blob: 37cccfa35f472f0b43b9aff9693f959dc8680f8a [file] [log] [blame]
/*
* ltt-debugfs-abi.c
*
* Copyright 2010 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
*
* LTTng debugfs ABI
*
* 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.
*
* Dual LGPL v2.1/GPL v2 license.
*/
#include <linux/module.h>
#include <linux/debugfs.h>
#include <linux/proc_fs.h>
#include <linux/anon_inodes.h>
#include <linux/file.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
#include "wrapper/vmalloc.h" /* for wrapper_vmalloc_sync_all() */
#include "wrapper/ringbuffer/vfs.h"
#include "wrapper/poll.h"
#include "ltt-debugfs-abi.h"
#include "ltt-events.h"
#include "ltt-tracer.h"
/*
* This is LTTng's own personal way to create a system call as an external
* module. We use ioctl() on /sys/kernel/debug/lttng.
*/
static struct dentry *lttng_dentry;
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;
/*
* Teardown management: opened file descriptors keep a refcount on the module,
* so it can only exit when all file descriptors are closed.
*/
enum channel_type {
PER_CPU_CHANNEL,
METADATA_CHANNEL,
};
static
int lttng_abi_create_session(void)
{
struct ltt_session *session;
struct file *session_file;
int session_fd, ret;
session = ltt_session_create();
if (!session)
return -ENOMEM;
session_fd = get_unused_fd();
if (session_fd < 0) {
ret = session_fd;
goto fd_error;
}
session_file = anon_inode_getfile("[lttng_session]",
&lttng_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:
ltt_session_destroy(session);
return ret;
}
static
int lttng_abi_tracepoint_list(void)
{
struct file *tracepoint_list_file;
int file_fd, ret;
file_fd = get_unused_fd();
if (file_fd < 0) {
ret = file_fd;
goto fd_error;
}
tracepoint_list_file = anon_inode_getfile("[lttng_session]",
&lttng_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);
if (file_fd < 0) {
ret = file_fd;
goto fd_error;
}
return file_fd;
open_error:
fput(tracepoint_list_file);
file_error:
put_unused_fd(file_fd);
fd_error:
return ret;
}
static
long lttng_abi_tracer_version(struct file *file,
struct lttng_kernel_tracer_version __user *uversion_param)
{
struct lttng_kernel_tracer_version v;
v.version = LTTNG_VERSION;
v.patchlevel = LTTNG_PATCHLEVEL;
v.sublevel = LTTNG_SUBLEVEL;
if (copy_to_user(uversion_param, &v, sizeof(v)))
return -EFAULT;
return 0;
}
static
long lttng_abi_add_context(struct file *file,
struct lttng_kernel_context __user *ucontext_param,
struct lttng_ctx **ctx, struct ltt_session *session)
{
struct lttng_kernel_context context_param;
if (session->been_active)
return -EPERM;
if (copy_from_user(&context_param, ucontext_param, sizeof(context_param)))
return -EFAULT;
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_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);
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
*
* 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_SESSION:
return lttng_abi_create_session();
case LTTNG_KERNEL_TRACER_VERSION:
return lttng_abi_tracer_version(file,
(struct lttng_kernel_tracer_version __user *) arg);
case LTTNG_KERNEL_TRACEPOINT_LIST:
return lttng_abi_tracepoint_list();
case LTTNG_KERNEL_WAIT_QUIESCENT:
synchronize_trace();
return 0;
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
};
/*
* We tolerate no failure in this function (if one happens, we print a dmesg
* error, but cannot return any error, because the channel information is
* invariant.
*/
static
void lttng_metadata_create_events(struct file *channel_file)
{
struct ltt_channel *channel = channel_file->private_data;
static struct lttng_kernel_event metadata_params = {
.instrumentation = LTTNG_KERNEL_TRACEPOINT,
.name = "lttng_metadata",
};
struct ltt_event *event;
/*
* We tolerate no failure path after event creation. It will stay
* invariant for the rest of the session.
*/
event = ltt_event_create(channel, &metadata_params, NULL, NULL);
if (!event) {
goto create_error;
}
return;
create_error:
WARN_ON(1);
return; /* not allowed to return error */
}
static
int lttng_abi_create_channel(struct file *session_file,
struct lttng_kernel_channel __user *uchan_param,
enum channel_type channel_type)
{
struct ltt_session *session = session_file->private_data;
const struct file_operations *fops = NULL;
const char *transport_name;
struct ltt_channel *chan;
struct file *chan_file;
struct lttng_kernel_channel chan_param;
int chan_fd;
int ret = 0;
if (copy_from_user(&chan_param, uchan_param, sizeof(chan_param)))
return -EFAULT;
chan_fd = get_unused_fd();
if (chan_fd < 0) {
ret = chan_fd;
goto fd_error;
}
switch (channel_type) {
case PER_CPU_CHANNEL:
fops = &lttng_channel_fops;
break;
case METADATA_CHANNEL:
fops = &lttng_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;
}
/*
* We tolerate no failure path after channel creation. It will stay
* invariant for the rest of the session.
*/
chan = ltt_channel_create(session, transport_name, NULL,
chan_param.subbuf_size,
chan_param.num_subbuf,
chan_param.switch_timer_interval,
chan_param.read_timer_interval);
if (!chan) {
ret = -EINVAL;
goto chan_error;
}
chan->file = chan_file;
chan_file->private_data = chan;
fd_install(chan_fd, chan_file);
if (channel_type == METADATA_CHANNEL) {
session->metadata = chan;
lttng_metadata_create_events(chan_file);
}
/* The channel created holds a reference on the session */
atomic_long_inc(&session_file->f_count);
return chan_fd;
chan_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
*
* 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 ltt_session *session = file->private_data;
switch (cmd) {
case LTTNG_KERNEL_CHANNEL:
return lttng_abi_create_channel(file,
(struct lttng_kernel_channel __user *) arg,
PER_CPU_CHANNEL);
case LTTNG_KERNEL_SESSION_START:
case LTTNG_KERNEL_ENABLE:
return ltt_session_enable(session);
case LTTNG_KERNEL_SESSION_STOP:
case LTTNG_KERNEL_DISABLE:
return ltt_session_disable(session);
case LTTNG_KERNEL_METADATA:
return lttng_abi_create_channel(file,
(struct lttng_kernel_channel __user *) arg,
METADATA_CHANNEL);
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 ltt_session *session = file->private_data;
if (session)
ltt_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
};
static
int lttng_abi_open_stream(struct file *channel_file)
{
struct ltt_channel *channel = channel_file->private_data;
struct lib_ring_buffer *buf;
int stream_fd, ret;
struct file *stream_file;
buf = channel->ops->buffer_read_open(channel->chan);
if (!buf)
return -ENOENT;
stream_fd = get_unused_fd();
if (stream_fd < 0) {
ret = stream_fd;
goto fd_error;
}
stream_file = anon_inode_getfile("[lttng_stream]",
&lib_ring_buffer_file_operations,
buf, 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:
channel->ops->buffer_read_close(buf);
return ret;
}
static
int lttng_abi_create_event(struct file *channel_file,
struct lttng_kernel_event __user *uevent_param)
{
struct ltt_channel *channel = channel_file->private_data;
struct ltt_event *event;
struct lttng_kernel_event event_param;
int event_fd, ret;
struct file *event_file;
if (copy_from_user(&event_param, uevent_param, sizeof(event_param)))
return -EFAULT;
event_param.name[LTTNG_SYM_NAME_LEN - 1] = '\0';
switch (event_param.instrumentation) {
case LTTNG_KERNEL_KRETPROBE:
event_param.u.kretprobe.symbol_name[LTTNG_SYM_NAME_LEN - 1] = '\0';
break;
case LTTNG_KERNEL_KPROBE:
event_param.u.kprobe.symbol_name[LTTNG_SYM_NAME_LEN - 1] = '\0';
break;
case LTTNG_KERNEL_FUNCTION:
event_param.u.ftrace.symbol_name[LTTNG_SYM_NAME_LEN - 1] = '\0';
break;
default:
break;
}
switch (event_param.instrumentation) {
default:
event_fd = get_unused_fd();
if (event_fd < 0) {
ret = event_fd;
goto fd_error;
}
event_file = anon_inode_getfile("[lttng_event]",
&lttng_event_fops,
NULL, O_RDWR);
if (IS_ERR(event_file)) {
ret = PTR_ERR(event_file);
goto file_error;
}
/*
* We tolerate no failure path after event creation. It
* will stay invariant for the rest of the session.
*/
event = ltt_event_create(channel, &event_param, NULL, NULL);
if (!event) {
ret = -EINVAL;
goto event_error;
}
event_file->private_data = event;
fd_install(event_fd, event_file);
/* The event holds a reference on the channel */
atomic_long_inc(&channel_file->f_count);
break;
case LTTNG_KERNEL_SYSCALL:
/*
* Only all-syscall tracing supported for now.
*/
if (event_param.name[0] != '\0')
return -EINVAL;
ret = lttng_syscalls_register(channel, NULL);
if (ret)
goto fd_error;
event_fd = 0;
break;
}
return event_fd;
event_error:
fput(event_file);
file_error:
put_unused_fd(event_fd);
fd_error:
return ret;
}
/**
* lttng_channel_ioctl - lttng syscall through ioctl
*
* @file: the file
* @cmd: the command
* @arg: command arg
*
* This ioctl implements lttng commands:
* LTTNG_KERNEL_STREAM
* Returns an event stream file descriptor or failure.
* (typically, one event stream records events from one CPU)
* LTTNG_KERNEL_EVENT
* Returns an event file descriptor or failure.
* LTTNG_KERNEL_CONTEXT
* Prepend a context field to each event in the channel
* LTTNG_KERNEL_ENABLE
* Enable recording for events in this channel (weak enable)
* LTTNG_KERNEL_DISABLE
* Disable recording for events in this channel (strong disable)
*
* Channel and event file descriptors also hold a reference on the session.
*/
static
long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
struct ltt_channel *channel = file->private_data;
switch (cmd) {
case LTTNG_KERNEL_STREAM:
return lttng_abi_open_stream(file);
case LTTNG_KERNEL_EVENT:
return lttng_abi_create_event(file, (struct lttng_kernel_event __user *) arg);
case LTTNG_KERNEL_CONTEXT:
return lttng_abi_add_context(file,
(struct lttng_kernel_context __user *) arg,
&channel->ctx, channel->session);
case LTTNG_KERNEL_ENABLE:
return ltt_channel_enable(channel);
case LTTNG_KERNEL_DISABLE:
return ltt_channel_disable(channel);
default:
return -ENOIOCTLCMD;
}
}
/**
* lttng_metadata_ioctl - lttng syscall through ioctl
*
* @file: the file
* @cmd: the command
* @arg: command arg
*
* This ioctl implements lttng commands:
* LTTNG_KERNEL_STREAM
* Returns an event stream file descriptor or failure.
*
* Channel and event file descriptors also hold a reference on the session.
*/
static
long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
switch (cmd) {
case LTTNG_KERNEL_STREAM:
return lttng_abi_open_stream(file);
default:
return -ENOIOCTLCMD;
}
}
/**
* lttng_channel_poll - lttng stream addition/removal monitoring
*
* @file: the file
* @wait: poll table
*/
unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
{
struct ltt_channel *channel = file->private_data;
unsigned int mask = 0;
if (file->f_mode & FMODE_READ) {
poll_wait_set_exclusive(wait);
poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
wait);
if (channel->ops->is_disabled(channel->chan))
return POLLERR;
if (channel->ops->is_finalized(channel->chan))
return POLLHUP;
if (channel->ops->buffer_has_read_closed_stream(channel->chan))
return POLLIN | POLLRDNORM;
return 0;
}
return mask;
}
static
int lttng_channel_release(struct inode *inode, struct file *file)
{
struct ltt_channel *channel = file->private_data;
if (channel)
fput(channel->session->file);
return 0;
}
static const struct file_operations lttng_channel_fops = {
.owner = THIS_MODULE,
.release = lttng_channel_release,
.poll = lttng_channel_poll,
.unlocked_ioctl = lttng_channel_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = lttng_channel_ioctl,
#endif
};
static const struct file_operations lttng_metadata_fops = {
.owner = THIS_MODULE,
.release = lttng_channel_release,
.unlocked_ioctl = lttng_metadata_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = lttng_metadata_ioctl,
#endif
};
/**
* lttng_event_ioctl - lttng syscall through ioctl
*
* @file: the file
* @cmd: the command
* @arg: command arg
*
* This ioctl implements lttng commands:
* LTTNG_KERNEL_CONTEXT
* Prepend a context field to each record of this event
* LTTNG_KERNEL_ENABLE
* Enable recording for this event (weak enable)
* LTTNG_KERNEL_DISABLE
* Disable recording for this event (strong disable)
*/
static
long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
struct ltt_event *event = file->private_data;
switch (cmd) {
case LTTNG_KERNEL_CONTEXT:
return lttng_abi_add_context(file,
(struct lttng_kernel_context __user *) arg,
&event->ctx, event->chan->session);
case LTTNG_KERNEL_ENABLE:
return ltt_event_enable(event);
case LTTNG_KERNEL_DISABLE:
return ltt_event_disable(event);
default:
return -ENOIOCTLCMD;
}
}
static
int lttng_event_release(struct inode *inode, struct file *file)
{
struct ltt_event *event = file->private_data;
if (event)
fput(event->chan->file);
return 0;
}
/* TODO: filter control ioctl */
static const struct file_operations lttng_event_fops = {
.owner = THIS_MODULE,
.release = lttng_event_release,
.unlocked_ioctl = lttng_event_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = lttng_event_ioctl,
#endif
};
int __init ltt_debugfs_abi_init(void)
{
int ret = 0;
wrapper_vmalloc_sync_all();
lttng_dentry = debugfs_create_file("lttng", S_IWUSR, NULL, NULL,
&lttng_fops);
if (IS_ERR(lttng_dentry))
lttng_dentry = NULL;
lttng_proc_dentry = proc_create_data("lttng", S_IWUSR, NULL,
&lttng_fops, NULL);
if (!lttng_dentry && !lttng_proc_dentry) {
printk(KERN_ERR "Error creating LTTng control file\n");
ret = -ENOMEM;
goto error;
}
error:
return ret;
}
void __exit ltt_debugfs_abi_exit(void)
{
if (lttng_dentry)
debugfs_remove(lttng_dentry);
if (lttng_proc_dentry)
remove_proc_entry("lttng", NULL);
}