jshn: drop json_select warnings when called from json_get_values()
[project/libubox.git] / json_script.c
1 /*
2 * Copyright (C) 2013 Felix Fietkau <nbd@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 #include <sys/stat.h>
17 #include <regex.h>
18
19 #include "avl-cmp.h"
20 #include "json_script.h"
21
22 struct json_call {
23 struct json_script_ctx *ctx;
24 struct blob_attr *vars;
25 unsigned int seq;
26 };
27
28 struct json_handler {
29 const char *name;
30 int (*cb)(struct json_call *call, struct blob_attr *cur);
31 };
32
33 static int json_process_expr(struct json_call *call, struct blob_attr *cur);
34 static int json_process_cmd(struct json_call *call, struct blob_attr *cur);
35
36 struct json_script_file *
37 json_script_file_from_blobmsg(const char *name, void *data, int len)
38 {
39 struct json_script_file *f;
40 char *new_name;
41 int name_len = 0;
42
43 if (name)
44 name_len = strlen(name) + 1;
45
46 f = calloc_a(sizeof(*f) + len, &new_name, name_len);
47 memcpy(f->data, data, len);
48 if (name)
49 f->avl.key = strcpy(new_name, name);
50
51 return f;
52 }
53
54 static struct json_script_file *
55 json_script_get_file(struct json_script_ctx *ctx, const char *filename)
56 {
57 struct json_script_file *f;
58
59 f = avl_find_element(&ctx->files, filename, f, avl);
60 if (f)
61 return f;
62
63 f = ctx->handle_file(ctx, filename);
64 if (!f)
65 return NULL;
66
67 avl_insert(&ctx->files, &f->avl);
68 return f;
69 }
70
71 static void __json_script_run(struct json_call *call, struct json_script_file *file,
72 struct blob_attr *context)
73 {
74 struct json_script_ctx *ctx = call->ctx;
75
76 if (file->seq == call->seq) {
77 if (context)
78 ctx->handle_error(ctx, "Recursive include", context);
79
80 return;
81 }
82
83 file->seq = call->seq;
84 while (file) {
85 json_process_cmd(call, file->data);
86 file = file->next;
87 }
88 }
89
90 const char *json_script_find_var(struct json_script_ctx *ctx, struct blob_attr *vars,
91 const char *name)
92 {
93 struct blob_attr *cur;
94 int rem;
95
96 blobmsg_for_each_attr(cur, vars, rem) {
97 if (blobmsg_type(cur) != BLOBMSG_TYPE_STRING)
98 continue;
99
100 if (strcmp(blobmsg_name(cur), name) != 0)
101 continue;
102
103 return blobmsg_data(cur);
104 }
105
106 return ctx->handle_var(ctx, name, vars);
107 }
108
109 static const char *
110 msg_find_var(struct json_call *call, const char *name)
111 {
112 return json_script_find_var(call->ctx, call->vars, name);
113 }
114
115 static void
116 json_get_tuple(struct blob_attr *cur, struct blob_attr **tb, int t1, int t2)
117 {
118 static struct blobmsg_policy expr_tuple[3] = {
119 { .type = BLOBMSG_TYPE_STRING },
120 {},
121 {},
122 };
123
124 expr_tuple[1].type = t1;
125 expr_tuple[2].type = t2;
126 blobmsg_parse_array(expr_tuple, 3, tb, blobmsg_data(cur), blobmsg_data_len(cur));
127 }
128
129 static int handle_if(struct json_call *call, struct blob_attr *expr)
130 {
131 struct blob_attr *tb[4];
132 int ret;
133
134 static const struct blobmsg_policy if_tuple[4] = {
135 { .type = BLOBMSG_TYPE_STRING },
136 { .type = BLOBMSG_TYPE_ARRAY },
137 { .type = BLOBMSG_TYPE_ARRAY },
138 { .type = BLOBMSG_TYPE_ARRAY },
139 };
140
141 blobmsg_parse_array(if_tuple, 4, tb, blobmsg_data(expr), blobmsg_data_len(expr));
142
143 if (!tb[1] || !tb[2])
144 return 0;
145
146 ret = json_process_expr(call, tb[1]);
147 if (ret < 0)
148 return 0;
149
150 if (ret)
151 return json_process_cmd(call, tb[2]);
152
153 if (!tb[3])
154 return 0;
155
156 return json_process_cmd(call, tb[3]);
157 }
158
159 static int handle_case(struct json_call *call, struct blob_attr *expr)
160 {
161 struct blob_attr *tb[3], *cur;
162 const char *var;
163 int rem;
164
165 json_get_tuple(expr, tb, BLOBMSG_TYPE_STRING, BLOBMSG_TYPE_TABLE);
166 if (!tb[1] || !tb[2])
167 return 0;
168
169 var = msg_find_var(call, blobmsg_data(tb[1]));
170 if (!var)
171 return 0;
172
173 blobmsg_for_each_attr(cur, tb[2], rem) {
174 if (!strcmp(var, blobmsg_name(cur)))
175 return json_process_cmd(call, cur);
176 }
177
178 return 0;
179 }
180
181 static int handle_return(struct json_call *call, struct blob_attr *expr)
182 {
183 return -2;
184 }
185
186 static int handle_include(struct json_call *call, struct blob_attr *expr)
187 {
188 struct blob_attr *tb[3];
189 struct json_script_file *f;
190
191 json_get_tuple(expr, tb, BLOBMSG_TYPE_STRING, 0);
192 if (!tb[1])
193 return 0;
194
195 f = json_script_get_file(call->ctx, blobmsg_data(tb[1]));
196 if (!f)
197 return 0;
198
199 __json_script_run(call, f, expr);
200 return 0;
201 }
202
203 static const struct json_handler cmd[] = {
204 { "if", handle_if },
205 { "case", handle_case },
206 { "return", handle_return },
207 { "include", handle_include },
208 };
209
210 static int eq_regex_cmp(const char *str, const char *pattern, bool regex)
211 {
212 regex_t reg;
213 int ret;
214
215 if (!regex)
216 return !strcmp(str, pattern);
217
218 if (regcomp(&reg, pattern, REG_EXTENDED | REG_NOSUB))
219 return 0;
220
221 ret = !regexec(&reg, str, 0, NULL, 0);
222 regfree(&reg);
223
224 return ret;
225 }
226
227 static int expr_eq_regex(struct json_call *call, struct blob_attr *expr, bool regex)
228 {
229 struct json_script_ctx *ctx = call->ctx;
230 struct blob_attr *tb[3], *cur;
231 const char *var;
232 int rem;
233
234 json_get_tuple(expr, tb, BLOBMSG_TYPE_STRING, 0);
235 if (!tb[1] || !tb[2])
236 return -1;
237
238 var = msg_find_var(call, blobmsg_data(tb[1]));
239 if (!var)
240 return 0;
241
242 switch(blobmsg_type(tb[2])) {
243 case BLOBMSG_TYPE_STRING:
244 return eq_regex_cmp(var, blobmsg_data(tb[2]), regex);
245 case BLOBMSG_TYPE_ARRAY:
246 blobmsg_for_each_attr(cur, tb[2], rem) {
247 if (blobmsg_type(cur) != BLOBMSG_TYPE_STRING) {
248 ctx->handle_error(ctx, "Unexpected element type", cur);
249 return -1;
250 }
251
252 if (eq_regex_cmp(var, blobmsg_data(cur), regex))
253 return 1;
254 }
255 return 0;
256 default:
257 ctx->handle_error(ctx, "Unexpected element type", tb[2]);
258 return -1;
259 }
260 }
261
262 static int handle_expr_eq(struct json_call *call, struct blob_attr *expr)
263 {
264 return expr_eq_regex(call, expr, false);
265 }
266
267 static int handle_expr_regex(struct json_call *call, struct blob_attr *expr)
268 {
269 return expr_eq_regex(call, expr, true);
270 }
271
272 static int handle_expr_has(struct json_call *call, struct blob_attr *expr)
273 {
274 struct json_script_ctx *ctx = call->ctx;
275 struct blob_attr *tb[3], *cur;
276 int rem;
277
278 json_get_tuple(expr, tb, 0, 0);
279 if (!tb[1])
280 return -1;
281
282 switch(blobmsg_type(tb[1])) {
283 case BLOBMSG_TYPE_STRING:
284 return !!msg_find_var(call, blobmsg_data(tb[1]));
285 case BLOBMSG_TYPE_ARRAY:
286 blobmsg_for_each_attr(cur, tb[1], rem) {
287 if (blobmsg_type(cur) != BLOBMSG_TYPE_STRING) {
288 ctx->handle_error(ctx, "Unexpected element type", cur);
289 return -1;
290 }
291
292 if (msg_find_var(call, blobmsg_data(cur)))
293 return 1;
294 }
295 return 0;
296 default:
297 ctx->handle_error(ctx, "Unexpected element type", tb[1]);
298 return -1;
299 }
300 }
301
302 static int expr_and_or(struct json_call *call, struct blob_attr *expr, bool and)
303 {
304 struct blob_attr *cur;
305 int ret, rem;
306 int i = 0;
307
308 blobmsg_for_each_attr(cur, expr, rem) {
309 if (i++ < 1)
310 continue;
311
312 ret = json_process_expr(call, cur);
313 if (ret < 0)
314 return ret;
315
316 if (ret != and)
317 return ret;
318 }
319
320 return and;
321 }
322
323 static int handle_expr_and(struct json_call *call, struct blob_attr *expr)
324 {
325 return expr_and_or(call, expr, 1);
326 }
327
328 static int handle_expr_or(struct json_call *call, struct blob_attr *expr)
329 {
330 return expr_and_or(call, expr, 0);
331 }
332
333 static int handle_expr_not(struct json_call *call, struct blob_attr *expr)
334 {
335 struct blob_attr *tb[3];
336
337 json_get_tuple(expr, tb, BLOBMSG_TYPE_ARRAY, 0);
338 if (!tb[1])
339 return -1;
340
341 return json_process_expr(call, tb[1]);
342 }
343
344 static const struct json_handler expr[] = {
345 { "eq", handle_expr_eq },
346 { "regex", handle_expr_regex },
347 { "has", handle_expr_has },
348 { "and", handle_expr_and },
349 { "or", handle_expr_or },
350 { "not", handle_expr_not },
351 };
352
353 static int
354 __json_process_type(struct json_call *call, struct blob_attr *cur,
355 const struct json_handler *h, int n, bool *found)
356 {
357 const char *name = blobmsg_data(blobmsg_data(cur));
358 int i;
359
360 for (i = 0; i < n; i++) {
361 if (strcmp(name, h[i].name) != 0)
362 continue;
363
364 *found = true;
365 return h[i].cb(call, cur);
366 }
367
368 *found = false;
369 return -1;
370 }
371
372 static int json_process_expr(struct json_call *call, struct blob_attr *cur)
373 {
374 struct json_script_ctx *ctx = call->ctx;
375 bool found;
376 int ret;
377
378 if (blobmsg_type(cur) != BLOBMSG_TYPE_ARRAY ||
379 blobmsg_type(blobmsg_data(cur)) != BLOBMSG_TYPE_STRING) {
380 ctx->handle_error(ctx, "Unexpected element type", cur);
381 return -1;
382 }
383
384 ret = __json_process_type(call, cur, expr, ARRAY_SIZE(expr), &found);
385 if (!found)
386 ctx->handle_error(ctx, "Unknown expression type", cur);
387
388 return ret;
389 }
390
391 static int cmd_add_string(struct json_call *call, const char *pattern)
392 {
393 struct json_script_ctx *ctx = call->ctx;
394 char *dest, *next, *str;
395 int len = 0;
396 bool var = false;
397 char c = '%';
398
399 dest = blobmsg_alloc_string_buffer(&ctx->buf, NULL, 1);
400 next = alloca(strlen(pattern) + 1);
401 strcpy(next, pattern);
402
403 for (str = next; str; str = next) {
404 const char *cur;
405 char *end;
406 int cur_len = 0;
407 bool cur_var = var;
408
409 end = strchr(str, '%');
410 if (end) {
411 *end = 0;
412 next = end + 1;
413 var = !var;
414 } else {
415 end = str + strlen(str);
416 next = NULL;
417 }
418
419 if (cur_var) {
420 if (next > str) {
421 cur = msg_find_var(call, str);
422 if (!cur)
423 continue;
424
425 cur_len = strlen(cur);
426 } else {
427 cur = &c;
428 cur_len = 1;
429 }
430 } else {
431 if (str == end)
432 continue;
433
434 cur = str;
435 cur_len = end - str;
436 }
437
438 dest = blobmsg_realloc_string_buffer(&ctx->buf, cur_len + 1);
439 memcpy(dest + len, cur, cur_len);
440 len += cur_len;
441 }
442
443 if (var)
444 return -1;
445
446 dest[len] = 0;
447 blobmsg_add_string_buffer(&ctx->buf);
448 return 0;
449 }
450
451 static int cmd_process_strings(struct json_call *call, struct blob_attr *attr)
452 {
453 struct json_script_ctx *ctx = call->ctx;
454 struct blob_attr *cur;
455 int args = -1;
456 int rem, ret;
457 void *c;
458
459 blob_buf_init(&ctx->buf, 0);
460 c = blobmsg_open_array(&ctx->buf, NULL);
461 blobmsg_for_each_attr(cur, attr, rem) {
462 if (args++ < 0)
463 continue;
464
465 if (blobmsg_type(cur) != BLOBMSG_TYPE_STRING) {
466 ctx->handle_error(ctx, "Invalid argument in command", attr);
467 return -1;
468 }
469
470 ret = cmd_add_string(call, blobmsg_data(cur));
471 if (ret) {
472 ctx->handle_error(ctx, "Unterminated variable reference in string", attr);
473 return ret;
474 }
475 }
476
477 blobmsg_close_array(&ctx->buf, c);
478
479 return 0;
480 }
481
482 static int __json_process_cmd(struct json_call *call, struct blob_attr *cur)
483 {
484 struct json_script_ctx *ctx = call->ctx;
485 const char *name;
486 bool found;
487 int ret;
488
489 if (blobmsg_type(cur) != BLOBMSG_TYPE_ARRAY ||
490 blobmsg_type(blobmsg_data(cur)) != BLOBMSG_TYPE_STRING) {
491 ctx->handle_error(ctx, "Unexpected element type", cur);
492 return -1;
493 }
494
495 ret = __json_process_type(call, cur, cmd, ARRAY_SIZE(cmd), &found);
496 if (found)
497 return ret;
498
499 name = blobmsg_data(blobmsg_data(cur));
500 ret = cmd_process_strings(call, cur);
501 if (ret)
502 return ret;
503
504 ctx->handle_command(ctx, name, blob_data(ctx->buf.head), call->vars);
505
506 return 0;
507 }
508
509 static int json_process_cmd(struct json_call *call, struct blob_attr *block)
510 {
511 struct json_script_ctx *ctx = call->ctx;
512 struct blob_attr *cur;
513 int rem;
514 int ret;
515 int i = 0;
516
517 if (blobmsg_type(block) != BLOBMSG_TYPE_ARRAY) {
518 ctx->handle_error(ctx, "Unexpected element type", block);
519 return -1;
520 }
521
522 blobmsg_for_each_attr(cur, block, rem) {
523 switch(blobmsg_type(cur)) {
524 case BLOBMSG_TYPE_STRING:
525 if (!i)
526 return __json_process_cmd(call, block);
527 default:
528 ret = json_process_cmd(call, cur);
529 if (ret < -1)
530 return ret;
531 break;
532 }
533 i++;
534 }
535
536 return 0;
537 }
538
539 void json_script_run(struct json_script_ctx *ctx, const char *name,
540 struct blob_attr *vars)
541 {
542 struct json_script_file *file;
543 static unsigned int _seq = 0;
544 struct json_call call = {
545 .ctx = ctx,
546 .vars = vars,
547 .seq = ++_seq,
548 };
549
550 /* overflow */
551 if (!call.seq)
552 call.seq = ++_seq;
553
554 file = json_script_get_file(ctx, name);
555 if (!file)
556 return;
557
558 __json_script_run(&call, file, NULL);
559 }
560
561 static void __json_script_file_free(struct json_script_ctx *ctx, struct json_script_file *f)
562 {
563 struct json_script_file *next;
564
565 for (next = f->next; f; f = next, next = f->next)
566 free(f);
567 }
568
569 void
570 json_script_free(struct json_script_ctx *ctx)
571 {
572 struct json_script_file *f, *next;
573
574 avl_remove_all_elements(&ctx->files, f, avl, next)
575 __json_script_file_free(ctx, f);
576
577 blob_buf_free(&ctx->buf);
578 }
579
580 static void
581 __default_handle_error(struct json_script_ctx *ctx, const char *msg,
582 struct blob_attr *context)
583 {
584 }
585
586 static const char *
587 __default_handle_var(struct json_script_ctx *ctx, const char *name,
588 struct blob_attr *vars)
589 {
590 return NULL;
591 }
592
593 static int
594 __default_handle_expr(struct json_script_ctx *ctx, const char *name,
595 struct blob_attr *expr, struct blob_attr *vars)
596 {
597 return -1;
598 }
599
600 static struct json_script_file *
601 __default_handle_file(struct json_script_ctx *ctx, const char *name)
602 {
603 return NULL;
604 }
605
606 void json_script_init(struct json_script_ctx *ctx)
607 {
608 avl_init(&ctx->files, avl_strcmp, false, NULL);
609
610 if (!ctx->handle_error)
611 ctx->handle_error = __default_handle_error;
612
613 if (!ctx->handle_var)
614 ctx->handle_var = __default_handle_var;
615
616 if (!ctx->handle_expr)
617 ctx->handle_expr = __default_handle_expr;
618
619 if (!ctx->handle_file)
620 ctx->handle_file = __default_handle_file;
621 }