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lttng-abi.c
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/*
* lttng-abi.c
*
* LTTng ABI
*
* Copyright (C) 2010-2012 Mathieu Desnoyers <[email protected]>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; only
* version 2.1 of the License.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
*
* Mimic system calls for:
* - session creation, returns a file descriptor or failure.
* - channel creation, returns a file descriptor or failure.
* - Operates on a session file descriptor
* - Takes all channel options as parameters.
* - stream get, returns a file descriptor or failure.
* - Operates on a channel file descriptor.
* - stream notifier get, returns a file descriptor or failure.
* - Operates on a channel file descriptor.
* - event creation, returns a file descriptor or failure.
* - Operates on a channel file descriptor
* - Takes an event name as parameter
* - Takes an instrumentation source as parameter
* - e.g. tracepoints, dynamic_probes...
* - Takes instrumentation source specific arguments.
*/
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/anon_inodes.h>
#include <linux/file.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <wrapper/vmalloc.h> /* for wrapper_vmalloc_sync_all() */
#include <wrapper/ringbuffer/vfs.h>
#include <wrapper/ringbuffer/backend.h>
#include <wrapper/ringbuffer/frontend.h>
#include <wrapper/poll.h>
#include <wrapper/file.h>
#include <wrapper/kref.h>
#include <lttng-string-utils.h>
#include <lttng-abi.h>
#include <lttng-abi-old.h>
#include <lttng-events.h>
#include <lttng-tracer.h>
#include <lttng-tp-mempool.h>
#include <lib/ringbuffer/frontend_types.h>
/*
* This is LTTng's own personal way to create a system call as an external
* module. We use ioctl() on /proc/lttng.
*/
static struct proc_dir_entry *lttng_proc_dentry;
static const struct file_operations lttng_fops;
static const struct file_operations lttng_session_fops;
static const struct file_operations lttng_channel_fops;
static const struct file_operations lttng_metadata_fops;
static const struct file_operations lttng_event_fops;
static struct file_operations lttng_stream_ring_buffer_file_operations;
static int put_u64(uint64_t val, unsigned long arg);
/*
* Teardown management: opened file descriptors keep a refcount on the module,
* so it can only exit when all file descriptors are closed.
*/
static
int lttng_abi_create_session(void)
{
struct lttng_session *session;
struct file *session_file;
int session_fd, ret;
session = lttng_session_create();
if (!session)
return -ENOMEM;
session_fd = lttng_get_unused_fd();
if (session_fd < 0) {
ret = session_fd;
goto fd_error;
}
session_file = anon_inode_getfile("[lttng_session]",
<tng_session_fops,
session, O_RDWR);
if (IS_ERR(session_file)) {
ret = PTR_ERR(session_file);
goto file_error;
}
session->file = session_file;
fd_install(session_fd, session_file);
return session_fd;
file_error:
put_unused_fd(session_fd);
fd_error:
lttng_session_destroy(session);
return ret;
}
static
int lttng_abi_tracepoint_list(void)
{
struct file *tracepoint_list_file;
int file_fd, ret;
file_fd = lttng_get_unused_fd();
if (file_fd < 0) {
ret = file_fd;
goto fd_error;
}
tracepoint_list_file = anon_inode_getfile("[lttng_tracepoint_list]",
<tng_tracepoint_list_fops,
NULL, O_RDWR);
if (IS_ERR(tracepoint_list_file)) {
ret = PTR_ERR(tracepoint_list_file);
goto file_error;
}
ret = lttng_tracepoint_list_fops.open(NULL, tracepoint_list_file);
if (ret < 0)
goto open_error;
fd_install(file_fd, tracepoint_list_file);
return file_fd;
open_error:
fput(tracepoint_list_file);
file_error:
put_unused_fd(file_fd);
fd_error:
return ret;
}
#ifndef CONFIG_HAVE_SYSCALL_TRACEPOINTS
static inline
int lttng_abi_syscall_list(void)
{
return -ENOSYS;
}
#else
static
int lttng_abi_syscall_list(void)
{
struct file *syscall_list_file;
int file_fd, ret;
file_fd = lttng_get_unused_fd();
if (file_fd < 0) {
ret = file_fd;
goto fd_error;
}
syscall_list_file = anon_inode_getfile("[lttng_syscall_list]",
<tng_syscall_list_fops,
NULL, O_RDWR);
if (IS_ERR(syscall_list_file)) {
ret = PTR_ERR(syscall_list_file);
goto file_error;
}
ret = lttng_syscall_list_fops.open(NULL, syscall_list_file);
if (ret < 0)
goto open_error;
fd_install(file_fd, syscall_list_file);
return file_fd;
open_error:
fput(syscall_list_file);
file_error:
put_unused_fd(file_fd);
fd_error:
return ret;
}
#endif
static
void lttng_abi_tracer_version(struct lttng_kernel_tracer_version *v)
{
v->major = LTTNG_MODULES_MAJOR_VERSION;
v->minor = LTTNG_MODULES_MINOR_VERSION;
v->patchlevel = LTTNG_MODULES_PATCHLEVEL_VERSION;
}
static
void lttng_abi_tracer_abi_version(struct lttng_kernel_tracer_abi_version *v)
{
v->major = LTTNG_MODULES_ABI_MAJOR_VERSION;
v->minor = LTTNG_MODULES_ABI_MINOR_VERSION;
}
static
long lttng_abi_add_context(struct file *file,
struct lttng_kernel_context *context_param,
struct lttng_ctx **ctx, struct lttng_session *session)
{
if (session->been_active)
return -EPERM;
switch (context_param->ctx) {
case LTTNG_KERNEL_CONTEXT_PID:
return lttng_add_pid_to_ctx(ctx);
case LTTNG_KERNEL_CONTEXT_PRIO:
return lttng_add_prio_to_ctx(ctx);
case LTTNG_KERNEL_CONTEXT_NICE:
return lttng_add_nice_to_ctx(ctx);
case LTTNG_KERNEL_CONTEXT_VPID:
return lttng_add_vpid_to_ctx(ctx);
case LTTNG_KERNEL_CONTEXT_TID:
return lttng_add_tid_to_ctx(ctx);
case LTTNG_KERNEL_CONTEXT_VTID:
return lttng_add_vtid_to_ctx(ctx);
case LTTNG_KERNEL_CONTEXT_PPID:
return lttng_add_ppid_to_ctx(ctx);
case LTTNG_KERNEL_CONTEXT_VPPID:
return lttng_add_vppid_to_ctx(ctx);
case LTTNG_KERNEL_CONTEXT_PERF_COUNTER:
context_param->u.perf_counter.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
return lttng_add_perf_counter_to_ctx(context_param->u.perf_counter.type,
context_param->u.perf_counter.config,
context_param->u.perf_counter.name,
ctx);
case LTTNG_KERNEL_CONTEXT_PROCNAME:
return lttng_add_procname_to_ctx(ctx);
case LTTNG_KERNEL_CONTEXT_HOSTNAME:
return lttng_add_hostname_to_ctx(ctx);
case LTTNG_KERNEL_CONTEXT_CPU_ID:
return lttng_add_cpu_id_to_ctx(ctx);
case LTTNG_KERNEL_CONTEXT_INTERRUPTIBLE:
return lttng_add_interruptible_to_ctx(ctx);
case LTTNG_KERNEL_CONTEXT_NEED_RESCHEDULE:
return lttng_add_need_reschedule_to_ctx(ctx);
case LTTNG_KERNEL_CONTEXT_PREEMPTIBLE:
return lttng_add_preemptible_to_ctx(ctx);
case LTTNG_KERNEL_CONTEXT_MIGRATABLE:
return lttng_add_migratable_to_ctx(ctx);
default:
return -EINVAL;
}
}
/**
* lttng_ioctl - lttng syscall through ioctl
*
* @file: the file
* @cmd: the command
* @arg: command arg
*
* This ioctl implements lttng commands:
* LTTNG_KERNEL_SESSION
* Returns a LTTng trace session file descriptor
* LTTNG_KERNEL_TRACER_VERSION
* Returns the LTTng kernel tracer version
* LTTNG_KERNEL_TRACEPOINT_LIST
* Returns a file descriptor listing available tracepoints
* LTTNG_KERNEL_WAIT_QUIESCENT
* Returns after all previously running probes have completed
* LTTNG_KERNEL_TRACER_ABI_VERSION
* Returns the LTTng kernel tracer ABI version
*
* The returned session will be deleted when its file descriptor is closed.
*/
static
long lttng_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
switch (cmd) {
case LTTNG_KERNEL_OLD_SESSION:
case LTTNG_KERNEL_SESSION:
return lttng_abi_create_session();
case LTTNG_KERNEL_OLD_TRACER_VERSION:
{
struct lttng_kernel_tracer_version v;
struct lttng_kernel_old_tracer_version oldv;
struct lttng_kernel_old_tracer_version *uversion =
(struct lttng_kernel_old_tracer_version __user *) arg;
lttng_abi_tracer_version(&v);
oldv.major = v.major;
oldv.minor = v.minor;
oldv.patchlevel = v.patchlevel;
if (copy_to_user(uversion, &oldv, sizeof(oldv)))
return -EFAULT;
return 0;
}
case LTTNG_KERNEL_TRACER_VERSION:
{
struct lttng_kernel_tracer_version version;
struct lttng_kernel_tracer_version *uversion =
(struct lttng_kernel_tracer_version __user *) arg;
lttng_abi_tracer_version(&version);
if (copy_to_user(uversion, &version, sizeof(version)))
return -EFAULT;
return 0;
}
case LTTNG_KERNEL_TRACER_ABI_VERSION:
{
struct lttng_kernel_tracer_abi_version version;
struct lttng_kernel_tracer_abi_version *uversion =
(struct lttng_kernel_tracer_abi_version __user *) arg;
lttng_abi_tracer_abi_version(&version);
if (copy_to_user(uversion, &version, sizeof(version)))
return -EFAULT;
return 0;
}
case LTTNG_KERNEL_OLD_TRACEPOINT_LIST:
case LTTNG_KERNEL_TRACEPOINT_LIST:
return lttng_abi_tracepoint_list();
case LTTNG_KERNEL_SYSCALL_LIST:
return lttng_abi_syscall_list();
case LTTNG_KERNEL_OLD_WAIT_QUIESCENT:
case LTTNG_KERNEL_WAIT_QUIESCENT:
synchronize_trace();
return 0;
case LTTNG_KERNEL_OLD_CALIBRATE:
{
struct lttng_kernel_old_calibrate __user *ucalibrate =
(struct lttng_kernel_old_calibrate __user *) arg;
struct lttng_kernel_old_calibrate old_calibrate;
struct lttng_kernel_calibrate calibrate;
int ret;
if (copy_from_user(&old_calibrate, ucalibrate, sizeof(old_calibrate)))
return -EFAULT;
calibrate.type = old_calibrate.type;
ret = lttng_calibrate(&calibrate);
if (copy_to_user(ucalibrate, &old_calibrate, sizeof(old_calibrate)))
return -EFAULT;
return ret;
}
case LTTNG_KERNEL_CALIBRATE:
{
struct lttng_kernel_calibrate __user *ucalibrate =
(struct lttng_kernel_calibrate __user *) arg;
struct lttng_kernel_calibrate calibrate;
int ret;
if (copy_from_user(&calibrate, ucalibrate, sizeof(calibrate)))
return -EFAULT;
ret = lttng_calibrate(&calibrate);
if (copy_to_user(ucalibrate, &calibrate, sizeof(calibrate)))
return -EFAULT;
return ret;
}
default:
return -ENOIOCTLCMD;
}
}
static const struct file_operations lttng_fops = {
.owner = THIS_MODULE,
.unlocked_ioctl = lttng_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = lttng_ioctl,
#endif
};
static
int lttng_abi_create_channel(struct file *session_file,
struct lttng_kernel_channel *chan_param,
enum channel_type channel_type)
{
struct lttng_session *session = session_file->private_data;
const struct file_operations *fops = NULL;
const char *transport_name;
struct lttng_channel *chan;
struct file *chan_file;
int chan_fd;
int ret = 0;
chan_fd = lttng_get_unused_fd();
if (chan_fd < 0) {
ret = chan_fd;
goto fd_error;
}
switch (channel_type) {
case PER_CPU_CHANNEL:
fops = <tng_channel_fops;
break;
case METADATA_CHANNEL:
fops = <tng_metadata_fops;
break;
}
chan_file = anon_inode_getfile("[lttng_channel]",
fops,
NULL, O_RDWR);
if (IS_ERR(chan_file)) {
ret = PTR_ERR(chan_file);
goto file_error;
}
switch (channel_type) {
case PER_CPU_CHANNEL:
if (chan_param->output == LTTNG_KERNEL_SPLICE) {
transport_name = chan_param->overwrite ?
"relay-overwrite" : "relay-discard";
} else if (chan_param->output == LTTNG_KERNEL_MMAP) {
transport_name = chan_param->overwrite ?
"relay-overwrite-mmap" : "relay-discard-mmap";
} else {
return -EINVAL;
}
break;
case METADATA_CHANNEL:
if (chan_param->output == LTTNG_KERNEL_SPLICE)
transport_name = "relay-metadata";
else if (chan_param->output == LTTNG_KERNEL_MMAP)
transport_name = "relay-metadata-mmap";
else
return -EINVAL;
break;
default:
transport_name = "<unknown>";
break;
}
if (atomic_long_add_unless(&session_file->f_count,
1, INT_MAX) == INT_MAX) {
goto refcount_error;
}
/*
* We tolerate no failure path after channel creation. It will stay
* invariant for the rest of the session.
*/
chan = lttng_channel_create(session, transport_name, NULL,
chan_param->subbuf_size,
chan_param->num_subbuf,
chan_param->switch_timer_interval,
chan_param->read_timer_interval,
channel_type);
if (!chan) {
ret = -EINVAL;
goto chan_error;
}
chan->file = chan_file;
chan_file->private_data = chan;
fd_install(chan_fd, chan_file);
return chan_fd;
chan_error:
atomic_long_dec(&session_file->f_count);
refcount_error:
fput(chan_file);
file_error:
put_unused_fd(chan_fd);
fd_error:
return ret;
}
/**
* lttng_session_ioctl - lttng session fd ioctl
*
* @file: the file
* @cmd: the command
* @arg: command arg
*
* This ioctl implements lttng commands:
* LTTNG_KERNEL_CHANNEL
* Returns a LTTng channel file descriptor
* LTTNG_KERNEL_ENABLE
* Enables tracing for a session (weak enable)
* LTTNG_KERNEL_DISABLE
* Disables tracing for a session (strong disable)
* LTTNG_KERNEL_METADATA
* Returns a LTTng metadata file descriptor
* LTTNG_KERNEL_SESSION_TRACK_PID
* Add PID to session tracker
* LTTNG_KERNEL_SESSION_UNTRACK_PID
* Remove PID from session tracker
*
* The returned channel will be deleted when its file descriptor is closed.
*/
static
long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
struct lttng_session *session = file->private_data;
switch (cmd) {
case LTTNG_KERNEL_OLD_CHANNEL:
{
struct lttng_kernel_channel chan_param;
struct lttng_kernel_old_channel old_chan_param;
if (copy_from_user(&old_chan_param,
(struct lttng_kernel_old_channel __user *) arg,
sizeof(struct lttng_kernel_old_channel)))
return -EFAULT;
chan_param.overwrite = old_chan_param.overwrite;
chan_param.subbuf_size = old_chan_param.subbuf_size;
chan_param.num_subbuf = old_chan_param.num_subbuf;
chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
chan_param.read_timer_interval = old_chan_param.read_timer_interval;
chan_param.output = old_chan_param.output;
return lttng_abi_create_channel(file, &chan_param,
PER_CPU_CHANNEL);
}
case LTTNG_KERNEL_CHANNEL:
{
struct lttng_kernel_channel chan_param;
if (copy_from_user(&chan_param,
(struct lttng_kernel_channel __user *) arg,
sizeof(struct lttng_kernel_channel)))
return -EFAULT;
return lttng_abi_create_channel(file, &chan_param,
PER_CPU_CHANNEL);
}
case LTTNG_KERNEL_OLD_SESSION_START:
case LTTNG_KERNEL_OLD_ENABLE:
case LTTNG_KERNEL_SESSION_START:
case LTTNG_KERNEL_ENABLE:
return lttng_session_enable(session);
case LTTNG_KERNEL_OLD_SESSION_STOP:
case LTTNG_KERNEL_OLD_DISABLE:
case LTTNG_KERNEL_SESSION_STOP:
case LTTNG_KERNEL_DISABLE:
return lttng_session_disable(session);
case LTTNG_KERNEL_OLD_METADATA:
{
struct lttng_kernel_channel chan_param;
struct lttng_kernel_old_channel old_chan_param;
if (copy_from_user(&old_chan_param,
(struct lttng_kernel_old_channel __user *) arg,
sizeof(struct lttng_kernel_old_channel)))
return -EFAULT;
chan_param.overwrite = old_chan_param.overwrite;
chan_param.subbuf_size = old_chan_param.subbuf_size;
chan_param.num_subbuf = old_chan_param.num_subbuf;
chan_param.switch_timer_interval = old_chan_param.switch_timer_interval;
chan_param.read_timer_interval = old_chan_param.read_timer_interval;
chan_param.output = old_chan_param.output;
return lttng_abi_create_channel(file, &chan_param,
METADATA_CHANNEL);
}
case LTTNG_KERNEL_METADATA:
{
struct lttng_kernel_channel chan_param;
if (copy_from_user(&chan_param,
(struct lttng_kernel_channel __user *) arg,
sizeof(struct lttng_kernel_channel)))
return -EFAULT;
return lttng_abi_create_channel(file, &chan_param,
METADATA_CHANNEL);
}
case LTTNG_KERNEL_SESSION_TRACK_PID:
return lttng_session_track_pid(session, (int) arg);
case LTTNG_KERNEL_SESSION_UNTRACK_PID:
return lttng_session_untrack_pid(session, (int) arg);
case LTTNG_KERNEL_SESSION_LIST_TRACKER_PIDS:
return lttng_session_list_tracker_pids(session);
case LTTNG_KERNEL_SESSION_METADATA_REGEN:
return lttng_session_metadata_regenerate(session);
case LTTNG_KERNEL_SESSION_STATEDUMP:
return lttng_session_statedump(session);
default:
return -ENOIOCTLCMD;
}
}
/*
* Called when the last file reference is dropped.
*
* Big fat note: channels and events are invariant for the whole session after
* their creation. So this session destruction also destroys all channel and
* event structures specific to this session (they are not destroyed when their
* individual file is released).
*/
static
int lttng_session_release(struct inode *inode, struct file *file)
{
struct lttng_session *session = file->private_data;
if (session)
lttng_session_destroy(session);
return 0;
}
static const struct file_operations lttng_session_fops = {
.owner = THIS_MODULE,
.release = lttng_session_release,
.unlocked_ioctl = lttng_session_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = lttng_session_ioctl,
#endif
};
/**
* lttng_metadata_ring_buffer_poll - LTTng ring buffer poll file operation
* @filp: the file
* @wait: poll table
*
* Handles the poll operations for the metadata channels.
*/
static
unsigned int lttng_metadata_ring_buffer_poll(struct file *filp,
poll_table *wait)
{
struct lttng_metadata_stream *stream = filp->private_data;
struct lib_ring_buffer *buf = stream->priv;
int finalized;
unsigned int mask = 0;
if (filp->f_mode & FMODE_READ) {
poll_wait_set_exclusive(wait);
poll_wait(filp, &stream->read_wait, wait);
finalized = stream->finalized;
/*
* lib_ring_buffer_is_finalized() contains a smp_rmb()
* ordering finalized load before offsets loads.
*/
WARN_ON(atomic_long_read(&buf->active_readers) != 1);
if (finalized)
mask |= POLLHUP;
mutex_lock(&stream->metadata_cache->lock);
if (stream->metadata_cache->metadata_written >
stream->metadata_out)
mask |= POLLIN;
mutex_unlock(&stream->metadata_cache->lock);
}
return mask;
}
static
void lttng_metadata_ring_buffer_ioctl_put_next_subbuf(struct file *filp,
unsigned int cmd, unsigned long arg)
{
struct lttng_metadata_stream *stream = filp->private_data;
stream->metadata_out = stream->metadata_in;
}
static
long lttng_metadata_ring_buffer_ioctl(struct file *filp,
unsigned int cmd, unsigned long arg)
{
int ret;
struct lttng_metadata_stream *stream = filp->private_data;
struct lib_ring_buffer *buf = stream->priv;
switch (cmd) {
case RING_BUFFER_GET_NEXT_SUBBUF:
{
struct lttng_metadata_stream *stream = filp->private_data;
struct lib_ring_buffer *buf = stream->priv;
struct channel *chan = buf->backend.chan;
ret = lttng_metadata_output_channel(stream, chan);
if (ret > 0) {
lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
ret = 0;
} else if (ret < 0)
goto err;
break;
}
case RING_BUFFER_GET_SUBBUF:
{
/*
* Random access is not allowed for metadata channel.
*/
return -ENOSYS;
}
case RING_BUFFER_FLUSH_EMPTY: /* Fall-through. */
case RING_BUFFER_FLUSH:
{
struct lttng_metadata_stream *stream = filp->private_data;
struct lib_ring_buffer *buf = stream->priv;
struct channel *chan = buf->backend.chan;
/*
* Before doing the actual ring buffer flush, write up to one
* packet of metadata in the ring buffer.
*/
ret = lttng_metadata_output_channel(stream, chan);
if (ret < 0)
goto err;
break;
}
case RING_BUFFER_GET_METADATA_VERSION:
{
struct lttng_metadata_stream *stream = filp->private_data;
return put_u64(stream->version, arg);
}
default:
break;
}
/* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
/* Performing lib ring buffer ioctl after our own. */
ret = lib_ring_buffer_ioctl(filp, cmd, arg, buf);
if (ret < 0)
goto err;
switch (cmd) {
case RING_BUFFER_PUT_NEXT_SUBBUF:
{
lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
cmd, arg);
break;
}
default:
break;
}
err:
return ret;
}
#ifdef CONFIG_COMPAT
static
long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
unsigned int cmd, unsigned long arg)
{
int ret;
struct lttng_metadata_stream *stream = filp->private_data;
struct lib_ring_buffer *buf = stream->priv;
switch (cmd) {
case RING_BUFFER_GET_NEXT_SUBBUF:
{
struct lttng_metadata_stream *stream = filp->private_data;
struct lib_ring_buffer *buf = stream->priv;
struct channel *chan = buf->backend.chan;
ret = lttng_metadata_output_channel(stream, chan);
if (ret > 0) {
lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
ret = 0;
} else if (ret < 0)
goto err;
break;
}
case RING_BUFFER_GET_SUBBUF:
{
/*
* Random access is not allowed for metadata channel.
*/
return -ENOSYS;
}
case RING_BUFFER_FLUSH_EMPTY: /* Fall-through. */
case RING_BUFFER_FLUSH:
{
struct lttng_metadata_stream *stream = filp->private_data;
struct lib_ring_buffer *buf = stream->priv;
struct channel *chan = buf->backend.chan;
/*
* Before doing the actual ring buffer flush, write up to one
* packet of metadata in the ring buffer.
*/
ret = lttng_metadata_output_channel(stream, chan);
if (ret < 0)
goto err;
break;
}
case RING_BUFFER_GET_METADATA_VERSION:
{
struct lttng_metadata_stream *stream = filp->private_data;
return put_u64(stream->version, arg);
}
default:
break;
}
/* PUT_SUBBUF is the one from lib ring buffer, unmodified. */
/* Performing lib ring buffer ioctl after our own. */
ret = lib_ring_buffer_compat_ioctl(filp, cmd, arg, buf);
if (ret < 0)
goto err;
switch (cmd) {
case RING_BUFFER_PUT_NEXT_SUBBUF:
{
lttng_metadata_ring_buffer_ioctl_put_next_subbuf(filp,
cmd, arg);
break;
}
default:
break;
}
err:
return ret;
}
#endif
/*
* This is not used by anonymous file descriptors. This code is left
* there if we ever want to implement an inode with open() operation.
*/
static
int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
{
struct lttng_metadata_stream *stream = inode->i_private;
struct lib_ring_buffer *buf = stream->priv;
file->private_data = buf;
/*
* Since life-time of metadata cache differs from that of
* session, we need to keep our own reference on the transport.
*/
if (!try_module_get(stream->transport->owner)) {
printk(KERN_WARNING "LTT : Can't lock transport module.\n");
return -EBUSY;
}
return lib_ring_buffer_open(inode, file, buf);
}
static
int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
{
struct lttng_metadata_stream *stream = file->private_data;
struct lib_ring_buffer *buf = stream->priv;
kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
module_put(stream->transport->owner);
return lib_ring_buffer_release(inode, file, buf);
}
static
ssize_t lttng_metadata_ring_buffer_splice_read(struct file *in, loff_t *ppos,
struct pipe_inode_info *pipe, size_t len,
unsigned int flags)
{
struct lttng_metadata_stream *stream = in->private_data;
struct lib_ring_buffer *buf = stream->priv;
return lib_ring_buffer_splice_read(in, ppos, pipe, len,
flags, buf);
}
static
int lttng_metadata_ring_buffer_mmap(struct file *filp,
struct vm_area_struct *vma)
{
struct lttng_metadata_stream *stream = filp->private_data;
struct lib_ring_buffer *buf = stream->priv;
return lib_ring_buffer_mmap(filp, vma, buf);
}
static
const struct file_operations lttng_metadata_ring_buffer_file_operations = {
.owner = THIS_MODULE,
.open = lttng_metadata_ring_buffer_open,
.release = lttng_metadata_ring_buffer_release,
.poll = lttng_metadata_ring_buffer_poll,
.splice_read = lttng_metadata_ring_buffer_splice_read,
.mmap = lttng_metadata_ring_buffer_mmap,
.unlocked_ioctl = lttng_metadata_ring_buffer_ioctl,
.llseek = vfs_lib_ring_buffer_no_llseek,
#ifdef CONFIG_COMPAT
.compat_ioctl = lttng_metadata_ring_buffer_compat_ioctl,
#endif
};
static
int lttng_abi_create_stream_fd(struct file *channel_file, void *stream_priv,
const struct file_operations *fops)
{
int stream_fd, ret;
struct file *stream_file;
stream_fd = lttng_get_unused_fd();
if (stream_fd < 0) {
ret = stream_fd;
goto fd_error;
}
stream_file = anon_inode_getfile("[lttng_stream]", fops,
stream_priv, O_RDWR);
if (IS_ERR(stream_file)) {
ret = PTR_ERR(stream_file);
goto file_error;
}
/*
* OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
* FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
* file descriptor, so we set FMODE_PREAD here.
*/
stream_file->f_mode |= FMODE_PREAD;
fd_install(stream_fd, stream_file);
/*
* The stream holds a reference to the channel within the generic ring
* buffer library, so no need to hold a refcount on the channel and
* session files here.
*/
return stream_fd;
file_error:
put_unused_fd(stream_fd);
fd_error:
return ret;
}
static
int lttng_abi_open_stream(struct file *channel_file)
{
struct lttng_channel *channel = channel_file->private_data;
struct lib_ring_buffer *buf;
int ret;
void *stream_priv;
buf = channel->ops->buffer_read_open(channel->chan);
if (!buf)
return -ENOENT;
stream_priv = buf;
ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
<tng_stream_ring_buffer_file_operations);
if (ret < 0)
goto fd_error;
return ret;
fd_error:
channel->ops->buffer_read_close(buf);
return ret;
}
static
int lttng_abi_open_metadata_stream(struct file *channel_file)
{
struct lttng_channel *channel = channel_file->private_data;
struct lttng_session *session = channel->session;
struct lib_ring_buffer *buf;
int ret;
struct lttng_metadata_stream *metadata_stream;
void *stream_priv;
buf = channel->ops->buffer_read_open(channel->chan);
if (!buf)
return -ENOENT;
metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
GFP_KERNEL);
if (!metadata_stream) {
ret = -ENOMEM;
goto nomem;
}
metadata_stream->metadata_cache = session->metadata_cache;
init_waitqueue_head(&metadata_stream->read_wait);
metadata_stream->priv = buf;
stream_priv = metadata_stream;
metadata_stream->transport = channel->transport;
/*
* Since life-time of metadata cache differs from that of
* session, we need to keep our own reference on the transport.
*/
if (!try_module_get(metadata_stream->transport->owner)) {
printk(KERN_WARNING "LTT : Can't lock transport module.\n");
ret = -EINVAL;
goto notransport;
}
if (!lttng_kref_get(&session->metadata_cache->refcount)) {
ret = -EOVERFLOW;
goto kref_error;
}
ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
<tng_metadata_ring_buffer_file_operations);
if (ret < 0)
goto fd_error;
list_add(&metadata_stream->list,
&session->metadata_cache->metadata_stream);
return ret;
fd_error:
kref_put(&session->metadata_cache->refcount, metadata_cache_destroy);
kref_error:
module_put(metadata_stream->transport->owner);
notransport:
kfree(metadata_stream);