src/bin/lttng-sessiond/trace-kernel.c

   1 /*
   2  * Copyright (C)  2011 - David Goulet <david.goulet@polymtl.ca>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License, version 2 only,
   6  * as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #define _GNU_SOURCE
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <string.h>
  22 #include <unistd.h>
  23
  24 #include <common/common.h>
  25 #include <common/defaults.h>
  26
  27 #include "consumer.h"
  28 #include "trace-kernel.h"
  29
  30 /*
  31  * Find the channel name for the given kernel session.
  32  */
  33 struct ltt_kernel_channel *trace_kernel_get_channel_by_name(
  34                 char *name, struct ltt_kernel_session *session)
  35 {
  36         struct ltt_kernel_channel *chan;
  37
  38         if (session == NULL) {
  39                 ERR("Undefine session");
  40                 goto error;
  41         }
  42
  43         DBG("Trying to find channel %s", name);
  44
  45         cds_list_for_each_entry(chan, &session->channel_list.head, list) {
  46                 if (strcmp(name, chan->channel->name) == 0) {
  47                         DBG("Found channel by name %s", name);
  48                         return chan;
  49                 }
  50         }
  51
  52 error:
  53         return NULL;
  54 }
  55
  56 /*
  57  * Find the event name for the given channel.
  58  */
  59 struct ltt_kernel_event *trace_kernel_get_event_by_name(
  60                 char *name, struct ltt_kernel_channel *channel)
  61 {
  62         struct ltt_kernel_event *ev;
  63
  64         if (channel == NULL) {
  65                 ERR("Undefine channel");
  66                 goto error;
  67         }
  68
  69         cds_list_for_each_entry(ev, &channel->events_list.head, list) {
  70                 if (strcmp(name, ev->event->name) == 0) {
  71                         DBG("Found event by name %s for channel %s", name,
  72                                         channel->channel->name);
  73                         return ev;
  74                 }
  75         }
  76
  77 error:
  78         return NULL;
  79 }
  80
  81 /*
  82  * Allocate and initialize a kernel session data structure.
  83  *
  84  * Return pointer to structure or NULL.
  85  */
  86 struct ltt_kernel_session *trace_kernel_create_session(char *path)
  87 {
  88         struct ltt_kernel_session *lks = NULL;
  89
  90         /* Allocate a new ltt kernel session */
  91         lks = zmalloc(sizeof(struct ltt_kernel_session));
  92         if (lks == NULL) {
  93                 PERROR("create kernel session zmalloc");
  94                 goto alloc_error;
  95         }
  96
  97         /* Init data structure */
  98         lks->fd = -1;
  99         lks->metadata_stream_fd = -1;
 100         lks->channel_count = 0;
 101         lks->stream_count_global = 0;
 102         lks->metadata = NULL;
 103         CDS_INIT_LIST_HEAD(&lks->channel_list.head);
 104
 105         lks->consumer = consumer_create_output(CONSUMER_DST_LOCAL);
 106         if (lks->consumer == NULL) {
 107                 goto error;
 108         }
 109
 110         /*
 111          * The tmp_consumer stays NULL until a set_consumer_uri command is
 112          * executed. At this point, the consumer should be nullify until an
 113          * enable_consumer command. This assignment is symbolic since we've zmalloc
 114          * the struct.
 115          */
 116         lks->tmp_consumer = NULL;
 117
 118         if (path && strlen(path) > 0) {
 119                 int ret;
 120
 121                 /* Use the default consumer output which is the tracing session path. */
 122                 ret = snprintf(lks->consumer->dst.trace_path, PATH_MAX,
 123                                 "%s" DEFAULT_KERNEL_TRACE_DIR, path);
 124                 if (ret < 0) {
 125                         PERROR("snprintf consumer trace path");
 126                         goto error;
 127                 }
 128
 129                 /* Set session path */
 130                 ret = asprintf(&lks->trace_path, "%s" DEFAULT_KERNEL_TRACE_DIR, path);
 131                 if (ret < 0) {
 132                         PERROR("asprintf kernel traces path");
 133                         goto error;
 134                 }
 135         }
 136
 137         return lks;
 138
 139 error:
 140         free(lks);
 141
 142 alloc_error:
 143         return NULL;
 144 }
 145
 146 /*
 147  * Allocate and initialize a kernel channel data structure.
 148  *
 149  * Return pointer to structure or NULL.
 150  */
 151 struct ltt_kernel_channel *trace_kernel_create_channel(
 152                 struct lttng_channel *chan, char *path)
 153 {
 154         struct ltt_kernel_channel *lkc;
 155
 156         lkc = zmalloc(sizeof(struct ltt_kernel_channel));
 157         if (lkc == NULL) {
 158                 PERROR("ltt_kernel_channel zmalloc");
 159                 goto error;
 160         }
 161
 162         lkc->channel = zmalloc(sizeof(struct lttng_channel));
 163         if (lkc->channel == NULL) {
 164                 PERROR("lttng_channel zmalloc");
 165                 goto error;
 166         }
 167         memcpy(lkc->channel, chan, sizeof(struct lttng_channel));
 168
 169         lkc->fd = -1;
 170         lkc->stream_count = 0;
 171         lkc->event_count = 0;
 172         lkc->enabled = 1;
 173         lkc->ctx = NULL;
 174         /* Init linked list */
 175         CDS_INIT_LIST_HEAD(&lkc->events_list.head);
 176         CDS_INIT_LIST_HEAD(&lkc->stream_list.head);
 177
 178         return lkc;
 179
 180 error:
 181         return NULL;
 182 }
 183
 184 /*
 185  * Allocate and initialize a kernel event. Set name and event type.
 186  *
 187  * Return pointer to structure or NULL.
 188  */
 189 struct ltt_kernel_event *trace_kernel_create_event(struct lttng_event *ev)
 190 {
 191         struct ltt_kernel_event *lke;
 192         struct lttng_kernel_event *attr;
 193
 194         lke = zmalloc(sizeof(struct ltt_kernel_event));
 195         attr = zmalloc(sizeof(struct lttng_kernel_event));
 196         if (lke == NULL || attr == NULL) {
 197                 PERROR("kernel event zmalloc");
 198                 goto error;
 199         }
 200
 201         switch (ev->type) {
 202         case LTTNG_EVENT_PROBE:
 203                 attr->instrumentation = LTTNG_KERNEL_KPROBE;
 204                 attr->u.kprobe.addr = ev->attr.probe.addr;
 205                 attr->u.kprobe.offset = ev->attr.probe.offset;
 206                 strncpy(attr->u.kprobe.symbol_name,
 207                                 ev->attr.probe.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 208                 attr->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 209                 break;
 210         case LTTNG_EVENT_FUNCTION:
 211                 attr->instrumentation = LTTNG_KERNEL_KRETPROBE;
 212                 attr->u.kretprobe.addr = ev->attr.probe.addr;
 213                 attr->u.kretprobe.offset = ev->attr.probe.offset;
 214                 attr->u.kretprobe.offset = ev->attr.probe.offset;
 215                 strncpy(attr->u.kretprobe.symbol_name,
 216                                 ev->attr.probe.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 217                 attr->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 218                 break;
 219         case LTTNG_EVENT_FUNCTION_ENTRY:
 220                 attr->instrumentation = LTTNG_KERNEL_FUNCTION;
 221                 strncpy(attr->u.ftrace.symbol_name,
 222                                 ev->attr.ftrace.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 223                 attr->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 224                 break;
 225         case LTTNG_EVENT_TRACEPOINT:
 226                 attr->instrumentation = LTTNG_KERNEL_TRACEPOINT;
 227                 break;
 228         case LTTNG_EVENT_SYSCALL:
 229                 attr->instrumentation = LTTNG_KERNEL_SYSCALL;
 230                 break;
 231         case LTTNG_EVENT_ALL:
 232                 attr->instrumentation = LTTNG_KERNEL_ALL;
 233                 break;
 234         default:
 235                 ERR("Unknown kernel instrumentation type (%d)", ev->type);
 236                 goto error;
 237         }
 238
 239         /* Copy event name */
 240         strncpy(attr->name, ev->name, LTTNG_KERNEL_SYM_NAME_LEN);
 241         attr->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 242
 243         /* Setting up a kernel event */
 244         lke->fd = -1;
 245         lke->event = attr;
 246         lke->enabled = 1;
 247
 248         return lke;
 249
 250 error:
 251         free(lke);
 252         free(attr);
 253         return NULL;
 254 }
 255
 256 /*
 257  * Allocate and initialize a kernel metadata.
 258  *
 259  * Return pointer to structure or NULL.
 260  */
 261 struct ltt_kernel_metadata *trace_kernel_create_metadata(void)
 262 {
 263         struct ltt_kernel_metadata *lkm;
 264         struct lttng_channel *chan;
 265
 266         lkm = zmalloc(sizeof(struct ltt_kernel_metadata));
 267         chan = zmalloc(sizeof(struct lttng_channel));
 268         if (lkm == NULL || chan == NULL) {
 269                 PERROR("kernel metadata zmalloc");
 270                 goto error;
 271         }
 272
 273         /* Set default attributes */
 274         chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
 275         chan->attr.subbuf_size = default_get_metadata_subbuf_size();
 276         chan->attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM;
 277         chan->attr.switch_timer_interval = DEFAULT_CHANNEL_SWITCH_TIMER;
 278         chan->attr.read_timer_interval = DEFAULT_CHANNEL_READ_TIMER;
 279         chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
 280
 281         /* Init metadata */
 282         lkm->fd = -1;
 283         lkm->conf = chan;
 284
 285         return lkm;
 286
 287 error:
 288         free(lkm);
 289         free(chan);
 290         return NULL;
 291 }
 292
 293 /*
 294  * Allocate and initialize a kernel stream. The stream is set to ACTIVE_FD by
 295  * default.
 296  *
 297  * Return pointer to structure or NULL.
 298  */
 299 struct ltt_kernel_stream *trace_kernel_create_stream(const char *name,
 300                 unsigned int count)
 301 {
 302         int ret;
 303         struct ltt_kernel_stream *lks;
 304
 305         lks = zmalloc(sizeof(struct ltt_kernel_stream));
 306         if (lks == NULL) {
 307                 PERROR("kernel stream zmalloc");
 308                 goto error;
 309         }
 310
 311         /* Set name */
 312         ret = snprintf(lks->name, sizeof(lks->name), "%s_%d", name, count);
 313         if (ret < 0) {
 314                 PERROR("snprintf stream name");
 315                 goto error;
 316         }
 317         lks->name[sizeof(lks->name) - 1] = '\0';
 318
 319         /* Init stream */
 320         lks->fd = -1;
 321         lks->state = 0;
 322
 323         return lks;
 324
 325 error:
 326         return NULL;
 327 }
 328
 329 /*
 330  * Cleanup kernel stream structure.
 331  */
 332 void trace_kernel_destroy_stream(struct ltt_kernel_stream *stream)
 333 {
 334         DBG("[trace] Closing stream fd %d", stream->fd);
 335         /* Close kernel fd */
 336         if (stream->fd >= 0) {
 337                 int ret;
 338
 339                 ret = close(stream->fd);
 340                 if (ret) {
 341                         PERROR("close");
 342                 }
 343         }
 344         /* Remove from stream list */
 345         cds_list_del(&stream->list);
 346
 347         free(stream);
 348 }
 349
 350 /*
 351  * Cleanup kernel event structure.
 352  */
 353 void trace_kernel_destroy_event(struct ltt_kernel_event *event)
 354 {
 355         if (event->fd >= 0) {
 356                 int ret;
 357
 358                 DBG("[trace] Closing event fd %d", event->fd);
 359                 /* Close kernel fd */
 360                 ret = close(event->fd);
 361                 if (ret) {
 362                         PERROR("close");
 363                 }
 364         } else {
 365                 DBG("[trace] Tearing down event (no associated fd)");
 366         }
 367
 368         /* Remove from event list */
 369         cds_list_del(&event->list);
 370
 371         free(event->event);
 372         free(event);
 373 }
 374
 375 /*
 376  * Cleanup kernel channel structure.
 377  */
 378 void trace_kernel_destroy_channel(struct ltt_kernel_channel *channel)
 379 {
 380         struct ltt_kernel_stream *stream, *stmp;
 381         struct ltt_kernel_event *event, *etmp;
 382         int ret;
 383
 384         DBG("[trace] Closing channel fd %d", channel->fd);
 385         /* Close kernel fd */
 386         if (channel->fd >= 0) {
 387                 ret = close(channel->fd);
 388                 if (ret) {
 389                         PERROR("close");
 390                 }
 391         }
 392
 393         /* For each stream in the channel list */
 394         cds_list_for_each_entry_safe(stream, stmp, &channel->stream_list.head, list) {
 395                 trace_kernel_destroy_stream(stream);
 396         }
 397
 398         /* For each event in the channel list */
 399         cds_list_for_each_entry_safe(event, etmp, &channel->events_list.head, list) {
 400                 trace_kernel_destroy_event(event);
 401         }
 402
 403         /* Remove from channel list */
 404         cds_list_del(&channel->list);
 405
 406         free(channel->channel);
 407         free(channel->ctx);
 408         free(channel);
 409 }
 410
 411 /*
 412  * Cleanup kernel metadata structure.
 413  */
 414 void trace_kernel_destroy_metadata(struct ltt_kernel_metadata *metadata)
 415 {
 416         DBG("[trace] Closing metadata fd %d", metadata->fd);
 417         /* Close kernel fd */
 418         if (metadata->fd >= 0) {
 419                 int ret;
 420
 421                 ret = close(metadata->fd);
 422                 if (ret) {
 423                         PERROR("close");
 424                 }
 425         }
 426
 427         free(metadata->conf);
 428         free(metadata);
 429 }
 430
 431 /*
 432  * Cleanup kernel session structure
 433  */
 434 void trace_kernel_destroy_session(struct ltt_kernel_session *session)
 435 {
 436         struct ltt_kernel_channel *channel, *ctmp;
 437         int ret;
 438
 439         DBG("[trace] Closing session fd %d", session->fd);
 440         /* Close kernel fds */
 441         if (session->fd >= 0) {
 442                 ret = close(session->fd);
 443                 if (ret) {
 444                         PERROR("close");
 445                 }
 446         }
 447
 448         if (session->metadata_stream_fd >= 0) {
 449                 DBG("[trace] Closing metadata stream fd %d", session->metadata_stream_fd);
 450                 ret = close(session->metadata_stream_fd);
 451                 if (ret) {
 452                         PERROR("close");
 453                 }
 454         }
 455
 456         if (session->metadata != NULL) {
 457                 trace_kernel_destroy_metadata(session->metadata);
 458         }
 459
 460         cds_list_for_each_entry_safe(channel, ctmp, &session->channel_list.head, list) {
 461                 trace_kernel_destroy_channel(channel);
 462         }
 463
 464         /* Wipe consumer output object */
 465         consumer_destroy_output(session->consumer);
 466         consumer_destroy_output(session->tmp_consumer);
 467
 468         free(session->trace_path);
 469         free(session);
 470 }