[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/vmalloc.h>	/* For vmalloc_sync_all */
#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;

	vmalloc_sync_all();
	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>
a509e133	31	#include <linux/vmalloc.h> /* For vmalloc_sync_all */
f3bc08c5	32	#include "wrapper/ringbuffer/vfs.h"
11b5a3c2	33	#include "ltt-debugfs-abi.h"
ad1c05e1	34	#include "ltt-events.h"
baf20995 MD	35
	36	/*
	37	* This is LTTng's own personal way to create a system call as an external
	38	* module. We use ioctl() on /sys/kernel/debug/lttng.
	39	*/
	40
	41	static struct dentry *lttng_dentry;
ad1c05e1 MD	42	static const struct file_operations lttng_fops;
	43	static const struct file_operations lttng_session_fops;
	44	static const struct file_operations lttng_channel_fops;
5dbbdb43	45	static const struct file_operations lttng_metadata_fops;
305d3e42	46	static const struct file_operations lttng_event_fops;
baf20995	47
5dbbdb43 MD	48	enum channel_type {
	49	PER_CPU_CHANNEL,
	50	GLOBAL_CHANNEL,
	51	METADATA_CHANNEL,
	52	};
	53
ad1c05e1	54	static
baf20995 MD	55	int lttng_abi_create_session(void)
	56	{
	57	struct ltt_session *session;
c0e31d2e	58	struct file *session_file;
11b5a3c2	59	int session_fd, ret;
baf20995	60
653fe716	61	session = ltt_session_create();
baf20995 MD	62	if (!session)
baf20995 MD	63	return -ENOMEM;
1c25284c	64	session_fd = get_unused_fd();
baf20995 MD	65	if (session_fd < 0) {
	66	ret = session_fd;
	67	goto fd_error;
	68	}
c0e31d2e	69	session_file = anon_inode_getfile("[lttng_session]",
ad1c05e1	70	&lttng_session_fops,
baf20995	71	session, O_RDWR);
c0e31d2e MD	72	if (IS_ERR(session_file)) {
c0e31d2e MD	73	ret = PTR_ERR(session_file);
baf20995 MD	74	goto file_error;
baf20995 MD	75	}
c0e31d2e MD	76	session->file = session_file;
c0e31d2e MD	77	fd_install(session_fd, session_file);
baf20995 MD	78	return session_fd;
	79
	80	file_error:
	81	put_unused_fd(session_fd);
	82	fd_error:
	83	ltt_session_destroy(session);
	84	return ret;
	85	}
	86
ad1c05e1 MD	87	/**
	88	* lttng_ioctl - lttng syscall through ioctl
	89	*
c0e31d2e	90	* @file: the file
ad1c05e1 MD	91	* @cmd: the command
	92	* @arg: command arg
	93	*
	94	* This ioctl implements lttng commands:
	95	* LTTNG_SESSION
	96	* Returns a LTTng trace session file descriptor
	97	*
	98	* The returned session will be deleted when its file descriptor is closed.
	99	*/
	100	static
c0e31d2e	101	long lttng_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
ad1c05e1 MD	102	{
	103	switch (cmd) {
	104	case LTTNG_SESSION:
	105	return lttng_abi_create_session();
	106	default:
	107	return -ENOIOCTLCMD;
	108	}
	109	}
	110
ad1c05e1 MD	111	static const struct file_operations lttng_fops = {
	112	.unlocked_ioctl = lttng_ioctl,
	113	#ifdef CONFIG_COMPAT
03037b98	114	.compat_ioctl = lttng_ioctl,
ad1c05e1	115	#endif
11b5a3c2	116	};
ad1c05e1	117
5dbbdb43 MD	118	/*
	119	* We tolerate no failure in this function (if one happens, we print a dmesg
	120	* error, but cannot return any error, because the channel information is
	121	* invariant.
	122	*/
	123	static
	124	void lttng_metadata_create_events(struct file *channel_file)
	125	{
	126	struct ltt_channel *channel = channel_file->private_data;
	127	char *event_name = "lttng-metadata";
	128	struct ltt_event *event;
	129	int ret;
	130	void *probe;
	131
	132	probe = ltt_probe_get(event_name);
	133	if (!probe) {
	134	ret = -ENOENT;
	135	goto probe_error;
	136	}
	137	/*
	138	* We tolerate no failure path after event creation. It will stay
	139	* invariant for the rest of the session.
	140	*/
	141	event = ltt_event_create(channel, event_name, INSTRUM_TRACEPOINTS,
	142	probe, NULL);
	143	if (!event) {
	144	goto event_error;
	145	ret = -EEXIST;
	146	}
	147	return;
	148
	149	event_error:
	150	ltt_probe_put(probe);
	151	probe_error:
	152	WARN_ON(1);
	153	return; /* not allowed to return error */
	154	}
	155
	156	static
c0e31d2e	157	int lttng_abi_create_channel(struct file *session_file,
5dbbdb43 MD	158	struct lttng_channel __user *uchan_param,
5dbbdb43 MD	159	enum channel_type channel_type)
baf20995	160	{
c0e31d2e	161	struct ltt_session *session = session_file->private_data;
5dbbdb43 MD	162	const struct file_operations *fops;
5dbbdb43 MD	163	const char *transport_name;
baf20995	164	struct ltt_channel *chan;
c0e31d2e	165	struct file *chan_file;
baf20995 MD	166	struct lttng_channel chan_param;
baf20995 MD	167	int chan_fd;
ad1c05e1	168	int ret = 0;
baf20995	169
653fe716	170	if (copy_from_user(&chan_param, uchan_param, sizeof(chan_param)))
baf20995	171	return -EFAULT;
1c25284c	172	chan_fd = get_unused_fd();
baf20995 MD	173	if (chan_fd < 0) {
	174	ret = chan_fd;
	175	goto fd_error;
	176	}
c0e31d2e	177	chan_file = anon_inode_getfile("[lttng_channel]",
ad1c05e1	178	&lttng_channel_fops,
03037b98	179	NULL, O_RDWR);
c0e31d2e MD	180	if (IS_ERR(chan_file)) {
c0e31d2e MD	181	ret = PTR_ERR(chan_file);
baf20995 MD	182	goto file_error;
baf20995 MD	183	}
5dbbdb43 MD	184	switch (channel_type) {
	185	case PER_CPU_CHANNEL:
	186	transport_name = chan_param.overwrite ?
	187	"relay-overwrite" : "relay-discard";
	188	fops = &lttng_channel_fops;
	189	break;
	190	case GLOBAL_CHANNEL:
	191	transport_name = chan_param.overwrite ?
	192	"global-relay-overwrite" : "global-relay-discard";
	193	fops = &lttng_channel_fops;
	194	break;
	195	case METADATA_CHANNEL:
	196	transport_name = "global-relay-discard";
	197	fops = &lttng_metadata_fops;
	198	break;
	199	default:
	200	transport_name = "<unknown>";
	201	break;
	202	}
03037b98 MD	203	/*
	204	* We tolerate no failure path after channel creation. It will stay
	205	* invariant for the rest of the session.
	206	*/
5dbbdb43	207	chan = ltt_channel_create(session, transport_name, NULL,
11b5a3c2 MD	208	chan_param.subbuf_size,
	209	chan_param.num_subbuf,
	210	chan_param.switch_timer_interval,
	211	chan_param.read_timer_interval);
03037b98	212	if (!chan) {
f3d01b96	213	ret = -EINVAL;
03037b98 MD	214	goto chan_error;
03037b98 MD	215	}
11b5a3c2	216	chan->file = chan_file;
c0e31d2e MD	217	chan_file->private_data = chan;
c0e31d2e MD	218	fd_install(chan_fd, chan_file);
5dbbdb43 MD	219	if (channel_type == METADATA_CHANNEL)
	220	lttng_metadata_create_events(chan_file);
	221
ad1c05e1	222	/* The channel created holds a reference on the session */
b0caa15a	223	atomic_long_inc(&session_file->f_count);
ad1c05e1	224
baf20995 MD	225	return chan_fd;
baf20995 MD	226
03037b98	227	chan_error:
c0e31d2e	228	fput(chan_file);
baf20995 MD	229	file_error:
	230	put_unused_fd(chan_fd);
	231	fd_error:
baf20995 MD	232	return ret;
	233	}
	234
	235	/**
ad1c05e1	236	* lttng_session_ioctl - lttng session fd ioctl
baf20995	237	*
c0e31d2e	238	* @file: the file
baf20995 MD	239	* @cmd: the command
	240	* @arg: command arg
	241	*
	242	* This ioctl implements lttng commands:
baf20995 MD	243	* LTTNG_CHANNEL
baf20995 MD	244	* Returns a LTTng channel file descriptor
ad1c05e1 MD	245	*
	246	* The returned channel will be deleted when its file descriptor is closed.
	247	*/
	248	static
c0e31d2e	249	long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
ad1c05e1	250	{
c0e31d2e MD	251	struct ltt_session *session = file->private_data;
c0e31d2e MD	252
ad1c05e1 MD	253	switch (cmd) {
ad1c05e1 MD	254	case LTTNG_CHANNEL:
5dbbdb43 MD	255	return lttng_abi_create_channel(file,
	256	(struct lttng_channel __user *)arg,
	257	PER_CPU_CHANNEL);
c0e31d2e MD	258	case LTTNG_SESSION_START:
	259	return ltt_session_start(session);
	260	case LTTNG_SESSION_STOP:
	261	return ltt_session_stop(session);
5dbbdb43 MD	262	case LTTNG_METADATA:
	263	return lttng_abi_create_channel(file,
	264	(struct lttng_channel __user *)arg,
	265	METADATA_CHANNEL);
ad1c05e1 MD	266	default:
	267	return -ENOIOCTLCMD;
	268	}
	269	}
	270
03037b98 MD	271	/*
	272	* Called when the last file reference is dropped.
	273	*
	274	* Big fat note: channels and events are invariant for the whole session after
	275	* their creation. So this session destruction also destroys all channel and
	276	* event structures specific to this session (they are not destroyed when their
	277	* individual file is released).
	278	*/
ad1c05e1	279	static
03037b98	280	int lttng_session_release(struct inode inode, struct file file)
ad1c05e1	281	{
03037b98	282	struct ltt_session *session = file->private_data;
c269fff4 MD	283
	284	if (session)
	285	ltt_session_destroy(session);
11b5a3c2	286	return 0;
ad1c05e1	287	}
ad1c05e1 MD	288
ad1c05e1 MD	289	static const struct file_operations lttng_session_fops = {
03037b98	290	.release = lttng_session_release,
ad1c05e1 MD	291	.unlocked_ioctl = lttng_session_ioctl,
ad1c05e1 MD	292	#ifdef CONFIG_COMPAT
03037b98	293	.compat_ioctl = lttng_session_ioctl,
ad1c05e1	294	#endif
11b5a3c2	295	};
ad1c05e1 MD	296
ad1c05e1 MD	297	static
c0e31d2e	298	int lttng_abi_open_stream(struct file *channel_file)
ad1c05e1	299	{
c0e31d2e	300	struct ltt_channel *channel = channel_file->private_data;
ad1c05e1 MD	301	struct lib_ring_buffer *buf;
ad1c05e1 MD	302	int stream_fd, ret;
11b5a3c2	303	struct file *stream_file;
ad1c05e1	304
11b5a3c2	305	buf = channel->ops->buffer_read_open(channel->chan);
ad1c05e1 MD	306	if (!buf)
	307	return -ENOENT;
	308
1c25284c	309	stream_fd = get_unused_fd();
ad1c05e1 MD	310	if (stream_fd < 0) {
	311	ret = stream_fd;
	312	goto fd_error;
	313	}
c0e31d2e	314	stream_file = anon_inode_getfile("[lttng_stream]",
7f57c73c	315	&lib_ring_buffer_file_operations,
ad1c05e1	316	buf, O_RDWR);
c0e31d2e MD	317	if (IS_ERR(stream_file)) {
c0e31d2e MD	318	ret = PTR_ERR(stream_file);
ad1c05e1 MD	319	goto file_error;
ad1c05e1 MD	320	}
409453cb MD	321	/*
	322	* OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
	323	* FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
	324	* file descriptor, so we set FMODE_PREAD here.
	325	*/
d7b6f197	326	stream_file->f_mode \|= FMODE_PREAD;
c0e31d2e	327	fd_install(stream_fd, stream_file);
dda6a249 MD	328	/*
	329	* The stream holds a reference to the channel within the generic ring
	330	* buffer library, so no need to hold a refcount on the channel and
	331	* session files here.
	332	*/
ad1c05e1 MD	333	return stream_fd;
	334
	335	file_error:
	336	put_unused_fd(stream_fd);
	337	fd_error:
11b5a3c2	338	channel->ops->buffer_read_close(buf);
ad1c05e1 MD	339	return ret;
	340	}
	341
653fe716	342	static
c0e31d2e	343	int lttng_abi_create_event(struct file *channel_file,
653fe716 MD	344	struct lttng_event __user *uevent_param)
653fe716 MD	345	{
c0e31d2e	346	struct ltt_channel *channel = channel_file->private_data;
653fe716 MD	347	struct ltt_event *event;
	348	char *event_name;
	349	struct lttng_event event_param;
	350	int event_fd, ret;
11b5a3c2	351	struct file *event_file;
dda6a249	352	void *probe;
653fe716 MD	353
	354	if (copy_from_user(&event_param, uevent_param, sizeof(event_param)))
	355	return -EFAULT;
	356	event_name = kmalloc(PATH_MAX, GFP_KERNEL);
	357	if (!event_name)
	358	return -ENOMEM;
981616e8	359	if (strncpy_from_user(event_name, uevent_param->name, PATH_MAX) < 0) {
653fe716 MD	360	ret = -EFAULT;
	361	goto name_error;
	362	}
	363	event_name[PATH_MAX - 1] = '\0';
dda6a249 MD	364
	365	probe = ltt_probe_get(event_name);
	366	if (!probe) {
	367	ret = -ENOENT;
	368	goto probe_error;
	369	}
1c25284c	370	event_fd = get_unused_fd();
653fe716 MD	371	if (event_fd < 0) {
	372	ret = event_fd;
	373	goto fd_error;
	374	}
c0e31d2e	375	event_file = anon_inode_getfile("[lttng_event]",
3b923e5b	376	&lttng_event_fops,
03037b98	377	NULL, O_RDWR);
c0e31d2e MD	378	if (IS_ERR(event_file)) {
c0e31d2e MD	379	ret = PTR_ERR(event_file);
653fe716 MD	380	goto file_error;
653fe716 MD	381	}
03037b98 MD	382	/*
	383	* We tolerate no failure path after event creation. It will stay
	384	* invariant for the rest of the session.
	385	*/
11b5a3c2	386	event = ltt_event_create(channel, event_name, event_param.itype,
dda6a249	387	probe, NULL);
03037b98 MD	388	if (!event) {
	389	goto event_error;
	390	ret = -EEXIST;
	391	}
c0e31d2e MD	392	event_file->private_data = event;
c0e31d2e MD	393	fd_install(event_fd, event_file);
653fe716	394	/* The event holds a reference on the channel */
b0caa15a	395	atomic_long_inc(&channel_file->f_count);
03037b98	396	kfree(event_name);
653fe716 MD	397	return event_fd;
653fe716 MD	398
03037b98	399	event_error:
c0e31d2e	400	fput(event_file);
653fe716 MD	401	file_error:
	402	put_unused_fd(event_fd);
	403	fd_error:
dda6a249 MD	404	ltt_probe_put(probe);
dda6a249 MD	405	probe_error:
653fe716 MD	406	name_error:
	407	kfree(event_name);
	408	return ret;
	409	}
ad1c05e1 MD	410
	411	/**
	412	* lttng_channel_ioctl - lttng syscall through ioctl
	413	*
c0e31d2e	414	* @file: the file
ad1c05e1 MD	415	* @cmd: the command
	416	* @arg: command arg
	417	*
	418	* This ioctl implements lttng commands:
	419	* LTTNG_STREAM
	420	* Returns an event stream file descriptor or failure.
	421	* (typically, one event stream records events from one CPU)
baf20995	422	* LTTNG_EVENT
ad1c05e1	423	* Returns an event file descriptor or failure.
baf20995	424	*
baf20995 MD	425	* Channel and event file descriptors also hold a reference on the session.
baf20995 MD	426	*/
ad1c05e1	427	static
c0e31d2e	428	long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
baf20995	429	{
baf20995	430	switch (cmd) {
ad1c05e1	431	case LTTNG_STREAM:
c0e31d2e	432	return lttng_abi_open_stream(file);
baf20995	433	case LTTNG_EVENT:
c0e31d2e	434	return lttng_abi_create_event(file, (struct lttng_event __user *)arg);
baf20995 MD	435	default:
	436	return -ENOIOCTLCMD;
	437	}
	438	}
	439
5dbbdb43 MD	440	/**
	441	* lttng_metadata_ioctl - lttng syscall through ioctl
	442	*
	443	* @file: the file
	444	* @cmd: the command
	445	* @arg: command arg
	446	*
	447	* This ioctl implements lttng commands:
	448	* LTTNG_STREAM
	449	* Returns an event stream file descriptor or failure.
	450	*
	451	* Channel and event file descriptors also hold a reference on the session.
	452	*/
	453	static
	454	long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	455	{
	456	switch (cmd) {
	457	case LTTNG_STREAM:
	458	return lttng_abi_open_stream(file);
	459	default:
	460	return -ENOIOCTLCMD;
	461	}
	462	}
	463
3b923e5b MD	464	/* TODO: poll */
3b923e5b MD	465	#if 0
653fe716 MD	466	/**
	467	* lttng_channel_poll - lttng stream addition/removal monitoring
	468	*
c0e31d2e	469	* @file: the file
653fe716 MD	470	* @wait: poll table
653fe716 MD	471	*/
c0e31d2e	472	unsigned int lttng_channel_poll(struct file file, poll_table wait)
653fe716	473	{
c0e31d2e	474	struct ltt_channel *channel = file->private_data;
653fe716 MD	475	unsigned int mask = 0;
653fe716 MD	476
c0e31d2e	477	if (file->f_mode & FMODE_READ) {
653fe716	478	poll_wait_set_exclusive(wait);
c0e31d2e	479	poll_wait(file, &channel->notify_wait, wait);
653fe716 MD	480
	481	/* TODO: identify when the channel is being finalized. */
	482	if (finalized)
	483	return POLLHUP;
	484	else
	485	return POLLIN \| POLLRDNORM;
	486	}
	487	return mask;
	488
	489	}
3b923e5b	490	#endif //0
653fe716	491
0a84a57f MD	492	static
	493	int lttng_channel_release(struct inode inode, struct file file)
	494	{
	495	struct ltt_channel *channel = file->private_data;
c269fff4 MD	496
	497	if (channel)
	498	fput(channel->session->file);
0a84a57f MD	499	return 0;
	500	}
	501
ad1c05e1	502	static const struct file_operations lttng_channel_fops = {
03037b98	503	.release = lttng_channel_release,
3b923e5b MD	504	/* TODO */
3b923e5b MD	505	#if 0
653fe716	506	.poll = lttng_channel_poll,
3b923e5b	507	#endif //0
ad1c05e1	508	.unlocked_ioctl = lttng_channel_ioctl,
baf20995	509	#ifdef CONFIG_COMPAT
03037b98	510	.compat_ioctl = lttng_channel_ioctl,
baf20995	511	#endif
11b5a3c2	512	};
baf20995	513
5dbbdb43 MD	514	static const struct file_operations lttng_metadata_fops = {
	515	.release = lttng_channel_release,
	516	.unlocked_ioctl = lttng_metadata_ioctl,
	517	#ifdef CONFIG_COMPAT
	518	.compat_ioctl = lttng_metadata_ioctl,
	519	#endif
	520	};
	521
0a84a57f MD	522	static
	523	int lttng_event_release(struct inode inode, struct file file)
	524	{
	525	struct ltt_event *event = file->private_data;
c269fff4 MD	526
	527	if (event)
	528	fput(event->chan->file);
0a84a57f MD	529	return 0;
	530	}
	531
3b923e5b	532	/* TODO: filter control ioctl */
0a84a57f MD	533	static const struct file_operations lttng_event_fops = {
0a84a57f MD	534	.release = lttng_event_release,
11b5a3c2	535	};
0a84a57f	536
1c25284c	537	int __init ltt_debugfs_abi_init(void)
baf20995 MD	538	{
	539	int ret = 0;
	540
a509e133	541	vmalloc_sync_all();
11b5a3c2	542	lttng_dentry = debugfs_create_file("lttng", S_IWUSR, NULL, NULL,
f3d01b96	543	&lttng_fops);
11b5a3c2	544	if (IS_ERR(lttng_dentry) \|\| !lttng_dentry) {
baf20995 MD	545	printk(KERN_ERR "Error creating LTTng control file\n");
	546	ret = -ENOMEM;
	547	goto error;
	548	}
	549	error:
	550	return ret;
	551	}
	552
1c25284c	553	void __exit ltt_debugfs_abi_exit(void)
baf20995	554	{
11b5a3c2	555	debugfs_remove(lttng_dentry);
baf20995	556	}