lttng-abi.c

   1 /*
   2  * lttng-abi.c
   3  *
   4  * LTTng ABI
   5  *
   6  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; only
  11  * version 2.1 of the License.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  *
  22  *
  23  * Mimic system calls for:
  24  * - session creation, returns a file descriptor or failure.
  25  *   - channel creation, returns a file descriptor or failure.
  26  *     - Operates on a session file descriptor
  27  *     - Takes all channel options as parameters.
  28  *   - stream get, returns a file descriptor or failure.
  29  *     - Operates on a channel file descriptor.
  30  *   - stream notifier get, returns a file descriptor or failure.
  31  *     - Operates on a channel file descriptor.
  32  *   - event creation, returns a file descriptor or failure.
  33  *     - Operates on a channel file descriptor
  34  *     - Takes an event name as parameter
  35  *     - Takes an instrumentation source as parameter
  36  *       - e.g. tracepoints, dynamic_probes...
  37  *     - Takes instrumentation source specific arguments.
  38  */
  39
  40 #include <linux/module.h>
  41 #include <linux/proc_fs.h>
  42 #include <linux/anon_inodes.h>
  43 #include <linux/file.h>
  44 #include <linux/uaccess.h>
  45 #include <linux/slab.h>
  46 #include "wrapper/vmalloc.h"    /* for wrapper_vmalloc_sync_all() */
  47 #include "wrapper/ringbuffer/vfs.h"
  48 #include "wrapper/ringbuffer/backend.h"
  49 #include "wrapper/ringbuffer/frontend.h"
  50 #include "wrapper/poll.h"
  51 #include "lttng-abi.h"
  52 #include "lttng-abi-old.h"
  53 #include "lttng-events.h"
  54 #include "lttng-tracer.h"
  55
  56 /*
  57  * This is LTTng's own personal way to create a system call as an external
  58  * module. We use ioctl() on /proc/lttng.
  59  */
  60
  61 static struct proc_dir_entry *lttng_proc_dentry;
  62 static const struct file_operations lttng_fops;
  63 static const struct file_operations lttng_session_fops;
  64 static const struct file_operations lttng_channel_fops;
  65 static const struct file_operations lttng_metadata_fops;
  66 static const struct file_operations lttng_event_fops;
  67
  68 /*
  69  * Teardown management: opened file descriptors keep a refcount on the module,
  70  * so it can only exit when all file descriptors are closed.
  71  */
  72
  73 static
  74 int lttng_abi_create_session(void)
  75 {
  76         struct lttng_session *session;
  77         struct file *session_file;
  78         int session_fd, ret;
  79
  80         session = lttng_session_create();
  81         if (!session)
  82                 return -ENOMEM;
  83         session_fd = get_unused_fd();
  84         if (session_fd < 0) {
  85                 ret = session_fd;
  86                 goto fd_error;
  87         }
  88         session_file = anon_inode_getfile("[lttng_session]",
  89                                           &lttng_session_fops,
  90                                           session, O_RDWR);
  91         if (IS_ERR(session_file)) {
  92                 ret = PTR_ERR(session_file);
  93                 goto file_error;
  94         }
  95         session->file = session_file;
  96         fd_install(session_fd, session_file);
  97         return session_fd;
  98
  99 file_error:
 100         put_unused_fd(session_fd);
 101 fd_error:
 102         lttng_session_destroy(session);
 103         return ret;
 104 }
 105
 106 static
 107 int lttng_abi_tracepoint_list(void)
 108 {
 109         struct file *tracepoint_list_file;
 110         int file_fd, ret;
 111
 112         file_fd = get_unused_fd();
 113         if (file_fd < 0) {
 114                 ret = file_fd;
 115                 goto fd_error;
 116         }
 117
 118         tracepoint_list_file = anon_inode_getfile("[lttng_session]",
 119                                           &lttng_tracepoint_list_fops,
 120                                           NULL, O_RDWR);
 121         if (IS_ERR(tracepoint_list_file)) {
 122                 ret = PTR_ERR(tracepoint_list_file);
 123                 goto file_error;
 124         }
 125         ret = lttng_tracepoint_list_fops.open(NULL, tracepoint_list_file);
 126         if (ret < 0)
 127                 goto open_error;
 128         fd_install(file_fd, tracepoint_list_file);
 129         if (file_fd < 0) {
 130                 ret = file_fd;
 131                 goto fd_error;
 132         }
 133         return file_fd;
 134
 135 open_error:
 136         fput(tracepoint_list_file);
 137 file_error:
 138         put_unused_fd(file_fd);
 139 fd_error:
 140         return ret;
 141 }
 142
 143 static
 144 void lttng_abi_tracer_version(struct lttng_kernel_tracer_version *v)
 145 {
 146         v->major = LTTNG_MODULES_MAJOR_VERSION;
 147         v->minor = LTTNG_MODULES_MINOR_VERSION;
 148         v->patchlevel = LTTNG_MODULES_PATCHLEVEL_VERSION;
 149 }
 150
 151 static
 152 long lttng_abi_add_context(struct file *file,
 153         struct lttng_kernel_context *context_param,
 154         struct lttng_ctx **ctx, struct lttng_session *session)
 155 {
 156
 157         if (session->been_active)
 158                 return -EPERM;
 159
 160         switch (context_param->ctx) {
 161         case LTTNG_KERNEL_CONTEXT_PID:
 162                 return lttng_add_pid_to_ctx(ctx);
 163         case LTTNG_KERNEL_CONTEXT_PRIO:
 164                 return lttng_add_prio_to_ctx(ctx);
 165         case LTTNG_KERNEL_CONTEXT_NICE:
 166                 return lttng_add_nice_to_ctx(ctx);
 167         case LTTNG_KERNEL_CONTEXT_VPID:
 168                 return lttng_add_vpid_to_ctx(ctx);
 169         case LTTNG_KERNEL_CONTEXT_TID:
 170                 return lttng_add_tid_to_ctx(ctx);
 171         case LTTNG_KERNEL_CONTEXT_VTID:
 172                 return lttng_add_vtid_to_ctx(ctx);
 173         case LTTNG_KERNEL_CONTEXT_PPID:
 174                 return lttng_add_ppid_to_ctx(ctx);
 175         case LTTNG_KERNEL_CONTEXT_VPPID:
 176                 return lttng_add_vppid_to_ctx(ctx);
 177         case LTTNG_KERNEL_CONTEXT_PERF_COUNTER:
 178                 context_param->u.perf_counter.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 179                 return lttng_add_perf_counter_to_ctx(context_param->u.perf_counter.type,
 180                                 context_param->u.perf_counter.config,
 181                                 context_param->u.perf_counter.name,
 182                                 ctx);
 183         case LTTNG_KERNEL_CONTEXT_PROCNAME:
 184                 return lttng_add_procname_to_ctx(ctx);
 185         case LTTNG_KERNEL_CONTEXT_HOSTNAME:
 186                 return lttng_add_hostname_to_ctx(ctx);
 187         default:
 188                 return -EINVAL;
 189         }
 190 }
 191
 192 /**
 193  *      lttng_ioctl - lttng syscall through ioctl
 194  *
 195  *      @file: the file
 196  *      @cmd: the command
 197  *      @arg: command arg
 198  *
 199  *      This ioctl implements lttng commands:
 200  *      LTTNG_KERNEL_SESSION
 201  *              Returns a LTTng trace session file descriptor
 202  *      LTTNG_KERNEL_TRACER_VERSION
 203  *              Returns the LTTng kernel tracer version
 204  *      LTTNG_KERNEL_TRACEPOINT_LIST
 205  *              Returns a file descriptor listing available tracepoints
 206  *      LTTNG_KERNEL_WAIT_QUIESCENT
 207  *              Returns after all previously running probes have completed
 208  *
 209  * The returned session will be deleted when its file descriptor is closed.
 210  */
 211 static
 212 long lttng_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 213 {
 214         switch (cmd) {
 215         case LTTNG_KERNEL_OLD_SESSION:
 216         case LTTNG_KERNEL_SESSION:
 217                 return lttng_abi_create_session();
 218         case LTTNG_KERNEL_OLD_TRACER_VERSION:
 219         {
 220                 struct lttng_kernel_tracer_version v;
 221                 struct lttng_kernel_old_tracer_version oldv;
 222                 struct lttng_kernel_old_tracer_version *uversion =
 223                         (struct lttng_kernel_old_tracer_version __user *) arg;
 224
 225                 lttng_abi_tracer_version(&v);
 226                 oldv.major = v.major;
 227                 oldv.minor = v.minor;
 228                 oldv.patchlevel = v.patchlevel;
 229
 230                 if (copy_to_user(uversion, &oldv, sizeof(oldv)))
 231                         return -EFAULT;
 232                 return 0;
 233         }
 234         case LTTNG_KERNEL_TRACER_VERSION:
 235         {
 236                 struct lttng_kernel_tracer_version version;
 237                 struct lttng_kernel_tracer_version *uversion =
 238                         (struct lttng_kernel_tracer_version __user *) arg;
 239
 240                 lttng_abi_tracer_version(&version);
 241
 242                 if (copy_to_user(uversion, &version, sizeof(version)))
 243                         return -EFAULT;
 244                 return 0;
 245         }
 246         case LTTNG_KERNEL_OLD_TRACEPOINT_LIST:
 247         case LTTNG_KERNEL_TRACEPOINT_LIST:
 248                 return lttng_abi_tracepoint_list();
 249         case LTTNG_KERNEL_OLD_WAIT_QUIESCENT:
 250         case LTTNG_KERNEL_WAIT_QUIESCENT:
 251                 synchronize_trace();
 252                 return 0;
 253         case LTTNG_KERNEL_OLD_CALIBRATE:
 254         {
 255                 struct lttng_kernel_old_calibrate __user *ucalibrate =
 256                         (struct lttng_kernel_old_calibrate __user *) arg;
 257                 struct lttng_kernel_old_calibrate old_calibrate;
 258                 struct lttng_kernel_calibrate calibrate;
 259                 int ret;
 260
 261                 if (copy_from_user(&old_calibrate, ucalibrate, sizeof(old_calibrate)))
 262                         return -EFAULT;
 263                 calibrate.type = old_calibrate.type;
 264                 ret = lttng_calibrate(&calibrate);
 265                 if (copy_to_user(ucalibrate, &old_calibrate, sizeof(old_calibrate)))
 266                         return -EFAULT;
 267                 return ret;
 268         }
 269         case LTTNG_KERNEL_CALIBRATE:
 270         {
 271                 struct lttng_kernel_calibrate __user *ucalibrate =
 272                         (struct lttng_kernel_calibrate __user *) arg;
 273                 struct lttng_kernel_calibrate calibrate;
 274                 int ret;
 275
 276                 if (copy_from_user(&calibrate, ucalibrate, sizeof(calibrate)))
 277                         return -EFAULT;
 278                 ret = lttng_calibrate(&calibrate);
 279                 if (copy_to_user(ucalibrate, &calibrate, sizeof(calibrate)))
 280                         return -EFAULT;
 281                 return ret;
 282         }
 283         default:
 284                 return -ENOIOCTLCMD;
 285         }
 286 }
 287
 288 static const struct file_operations lttng_fops = {
 289         .owner = THIS_MODULE,
 290         .unlocked_ioctl = lttng_ioctl,
 291 #ifdef CONFIG_COMPAT
 292         .compat_ioctl = lttng_ioctl,
 293 #endif
 294 };
 295
 296 static
 297 int lttng_abi_create_channel(struct file *session_file,
 298                              struct lttng_kernel_channel *chan_param,
 299                              enum channel_type channel_type)
 300 {
 301         struct lttng_session *session = session_file->private_data;
 302         const struct file_operations *fops = NULL;
 303         const char *transport_name;
 304         struct lttng_channel *chan;
 305         struct file *chan_file;
 306         int chan_fd;
 307         int ret = 0;
 308
 309         chan_fd = get_unused_fd();
 310         if (chan_fd < 0) {
 311                 ret = chan_fd;
 312                 goto fd_error;
 313         }
 314         switch (channel_type) {
 315         case PER_CPU_CHANNEL:
 316                 fops = &lttng_channel_fops;
 317                 break;
 318         case METADATA_CHANNEL:
 319                 fops = &lttng_metadata_fops;
 320                 break;
 321         }
 322
 323         chan_file = anon_inode_getfile("[lttng_channel]",
 324                                        fops,
 325                                        NULL, O_RDWR);
 326         if (IS_ERR(chan_file)) {
 327                 ret = PTR_ERR(chan_file);
 328                 goto file_error;
 329         }
 330         switch (channel_type) {
 331         case PER_CPU_CHANNEL:
 332                 if (chan_param->output == LTTNG_KERNEL_SPLICE) {
 333                         transport_name = chan_param->overwrite ?
 334                                 "relay-overwrite" : "relay-discard";
 335                 } else if (chan_param->output == LTTNG_KERNEL_MMAP) {
 336                         transport_name = chan_param->overwrite ?
 337                                 "relay-overwrite-mmap" : "relay-discard-mmap";
 338                 } else {
 339                         return -EINVAL;
 340                 }
 341                 break;
 342         case METADATA_CHANNEL:
 343                 if (chan_param->output == LTTNG_KERNEL_SPLICE)
 344                         transport_name = "relay-metadata";
 345                 else if (chan_param->output == LTTNG_KERNEL_MMAP)
 346                         transport_name = "relay-metadata-mmap";
 347                 else
 348                         return -EINVAL;
 349                 break;
 350         default:
 351                 transport_name = "<unknown>";
 352                 break;
 353         }
 354         /*
 355          * We tolerate no failure path after channel creation. It will stay
 356          * invariant for the rest of the session.
 357          */
 358         chan = lttng_channel_create(session, transport_name, NULL,
 359                                   chan_param->subbuf_size,
 360                                   chan_param->num_subbuf,
 361                                   chan_param->switch_timer_interval,
 362                                   chan_param->read_timer_interval,
 363                                   channel_type);
 364         if (!chan) {
 365                 ret = -EINVAL;
 366                 goto chan_error;
 367         }
 368         chan->file = chan_file;
 369         chan_file->private_data = chan;
 370         fd_install(chan_fd, chan_file);
 371         atomic_long_inc(&session_file->f_count);
 372
 373         return chan_fd;
 374
 375 chan_error:
 376         fput(chan_file);
 377 file_error:
 378         put_unused_fd(chan_fd);
 379 fd_error:
 380         return ret;
 381 }
 382
 383 /**
 384  *      lttng_session_ioctl - lttng session fd ioctl
 385  *
 386  *      @file: the file
 387  *      @cmd: the command
 388  *      @arg: command arg
 389  *
 390  *      This ioctl implements lttng commands:
 391  *      LTTNG_KERNEL_CHANNEL
 392  *              Returns a LTTng channel file descriptor
 393  *      LTTNG_KERNEL_ENABLE
 394  *              Enables tracing for a session (weak enable)
 395  *      LTTNG_KERNEL_DISABLE
 396  *              Disables tracing for a session (strong disable)
 397  *      LTTNG_KERNEL_METADATA
 398  *              Returns a LTTng metadata file descriptor
 399  *
 400  * The returned channel will be deleted when its file descriptor is closed.
 401  */
 402 static
 403 long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 404 {
 405         struct lttng_session *session = file->private_data;
 406
 407         switch (cmd) {
 408         case LTTNG_KERNEL_OLD_CHANNEL:
 409         {
 410                 struct lttng_kernel_channel chan_param;
 411                 struct lttng_kernel_old_channel old_chan_param;
 412
 413                 if (copy_from_user(&old_chan_param,
 414                                 (struct lttng_kernel_old_channel __user *) arg,
 415                                 sizeof(struct lttng_kernel_old_channel)))
 416                         return -EFAULT;
 417                 chan_param.overwrite = old_chan_param.overwrite;
 418                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 419                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 420                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 421                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 422                 chan_param.output = old_chan_param.output;
 423
 424                 return lttng_abi_create_channel(file, &chan_param,
 425                                 PER_CPU_CHANNEL);
 426         }
 427         case LTTNG_KERNEL_CHANNEL:
 428         {
 429                 struct lttng_kernel_channel chan_param;
 430
 431                 if (copy_from_user(&chan_param,
 432                                 (struct lttng_kernel_channel __user *) arg,
 433                                 sizeof(struct lttng_kernel_channel)))
 434                         return -EFAULT;
 435                 return lttng_abi_create_channel(file, &chan_param,
 436                                 PER_CPU_CHANNEL);
 437         }
 438         case LTTNG_KERNEL_OLD_SESSION_START:
 439         case LTTNG_KERNEL_OLD_ENABLE:
 440         case LTTNG_KERNEL_SESSION_START:
 441         case LTTNG_KERNEL_ENABLE:
 442                 return lttng_session_enable(session);
 443         case LTTNG_KERNEL_OLD_SESSION_STOP:
 444         case LTTNG_KERNEL_OLD_DISABLE:
 445         case LTTNG_KERNEL_SESSION_STOP:
 446         case LTTNG_KERNEL_DISABLE:
 447                 return lttng_session_disable(session);
 448         case LTTNG_KERNEL_OLD_METADATA:
 449         {
 450                 struct lttng_kernel_channel chan_param;
 451                 struct lttng_kernel_old_channel old_chan_param;
 452
 453                 if (copy_from_user(&old_chan_param,
 454                                 (struct lttng_kernel_old_channel __user *) arg,
 455                                 sizeof(struct lttng_kernel_old_channel)))
 456                         return -EFAULT;
 457                 chan_param.overwrite = old_chan_param.overwrite;
 458                 chan_param.subbuf_size = old_chan_param.subbuf_size;
 459                 chan_param.num_subbuf = old_chan_param.num_subbuf;
 460                 chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
 461                 chan_param.read_timer_interval = old_chan_param.read_timer_interval;
 462                 chan_param.output = old_chan_param.output;
 463
 464                 return lttng_abi_create_channel(file, &chan_param,
 465                                 METADATA_CHANNEL);
 466         }
 467         case LTTNG_KERNEL_METADATA:
 468         {
 469                 struct lttng_kernel_channel chan_param;
 470
 471                 if (copy_from_user(&chan_param,
 472                                         (struct lttng_kernel_channel __user *) arg,
 473                                         sizeof(struct lttng_kernel_channel)))
 474                         return -EFAULT;
 475                 return lttng_abi_create_channel(file, &chan_param,
 476                                 METADATA_CHANNEL);
 477         }
 478         default:
 479                 return -ENOIOCTLCMD;
 480         }
 481 }
 482
 483 /*
 484  * Called when the last file reference is dropped.
 485  *
 486  * Big fat note: channels and events are invariant for the whole session after
 487  * their creation. So this session destruction also destroys all channel and
 488  * event structures specific to this session (they are not destroyed when their
 489  * individual file is released).
 490  */
 491 static
 492 int lttng_session_release(struct inode *inode, struct file *file)
 493 {
 494         struct lttng_session *session = file->private_data;
 495
 496         if (session)
 497                 lttng_session_destroy(session);
 498         return 0;
 499 }
 500
 501 static const struct file_operations lttng_session_fops = {
 502         .owner = THIS_MODULE,
 503         .release = lttng_session_release,
 504         .unlocked_ioctl = lttng_session_ioctl,
 505 #ifdef CONFIG_COMPAT
 506         .compat_ioctl = lttng_session_ioctl,
 507 #endif
 508 };
 509
 510 /**
 511  *      lttng_metadata_ring_buffer_poll - LTTng ring buffer poll file operation
 512  *      @filp: the file
 513  *      @wait: poll table
 514  *
 515  *      Handles the poll operations for the metadata channels.
 516  */
 517 static
 518 unsigned int lttng_metadata_ring_buffer_poll(struct file *filp,
 519                 poll_table *wait)
 520 {
 521         struct lttng_metadata_stream *stream = filp->private_data;
 522         struct lib_ring_buffer *buf = stream->priv;
 523         int finalized;
 524         unsigned int mask = 0;
 525
 526         if (filp->f_mode & FMODE_READ) {
 527                 poll_wait_set_exclusive(wait);
 528                 poll_wait(filp, &stream->read_wait, wait);
 529
 530                 finalized = stream->finalized;
 531
 532                 /*
 533                  * lib_ring_buffer_is_finalized() contains a smp_rmb()
 534                  * ordering finalized load before offsets loads.
 535                  */
 536                 WARN_ON(atomic_long_read(&buf->active_readers) != 1);
 537
 538                 if (finalized)
 539                         mask |= POLLHUP;
 540
 541                 if (stream->metadata_cache->metadata_written >
 542                                 stream->metadata_cache_read)
 543                         mask |= POLLIN;
 544         }
 545
 546         return mask;
 547 }
 548
 549 static
 550 int lttng_metadata_ring_buffer_ioctl_get_subbuf(struct file *filp,
 551                 unsigned int cmd, unsigned long arg)
 552 {
 553         struct lttng_metadata_stream *stream = filp->private_data;
 554         struct lib_ring_buffer *buf = stream->priv;
 555         struct channel *chan = buf->backend.chan;
 556         struct lttng_channel *lttng_chan = channel_get_private(chan);
 557         int ret;
 558
 559         ret = lttng_metadata_output_channel(lttng_chan, stream);
 560         if (ret > 0) {
 561                 lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 562                 ret = 0;
 563         }
 564         return ret;
 565 }
 566
 567 static
 568 long lttng_metadata_ring_buffer_ioctl(struct file *filp,
 569                 unsigned int cmd, unsigned long arg)
 570 {
 571         int ret;
 572         struct lttng_metadata_stream *stream = filp->private_data;
 573         struct lib_ring_buffer *buf = stream->priv;
 574
 575         switch (cmd) {
 576         case RING_BUFFER_GET_SUBBUF:
 577         case RING_BUFFER_GET_NEXT_SUBBUF:
 578         {
 579                 ret = lttng_metadata_ring_buffer_ioctl_get_subbuf(filp,
 580                                 cmd, arg);
 581                 if (ret < 0)
 582                         goto err;
 583                 break;
 584         }
 585         default:
 586                 break;
 587         }
 588         /* Performing lib ring buffer ioctl after our own. */
 589         return lib_ring_buffer_ioctl(filp, cmd, arg, buf);
 590
 591 err:
 592         return ret;
 593 }
 594
 595 static
 596 long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 597                 unsigned int cmd, unsigned long arg)
 598 {
 599         int ret;
 600         struct lttng_metadata_stream *stream = filp->private_data;
 601         struct lib_ring_buffer *buf = stream->priv;
 602
 603         switch (cmd) {
 604         case RING_BUFFER_GET_SUBBUF:
 605         case RING_BUFFER_GET_NEXT_SUBBUF:
 606         {
 607                 ret = lttng_metadata_ring_buffer_ioctl_get_subbuf(filp,
 608                                 cmd, arg);
 609                 if (ret < 0)
 610                         goto err;
 611                 break;
 612         }
 613         default:
 614                 break;
 615         }
 616         /* Performing lib ring buffer ioctl after our own. */
 617         return lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
 618
 619 err:
 620         return ret;
 621 }
 622
 623 static
 624 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 625 {
 626         struct lttng_metadata_stream *stream = inode->i_private;
 627         struct lib_ring_buffer *buf = stream->priv;
 628
 629         file->private_data = buf;
 630         return lib_ring_buffer_open(inode, file, buf);
 631 }
 632
 633 static
 634 int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 635 {
 636         struct lttng_metadata_stream *stream = file->private_data;
 637         struct lib_ring_buffer *buf = stream->priv;
 638
 639         kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
 640
 641         return lib_ring_buffer_release(inode, file, buf);
 642 }
 643
 644 static
 645 ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
 646                 struct pipe_inode_info *pipe, size_t len,
 647                 unsigned int flags)
 648 {
 649         struct lttng_metadata_stream *stream = in->private_data;
 650         struct lib_ring_buffer *buf = stream->priv;
 651
 652         return lib_ring_buffer_splice_read(in, ppos, pipe, len,
 653                         flags, buf);
 654 }
 655
 656 static
 657 int lttng_metadata_ring_buffer_mmap(struct file *filp,
 658                 struct vm_area_struct *vma)
 659 {
 660         struct lttng_metadata_stream *stream = filp->private_data;
 661         struct lib_ring_buffer *buf = stream->priv;
 662
 663         return lib_ring_buffer_mmap(filp, vma, buf);
 664 }
 665
 666 static
 667 const struct file_operations lttng_metadata_ring_buffer_file_operations = {
 668         .owner = THIS_MODULE,
 669         .open = lttng_metadata_ring_buffer_open,
 670         .release = lttng_metadata_ring_buffer_release,
 671         .poll = lttng_metadata_ring_buffer_poll,
 672         .splice_read = lttng_metadata_ring_buffer_splice_read,
 673         .mmap = lttng_metadata_ring_buffer_mmap,
 674         .unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
 675         .llseek = vfs_lib_ring_buffer_no_llseek,
 676 #ifdef CONFIG_COMPAT
 677         .compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
 678 #endif
 679 };
 680
 681 static
 682 int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
 683                 const struct file_operations *fops)
 684 {
 685         int stream_fd, ret;
 686         struct file *stream_file;
 687
 688         stream_fd = get_unused_fd();
 689         if (stream_fd < 0) {
 690                 ret = stream_fd;
 691                 goto fd_error;
 692         }
 693         stream_file = anon_inode_getfile("[lttng_stream]", fops,
 694                         stream_priv, O_RDWR);
 695         if (IS_ERR(stream_file)) {
 696                 ret = PTR_ERR(stream_file);
 697                 goto file_error;
 698         }
 699         /*
 700          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
 701          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
 702          * file descriptor, so we set FMODE_PREAD here.
 703          */
 704         stream_file->f_mode |= FMODE_PREAD;
 705         fd_install(stream_fd, stream_file);
 706         /*
 707          * The stream holds a reference to the channel within the generic ring
 708          * buffer library, so no need to hold a refcount on the channel and
 709          * session files here.
 710          */
 711         return stream_fd;
 712
 713 file_error:
 714         put_unused_fd(stream_fd);
 715 fd_error:
 716         return ret;
 717 }
 718
 719 static
 720 int lttng_abi_open_stream(struct file *channel_file)
 721 {
 722         struct lttng_channel *channel = channel_file->private_data;
 723         struct lib_ring_buffer *buf;
 724         int ret;
 725         void *stream_priv;
 726
 727         buf = channel->ops->buffer_read_open(channel->chan);
 728         if (!buf)
 729                 return -ENOENT;
 730
 731         stream_priv = buf;
 732         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 733                         &lib_ring_buffer_file_operations);
 734         if (ret < 0)
 735                 goto fd_error;
 736
 737         return ret;
 738
 739 fd_error:
 740         channel->ops->buffer_read_close(buf);
 741         return ret;
 742 }
 743
 744 static
 745 int lttng_abi_open_metadata_stream(struct file *channel_file)
 746 {
 747         struct lttng_channel *channel = channel_file->private_data;
 748         struct lttng_session *session = channel->session;
 749         struct lib_ring_buffer *buf;
 750         int ret;
 751         struct lttng_metadata_stream *metadata_stream;
 752         void *stream_priv;
 753
 754         buf = channel->ops->buffer_read_open(channel->chan);
 755         if (!buf)
 756                 return -ENOENT;
 757
 758         metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
 759                         GFP_KERNEL);
 760         if (!metadata_stream)
 761                 return -ENOMEM;
 762         metadata_stream->metadata_cache = session->metadata_cache;
 763         init_waitqueue_head(&metadata_stream->read_wait);
 764         metadata_stream->priv = buf;
 765         stream_priv = metadata_stream;
 766         ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 767                         &lttng_metadata_ring_buffer_file_operations);
 768         if (ret < 0)
 769                 goto fd_error;
 770
 771         kref_get(&session->metadata_cache->refcount);
 772         list_add(&metadata_stream->list,
 773                 &session->metadata_cache->metadata_stream);
 774         return ret;
 775
 776 fd_error:
 777         channel->ops->buffer_read_close(buf);
 778         return ret;
 779 }
 780
 781 static
 782 int lttng_abi_create_event(struct file *channel_file,
 783                            struct lttng_kernel_event *event_param)
 784 {
 785         struct lttng_channel *channel = channel_file->private_data;
 786         struct lttng_event *event;
 787         int event_fd, ret;
 788         struct file *event_file;
 789
 790         event_param->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 791         switch (event_param->instrumentation) {
 792         case LTTNG_KERNEL_KRETPROBE:
 793                 event_param->u.kretprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 794                 break;
 795         case LTTNG_KERNEL_KPROBE:
 796                 event_param->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 797                 break;
 798         case LTTNG_KERNEL_FUNCTION:
 799                 event_param->u.ftrace.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 800                 break;
 801         default:
 802                 break;
 803         }
 804         switch (event_param->instrumentation) {
 805         default:
 806                 event_fd = get_unused_fd();
 807                 if (event_fd < 0) {
 808                         ret = event_fd;
 809                         goto fd_error;
 810                 }
 811                 event_file = anon_inode_getfile("[lttng_event]",
 812                                                 &lttng_event_fops,
 813                                                 NULL, O_RDWR);
 814                 if (IS_ERR(event_file)) {
 815                         ret = PTR_ERR(event_file);
 816                         goto file_error;
 817                 }
 818                 /*
 819                  * We tolerate no failure path after event creation. It
 820                  * will stay invariant for the rest of the session.
 821                  */
 822                 event = lttng_event_create(channel, event_param, NULL, NULL);
 823                 if (!event) {
 824                         ret = -EINVAL;
 825                         goto event_error;
 826                 }
 827                 event_file->private_data = event;
 828                 fd_install(event_fd, event_file);
 829                 /* The event holds a reference on the channel */
 830                 atomic_long_inc(&channel_file->f_count);
 831                 break;
 832         case LTTNG_KERNEL_SYSCALL:
 833                 /*
 834                  * Only all-syscall tracing supported for now.
 835                  */
 836                 if (event_param->name[0] != '\0')
 837                         return -EINVAL;
 838                 ret = lttng_syscalls_register(channel, NULL);
 839                 if (ret)
 840                         goto fd_error;
 841                 event_fd = 0;
 842                 break;
 843         }
 844         return event_fd;
 845
 846 event_error:
 847         fput(event_file);
 848 file_error:
 849         put_unused_fd(event_fd);
 850 fd_error:
 851         return ret;
 852 }
 853
 854 /**
 855  *      lttng_channel_ioctl - lttng syscall through ioctl
 856  *
 857  *      @file: the file
 858  *      @cmd: the command
 859  *      @arg: command arg
 860  *
 861  *      This ioctl implements lttng commands:
 862  *      LTTNG_KERNEL_STREAM
 863  *              Returns an event stream file descriptor or failure.
 864  *              (typically, one event stream records events from one CPU)
 865  *      LTTNG_KERNEL_EVENT
 866  *              Returns an event file descriptor or failure.
 867  *      LTTNG_KERNEL_CONTEXT
 868  *              Prepend a context field to each event in the channel
 869  *      LTTNG_KERNEL_ENABLE
 870  *              Enable recording for events in this channel (weak enable)
 871  *      LTTNG_KERNEL_DISABLE
 872  *              Disable recording for events in this channel (strong disable)
 873  *
 874  * Channel and event file descriptors also hold a reference on the session.
 875  */
 876 static
 877 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 878 {
 879         struct lttng_channel *channel = file->private_data;
 880
 881         switch (cmd) {
 882         case LTTNG_KERNEL_OLD_STREAM:
 883         case LTTNG_KERNEL_STREAM:
 884                 return lttng_abi_open_stream(file);
 885         case LTTNG_KERNEL_OLD_EVENT:
 886         {
 887                 struct lttng_kernel_event *uevent_param;
 888                 struct lttng_kernel_old_event *old_uevent_param;
 889                 int ret;
 890
 891                 uevent_param = kmalloc(sizeof(struct lttng_kernel_event),
 892                                 GFP_KERNEL);
 893                 if (!uevent_param) {
 894                         ret = -ENOMEM;
 895                         goto old_event_end;
 896                 }
 897                 old_uevent_param = kmalloc(
 898                                 sizeof(struct lttng_kernel_old_event),
 899                                 GFP_KERNEL);
 900                 if (!old_uevent_param) {
 901                         ret = -ENOMEM;
 902                         goto old_event_error_free_param;
 903                 }
 904                 if (copy_from_user(old_uevent_param,
 905                                 (struct lttng_kernel_old_event __user *) arg,
 906                                 sizeof(struct lttng_kernel_old_event))) {
 907                         ret = -EFAULT;
 908                         goto old_event_error_free_old_param;
 909                 }
 910
 911                 memcpy(uevent_param->name, old_uevent_param->name,
 912                                 sizeof(uevent_param->name));
 913                 uevent_param->instrumentation =
 914                         old_uevent_param->instrumentation;
 915
 916                 switch (old_uevent_param->instrumentation) {
 917                 case LTTNG_KERNEL_KPROBE:
 918                         uevent_param->u.kprobe.addr =
 919                                 old_uevent_param->u.kprobe.addr;
 920                         uevent_param->u.kprobe.offset =
 921                                 old_uevent_param->u.kprobe.offset;
 922                         memcpy(uevent_param->u.kprobe.symbol_name,
 923                                 old_uevent_param->u.kprobe.symbol_name,
 924                                 sizeof(uevent_param->u.kprobe.symbol_name));
 925                         break;
 926                 case LTTNG_KERNEL_KRETPROBE:
 927                         uevent_param->u.kretprobe.addr =
 928                                 old_uevent_param->u.kretprobe.addr;
 929                         uevent_param->u.kretprobe.offset =
 930                                 old_uevent_param->u.kretprobe.offset;
 931                         memcpy(uevent_param->u.kretprobe.symbol_name,
 932                                 old_uevent_param->u.kretprobe.symbol_name,
 933                                 sizeof(uevent_param->u.kretprobe.symbol_name));
 934                         break;
 935                 case LTTNG_KERNEL_FUNCTION:
 936                         memcpy(uevent_param->u.ftrace.symbol_name,
 937                                         old_uevent_param->u.ftrace.symbol_name,
 938                                         sizeof(uevent_param->u.ftrace.symbol_name));
 939                         break;
 940                 default:
 941                         break;
 942                 }
 943                 ret = lttng_abi_create_event(file, uevent_param);
 944
 945 old_event_error_free_old_param:
 946                 kfree(old_uevent_param);
 947 old_event_error_free_param:
 948                 kfree(uevent_param);
 949 old_event_end:
 950                 return ret;
 951         }
 952         case LTTNG_KERNEL_EVENT:
 953         {
 954                 struct lttng_kernel_event uevent_param;
 955
 956                 if (copy_from_user(&uevent_param,
 957                                 (struct lttng_kernel_event __user *) arg,
 958                                 sizeof(uevent_param)))
 959                         return -EFAULT;
 960                 return lttng_abi_create_event(file, &uevent_param);
 961         }
 962         case LTTNG_KERNEL_OLD_CONTEXT:
 963         {
 964                 struct lttng_kernel_context *ucontext_param;
 965                 struct lttng_kernel_old_context *old_ucontext_param;
 966                 int ret;
 967
 968                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
 969                                 GFP_KERNEL);
 970                 if (!ucontext_param) {
 971                         ret = -ENOMEM;
 972                         goto old_ctx_end;
 973                 }
 974                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
 975                                 GFP_KERNEL);
 976                 if (!old_ucontext_param) {
 977                         ret = -ENOMEM;
 978                         goto old_ctx_error_free_param;
 979                 }
 980
 981                 if (copy_from_user(old_ucontext_param,
 982                                 (struct lttng_kernel_old_context __user *) arg,
 983                                 sizeof(struct lttng_kernel_old_context))) {
 984                         ret = -EFAULT;
 985                         goto old_ctx_error_free_old_param;
 986                 }
 987                 ucontext_param->ctx = old_ucontext_param->ctx;
 988                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
 989                                 sizeof(ucontext_param->padding));
 990                 /* only type that uses the union */
 991                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
 992                         ucontext_param->u.perf_counter.type =
 993                                 old_ucontext_param->u.perf_counter.type;
 994                         ucontext_param->u.perf_counter.config =
 995                                 old_ucontext_param->u.perf_counter.config;
 996                         memcpy(ucontext_param->u.perf_counter.name,
 997                                 old_ucontext_param->u.perf_counter.name,
 998                                 sizeof(ucontext_param->u.perf_counter.name));
 999                 }
1000
1001                 ret = lttng_abi_add_context(file,
1002                                 ucontext_param,
1003                                 &channel->ctx, channel->session);
1004
1005 old_ctx_error_free_old_param:
1006                 kfree(old_ucontext_param);
1007 old_ctx_error_free_param:
1008                 kfree(ucontext_param);
1009 old_ctx_end:
1010                 return ret;
1011         }
1012         case LTTNG_KERNEL_CONTEXT:
1013         {
1014                 struct lttng_kernel_context ucontext_param;
1015
1016                 if (copy_from_user(&ucontext_param,
1017                                 (struct lttng_kernel_context __user *) arg,
1018                                 sizeof(ucontext_param)))
1019                         return -EFAULT;
1020                 return lttng_abi_add_context(file,
1021                                 &ucontext_param,
1022                                 &channel->ctx, channel->session);
1023         }
1024         case LTTNG_KERNEL_OLD_ENABLE:
1025         case LTTNG_KERNEL_ENABLE:
1026                 return lttng_channel_enable(channel);
1027         case LTTNG_KERNEL_OLD_DISABLE:
1028         case LTTNG_KERNEL_DISABLE:
1029                 return lttng_channel_disable(channel);
1030         default:
1031                 return -ENOIOCTLCMD;
1032         }
1033
1034 }
1035
1036 /**
1037  *      lttng_metadata_ioctl - lttng syscall through ioctl
1038  *
1039  *      @file: the file
1040  *      @cmd: the command
1041  *      @arg: command arg
1042  *
1043  *      This ioctl implements lttng commands:
1044  *      LTTNG_KERNEL_STREAM
1045  *              Returns an event stream file descriptor or failure.
1046  *
1047  * Channel and event file descriptors also hold a reference on the session.
1048  */
1049 static
1050 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1051 {
1052         switch (cmd) {
1053         case LTTNG_KERNEL_OLD_STREAM:
1054         case LTTNG_KERNEL_STREAM:
1055                 return lttng_abi_open_metadata_stream(file);
1056         default:
1057                 return -ENOIOCTLCMD;
1058         }
1059 }
1060
1061 /**
1062  *      lttng_channel_poll - lttng stream addition/removal monitoring
1063  *
1064  *      @file: the file
1065  *      @wait: poll table
1066  */
1067 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
1068 {
1069         struct lttng_channel *channel = file->private_data;
1070         unsigned int mask = 0;
1071
1072         if (file->f_mode & FMODE_READ) {
1073                 poll_wait_set_exclusive(wait);
1074                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
1075                           wait);
1076
1077                 if (channel->ops->is_disabled(channel->chan))
1078                         return POLLERR;
1079                 if (channel->ops->is_finalized(channel->chan))
1080                         return POLLHUP;
1081                 if (channel->ops->buffer_has_read_closed_stream(channel->chan))
1082                         return POLLIN | POLLRDNORM;
1083                 return 0;
1084         }
1085         return mask;
1086
1087 }
1088
1089 static
1090 int lttng_channel_release(struct inode *inode, struct file *file)
1091 {
1092         struct lttng_channel *channel = file->private_data;
1093
1094         if (channel)
1095                 fput(channel->session->file);
1096         return 0;
1097 }
1098
1099 static
1100 int lttng_metadata_channel_release(struct inode *inode, struct file *file)
1101 {
1102         struct lttng_channel *channel = file->private_data;
1103
1104         if (channel) {
1105                 lttng_metadata_channel_destroy(channel);
1106                 fput(channel->session->file);
1107         }
1108
1109         return 0;
1110 }
1111
1112 static const struct file_operations lttng_channel_fops = {
1113         .owner = THIS_MODULE,
1114         .release = lttng_channel_release,
1115         .poll = lttng_channel_poll,
1116         .unlocked_ioctl = lttng_channel_ioctl,
1117 #ifdef CONFIG_COMPAT
1118         .compat_ioctl = lttng_channel_ioctl,
1119 #endif
1120 };
1121
1122 static const struct file_operations lttng_metadata_fops = {
1123         .owner = THIS_MODULE,
1124         .release = lttng_metadata_channel_release,
1125         .unlocked_ioctl = lttng_metadata_ioctl,
1126 #ifdef CONFIG_COMPAT
1127         .compat_ioctl = lttng_metadata_ioctl,
1128 #endif
1129 };
1130
1131 /**
1132  *      lttng_event_ioctl - lttng syscall through ioctl
1133  *
1134  *      @file: the file
1135  *      @cmd: the command
1136  *      @arg: command arg
1137  *
1138  *      This ioctl implements lttng commands:
1139  *      LTTNG_KERNEL_CONTEXT
1140  *              Prepend a context field to each record of this event
1141  *      LTTNG_KERNEL_ENABLE
1142  *              Enable recording for this event (weak enable)
1143  *      LTTNG_KERNEL_DISABLE
1144  *              Disable recording for this event (strong disable)
1145  */
1146 static
1147 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1148 {
1149         struct lttng_event *event = file->private_data;
1150
1151         switch (cmd) {
1152         case LTTNG_KERNEL_OLD_CONTEXT:
1153         {
1154                 struct lttng_kernel_context *ucontext_param;
1155                 struct lttng_kernel_old_context *old_ucontext_param;
1156                 int ret;
1157
1158                 ucontext_param = kmalloc(sizeof(struct lttng_kernel_context),
1159                                 GFP_KERNEL);
1160                 if (!ucontext_param) {
1161                         ret = -ENOMEM;
1162                         goto old_ctx_end;
1163                 }
1164                 old_ucontext_param = kmalloc(sizeof(struct lttng_kernel_old_context),
1165                                 GFP_KERNEL);
1166                 if (!old_ucontext_param) {
1167                         ret = -ENOMEM;
1168                         goto old_ctx_error_free_param;
1169                 }
1170
1171                 if (copy_from_user(old_ucontext_param,
1172                                         (struct lttng_kernel_old_context __user *) arg,
1173                                         sizeof(struct lttng_kernel_old_context))) {
1174                         ret = -EFAULT;
1175                         goto old_ctx_error_free_old_param;
1176                 }
1177                 ucontext_param->ctx = old_ucontext_param->ctx;
1178                 memcpy(ucontext_param->padding, old_ucontext_param->padding,
1179                                 sizeof(ucontext_param->padding));
1180                 /* only type that uses the union */
1181                 if (old_ucontext_param->ctx == LTTNG_KERNEL_CONTEXT_PERF_COUNTER) {
1182                         ucontext_param->u.perf_counter.type =
1183                                 old_ucontext_param->u.perf_counter.type;
1184                         ucontext_param->u.perf_counter.config =
1185                                 old_ucontext_param->u.perf_counter.config;
1186                         memcpy(ucontext_param->u.perf_counter.name,
1187                                         old_ucontext_param->u.perf_counter.name,
1188                                         sizeof(ucontext_param->u.perf_counter.name));
1189                 }
1190
1191                 ret = lttng_abi_add_context(file,
1192                                 ucontext_param,
1193                                 &event->ctx, event->chan->session);
1194
1195 old_ctx_error_free_old_param:
1196                 kfree(old_ucontext_param);
1197 old_ctx_error_free_param:
1198                 kfree(ucontext_param);
1199 old_ctx_end:
1200                 return ret;
1201         }
1202         case LTTNG_KERNEL_CONTEXT:
1203         {
1204                 struct lttng_kernel_context ucontext_param;
1205
1206                 if (copy_from_user(&ucontext_param,
1207                                         (struct lttng_kernel_context __user *) arg,
1208                                         sizeof(ucontext_param)))
1209                         return -EFAULT;
1210                 return lttng_abi_add_context(file,
1211                                 &ucontext_param,
1212                                 &event->ctx, event->chan->session);
1213         }
1214         case LTTNG_KERNEL_OLD_ENABLE:
1215         case LTTNG_KERNEL_ENABLE:
1216                 return lttng_event_enable(event);
1217         case LTTNG_KERNEL_OLD_DISABLE:
1218         case LTTNG_KERNEL_DISABLE:
1219                 return lttng_event_disable(event);
1220         default:
1221                 return -ENOIOCTLCMD;
1222         }
1223 }
1224
1225 static
1226 int lttng_event_release(struct inode *inode, struct file *file)
1227 {
1228         struct lttng_event *event = file->private_data;
1229
1230         if (event)
1231                 fput(event->chan->file);
1232         return 0;
1233 }
1234
1235 /* TODO: filter control ioctl */
1236 static const struct file_operations lttng_event_fops = {
1237         .owner = THIS_MODULE,
1238         .release = lttng_event_release,
1239         .unlocked_ioctl = lttng_event_ioctl,
1240 #ifdef CONFIG_COMPAT
1241         .compat_ioctl = lttng_event_ioctl,
1242 #endif
1243 };
1244
1245 int __init lttng_abi_init(void)
1246 {
1247         int ret = 0;
1248
1249         wrapper_vmalloc_sync_all();
1250         lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
1251                                         &lttng_fops, NULL);
1252
1253         if (!lttng_proc_dentry) {
1254                 printk(KERN_ERR "Error creating LTTng control file\n");
1255                 ret = -ENOMEM;
1256                 goto error;
1257         }
1258 error:
1259         return ret;
1260 }
1261
1262 void __exit lttng_abi_exit(void)
1263 {
1264         if (lttng_proc_dentry)
1265                 remove_proc_entry("lttng", NULL);
1266 }