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/lttngerr.h>
  26 #include <common/common.h>
  27 #include <common/defaults.h>
  28
  29 #include "trace-kernel.h"
  30
  31 /*
  32  * Find the channel name for the given kernel session.
  33  */
  34 struct ltt_kernel_channel *trace_kernel_get_channel_by_name(
  35                 char *name, struct ltt_kernel_session *session)
  36 {
  37         struct ltt_kernel_channel *chan;
  38
  39         if (session == NULL) {
  40                 ERR("Undefine session");
  41                 goto error;
  42         }
  43
  44         DBG("Trying to find channel %s", name);
  45
  46         cds_list_for_each_entry(chan, &session->channel_list.head, list) {
  47                 if (strcmp(name, chan->channel->name) == 0) {
  48                         DBG("Found channel by name %s", name);
  49                         return chan;
  50                 }
  51         }
  52
  53 error:
  54         return NULL;
  55 }
  56
  57 /*
  58  * Find the event name for the given channel.
  59  */
  60 struct ltt_kernel_event *trace_kernel_get_event_by_name(
  61                 char *name, struct ltt_kernel_channel *channel)
  62 {
  63         struct ltt_kernel_event *ev;
  64
  65         if (channel == NULL) {
  66                 ERR("Undefine channel");
  67                 goto error;
  68         }
  69
  70         cds_list_for_each_entry(ev, &channel->events_list.head, list) {
  71                 if (strcmp(name, ev->event->name) == 0) {
  72                         DBG("Found event by name %s for channel %s", name,
  73                                         channel->channel->name);
  74                         return ev;
  75                 }
  76         }
  77
  78 error:
  79         return NULL;
  80 }
  81
  82 /*
  83  * Allocate and initialize a kernel session data structure.
  84  *
  85  * Return pointer to structure or NULL.
  86  */
  87 struct ltt_kernel_session *trace_kernel_create_session(char *path)
  88 {
  89         int ret;
  90         struct ltt_kernel_session *lks;
  91
  92         /* Allocate a new ltt kernel session */
  93         lks = zmalloc(sizeof(struct ltt_kernel_session));
  94         if (lks == NULL) {
  95                 perror("create kernel session zmalloc");
  96                 goto error;
  97         }
  98
  99         /* Init data structure */
 100         lks->fd = 0;
 101         lks->metadata_stream_fd = 0;
 102         lks->channel_count = 0;
 103         lks->stream_count_global = 0;
 104         lks->metadata = NULL;
 105         lks->consumer_fd = 0;
 106         CDS_INIT_LIST_HEAD(&lks->channel_list.head);
 107
 108         /* Set session path */
 109         ret = asprintf(&lks->trace_path, "%s/kernel", path);
 110         if (ret < 0) {
 111                 perror("asprintf kernel traces path");
 112                 goto error;
 113         }
 114
 115         return lks;
 116
 117 error:
 118         return NULL;
 119 }
 120
 121 /*
 122  * Allocate and initialize a kernel channel data structure.
 123  *
 124  * Return pointer to structure or NULL.
 125  */
 126 struct ltt_kernel_channel *trace_kernel_create_channel(struct lttng_channel *chan, char *path)
 127 {
 128         int ret;
 129         struct ltt_kernel_channel *lkc;
 130
 131         lkc = zmalloc(sizeof(struct ltt_kernel_channel));
 132         if (lkc == NULL) {
 133                 perror("ltt_kernel_channel zmalloc");
 134                 goto error;
 135         }
 136
 137         lkc->channel = zmalloc(sizeof(struct lttng_channel));
 138         if (lkc->channel == NULL) {
 139                 perror("lttng_channel zmalloc");
 140                 goto error;
 141         }
 142         memcpy(lkc->channel, chan, sizeof(struct lttng_channel));
 143
 144         lkc->fd = 0;
 145         lkc->stream_count = 0;
 146         lkc->event_count = 0;
 147         lkc->enabled = 1;
 148         lkc->ctx = NULL;
 149         /* Init linked list */
 150         CDS_INIT_LIST_HEAD(&lkc->events_list.head);
 151         CDS_INIT_LIST_HEAD(&lkc->stream_list.head);
 152         /* Set default trace output path */
 153         ret = asprintf(&lkc->pathname, "%s", path);
 154         if (ret < 0) {
 155                 perror("asprintf kernel create channel");
 156                 goto error;
 157         }
 158
 159         return lkc;
 160
 161 error:
 162         return NULL;
 163 }
 164
 165 /*
 166  * Allocate and initialize a kernel event. Set name and event type.
 167  *
 168  * Return pointer to structure or NULL.
 169  */
 170 struct ltt_kernel_event *trace_kernel_create_event(struct lttng_event *ev)
 171 {
 172         struct ltt_kernel_event *lke;
 173         struct lttng_kernel_event *attr;
 174
 175         lke = zmalloc(sizeof(struct ltt_kernel_event));
 176         attr = zmalloc(sizeof(struct lttng_kernel_event));
 177         if (lke == NULL || attr == NULL) {
 178                 perror("kernel event zmalloc");
 179                 goto error;
 180         }
 181
 182         switch (ev->type) {
 183         case LTTNG_EVENT_PROBE:
 184                 attr->instrumentation = LTTNG_KERNEL_KPROBE;
 185                 attr->u.kprobe.addr = ev->attr.probe.addr;
 186                 attr->u.kprobe.offset = ev->attr.probe.offset;
 187                 strncpy(attr->u.kprobe.symbol_name,
 188                                 ev->attr.probe.symbol_name, LTTNG_SYM_NAME_LEN);
 189                 attr->u.kprobe.symbol_name[LTTNG_SYM_NAME_LEN - 1] = '\0';
 190                 break;
 191         case LTTNG_EVENT_FUNCTION:
 192                 attr->instrumentation = LTTNG_KERNEL_KRETPROBE;
 193                 attr->u.kretprobe.addr = ev->attr.probe.addr;
 194                 attr->u.kretprobe.offset = ev->attr.probe.offset;
 195                 attr->u.kretprobe.offset = ev->attr.probe.offset;
 196                 strncpy(attr->u.kretprobe.symbol_name,
 197                                 ev->attr.probe.symbol_name, LTTNG_SYM_NAME_LEN);
 198                 attr->u.kretprobe.symbol_name[LTTNG_SYM_NAME_LEN - 1] = '\0';
 199                 break;
 200         case LTTNG_EVENT_FUNCTION_ENTRY:
 201                 attr->instrumentation = LTTNG_KERNEL_FUNCTION;
 202                 strncpy(attr->u.ftrace.symbol_name,
 203                                 ev->attr.ftrace.symbol_name, LTTNG_SYM_NAME_LEN);
 204                 attr->u.ftrace.symbol_name[LTTNG_SYM_NAME_LEN - 1] = '\0';
 205                 break;
 206         case LTTNG_EVENT_TRACEPOINT:
 207                 attr->instrumentation = LTTNG_KERNEL_TRACEPOINT;
 208                 break;
 209         case LTTNG_EVENT_SYSCALL:
 210                 attr->instrumentation = LTTNG_KERNEL_SYSCALL;
 211                 break;
 212         case LTTNG_EVENT_ALL:
 213                 attr->instrumentation = LTTNG_KERNEL_ALL;
 214                 break;
 215         default:
 216                 ERR("Unknown kernel instrumentation type (%d)", ev->type);
 217                 goto error;
 218         }
 219
 220         /* Copy event name */
 221         strncpy(attr->name, ev->name, LTTNG_SYM_NAME_LEN);
 222         attr->name[LTTNG_SYM_NAME_LEN - 1] = '\0';
 223
 224         /* Setting up a kernel event */
 225         lke->fd = 0;
 226         lke->event = attr;
 227         lke->enabled = 1;
 228         lke->ctx = NULL;
 229
 230         return lke;
 231
 232 error:
 233         return NULL;
 234 }
 235
 236 /*
 237  * Allocate and initialize a kernel metadata.
 238  *
 239  * Return pointer to structure or NULL.
 240  */
 241 struct ltt_kernel_metadata *trace_kernel_create_metadata(char *path)
 242 {
 243         int ret;
 244         struct ltt_kernel_metadata *lkm;
 245         struct lttng_channel *chan;
 246
 247         lkm = zmalloc(sizeof(struct ltt_kernel_metadata));
 248         chan = zmalloc(sizeof(struct lttng_channel));
 249         if (lkm == NULL || chan == NULL) {
 250                 perror("kernel metadata zmalloc");
 251                 goto error;
 252         }
 253
 254         /* Set default attributes */
 255         chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
 256         chan->attr.subbuf_size = DEFAULT_METADATA_SUBBUF_SIZE;
 257         chan->attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM;
 258         chan->attr.switch_timer_interval = DEFAULT_CHANNEL_SWITCH_TIMER;
 259         chan->attr.read_timer_interval = DEFAULT_CHANNEL_READ_TIMER;
 260         chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
 261
 262         /* Init metadata */
 263         lkm->fd = 0;
 264         lkm->conf = chan;
 265         /* Set default metadata path */
 266         ret = asprintf(&lkm->pathname, "%s/metadata", path);
 267         if (ret < 0) {
 268                 perror("asprintf kernel metadata");
 269                 goto error;
 270         }
 271
 272         return lkm;
 273
 274 error:
 275         return NULL;
 276 }
 277
 278 /*
 279  * Allocate and initialize a kernel stream. The stream is set to ACTIVE_FD by
 280  * default.
 281  *
 282  * Return pointer to structure or NULL.
 283  */
 284 struct ltt_kernel_stream *trace_kernel_create_stream(void)
 285 {
 286         struct ltt_kernel_stream *lks;
 287
 288         lks = zmalloc(sizeof(struct ltt_kernel_stream));
 289         if (lks == NULL) {
 290                 perror("kernel stream zmalloc");
 291                 goto error;
 292         }
 293
 294         /* Init stream */
 295         lks->fd = 0;
 296         lks->pathname = NULL;
 297         lks->state = 0;
 298
 299         return lks;
 300
 301 error:
 302         return NULL;
 303 }
 304
 305 /*
 306  * Cleanup kernel stream structure.
 307  */
 308 void trace_kernel_destroy_stream(struct ltt_kernel_stream *stream)
 309 {
 310         DBG("[trace] Closing stream fd %d", stream->fd);
 311         /* Close kernel fd */
 312         close(stream->fd);
 313         /* Remove from stream list */
 314         cds_list_del(&stream->list);
 315
 316         free(stream->pathname);
 317         free(stream);
 318 }
 319
 320 /*
 321  * Cleanup kernel event structure.
 322  */
 323 void trace_kernel_destroy_event(struct ltt_kernel_event *event)
 324 {
 325         DBG("[trace] Closing event fd %d", event->fd);
 326         /* Close kernel fd */
 327         close(event->fd);
 328
 329         /* Remove from event list */
 330         cds_list_del(&event->list);
 331
 332         free(event->event);
 333         free(event->ctx);
 334         free(event);
 335 }
 336
 337 /*
 338  * Cleanup kernel channel structure.
 339  */
 340 void trace_kernel_destroy_channel(struct ltt_kernel_channel *channel)
 341 {
 342         struct ltt_kernel_stream *stream, *stmp;
 343         struct ltt_kernel_event *event, *etmp;
 344
 345         DBG("[trace] Closing channel fd %d", channel->fd);
 346         /* Close kernel fd */
 347         close(channel->fd);
 348
 349         /* For each stream in the channel list */
 350         cds_list_for_each_entry_safe(stream, stmp, &channel->stream_list.head, list) {
 351                 trace_kernel_destroy_stream(stream);
 352         }
 353
 354         /* For each event in the channel list */
 355         cds_list_for_each_entry_safe(event, etmp, &channel->events_list.head, list) {
 356                 trace_kernel_destroy_event(event);
 357         }
 358
 359         /* Remove from channel list */
 360         cds_list_del(&channel->list);
 361
 362         free(channel->pathname);
 363         free(channel->channel);
 364         free(channel->ctx);
 365         free(channel);
 366 }
 367
 368 /*
 369  * Cleanup kernel metadata structure.
 370  */
 371 void trace_kernel_destroy_metadata(struct ltt_kernel_metadata *metadata)
 372 {
 373         DBG("[trace] Closing metadata fd %d", metadata->fd);
 374         /* Close kernel fd */
 375         close(metadata->fd);
 376
 377         free(metadata->conf);
 378         free(metadata->pathname);
 379         free(metadata);
 380 }
 381
 382 /*
 383  * Cleanup kernel session structure
 384  */
 385 void trace_kernel_destroy_session(struct ltt_kernel_session *session)
 386 {
 387         struct ltt_kernel_channel *channel, *ctmp;
 388
 389         DBG("[trace] Closing session fd %d", session->fd);
 390         /* Close kernel fds */
 391         close(session->fd);
 392
 393         if (session->metadata_stream_fd != 0) {
 394                 DBG("[trace] Closing metadata stream fd %d", session->metadata_stream_fd);
 395                 close(session->metadata_stream_fd);
 396         }
 397
 398         if (session->metadata != NULL) {
 399                 trace_kernel_destroy_metadata(session->metadata);
 400         }
 401
 402         cds_list_for_each_entry_safe(channel, ctmp, &session->channel_list.head, list) {
 403                 trace_kernel_destroy_channel(channel);
 404         }
 405
 406         free(session->trace_path);
 407         free(session);
 408 }