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