1/* SPDX-License-Identifier: GPL-2.0-only */
 2/*
 3 *  tracefs.h - a pseudo file system for activating tracing
 4 *
 5 * Based on debugfs by: 2004 Greg Kroah-Hartman <greg@kroah.com>
 6 *
 7 *  Copyright (C) 2014 Red Hat Inc, author: Steven Rostedt <srostedt@redhat.com>
 8 *
 9 * tracefs is the file system that is used by the tracing infrastructure.
10 */
11
12#ifndef _TRACEFS_H_
13#define _TRACEFS_H_
14
15#include <linux/fs.h>
16#include <linux/seq_file.h>
17
18#include <linux/types.h>
19
20struct file_operations;
21
22#ifdef CONFIG_TRACING
23
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
24struct dentry *tracefs_create_file(const char *name, umode_t mode,
25				   struct dentry *parent, void *data,
26				   const struct file_operations *fops);
27
28struct dentry *tracefs_create_dir(const char *name, struct dentry *parent);
29
30void tracefs_remove(struct dentry *dentry);
31
32struct dentry *tracefs_create_instance_dir(const char *name, struct dentry *parent,
33					   int (*mkdir)(const char *name),
34					   int (*rmdir)(const char *name));
35
36bool tracefs_initialized(void);
37
38#endif /* CONFIG_TRACING */
39
40#endif

  1/* SPDX-License-Identifier: GPL-2.0-only */
  2/*
  3 *  tracefs.h - a pseudo file system for activating tracing
  4 *
  5 * Based on debugfs by: 2004 Greg Kroah-Hartman <greg@kroah.com>
  6 *
  7 *  Copyright (C) 2014 Red Hat Inc, author: Steven Rostedt <srostedt@redhat.com>
  8 *
  9 * tracefs is the file system that is used by the tracing infrastructure.
 10 */
 11
 12#ifndef _TRACEFS_H_
 13#define _TRACEFS_H_
 14
 15#include <linux/fs.h>
 16#include <linux/seq_file.h>
 17
 18#include <linux/types.h>
 19
 20struct file_operations;
 21
 22#ifdef CONFIG_TRACING
 23
 24struct eventfs_file;
 25
 26/**
 27 * eventfs_callback - A callback function to create dynamic files in eventfs
 28 * @name: The name of the file that is to be created
 29 * @mode: return the file mode for the file (RW access, etc)
 30 * @data: data to pass to the created file ops
 31 * @fops: the file operations of the created file
 32 *
 33 * The evetnfs files are dynamically created. The struct eventfs_entry array
 34 * is passed to eventfs_create_dir() or eventfs_create_events_dir() that will
 35 * be used to create the files within those directories. When a lookup
 36 * or access to a file within the directory is made, the struct eventfs_entry
 37 * array is used to find a callback() with the matching name that is being
 38 * referenced (for lookups, the entire array is iterated and each callback
 39 * will be called).
 40 *
 41 * The callback will be called with @name for the name of the file to create.
 42 * The callback can return less than 1 to indicate  that no file should be
 43 * created.
 44 *
 45 * If a file is to be created, then @mode should be populated with the file
 46 * mode (permissions) for which the file is created for. This would be
 47 * used to set the created inode i_mode field.
 48 *
 49 * The @data should be set to the data passed to the other file operations
 50 * (read, write, etc). Note, @data will also point to the data passed in
 51 * to eventfs_create_dir() or eventfs_create_events_dir(), but the callback
 52 * can replace the data if it chooses to. Otherwise, the original data
 53 * will be used for the file operation functions.
 54 *
 55 * The @fops should be set to the file operations that will be used to create
 56 * the inode.
 57 *
 58 * NB. This callback is called while holding internal locks of the eventfs
 59 *     system. The callback must not call any code that might also call into
 60 *     the tracefs or eventfs system or it will risk creating a deadlock.
 61 */
 62typedef int (*eventfs_callback)(const char *name, umode_t *mode, void **data,
 63				const struct file_operations **fops);
 64
 65typedef void (*eventfs_release)(const char *name, void *data);
 66
 67/**
 68 * struct eventfs_entry - dynamically created eventfs file call back handler
 69 * @name:	Then name of the dynamic file in an eventfs directory
 70 * @callback:	The callback to get the fops of the file when it is created
 71 *
 72 * See evenfs_callback() typedef for how to set up @callback.
 73 */
 74struct eventfs_entry {
 75	const char			*name;
 76	eventfs_callback		callback;
 77	eventfs_release			release;
 78};
 79
 80struct eventfs_inode;
 81
 82struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry *parent,
 83						const struct eventfs_entry *entries,
 84						int size, void *data);
 85
 86struct eventfs_inode *eventfs_create_dir(const char *name, struct eventfs_inode *parent,
 87					 const struct eventfs_entry *entries,
 88					 int size, void *data);
 89
 90void eventfs_remove_events_dir(struct eventfs_inode *ei);
 91void eventfs_remove_dir(struct eventfs_inode *ei);
 92
 93struct dentry *tracefs_create_file(const char *name, umode_t mode,
 94				   struct dentry *parent, void *data,
 95				   const struct file_operations *fops);
 96
 97struct dentry *tracefs_create_dir(const char *name, struct dentry *parent);
 98
 99void tracefs_remove(struct dentry *dentry);
100
101struct dentry *tracefs_create_instance_dir(const char *name, struct dentry *parent,
102					   int (*mkdir)(const char *name),
103					   int (*rmdir)(const char *name));
104
105bool tracefs_initialized(void);
106
107#endif /* CONFIG_TRACING */
108
109#endif