1#ifndef _LINUX_SEQ_FILE_H
2#define _LINUX_SEQ_FILE_H
3
4#include <linux/types.h>
5#include <linux/string.h>
6#include <linux/bug.h>
7#include <linux/mutex.h>
8#include <linux/cpumask.h>
9#include <linux/nodemask.h>
10
11struct seq_operations;
12struct file;
13struct path;
14struct inode;
15struct dentry;
16struct user_namespace;
17
18struct seq_file {
19	char *buf;
20	size_t size;
21	size_t from;
22	size_t count;
23	size_t pad_until;
24	loff_t index;
25	loff_t read_pos;
26	u64 version;
27	struct mutex lock;
28	const struct seq_operations *op;
29	int poll_event;
30#ifdef CONFIG_USER_NS
31	struct user_namespace *user_ns;
32#endif
33	void *private;
34};
35
36struct seq_operations {
37	void * (*start) (struct seq_file *m, loff_t *pos);
38	void (*stop) (struct seq_file *m, void *v);
39	void * (*next) (struct seq_file *m, void *v, loff_t *pos);
40	int (*show) (struct seq_file *m, void *v);
41};
42
43#define SEQ_SKIP 1
44
45/**
46 * seq_has_overflowed - check if the buffer has overflowed
47 * @m: the seq_file handle
48 *
49 * seq_files have a buffer which may overflow. When this happens a larger
50 * buffer is reallocated and all the data will be printed again.
51 * The overflow state is true when m->count == m->size.
52 *
53 * Returns true if the buffer received more than it can hold.
54 */
55static inline bool seq_has_overflowed(struct seq_file *m)
56{
57	return m->count == m->size;
58}
59
60/**
61 * seq_get_buf - get buffer to write arbitrary data to
62 * @m: the seq_file handle
63 * @bufp: the beginning of the buffer is stored here
64 *
65 * Return the number of bytes available in the buffer, or zero if
66 * there's no space.
67 */
68static inline size_t seq_get_buf(struct seq_file *m, char **bufp)
69{
70	BUG_ON(m->count > m->size);
71	if (m->count < m->size)
72		*bufp = m->buf + m->count;
73	else
74		*bufp = NULL;
75
76	return m->size - m->count;
77}
78
79/**
80 * seq_commit - commit data to the buffer
81 * @m: the seq_file handle
82 * @num: the number of bytes to commit
83 *
84 * Commit @num bytes of data written to a buffer previously acquired
85 * by seq_buf_get.  To signal an error condition, or that the data
86 * didn't fit in the available space, pass a negative @num value.
87 */
88static inline void seq_commit(struct seq_file *m, int num)
89{
90	if (num < 0) {
91		m->count = m->size;
92	} else {
93		BUG_ON(m->count + num > m->size);
94		m->count += num;
95	}
96}
97
98/**
99 * seq_setwidth - set padding width
100 * @m: the seq_file handle
101 * @size: the max number of bytes to pad.
102 *
103 * Call seq_setwidth() for setting max width, then call seq_printf() etc. and
104 * finally call seq_pad() to pad the remaining bytes.
105 */
106static inline void seq_setwidth(struct seq_file *m, size_t size)
107{
108	m->pad_until = m->count + size;
109}
110void seq_pad(struct seq_file *m, char c);
111
112char *mangle_path(char *s, const char *p, const char *esc);
113int seq_open(struct file *, const struct seq_operations *);
114ssize_t seq_read(struct file *, char __user *, size_t, loff_t *);
115loff_t seq_lseek(struct file *, loff_t, int);
116int seq_release(struct inode *, struct file *);
117int seq_escape(struct seq_file *, const char *, const char *);
118int seq_putc(struct seq_file *m, char c);
119int seq_puts(struct seq_file *m, const char *s);
120int seq_write(struct seq_file *seq, const void *data, size_t len);
121
122__printf(2, 3) int seq_printf(struct seq_file *, const char *, ...);
123__printf(2, 0) int seq_vprintf(struct seq_file *, const char *, va_list args);
124
125int seq_path(struct seq_file *, const struct path *, const char *);
126int seq_dentry(struct seq_file *, struct dentry *, const char *);
127int seq_path_root(struct seq_file *m, const struct path *path,
128		  const struct path *root, const char *esc);
129
130int single_open(struct file *, int (*)(struct seq_file *, void *), void *);
131int single_open_size(struct file *, int (*)(struct seq_file *, void *), void *, size_t);
132int single_release(struct inode *, struct file *);
133void *__seq_open_private(struct file *, const struct seq_operations *, int);
134int seq_open_private(struct file *, const struct seq_operations *, int);
135int seq_release_private(struct inode *, struct file *);
136int seq_put_decimal_ull(struct seq_file *m, char delimiter,
137			unsigned long long num);
138int seq_put_decimal_ll(struct seq_file *m, char delimiter,
139			long long num);
140
141static inline struct user_namespace *seq_user_ns(struct seq_file *seq)
142{
143#ifdef CONFIG_USER_NS
144	return seq->user_ns;
145#else
146	extern struct user_namespace init_user_ns;
147	return &init_user_ns;
148#endif
149}
150
151/**
152 * seq_show_options - display mount options with appropriate escapes.
153 * @m: the seq_file handle
154 * @name: the mount option name
155 * @value: the mount option name's value, can be NULL
156 */
157static inline void seq_show_option(struct seq_file *m, const char *name,
158				   const char *value)
159{
160	seq_putc(m, ',');
161	seq_escape(m, name, ",= \t\n\\");
162	if (value) {
163		seq_putc(m, '=');
164		seq_escape(m, value, ", \t\n\\");
165	}
166}
167
168/**
169 * seq_show_option_n - display mount options with appropriate escapes
170 *		       where @value must be a specific length.
171 * @m: the seq_file handle
172 * @name: the mount option name
173 * @value: the mount option name's value, cannot be NULL
174 * @length: the length of @value to display
175 *
176 * This is a macro since this uses "length" to define the size of the
177 * stack buffer.
178 */
179#define seq_show_option_n(m, name, value, length) {	\
180	char val_buf[length + 1];			\
181	strncpy(val_buf, value, length);		\
182	val_buf[length] = '\0';				\
183	seq_show_option(m, name, val_buf);		\
184}
185
186#define SEQ_START_TOKEN ((void *)1)
187/*
188 * Helpers for iteration over list_head-s in seq_files
189 */
190
191extern struct list_head *seq_list_start(struct list_head *head,
192		loff_t pos);
193extern struct list_head *seq_list_start_head(struct list_head *head,
194		loff_t pos);
195extern struct list_head *seq_list_next(void *v, struct list_head *head,
196		loff_t *ppos);
197
198/*
199 * Helpers for iteration over hlist_head-s in seq_files
200 */
201
202extern struct hlist_node *seq_hlist_start(struct hlist_head *head,
203					  loff_t pos);
204extern struct hlist_node *seq_hlist_start_head(struct hlist_head *head,
205					       loff_t pos);
206extern struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head,
207					 loff_t *ppos);
208
209extern struct hlist_node *seq_hlist_start_rcu(struct hlist_head *head,
210					      loff_t pos);
211extern struct hlist_node *seq_hlist_start_head_rcu(struct hlist_head *head,
212						   loff_t pos);
213extern struct hlist_node *seq_hlist_next_rcu(void *v,
214						   struct hlist_head *head,
215						   loff_t *ppos);
216
217/* Helpers for iterating over per-cpu hlist_head-s in seq_files */
218extern struct hlist_node *seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos);
219
220extern struct hlist_node *seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head, int *cpu, loff_t *pos);
221
222#endif
223