[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 "wrapper/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_metadata_fops;
static const struct file_operations lttng_event_fops;

enum channel_type {
	PER_CPU_CHANNEL,
	GLOBAL_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;
}

/**
 *	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
};

/*
 * 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;
	char *event_name = "lttng-metadata";
	struct ltt_event *event;
	int ret;
	void *probe;

	probe = ltt_probe_get(event_name);
	if (!probe) {
		ret = -ENOENT;
		goto probe_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, INSTRUM_TRACEPOINTS,
				 probe, NULL);
	if (!event) {
		goto event_error;
		ret = -EEXIST;
	}
	return;

event_error:
	ltt_probe_put(probe);
probe_error:
	WARN_ON(1);
	return;		/* not allowed to return error */
}

static
int lttng_abi_create_channel(struct file *session_file,
			     struct lttng_channel __user *uchan_param,
			     enum channel_type channel_type)
{
	struct ltt_session *session = session_file->private_data;
	const struct file_operations *fops;
	const char *transport_name;
	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;
	}
	switch (channel_type) {
	case PER_CPU_CHANNEL:
		transport_name = chan_param.overwrite ?
			"relay-overwrite" : "relay-discard";
		fops = &lttng_channel_fops;
		break;
	case GLOBAL_CHANNEL:
		transport_name = chan_param.overwrite ?
			"global-relay-overwrite" : "global-relay-discard";
		fops = &lttng_channel_fops;
		break;
	case METADATA_CHANNEL:
		transport_name = "global-relay-discard";
		fops = &lttng_metadata_fops;
		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)
		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_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,
				PER_CPU_CHANNEL);
	case LTTNG_SESSION_START:
		return ltt_session_start(session);
	case LTTNG_SESSION_STOP:
		return ltt_session_stop(session);
	case LTTNG_METADATA:
		return lttng_abi_create_channel(file,
				(struct lttng_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 = {
	.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_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.
 *
 * 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;
	}
}

/**
 *	lttng_metadata_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.
 *
 * 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_STREAM:
		return lttng_abi_open_stream(file);
	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 const struct file_operations lttng_metadata_fops = {
	.release = lttng_channel_release,
	.unlocked_ioctl = lttng_metadata_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl = lttng_metadata_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>
f3bc08c5	31	#include "wrapper/ringbuffer/vfs.h"
11b5a3c2	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;
5dbbdb43	44	static const struct file_operations lttng_metadata_fops;
305d3e42	45	static const struct file_operations lttng_event_fops;
baf20995	46
5dbbdb43 MD	47	enum channel_type {
	48	PER_CPU_CHANNEL,
	49	GLOBAL_CHANNEL,
	50	METADATA_CHANNEL,
	51	};
	52
ad1c05e1	53	static
baf20995 MD	54	int lttng_abi_create_session(void)
	55	{
	56	struct ltt_session *session;
c0e31d2e	57	struct file *session_file;
11b5a3c2	58	int session_fd, ret;
baf20995	59
653fe716	60	session = ltt_session_create();
baf20995 MD	61	if (!session)
baf20995 MD	62	return -ENOMEM;
1c25284c	63	session_fd = get_unused_fd();
baf20995 MD	64	if (session_fd < 0) {
	65	ret = session_fd;
	66	goto fd_error;
	67	}
c0e31d2e	68	session_file = anon_inode_getfile("[lttng_session]",
ad1c05e1	69	&lttng_session_fops,
baf20995	70	session, O_RDWR);
c0e31d2e MD	71	if (IS_ERR(session_file)) {
c0e31d2e MD	72	ret = PTR_ERR(session_file);
baf20995 MD	73	goto file_error;
baf20995 MD	74	}
c0e31d2e MD	75	session->file = session_file;
c0e31d2e MD	76	fd_install(session_fd, session_file);
baf20995 MD	77	return session_fd;
	78
	79	file_error:
	80	put_unused_fd(session_fd);
	81	fd_error:
	82	ltt_session_destroy(session);
	83	return ret;
	84	}
	85
ad1c05e1 MD	86	/**
	87	* lttng_ioctl - lttng syscall through ioctl
	88	*
c0e31d2e	89	* @file: the file
ad1c05e1 MD	90	* @cmd: the command
	91	* @arg: command arg
	92	*
	93	* This ioctl implements lttng commands:
	94	* LTTNG_SESSION
	95	* Returns a LTTng trace session file descriptor
	96	*
	97	* The returned session will be deleted when its file descriptor is closed.
	98	*/
	99	static
c0e31d2e	100	long lttng_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
ad1c05e1 MD	101	{
	102	switch (cmd) {
	103	case LTTNG_SESSION:
	104	return lttng_abi_create_session();
	105	default:
	106	return -ENOIOCTLCMD;
	107	}
	108	}
	109
ad1c05e1 MD	110	static const struct file_operations lttng_fops = {
	111	.unlocked_ioctl = lttng_ioctl,
	112	#ifdef CONFIG_COMPAT
03037b98	113	.compat_ioctl = lttng_ioctl,
ad1c05e1	114	#endif
11b5a3c2	115	};
ad1c05e1	116
5dbbdb43 MD	117	/*
	118	* We tolerate no failure in this function (if one happens, we print a dmesg
	119	* error, but cannot return any error, because the channel information is
	120	* invariant.
	121	*/
	122	static
	123	void lttng_metadata_create_events(struct file *channel_file)
	124	{
	125	struct ltt_channel *channel = channel_file->private_data;
	126	char *event_name = "lttng-metadata";
	127	struct ltt_event *event;
	128	int ret;
	129	void *probe;
	130
	131	probe = ltt_probe_get(event_name);
	132	if (!probe) {
	133	ret = -ENOENT;
	134	goto probe_error;
	135	}
	136	/*
	137	* We tolerate no failure path after event creation. It will stay
	138	* invariant for the rest of the session.
	139	*/
	140	event = ltt_event_create(channel, event_name, INSTRUM_TRACEPOINTS,
	141	probe, NULL);
	142	if (!event) {
	143	goto event_error;
	144	ret = -EEXIST;
	145	}
	146	return;
	147
	148	event_error:
	149	ltt_probe_put(probe);
	150	probe_error:
	151	WARN_ON(1);
	152	return; /* not allowed to return error */
	153	}
	154
	155	static
c0e31d2e	156	int lttng_abi_create_channel(struct file *session_file,
5dbbdb43 MD	157	struct lttng_channel __user *uchan_param,
5dbbdb43 MD	158	enum channel_type channel_type)
baf20995	159	{
c0e31d2e	160	struct ltt_session *session = session_file->private_data;
5dbbdb43 MD	161	const struct file_operations *fops;
5dbbdb43 MD	162	const char *transport_name;
baf20995	163	struct ltt_channel *chan;
c0e31d2e	164	struct file *chan_file;
baf20995 MD	165	struct lttng_channel chan_param;
baf20995 MD	166	int chan_fd;
ad1c05e1	167	int ret = 0;
baf20995	168
653fe716	169	if (copy_from_user(&chan_param, uchan_param, sizeof(chan_param)))
baf20995	170	return -EFAULT;
1c25284c	171	chan_fd = get_unused_fd();
baf20995 MD	172	if (chan_fd < 0) {
	173	ret = chan_fd;
	174	goto fd_error;
	175	}
c0e31d2e	176	chan_file = anon_inode_getfile("[lttng_channel]",
ad1c05e1	177	&lttng_channel_fops,
03037b98	178	NULL, O_RDWR);
c0e31d2e MD	179	if (IS_ERR(chan_file)) {
c0e31d2e MD	180	ret = PTR_ERR(chan_file);
baf20995 MD	181	goto file_error;
baf20995 MD	182	}
5dbbdb43 MD	183	switch (channel_type) {
	184	case PER_CPU_CHANNEL:
	185	transport_name = chan_param.overwrite ?
	186	"relay-overwrite" : "relay-discard";
	187	fops = &lttng_channel_fops;
	188	break;
	189	case GLOBAL_CHANNEL:
	190	transport_name = chan_param.overwrite ?
	191	"global-relay-overwrite" : "global-relay-discard";
	192	fops = &lttng_channel_fops;
	193	break;
	194	case METADATA_CHANNEL:
	195	transport_name = "global-relay-discard";
	196	fops = &lttng_metadata_fops;
	197	break;
	198	default:
	199	transport_name = "<unknown>";
	200	break;
	201	}
03037b98 MD	202	/*
	203	* We tolerate no failure path after channel creation. It will stay
	204	* invariant for the rest of the session.
	205	*/
5dbbdb43	206	chan = ltt_channel_create(session, transport_name, NULL,
11b5a3c2 MD	207	chan_param.subbuf_size,
	208	chan_param.num_subbuf,
	209	chan_param.switch_timer_interval,
	210	chan_param.read_timer_interval);
03037b98	211	if (!chan) {
f3d01b96	212	ret = -EINVAL;
03037b98 MD	213	goto chan_error;
03037b98 MD	214	}
11b5a3c2	215	chan->file = chan_file;
c0e31d2e MD	216	chan_file->private_data = chan;
c0e31d2e MD	217	fd_install(chan_fd, chan_file);
5dbbdb43 MD	218	if (channel_type == METADATA_CHANNEL)
	219	lttng_metadata_create_events(chan_file);
	220
ad1c05e1	221	/* The channel created holds a reference on the session */
b0caa15a	222	atomic_long_inc(&session_file->f_count);
ad1c05e1	223
baf20995 MD	224	return chan_fd;
baf20995 MD	225
03037b98	226	chan_error:
c0e31d2e	227	fput(chan_file);
baf20995 MD	228	file_error:
	229	put_unused_fd(chan_fd);
	230	fd_error:
baf20995 MD	231	return ret;
	232	}
	233
	234	/**
ad1c05e1	235	* lttng_session_ioctl - lttng session fd ioctl
baf20995	236	*
c0e31d2e	237	* @file: the file
baf20995 MD	238	* @cmd: the command
	239	* @arg: command arg
	240	*
	241	* This ioctl implements lttng commands:
baf20995 MD	242	* LTTNG_CHANNEL
baf20995 MD	243	* Returns a LTTng channel file descriptor
ad1c05e1 MD	244	*
	245	* The returned channel will be deleted when its file descriptor is closed.
	246	*/
	247	static
c0e31d2e	248	long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
ad1c05e1	249	{
c0e31d2e MD	250	struct ltt_session *session = file->private_data;
c0e31d2e MD	251
ad1c05e1 MD	252	switch (cmd) {
ad1c05e1 MD	253	case LTTNG_CHANNEL:
5dbbdb43 MD	254	return lttng_abi_create_channel(file,
	255	(struct lttng_channel __user *)arg,
	256	PER_CPU_CHANNEL);
c0e31d2e MD	257	case LTTNG_SESSION_START:
	258	return ltt_session_start(session);
	259	case LTTNG_SESSION_STOP:
	260	return ltt_session_stop(session);
5dbbdb43 MD	261	case LTTNG_METADATA:
	262	return lttng_abi_create_channel(file,
	263	(struct lttng_channel __user *)arg,
	264	METADATA_CHANNEL);
ad1c05e1 MD	265	default:
	266	return -ENOIOCTLCMD;
	267	}
	268	}
	269
03037b98 MD	270	/*
	271	* Called when the last file reference is dropped.
	272	*
	273	* Big fat note: channels and events are invariant for the whole session after
	274	* their creation. So this session destruction also destroys all channel and
	275	* event structures specific to this session (they are not destroyed when their
	276	* individual file is released).
	277	*/
ad1c05e1	278	static
03037b98	279	int lttng_session_release(struct inode inode, struct file file)
ad1c05e1	280	{
03037b98	281	struct ltt_session *session = file->private_data;
c269fff4 MD	282
	283	if (session)
	284	ltt_session_destroy(session);
11b5a3c2	285	return 0;
ad1c05e1	286	}
ad1c05e1 MD	287
ad1c05e1 MD	288	static const struct file_operations lttng_session_fops = {
03037b98	289	.release = lttng_session_release,
ad1c05e1 MD	290	.unlocked_ioctl = lttng_session_ioctl,
ad1c05e1 MD	291	#ifdef CONFIG_COMPAT
03037b98	292	.compat_ioctl = lttng_session_ioctl,
ad1c05e1	293	#endif
11b5a3c2	294	};
ad1c05e1 MD	295
ad1c05e1 MD	296	static
c0e31d2e	297	int lttng_abi_open_stream(struct file *channel_file)
ad1c05e1	298	{
c0e31d2e	299	struct ltt_channel *channel = channel_file->private_data;
ad1c05e1 MD	300	struct lib_ring_buffer *buf;
ad1c05e1 MD	301	int stream_fd, ret;
11b5a3c2	302	struct file *stream_file;
ad1c05e1	303
11b5a3c2	304	buf = channel->ops->buffer_read_open(channel->chan);
ad1c05e1 MD	305	if (!buf)
	306	return -ENOENT;
	307
1c25284c	308	stream_fd = get_unused_fd();
ad1c05e1 MD	309	if (stream_fd < 0) {
	310	ret = stream_fd;
	311	goto fd_error;
	312	}
c0e31d2e	313	stream_file = anon_inode_getfile("[lttng_stream]",
7f57c73c	314	&lib_ring_buffer_file_operations,
ad1c05e1	315	buf, O_RDWR);
c0e31d2e MD	316	if (IS_ERR(stream_file)) {
c0e31d2e MD	317	ret = PTR_ERR(stream_file);
ad1c05e1 MD	318	goto file_error;
ad1c05e1 MD	319	}
409453cb MD	320	/*
	321	* OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
	322	* FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
	323	* file descriptor, so we set FMODE_PREAD here.
	324	*/
d7b6f197	325	stream_file->f_mode \|= FMODE_PREAD;
c0e31d2e	326	fd_install(stream_fd, stream_file);
dda6a249 MD	327	/*
	328	* The stream holds a reference to the channel within the generic ring
	329	* buffer library, so no need to hold a refcount on the channel and
	330	* session files here.
	331	*/
ad1c05e1 MD	332	return stream_fd;
	333
	334	file_error:
	335	put_unused_fd(stream_fd);
	336	fd_error:
11b5a3c2	337	channel->ops->buffer_read_close(buf);
ad1c05e1 MD	338	return ret;
	339	}
	340
653fe716	341	static
c0e31d2e	342	int lttng_abi_create_event(struct file *channel_file,
653fe716 MD	343	struct lttng_event __user *uevent_param)
653fe716 MD	344	{
c0e31d2e	345	struct ltt_channel *channel = channel_file->private_data;
653fe716 MD	346	struct ltt_event *event;
	347	char *event_name;
	348	struct lttng_event event_param;
	349	int event_fd, ret;
11b5a3c2	350	struct file *event_file;
dda6a249	351	void *probe;
653fe716 MD	352
	353	if (copy_from_user(&event_param, uevent_param, sizeof(event_param)))
	354	return -EFAULT;
	355	event_name = kmalloc(PATH_MAX, GFP_KERNEL);
	356	if (!event_name)
	357	return -ENOMEM;
981616e8	358	if (strncpy_from_user(event_name, uevent_param->name, PATH_MAX) < 0) {
653fe716 MD	359	ret = -EFAULT;
	360	goto name_error;
	361	}
	362	event_name[PATH_MAX - 1] = '\0';
dda6a249 MD	363
	364	probe = ltt_probe_get(event_name);
	365	if (!probe) {
	366	ret = -ENOENT;
	367	goto probe_error;
	368	}
1c25284c	369	event_fd = get_unused_fd();
653fe716 MD	370	if (event_fd < 0) {
	371	ret = event_fd;
	372	goto fd_error;
	373	}
c0e31d2e	374	event_file = anon_inode_getfile("[lttng_event]",
3b923e5b	375	&lttng_event_fops,
03037b98	376	NULL, O_RDWR);
c0e31d2e MD	377	if (IS_ERR(event_file)) {
c0e31d2e MD	378	ret = PTR_ERR(event_file);
653fe716 MD	379	goto file_error;
653fe716 MD	380	}
03037b98 MD	381	/*
	382	* We tolerate no failure path after event creation. It will stay
	383	* invariant for the rest of the session.
	384	*/
11b5a3c2	385	event = ltt_event_create(channel, event_name, event_param.itype,
dda6a249	386	probe, NULL);
03037b98 MD	387	if (!event) {
	388	goto event_error;
	389	ret = -EEXIST;
	390	}
c0e31d2e MD	391	event_file->private_data = event;
c0e31d2e MD	392	fd_install(event_fd, event_file);
653fe716	393	/* The event holds a reference on the channel */
b0caa15a	394	atomic_long_inc(&channel_file->f_count);
03037b98	395	kfree(event_name);
653fe716 MD	396	return event_fd;
653fe716 MD	397
03037b98	398	event_error:
c0e31d2e	399	fput(event_file);
653fe716 MD	400	file_error:
	401	put_unused_fd(event_fd);
	402	fd_error:
dda6a249 MD	403	ltt_probe_put(probe);
dda6a249 MD	404	probe_error:
653fe716 MD	405	name_error:
	406	kfree(event_name);
	407	return ret;
	408	}
ad1c05e1 MD	409
	410	/**
	411	* lttng_channel_ioctl - lttng syscall through ioctl
	412	*
c0e31d2e	413	* @file: the file
ad1c05e1 MD	414	* @cmd: the command
	415	* @arg: command arg
	416	*
	417	* This ioctl implements lttng commands:
	418	* LTTNG_STREAM
	419	* Returns an event stream file descriptor or failure.
	420	* (typically, one event stream records events from one CPU)
baf20995	421	* LTTNG_EVENT
ad1c05e1	422	* Returns an event file descriptor or failure.
baf20995	423	*
baf20995 MD	424	* Channel and event file descriptors also hold a reference on the session.
baf20995 MD	425	*/
ad1c05e1	426	static
c0e31d2e	427	long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
baf20995	428	{
baf20995	429	switch (cmd) {
ad1c05e1	430	case LTTNG_STREAM:
c0e31d2e	431	return lttng_abi_open_stream(file);
baf20995	432	case LTTNG_EVENT:
c0e31d2e	433	return lttng_abi_create_event(file, (struct lttng_event __user *)arg);
baf20995 MD	434	default:
	435	return -ENOIOCTLCMD;
	436	}
	437	}
	438
5dbbdb43 MD	439	/**
	440	* lttng_metadata_ioctl - lttng syscall through ioctl
	441	*
	442	* @file: the file
	443	* @cmd: the command
	444	* @arg: command arg
	445	*
	446	* This ioctl implements lttng commands:
	447	* LTTNG_STREAM
	448	* Returns an event stream file descriptor or failure.
	449	*
	450	* Channel and event file descriptors also hold a reference on the session.
	451	*/
	452	static
	453	long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	454	{
	455	switch (cmd) {
	456	case LTTNG_STREAM:
	457	return lttng_abi_open_stream(file);
	458	default:
	459	return -ENOIOCTLCMD;
	460	}
	461	}
	462
3b923e5b MD	463	/* TODO: poll */
3b923e5b MD	464	#if 0
653fe716 MD	465	/**
	466	* lttng_channel_poll - lttng stream addition/removal monitoring
	467	*
c0e31d2e	468	* @file: the file
653fe716 MD	469	* @wait: poll table
653fe716 MD	470	*/
c0e31d2e	471	unsigned int lttng_channel_poll(struct file file, poll_table wait)
653fe716	472	{
c0e31d2e	473	struct ltt_channel *channel = file->private_data;
653fe716 MD	474	unsigned int mask = 0;
653fe716 MD	475
c0e31d2e	476	if (file->f_mode & FMODE_READ) {
653fe716	477	poll_wait_set_exclusive(wait);
c0e31d2e	478	poll_wait(file, &channel->notify_wait, wait);
653fe716 MD	479
	480	/* TODO: identify when the channel is being finalized. */
	481	if (finalized)
	482	return POLLHUP;
	483	else
	484	return POLLIN \| POLLRDNORM;
	485	}
	486	return mask;
	487
	488	}
3b923e5b	489	#endif //0
653fe716	490
0a84a57f MD	491	static
	492	int lttng_channel_release(struct inode inode, struct file file)
	493	{
	494	struct ltt_channel *channel = file->private_data;
c269fff4 MD	495
	496	if (channel)
	497	fput(channel->session->file);
0a84a57f MD	498	return 0;
	499	}
	500
ad1c05e1	501	static const struct file_operations lttng_channel_fops = {
03037b98	502	.release = lttng_channel_release,
3b923e5b MD	503	/* TODO */
3b923e5b MD	504	#if 0
653fe716	505	.poll = lttng_channel_poll,
3b923e5b	506	#endif //0
ad1c05e1	507	.unlocked_ioctl = lttng_channel_ioctl,
baf20995	508	#ifdef CONFIG_COMPAT
03037b98	509	.compat_ioctl = lttng_channel_ioctl,
baf20995	510	#endif
11b5a3c2	511	};
baf20995	512
5dbbdb43 MD	513	static const struct file_operations lttng_metadata_fops = {
	514	.release = lttng_channel_release,
	515	.unlocked_ioctl = lttng_metadata_ioctl,
	516	#ifdef CONFIG_COMPAT
	517	.compat_ioctl = lttng_metadata_ioctl,
	518	#endif
	519	};
	520
0a84a57f MD	521	static
	522	int lttng_event_release(struct inode inode, struct file file)
	523	{
	524	struct ltt_event *event = file->private_data;
c269fff4 MD	525
	526	if (event)
	527	fput(event->chan->file);
0a84a57f MD	528	return 0;
	529	}
	530
3b923e5b	531	/* TODO: filter control ioctl */
0a84a57f MD	532	static const struct file_operations lttng_event_fops = {
0a84a57f MD	533	.release = lttng_event_release,
11b5a3c2	534	};
0a84a57f	535
1c25284c	536	int __init ltt_debugfs_abi_init(void)
baf20995 MD	537	{
	538	int ret = 0;
	539
11b5a3c2	540	lttng_dentry = debugfs_create_file("lttng", S_IWUSR, NULL, NULL,
f3d01b96	541	&lttng_fops);
11b5a3c2	542	if (IS_ERR(lttng_dentry) \|\| !lttng_dentry) {
baf20995 MD	543	printk(KERN_ERR "Error creating LTTng control file\n");
	544	ret = -ENOMEM;
	545	goto error;
	546	}
	547	error:
	548	return ret;
	549	}
	550
1c25284c	551	void __exit ltt_debugfs_abi_exit(void)
baf20995	552	{
11b5a3c2	553	debugfs_remove(lttng_dentry);
baf20995	554	}