src/bin/lttng-sessiond/save.c

   1 /*
   2  * Copyright (C) 2014 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License, version 2 only, as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program; if not, write to the Free Software Foundation, Inc., 51
  15  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #define _LGPL_SOURCE
  19 #include <assert.h>
  20 #include <inttypes.h>
  21 #include <string.h>
  22 #include <urcu/uatomic.h>
  23 #include <unistd.h>
  24
  25 #include <common/defaults.h>
  26 #include <common/error.h>
  27 #include <common/config/session-config.h>
  28 #include <common/utils.h>
  29 #include <common/runas.h>
  30 #include <lttng/save-internal.h>
  31
  32 #include "kernel.h"
  33 #include "save.h"
  34 #include "session.h"
  35 #include "lttng-syscall.h"
  36 #include "trace-ust.h"
  37 #include "agent.h"
  38
  39 static
  40 int save_kernel_channel_attributes(struct config_writer *writer,
  41         struct lttng_channel_attr *attr)
  42 {
  43         int ret;
  44
  45         ret = config_writer_write_element_string(writer,
  46                 config_element_overwrite_mode,
  47                 attr->overwrite ? config_overwrite_mode_overwrite :
  48                         config_overwrite_mode_discard);
  49         if (ret) {
  50                 goto end;
  51         }
  52
  53         ret = config_writer_write_element_unsigned_int(writer,
  54                 config_element_subbuf_size, attr->subbuf_size);
  55         if (ret) {
  56                 goto end;
  57         }
  58
  59         ret = config_writer_write_element_unsigned_int(writer,
  60                 config_element_num_subbuf,
  61                 attr->num_subbuf);
  62         if (ret) {
  63                 goto end;
  64         }
  65
  66         ret = config_writer_write_element_unsigned_int(writer,
  67                 config_element_switch_timer_interval,
  68                 attr->switch_timer_interval);
  69         if (ret) {
  70                 goto end;
  71         }
  72
  73         ret = config_writer_write_element_unsigned_int(writer,
  74                 config_element_read_timer_interval,
  75                 attr->read_timer_interval);
  76         if (ret) {
  77                 goto end;
  78         }
  79
  80         ret = config_writer_write_element_string(writer,
  81                 config_element_output_type,
  82                 attr->output == LTTNG_EVENT_SPLICE ?
  83                 config_output_type_splice : config_output_type_mmap);
  84         if (ret) {
  85                 goto end;
  86         }
  87
  88         ret = config_writer_write_element_unsigned_int(writer,
  89                 config_element_tracefile_size, attr->tracefile_size);
  90         if (ret) {
  91                 goto end;
  92         }
  93
  94         ret = config_writer_write_element_unsigned_int(writer,
  95                 config_element_tracefile_count,
  96                 attr->tracefile_count);
  97         if (ret) {
  98                 goto end;
  99         }
 100
 101         ret = config_writer_write_element_unsigned_int(writer,
 102                 config_element_live_timer_interval,
 103                 attr->live_timer_interval);
 104         if (ret) {
 105                 goto end;
 106         }
 107
 108         if (attr->extended.ptr) {
 109                 struct lttng_channel_extended *ext = NULL;
 110
 111                 ext = (struct lttng_channel_extended *) attr->extended.ptr;
 112                 ret = config_writer_write_element_unsigned_int(writer,
 113                                 config_element_monitor_timer_interval,
 114                                 ext->monitor_timer_interval);
 115                 if (ret) {
 116                         goto end;
 117                 }
 118
 119                 ret = config_writer_write_element_signed_int(writer,
 120                                 config_element_blocking_timeout,
 121                                 ext->blocking_timeout);
 122                 if (ret) {
 123                         goto end;
 124                 }
 125         }
 126
 127 end:
 128         return ret ? LTTNG_ERR_SAVE_IO_FAIL : 0;
 129 }
 130
 131 static
 132 int save_ust_channel_attributes(struct config_writer *writer,
 133         struct lttng_ust_channel_attr *attr)
 134 {
 135         int ret;
 136         struct ltt_ust_channel *channel = NULL;
 137
 138         ret = config_writer_write_element_string(writer,
 139                 config_element_overwrite_mode,
 140                 attr->overwrite ? config_overwrite_mode_overwrite :
 141                         config_overwrite_mode_discard);
 142         if (ret) {
 143                 goto end;
 144         }
 145
 146         ret = config_writer_write_element_unsigned_int(writer,
 147                 config_element_subbuf_size, attr->subbuf_size);
 148         if (ret) {
 149                 goto end;
 150         }
 151
 152         ret = config_writer_write_element_unsigned_int(writer,
 153                 config_element_num_subbuf,
 154                 attr->num_subbuf);
 155         if (ret) {
 156                 goto end;
 157         }
 158
 159         ret = config_writer_write_element_unsigned_int(writer,
 160                 config_element_switch_timer_interval,
 161                 attr->switch_timer_interval);
 162         if (ret) {
 163                 goto end;
 164         }
 165
 166         ret = config_writer_write_element_unsigned_int(writer,
 167                 config_element_read_timer_interval,
 168                 attr->read_timer_interval);
 169         if (ret) {
 170                 goto end;
 171         }
 172
 173         ret = config_writer_write_element_string(writer,
 174                 config_element_output_type,
 175                 attr->output == LTTNG_UST_MMAP ?
 176                 config_output_type_mmap : config_output_type_splice);
 177         if (ret) {
 178                 goto end;
 179         }
 180
 181         ret = config_writer_write_element_signed_int(writer,
 182                         config_element_blocking_timeout,
 183                         attr->u.s.blocking_timeout);
 184         if (ret) {
 185                 goto end;
 186         }
 187
 188         /*
 189          * Fetch the monitor timer which is located in the parent of
 190          * lttng_ust_channel_attr
 191          */
 192         channel = caa_container_of(attr, struct ltt_ust_channel, attr);
 193         ret = config_writer_write_element_unsigned_int(writer,
 194                 config_element_monitor_timer_interval,
 195                 channel->monitor_timer_interval);
 196         if (ret) {
 197                 goto end;
 198         }
 199
 200 end:
 201         return ret ? LTTNG_ERR_SAVE_IO_FAIL : 0;
 202 }
 203
 204 static
 205 const char *get_kernel_instrumentation_string(
 206         enum lttng_kernel_instrumentation instrumentation)
 207 {
 208         const char *instrumentation_string;
 209
 210         switch (instrumentation) {
 211         case LTTNG_KERNEL_ALL:
 212                 instrumentation_string = config_event_type_all;
 213                 break;
 214         case LTTNG_KERNEL_TRACEPOINT:
 215                 instrumentation_string = config_event_type_tracepoint;
 216                 break;
 217         case LTTNG_KERNEL_KPROBE:
 218                 instrumentation_string = config_event_type_kprobe;
 219                 break;
 220         case LTTNG_KERNEL_FUNCTION:
 221                 instrumentation_string = config_event_type_function;
 222                 break;
 223         case LTTNG_KERNEL_KRETPROBE:
 224                 instrumentation_string = config_event_type_kretprobe;
 225                 break;
 226         case LTTNG_KERNEL_NOOP:
 227                 instrumentation_string = config_event_type_noop;
 228                 break;
 229         case LTTNG_KERNEL_SYSCALL:
 230                 instrumentation_string = config_event_type_syscall;
 231                 break;
 232         default:
 233                 instrumentation_string = NULL;
 234         }
 235
 236         return instrumentation_string;
 237 }
 238
 239 static
 240 const char *get_kernel_context_type_string(
 241         enum lttng_kernel_context_type context_type)
 242 {
 243         const char *context_type_string;
 244
 245         switch (context_type) {
 246         case LTTNG_KERNEL_CONTEXT_PID:
 247                 context_type_string = config_event_context_pid;
 248                 break;
 249         case LTTNG_KERNEL_CONTEXT_PROCNAME:
 250                 context_type_string = config_event_context_procname;
 251                 break;
 252         case LTTNG_KERNEL_CONTEXT_PRIO:
 253                 context_type_string = config_event_context_prio;
 254                 break;
 255         case LTTNG_KERNEL_CONTEXT_NICE:
 256                 context_type_string = config_event_context_nice;
 257                 break;
 258         case LTTNG_KERNEL_CONTEXT_VPID:
 259                 context_type_string = config_event_context_vpid;
 260                 break;
 261         case LTTNG_KERNEL_CONTEXT_TID:
 262                 context_type_string = config_event_context_tid;
 263                 break;
 264         case LTTNG_KERNEL_CONTEXT_VTID:
 265                 context_type_string = config_event_context_vtid;
 266                 break;
 267         case LTTNG_KERNEL_CONTEXT_PPID:
 268                 context_type_string = config_event_context_ppid;
 269                 break;
 270         case LTTNG_KERNEL_CONTEXT_VPPID:
 271                 context_type_string = config_event_context_vppid;
 272                 break;
 273         case LTTNG_KERNEL_CONTEXT_HOSTNAME:
 274                 context_type_string = config_event_context_hostname;
 275                 break;
 276         case LTTNG_KERNEL_CONTEXT_INTERRUPTIBLE:
 277                 context_type_string = config_event_context_interruptible;
 278                 break;
 279         case LTTNG_KERNEL_CONTEXT_PREEMPTIBLE:
 280                 context_type_string = config_event_context_preemptible;
 281                 break;
 282         case LTTNG_KERNEL_CONTEXT_NEED_RESCHEDULE:
 283                 context_type_string = config_event_context_need_reschedule;
 284                 break;
 285         case LTTNG_KERNEL_CONTEXT_MIGRATABLE:
 286                 context_type_string = config_event_context_migratable;
 287                 break;
 288         case LTTNG_KERNEL_CONTEXT_CALLSTACK_USER:
 289                 context_type_string = config_event_context_callstack_user;
 290                 break;
 291         case LTTNG_KERNEL_CONTEXT_CALLSTACK_KERNEL:
 292                 context_type_string = config_event_context_callstack_kernel;
 293                 break;
 294         default:
 295                 context_type_string = NULL;
 296         }
 297
 298         return context_type_string;
 299 }
 300
 301 static
 302 const char *get_ust_context_type_string(
 303         enum lttng_ust_context_type context_type)
 304 {
 305         const char *context_type_string;
 306
 307         switch (context_type) {
 308         case LTTNG_UST_CONTEXT_PROCNAME:
 309                 context_type_string = config_event_context_procname;
 310                 break;
 311         case LTTNG_UST_CONTEXT_VPID:
 312                 context_type_string = config_event_context_vpid;
 313                 break;
 314         case LTTNG_UST_CONTEXT_VTID:
 315                 context_type_string = config_event_context_vtid;
 316                 break;
 317         case LTTNG_UST_CONTEXT_IP:
 318                 context_type_string = config_event_context_ip;
 319                 break;
 320         case LTTNG_UST_CONTEXT_PTHREAD_ID:
 321                 context_type_string = config_event_context_pthread_id;
 322                 break;
 323         case LTTNG_UST_CONTEXT_APP_CONTEXT:
 324                 context_type_string = config_event_context_app;
 325                 break;
 326         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
 327                 /*
 328                  * Error, should not be stored in the XML, perf contexts
 329                  * are stored as a node of type event_perf_context_type.
 330                  */
 331         default:
 332                 context_type_string = NULL;
 333                 break;
 334         }
 335
 336         return context_type_string;
 337 }
 338
 339 static
 340 const char *get_buffer_type_string(
 341         enum lttng_buffer_type buffer_type)
 342 {
 343         const char *buffer_type_string;
 344
 345         switch (buffer_type) {
 346         case LTTNG_BUFFER_PER_PID:
 347                 buffer_type_string = config_buffer_type_per_pid;
 348                 break;
 349         case LTTNG_BUFFER_PER_UID:
 350                 buffer_type_string = config_buffer_type_per_uid;
 351                 break;
 352         case LTTNG_BUFFER_GLOBAL:
 353                 buffer_type_string = config_buffer_type_global;
 354                 break;
 355         default:
 356                 buffer_type_string = NULL;
 357         }
 358
 359         return buffer_type_string;
 360 }
 361
 362 static
 363 const char *get_loglevel_type_string(
 364         enum lttng_ust_loglevel_type loglevel_type)
 365 {
 366         const char *loglevel_type_string;
 367
 368         switch (loglevel_type) {
 369         case LTTNG_UST_LOGLEVEL_ALL:
 370                 loglevel_type_string = config_loglevel_type_all;
 371                 break;
 372         case LTTNG_UST_LOGLEVEL_RANGE:
 373                 loglevel_type_string = config_loglevel_type_range;
 374                 break;
 375         case LTTNG_UST_LOGLEVEL_SINGLE:
 376                 loglevel_type_string = config_loglevel_type_single;
 377                 break;
 378         default:
 379                 loglevel_type_string = NULL;
 380         }
 381
 382         return loglevel_type_string;
 383 }
 384
 385 static
 386 int save_kernel_event(struct config_writer *writer,
 387         struct ltt_kernel_event *event)
 388 {
 389         int ret;
 390         const char *instrumentation_type;
 391
 392         ret = config_writer_open_element(writer, config_element_event);
 393         if (ret) {
 394                 ret = LTTNG_ERR_SAVE_IO_FAIL;
 395                 goto end;
 396         }
 397
 398         if (event->event->name[0]) {
 399                 ret = config_writer_write_element_string(writer,
 400                         config_element_name, event->event->name);
 401                 if (ret) {
 402                         ret = LTTNG_ERR_SAVE_IO_FAIL;
 403                         goto end;
 404                 }
 405         }
 406
 407         ret = config_writer_write_element_bool(writer, config_element_enabled,
 408                 event->enabled);
 409         if (ret) {
 410                 ret = LTTNG_ERR_SAVE_IO_FAIL;
 411                 goto end;
 412         }
 413
 414         instrumentation_type = get_kernel_instrumentation_string(
 415                 event->event->instrumentation);
 416         if (!instrumentation_type) {
 417                 ret = LTTNG_ERR_INVALID;
 418                 goto end;
 419         }
 420
 421         ret = config_writer_write_element_string(writer, config_element_type,
 422                 instrumentation_type);
 423         if (ret) {
 424                 ret = LTTNG_ERR_SAVE_IO_FAIL;
 425                 goto end;
 426         }
 427
 428         if (event->filter_expression) {
 429                 ret = config_writer_write_element_string(writer,
 430                                 config_element_filter,
 431                                 event->filter_expression);
 432                 if (ret) {
 433                         ret = LTTNG_ERR_SAVE_IO_FAIL;
 434                         goto end;
 435                 }
 436         }
 437
 438         if (event->event->instrumentation == LTTNG_KERNEL_FUNCTION ||
 439                 event->event->instrumentation == LTTNG_KERNEL_KPROBE ||
 440                 event->event->instrumentation == LTTNG_KERNEL_KRETPROBE) {
 441
 442                 ret = config_writer_open_element(writer,
 443                         config_element_attributes);
 444                 if (ret) {
 445                         ret = LTTNG_ERR_SAVE_IO_FAIL;
 446                         goto end;
 447                 }
 448
 449                 switch (event->event->instrumentation) {
 450                 case LTTNG_KERNEL_SYSCALL:
 451                 case LTTNG_KERNEL_FUNCTION:
 452                         ret = config_writer_open_element(writer,
 453                                 config_element_function_attributes);
 454                         if (ret) {
 455                                 ret = LTTNG_ERR_SAVE_IO_FAIL;
 456                                 goto end;
 457                         }
 458
 459                         ret = config_writer_write_element_string(writer,
 460                                 config_element_name,
 461                                 event->event->u.ftrace.symbol_name);
 462                         if (ret) {
 463                                 ret = LTTNG_ERR_SAVE_IO_FAIL;
 464                                 goto end;
 465                         }
 466
 467                         /* /function attributes */
 468                         ret = config_writer_close_element(writer);
 469                         if (ret) {
 470                                 ret = LTTNG_ERR_SAVE_IO_FAIL;
 471                                 goto end;
 472                         }
 473                         break;
 474                 case LTTNG_KERNEL_KPROBE:
 475                 case LTTNG_KERNEL_KRETPROBE:
 476                 {
 477                         const char *symbol_name;
 478                         uint64_t addr;
 479                         uint64_t offset;
 480
 481                         if (event->event->instrumentation ==
 482                                 LTTNG_KERNEL_KPROBE) {
 483                                 /*
 484                                  * Comments in lttng-kernel.h mention that
 485                                  * either addr or symbol_name are set, not both.
 486                                  */
 487                                 addr = event->event->u.kprobe.addr;
 488                                 offset = event->event->u.kprobe.offset;
 489                                 symbol_name = addr ? NULL :
 490                                         event->event->u.kprobe.symbol_name;
 491                         } else {
 492                                 symbol_name =
 493                                         event->event->u.kretprobe.symbol_name;
 494                                 addr = event->event->u.kretprobe.addr;
 495                                 offset = event->event->u.kretprobe.offset;
 496                         }
 497
 498                         ret = config_writer_open_element(writer,
 499                                 config_element_probe_attributes);
 500                         if (ret) {
 501                                 ret = LTTNG_ERR_SAVE_IO_FAIL;
 502                                 goto end;
 503                         }
 504
 505                         if (symbol_name) {
 506                                 ret = config_writer_write_element_string(writer,
 507                                         config_element_symbol_name,
 508                                         symbol_name);
 509                                 if (ret) {
 510                                         ret = LTTNG_ERR_SAVE_IO_FAIL;
 511                                         goto end;
 512                                 }
 513                         }
 514
 515                         if (addr) {
 516                                 ret = config_writer_write_element_unsigned_int(
 517                                         writer, config_element_address, addr);
 518                                 if (ret) {
 519                                         ret = LTTNG_ERR_SAVE_IO_FAIL;
 520                                         goto end;
 521                                 }
 522                         }
 523
 524                         if (offset) {
 525                                 ret = config_writer_write_element_unsigned_int(
 526                                         writer, config_element_offset, offset);
 527                                 if (ret) {
 528                                         ret = LTTNG_ERR_SAVE_IO_FAIL;
 529                                         goto end;
 530                                 }
 531                         }
 532
 533                         ret = config_writer_close_element(writer);
 534                         if (ret) {
 535                                 ret = LTTNG_ERR_SAVE_IO_FAIL;
 536                                 goto end;
 537                         }
 538                         break;
 539                 }
 540                 default:
 541                         ERR("Unsupported kernel instrumentation type.");
 542                         ret = LTTNG_ERR_INVALID;
 543                         goto end;
 544                 }
 545
 546                 /* /attributes */
 547                 ret = config_writer_close_element(writer);
 548                 if (ret) {
 549                         ret = LTTNG_ERR_SAVE_IO_FAIL;
 550                         goto end;
 551                 }
 552         }
 553
 554         /* /event */
 555         ret = config_writer_close_element(writer);
 556         if (ret) {
 557                 ret = LTTNG_ERR_SAVE_IO_FAIL;
 558                 goto end;
 559         }
 560 end:
 561         return ret;
 562 }
 563
 564 static
 565 int save_kernel_events(struct config_writer *writer,
 566         struct ltt_kernel_channel *kchan)
 567 {
 568         int ret;
 569         struct ltt_kernel_event *event;
 570
 571         ret = config_writer_open_element(writer, config_element_events);
 572         if (ret) {
 573                 ret = LTTNG_ERR_SAVE_IO_FAIL;
 574                 goto end;
 575         }
 576
 577         cds_list_for_each_entry(event, &kchan->events_list.head, list) {
 578                 ret = save_kernel_event(writer, event);
 579                 if (ret) {
 580                         goto end;
 581                 }
 582         }
 583
 584         /* /events */
 585         ret = config_writer_close_element(writer);
 586         if (ret) {
 587                 ret = LTTNG_ERR_SAVE_IO_FAIL;
 588                 goto end;
 589         }
 590 end:
 591         return ret;
 592 }
 593
 594 static
 595 int save_ust_event(struct config_writer *writer,
 596         struct ltt_ust_event *event)
 597 {
 598         int ret;
 599         const char *loglevel_type_string;
 600
 601         ret = config_writer_open_element(writer, config_element_event);
 602         if (ret) {
 603                 ret = LTTNG_ERR_SAVE_IO_FAIL;
 604                 goto end;
 605         }
 606
 607         if (event->attr.name[0]) {
 608                 ret = config_writer_write_element_string(writer,
 609                         config_element_name, event->attr.name);
 610                 if (ret) {
 611                         ret = LTTNG_ERR_SAVE_IO_FAIL;
 612                         goto end;
 613                 }
 614         }
 615
 616         ret = config_writer_write_element_bool(writer, config_element_enabled,
 617                 event->enabled);
 618         if (ret) {
 619                 ret = LTTNG_ERR_SAVE_IO_FAIL;
 620                 goto end;
 621         }
 622
 623         if (event->attr.instrumentation != LTTNG_UST_TRACEPOINT) {
 624                 ERR("Unsupported UST instrumentation type.");
 625                 ret = LTTNG_ERR_INVALID;
 626                 goto end;
 627         }
 628         ret = config_writer_write_element_string(writer, config_element_type,
 629                 config_event_type_tracepoint);
 630         if (ret) {
 631                 ret = LTTNG_ERR_SAVE_IO_FAIL;
 632                 goto end;
 633         }
 634
 635         loglevel_type_string = get_loglevel_type_string(
 636                 event->attr.loglevel_type);
 637         if (!loglevel_type_string) {
 638                 ERR("Unsupported UST loglevel type.");
 639                 ret = LTTNG_ERR_INVALID;
 640                 goto end;
 641         }
 642
 643         ret = config_writer_write_element_string(writer,
 644                 config_element_loglevel_type, loglevel_type_string);
 645         if (ret) {
 646                 ret = LTTNG_ERR_SAVE_IO_FAIL;
 647                 goto end;
 648         }
 649
 650         /* The log level is irrelevant if no "filtering" is enabled */
 651         if (event->attr.loglevel_type != LTTNG_UST_LOGLEVEL_ALL) {
 652                 ret = config_writer_write_element_signed_int(writer,
 653                                 config_element_loglevel, event->attr.loglevel);
 654                 if (ret) {
 655                         ret = LTTNG_ERR_SAVE_IO_FAIL;
 656                         goto end;
 657                 }
 658         }
 659
 660         if (event->filter_expression) {
 661                 ret = config_writer_write_element_string(writer,
 662                         config_element_filter, event->filter_expression);
 663                 if (ret) {
 664                         ret = LTTNG_ERR_SAVE_IO_FAIL;
 665                         goto end;
 666                 }
 667         }
 668
 669         if (event->exclusion && event->exclusion->count) {
 670                 uint32_t i;
 671
 672                 ret = config_writer_open_element(writer,
 673                         config_element_exclusions);
 674                 if (ret) {
 675                         ret = LTTNG_ERR_SAVE_IO_FAIL;
 676                         goto end;
 677                 }
 678
 679                 for (i = 0; i < event->exclusion->count; i++) {
 680                         ret = config_writer_write_element_string(writer,
 681                                 config_element_exclusion,
 682                                 LTTNG_EVENT_EXCLUSION_NAME_AT(
 683                                         event->exclusion, i));
 684                         if (ret) {
 685                                 ret = LTTNG_ERR_SAVE_IO_FAIL;
 686                                 goto end;
 687                         }
 688                 }
 689
 690                 /* /exclusions */
 691                 ret = config_writer_close_element(writer);
 692                 if (ret) {
 693                         ret = LTTNG_ERR_SAVE_IO_FAIL;
 694                         goto end;
 695                 }
 696         }
 697
 698         /* /event */
 699         ret = config_writer_close_element(writer);
 700         if (ret) {
 701                 ret = LTTNG_ERR_SAVE_IO_FAIL;
 702                 goto end;
 703         }
 704 end:
 705         return ret;
 706 }
 707
 708 static
 709 int save_ust_events(struct config_writer *writer,
 710         struct lttng_ht *events)
 711 {
 712         int ret;
 713         struct ltt_ust_event *event;
 714         struct lttng_ht_node_str *node;
 715         struct lttng_ht_iter iter;
 716
 717         ret = config_writer_open_element(writer, config_element_events);
 718         if (ret) {
 719                 ret = LTTNG_ERR_SAVE_IO_FAIL;
 720                 goto end;
 721         }
 722
 723         rcu_read_lock();
 724         cds_lfht_for_each_entry(events->ht, &iter.iter, node, node) {
 725                 event = caa_container_of(node, struct ltt_ust_event, node);
 726
 727                 if (event->internal) {
 728                         /* Internal events must not be exposed to clients */
 729                         continue;
 730                 }
 731                 ret = save_ust_event(writer, event);
 732                 if (ret) {
 733                         rcu_read_unlock();
 734                         goto end;
 735                 }
 736         }
 737         rcu_read_unlock();
 738
 739         /* /events */
 740         ret = config_writer_close_element(writer);
 741         if (ret) {
 742                 ret = LTTNG_ERR_SAVE_IO_FAIL;
 743                 goto end;
 744         }
 745 end:
 746         return ret;
 747 }
 748
 749 static
 750 int init_ust_event_from_agent_event(struct ltt_ust_event *ust_event,
 751                 struct agent_event *agent_event)
 752 {
 753         int ret = 0;
 754         enum lttng_ust_loglevel_type ust_loglevel_type;
 755
 756         ust_event->enabled = agent_event->enabled;
 757         ust_event->attr.instrumentation = LTTNG_UST_TRACEPOINT;
 758         if (lttng_strncpy(ust_event->attr.name, agent_event->name,
 759                         LTTNG_SYMBOL_NAME_LEN)) {
 760                 ret = -1;
 761                 goto end;
 762         }
 763         switch (agent_event->loglevel_type) {
 764         case LTTNG_EVENT_LOGLEVEL_ALL:
 765                 ust_loglevel_type = LTTNG_UST_LOGLEVEL_ALL;
 766                 break;
 767         case LTTNG_EVENT_LOGLEVEL_SINGLE:
 768                 ust_loglevel_type = LTTNG_UST_LOGLEVEL_SINGLE;
 769                 break;
 770         case LTTNG_EVENT_LOGLEVEL_RANGE:
 771                 ust_loglevel_type = LTTNG_UST_LOGLEVEL_RANGE;
 772                 break;
 773         default:
 774                 ERR("Invalid agent_event loglevel_type.");
 775                 ret = -1;
 776                 goto end;
 777         }
 778
 779         ust_event->attr.loglevel_type = ust_loglevel_type;
 780         ust_event->attr.loglevel = agent_event->loglevel_value;
 781         ust_event->filter_expression = agent_event->filter_expression;
 782         ust_event->exclusion = agent_event->exclusion;
 783 end:
 784         return ret;
 785 }
 786
 787 static
 788 int save_agent_events(struct config_writer *writer,
 789                 struct agent *agent)
 790 {
 791         int ret;
 792         struct lttng_ht_iter iter;
 793         struct lttng_ht_node_str *node;
 794
 795         ret = config_writer_open_element(writer, config_element_events);
 796         if (ret) {
 797                 ret = LTTNG_ERR_SAVE_IO_FAIL;
 798                 goto end;
 799         }
 800
 801         rcu_read_lock();
 802         cds_lfht_for_each_entry(agent->events->ht, &iter.iter, node, node) {
 803                 int ret;
 804                 struct agent_event *agent_event;
 805                 struct ltt_ust_event fake_event;
 806
 807                 memset(&fake_event, 0, sizeof(fake_event));
 808                 agent_event = caa_container_of(node, struct agent_event, node);
 809
 810                 /*
 811                  * Initialize a fake ust event to reuse the same serialization
 812                  * function since UST and agent events contain the same info
 813                  * (and one could wonder why they don't reuse the same
 814                  * structures...).
 815                  */
 816                 ret = init_ust_event_from_agent_event(&fake_event, agent_event);
 817                 if (ret) {
 818                         rcu_read_unlock();
 819                         goto end;
 820                 }
 821                 ret = save_ust_event(writer, &fake_event);
 822                 if (ret) {
 823                         rcu_read_unlock();
 824                         goto end;
 825                 }
 826         }
 827         rcu_read_unlock();
 828
 829         /* /events */
 830         ret = config_writer_close_element(writer);
 831         if (ret) {
 832                 ret = LTTNG_ERR_SAVE_IO_FAIL;
 833                 goto end;
 834         }
 835 end:
 836         return ret;
 837 }
 838
 839 static
 840 int save_kernel_context(struct config_writer *writer,
 841         struct lttng_kernel_context *ctx)
 842 {
 843         int ret = 0;
 844
 845         if (!ctx) {
 846                 goto end;
 847         }
 848
 849         ret = config_writer_open_element(writer, config_element_context);
 850         if (ret) {
 851                 ret = LTTNG_ERR_SAVE_IO_FAIL;
 852                 goto end;
 853         }
 854
 855         if (ctx->ctx == LTTNG_KERNEL_CONTEXT_PERF_CPU_COUNTER) {
 856                 ret = config_writer_open_element(writer,
 857                                 config_element_context_perf);
 858                 if (ret) {
 859                         ret = LTTNG_ERR_SAVE_IO_FAIL;
 860                         goto end;
 861                 }
 862
 863                 ret = config_writer_write_element_unsigned_int(writer,
 864                         config_element_type, ctx->u.perf_counter.type);
 865                 if (ret) {
 866                         ret = LTTNG_ERR_SAVE_IO_FAIL;
 867                         goto end;
 868                 }
 869
 870                 ret = config_writer_write_element_unsigned_int(writer,
 871                         config_element_config, ctx->u.perf_counter.config);
 872                 if (ret) {
 873                         ret = LTTNG_ERR_SAVE_IO_FAIL;
 874                         goto end;
 875                 }
 876
 877                 ret = config_writer_write_element_string(writer,
 878                         config_element_name, ctx->u.perf_counter.name);
 879                 if (ret) {
 880                         ret = LTTNG_ERR_SAVE_IO_FAIL;
 881                         goto end;
 882                 }
 883
 884                 /* /perf */
 885                 ret = config_writer_close_element(writer);
 886                 if (ret) {
 887                         ret = LTTNG_ERR_SAVE_IO_FAIL;
 888                         goto end;
 889                 }
 890         } else {
 891                 const char *context_type_string =
 892                         get_kernel_context_type_string(ctx->ctx);
 893
 894                 if (!context_type_string) {
 895                         ERR("Unsupported kernel context type.");
 896                         ret = LTTNG_ERR_INVALID;
 897                         goto end;
 898                 }
 899
 900                 ret = config_writer_write_element_string(writer,
 901                         config_element_type, context_type_string);
 902                 if (ret) {
 903                         ret = LTTNG_ERR_SAVE_IO_FAIL;
 904                         goto end;
 905                 }
 906         }
 907
 908         /* /context */
 909         ret = config_writer_close_element(writer);
 910         if (ret) {
 911                 ret = LTTNG_ERR_SAVE_IO_FAIL;
 912                 goto end;
 913         }
 914
 915 end:
 916         return ret;
 917 }
 918
 919 static
 920 int save_kernel_contexts(struct config_writer *writer,
 921                 struct ltt_kernel_channel *kchan)
 922 {
 923         int ret;
 924         struct ltt_kernel_context *ctx;
 925
 926         if (cds_list_empty(&kchan->ctx_list)) {
 927                 ret = 0;
 928                 goto end;
 929         }
 930
 931         ret = config_writer_open_element(writer, config_element_contexts);
 932         if (ret) {
 933                 ret = LTTNG_ERR_SAVE_IO_FAIL;
 934                 goto end;
 935         }
 936
 937         cds_list_for_each_entry(ctx, &kchan->ctx_list, list) {
 938                 ret = save_kernel_context(writer, &ctx->ctx);
 939                 if (ret) {
 940                         goto end;
 941                 }
 942         }
 943
 944         /* /contexts */
 945         ret = config_writer_close_element(writer);
 946         if (ret) {
 947                 ret = LTTNG_ERR_SAVE_IO_FAIL;
 948                 goto end;
 949         }
 950 end:
 951         return ret;
 952 }
 953
 954 static
 955 int save_ust_context_perf_thread_counter(struct config_writer *writer,
 956                 struct ltt_ust_context *ctx)
 957 {
 958         int ret;
 959
 960         assert(writer);
 961         assert(ctx);
 962
 963         /* Perf contexts are saved as event_perf_context_type */
 964         ret = config_writer_open_element(writer, config_element_context_perf);
 965         if (ret) {
 966                 ret = LTTNG_ERR_SAVE_IO_FAIL;
 967                 goto end;
 968         }
 969
 970         ret = config_writer_write_element_unsigned_int(writer,
 971                         config_element_type, ctx->ctx.u.perf_counter.type);
 972         if (ret) {
 973                 ret = LTTNG_ERR_SAVE_IO_FAIL;
 974                 goto end;
 975         }
 976
 977         ret = config_writer_write_element_unsigned_int(writer,
 978                         config_element_config, ctx->ctx.u.perf_counter.config);
 979         if (ret) {
 980                 ret = LTTNG_ERR_SAVE_IO_FAIL;
 981                 goto end;
 982         }
 983
 984         ret = config_writer_write_element_string(writer, config_element_name,
 985                         ctx->ctx.u.perf_counter.name);
 986         if (ret) {
 987                 ret = LTTNG_ERR_SAVE_IO_FAIL;
 988                 goto end;
 989         }
 990
 991         /* /perf */
 992         ret = config_writer_close_element(writer);
 993         if (ret) {
 994                 ret = LTTNG_ERR_SAVE_IO_FAIL;
 995                 goto end;
 996         }
 997 end:
 998         return ret;
 999 }
1000
1001 static
1002 int save_ust_context_app_ctx(struct config_writer *writer,
1003                 struct ltt_ust_context *ctx)
1004 {
1005         int ret;
1006
1007         assert(writer);
1008         assert(ctx);
1009
1010         /* Application contexts are saved as application_context_type */
1011         ret = config_writer_open_element(writer, config_element_context_app);
1012         if (ret) {
1013                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1014                 goto end;
1015         }
1016
1017         ret = config_writer_write_element_string(writer,
1018                         config_element_context_app_provider_name,
1019                         ctx->ctx.u.app_ctx.provider_name);
1020         if (ret) {
1021                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1022                 goto end;
1023         }
1024
1025         ret = config_writer_write_element_string(writer,
1026                         config_element_context_app_ctx_name,
1027                         ctx->ctx.u.app_ctx.ctx_name);
1028         if (ret) {
1029                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1030                 goto end;
1031         }
1032
1033         /* /app */
1034         ret = config_writer_close_element(writer);
1035         if (ret) {
1036                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1037                 goto end;
1038         }
1039 end:
1040         return ret;
1041 }
1042
1043 static
1044 int save_ust_context_generic(struct config_writer *writer,
1045                 struct ltt_ust_context *ctx)
1046 {
1047         int ret;
1048         const char *context_type_string;
1049
1050         assert(writer);
1051         assert(ctx);
1052
1053         /* Save context as event_context_type_type */
1054         context_type_string = get_ust_context_type_string(
1055                         ctx->ctx.ctx);
1056         if (!context_type_string) {
1057                 ERR("Unsupported UST context type.");
1058                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1059                 goto end;
1060         }
1061
1062         ret = config_writer_write_element_string(writer,
1063                         config_element_type, context_type_string);
1064         if (ret) {
1065                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1066                 goto end;
1067         }
1068 end:
1069         return ret;
1070 }
1071
1072 static
1073 int save_ust_context(struct config_writer *writer,
1074         struct cds_list_head *ctx_list)
1075 {
1076         int ret;
1077         struct ltt_ust_context *ctx;
1078
1079         assert(writer);
1080         assert(ctx_list);
1081
1082         ret = config_writer_open_element(writer, config_element_contexts);
1083         if (ret) {
1084                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1085                 goto end;
1086         }
1087
1088         cds_list_for_each_entry(ctx, ctx_list, list) {
1089                 ret = config_writer_open_element(writer,
1090                         config_element_context);
1091                 if (ret) {
1092                         ret = LTTNG_ERR_SAVE_IO_FAIL;
1093                         goto end;
1094                 }
1095
1096                 switch (ctx->ctx.ctx) {
1097                 case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
1098                         ret = save_ust_context_perf_thread_counter(writer, ctx);
1099                         break;
1100                 case LTTNG_UST_CONTEXT_APP_CONTEXT:
1101                         ret = save_ust_context_app_ctx(writer, ctx);
1102                         break;
1103                 default:
1104                         /* Save generic context. */
1105                         ret = save_ust_context_generic(writer, ctx);
1106                 }
1107                 if (ret) {
1108                         goto end;
1109                 }
1110
1111                 /* /context */
1112                 ret = config_writer_close_element(writer);
1113                 if (ret) {
1114                         ret = LTTNG_ERR_SAVE_IO_FAIL;
1115                         goto end;
1116                 }
1117         }
1118
1119         /* /contexts */
1120         ret = config_writer_close_element(writer);
1121         if (ret) {
1122                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1123                 goto end;
1124         }
1125 end:
1126         return ret;
1127 }
1128
1129 static
1130 int save_kernel_channel(struct config_writer *writer,
1131         struct ltt_kernel_channel *kchan)
1132 {
1133         int ret;
1134
1135         assert(writer);
1136         assert(kchan);
1137
1138         ret = config_writer_open_element(writer, config_element_channel);
1139         if (ret) {
1140                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1141                 goto end;
1142         }
1143
1144         ret = config_writer_write_element_string(writer, config_element_name,
1145                 kchan->channel->name);
1146         if (ret) {
1147                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1148                 goto end;
1149         }
1150
1151         ret = config_writer_write_element_bool(writer, config_element_enabled,
1152                 kchan->channel->enabled);
1153         if (ret) {
1154                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1155                 goto end;
1156         }
1157
1158         ret = save_kernel_channel_attributes(writer, &kchan->channel->attr);
1159         if (ret) {
1160                 goto end;
1161         }
1162
1163         ret = save_kernel_events(writer, kchan);
1164         if (ret) {
1165                 goto end;
1166         }
1167
1168         ret = save_kernel_contexts(writer, kchan);
1169         if (ret) {
1170                 goto end;
1171         }
1172
1173         /* /channel */
1174         ret = config_writer_close_element(writer);
1175         if (ret) {
1176                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1177                 goto end;
1178         }
1179 end:
1180         return ret;
1181 }
1182
1183 static
1184 int save_ust_channel(struct config_writer *writer,
1185         struct ltt_ust_channel *ust_chan,
1186         struct ltt_ust_session *session)
1187 {
1188         int ret;
1189
1190         assert(writer);
1191         assert(ust_chan);
1192         assert(session);
1193
1194         ret = config_writer_open_element(writer, config_element_channel);
1195         if (ret) {
1196                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1197                 goto end;
1198         }
1199
1200         ret = config_writer_write_element_string(writer, config_element_name,
1201                 ust_chan->name);
1202         if (ret) {
1203                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1204                 goto end;
1205         }
1206
1207         ret = config_writer_write_element_bool(writer, config_element_enabled,
1208                 ust_chan->enabled);
1209         if (ret) {
1210                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1211                 goto end;
1212         }
1213
1214         ret = save_ust_channel_attributes(writer, &ust_chan->attr);
1215         if (ret) {
1216                 goto end;
1217         }
1218
1219         ret = config_writer_write_element_unsigned_int(writer,
1220                 config_element_tracefile_size, ust_chan->tracefile_size);
1221         if (ret) {
1222                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1223                 goto end;
1224         }
1225
1226         ret = config_writer_write_element_unsigned_int(writer,
1227                 config_element_tracefile_count, ust_chan->tracefile_count);
1228         if (ret) {
1229                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1230                 goto end;
1231         }
1232
1233         ret = config_writer_write_element_unsigned_int(writer,
1234                 config_element_live_timer_interval,
1235                 session->live_timer_interval);
1236         if (ret) {
1237                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1238                 goto end;
1239         }
1240
1241         if (ust_chan->domain == LTTNG_DOMAIN_UST) {
1242                 ret = save_ust_events(writer, ust_chan->events);
1243                 if (ret) {
1244                         goto end;
1245                 }
1246         } else {
1247                 struct agent *agent = NULL;
1248
1249                 agent = trace_ust_find_agent(session, ust_chan->domain);
1250                 if (!agent) {
1251                         ret = LTTNG_ERR_SAVE_IO_FAIL;
1252                         ERR("Could not find agent associated to UST subdomain");
1253                         goto end;
1254                 }
1255
1256                 /*
1257                  * Channels associated with a UST sub-domain (such as JUL, Log4j
1258                  * or Python) don't have any non-internal events. We retrieve
1259                  * the "agent" events associated with this channel and serialize
1260                  * them.
1261                  */
1262                 ret = save_agent_events(writer, agent);
1263                 if (ret) {
1264                         goto end;
1265                 }
1266         }
1267
1268         ret = save_ust_context(writer, &ust_chan->ctx_list);
1269         if (ret) {
1270                 goto end;
1271         }
1272
1273         /* /channel */
1274         ret = config_writer_close_element(writer);
1275         if (ret) {
1276                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1277                 goto end;
1278         }
1279 end:
1280         return ret;
1281 }
1282
1283 static
1284 int save_kernel_session(struct config_writer *writer,
1285         struct ltt_session *session)
1286 {
1287         int ret;
1288         struct ltt_kernel_channel *kchan;
1289
1290         assert(writer);
1291         assert(session);
1292
1293         ret = config_writer_write_element_string(writer, config_element_type,
1294                 config_domain_type_kernel);
1295         if (ret) {
1296                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1297                 goto end;
1298         }
1299
1300         ret = config_writer_write_element_string(writer,
1301                 config_element_buffer_type, config_buffer_type_global);
1302         if (ret) {
1303                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1304                 goto end;
1305         }
1306
1307         ret = config_writer_open_element(writer,
1308                 config_element_channels);
1309         if (ret) {
1310                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1311                 goto end;
1312         }
1313
1314         cds_list_for_each_entry(kchan, &session->kernel_session->channel_list.head,
1315                         list) {
1316                 ret = save_kernel_channel(writer, kchan);
1317                 if (ret) {
1318                         goto end;
1319                 }
1320         }
1321
1322         /* /channels */
1323         ret = config_writer_close_element(writer);
1324         if (ret) {
1325                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1326                 goto end;
1327         }
1328 end:
1329         return ret;
1330 }
1331
1332 static
1333 const char *get_config_domain_str(enum lttng_domain_type domain)
1334 {
1335         const char *str_dom;
1336
1337         switch (domain) {
1338         case LTTNG_DOMAIN_KERNEL:
1339                 str_dom = config_domain_type_kernel;
1340                 break;
1341         case LTTNG_DOMAIN_UST:
1342                 str_dom = config_domain_type_ust;
1343                 break;
1344         case LTTNG_DOMAIN_JUL:
1345                 str_dom = config_domain_type_jul;
1346                 break;
1347         case LTTNG_DOMAIN_LOG4J:
1348                 str_dom = config_domain_type_log4j;
1349                 break;
1350         case LTTNG_DOMAIN_PYTHON:
1351                 str_dom = config_domain_type_python;
1352                 break;
1353         default:
1354                 assert(0);
1355         }
1356
1357         return str_dom;
1358 }
1359
1360 static
1361 int save_pid_tracker(struct config_writer *writer,
1362         struct ltt_session *sess, int domain)
1363 {
1364         int ret = 0;
1365         ssize_t nr_pids = 0, i;
1366         int32_t *pids = NULL;
1367
1368         switch (domain) {
1369         case LTTNG_DOMAIN_KERNEL:
1370         {
1371                 nr_pids = kernel_list_tracker_pids(sess->kernel_session, &pids);
1372                 if (nr_pids < 0) {
1373                         ret = LTTNG_ERR_KERN_LIST_FAIL;
1374                         goto end;
1375                 }
1376                 break;
1377         }
1378         case LTTNG_DOMAIN_UST:
1379         {
1380                 nr_pids = trace_ust_list_tracker_pids(sess->ust_session, &pids);
1381                 if (nr_pids < 0) {
1382                         ret = LTTNG_ERR_UST_LIST_FAIL;
1383                         goto end;
1384                 }
1385                 break;
1386         }
1387         case LTTNG_DOMAIN_JUL:
1388         case LTTNG_DOMAIN_LOG4J:
1389         case LTTNG_DOMAIN_PYTHON:
1390         default:
1391                 ret = LTTNG_ERR_UNKNOWN_DOMAIN;
1392                 goto end;
1393         }
1394
1395         /* Only create a pid_tracker if enabled or untrack all */
1396         if (nr_pids != 1 || (nr_pids == 1 && pids[0] != -1)) {
1397                 ret = config_writer_open_element(writer,
1398                                 config_element_pid_tracker);
1399                 if (ret) {
1400                         ret = LTTNG_ERR_SAVE_IO_FAIL;
1401                         goto end;
1402                 }
1403
1404                 ret = config_writer_open_element(writer,
1405                                 config_element_targets);
1406                 if (ret) {
1407                         ret = LTTNG_ERR_SAVE_IO_FAIL;
1408                         goto end;
1409                 }
1410
1411                 for (i = 0; i < nr_pids; i++) {
1412                         ret = config_writer_open_element(writer,
1413                                         config_element_target_pid);
1414                         if (ret) {
1415                                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1416                                 goto end;
1417                         }
1418
1419                         ret = config_writer_write_element_unsigned_int(writer,
1420                                         config_element_pid, pids[i]);
1421                         if (ret) {
1422                                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1423                                 goto end;
1424                         }
1425
1426                         /* /pid_target */
1427                         ret = config_writer_close_element(writer);
1428                         if (ret) {
1429                                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1430                                 goto end;
1431                         }
1432                 }
1433
1434                 /* /targets */
1435                 ret = config_writer_close_element(writer);
1436                 if (ret) {
1437                         ret = LTTNG_ERR_SAVE_IO_FAIL;
1438                         goto end;
1439                 }
1440
1441                 /* /pid_tracker */
1442                 ret = config_writer_close_element(writer);
1443                 if (ret) {
1444                         ret = LTTNG_ERR_SAVE_IO_FAIL;
1445                         goto end;
1446                 }
1447         }
1448 end:
1449         free(pids);
1450         return ret;
1451 }
1452
1453 static
1454 int save_ust_domain(struct config_writer *writer,
1455         struct ltt_session *session, enum lttng_domain_type domain)
1456 {
1457         int ret;
1458         struct ltt_ust_channel *ust_chan;
1459         const char *buffer_type_string;
1460         struct lttng_ht_node_str *node;
1461         struct lttng_ht_iter iter;
1462         const char *config_domain_name;
1463
1464         assert(writer);
1465         assert(session);
1466
1467         ret = config_writer_open_element(writer,
1468                         config_element_domain);
1469         if (ret) {
1470                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1471                 goto end;
1472         }
1473
1474         config_domain_name = get_config_domain_str(domain);
1475         if (!config_domain_name) {
1476                 ret = LTTNG_ERR_INVALID;
1477                 goto end;
1478         }
1479
1480         ret = config_writer_write_element_string(writer,
1481                         config_element_type, config_domain_name);
1482         if (ret) {
1483                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1484                 goto end;
1485         }
1486
1487         buffer_type_string = get_buffer_type_string(
1488                         session->ust_session->buffer_type);
1489         if (!buffer_type_string) {
1490                 ERR("Unsupported buffer type.");
1491                 ret = LTTNG_ERR_INVALID;
1492                 goto end;
1493         }
1494
1495         ret = config_writer_write_element_string(writer,
1496                         config_element_buffer_type, buffer_type_string);
1497         if (ret) {
1498                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1499                 goto end;
1500         }
1501
1502         ret = config_writer_open_element(writer, config_element_channels);
1503         if (ret) {
1504                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1505                 goto end;
1506         }
1507
1508         rcu_read_lock();
1509         cds_lfht_for_each_entry(session->ust_session->domain_global.channels->ht,
1510                         &iter.iter, node, node) {
1511                 ust_chan = caa_container_of(node, struct ltt_ust_channel, node);
1512                 if (domain == ust_chan->domain) {
1513                         ret = save_ust_channel(writer, ust_chan, session->ust_session);
1514                         if (ret) {
1515                                 rcu_read_unlock();
1516                                 goto end;
1517                         }
1518                 }
1519         }
1520         rcu_read_unlock();
1521
1522         /* /channels */
1523         ret = config_writer_close_element(writer);
1524         if (ret) {
1525                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1526                 goto end;
1527         }
1528
1529         if (domain == LTTNG_DOMAIN_UST) {
1530                 ret = config_writer_open_element(writer,
1531                                 config_element_trackers);
1532                 if (ret) {
1533                         ret = LTTNG_ERR_SAVE_IO_FAIL;
1534                         goto end;
1535                 }
1536
1537                 ret = save_pid_tracker(writer, session, LTTNG_DOMAIN_UST);
1538                 if (ret) {
1539                         goto end;
1540                 }
1541
1542                 /* /trackers */
1543                 ret = config_writer_close_element(writer);
1544                 if (ret) {
1545                         goto end;
1546                 }
1547         }
1548
1549         /* /domain */
1550         ret = config_writer_close_element(writer);
1551         if (ret) {
1552                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1553                 goto end;
1554         }
1555
1556 end:
1557         return ret;
1558 }
1559
1560 static
1561 int save_domains(struct config_writer *writer, struct ltt_session *session)
1562 {
1563         int ret = 0;
1564
1565         assert(writer);
1566         assert(session);
1567
1568         if (!session->kernel_session && !session->ust_session) {
1569                 goto end;
1570         }
1571
1572         ret = config_writer_open_element(writer, config_element_domains);
1573         if (ret) {
1574                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1575                 goto end;
1576         }
1577
1578
1579         if (session->kernel_session) {
1580                 ret = config_writer_open_element(writer,
1581                         config_element_domain);
1582                 if (ret) {
1583                         ret = LTTNG_ERR_SAVE_IO_FAIL;
1584                         goto end;
1585                 }
1586
1587                 ret = save_kernel_session(writer, session);
1588                 if (ret) {
1589                         goto end;
1590                 }
1591
1592                 ret = config_writer_open_element(writer,
1593                         config_element_trackers);
1594                 if (ret) {
1595                         ret = LTTNG_ERR_SAVE_IO_FAIL;
1596                         goto end;
1597                 }
1598
1599                 ret = save_pid_tracker(writer, session, LTTNG_DOMAIN_KERNEL);
1600                 if (ret) {
1601                         goto end;
1602                 }
1603
1604                 /* /trackers */
1605                 ret = config_writer_close_element(writer);
1606                 if (ret) {
1607                         ret = LTTNG_ERR_SAVE_IO_FAIL;
1608                         goto end;
1609                 }
1610                 /* /domain */
1611                 ret = config_writer_close_element(writer);
1612                 if (ret) {
1613                         ret = LTTNG_ERR_SAVE_IO_FAIL;
1614                         goto end;
1615                 }
1616         }
1617
1618         if (session->ust_session) {
1619                 ret = save_ust_domain(writer, session, LTTNG_DOMAIN_UST);
1620                 if (ret) {
1621                         goto end;
1622                 }
1623
1624                 ret = save_ust_domain(writer, session, LTTNG_DOMAIN_JUL);
1625                 if (ret) {
1626                         goto end;
1627                 }
1628
1629                 ret = save_ust_domain(writer, session, LTTNG_DOMAIN_LOG4J);
1630                 if (ret) {
1631                         goto end;
1632                 }
1633
1634                 ret = save_ust_domain(writer, session, LTTNG_DOMAIN_PYTHON);
1635                 if (ret) {
1636                         goto end;
1637                 }
1638         }
1639
1640         /* /domains */
1641         ret = config_writer_close_element(writer);
1642         if (ret) {
1643                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1644                 goto end;
1645         }
1646 end:
1647         return ret;
1648 }
1649
1650 static
1651 int save_consumer_output(struct config_writer *writer,
1652         struct consumer_output *output)
1653 {
1654         int ret;
1655
1656         assert(writer);
1657         assert(output);
1658
1659         ret = config_writer_open_element(writer, config_element_consumer_output);
1660         if (ret) {
1661                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1662                 goto end;
1663         }
1664
1665         ret = config_writer_write_element_bool(writer, config_element_enabled,
1666                         output->enabled);
1667         if (ret) {
1668                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1669                 goto end;
1670         }
1671
1672         ret = config_writer_open_element(writer, config_element_destination);
1673         if (ret) {
1674                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1675                 goto end;
1676         }
1677
1678         switch (output->type) {
1679         case CONSUMER_DST_LOCAL:
1680                 ret = config_writer_write_element_string(writer,
1681                         config_element_path, output->dst.session_root_path);
1682                 if (ret) {
1683                         ret = LTTNG_ERR_SAVE_IO_FAIL;
1684                         goto end;
1685                 }
1686                 break;
1687         case CONSUMER_DST_NET:
1688         {
1689                 char *uri;
1690
1691                 uri = zmalloc(PATH_MAX);
1692                 if (!uri) {
1693                         ret = LTTNG_ERR_NOMEM;
1694                         goto end;
1695                 }
1696
1697                 ret = config_writer_open_element(writer, config_element_net_output);
1698                 if (ret) {
1699                         ret = LTTNG_ERR_SAVE_IO_FAIL;
1700                         goto end_net_output;
1701                 }
1702
1703                 if (output->dst.net.control_isset &&
1704                         output->dst.net.data_isset) {
1705                         ret = uri_to_str_url(&output->dst.net.control, uri, PATH_MAX);
1706                         if (ret < 0) {
1707                                 ret = LTTNG_ERR_INVALID;
1708                                 goto end_net_output;
1709                         }
1710
1711                         ret = config_writer_write_element_string(writer,
1712                                         config_element_control_uri, uri);
1713                         if (ret) {
1714                                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1715                                 goto end_net_output;
1716                         }
1717
1718                         ret = uri_to_str_url(&output->dst.net.data, uri, PATH_MAX);
1719                         if (ret < 0) {
1720                                 ret = LTTNG_ERR_INVALID;
1721                                 goto end_net_output;
1722                         }
1723
1724                         ret = config_writer_write_element_string(writer,
1725                                         config_element_data_uri, uri);
1726                         if (ret) {
1727                                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1728                                 goto end_net_output;
1729                         }
1730
1731 end_net_output:
1732                         free(uri);
1733                         if (ret) {
1734                                 goto end;
1735                         }
1736                 } else {
1737                         ret = !output->dst.net.control_isset ?
1738                                 LTTNG_ERR_URL_CTRL_MISS :
1739                                 LTTNG_ERR_URL_DATA_MISS;
1740                         free(uri);
1741                         goto end;
1742                 }
1743
1744                 ret = config_writer_close_element(writer);
1745                 if (ret) {
1746                         ret = LTTNG_ERR_SAVE_IO_FAIL;
1747                         goto end;
1748                 }
1749                 break;
1750         }
1751         default:
1752                 ERR("Unsupported consumer output type.");
1753                 ret = LTTNG_ERR_INVALID;
1754                 goto end;
1755         }
1756
1757         /* /destination */
1758         ret = config_writer_close_element(writer);
1759         if (ret) {
1760                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1761                 goto end;
1762         }
1763
1764         /* /consumer_output */
1765         ret = config_writer_close_element(writer);
1766         if (ret) {
1767                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1768                 goto end;
1769         }
1770 end:
1771         return ret;
1772 }
1773
1774 static
1775 int save_snapshot_outputs(struct config_writer *writer,
1776         struct snapshot *snapshot)
1777 {
1778         int ret;
1779         struct lttng_ht_iter iter;
1780         struct snapshot_output *output;
1781
1782         assert(writer);
1783         assert(snapshot);
1784
1785         ret = config_writer_open_element(writer, config_element_snapshot_outputs);
1786         if (ret) {
1787                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1788                 goto end;
1789         }
1790
1791         rcu_read_lock();
1792         cds_lfht_for_each_entry(snapshot->output_ht->ht, &iter.iter, output,
1793                         node.node) {
1794                 ret = config_writer_open_element(writer,
1795                         config_element_output);
1796                 if (ret) {
1797                         ret = LTTNG_ERR_SAVE_IO_FAIL;
1798                         goto end_unlock;
1799                 }
1800
1801                 ret = config_writer_write_element_string(writer,
1802                         config_element_name, output->name);
1803                 if (ret) {
1804                         ret = LTTNG_ERR_SAVE_IO_FAIL;
1805                         goto end_unlock;
1806                 }
1807
1808                 ret = config_writer_write_element_unsigned_int(writer,
1809                         config_element_max_size, output->max_size);
1810                 if (ret) {
1811                         ret = LTTNG_ERR_SAVE_IO_FAIL;
1812                         goto end_unlock;
1813                 }
1814
1815                 ret = save_consumer_output(writer, output->consumer);
1816                 if (ret) {
1817                         goto end_unlock;
1818                 }
1819
1820                 /* /output */
1821                 ret = config_writer_close_element(writer);
1822                 if (ret) {
1823                         ret = LTTNG_ERR_SAVE_IO_FAIL;
1824                         goto end_unlock;
1825                 }
1826         }
1827         rcu_read_unlock();
1828
1829         /* /snapshot_outputs */
1830         ret = config_writer_close_element(writer);
1831         if (ret) {
1832                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1833                 goto end;
1834         }
1835
1836 end:
1837         return ret;
1838 end_unlock:
1839         rcu_read_unlock();
1840         return ret;
1841 }
1842
1843 static
1844 int save_session_output(struct config_writer *writer,
1845         struct ltt_session *session)
1846 {
1847         int ret;
1848
1849         assert(writer);
1850         assert(session);
1851
1852         if ((session->snapshot_mode && session->snapshot.nb_output == 0) ||
1853                 (!session->snapshot_mode && !session->consumer)) {
1854                 /* Session is in no output mode */
1855                 ret = 0;
1856                 goto end;
1857         }
1858
1859         ret = config_writer_open_element(writer, config_element_output);
1860         if (ret) {
1861                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1862                 goto end;
1863         }
1864
1865         if (session->snapshot_mode) {
1866                 ret = save_snapshot_outputs(writer, &session->snapshot);
1867                 if (ret) {
1868                         goto end;
1869                 }
1870         } else {
1871                 if (session->consumer) {
1872                         ret = save_consumer_output(writer, session->consumer);
1873                         if (ret) {
1874                                 goto end;
1875                         }
1876                 }
1877         }
1878
1879         /* /output */
1880         ret = config_writer_close_element(writer);
1881         if (ret) {
1882                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1883                 goto end;
1884         }
1885 end:
1886         return ret;
1887 }
1888
1889 /*
1890  * Save the given session.
1891  *
1892  * Return 0 on success else a LTTNG_ERR* code.
1893  */
1894 static
1895 int save_session(struct ltt_session *session,
1896         struct lttng_save_session_attr *attr, lttng_sock_cred *creds)
1897 {
1898         int ret, fd;
1899         unsigned int file_opened = 0;   /* Indicate if the file has been opened */
1900         char config_file_path[PATH_MAX];
1901         size_t len;
1902         struct config_writer *writer = NULL;
1903         size_t session_name_len;
1904         const char *provided_path;
1905
1906         assert(session);
1907         assert(attr);
1908         assert(creds);
1909
1910         session_name_len = strlen(session->name);
1911         memset(config_file_path, 0, sizeof(config_file_path));
1912
1913         if (!session_access_ok(session,
1914                 LTTNG_SOCK_GET_UID_CRED(creds),
1915                 LTTNG_SOCK_GET_GID_CRED(creds))) {
1916                 ret = LTTNG_ERR_EPERM;
1917                 goto end;
1918         }
1919
1920         provided_path = lttng_save_session_attr_get_output_url(attr);
1921         if (provided_path) {
1922                 DBG3("Save session in provided path %s", provided_path);
1923                 len = strlen(provided_path);
1924                 if (len >= sizeof(config_file_path)) {
1925                         ret = LTTNG_ERR_SET_URL;
1926                         goto end;
1927                 }
1928                 strncpy(config_file_path, provided_path, len);
1929         } else {
1930                 ssize_t ret_len;
1931                 char *home_dir = utils_get_user_home_dir(
1932                         LTTNG_SOCK_GET_UID_CRED(creds));
1933                 if (!home_dir) {
1934                         ret = LTTNG_ERR_SET_URL;
1935                         goto end;
1936                 }
1937
1938                 ret_len = snprintf(config_file_path, sizeof(config_file_path),
1939                                 DEFAULT_SESSION_HOME_CONFIGPATH, home_dir);
1940                 free(home_dir);
1941                 if (ret_len < 0) {
1942                         PERROR("snprintf save session");
1943                         ret = LTTNG_ERR_SET_URL;
1944                         goto end;
1945                 }
1946                 len = ret_len;
1947         }
1948
1949         /*
1950          * Check the path fits in the config file path dst including the '/'
1951          * followed by trailing .lttng extension and the NULL terminated string.
1952          */
1953         if ((len + session_name_len + 2 +
1954                         sizeof(DEFAULT_SESSION_CONFIG_FILE_EXTENSION))
1955                         > sizeof(config_file_path)) {
1956                 ret = LTTNG_ERR_SET_URL;
1957                 goto end;
1958         }
1959
1960         ret = run_as_mkdir_recursive(config_file_path, S_IRWXU | S_IRWXG,
1961                         LTTNG_SOCK_GET_UID_CRED(creds), LTTNG_SOCK_GET_GID_CRED(creds));
1962         if (ret) {
1963                 ret = LTTNG_ERR_SET_URL;
1964                 goto end;
1965         }
1966
1967         /*
1968          * At this point, we know that everything fits in the buffer. Validation
1969          * was done just above.
1970          */
1971         config_file_path[len++] = '/';
1972         strncpy(config_file_path + len, session->name, session_name_len);
1973         len += session_name_len;
1974         strcpy(config_file_path + len, DEFAULT_SESSION_CONFIG_FILE_EXTENSION);
1975         len += sizeof(DEFAULT_SESSION_CONFIG_FILE_EXTENSION);
1976         config_file_path[len] = '\0';
1977
1978         if (!access(config_file_path, F_OK) && !attr->overwrite) {
1979                 /* File exists, notify the user since the overwrite flag is off. */
1980                 ret = LTTNG_ERR_SAVE_FILE_EXIST;
1981                 goto end;
1982         }
1983
1984         fd = run_as_open(config_file_path, O_CREAT | O_WRONLY | O_TRUNC,
1985                 S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP,
1986                 LTTNG_SOCK_GET_UID_CRED(creds), LTTNG_SOCK_GET_GID_CRED(creds));
1987         if (fd < 0) {
1988                 PERROR("Could not create configuration file");
1989                 ret = LTTNG_ERR_SAVE_IO_FAIL;
1990                 goto end;
1991         }
1992         file_opened = 1;
1993
1994         writer = config_writer_create(fd, 1);
1995         if (!writer) {
1996                 ret = LTTNG_ERR_NOMEM;
1997                 goto end;
1998         }
1999
2000         ret = config_writer_open_element(writer, config_element_sessions);
2001         if (ret) {
2002                 ret = LTTNG_ERR_SAVE_IO_FAIL;
2003                 goto end;
2004         }
2005
2006         ret = config_writer_open_element(writer, config_element_session);
2007         if (ret) {
2008                 ret = LTTNG_ERR_SAVE_IO_FAIL;
2009                 goto end;
2010         }
2011
2012         ret = config_writer_write_element_string(writer, config_element_name,
2013                         session->name);
2014         if (ret) {
2015                 ret = LTTNG_ERR_SAVE_IO_FAIL;
2016                 goto end;
2017         }
2018
2019         if(session->shm_path[0] != '\0') {
2020                 ret = config_writer_write_element_string(writer,
2021                                 config_element_shared_memory_path,
2022                                 session->shm_path);
2023                 if (ret) {
2024                         ret = LTTNG_ERR_SAVE_IO_FAIL;
2025                         goto end;
2026                 }
2027         }
2028
2029         ret = save_domains(writer, session);
2030         if (ret) {
2031                 goto end;
2032         }
2033
2034         ret = config_writer_write_element_bool(writer, config_element_started,
2035                         session->active);
2036         if (ret) {
2037                 ret = LTTNG_ERR_SAVE_IO_FAIL;
2038                 goto end;
2039         }
2040
2041         if (session->snapshot_mode || session->live_timer ||
2042                         session->rotate_timer_period || session->rotate_size) {
2043                 ret = config_writer_open_element(writer, config_element_attributes);
2044                 if (ret) {
2045                         ret = LTTNG_ERR_SAVE_IO_FAIL;
2046                         goto end;
2047                 }
2048
2049                 if (session->snapshot_mode) {
2050                         ret = config_writer_write_element_bool(writer,
2051                                         config_element_snapshot_mode, 1);
2052                         if (ret) {
2053                                 ret = LTTNG_ERR_SAVE_IO_FAIL;
2054                                 goto end;
2055                         }
2056                 } else if (session->live_timer) {
2057                         ret = config_writer_write_element_unsigned_int(writer,
2058                                         config_element_live_timer_interval, session->live_timer);
2059                         if (ret) {
2060                                 ret = LTTNG_ERR_SAVE_IO_FAIL;
2061                                 goto end;
2062                         }
2063                 }
2064                 if (session->rotate_timer_period) {
2065                         ret = config_writer_write_element_unsigned_int(writer,
2066                                         config_element_rotation_timer_interval,
2067                                         session->rotate_timer_period);
2068                         if (ret) {
2069                                 ret = LTTNG_ERR_SAVE_IO_FAIL;
2070                                 goto end;
2071                         }
2072                 }
2073
2074                 if (session->rotate_size) {
2075                         ret = config_writer_write_element_unsigned_int(writer,
2076                                         config_element_rotation_size,
2077                                         session->rotate_size);
2078                         if (ret) {
2079                                 ret = LTTNG_ERR_SAVE_IO_FAIL;
2080                                 goto end;
2081                         }
2082                 }
2083
2084                 /* /attributes */
2085                 ret = config_writer_close_element(writer);
2086                 if (ret) {
2087                         ret = LTTNG_ERR_SAVE_IO_FAIL;
2088                         goto end;
2089                 }
2090         }
2091
2092         ret = save_session_output(writer, session);
2093         if (ret) {
2094                 goto end;
2095         }
2096
2097         /* /session */
2098         ret = config_writer_close_element(writer);
2099         if (ret) {
2100                 ret = LTTNG_ERR_SAVE_IO_FAIL;
2101                 goto end;
2102         }
2103
2104         /* /sessions */
2105         ret = config_writer_close_element(writer);
2106         if (ret) {
2107                 ret = LTTNG_ERR_SAVE_IO_FAIL;
2108                 goto end;
2109         }
2110 end:
2111         if (writer && config_writer_destroy(writer)) {
2112                 /* Preserve the original error code */
2113                 ret = ret ? ret : LTTNG_ERR_SAVE_IO_FAIL;
2114         }
2115         if (ret) {
2116                 /* Delete file in case of error */
2117                 if (file_opened && unlink(config_file_path)) {
2118                         PERROR("Unlinking XML session configuration.");
2119                 }
2120         }
2121
2122         if (file_opened) {
2123                 ret = close(fd);
2124                 if (ret) {
2125                         PERROR("Closing XML session configuration");
2126                 }
2127         }
2128
2129         return ret;
2130 }
2131
2132 int cmd_save_sessions(struct lttng_save_session_attr *attr,
2133         lttng_sock_cred *creds)
2134 {
2135         int ret;
2136         const char *session_name;
2137         struct ltt_session *session;
2138
2139         session_lock_list();
2140
2141         session_name = lttng_save_session_attr_get_session_name(attr);
2142         if (session_name) {
2143                 session = session_find_by_name(session_name);
2144                 if (!session) {
2145                         ret = LTTNG_ERR_SESS_NOT_FOUND;
2146                         goto end;
2147                 }
2148
2149                 session_lock(session);
2150                 ret = save_session(session, attr, creds);
2151                 session_unlock(session);
2152                 if (ret) {
2153                         goto end;
2154                 }
2155         } else {
2156                 struct ltt_session_list *list = session_get_list();
2157
2158                 cds_list_for_each_entry(session, &list->head, list) {
2159                         session_lock(session);
2160                         ret = save_session(session, attr, creds);
2161                         session_unlock(session);
2162
2163                         /* Don't abort if we don't have the required permissions. */
2164                         if (ret && ret != LTTNG_ERR_EPERM) {
2165                                 goto end;
2166                         }
2167                 }
2168         }
2169         ret = LTTNG_OK;
2170
2171 end:
2172         session_unlock_list();
2173         return ret;
2174 }