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         int ret;
  89         struct ltt_kernel_session *lks;
  90
  91         /* Allocate a new ltt kernel session */
  92         lks = zmalloc(sizeof(struct ltt_kernel_session));
  93         if (lks == NULL) {
  94                 PERROR("create kernel session zmalloc");
  95                 goto error;
  96         }
  97
  98         /* Init data structure */
  99         lks->fd = -1;
 100         lks->metadata_stream_fd = -1;
 101         lks->channel_count = 0;
 102         lks->stream_count_global = 0;
 103         lks->metadata = NULL;
 104         lks->consumer_fd = -1;
 105         CDS_INIT_LIST_HEAD(&lks->channel_list.head);
 106
 107         /* Create default consumer output object */
 108         lks->consumer = consumer_create_output(CONSUMER_DST_LOCAL);
 109         if (lks->consumer == NULL) {
 110                 goto error;
 111         }
 112
 113         /*
 114          * The tmp_consumer stays NULL until a set_consumer_uri command is
 115          * executed. At this point, the consumer should be nullify until an
 116          * enable_consumer command. This assignment is symbolic since we've zmalloc
 117          * the struct.
 118          */
 119         lks->tmp_consumer = NULL;
 120
 121         /* Use the default consumer output which is the tracing session path. */
 122         ret = snprintf(lks->consumer->dst.trace_path, PATH_MAX, "%s/kernel", path);
 123         if (ret < 0) {
 124                 PERROR("snprintf consumer trace path");
 125                 goto error;
 126         }
 127
 128         /* Set session path */
 129         ret = asprintf(&lks->trace_path, "%s/kernel", path);
 130         if (ret < 0) {
 131                 PERROR("asprintf kernel traces path");
 132                 goto error;
 133         }
 134
 135         return lks;
 136
 137 error:
 138         return NULL;
 139 }
 140
 141 /*
 142  * Allocate and initialize a kernel channel data structure.
 143  *
 144  * Return pointer to structure or NULL.
 145  */
 146 struct ltt_kernel_channel *trace_kernel_create_channel(
 147                 struct lttng_channel *chan, char *path)
 148 {
 149         struct ltt_kernel_channel *lkc;
 150
 151         lkc = zmalloc(sizeof(struct ltt_kernel_channel));
 152         if (lkc == NULL) {
 153                 PERROR("ltt_kernel_channel zmalloc");
 154                 goto error;
 155         }
 156
 157         lkc->channel = zmalloc(sizeof(struct lttng_channel));
 158         if (lkc->channel == NULL) {
 159                 PERROR("lttng_channel zmalloc");
 160                 goto error;
 161         }
 162         memcpy(lkc->channel, chan, sizeof(struct lttng_channel));
 163
 164         lkc->fd = -1;
 165         lkc->stream_count = 0;
 166         lkc->event_count = 0;
 167         lkc->enabled = 1;
 168         lkc->ctx = NULL;
 169         /* Init linked list */
 170         CDS_INIT_LIST_HEAD(&lkc->events_list.head);
 171         CDS_INIT_LIST_HEAD(&lkc->stream_list.head);
 172
 173         return lkc;
 174
 175 error:
 176         return NULL;
 177 }
 178
 179 /*
 180  * Allocate and initialize a kernel event. Set name and event type.
 181  *
 182  * Return pointer to structure or NULL.
 183  */
 184 struct ltt_kernel_event *trace_kernel_create_event(struct lttng_event *ev)
 185 {
 186         struct ltt_kernel_event *lke;
 187         struct lttng_kernel_event *attr;
 188
 189         lke = zmalloc(sizeof(struct ltt_kernel_event));
 190         attr = zmalloc(sizeof(struct lttng_kernel_event));
 191         if (lke == NULL || attr == NULL) {
 192                 PERROR("kernel event zmalloc");
 193                 goto error;
 194         }
 195
 196         switch (ev->type) {
 197         case LTTNG_EVENT_PROBE:
 198                 attr->instrumentation = LTTNG_KERNEL_KPROBE;
 199                 attr->u.kprobe.addr = ev->attr.probe.addr;
 200                 attr->u.kprobe.offset = ev->attr.probe.offset;
 201                 strncpy(attr->u.kprobe.symbol_name,
 202                                 ev->attr.probe.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 203                 attr->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 204                 break;
 205         case LTTNG_EVENT_FUNCTION:
 206                 attr->instrumentation = LTTNG_KERNEL_KRETPROBE;
 207                 attr->u.kretprobe.addr = ev->attr.probe.addr;
 208                 attr->u.kretprobe.offset = ev->attr.probe.offset;
 209                 attr->u.kretprobe.offset = ev->attr.probe.offset;
 210                 strncpy(attr->u.kretprobe.symbol_name,
 211                                 ev->attr.probe.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 212                 attr->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 213                 break;
 214         case LTTNG_EVENT_FUNCTION_ENTRY:
 215                 attr->instrumentation = LTTNG_KERNEL_FUNCTION;
 216                 strncpy(attr->u.ftrace.symbol_name,
 217                                 ev->attr.ftrace.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 218                 attr->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 219                 break;
 220         case LTTNG_EVENT_TRACEPOINT:
 221                 attr->instrumentation = LTTNG_KERNEL_TRACEPOINT;
 222                 break;
 223         case LTTNG_EVENT_SYSCALL:
 224                 attr->instrumentation = LTTNG_KERNEL_SYSCALL;
 225                 break;
 226         case LTTNG_EVENT_ALL:
 227                 attr->instrumentation = LTTNG_KERNEL_ALL;
 228                 break;
 229         default:
 230                 ERR("Unknown kernel instrumentation type (%d)", ev->type);
 231                 goto error;
 232         }
 233
 234         /* Copy event name */
 235         strncpy(attr->name, ev->name, LTTNG_KERNEL_SYM_NAME_LEN);
 236         attr->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 237
 238         /* Setting up a kernel event */
 239         lke->fd = -1;
 240         lke->event = attr;
 241         lke->enabled = 1;
 242         lke->ctx = NULL;
 243
 244         return lke;
 245
 246 error:
 247         free(lke);
 248         free(attr);
 249         return NULL;
 250 }
 251
 252 /*
 253  * Allocate and initialize a kernel metadata.
 254  *
 255  * Return pointer to structure or NULL.
 256  */
 257 struct ltt_kernel_metadata *trace_kernel_create_metadata(char *path)
 258 {
 259         struct ltt_kernel_metadata *lkm;
 260         struct lttng_channel *chan;
 261
 262         lkm = zmalloc(sizeof(struct ltt_kernel_metadata));
 263         chan = zmalloc(sizeof(struct lttng_channel));
 264         if (lkm == NULL || chan == NULL) {
 265                 PERROR("kernel metadata zmalloc");
 266                 goto error;
 267         }
 268
 269         /* Set default attributes */
 270         chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
 271         chan->attr.subbuf_size = DEFAULT_METADATA_SUBBUF_SIZE;
 272         chan->attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM;
 273         chan->attr.switch_timer_interval = DEFAULT_CHANNEL_SWITCH_TIMER;
 274         chan->attr.read_timer_interval = DEFAULT_CHANNEL_READ_TIMER;
 275         chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
 276
 277         /* Init metadata */
 278         lkm->fd = -1;
 279         lkm->conf = chan;
 280
 281         return lkm;
 282
 283 error:
 284         free(lkm);
 285         free(chan);
 286         return NULL;
 287 }
 288
 289 /*
 290  * Allocate and initialize a kernel stream. The stream is set to ACTIVE_FD by
 291  * default.
 292  *
 293  * Return pointer to structure or NULL.
 294  */
 295 struct ltt_kernel_stream *trace_kernel_create_stream(const char *name,
 296                 unsigned int count)
 297 {
 298         int ret;
 299         struct ltt_kernel_stream *lks;
 300
 301         lks = zmalloc(sizeof(struct ltt_kernel_stream));
 302         if (lks == NULL) {
 303                 PERROR("kernel stream zmalloc");
 304                 goto error;
 305         }
 306
 307         /* Set name */
 308         ret = snprintf(lks->name, sizeof(lks->name), "%s_%d", name, count);
 309         if (ret < 0) {
 310                 PERROR("snprintf stream name");
 311                 goto error;
 312         }
 313         lks->name[sizeof(lks->name) - 1] = '\0';
 314
 315         /* Init stream */
 316         lks->fd = -1;
 317         lks->state = 0;
 318
 319         return lks;
 320
 321 error:
 322         return NULL;
 323 }
 324
 325 /*
 326  * Cleanup kernel stream structure.
 327  */
 328 void trace_kernel_destroy_stream(struct ltt_kernel_stream *stream)
 329 {
 330         int ret;
 331
 332         DBG("[trace] Closing stream fd %d", stream->fd);
 333         /* Close kernel fd */
 334         if (stream->fd >= 0) {
 335                 ret = close(stream->fd);
 336                 if (ret) {
 337                         PERROR("close");
 338                 }
 339         }
 340         /* Remove from stream list */
 341         cds_list_del(&stream->list);
 342
 343         free(stream);
 344 }
 345
 346 /*
 347  * Cleanup kernel event structure.
 348  */
 349 void trace_kernel_destroy_event(struct ltt_kernel_event *event)
 350 {
 351         int ret;
 352
 353         if (event->fd >= 0) {
 354                 DBG("[trace] Closing event fd %d", event->fd);
 355                 /* Close kernel fd */
 356                 ret = close(event->fd);
 357                 if (ret) {
 358                         PERROR("close");
 359                 }
 360         } else {
 361                 DBG("[trace] Tearing down event (no associated fd)");
 362         }
 363
 364         /* Remove from event list */
 365         cds_list_del(&event->list);
 366
 367         free(event->event);
 368         free(event->ctx);
 369         free(event);
 370 }
 371
 372 /*
 373  * Cleanup kernel channel structure.
 374  */
 375 void trace_kernel_destroy_channel(struct ltt_kernel_channel *channel)
 376 {
 377         struct ltt_kernel_stream *stream, *stmp;
 378         struct ltt_kernel_event *event, *etmp;
 379         int ret;
 380
 381         DBG("[trace] Closing channel fd %d", channel->fd);
 382         /* Close kernel fd */
 383         if (channel->fd >= 0) {
 384                 ret = close(channel->fd);
 385                 if (ret) {
 386                         PERROR("close");
 387                 }
 388         }
 389
 390         /* For each stream in the channel list */
 391         cds_list_for_each_entry_safe(stream, stmp, &channel->stream_list.head, list) {
 392                 trace_kernel_destroy_stream(stream);
 393         }
 394
 395         /* For each event in the channel list */
 396         cds_list_for_each_entry_safe(event, etmp, &channel->events_list.head, list) {
 397                 trace_kernel_destroy_event(event);
 398         }
 399
 400         /* Remove from channel list */
 401         cds_list_del(&channel->list);
 402
 403         free(channel->channel);
 404         free(channel->ctx);
 405         free(channel);
 406 }
 407
 408 /*
 409  * Cleanup kernel metadata structure.
 410  */
 411 void trace_kernel_destroy_metadata(struct ltt_kernel_metadata *metadata)
 412 {
 413         int ret;
 414
 415         DBG("[trace] Closing metadata fd %d", metadata->fd);
 416         /* Close kernel fd */
 417         if (metadata->fd >= 0) {
 418                 ret = close(metadata->fd);
 419                 if (ret) {
 420                         PERROR("close");
 421                 }
 422         }
 423
 424         free(metadata->conf);
 425         free(metadata);
 426 }
 427
 428 /*
 429  * Cleanup kernel session structure
 430  */
 431 void trace_kernel_destroy_session(struct ltt_kernel_session *session)
 432 {
 433         struct ltt_kernel_channel *channel, *ctmp;
 434         int ret;
 435
 436         DBG("[trace] Closing session fd %d", session->fd);
 437         /* Close kernel fds */
 438         if (session->fd >= 0) {
 439                 ret = close(session->fd);
 440                 if (ret) {
 441                         PERROR("close");
 442                 }
 443         }
 444
 445         if (session->metadata_stream_fd >= 0) {
 446                 DBG("[trace] Closing metadata stream fd %d", session->metadata_stream_fd);
 447                 ret = close(session->metadata_stream_fd);
 448                 if (ret) {
 449                         PERROR("close");
 450                 }
 451         }
 452
 453         if (session->metadata != NULL) {
 454                 trace_kernel_destroy_metadata(session->metadata);
 455         }
 456
 457         cds_list_for_each_entry_safe(channel, ctmp, &session->channel_list.head, list) {
 458                 trace_kernel_destroy_channel(channel);
 459         }
 460
 461         /* Wipe consumer output object */
 462         consumer_destroy_output(session->consumer);
 463         consumer_destroy_output(session->tmp_consumer);
 464
 465         free(session->trace_path);
 466         free(session);
 467 }