src/afb-hook.c

   1 /*
   2  * Copyright (C) 2016 "IoT.bzh"
   3  * Author José Bollo <jose.bollo@iot.bzh>
   4  *
   5  * Licensed under the Apache License, Version 2.0 (the "License");
   6  * you may not use this file except in compliance with the License.
   7  * You may obtain a copy of the License at
   8  *
   9  *   http://www.apache.org/licenses/LICENSE-2.0
  10  *
  11  * Unless required by applicable law or agreed to in writing, software
  12  * distributed under the License is distributed on an "AS IS" BASIS,
  13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14  * See the License for the specific language governing permissions and
  15  * limitations under the License.
  16  */
  17
  18 #define _GNU_SOURCE
  19
  20 #include <stdio.h>
  21 #include <stdarg.h>
  22 #include <string.h>
  23
  24 #include <json-c/json.h>
  25
  26 #include <afb/afb-req-itf.h>
  27 #include <afb/afb-event-itf.h>
  28
  29 #include "afb-context.h"
  30 #include "afb-hook.h"
  31 #include "session.h"
  32 #include "verbose.h"
  33
  34 /*
  35  * Definition of a hook
  36  */
  37 struct afb_hook {
  38         struct afb_hook *next; /* next hook */
  39         unsigned refcount; /* reference count */
  40         char *api; /* api hooked or NULL for any */
  41         char *verb; /* verb hooked or NULL for any */
  42         struct AFB_clientCtx *session; /* session hooked or NULL if any */
  43         unsigned flags; /* hook flags */
  44         struct afb_hook_req_itf *reqitf; /* interface of hook */
  45         void *closure; /* closure for callbacks */
  46 };
  47
  48 /*
  49  * Link hooks to a hooked request
  50  */
  51 struct hook_req_observer {
  52         struct afb_hook *hook; /* the hook */
  53         struct hook_req_observer *next; /* the next observer */
  54 };
  55
  56 /*
  57  * Structure recording a request to hook
  58  */
  59 struct afb_hook_req {
  60         struct hook_req_observer *observers; /* observers */
  61         struct afb_context *context; /* context of the request */
  62         struct afb_req req; /* the request hookd */
  63         unsigned refcount; /* reference count proxy for request */
  64         char name[1]; /* hook info for the request */
  65 };
  66
  67 /*
  68  * Structure for handling subcalls callbacks
  69  */
  70 struct hook_subcall {
  71         struct afb_hook_req *tr; /* hookd request */
  72         void (*callback)(void*, int, struct json_object*); /* client callback */
  73         void *cb_closure; /* cient closure */
  74 };
  75
  76 /* counter of hooking */
  77 static unsigned hook_count = 0;
  78
  79 /* list of hooks */
  80 static struct afb_hook *list_of_hooks = NULL;
  81
  82 /******************************************************************************
  83  * section: default callbacks for tracing requests
  84  *****************************************************************************/
  85
  86 static void _hook_(const struct afb_hook_req *tr, const char *format, ...)
  87 {
  88         int len;
  89         char *buffer;
  90         va_list ap;
  91
  92         va_start(ap, format);
  93         len = vasprintf(&buffer, format, ap);
  94         va_end(ap);
  95
  96         if (len < 0)
  97                 NOTICE("tracing %s allocation error", tr->name);
  98         else {
  99                 NOTICE("hook %s %s", tr->name, buffer);
 100                 free(buffer);
 101         }
 102 }
 103
 104 static void hook_req_begin_default_cb(void * closure, const struct afb_hook_req *tr)
 105 {
 106         _hook_(tr, "BEGIN");
 107 }
 108
 109 static void hook_req_end_default_cb(void * closure, const struct afb_hook_req *tr)
 110 {
 111         _hook_(tr, "END");
 112 }
 113
 114 static void hook_req_json_default_cb(void * closure, const struct afb_hook_req *tr, struct json_object *obj)
 115 {
 116         _hook_(tr, "json() -> %s", json_object_to_json_string(obj));
 117 }
 118
 119 static void hook_req_get_default_cb(void * closure, const struct afb_hook_req *tr, const char *name, struct afb_arg arg)
 120 {
 121         _hook_(tr, "get(%s) -> { name: %s, value: %s, path: %s }", name, arg.name, arg.value, arg.path);
 122 }
 123
 124 static void hook_req_success_default_cb(void * closure, const struct afb_hook_req *tr, struct json_object *obj, const char *info)
 125 {
 126         _hook_(tr, "success(%s, %s)", json_object_to_json_string(obj), info);
 127 }
 128
 129 static void hook_req_fail_default_cb(void * closure, const struct afb_hook_req *tr, const char *status, const char *info)
 130 {
 131         _hook_(tr, "fail(%s, %s)", status, info);
 132 }
 133
 134 static void hook_req_raw_default_cb(void * closure, const struct afb_hook_req *tr, const char *buffer, size_t size)
 135 {
 136         _hook_(tr, "raw() -> %.*s", (int)size, buffer);
 137 }
 138
 139 static void hook_req_send_default_cb(void * closure, const struct afb_hook_req *tr, const char *buffer, size_t size)
 140 {
 141         _hook_(tr, "send(%.*s)", (int)size, buffer);
 142 }
 143
 144 static void hook_req_context_get_default_cb(void * closure, const struct afb_hook_req *tr, void *value)
 145 {
 146         _hook_(tr, "context_get() -> %p", value);
 147 }
 148
 149 static void hook_req_context_set_default_cb(void * closure, const struct afb_hook_req *tr, void *value, void (*free_value)(void*))
 150 {
 151         _hook_(tr, "context_set(%p, %p)", value, free_value);
 152 }
 153
 154 static void hook_req_addref_default_cb(void * closure, const struct afb_hook_req *tr)
 155 {
 156         _hook_(tr, "addref()");
 157 }
 158
 159 static void hook_req_unref_default_cb(void * closure, const struct afb_hook_req *tr)
 160 {
 161         _hook_(tr, "unref()");
 162 }
 163
 164 static void hook_req_session_close_default_cb(void * closure, const struct afb_hook_req *tr)
 165 {
 166         _hook_(tr, "session_close()");
 167 }
 168
 169 static void hook_req_session_set_LOA_default_cb(void * closure, const struct afb_hook_req *tr, unsigned level, int result)
 170 {
 171         _hook_(tr, "session_set_LOA(%u) -> %d", level, result);
 172 }
 173
 174 static void hook_req_subscribe_default_cb(void * closure, const struct afb_hook_req *tr, struct afb_event event, int result)
 175 {
 176         _hook_(tr, "subscribe(%s:%p) -> %d", afb_event_name(event), event.closure, result);
 177 }
 178
 179 static void hook_req_unsubscribe_default_cb(void * closure, const struct afb_hook_req *tr, struct afb_event event, int result)
 180 {
 181         _hook_(tr, "unsubscribe(%s:%p) -> %d", afb_event_name(event), event.closure, result);
 182 }
 183
 184 static void hook_req_subcall_default_cb(void * closure, const struct afb_hook_req *tr, const char *api, const char *verb, struct json_object *args)
 185 {
 186         _hook_(tr, "subcall(%s/%s, %s) ...", api, verb, json_object_to_json_string(args));
 187 }
 188
 189 static void hook_req_subcall_result_default_cb(void * closure, const struct afb_hook_req *tr, int status, struct json_object *result)
 190 {
 191         _hook_(tr, "    ...subcall... -> %d: %s", status, json_object_to_json_string(result));
 192 }
 193
 194 static struct afb_hook_req_itf hook_req_default_itf = {
 195         .hook_req_begin = hook_req_begin_default_cb,
 196         .hook_req_end = hook_req_end_default_cb,
 197         .hook_req_json = hook_req_json_default_cb,
 198         .hook_req_get = hook_req_get_default_cb,
 199         .hook_req_success = hook_req_success_default_cb,
 200         .hook_req_fail = hook_req_fail_default_cb,
 201         .hook_req_raw = hook_req_raw_default_cb,
 202         .hook_req_send = hook_req_send_default_cb,
 203         .hook_req_context_get = hook_req_context_get_default_cb,
 204         .hook_req_context_set = hook_req_context_set_default_cb,
 205         .hook_req_addref = hook_req_addref_default_cb,
 206         .hook_req_unref = hook_req_unref_default_cb,
 207         .hook_req_session_close = hook_req_session_close_default_cb,
 208         .hook_req_session_set_LOA = hook_req_session_set_LOA_default_cb,
 209         .hook_req_subscribe = hook_req_subscribe_default_cb,
 210         .hook_req_unsubscribe = hook_req_unsubscribe_default_cb,
 211         .hook_req_subcall = hook_req_subcall_default_cb,
 212         .hook_req_subcall_result = hook_req_subcall_result_default_cb,
 213 };
 214
 215 /******************************************************************************
 216  * section: macro for tracing requests
 217  *****************************************************************************/
 218
 219 #define TRACE_REQX(what,tr) do{\
 220                 struct hook_req_observer *observer = tr->observers;\
 221                 while (observer != NULL) {\
 222                         struct afb_hook *hook = observer->hook;\
 223                         observer = observer->next;\
 224                         if (hook->reqitf && hook->reqitf->hook_req_##what)\
 225                                 hook->reqitf->hook_req_##what(hook->closure, tr);\
 226                 }\
 227         }while(0)
 228
 229 #define TRACE_REQ_(what,tr) do{\
 230                 struct hook_req_observer *observer = tr->observers;\
 231                 while (observer != NULL) {\
 232                         struct afb_hook *hook = observer->hook;\
 233                         observer = observer->next;\
 234                         if ((hook->flags & afb_hook_flag_req_##what) && hook->reqitf && hook->reqitf->hook_req_##what)\
 235                                 hook->reqitf->hook_req_##what(hook->closure, tr);\
 236                 }\
 237         }while(0)
 238
 239 #define TRACE_REQ(what,tr,...) do{\
 240                 struct hook_req_observer *observer = tr->observers;\
 241                 while (observer != NULL) {\
 242                         struct afb_hook *hook = observer->hook;\
 243                         observer = observer->next;\
 244                         if ((hook->flags & afb_hook_flag_req_##what) && hook->reqitf && hook->reqitf->hook_req_##what)\
 245                                 hook->reqitf->hook_req_##what(hook->closure, tr, __VA_ARGS__);\
 246                 }\
 247         }while(0)
 248
 249 /******************************************************************************
 250  * section: afb_hook_req handling
 251  *****************************************************************************/
 252
 253 static void hook_req_addref(struct afb_hook_req *tr)
 254 {
 255         tr->refcount++;
 256 }
 257
 258 static void hook_req_unref(struct afb_hook_req *tr)
 259 {
 260         struct hook_req_observer *o1, *o2;
 261         if (!--tr->refcount) {
 262                 TRACE_REQX(end, tr);
 263                 afb_req_unref(tr->req);
 264                 o1 = tr->observers;
 265                 while(o1) {
 266                         afb_hook_unref(o1->hook);
 267                         o2 = o1->next;
 268                         free(o1);
 269                         o1 = o2;
 270                 }
 271                 free(tr);
 272         }
 273 }
 274
 275 static struct afb_hook_req *hook_req_create(struct afb_req req, struct afb_context *context, const char *api, size_t lenapi, const char *verb, size_t lenverb)
 276 {
 277         unsigned id;
 278         struct afb_hook_req *tr;
 279
 280         tr = malloc(sizeof *tr + 8 + lenapi + lenverb);
 281         if (tr != NULL) {
 282                 /* get the call id */
 283                 id = ++hook_count;
 284                 if (id == 1000000)
 285                         id = hook_count = 1;
 286
 287                 /* init hook */
 288                 tr->observers = NULL;
 289                 tr->refcount = 1;
 290                 tr->context = context;
 291                 tr->req = req;
 292                 afb_req_addref(req);
 293                 snprintf(tr->name, 9 + lenapi + lenverb, "%06d:%.*s/%.*s", id, (int)lenapi, api, (int)lenverb, verb);
 294         }
 295         return tr;
 296 }
 297
 298 static void hook_req_add_observer(struct afb_hook_req *tr, struct afb_hook *hook)
 299 {
 300         struct hook_req_observer *observer;
 301
 302         observer = malloc(sizeof *observer);
 303         if (observer) {
 304                 observer->hook = afb_hook_addref(hook);
 305                 observer->next = tr->observers;
 306                 tr->observers = observer;
 307         }
 308 }
 309
 310 /******************************************************************************
 311  * section: hooks for tracing requests
 312  *****************************************************************************/
 313
 314 static struct json_object *req_hook_json(void *closure)
 315 {
 316         struct afb_hook_req *tr = closure;
 317         struct json_object *r;
 318
 319         r = afb_req_json(tr->req);
 320         TRACE_REQ(json, tr, r);
 321         return r;
 322 }
 323
 324 static struct afb_arg req_hook_get(void *closure, const char *name)
 325 {
 326         struct afb_hook_req *tr = closure;
 327         struct afb_arg a;
 328
 329         a = afb_req_get(tr->req, name);
 330         TRACE_REQ(get, tr, name, a);
 331         return a;
 332 }
 333
 334 static void req_hook_success(void *closure, struct json_object *obj, const char *info)
 335 {
 336         struct afb_hook_req *tr = closure;
 337
 338         TRACE_REQ(success, tr, obj, info);
 339         afb_req_success(tr->req, obj, info);
 340         hook_req_unref(tr);
 341 }
 342
 343 static void req_hook_fail(void *closure, const char *status, const char *info)
 344 {
 345         struct afb_hook_req *tr = closure;
 346
 347         TRACE_REQ(fail, tr, status, info);
 348         afb_req_fail(tr->req, status, info);
 349         hook_req_unref(tr);
 350 }
 351
 352 static const char *req_hook_raw(void *closure, size_t *size)
 353 {
 354         struct afb_hook_req *tr = closure;
 355         const char *r;
 356         size_t s;
 357
 358         r = afb_req_raw(tr->req, &s);
 359         TRACE_REQ(raw, tr, r, s);
 360         if (size)
 361                 *size = s;
 362         return r;
 363 }
 364
 365 static void req_hook_send(void *closure, const char *buffer, size_t size)
 366 {
 367         struct afb_hook_req *tr = closure;
 368
 369         TRACE_REQ(send, tr, buffer, size);
 370         afb_req_send(tr->req, buffer, size);
 371 }
 372
 373 static void *req_hook_context_get(void *closure)
 374 {
 375         struct afb_hook_req *tr = closure;
 376         void *r;
 377
 378         r = afb_req_context_get(tr->req);
 379         TRACE_REQ(context_get, tr, r);
 380
 381         return r;
 382 }
 383
 384 static void req_hook_context_set(void *closure, void *value, void (*free_value)(void*))
 385 {
 386         struct afb_hook_req *tr = closure;
 387
 388         TRACE_REQ(context_set, tr, value, free_value);
 389         afb_req_context_set(tr->req, value, free_value);
 390 }
 391
 392 static void req_hook_addref(void *closure)
 393 {
 394         struct afb_hook_req *tr = closure;
 395
 396         TRACE_REQ_(addref, tr);
 397         hook_req_addref(tr);
 398 }
 399
 400 static void req_hook_unref(void *closure)
 401 {
 402         struct afb_hook_req *tr = closure;
 403
 404         TRACE_REQ_(unref, tr);
 405         hook_req_unref(tr);
 406 }
 407
 408 static void req_hook_session_close(void *closure)
 409 {
 410         struct afb_hook_req *tr = closure;
 411
 412         TRACE_REQ_(session_close, tr);
 413         afb_req_session_close(tr->req);
 414 }
 415
 416 static int req_hook_session_set_LOA(void *closure, unsigned level)
 417 {
 418         struct afb_hook_req *tr = closure;
 419         int r;
 420
 421         r = afb_req_session_set_LOA(tr->req, level);
 422         TRACE_REQ(session_set_LOA, tr, level, r);
 423         return r;
 424 }
 425
 426 static int req_hook_subscribe(void *closure, struct afb_event event)
 427 {
 428         struct afb_hook_req *tr = closure;
 429         int r;
 430
 431         r = afb_req_subscribe(tr->req, event);
 432         TRACE_REQ(subscribe, tr, event, r);
 433         return r;
 434 }
 435
 436 static int req_hook_unsubscribe(void *closure, struct afb_event event)
 437 {
 438         struct afb_hook_req *tr = closure;
 439         int r;
 440
 441         r = afb_req_unsubscribe(tr->req, event);
 442         TRACE_REQ(unsubscribe, tr, event, r);
 443         return r;
 444 }
 445
 446 static void req_hook_subcall_result(void *closure, int status, struct json_object *result)
 447 {
 448         struct hook_subcall *sc = closure;
 449         struct hook_subcall s = *sc;
 450
 451         free(sc);
 452         TRACE_REQ(subcall_result, s.tr, status, result);
 453         hook_req_unref(s.tr);
 454         s.callback(s.cb_closure, status, result);
 455 }
 456
 457 static void req_hook_subcall(void *closure, const char *api, const char *verb, struct json_object *args, void (*callback)(void*, int, struct json_object*), void *cb_closure)
 458 {
 459         struct afb_hook_req *tr = closure;
 460         struct hook_subcall *sc;
 461
 462         TRACE_REQ(subcall, tr, api, verb, args);
 463         sc = malloc(sizeof *sc);
 464         if (sc) {
 465                 sc->tr = tr;
 466                 sc->callback = callback;
 467                 sc->cb_closure = cb_closure;
 468                 hook_req_addref(tr);
 469                 cb_closure = sc;
 470                 callback = req_hook_subcall_result;
 471         }
 472         afb_req_subcall(tr->req, api, verb, args, callback, cb_closure);
 473 }
 474
 475 static struct afb_req_itf req_hook_itf = {
 476         .json = req_hook_json,
 477         .get = req_hook_get,
 478         .success = req_hook_success,
 479         .fail = req_hook_fail,
 480         .raw = req_hook_raw,
 481         .send = req_hook_send,
 482         .context_get = req_hook_context_get,
 483         .context_set = req_hook_context_set,
 484         .addref = req_hook_addref,
 485         .unref = req_hook_unref,
 486         .session_close = req_hook_session_close,
 487         .session_set_LOA = req_hook_session_set_LOA,
 488         .subscribe = req_hook_subscribe,
 489         .unsubscribe = req_hook_unsubscribe,
 490         .subcall = req_hook_subcall
 491 };
 492
 493 /******************************************************************************
 494  * section:
 495  *****************************************************************************/
 496
 497 struct afb_req afb_hook_req_call(struct afb_req req, struct afb_context *context, const char *api, size_t lenapi, const char *verb, size_t lenverb)
 498 {
 499         int add;
 500         struct afb_hook_req *tr;
 501         struct afb_hook *hook;
 502
 503         hook = list_of_hooks;
 504         if (hook) {
 505                 tr = NULL;
 506                 do {
 507                         add = (hook->flags & afb_hook_flags_req_all) != 0
 508                            && (!hook->session || hook->session == context->session)
 509                            && (!hook->api || !(memcmp(hook->api, api, lenapi) || hook->api[lenapi]))
 510                            && (!hook->verb || !(memcmp(hook->verb, verb, lenverb) || hook->verb[lenverb]));
 511                         if (add) {
 512                                 if (!tr)
 513                                         tr = hook_req_create(req, context, api, lenapi, verb, lenverb);
 514                                 if (tr)
 515                                         hook_req_add_observer(tr, hook);
 516                         }
 517                         hook = hook->next;
 518                 } while(hook);
 519                 if (tr) {
 520                         req.closure = tr;
 521                         req.itf = &req_hook_itf;
 522                         TRACE_REQX(begin, tr);
 523                 }
 524         }
 525
 526         return req;
 527 }
 528
 529 struct afb_hook *afb_hook_req_create(const char *api, const char *verb, struct AFB_clientCtx *session, unsigned flags, struct afb_hook_req_itf *itf, void *closure)
 530 {
 531         struct afb_hook *hook;
 532
 533         hook = malloc(sizeof *hook);
 534         if (hook == NULL)
 535                 return NULL;
 536
 537         hook->api = api ? strdup(api) : NULL;
 538         hook->verb = verb ? strdup(verb) : NULL;
 539         hook->session = session ? ctxClientAddRef(session) : NULL;
 540
 541         if ((api && !hook->api) || (verb && !hook->verb)) {
 542                 free(hook->api);
 543                 free(hook->verb);
 544                 if (hook->session)
 545                         ctxClientUnref(hook->session);
 546                 free(hook);
 547                 return NULL;
 548         }
 549
 550         hook->refcount = 1;
 551         hook->flags = flags;
 552         hook->reqitf = itf ? itf : &hook_req_default_itf;
 553         hook->closure = closure;
 554
 555         hook->next = list_of_hooks;
 556         list_of_hooks = hook;
 557         return hook;
 558 }
 559
 560 struct afb_hook *afb_hook_addref(struct afb_hook *hook)
 561 {
 562         hook->refcount++;
 563         return hook;
 564 }
 565
 566 void afb_hook_unref(struct afb_hook *hook)
 567 {
 568         if (!--hook->refcount) {
 569                 /* unlink */
 570                 struct afb_hook **prv = &list_of_hooks;
 571                 while (*prv && *prv != hook)
 572                         prv = &(*prv)->next;
 573                 if(*prv)
 574                         *prv = hook->next;
 575
 576                 /* free */
 577                 free(hook->api);
 578                 free(hook->verb);
 579                 if (hook->session)
 580                         ctxClientUnref(hook->session);
 581                 free(hook);
 582         }
 583 }
 584