[lttng-modules.git] / ltt-debugfs-abi.c

/*
 * 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.
 */

#include <linux/module.h>
#include <linux/debugfs.h>
#include <linux/anon_inodes.h>
#include <linux/file.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
#include <linux/ringbuffer/vfs.h>
#include "ltt-debugfs-abi.h"
#include "ltt-events.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 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_event_fops;

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;
}

/**
 *	lttng_ioctl - lttng syscall through ioctl
 *
 *	@file: the file
 *	@cmd: the command
 *	@arg: command arg
 *
 *	This ioctl implements lttng commands:
 *	LTTNG_SESSION
 *		Returns a LTTng trace session file descriptor
 *
 * 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_SESSION:
		return lttng_abi_create_session();
	default:
		return -ENOIOCTLCMD;
	}
}

static const struct file_operations lttng_fops = {
	.unlocked_ioctl = lttng_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl = lttng_ioctl,
#endif
};

int lttng_abi_create_channel(struct file *session_file,
			     struct lttng_channel __user *uchan_param)
{
	struct ltt_session *session = session_file->private_data;
	struct ltt_channel *chan;
	struct file *chan_file;
	struct lttng_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;
	}
	chan_file = anon_inode_getfile("[lttng_channel]",
				       &lttng_channel_fops,
				       NULL, O_RDWR);
	if (IS_ERR(chan_file)) {
		ret = PTR_ERR(chan_file);
		goto file_error;
	}
	/*
	 * We tolerate no failure path after channel creation. It will stay
	 * invariant for the rest of the session.
	 */
	chan = ltt_channel_create(session, chan_param.overwrite, 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);
	/* 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_CHANNEL
 *		Returns a LTTng channel 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_CHANNEL:
		return lttng_abi_create_channel(file, (struct lttng_channel __user *)arg);
	case LTTNG_SESSION_START:
		return ltt_session_start(session);
	case LTTNG_SESSION_STOP:
		return ltt_session_stop(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 ltt_session *session = file->private_data;

	if (session)
		ltt_session_destroy(session);
	return 0;
}

static const struct file_operations lttng_session_fops = {
	.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;
	}
	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_event __user *uevent_param)
{
	struct ltt_channel *channel = channel_file->private_data;
	struct ltt_event *event;
	char *event_name;
	struct lttng_event event_param;
	int event_fd, ret;
	struct file *event_file;
	void *probe;

	if (copy_from_user(&event_param, uevent_param, sizeof(event_param)))
		return -EFAULT;
	event_name = kmalloc(PATH_MAX, GFP_KERNEL);
	if (!event_name)
		return -ENOMEM;
	if (strncpy_from_user(event_name, uevent_param->name, PATH_MAX) < 0) {
		ret = -EFAULT;
		goto name_error;
	}
	event_name[PATH_MAX - 1] = '\0';

	probe = ltt_probe_get(event_name);
	if (!probe) {
		ret = -ENOENT;
		goto probe_error;
	}
	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_name, event_param.itype,
				 probe, NULL);
	if (!event) {
		goto event_error;
		ret = -EEXIST;
	}
	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);
	kfree(event_name);
	return event_fd;

event_error:
	fput(event_file);
file_error:
	put_unused_fd(event_fd);
fd_error:
	ltt_probe_put(probe);
probe_error:
name_error:
	kfree(event_name);
	return ret;
}

/**
 *	lttng_channel_ioctl - lttng syscall through ioctl
 *
 *	@file: the file
 *	@cmd: the command
 *	@arg: command arg
 *
 *	This ioctl implements lttng commands:
 *      LTTNG_STREAM
 *              Returns an event stream file descriptor or failure.
 *              (typically, one event stream records events from one CPU)
 *	LTTNG_EVENT
 *		Returns an event file descriptor or failure.
 *
 * The returned session will be deleted when its file descriptor is closed.
 * 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)
{
	switch (cmd) {
	case LTTNG_STREAM:
		return lttng_abi_open_stream(file);
	case LTTNG_EVENT:
		return lttng_abi_create_event(file, (struct lttng_event __user *)arg);
	default:
		return -ENOIOCTLCMD;
	}
}

/* TODO: poll */
#if 0
/**
 *	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->notify_wait, wait);

		/* TODO: identify when the channel is being finalized. */
		if (finalized)
			return POLLHUP;
		else
			return POLLIN | POLLRDNORM;
	}
	return mask;

}
#endif //0

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 = {
	.release = lttng_channel_release,
/* TODO */
#if 0
	.poll = lttng_channel_poll,
#endif //0
	.unlocked_ioctl = lttng_channel_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl = lttng_channel_ioctl,
#endif
};

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 = {
	.release = lttng_event_release,
};

int __init ltt_debugfs_abi_init(void)
{
	int ret = 0;

	lttng_dentry = debugfs_create_file("lttng", S_IWUSR, NULL, NULL,
					   &lttng_fops);
	if (IS_ERR(lttng_dentry) || !lttng_dentry) {
		printk(KERN_ERR "Error creating LTTng control file\n");
		ret = -ENOMEM;
		goto error;
	}
error:
	return ret;
}

void __exit ltt_debugfs_abi_exit(void)
{
	debugfs_remove(lttng_dentry);
}
Commit	Line	Data
baf20995 MD	1	/*
	2	* ltt-debugfs-abi.c
	3	*
	4	* Copyright 2010 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	5	*
	6	* LTTng debugfs ABI
	7	*
	8	* Mimic system calls for:
	9	* - session creation, returns a file descriptor or failure.
ad1c05e1 MD	10	* - channel creation, returns a file descriptor or failure.
	11	* - Operates on a session file descriptor
	12	* - Takes all channel options as parameters.
	13	* - stream get, returns a file descriptor or failure.
	14	* - Operates on a channel file descriptor.
	15	* - stream notifier get, returns a file descriptor or failure.
	16	* - Operates on a channel file descriptor.
	17	* - event creation, returns a file descriptor or failure.
	18	* - Operates on a channel file descriptor
	19	* - Takes an event name as parameter
	20	* - Takes an instrumentation source as parameter
	21	* - e.g. tracepoints, dynamic_probes...
	22	* - Takes instrumentation source specific arguments.
baf20995 MD	23	*/
baf20995 MD	24
11b5a3c2	25	#include <linux/module.h>
baf20995	26	#include <linux/debugfs.h>
11b5a3c2 MD	27	#include <linux/anon_inodes.h>
	28	#include <linux/file.h>
	29	#include <linux/uaccess.h>
	30	#include <linux/slab.h>
	31	#include <linux/ringbuffer/vfs.h>
	32	#include "ltt-debugfs-abi.h"
ad1c05e1	33	#include "ltt-events.h"
baf20995 MD	34
	35	/*
	36	* This is LTTng's own personal way to create a system call as an external
	37	* module. We use ioctl() on /sys/kernel/debug/lttng.
	38	*/
	39
	40	static struct dentry *lttng_dentry;
ad1c05e1 MD	41	static const struct file_operations lttng_fops;
	42	static const struct file_operations lttng_session_fops;
	43	static const struct file_operations lttng_channel_fops;
305d3e42	44	static const struct file_operations lttng_event_fops;
baf20995	45
ad1c05e1	46	static
baf20995 MD	47	int lttng_abi_create_session(void)
	48	{
	49	struct ltt_session *session;
c0e31d2e	50	struct file *session_file;
11b5a3c2	51	int session_fd, ret;
baf20995	52
653fe716	53	session = ltt_session_create();
baf20995 MD	54	if (!session)
baf20995 MD	55	return -ENOMEM;
1c25284c	56	session_fd = get_unused_fd();
baf20995 MD	57	if (session_fd < 0) {
	58	ret = session_fd;
	59	goto fd_error;
	60	}
c0e31d2e	61	session_file = anon_inode_getfile("[lttng_session]",
ad1c05e1	62	&lttng_session_fops,
baf20995	63	session, O_RDWR);
c0e31d2e MD	64	if (IS_ERR(session_file)) {
c0e31d2e MD	65	ret = PTR_ERR(session_file);
baf20995 MD	66	goto file_error;
baf20995 MD	67	}
c0e31d2e MD	68	session->file = session_file;
c0e31d2e MD	69	fd_install(session_fd, session_file);
baf20995 MD	70	return session_fd;
	71
	72	file_error:
	73	put_unused_fd(session_fd);
	74	fd_error:
	75	ltt_session_destroy(session);
	76	return ret;
	77	}
	78
ad1c05e1 MD	79	/**
	80	* lttng_ioctl - lttng syscall through ioctl
	81	*
c0e31d2e	82	* @file: the file
ad1c05e1 MD	83	* @cmd: the command
	84	* @arg: command arg
	85	*
	86	* This ioctl implements lttng commands:
	87	* LTTNG_SESSION
	88	* Returns a LTTng trace session file descriptor
	89	*
	90	* The returned session will be deleted when its file descriptor is closed.
	91	*/
	92	static
c0e31d2e	93	long lttng_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
ad1c05e1 MD	94	{
	95	switch (cmd) {
	96	case LTTNG_SESSION:
	97	return lttng_abi_create_session();
	98	default:
	99	return -ENOIOCTLCMD;
	100	}
	101	}
	102
ad1c05e1 MD	103	static const struct file_operations lttng_fops = {
	104	.unlocked_ioctl = lttng_ioctl,
	105	#ifdef CONFIG_COMPAT
03037b98	106	.compat_ioctl = lttng_ioctl,
ad1c05e1	107	#endif
11b5a3c2	108	};
ad1c05e1	109
c0e31d2e	110	int lttng_abi_create_channel(struct file *session_file,
ad1c05e1	111	struct lttng_channel __user *uchan_param)
baf20995	112	{
c0e31d2e	113	struct ltt_session *session = session_file->private_data;
baf20995	114	struct ltt_channel *chan;
c0e31d2e	115	struct file *chan_file;
baf20995 MD	116	struct lttng_channel chan_param;
baf20995 MD	117	int chan_fd;
ad1c05e1	118	int ret = 0;
baf20995	119
653fe716	120	if (copy_from_user(&chan_param, uchan_param, sizeof(chan_param)))
baf20995	121	return -EFAULT;
1c25284c	122	chan_fd = get_unused_fd();
baf20995 MD	123	if (chan_fd < 0) {
	124	ret = chan_fd;
	125	goto fd_error;
	126	}
c0e31d2e	127	chan_file = anon_inode_getfile("[lttng_channel]",
ad1c05e1	128	&lttng_channel_fops,
03037b98	129	NULL, O_RDWR);
c0e31d2e MD	130	if (IS_ERR(chan_file)) {
c0e31d2e MD	131	ret = PTR_ERR(chan_file);
baf20995 MD	132	goto file_error;
baf20995 MD	133	}
03037b98 MD	134	/*
	135	* We tolerate no failure path after channel creation. It will stay
	136	* invariant for the rest of the session.
	137	*/
11b5a3c2 MD	138	chan = ltt_channel_create(session, chan_param.overwrite, NULL,
	139	chan_param.subbuf_size,
	140	chan_param.num_subbuf,
	141	chan_param.switch_timer_interval,
	142	chan_param.read_timer_interval);
03037b98	143	if (!chan) {
f3d01b96	144	ret = -EINVAL;
03037b98 MD	145	goto chan_error;
03037b98 MD	146	}
11b5a3c2	147	chan->file = chan_file;
c0e31d2e MD	148	chan_file->private_data = chan;
c0e31d2e MD	149	fd_install(chan_fd, chan_file);
ad1c05e1	150	/* The channel created holds a reference on the session */
b0caa15a	151	atomic_long_inc(&session_file->f_count);
ad1c05e1	152
baf20995 MD	153	return chan_fd;
baf20995 MD	154
03037b98	155	chan_error:
c0e31d2e	156	fput(chan_file);
baf20995 MD	157	file_error:
	158	put_unused_fd(chan_fd);
	159	fd_error:
baf20995 MD	160	return ret;
	161	}
	162
	163	/**
ad1c05e1	164	* lttng_session_ioctl - lttng session fd ioctl
baf20995	165	*
c0e31d2e	166	* @file: the file
baf20995 MD	167	* @cmd: the command
	168	* @arg: command arg
	169	*
	170	* This ioctl implements lttng commands:
baf20995 MD	171	* LTTNG_CHANNEL
baf20995 MD	172	* Returns a LTTng channel file descriptor
ad1c05e1 MD	173	*
	174	* The returned channel will be deleted when its file descriptor is closed.
	175	*/
	176	static
c0e31d2e	177	long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
ad1c05e1	178	{
c0e31d2e MD	179	struct ltt_session *session = file->private_data;
c0e31d2e MD	180
ad1c05e1 MD	181	switch (cmd) {
ad1c05e1 MD	182	case LTTNG_CHANNEL:
c0e31d2e MD	183	return lttng_abi_create_channel(file, (struct lttng_channel __user *)arg);
	184	case LTTNG_SESSION_START:
	185	return ltt_session_start(session);
	186	case LTTNG_SESSION_STOP:
	187	return ltt_session_stop(session);
ad1c05e1 MD	188	default:
	189	return -ENOIOCTLCMD;
	190	}
	191	}
	192
03037b98 MD	193	/*
	194	* Called when the last file reference is dropped.
	195	*
	196	* Big fat note: channels and events are invariant for the whole session after
	197	* their creation. So this session destruction also destroys all channel and
	198	* event structures specific to this session (they are not destroyed when their
	199	* individual file is released).
	200	*/
ad1c05e1	201	static
03037b98	202	int lttng_session_release(struct inode inode, struct file file)
ad1c05e1	203	{
03037b98	204	struct ltt_session *session = file->private_data;
c269fff4 MD	205
	206	if (session)
	207	ltt_session_destroy(session);
11b5a3c2	208	return 0;
ad1c05e1	209	}
ad1c05e1 MD	210
ad1c05e1 MD	211	static const struct file_operations lttng_session_fops = {
03037b98	212	.release = lttng_session_release,
ad1c05e1 MD	213	.unlocked_ioctl = lttng_session_ioctl,
ad1c05e1 MD	214	#ifdef CONFIG_COMPAT
03037b98	215	.compat_ioctl = lttng_session_ioctl,
ad1c05e1	216	#endif
11b5a3c2	217	};
ad1c05e1 MD	218
ad1c05e1 MD	219	static
c0e31d2e	220	int lttng_abi_open_stream(struct file *channel_file)
ad1c05e1	221	{
c0e31d2e	222	struct ltt_channel *channel = channel_file->private_data;
ad1c05e1 MD	223	struct lib_ring_buffer *buf;
ad1c05e1 MD	224	int stream_fd, ret;
11b5a3c2	225	struct file *stream_file;
ad1c05e1	226
11b5a3c2	227	buf = channel->ops->buffer_read_open(channel->chan);
ad1c05e1 MD	228	if (!buf)
	229	return -ENOENT;
	230
1c25284c	231	stream_fd = get_unused_fd();
ad1c05e1 MD	232	if (stream_fd < 0) {
	233	ret = stream_fd;
	234	goto fd_error;
	235	}
c0e31d2e	236	stream_file = anon_inode_getfile("[lttng_stream]",
7f57c73c	237	&lib_ring_buffer_file_operations,
ad1c05e1	238	buf, O_RDWR);
c0e31d2e MD	239	if (IS_ERR(stream_file)) {
c0e31d2e MD	240	ret = PTR_ERR(stream_file);
ad1c05e1 MD	241	goto file_error;
ad1c05e1 MD	242	}
c0e31d2e	243	fd_install(stream_fd, stream_file);
dda6a249 MD	244	/*
	245	* The stream holds a reference to the channel within the generic ring
	246	* buffer library, so no need to hold a refcount on the channel and
	247	* session files here.
	248	*/
ad1c05e1 MD	249	return stream_fd;
	250
	251	file_error:
	252	put_unused_fd(stream_fd);
	253	fd_error:
11b5a3c2	254	channel->ops->buffer_read_close(buf);
ad1c05e1 MD	255	return ret;
	256	}
	257
653fe716	258	static
c0e31d2e	259	int lttng_abi_create_event(struct file *channel_file,
653fe716 MD	260	struct lttng_event __user *uevent_param)
653fe716 MD	261	{
c0e31d2e	262	struct ltt_channel *channel = channel_file->private_data;
653fe716 MD	263	struct ltt_event *event;
	264	char *event_name;
	265	struct lttng_event event_param;
	266	int event_fd, ret;
11b5a3c2	267	struct file *event_file;
dda6a249	268	void *probe;
653fe716 MD	269
	270	if (copy_from_user(&event_param, uevent_param, sizeof(event_param)))
	271	return -EFAULT;
	272	event_name = kmalloc(PATH_MAX, GFP_KERNEL);
	273	if (!event_name)
	274	return -ENOMEM;
981616e8	275	if (strncpy_from_user(event_name, uevent_param->name, PATH_MAX) < 0) {
653fe716 MD	276	ret = -EFAULT;
	277	goto name_error;
	278	}
	279	event_name[PATH_MAX - 1] = '\0';
dda6a249 MD	280
	281	probe = ltt_probe_get(event_name);
	282	if (!probe) {
	283	ret = -ENOENT;
	284	goto probe_error;
	285	}
1c25284c	286	event_fd = get_unused_fd();
653fe716 MD	287	if (event_fd < 0) {
	288	ret = event_fd;
	289	goto fd_error;
	290	}
c0e31d2e	291	event_file = anon_inode_getfile("[lttng_event]",
3b923e5b	292	&lttng_event_fops,
03037b98	293	NULL, O_RDWR);
c0e31d2e MD	294	if (IS_ERR(event_file)) {
c0e31d2e MD	295	ret = PTR_ERR(event_file);
653fe716 MD	296	goto file_error;
653fe716 MD	297	}
03037b98 MD	298	/*
	299	* We tolerate no failure path after event creation. It will stay
	300	* invariant for the rest of the session.
	301	*/
11b5a3c2	302	event = ltt_event_create(channel, event_name, event_param.itype,
dda6a249	303	probe, NULL);
03037b98 MD	304	if (!event) {
	305	goto event_error;
	306	ret = -EEXIST;
	307	}
c0e31d2e MD	308	event_file->private_data = event;
c0e31d2e MD	309	fd_install(event_fd, event_file);
653fe716	310	/* The event holds a reference on the channel */
b0caa15a	311	atomic_long_inc(&channel_file->f_count);
03037b98	312	kfree(event_name);
653fe716 MD	313	return event_fd;
653fe716 MD	314
03037b98	315	event_error:
c0e31d2e	316	fput(event_file);
653fe716 MD	317	file_error:
	318	put_unused_fd(event_fd);
	319	fd_error:
dda6a249 MD	320	ltt_probe_put(probe);
dda6a249 MD	321	probe_error:
653fe716 MD	322	name_error:
	323	kfree(event_name);
	324	return ret;
	325	}
ad1c05e1 MD	326
	327	/**
	328	* lttng_channel_ioctl - lttng syscall through ioctl
	329	*
c0e31d2e	330	* @file: the file
ad1c05e1 MD	331	* @cmd: the command
	332	* @arg: command arg
	333	*
	334	* This ioctl implements lttng commands:
	335	* LTTNG_STREAM
	336	* Returns an event stream file descriptor or failure.
	337	* (typically, one event stream records events from one CPU)
baf20995	338	* LTTNG_EVENT
ad1c05e1	339	* Returns an event file descriptor or failure.
baf20995 MD	340	*
	341	* The returned session will be deleted when its file descriptor is closed.
	342	* Channel and event file descriptors also hold a reference on the session.
	343	*/
ad1c05e1	344	static
c0e31d2e	345	long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
baf20995	346	{
baf20995	347	switch (cmd) {
ad1c05e1	348	case LTTNG_STREAM:
c0e31d2e	349	return lttng_abi_open_stream(file);
baf20995	350	case LTTNG_EVENT:
c0e31d2e	351	return lttng_abi_create_event(file, (struct lttng_event __user *)arg);
baf20995 MD	352	default:
	353	return -ENOIOCTLCMD;
	354	}
	355	}
	356
3b923e5b MD	357	/* TODO: poll */
3b923e5b MD	358	#if 0
653fe716 MD	359	/**
	360	* lttng_channel_poll - lttng stream addition/removal monitoring
	361	*
c0e31d2e	362	* @file: the file
653fe716 MD	363	* @wait: poll table
653fe716 MD	364	*/
c0e31d2e	365	unsigned int lttng_channel_poll(struct file file, poll_table wait)
653fe716	366	{
c0e31d2e	367	struct ltt_channel *channel = file->private_data;
653fe716 MD	368	unsigned int mask = 0;
653fe716 MD	369
c0e31d2e	370	if (file->f_mode & FMODE_READ) {
653fe716	371	poll_wait_set_exclusive(wait);
c0e31d2e	372	poll_wait(file, &channel->notify_wait, wait);
653fe716 MD	373
	374	/* TODO: identify when the channel is being finalized. */
	375	if (finalized)
	376	return POLLHUP;
	377	else
	378	return POLLIN \| POLLRDNORM;
	379	}
	380	return mask;
	381
	382	}
3b923e5b	383	#endif //0
653fe716	384
0a84a57f MD	385	static
	386	int lttng_channel_release(struct inode inode, struct file file)
	387	{
	388	struct ltt_channel *channel = file->private_data;
c269fff4 MD	389
	390	if (channel)
	391	fput(channel->session->file);
0a84a57f MD	392	return 0;
	393	}
	394
ad1c05e1	395	static const struct file_operations lttng_channel_fops = {
03037b98	396	.release = lttng_channel_release,
3b923e5b MD	397	/* TODO */
3b923e5b MD	398	#if 0
653fe716	399	.poll = lttng_channel_poll,
3b923e5b	400	#endif //0
ad1c05e1	401	.unlocked_ioctl = lttng_channel_ioctl,
baf20995	402	#ifdef CONFIG_COMPAT
03037b98	403	.compat_ioctl = lttng_channel_ioctl,
baf20995	404	#endif
11b5a3c2	405	};
baf20995	406
0a84a57f MD	407	static
	408	int lttng_event_release(struct inode inode, struct file file)
	409	{
	410	struct ltt_event *event = file->private_data;
c269fff4 MD	411
	412	if (event)
	413	fput(event->chan->file);
0a84a57f MD	414	return 0;
	415	}
	416
3b923e5b	417	/* TODO: filter control ioctl */
0a84a57f MD	418	static const struct file_operations lttng_event_fops = {
0a84a57f MD	419	.release = lttng_event_release,
11b5a3c2	420	};
0a84a57f	421
1c25284c	422	int __init ltt_debugfs_abi_init(void)
baf20995 MD	423	{
	424	int ret = 0;
	425
11b5a3c2	426	lttng_dentry = debugfs_create_file("lttng", S_IWUSR, NULL, NULL,
f3d01b96	427	&lttng_fops);
11b5a3c2	428	if (IS_ERR(lttng_dentry) \|\| !lttng_dentry) {
baf20995 MD	429	printk(KERN_ERR "Error creating LTTng control file\n");
	430	ret = -ENOMEM;
	431	goto error;
	432	}
	433	error:
	434	return ret;
	435	}
	436
1c25284c	437	void __exit ltt_debugfs_abi_exit(void)
baf20995	438	{
11b5a3c2	439	debugfs_remove(lttng_dentry);
baf20995	440	}