolean(item->jsobj));
 150                                 break;
 151
 152                         case json_type_int:
 153                                 if (!first)
 154                                         printf("\\ ");
 155                                 printf("%d", json_object_get_int(item->jsobj));
 156                                 break;
 157
 158                         case json_type_double:
 159                                 if (!first)
 160                                         printf("\\ ");
 161                                 printf("%f", json_object_get_double(item->jsobj));
 162                                 break;
 163
 164                         case json_type_string:
 165                                 if (!first)
 166                                         printf("\\ ");
 167                                 print_string(json_object_get_string(item->jsobj));
 168                                 break;
 169
 170                         case json_type_null:
 171                                 break;
 172                         }
 173
 174                         first = false;
 175                 }
 176
 177                 printf("; ");
 178         }
 179         else
 180         {
 181                 list_for_each_entry(item, matches, list)
 182                 {
 183                         switch (json_object_get_type(item->jsobj))
 184                         {
 185                         case json_type_object:
 186                         case json_type_array:
 187                         case json_type_boolean:
 188                         case json_type_int:
 189                         case json_type_double:
 190                                 printf("%s\n", json_object_to_json_string(item->jsobj));
 191                                 break;
 192
 193                         case json_type_string:
 194                                 printf("%s\n", json_object_get_string(item->jsobj));
 195                                 break;
 196
 197                         case json_type_null:
 198                                 break;
 199                         }
 200                 }
 201         }
 202 }
 203
 204 static void
 205 export_type(struct list_head *matches, const char *prefix)
 206 {
 207         bool first = true;
 208         struct match_item *item;
 209         const char *types[] = {
 210                 "null",
 211                 "boolean",
 212                 "double",
 213                 "int",
 214                 "object",
 215                 "array",
 216                 "string"
 217         };
 218
 219         if (list_empty(matches))
 220                 return;
 221
 222         if (prefix)
 223                 printf("export %s=", prefix);
 224
 225         list_for_each_entry(item, matches, list)
 226         {
 227                 if (!first)
 228                         printf("\\ ");
 229
 230                 printf("%s", types[json_object_get_type(item->jsobj)]);
 231                 first = false;
 232         }
 233
 234         if (prefix)
 235                 printf("; ");
 236         else
 237                 printf("\n");
 238 }
 239
 240 static void
 241 match_cb(struct json_object *res, void *priv)
 242 {
 243         struct list_head *h = priv;
 244         struct match_item *i = calloc(1, sizeof(*i));
 245
 246         if (i)
 247         {
 248                 i->jsobj = res;
 249                 list_add_tail(&i->list, h);
 250         }
 251 }
 252
 253 static void
 254 print_error(struct jp_state *state, char *expr)
 255 {
 256         int i;
 257         bool first = true;
 258
 259         fprintf(stderr, "Syntax error: ");
 260
 261         switch (state->error_code)
 262         {
 263         case -4:
 264                 fprintf(stderr, "Unexpected character\n");
 265                 break;
 266
 267         case -3:
 268                 fprintf(stderr, "String or label literal too long\n");
 269                 break;
 270
 271         case -2:
 272                 fprintf(stderr, "Invalid escape sequence\n");
 273                 break;
 274
 275         case -1:
 276                 fprintf(stderr, "Unterminated string\n");
 277                 break;
 278
 279         default:
 280                 for (i = 0; i < sizeof(state->error_code) * 8; i++)
 281                 {
 282                         if (state->error_code & (1 << i))
 283                         {
 284                                 fprintf(stderr,
 285                                         first ? "Expecting %s" : " or %s", tokennames[i]);
 286
 287                                 first = false;
 288                         }
 289                 }
 290
 291                 fprintf(stderr, "\n");
 292                 break;
 293         }
 294
 295         fprintf(stderr, "In expression %s\n", expr);
 296         fprintf(stderr, "Near here ----");
 297
 298         for (i = 0; i < state->error_pos; i++)
 299                 fprintf(stderr, "-");
 300
 301         fprintf(stderr, "^\n");
 302 }
 303
 304 static bool
 305 filter_json(int opt, struct json_object *jsobj, char *expr)
 306 {
 307         struct jp_state *state;
 308         const char *prefix = NULL;
 309         struct list_head matches;
 310         struct match_item *item, *tmp;
 311         struct json_object *res = NULL;
 312
 313         state = jp_parse(expr);
 314
 315         if (!state)
 316         {
 317                 fprintf(stderr, "Out of memory\n");
 318                 goto out;
 319         }
 320         else if (state->error_code)
 321         {
 322                 print_error(state, expr);
 323                 goto out;
 324         }
 325
 326         INIT_LIST_HEAD(&matches);
 327
 328         res = jp_match(state->path, jsobj, match_cb, &matches);
 329         prefix = (state->path->type == T_LABEL) ? state->path->str : NULL;
 330
 331         switch (opt)
 332         {
 333         case 't':
 334                 export_type(&matches, prefix);
 335                 break;
 336
 337         default:
 338                 export_value(&matches, prefix);
 339                 break;
 340         }
 341
 342         list_for_each_entry_safe(item, tmp, &matches, list)
 343                 free(item);
 344
 345 out:
 346         if (state)
 347                 jp_free(state);
 348
 349         return !!res;
 350 }
 351
 352 int main(int argc, char **argv)
 353 {
 354         int opt, rv = 0;
 355         FILE *input = stdin;
 356         struct json_object *jsobj = NULL;
 357         const char *jserr = NULL, *source = NULL;
 358
 359         while ((opt = getopt(argc, argv, "i:s:e:t:q")) != -1)
 360         {
 361                 switch (opt)
 362                 {
 363                 case 'i':
 364                         input = fopen(optarg, "r");
 365
 366                         if (!input)
 367                         {
 368                                 fprintf(stderr, "Failed to open %s: %s\n",
 369                                                 optarg, strerror(errno));
 370
 371                                 rv = 125;
 372                                 goto out;
 373                         }
 374
 375                         break;
 376
 377                 case 's':
 378                         source = optarg;
 379                         break;
 380
 381                 case 't':
 382                 case 'e':
 383                         if (!jsobj)
 384                         {
 385                                 jsobj = parse_json(input, source, &jserr);
 386
 387                                 if (!jsobj)
 388                                 {
 389                                         fprintf(stderr, "Failed to parse json data: %s\n",
 390                                                 jserr);
 391
 392                                         rv = 126;
 393                                         goto out;
 394                                 }
 395                         }
 396
 397                         if (!filter_json(opt, jsobj, optarg))
 398                                 rv = 1;
 399
 400                         break;
 401
 402                 case 'q':
 403                         fclose(stderr);
 404                         break;
 405                 }
 406         }
 407
 408 out:
 409         if (jsobj)
 410                 json_object_put(jsobj);
 411
 412         if (input != stdin)
 413                 fclose(input);
 414
 415         return rv;
 416 }