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Commit 6de58e62 authored by Steven Rostedt (Red Hat)'s avatar Steven Rostedt (Red Hat) Committed by Steven Rostedt
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tracing: Add snapshot_raw to extract the raw data from snapshot 



Add a 'snapshot_raw' per_cpu file that allows tools to read the raw
binary data of the snapshot buffer.

Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 0b85ffc2

kernel/trace/trace.c

+95 −18
Original line number Diff line number Diff line
@@ -4206,6 +4206,12 @@ static int tracing_clock_open(struct inode *inode, struct file *file) 
	return single_open(file, tracing_clock_show, inode->i_private);

}



struct ftrace_buffer_info {

	struct trace_iterator	iter;

	void			*spare;

	unsigned int		read;

};



#ifdef CONFIG_TRACER_SNAPSHOT

static int tracing_snapshot_open(struct inode *inode, struct file *file)

{
@@ -4336,6 +4342,35 @@ static int tracing_snapshot_release(struct inode *inode, struct file *file) 
	return 0;

}



static int tracing_buffers_open(struct inode *inode, struct file *filp);

static ssize_t tracing_buffers_read(struct file *filp, char __user *ubuf,

				    size_t count, loff_t *ppos);

static int tracing_buffers_release(struct inode *inode, struct file *file);

static ssize_t tracing_buffers_splice_read(struct file *file, loff_t *ppos,

		   struct pipe_inode_info *pipe, size_t len, unsigned int flags);



static int snapshot_raw_open(struct inode *inode, struct file *filp)

{

	struct ftrace_buffer_info *info;

	int ret;



	ret = tracing_buffers_open(inode, filp);

	if (ret < 0)

		return ret;



	info = filp->private_data;



	if (info->iter.trace->use_max_tr) {

		tracing_buffers_release(inode, filp);

		return -EBUSY;

	}



	info->iter.snapshot = true;

	info->iter.trace_buffer = &info->iter.tr->max_buffer;



	return ret;

}



#endif /* CONFIG_TRACER_SNAPSHOT */
@@ -4402,14 +4437,17 @@ static const struct file_operations snapshot_fops = { 
	.llseek		= tracing_seek,

	.release	= tracing_snapshot_release,

};

#endif /* CONFIG_TRACER_SNAPSHOT */



struct ftrace_buffer_info {

	struct trace_iterator	iter;

	void			*spare;

	unsigned int		read;

static const struct file_operations snapshot_raw_fops = {

	.open		= snapshot_raw_open,

	.read		= tracing_buffers_read,

	.release	= tracing_buffers_release,

	.splice_read	= tracing_buffers_splice_read,

	.llseek		= no_llseek,

};



#endif /* CONFIG_TRACER_SNAPSHOT */



static int tracing_buffers_open(struct inode *inode, struct file *filp)

{

	struct trace_cpu *tc = inode->i_private;
@@ -4452,16 +4490,26 @@ tracing_buffers_read(struct file *filp, char __user *ubuf, 
	struct ftrace_buffer_info *info = filp->private_data;

	struct trace_iterator *iter = &info->iter;

	ssize_t ret;

	size_t size;

	ssize_t size;



	if (!count)

		return 0;



	mutex_lock(&trace_types_lock);



#ifdef CONFIG_TRACER_MAX_TRACE

	if (iter->snapshot && iter->tr->current_trace->use_max_tr) {

		size = -EBUSY;

		goto out_unlock;

	}

#endif



	if (!info->spare)

		info->spare = ring_buffer_alloc_read_page(iter->trace_buffer->buffer,

							  iter->cpu_file);

	size = -ENOMEM;

	if (!info->spare)

		return -ENOMEM;

		goto out_unlock;



	/* Do we have previous read data to read? */

	if (info->read < PAGE_SIZE)
@@ -4477,31 +4525,42 @@ tracing_buffers_read(struct file *filp, char __user *ubuf, 


	if (ret < 0) {

		if (trace_empty(iter)) {

			if ((filp->f_flags & O_NONBLOCK))

				return -EAGAIN;

			if ((filp->f_flags & O_NONBLOCK)) {

				size = -EAGAIN;

				goto out_unlock;

			}

			mutex_unlock(&trace_types_lock);

			iter->trace->wait_pipe(iter);

			if (signal_pending(current))

				return -EINTR;

			mutex_lock(&trace_types_lock);

			if (signal_pending(current)) {

				size = -EINTR;

				goto out_unlock;

			}

			goto again;

		}

		return 0;

		size = 0;

		goto out_unlock;

	}



	info->read = 0;



 read:

	size = PAGE_SIZE - info->read;

	if (size > count)

		size = count;



	ret = copy_to_user(ubuf, info->spare + info->read, size);

	if (ret == size)

		return -EFAULT;

	if (ret == size) {

		size = -EFAULT;

		goto out_unlock;

	}

	size -= ret;



	*ppos += size;

	info->read += size;



 out_unlock:

	mutex_unlock(&trace_types_lock);



	return size;

}
@@ -4591,10 +4650,21 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos, 
	};

	struct buffer_ref *ref;

	int entries, size, i;

	size_t ret;

	ssize_t ret;



	if (splice_grow_spd(pipe, &spd))

		return -ENOMEM;

	mutex_lock(&trace_types_lock);



#ifdef CONFIG_TRACER_MAX_TRACE

	if (iter->snapshot && iter->tr->current_trace->use_max_tr) {

		ret = -EBUSY;

		goto out;

	}

#endif



	if (splice_grow_spd(pipe, &spd)) {

		ret = -ENOMEM;

		goto out;

	}



	if (*ppos & (PAGE_SIZE - 1)) {

		ret = -EINVAL;
@@ -4666,7 +4736,9 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos, 
			ret = -EAGAIN;

			goto out;

		}

		mutex_unlock(&trace_types_lock);

		iter->trace->wait_pipe(iter);

		mutex_lock(&trace_types_lock);

		if (signal_pending(current)) {

			ret = -EINTR;

			goto out;
@@ -4677,6 +4749,8 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos, 
	ret = splice_to_pipe(pipe, &spd);

	splice_shrink_spd(&spd);

out:

	mutex_unlock(&trace_types_lock);



	return ret;

}
@@ -4880,6 +4954,9 @@ tracing_init_debugfs_percpu(struct trace_array *tr, long cpu) 
#ifdef CONFIG_TRACER_SNAPSHOT

	trace_create_file("snapshot", 0644, d_cpu,

			  (void *)&data->trace_cpu, &snapshot_fops);



	trace_create_file("snapshot_raw", 0444, d_cpu,

			(void *)&data->trace_cpu, &snapshot_raw_fops);

#endif

}