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
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; only version 2
   7  * of the License.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  17  */
  18
  19 #define _GNU_SOURCE
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <unistd.h>
  24
  25 #include <common/common.h>
  26 #include <common/defaults.h>
  27
  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         /* Set session path */
 108         ret = asprintf(&lks->trace_path, "%s/kernel", path);
 109         if (ret < 0) {
 110                 PERROR("asprintf kernel traces path");
 111                 goto error;
 112         }
 113
 114         return lks;
 115
 116 error:
 117         return NULL;
 118 }
 119
 120 /*
 121  * Allocate and initialize a kernel channel data structure.
 122  *
 123  * Return pointer to structure or NULL.
 124  */
 125 struct ltt_kernel_channel *trace_kernel_create_channel(struct lttng_channel *chan, char *path)
 126 {
 127         int ret;
 128         struct ltt_kernel_channel *lkc;
 129
 130         lkc = zmalloc(sizeof(struct ltt_kernel_channel));
 131         if (lkc == NULL) {
 132                 PERROR("ltt_kernel_channel zmalloc");
 133                 goto error;
 134         }
 135
 136         lkc->channel = zmalloc(sizeof(struct lttng_channel));
 137         if (lkc->channel == NULL) {
 138                 PERROR("lttng_channel zmalloc");
 139                 goto error;
 140         }
 141         memcpy(lkc->channel, chan, sizeof(struct lttng_channel));
 142
 143         lkc->fd = -1;
 144         lkc->stream_count = 0;
 145         lkc->event_count = 0;
 146         lkc->enabled = 1;
 147         lkc->ctx = NULL;
 148         /* Init linked list */
 149         CDS_INIT_LIST_HEAD(&lkc->events_list.head);
 150         CDS_INIT_LIST_HEAD(&lkc->stream_list.head);
 151         /* Set default trace output path */
 152         ret = asprintf(&lkc->pathname, "%s", path);
 153         if (ret < 0) {
 154                 PERROR("asprintf kernel create channel");
 155                 goto error;
 156         }
 157
 158         return lkc;
 159
 160 error:
 161         return NULL;
 162 }
 163
 164 /*
 165  * Allocate and initialize a kernel event. Set name and event type.
 166  *
 167  * Return pointer to structure or NULL.
 168  */
 169 struct ltt_kernel_event *trace_kernel_create_event(struct lttng_event *ev)
 170 {
 171         struct ltt_kernel_event *lke;
 172         struct lttng_kernel_event *attr;
 173
 174         lke = zmalloc(sizeof(struct ltt_kernel_event));
 175         attr = zmalloc(sizeof(struct lttng_kernel_event));
 176         if (lke == NULL || attr == NULL) {
 177                 PERROR("kernel event zmalloc");
 178                 goto error;
 179         }
 180
 181         switch (ev->type) {
 182         case LTTNG_EVENT_PROBE:
 183                 attr->instrumentation = LTTNG_KERNEL_KPROBE;
 184                 attr->u.kprobe.addr = ev->attr.probe.addr;
 185                 attr->u.kprobe.offset = ev->attr.probe.offset;
 186                 strncpy(attr->u.kprobe.symbol_name,
 187                                 ev->attr.probe.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 188                 attr->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 189                 break;
 190         case LTTNG_EVENT_FUNCTION:
 191                 attr->instrumentation = LTTNG_KERNEL_KRETPROBE;
 192                 attr->u.kretprobe.addr = ev->attr.probe.addr;
 193                 attr->u.kretprobe.offset = ev->attr.probe.offset;
 194                 attr->u.kretprobe.offset = ev->attr.probe.offset;
 195                 strncpy(attr->u.kretprobe.symbol_name,
 196                                 ev->attr.probe.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 197                 attr->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 198                 break;
 199         case LTTNG_EVENT_FUNCTION_ENTRY:
 200                 attr->instrumentation = LTTNG_KERNEL_FUNCTION;
 201                 strncpy(attr->u.ftrace.symbol_name,
 202                                 ev->attr.ftrace.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 203                 attr->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 204                 break;
 205         case LTTNG_EVENT_TRACEPOINT:
 206                 attr->instrumentation = LTTNG_KERNEL_TRACEPOINT;
 207                 break;
 208         case LTTNG_EVENT_SYSCALL:
 209                 attr->instrumentation = LTTNG_KERNEL_SYSCALL;
 210                 break;
 211         case LTTNG_EVENT_ALL:
 212                 attr->instrumentation = LTTNG_KERNEL_ALL;
 213                 break;
 214         default:
 215                 ERR("Unknown kernel instrumentation type (%d)", ev->type);
 216                 goto error;
 217         }
 218
 219         /* Copy event name */
 220         strncpy(attr->name, ev->name, LTTNG_KERNEL_SYM_NAME_LEN);
 221         attr->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 222
 223         /* Setting up a kernel event */
 224         lke->fd = -1;
 225         lke->event = attr;
 226         lke->enabled = 1;
 227         lke->ctx = NULL;
 228
 229         return lke;
 230
 231 error:
 232         return NULL;
 233 }
 234
 235 /*
 236  * Allocate and initialize a kernel metadata.
 237  *
 238  * Return pointer to structure or NULL.
 239  */
 240 struct ltt_kernel_metadata *trace_kernel_create_metadata(char *path)
 241 {
 242         int ret;
 243         struct ltt_kernel_metadata *lkm;
 244         struct lttng_channel *chan;
 245
 246         lkm = zmalloc(sizeof(struct ltt_kernel_metadata));
 247         chan = zmalloc(sizeof(struct lttng_channel));
 248         if (lkm == NULL || chan == NULL) {
 249                 PERROR("kernel metadata zmalloc");
 250                 goto error;
 251         }
 252
 253         /* Set default attributes */
 254         chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
 255         chan->attr.subbuf_size = DEFAULT_METADATA_SUBBUF_SIZE;
 256         chan->attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM;
 257         chan->attr.switch_timer_interval = DEFAULT_CHANNEL_SWITCH_TIMER;
 258         chan->attr.read_timer_interval = DEFAULT_CHANNEL_READ_TIMER;
 259         chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
 260
 261         /* Init metadata */
 262         lkm->fd = -1;
 263         lkm->conf = chan;
 264         /* Set default metadata path */
 265         ret = asprintf(&lkm->pathname, "%s/metadata", path);
 266         if (ret < 0) {
 267                 PERROR("asprintf kernel metadata");
 268                 goto error;
 269         }
 270
 271         return lkm;
 272
 273 error:
 274         return NULL;
 275 }
 276
 277 /*
 278  * Allocate and initialize a kernel stream. The stream is set to ACTIVE_FD by
 279  * default.
 280  *
 281  * Return pointer to structure or NULL.
 282  */
 283 struct ltt_kernel_stream *trace_kernel_create_stream(void)
 284 {
 285         struct ltt_kernel_stream *lks;
 286
 287         lks = zmalloc(sizeof(struct ltt_kernel_stream));
 288         if (lks == NULL) {
 289                 PERROR("kernel stream zmalloc");
 290                 goto error;
 291         }
 292
 293         /* Init stream */
 294         lks->fd = -1;
 295         lks->pathname = NULL;
 296         lks->state = 0;
 297
 298         return lks;
 299
 300 error:
 301         return NULL;
 302 }
 303
 304 /*
 305  * Cleanup kernel stream structure.
 306  */
 307 void trace_kernel_destroy_stream(struct ltt_kernel_stream *stream)
 308 {
 309         int ret;
 310
 311         DBG("[trace] Closing stream fd %d", stream->fd);
 312         /* Close kernel fd */
 313         if (stream->fd >= 0) {
 314                 ret = close(stream->fd);
 315                 if (ret) {
 316                         PERROR("close");
 317                 }
 318         }
 319         /* Remove from stream list */
 320         cds_list_del(&stream->list);
 321
 322         free(stream->pathname);
 323         free(stream);
 324 }
 325
 326 /*
 327  * Cleanup kernel event structure.
 328  */
 329 void trace_kernel_destroy_event(struct ltt_kernel_event *event)
 330 {
 331         int ret;
 332
 333         if (event->fd >= 0) {
 334                 DBG("[trace] Closing event fd %d", event->fd);
 335                 /* Close kernel fd */
 336                 ret = close(event->fd);
 337                 if (ret) {
 338                         PERROR("close");
 339                 }
 340         } else {
 341                 DBG("[trace] Tearing down event (no associated fd)");
 342         }
 343
 344         /* Remove from event list */
 345         cds_list_del(&event->list);
 346
 347         free(event->event);
 348         free(event->ctx);
 349         free(event);
 350 }
 351
 352 /*
 353  * Cleanup kernel channel structure.
 354  */
 355 void trace_kernel_destroy_channel(struct ltt_kernel_channel *channel)
 356 {
 357         struct ltt_kernel_stream *stream, *stmp;
 358         struct ltt_kernel_event *event, *etmp;
 359         int ret;
 360
 361         DBG("[trace] Closing channel fd %d", channel->fd);
 362         /* Close kernel fd */
 363         if (channel->fd >= 0) {
 364                 ret = close(channel->fd);
 365                 if (ret) {
 366                         PERROR("close");
 367                 }
 368         }
 369
 370         /* For each stream in the channel list */
 371         cds_list_for_each_entry_safe(stream, stmp, &channel->stream_list.head, list) {
 372                 trace_kernel_destroy_stream(stream);
 373         }
 374
 375         /* For each event in the channel list */
 376         cds_list_for_each_entry_safe(event, etmp, &channel->events_list.head, list) {
 377                 trace_kernel_destroy_event(event);
 378         }
 379
 380         /* Remove from channel list */
 381         cds_list_del(&channel->list);
 382
 383         free(channel->pathname);
 384         free(channel->channel);
 385         free(channel->ctx);
 386         free(channel);
 387 }
 388
 389 /*
 390  * Cleanup kernel metadata structure.
 391  */
 392 void trace_kernel_destroy_metadata(struct ltt_kernel_metadata *metadata)
 393 {
 394         int ret;
 395
 396         DBG("[trace] Closing metadata fd %d", metadata->fd);
 397         /* Close kernel fd */
 398         if (metadata->fd >= 0) {
 399                 ret = close(metadata->fd);
 400                 if (ret) {
 401                         PERROR("close");
 402                 }
 403         }
 404
 405         free(metadata->conf);
 406         free(metadata->pathname);
 407         free(metadata);
 408 }
 409
 410 /*
 411  * Cleanup kernel session structure
 412  */
 413 void trace_kernel_destroy_session(struct ltt_kernel_session *session)
 414 {
 415         struct ltt_kernel_channel *channel, *ctmp;
 416         int ret;
 417
 418         DBG("[trace] Closing session fd %d", session->fd);
 419         /* Close kernel fds */
 420         if (session->fd >= 0) {
 421                 ret = close(session->fd);
 422                 if (ret) {
 423                         PERROR("close");
 424                 }
 425         }
 426
 427         if (session->metadata_stream_fd >= 0) {
 428                 DBG("[trace] Closing metadata stream fd %d", session->metadata_stream_fd);
 429                 ret = close(session->metadata_stream_fd);
 430                 if (ret) {
 431                         PERROR("close");
 432                 }
 433         }
 434
 435         if (session->metadata != NULL) {
 436                 trace_kernel_destroy_metadata(session->metadata);
 437         }
 438
 439         cds_list_for_each_entry_safe(channel, ctmp, &session->channel_list.head, list) {
 440                 trace_kernel_destroy_channel(channel);
 441         }
 442
 443         free(session->trace_path);
 444         free(session);
 445 }