src/afb-hook.c

   1 /*
   2  * Copyright (C) 2016, 2017 "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 "afb-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_session *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, const char *verb)
 276 {
 277         int len;
 278         char name[257];
 279         unsigned id;
 280         struct afb_hook_req *tr;
 281
 282         /* get the call id */
 283         id = ++hook_count;
 284         if (id == 1000000)
 285                 id = hook_count = 1;
 286
 287         /* creates the name */
 288         len = snprintf(name, sizeof name, "%06d:%s/%s", id, api, verb);
 289         if (len < 0 || (size_t)len >= sizeof name) {
 290                 tr = NULL;
 291         } else {
 292                 tr = malloc(sizeof *tr + (size_t)len);
 293                 if (tr != NULL) {
 294                         /* init hook */
 295                         tr->observers = NULL;
 296                         tr->refcount = 1;
 297                         tr->context = context;
 298                         tr->req = req;
 299                         afb_req_addref(req);
 300                         memcpy(tr->name, name, (size_t)(len + 1));
 301                 }
 302         }
 303         return tr;
 304 }
 305
 306 static void hook_req_add_observer(struct afb_hook_req *tr, struct afb_hook *hook)
 307 {
 308         struct hook_req_observer *observer;
 309
 310         observer = malloc(sizeof *observer);
 311         if (observer) {
 312                 observer->hook = afb_hook_addref(hook);
 313                 observer->next = tr->observers;
 314                 tr->observers = observer;
 315         }
 316 }
 317
 318 /******************************************************************************
 319  * section: hooks for tracing requests
 320  *****************************************************************************/
 321
 322 static struct json_object *req_hook_json(void *closure)
 323 {
 324         struct afb_hook_req *tr = closure;
 325         struct json_object *r;
 326
 327         r = afb_req_json(tr->req);
 328         TRACE_REQ(json, tr, r);
 329         return r;
 330 }
 331
 332 static struct afb_arg req_hook_get(void *closure, const char *name)
 333 {
 334         struct afb_hook_req *tr = closure;
 335         struct afb_arg a;
 336
 337         a = afb_req_get(tr->req, name);
 338         TRACE_REQ(get, tr, name, a);
 339         return a;
 340 }
 341
 342 static void req_hook_success(void *closure, struct json_object *obj, const char *info)
 343 {
 344         struct afb_hook_req *tr = closure;
 345
 346         TRACE_REQ(success, tr, obj, info);
 347         afb_req_success(tr->req, obj, info);
 348         hook_req_unref(tr);
 349 }
 350
 351 static void req_hook_fail(void *closure, const char *status, const char *info)
 352 {
 353         struct afb_hook_req *tr = closure;
 354
 355         TRACE_REQ(fail, tr, status, info);
 356         afb_req_fail(tr->req, status, info);
 357         hook_req_unref(tr);
 358 }
 359
 360 static const char *req_hook_raw(void *closure, size_t *size)
 361 {
 362         struct afb_hook_req *tr = closure;
 363         const char *r;
 364         size_t s;
 365
 366         r = afb_req_raw(tr->req, &s);
 367         TRACE_REQ(raw, tr, r, s);
 368         if (size)
 369                 *size = s;
 370         return r;
 371 }
 372
 373 static void req_hook_send(void *closure, const char *buffer, size_t size)
 374 {
 375         struct afb_hook_req *tr = closure;
 376
 377         TRACE_REQ(send, tr, buffer, size);
 378         afb_req_send(tr->req, buffer, size);
 379 }
 380
 381 static void *req_hook_context_get(void *closure)
 382 {
 383         struct afb_hook_req *tr = closure;
 384         void *r;
 385
 386         r = afb_req_context_get(tr->req);
 387         TRACE_REQ(context_get, tr, r);
 388
 389         return r;
 390 }
 391
 392 static void req_hook_context_set(void *closure, void *value, void (*free_value)(void*))
 393 {
 394         struct afb_hook_req *tr = closure;
 395
 396         TRACE_REQ(context_set, tr, value, free_value);
 397         afb_req_context_set(tr->req, value, free_value);
 398 }
 399
 400 static void req_hook_addref(void *closure)
 401 {
 402         struct afb_hook_req *tr = closure;
 403
 404         TRACE_REQ_(addref, tr);
 405         hook_req_addref(tr);
 406 }
 407
 408 static void req_hook_unref(void *closure)
 409 {
 410         struct afb_hook_req *tr = closure;
 411
 412         TRACE_REQ_(unref, tr);
 413         hook_req_unref(tr);
 414 }
 415
 416 static void req_hook_session_close(void *closure)
 417 {
 418         struct afb_hook_req *tr = closure;
 419
 420         TRACE_REQ_(session_close, tr);
 421         afb_req_session_close(tr->req);
 422 }
 423
 424 static int req_hook_session_set_LOA(void *closure, unsigned level)
 425 {
 426         struct afb_hook_req *tr = closure;
 427         int r;
 428
 429         r = afb_req_session_set_LOA(tr->req, level);
 430         TRACE_REQ(session_set_LOA, tr, level, r);
 431         return r;
 432 }
 433
 434 static int req_hook_subscribe(void *closure, struct afb_event event)
 435 {
 436         struct afb_hook_req *tr = closure;
 437         int r;
 438
 439         r = afb_req_subscribe(tr->req, event);
 440         TRACE_REQ(subscribe, tr, event, r);
 441         return r;
 442 }
 443
 444 static int req_hook_unsubscribe(void *closure, struct afb_event event)
 445 {
 446         struct afb_hook_req *tr = closure;
 447         int r;
 448
 449         r = afb_req_unsubscribe(tr->req, event);
 450         TRACE_REQ(unsubscribe, tr, event, r);
 451         return r;
 452 }
 453
 454 static void req_hook_subcall_result(void *closure, int status, struct json_object *result)
 455 {
 456         struct hook_subcall *sc = closure;
 457         struct hook_subcall s = *sc;
 458
 459         free(sc);
 460         TRACE_REQ(subcall_result, s.tr, status, result);
 461         hook_req_unref(s.tr);
 462         s.callback(s.cb_closure, status, result);
 463 }
 464
 465 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)
 466 {
 467         struct afb_hook_req *tr = closure;
 468         struct hook_subcall *sc;
 469
 470         TRACE_REQ(subcall, tr, api, verb, args);
 471         sc = malloc(sizeof *sc);
 472         if (sc) {
 473                 sc->tr = tr;
 474                 sc->callback = callback;
 475                 sc->cb_closure = cb_closure;
 476                 hook_req_addref(tr);
 477                 cb_closure = sc;
 478                 callback = req_hook_subcall_result;
 479         }
 480         afb_req_subcall(tr->req, api, verb, args, callback, cb_closure);
 481 }
 482
 483 static struct afb_req_itf req_hook_itf = {
 484         .json = req_hook_json,
 485         .get = req_hook_get,
 486         .success = req_hook_success,
 487         .fail = req_hook_fail,
 488         .raw = req_hook_raw,
 489         .send = req_hook_send,
 490         .context_get = req_hook_context_get,
 491         .context_set = req_hook_context_set,
 492         .addref = req_hook_addref,
 493         .unref = req_hook_unref,
 494         .session_close = req_hook_session_close,
 495         .session_set_LOA = req_hook_session_set_LOA,
 496         .subscribe = req_hook_subscribe,
 497         .unsubscribe = req_hook_unsubscribe,
 498         .subcall = req_hook_subcall
 499 };
 500
 501 /******************************************************************************
 502  * section:
 503  *****************************************************************************/
 504
 505 struct afb_req afb_hook_req_call(struct afb_req req, struct afb_context *context, const char *api, const char *verb)
 506 {
 507         int add;
 508         struct afb_hook_req *tr;
 509         struct afb_hook *hook;
 510
 511         hook = list_of_hooks;
 512         if (hook) {
 513                 tr = NULL;
 514                 do {
 515                         add = (hook->flags & afb_hook_flags_req_all) != 0
 516                            && (!hook->session || hook->session == context->session)
 517                            && (!hook->api || !strcasecmp(hook->api, api))
 518                            && (!hook->verb || !strcasecmp(hook->verb, verb));
 519                         if (add) {
 520                                 if (!tr)
 521                                         tr = hook_req_create(req, context, api, verb);
 522                                 if (tr)
 523                                         hook_req_add_observer(tr, hook);
 524                         }
 525                         hook = hook->next;
 526                 } while(hook);
 527                 if (tr) {
 528                         req.closure = tr;
 529                         req.itf = &req_hook_itf;
 530                         TRACE_REQX(begin, tr);
 531                 }
 532         }
 533
 534         return req;
 535 }
 536
 537 struct afb_hook *afb_hook_req_create(const char *api, const char *verb, struct afb_session *session, unsigned flags, struct afb_hook_req_itf *itf, void *closure)
 538 {
 539         struct afb_hook *hook;
 540
 541         hook = malloc(sizeof *hook);
 542         if (hook == NULL)
 543                 return NULL;
 544
 545         hook->api = api ? strdup(api) : NULL;
 546         hook->verb = verb ? strdup(verb) : NULL;
 547         hook->session = session ? afb_session_addref(session) : NULL;
 548
 549         if ((api && !hook->api) || (verb && !hook->verb)) {
 550                 free(hook->api);
 551                 free(hook->verb);
 552                 if (hook->session)
 553                         afb_session_unref(hook->session);
 554                 free(hook);
 555                 return NULL;
 556         }
 557
 558         hook->refcount = 1;
 559         hook->flags = flags;
 560         hook->reqitf = itf ? itf : &hook_req_default_itf;
 561         hook->closure = closure;
 562
 563         hook->next = list_of_hooks;
 564         list_of_hooks = hook;
 565         return hook;
 566 }
 567
 568 struct afb_hook *afb_hook_addref(struct afb_hook *hook)
 569 {
 570         hook->refcount++;
 571         return hook;
 572 }
 573
 574 void afb_hook_unref(struct afb_hook *hook)
 575 {
 576         if (!--hook->refcount) {
 577                 /* unlink */
 578                 struct afb_hook **prv = &list_of_hooks;
 579                 while (*prv && *prv != hook)
 580                         prv = &(*prv)->next;
 581                 if(*prv)
 582                         *prv = hook->next;
 583
 584                 /* free */
 585                 free(hook->api);
 586                 free(hook->verb);
 587                 if (hook->session)
 588                         afb_session_unref(hook->session);
 589                 free(hook);
 590         }
 591 }
 592