src/bin/lttng-sessiond/agent.c

   1 /*
   2  * Copyright (C) 2013 - David Goulet <dgoulet@efficios.com>
   3  * Copyright (C) 2016 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License, version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  12  * more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along with
  15  * this program; if not, write to the Free Software Foundation, Inc., 51
  16  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #define _LGPL_SOURCE
  20 #include <assert.h>
  21 #include <urcu/uatomic.h>
  22 #include <urcu/rculist.h>
  23
  24 #include <common/common.h>
  25 #include <common/sessiond-comm/agent.h>
  26
  27 #include <common/compat/endian.h>
  28
  29 #include "agent.h"
  30 #include "ust-app.h"
  31 #include "utils.h"
  32 #include "error.h"
  33
  34 #define AGENT_RET_CODE_INDEX(code) (code - AGENT_RET_CODE_SUCCESS)
  35
  36 /*
  37  * Agent application context representation.
  38  */
  39 struct agent_app_ctx {
  40         char *provider_name;
  41         char *ctx_name;
  42
  43         /* agent_app_ctx are part of the agent app_ctx_list. */
  44         struct cds_list_head list_node;
  45
  46         /* For call_rcu teardown. */
  47         struct rcu_head rcu_node;
  48 };
  49
  50 /*
  51  * Human readable agent return code.
  52  */
  53 static const char *error_string_array[] = {
  54         [ AGENT_RET_CODE_INDEX(AGENT_RET_CODE_SUCCESS) ] = "Success",
  55         [ AGENT_RET_CODE_INDEX(AGENT_RET_CODE_INVALID) ] = "Invalid command",
  56         [ AGENT_RET_CODE_INDEX(AGENT_RET_CODE_UNKNOWN_NAME) ] = "Unknown logger name",
  57
  58         /* Last element */
  59         [ AGENT_RET_CODE_INDEX(AGENT_RET_CODE_NR) ] = "Unknown code",
  60 };
  61
  62 static
  63 void log_reply_code(uint32_t in_reply_ret_code)
  64 {
  65         int level = PRINT_DBG3;
  66         /*
  67          * reply_ret_code and in_reply_ret_code are kept separate to have a
  68          * sanitized value (used to retrieve the human readable string) and the
  69          * original value which is logged as-is.
  70          */
  71         uint32_t reply_ret_code = in_reply_ret_code;
  72
  73         if (reply_ret_code < AGENT_RET_CODE_SUCCESS ||
  74                         reply_ret_code >= AGENT_RET_CODE_NR) {
  75                 reply_ret_code = AGENT_RET_CODE_NR;
  76                 level = PRINT_ERR;
  77         }
  78
  79         LOG(level, "Agent replied with retcode: %s (%"PRIu32")",
  80                         error_string_array[AGENT_RET_CODE_INDEX(
  81                         reply_ret_code)],
  82                         in_reply_ret_code);
  83 }
  84
  85 /*
  86  * Match function for the events hash table lookup by name.
  87  */
  88 static int ht_match_event_by_name(struct cds_lfht_node *node,
  89                 const void *_key)
  90 {
  91         struct agent_event *event;
  92         const struct agent_ht_key *key;
  93
  94         assert(node);
  95         assert(_key);
  96
  97         event = caa_container_of(node, struct agent_event, node.node);
  98         key = _key;
  99
 100         /* Match 1 elements of the key: name. */
 101
 102         /* Event name */
 103         if (strncmp(event->name, key->name, sizeof(event->name)) != 0) {
 104                 goto no_match;
 105         }
 106         /* Match. */
 107         return 1;
 108
 109 no_match:
 110         return 0;
 111 }
 112
 113 /*
 114  * Match function for the events hash table lookup by name and loglevel.
 115  */
 116 static int ht_match_event(struct cds_lfht_node *node,
 117                 const void *_key)
 118 {
 119         struct agent_event *event;
 120         const struct agent_ht_key *key;
 121         int ll_match;
 122
 123         assert(node);
 124         assert(_key);
 125
 126         event = caa_container_of(node, struct agent_event, node.node);
 127         key = _key;
 128
 129         /* Match 2 elements of the key: name and loglevel. */
 130
 131         /* Event name */
 132         if (strncmp(event->name, key->name, sizeof(event->name)) != 0) {
 133                 goto no_match;
 134         }
 135
 136         /* Event loglevel value and type. */
 137         ll_match = loglevels_match(event->loglevel_type,
 138                 event->loglevel_value, key->loglevel_type,
 139                 key->loglevel_value, LTTNG_EVENT_LOGLEVEL_ALL);
 140
 141         if (!ll_match) {
 142                 goto no_match;
 143         }
 144
 145         /* Filter expression */
 146         if (strncmp(event->filter_expression, key->filter_expression,
 147                         strlen(event->filter_expression)) != 0) {
 148                 goto no_match;
 149         }
 150
 151         return 1;
 152
 153 no_match:
 154         return 0;
 155 }
 156
 157 /*
 158  * Add unique agent event based on the event name and loglevel.
 159  */
 160 static void add_unique_agent_event(struct lttng_ht *ht,
 161                 struct agent_event *event)
 162 {
 163         struct cds_lfht_node *node_ptr;
 164         struct agent_ht_key key;
 165
 166         assert(ht);
 167         assert(ht->ht);
 168         assert(event);
 169
 170         key.name = event->name;
 171         key.loglevel_value = event->loglevel_value;
 172         key.loglevel_type = event->loglevel_type;
 173         key.filter_expression = event->filter_expression;
 174
 175         node_ptr = cds_lfht_add_unique(ht->ht,
 176                         ht->hash_fct(event->node.key, lttng_ht_seed),
 177                         ht_match_event, &key, &event->node.node);
 178         assert(node_ptr == &event->node.node);
 179 }
 180
 181 /*
 182  * URCU delayed agent event reclaim.
 183  */
 184 static void destroy_event_agent_rcu(struct rcu_head *head)
 185 {
 186         struct lttng_ht_node_str *node =
 187                 caa_container_of(head, struct lttng_ht_node_str, head);
 188         struct agent_event *event =
 189                 caa_container_of(node, struct agent_event, node);
 190
 191         agent_destroy_event(event);
 192 }
 193
 194 /*
 195  * URCU delayed agent app reclaim.
 196  */
 197 static void destroy_app_agent_rcu(struct rcu_head *head)
 198 {
 199         struct lttng_ht_node_ulong *node =
 200                 caa_container_of(head, struct lttng_ht_node_ulong, head);
 201         struct agent_app *app =
 202                 caa_container_of(node, struct agent_app, node);
 203
 204         free(app);
 205 }
 206
 207 /*
 208  * Communication with the agent. Send the message header to the given socket in
 209  * big endian.
 210  *
 211  * Return 0 on success or else a negative errno message of sendmsg() op.
 212  */
 213 static int send_header(struct lttcomm_sock *sock, uint64_t data_size,
 214                 uint32_t cmd, uint32_t cmd_version)
 215 {
 216         int ret;
 217         ssize_t size;
 218         struct lttcomm_agent_hdr msg;
 219
 220         assert(sock);
 221
 222         memset(&msg, 0, sizeof(msg));
 223         msg.data_size = htobe64(data_size);
 224         msg.cmd = htobe32(cmd);
 225         msg.cmd_version = htobe32(cmd_version);
 226
 227         size = sock->ops->sendmsg(sock, &msg, sizeof(msg), 0);
 228         if (size < sizeof(msg)) {
 229                 ret = -errno;
 230                 goto error;
 231         }
 232         ret = 0;
 233
 234 error:
 235         return ret;
 236 }
 237
 238 /*
 239  * Communication call with the agent. Send the payload to the given socket. The
 240  * header MUST be sent prior to this call.
 241  *
 242  * Return 0 on success or else a negative errno value of sendmsg() op.
 243  */
 244 static int send_payload(struct lttcomm_sock *sock, const void *data,
 245                 size_t size)
 246 {
 247         int ret;
 248         ssize_t len;
 249
 250         assert(sock);
 251         assert(data);
 252
 253         len = sock->ops->sendmsg(sock, data, size, 0);
 254         if (len < size) {
 255                 ret = -errno;
 256                 goto error;
 257         }
 258         ret = 0;
 259
 260 error:
 261         return ret;
 262 }
 263
 264 /*
 265  * Communication call with the agent. Receive reply from the agent using the
 266  * given socket.
 267  *
 268  * Return 0 on success or else a negative errno value from recvmsg() op.
 269  */
 270 static int recv_reply(struct lttcomm_sock *sock, void *buf, size_t size)
 271 {
 272         int ret;
 273         ssize_t len;
 274
 275         assert(sock);
 276         assert(buf);
 277
 278         len = sock->ops->recvmsg(sock, buf, size, 0);
 279         if (len < size) {
 280                 ret = -errno;
 281                 goto error;
 282         }
 283         ret = 0;
 284
 285 error:
 286         return ret;
 287 }
 288
 289 /*
 290  * Internal event listing for a given app. Populate events.
 291  *
 292  * Return number of element in the list or else a negative LTTNG_ERR* code.
 293  * On success, the caller is responsible for freeing the memory
 294  * allocated for "events".
 295  */
 296 static ssize_t list_events(struct agent_app *app, struct lttng_event **events)
 297 {
 298         int ret, i, len = 0, offset = 0;
 299         uint32_t nb_event;
 300         size_t data_size;
 301         uint32_t reply_ret_code;
 302         struct lttng_event *tmp_events = NULL;
 303         struct lttcomm_agent_list_reply *reply = NULL;
 304         struct lttcomm_agent_list_reply_hdr reply_hdr;
 305
 306         assert(app);
 307         assert(app->sock);
 308         assert(events);
 309
 310         DBG2("Agent listing events for app pid: %d and socket %d", app->pid,
 311                         app->sock->fd);
 312
 313         ret = send_header(app->sock, 0, AGENT_CMD_LIST, 0);
 314         if (ret < 0) {
 315                 goto error_io;
 316         }
 317
 318         /* Get list header so we know how much we'll receive. */
 319         ret = recv_reply(app->sock, &reply_hdr, sizeof(reply_hdr));
 320         if (ret < 0) {
 321                 goto error_io;
 322         }
 323
 324         reply_ret_code = be32toh(reply_hdr.ret_code);
 325         log_reply_code(reply_ret_code);
 326         switch (reply_ret_code) {
 327         case AGENT_RET_CODE_SUCCESS:
 328                 data_size = be32toh(reply_hdr.data_size) + sizeof(*reply);
 329                 break;
 330         default:
 331                 ret = LTTNG_ERR_UNK;
 332                 goto error;
 333         }
 334
 335         reply = zmalloc(data_size);
 336         if (!reply) {
 337                 ret = LTTNG_ERR_NOMEM;
 338                 goto error;
 339         }
 340
 341         /* Get the list with the appropriate data size. */
 342         ret = recv_reply(app->sock, reply, data_size);
 343         if (ret < 0) {
 344                 goto error_io;
 345         }
 346
 347         nb_event = be32toh(reply->nb_event);
 348         tmp_events = zmalloc(sizeof(*tmp_events) * nb_event);
 349         if (!tmp_events) {
 350                 ret = LTTNG_ERR_NOMEM;
 351                 goto error;
 352         }
 353
 354         for (i = 0; i < nb_event; i++) {
 355                 offset += len;
 356                 strncpy(tmp_events[i].name, reply->payload + offset,
 357                                 sizeof(tmp_events[i].name));
 358                 tmp_events[i].pid = app->pid;
 359                 tmp_events[i].enabled = -1;
 360                 len = strlen(reply->payload + offset) + 1;
 361         }
 362
 363         *events = tmp_events;
 364
 365         free(reply);
 366         return nb_event;
 367
 368 error_io:
 369         ret = LTTNG_ERR_UST_LIST_FAIL;
 370 error:
 371         free(reply);
 372         free(tmp_events);
 373         return -ret;
 374
 375 }
 376
 377 /*
 378  * Internal enable agent event on a agent application. This function
 379  * communicates with the agent to enable a given event.
 380  *
 381  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 382  */
 383 static int enable_event(struct agent_app *app, struct agent_event *event)
 384 {
 385         int ret;
 386         char *bytes_to_send;
 387         uint64_t data_size;
 388         size_t filter_expression_length;
 389         uint32_t reply_ret_code;
 390         struct lttcomm_agent_enable_event msg;
 391         struct lttcomm_agent_generic_reply reply;
 392
 393         assert(app);
 394         assert(app->sock);
 395         assert(event);
 396
 397         DBG2("Agent enabling event %s for app pid: %d and socket %d", event->name,
 398                         app->pid, app->sock->fd);
 399
 400         /*
 401          * Calculate the payload's size, which is the fixed-size struct followed
 402          * by the variable-length filter expression (+1 for the ending \0).
 403          */
 404         if (!event->filter_expression) {
 405                 filter_expression_length = 0;
 406         } else {
 407                 filter_expression_length = strlen(event->filter_expression) + 1;
 408         }
 409         data_size = sizeof(msg) + filter_expression_length;
 410
 411         ret = send_header(app->sock, data_size, AGENT_CMD_ENABLE, 0);
 412         if (ret < 0) {
 413                 goto error_io;
 414         }
 415
 416         memset(&msg, 0, sizeof(msg));
 417         msg.loglevel_value = htobe32(event->loglevel_value);
 418         msg.loglevel_type = htobe32(event->loglevel_type);
 419         strncpy(msg.name, event->name, sizeof(msg.name));
 420         msg.filter_expression_length = htobe32(filter_expression_length);
 421
 422         bytes_to_send = zmalloc(data_size);
 423         if (!bytes_to_send) {
 424                 ret = LTTNG_ERR_NOMEM;
 425                 goto error;
 426         }
 427
 428         memcpy(bytes_to_send, &msg, sizeof(msg));
 429         if (filter_expression_length > 0) {
 430                 memcpy(bytes_to_send + sizeof(msg), event->filter_expression,
 431                                 filter_expression_length);
 432         }
 433
 434         ret = send_payload(app->sock, bytes_to_send, data_size);
 435         free(bytes_to_send);
 436         if (ret < 0) {
 437                 goto error_io;
 438         }
 439
 440         ret = recv_reply(app->sock, &reply, sizeof(reply));
 441         if (ret < 0) {
 442                 goto error_io;
 443         }
 444
 445         reply_ret_code = be32toh(reply.ret_code);
 446         log_reply_code(reply_ret_code);
 447         switch (reply_ret_code) {
 448         case AGENT_RET_CODE_SUCCESS:
 449                 break;
 450         case AGENT_RET_CODE_UNKNOWN_NAME:
 451                 ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
 452                 goto error;
 453         default:
 454                 ret = LTTNG_ERR_UNK;
 455                 goto error;
 456         }
 457
 458         return LTTNG_OK;
 459
 460 error_io:
 461         ret = LTTNG_ERR_UST_ENABLE_FAIL;
 462 error:
 463         return ret;
 464 }
 465
 466 /*
 467  * Send Pascal-style string. Size is sent as a 32-bit big endian integer.
 468  */
 469 static
 470 int send_pstring(struct lttcomm_sock *sock, const char *str, uint32_t len)
 471 {
 472         int ret;
 473         uint32_t len_be;
 474
 475         len_be = htobe32(len);
 476         ret = send_payload(sock, &len_be, sizeof(len_be));
 477         if (ret) {
 478                 goto end;
 479         }
 480
 481         ret = send_payload(sock, str, len);
 482         if (ret) {
 483                 goto end;
 484         }
 485 end:
 486         return ret;
 487 }
 488
 489 /*
 490  * Internal enable application context on an agent application. This function
 491  * communicates with the agent to enable a given application context.
 492  *
 493  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 494  */
 495 static int app_context_op(struct agent_app *app,
 496                 struct agent_app_ctx *ctx, enum lttcomm_agent_command cmd)
 497 {
 498         int ret;
 499         uint32_t reply_ret_code;
 500         struct lttcomm_agent_generic_reply reply;
 501         size_t app_ctx_provider_name_len, app_ctx_name_len, data_size;
 502
 503         assert(app);
 504         assert(app->sock);
 505         assert(ctx);
 506         assert(cmd == AGENT_CMD_APP_CTX_ENABLE ||
 507                         cmd == AGENT_CMD_APP_CTX_DISABLE);
 508
 509         DBG2("Agent %s application %s:%s for app pid: %d and socket %d",
 510                         cmd == AGENT_CMD_APP_CTX_ENABLE ? "enabling" : "disabling",
 511                         ctx->provider_name, ctx->ctx_name,
 512                         app->pid, app->sock->fd);
 513
 514         /*
 515          * Calculate the payload's size, which consists of the size (u32, BE)
 516          * of the provider name, the NULL-terminated provider name string, the
 517          * size (u32, BE) of the context name, followed by the NULL-terminated
 518          * context name string.
 519          */
 520         app_ctx_provider_name_len = strlen(ctx->provider_name) + 1;
 521         app_ctx_name_len = strlen(ctx->ctx_name) + 1;
 522         data_size = sizeof(uint32_t) + app_ctx_provider_name_len +
 523                         sizeof(uint32_t) + app_ctx_name_len;
 524
 525         ret = send_header(app->sock, data_size, cmd, 0);
 526         if (ret < 0) {
 527                 goto error_io;
 528         }
 529
 530         if (app_ctx_provider_name_len > UINT32_MAX ||
 531                         app_ctx_name_len > UINT32_MAX) {
 532                 ERR("Application context name > MAX_UINT32");
 533                 ret = LTTNG_ERR_INVALID;
 534                 goto error;
 535         }
 536
 537         ret = send_pstring(app->sock, ctx->provider_name,
 538                         (uint32_t) app_ctx_provider_name_len);
 539         if (ret < 0) {
 540                 goto error_io;
 541         }
 542
 543         ret = send_pstring(app->sock, ctx->ctx_name,
 544                         (uint32_t) app_ctx_name_len);
 545         if (ret < 0) {
 546                 goto error_io;
 547         }
 548
 549         ret = recv_reply(app->sock, &reply, sizeof(reply));
 550         if (ret < 0) {
 551                 goto error_io;
 552         }
 553
 554         reply_ret_code = be32toh(reply.ret_code);
 555         log_reply_code(reply_ret_code);
 556         switch (reply_ret_code) {
 557         case AGENT_RET_CODE_SUCCESS:
 558                 break;
 559         default:
 560                 ret = LTTNG_ERR_UNK;
 561                 goto error;
 562         }
 563
 564         return LTTNG_OK;
 565
 566 error_io:
 567         ret = LTTNG_ERR_UST_ENABLE_FAIL;
 568 error:
 569         return ret;
 570 }
 571
 572 /*
 573  * Internal disable agent event call on a agent application. This function
 574  * communicates with the agent to disable a given event.
 575  *
 576  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 577  */
 578 static int disable_event(struct agent_app *app, struct agent_event *event)
 579 {
 580         int ret;
 581         uint64_t data_size;
 582         uint32_t reply_ret_code;
 583         struct lttcomm_agent_disable_event msg;
 584         struct lttcomm_agent_generic_reply reply;
 585
 586         assert(app);
 587         assert(app->sock);
 588         assert(event);
 589
 590         DBG2("Agent disabling event %s for app pid: %d and socket %d", event->name,
 591                         app->pid, app->sock->fd);
 592
 593         data_size = sizeof(msg);
 594
 595         ret = send_header(app->sock, data_size, AGENT_CMD_DISABLE, 0);
 596         if (ret < 0) {
 597                 goto error_io;
 598         }
 599
 600         memset(&msg, 0, sizeof(msg));
 601         strncpy(msg.name, event->name, sizeof(msg.name));
 602         ret = send_payload(app->sock, &msg, sizeof(msg));
 603         if (ret < 0) {
 604                 goto error_io;
 605         }
 606
 607         ret = recv_reply(app->sock, &reply, sizeof(reply));
 608         if (ret < 0) {
 609                 goto error_io;
 610         }
 611
 612         reply_ret_code = be32toh(reply.ret_code);
 613         log_reply_code(reply_ret_code);
 614         switch (reply_ret_code) {
 615         case AGENT_RET_CODE_SUCCESS:
 616                 break;
 617         case AGENT_RET_CODE_UNKNOWN_NAME:
 618                 ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
 619                 goto error;
 620         default:
 621                 ret = LTTNG_ERR_UNK;
 622                 goto error;
 623         }
 624
 625         return LTTNG_OK;
 626
 627 error_io:
 628         ret = LTTNG_ERR_UST_DISABLE_FAIL;
 629 error:
 630         return ret;
 631 }
 632
 633 /*
 634  * Send back the registration DONE command to a given agent application.
 635  *
 636  * Return 0 on success or else a negative value.
 637  */
 638 int agent_send_registration_done(struct agent_app *app)
 639 {
 640         assert(app);
 641         assert(app->sock);
 642
 643         DBG("Agent sending registration done to app socket %d", app->sock->fd);
 644
 645         return send_header(app->sock, 0, AGENT_CMD_REG_DONE, 0);
 646 }
 647
 648 /*
 649  * Enable agent event on every agent applications registered with the session
 650  * daemon.
 651  *
 652  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 653  */
 654 int agent_enable_event(struct agent_event *event,
 655                 enum lttng_domain_type domain)
 656 {
 657         int ret;
 658         struct agent_app *app;
 659         struct lttng_ht_iter iter;
 660
 661         assert(event);
 662
 663         rcu_read_lock();
 664
 665         cds_lfht_for_each_entry(agent_apps_ht_by_sock->ht, &iter.iter, app,
 666                         node.node) {
 667                 if (app->domain != domain) {
 668                         continue;
 669                 }
 670
 671                 /* Enable event on agent application through TCP socket. */
 672                 ret = enable_event(app, event);
 673                 if (ret != LTTNG_OK) {
 674                         goto error;
 675                 }
 676         }
 677
 678         event->enabled = 1;
 679         ret = LTTNG_OK;
 680
 681 error:
 682         rcu_read_unlock();
 683         return ret;
 684 }
 685
 686 static
 687 void destroy_app_ctx(struct agent_app_ctx *ctx)
 688 {
 689         free(ctx->provider_name);
 690         free(ctx->ctx_name);
 691         free(ctx);
 692 }
 693
 694 static
 695 struct agent_app_ctx *create_app_ctx(struct lttng_event_context *ctx)
 696 {
 697         struct agent_app_ctx *agent_ctx = NULL;
 698
 699         if (!ctx) {
 700                 goto end;
 701         }
 702
 703         assert(ctx->ctx == LTTNG_EVENT_CONTEXT_APP_CONTEXT);
 704         agent_ctx = zmalloc(sizeof(*ctx));
 705         if (!agent_ctx) {
 706                 goto end;
 707         }
 708
 709         agent_ctx->provider_name = strdup(ctx->u.app_ctx.provider_name);
 710         agent_ctx->ctx_name = strdup(ctx->u.app_ctx.ctx_name);
 711         if (!agent_ctx->provider_name || !agent_ctx->ctx_name) {
 712                 destroy_app_ctx(agent_ctx);
 713                 agent_ctx = NULL;
 714         }
 715 end:
 716         return agent_ctx;
 717 }
 718
 719 /*
 720  * Enable agent context on every agent applications registered with the session
 721  * daemon.
 722  *
 723  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 724  */
 725 int agent_enable_context(struct lttng_event_context *ctx,
 726                 enum lttng_domain_type domain)
 727 {
 728         int ret;
 729         struct agent_app *app;
 730         struct lttng_ht_iter iter;
 731
 732         assert(ctx);
 733         if (ctx->ctx != LTTNG_EVENT_CONTEXT_APP_CONTEXT) {
 734                 ret = LTTNG_ERR_INVALID;
 735                 goto error;
 736         }
 737
 738         rcu_read_lock();
 739
 740         cds_lfht_for_each_entry(agent_apps_ht_by_sock->ht, &iter.iter, app,
 741                         node.node) {
 742                 struct agent_app_ctx *agent_ctx;
 743
 744                 if (app->domain != domain) {
 745                         continue;
 746                 }
 747
 748                 agent_ctx = create_app_ctx(ctx);
 749                 if (!agent_ctx) {
 750                         ret = LTTNG_ERR_NOMEM;
 751                         goto error_unlock;
 752                 }
 753
 754                 /* Enable event on agent application through TCP socket. */
 755                 ret = app_context_op(app, agent_ctx, AGENT_CMD_APP_CTX_ENABLE);
 756                 destroy_app_ctx(agent_ctx);
 757                 if (ret != LTTNG_OK) {
 758                         goto error_unlock;
 759                 }
 760         }
 761
 762         ret = LTTNG_OK;
 763
 764 error_unlock:
 765         rcu_read_unlock();
 766 error:
 767         return ret;
 768 }
 769
 770 /*
 771  * Disable agent event on every agent application registered with the session
 772  * daemon.
 773  *
 774  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 775  */
 776 int agent_disable_event(struct agent_event *event,
 777                 enum lttng_domain_type domain)
 778 {
 779         int ret = LTTNG_OK;
 780         struct agent_app *app;
 781         struct lttng_ht_iter iter;
 782
 783         assert(event);
 784         if (!event->enabled) {
 785                 goto end;
 786         }
 787
 788         rcu_read_lock();
 789
 790         cds_lfht_for_each_entry(agent_apps_ht_by_sock->ht, &iter.iter, app,
 791                         node.node) {
 792                 if (app->domain != domain) {
 793                         continue;
 794                 }
 795
 796                 /* Enable event on agent application through TCP socket. */
 797                 ret = disable_event(app, event);
 798                 if (ret != LTTNG_OK) {
 799                         goto error;
 800                 }
 801         }
 802
 803         event->enabled = 0;
 804
 805 error:
 806         rcu_read_unlock();
 807 end:
 808         return ret;
 809 }
 810
 811 /*
 812  * Disable agent context on every agent application registered with the session
 813  * daemon.
 814  *
 815  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 816  */
 817 int disable_context(struct agent_app_ctx *ctx, enum lttng_domain_type domain)
 818 {
 819         int ret = LTTNG_OK;
 820         struct agent_app *app;
 821         struct lttng_ht_iter iter;
 822
 823         assert(ctx);
 824
 825         rcu_read_lock();
 826         DBG2("Disabling agent application context %s:%s",
 827                         ctx->provider_name, ctx->ctx_name);
 828         cds_lfht_for_each_entry(agent_apps_ht_by_sock->ht, &iter.iter, app,
 829                         node.node) {
 830                 if (app->domain != domain) {
 831                         continue;
 832                 }
 833
 834                 ret = app_context_op(app, ctx, AGENT_CMD_APP_CTX_DISABLE);
 835                 if (ret != LTTNG_OK) {
 836                         goto end;
 837                 }
 838         }
 839 end:
 840         rcu_read_unlock();
 841         return ret;
 842 }
 843
 844 /*
 845  * Ask every agent for the list of possible event. Events is allocated with the
 846  * events of every agent application.
 847  *
 848  * Return the number of events or else a negative value.
 849  */
 850 int agent_list_events(struct lttng_event **events,
 851                 enum lttng_domain_type domain)
 852 {
 853         int ret;
 854         size_t nbmem, count = 0;
 855         struct agent_app *app;
 856         struct lttng_event *tmp_events = NULL;
 857         struct lttng_ht_iter iter;
 858
 859         assert(events);
 860
 861         DBG2("Agent listing events for domain %d", domain);
 862
 863         nbmem = UST_APP_EVENT_LIST_SIZE;
 864         tmp_events = zmalloc(nbmem * sizeof(*tmp_events));
 865         if (!tmp_events) {
 866                 PERROR("zmalloc agent list events");
 867                 ret = -ENOMEM;
 868                 goto error;
 869         }
 870
 871         rcu_read_lock();
 872         cds_lfht_for_each_entry(agent_apps_ht_by_sock->ht, &iter.iter, app,
 873                         node.node) {
 874                 ssize_t nb_ev;
 875                 struct lttng_event *agent_events;
 876
 877                 /* Skip domain not asked by the list. */
 878                 if (app->domain != domain) {
 879                         continue;
 880                 }
 881
 882                 nb_ev = list_events(app, &agent_events);
 883                 if (nb_ev < 0) {
 884                         ret = nb_ev;
 885                         goto error_unlock;
 886                 }
 887
 888                 if (count + nb_ev > nbmem) {
 889                         /* In case the realloc fails, we free the memory */
 890                         struct lttng_event *new_tmp_events;
 891                         size_t new_nbmem;
 892
 893                         new_nbmem = max_t(size_t, count + nb_ev, nbmem << 1);
 894                         DBG2("Reallocating agent event list from %zu to %zu entries",
 895                                         nbmem, new_nbmem);
 896                         new_tmp_events = realloc(tmp_events,
 897                                 new_nbmem * sizeof(*new_tmp_events));
 898                         if (!new_tmp_events) {
 899                                 PERROR("realloc agent events");
 900                                 ret = -ENOMEM;
 901                                 free(agent_events);
 902                                 goto error_unlock;
 903                         }
 904                         /* Zero the new memory */
 905                         memset(new_tmp_events + nbmem, 0,
 906                                 (new_nbmem - nbmem) * sizeof(*new_tmp_events));
 907                         nbmem = new_nbmem;
 908                         tmp_events = new_tmp_events;
 909                 }
 910                 memcpy(tmp_events + count, agent_events,
 911                         nb_ev * sizeof(*tmp_events));
 912                 free(agent_events);
 913                 count += nb_ev;
 914         }
 915         rcu_read_unlock();
 916
 917         ret = count;
 918         *events = tmp_events;
 919         return ret;
 920
 921 error_unlock:
 922         rcu_read_unlock();
 923 error:
 924         free(tmp_events);
 925         return ret;
 926 }
 927
 928 /*
 929  * Create a agent app object using the given PID.
 930  *
 931  * Return newly allocated object or else NULL on error.
 932  */
 933 struct agent_app *agent_create_app(pid_t pid, enum lttng_domain_type domain,
 934                 struct lttcomm_sock *sock)
 935 {
 936         struct agent_app *app;
 937
 938         assert(sock);
 939
 940         app = zmalloc(sizeof(*app));
 941         if (!app) {
 942                 PERROR("zmalloc agent create");
 943                 goto error;
 944         }
 945
 946         app->pid = pid;
 947         app->domain = domain;
 948         app->sock = sock;
 949         lttng_ht_node_init_ulong(&app->node, (unsigned long) app->sock->fd);
 950
 951 error:
 952         return app;
 953 }
 954
 955 /*
 956  * Lookup agent app by socket in the global hash table.
 957  *
 958  * RCU read side lock MUST be acquired.
 959  *
 960  * Return object if found else NULL.
 961  */
 962 struct agent_app *agent_find_app_by_sock(int sock)
 963 {
 964         struct lttng_ht_node_ulong *node;
 965         struct lttng_ht_iter iter;
 966         struct agent_app *app;
 967
 968         assert(sock >= 0);
 969
 970         lttng_ht_lookup(agent_apps_ht_by_sock, (void *)((unsigned long) sock), &iter);
 971         node = lttng_ht_iter_get_node_ulong(&iter);
 972         if (node == NULL) {
 973                 goto error;
 974         }
 975         app = caa_container_of(node, struct agent_app, node);
 976
 977         DBG3("Agent app pid %d found by sock %d.", app->pid, sock);
 978         return app;
 979
 980 error:
 981         DBG3("Agent app NOT found by sock %d.", sock);
 982         return NULL;
 983 }
 984
 985 /*
 986  * Add agent application object to the global hash table.
 987  */
 988 void agent_add_app(struct agent_app *app)
 989 {
 990         assert(app);
 991
 992         DBG3("Agent adding app sock: %d and pid: %d to ht", app->sock->fd, app->pid);
 993         lttng_ht_add_unique_ulong(agent_apps_ht_by_sock, &app->node);
 994 }
 995
 996 /*
 997  * Delete agent application from the global hash table.
 998  *
 999  * rcu_read_lock() must be held by the caller.
1000  */
1001 void agent_delete_app(struct agent_app *app)
1002 {
1003         int ret;
1004         struct lttng_ht_iter iter;
1005
1006         assert(app);
1007
1008         DBG3("Agent deleting app pid: %d and sock: %d", app->pid, app->sock->fd);
1009
1010         iter.iter.node = &app->node.node;
1011         ret = lttng_ht_del(agent_apps_ht_by_sock, &iter);
1012         assert(!ret);
1013 }
1014
1015 /*
1016  * Destroy an agent application object by detaching it from its corresponding
1017  * UST app if one is connected by closing the socket. Finally, perform a
1018  * delayed memory reclaim.
1019  */
1020 void agent_destroy_app(struct agent_app *app)
1021 {
1022         assert(app);
1023
1024         if (app->sock) {
1025                 app->sock->ops->close(app->sock);
1026                 lttcomm_destroy_sock(app->sock);
1027         }
1028
1029         call_rcu(&app->node.head, destroy_app_agent_rcu);
1030 }
1031
1032 /*
1033  * Initialize an already allocated agent object.
1034  *
1035  * Return 0 on success or else a negative errno value.
1036  */
1037 int agent_init(struct agent *agt)
1038 {
1039         int ret;
1040
1041         assert(agt);
1042
1043         agt->events = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
1044         if (!agt->events) {
1045                 ret = -ENOMEM;
1046                 goto error;
1047         }
1048         lttng_ht_node_init_u64(&agt->node, agt->domain);
1049
1050         CDS_INIT_LIST_HEAD(&agt->app_ctx_list);
1051         return 0;
1052
1053 error:
1054         return ret;
1055 }
1056
1057 /*
1058  * Add agent object to the given hash table.
1059  */
1060 void agent_add(struct agent *agt, struct lttng_ht *ht)
1061 {
1062         assert(agt);
1063         assert(ht);
1064
1065         DBG3("Agent adding from domain %d", agt->domain);
1066
1067         lttng_ht_add_unique_u64(ht, &agt->node);
1068 }
1069
1070 /*
1071  * Create an agent object for the given domain.
1072  *
1073  * Return the allocated agent or NULL on error.
1074  */
1075 struct agent *agent_create(enum lttng_domain_type domain)
1076 {
1077         int ret;
1078         struct agent *agt;
1079
1080         agt = zmalloc(sizeof(struct agent));
1081         if (!agt) {
1082                 goto error;
1083         }
1084         agt->domain = domain;
1085
1086         ret = agent_init(agt);
1087         if (ret < 0) {
1088                 free(agt);
1089                 agt = NULL;
1090                 goto error;
1091         }
1092
1093 error:
1094         return agt;
1095 }
1096
1097 /*
1098  * Create a newly allocated agent event data structure.
1099  * Ownership of filter_expression is taken.
1100  *
1101  * Return a new object else NULL on error.
1102  */
1103 struct agent_event *agent_create_event(const char *name,
1104                 enum lttng_loglevel_type loglevel_type, int loglevel_value,
1105                 struct lttng_filter_bytecode *filter, char *filter_expression)
1106 {
1107         struct agent_event *event = NULL;
1108
1109         DBG3("Agent create new event with name %s, loglevel type %d, \
1110                         loglevel value %d and filter %s",
1111                         name, loglevel_type, loglevel_value,
1112                         filter_expression ? filter_expression : "NULL");
1113
1114         if (!name) {
1115                 ERR("Failed to create agent event; no name provided.");
1116                 goto error;
1117         }
1118
1119         event = zmalloc(sizeof(*event));
1120         if (!event) {
1121                 goto error;
1122         }
1123
1124         strncpy(event->name, name, sizeof(event->name));
1125         event->name[sizeof(event->name) - 1] = '\0';
1126         lttng_ht_node_init_str(&event->node, event->name);
1127
1128         event->loglevel_value = loglevel_value;
1129         event->loglevel_type = loglevel_type;
1130         event->filter = filter;
1131         event->filter_expression = filter_expression;
1132 error:
1133         return event;
1134 }
1135
1136 /*
1137  * Unique add of a agent event to an agent object.
1138  */
1139 void agent_add_event(struct agent_event *event, struct agent *agt)
1140 {
1141         assert(event);
1142         assert(agt);
1143         assert(agt->events);
1144
1145         DBG3("Agent adding event %s", event->name);
1146         add_unique_agent_event(agt->events, event);
1147         agt->being_used = 1;
1148 }
1149
1150 /*
1151  * Unique add of a agent context to an agent object.
1152  */
1153 int agent_add_context(struct lttng_event_context *ctx, struct agent *agt)
1154 {
1155         int ret = LTTNG_OK;
1156         struct agent_app_ctx *agent_ctx = NULL;
1157
1158         assert(ctx);
1159         assert(agt);
1160         assert(agt->events);
1161         assert(ctx->ctx == LTTNG_EVENT_CONTEXT_APP_CONTEXT);
1162
1163         agent_ctx = create_app_ctx(ctx);
1164         if (!agent_ctx) {
1165                 ret = LTTNG_ERR_NOMEM;
1166                 goto end;
1167         }
1168
1169         DBG3("Agent adding context %s:%s", ctx->u.app_ctx.provider_name,
1170                         ctx->u.app_ctx.ctx_name);
1171         cds_list_add_tail_rcu(&agent_ctx->list_node, &agt->app_ctx_list);
1172 end:
1173         return ret;
1174 }
1175
1176 /*
1177  * Find multiple agent events sharing the given name.
1178  *
1179  * RCU read side lock MUST be acquired. It must be held for the
1180  * duration of the iteration.
1181  *
1182  * Sets the given iterator.
1183  */
1184 void agent_find_events_by_name(const char *name, struct agent *agt,
1185                 struct lttng_ht_iter* iter)
1186 {
1187         struct lttng_ht *ht;
1188         struct agent_ht_key key;
1189
1190         assert(name);
1191         assert(agt);
1192         assert(agt->events);
1193         assert(iter);
1194
1195         ht = agt->events;
1196         key.name = name;
1197
1198         cds_lfht_lookup(ht->ht, ht->hash_fct((void *) name, lttng_ht_seed),
1199                         ht_match_event_by_name, &key, &iter->iter);
1200 }
1201
1202 /*
1203  * Get the next agent event duplicate by name. This should be called
1204  * after a call to agent_find_events_by_name() to iterate on events.
1205  *
1206  * The RCU read lock must be held during the iteration and for as long
1207  * as the object the iterator points to remains in use.
1208  */
1209 void agent_event_next_duplicate(const char *name,
1210                 struct agent *agt, struct lttng_ht_iter* iter)
1211 {
1212         struct agent_ht_key key;
1213
1214         key.name = name;
1215
1216         cds_lfht_next_duplicate(agt->events->ht, ht_match_event_by_name,
1217                 &key, &iter->iter);
1218 }
1219
1220 /*
1221  * Find a agent event in the given agent using name, loglevel and filter.
1222  *
1223  * RCU read side lock MUST be acquired. It must be kept for as long as
1224  * the returned agent_event is used.
1225  *
1226  * Return object if found else NULL.
1227  */
1228 struct agent_event *agent_find_event(const char *name,
1229                 enum lttng_loglevel_type loglevel_type, int loglevel_value,
1230                 char *filter_expression, struct agent *agt)
1231 {
1232         struct lttng_ht_node_str *node;
1233         struct lttng_ht_iter iter;
1234         struct lttng_ht *ht;
1235         struct agent_ht_key key;
1236
1237         assert(name);
1238         assert(agt);
1239         assert(agt->events);
1240
1241         ht = agt->events;
1242         key.name = name;
1243         key.loglevel_value = loglevel_value;
1244         key.loglevel_type = loglevel_type;
1245         key.filter_expression = filter_expression;
1246
1247         cds_lfht_lookup(ht->ht, ht->hash_fct((void *) name, lttng_ht_seed),
1248                         ht_match_event, &key, &iter.iter);
1249         node = lttng_ht_iter_get_node_str(&iter);
1250         if (node == NULL) {
1251                 goto error;
1252         }
1253
1254         DBG3("Agent event found %s.", name);
1255         return caa_container_of(node, struct agent_event, node);
1256
1257 error:
1258         DBG3("Agent event NOT found %s.", name);
1259         return NULL;
1260 }
1261
1262 /*
1263  * Free given agent event. This event must not be globally visible at this
1264  * point (only expected to be used on failure just after event creation). After
1265  * this call, the pointer is not usable anymore.
1266  */
1267 void agent_destroy_event(struct agent_event *event)
1268 {
1269         assert(event);
1270
1271         free(event->filter);
1272         free(event->filter_expression);
1273         free(event->exclusion);
1274         free(event);
1275 }
1276
1277 static
1278 void destroy_app_ctx_rcu(struct rcu_head *head)
1279 {
1280         struct agent_app_ctx *ctx =
1281                         caa_container_of(head, struct agent_app_ctx, rcu_node);
1282
1283         destroy_app_ctx(ctx);
1284 }
1285
1286 /*
1287  * Destroy an agent completely.
1288  */
1289 void agent_destroy(struct agent *agt)
1290 {
1291         struct lttng_ht_node_str *node;
1292         struct lttng_ht_iter iter;
1293         struct agent_app_ctx *ctx;
1294
1295         assert(agt);
1296
1297         DBG3("Agent destroy");
1298
1299         rcu_read_lock();
1300         cds_lfht_for_each_entry(agt->events->ht, &iter.iter, node, node) {
1301                 int ret;
1302                 struct agent_event *event;
1303
1304                 /*
1305                  * When destroying an event, we have to try to disable it on the
1306                  * agent side so the event stops generating data. The return
1307                  * value is not important since we have to continue anyway
1308                  * destroying the object.
1309                  */
1310                 event = caa_container_of(node, struct agent_event, node);
1311                 (void) agent_disable_event(event, agt->domain);
1312
1313                 ret = lttng_ht_del(agt->events, &iter);
1314                 assert(!ret);
1315                 call_rcu(&node->head, destroy_event_agent_rcu);
1316         }
1317
1318         cds_list_for_each_entry_rcu(ctx, &agt->app_ctx_list, list_node) {
1319                 (void) disable_context(ctx, agt->domain);
1320                 cds_list_del(&ctx->list_node);
1321                 call_rcu(&ctx->rcu_node, destroy_app_ctx_rcu);
1322         }
1323         rcu_read_unlock();
1324         ht_cleanup_push(agt->events);
1325         free(agt);
1326 }
1327
1328 /*
1329  * Allocate agent_apps_ht_by_sock.
1330  */
1331 int agent_app_ht_alloc(void)
1332 {
1333         int ret = 0;
1334
1335         agent_apps_ht_by_sock = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
1336         if (!agent_apps_ht_by_sock) {
1337                 ret = -1;
1338         }
1339
1340         return ret;
1341 }
1342
1343 /*
1344  * Destroy a agent application by socket.
1345  */
1346 void agent_destroy_app_by_sock(int sock)
1347 {
1348         struct agent_app *app;
1349
1350         assert(sock >= 0);
1351
1352         /*
1353          * Not finding an application is a very important error that should NEVER
1354          * happen. The hash table deletion is ONLY done through this call when the
1355          * main sessiond thread is torn down.
1356          */
1357         rcu_read_lock();
1358         app = agent_find_app_by_sock(sock);
1359         assert(app);
1360
1361         /* RCU read side lock is assumed to be held by this function. */
1362         agent_delete_app(app);
1363
1364         /* The application is freed in a RCU call but the socket is closed here. */
1365         agent_destroy_app(app);
1366         rcu_read_unlock();
1367 }
1368
1369 /*
1370  * Clean-up the agent app hash table and destroy it.
1371  */
1372 void agent_app_ht_clean(void)
1373 {
1374         struct lttng_ht_node_ulong *node;
1375         struct lttng_ht_iter iter;
1376
1377         if (!agent_apps_ht_by_sock) {
1378                 return;
1379         }
1380         rcu_read_lock();
1381         cds_lfht_for_each_entry(agent_apps_ht_by_sock->ht, &iter.iter, node, node) {
1382                 struct agent_app *app;
1383
1384                 app = caa_container_of(node, struct agent_app, node);
1385                 agent_destroy_app_by_sock(app->sock->fd);
1386         }
1387         rcu_read_unlock();
1388
1389         lttng_ht_destroy(agent_apps_ht_by_sock);
1390 }
1391
1392 /*
1393  * Update a agent application (given socket) using the given agent.
1394  *
1395  * Note that this function is most likely to be used with a tracing session
1396  * thus the caller should make sure to hold the appropriate lock(s).
1397  */
1398 void agent_update(struct agent *agt, int sock)
1399 {
1400         int ret;
1401         struct agent_app *app;
1402         struct agent_event *event;
1403         struct lttng_ht_iter iter;
1404         struct agent_app_ctx *ctx;
1405
1406         assert(agt);
1407         assert(sock >= 0);
1408
1409         DBG("Agent updating app socket %d", sock);
1410
1411         rcu_read_lock();
1412         app = agent_find_app_by_sock(sock);
1413         /*
1414          * We are in the registration path thus if the application is gone,
1415          * there is a serious code flow error.
1416          */
1417         assert(app);
1418         cds_lfht_for_each_entry(agt->events->ht, &iter.iter, event, node.node) {
1419                 /* Skip event if disabled. */
1420                 if (!event->enabled) {
1421                         continue;
1422                 }
1423
1424                 ret = enable_event(app, event);
1425                 if (ret != LTTNG_OK) {
1426                         DBG2("Agent update unable to enable event %s on app pid: %d sock %d",
1427                                         event->name, app->pid, app->sock->fd);
1428                         /* Let's try the others here and don't assume the app is dead. */
1429                         continue;
1430                 }
1431         }
1432
1433         cds_list_for_each_entry_rcu(ctx, &agt->app_ctx_list, list_node) {
1434                 ret = app_context_op(app, ctx, AGENT_CMD_APP_CTX_ENABLE);
1435                 if (ret != LTTNG_OK) {
1436                         DBG2("Agent update unable to add application context %s:%s on app pid: %d sock %d",
1437                                         ctx->provider_name, ctx->ctx_name,
1438                                         app->pid, app->sock->fd);
1439                         continue;
1440                 }
1441         }
1442
1443         rcu_read_unlock();
1444 }