1#ifndef _LINUX_SEQ_BUF_H
2#define _LINUX_SEQ_BUF_H
3
4#include <linux/fs.h>
5
6/*
7 * Trace sequences are used to allow a function to call several other functions
8 * to create a string of data to use.
9 */
10
11/**
12 * seq_buf - seq buffer structure
13 * @buffer:	pointer to the buffer
14 * @size:	size of the buffer
15 * @len:	the amount of data inside the buffer
16 * @readpos:	The next position to read in the buffer.
17 */
18struct seq_buf {
19	char			*buffer;
20	size_t			size;
21	size_t			len;
22	loff_t			readpos;
23};
24
25static inline void seq_buf_clear(struct seq_buf *s)
26{
27	s->len = 0;
28	s->readpos = 0;
29}
30
31static inline void
32seq_buf_init(struct seq_buf *s, unsigned char *buf, unsigned int size)
33{
34	s->buffer = buf;
35	s->size = size;
36	seq_buf_clear(s);
37}
38
39/*
40 * seq_buf have a buffer that might overflow. When this happens
41 * the len and size are set to be equal.
42 */
43static inline bool
44seq_buf_has_overflowed(struct seq_buf *s)
45{
46	return s->len > s->size;
47}
48
49static inline void
50seq_buf_set_overflow(struct seq_buf *s)
51{
52	s->len = s->size + 1;
53}
54
55/*
56 * How much buffer is left on the seq_buf?
57 */
58static inline unsigned int
59seq_buf_buffer_left(struct seq_buf *s)
60{
61	if (seq_buf_has_overflowed(s))
62		return 0;
63
64	return s->size - s->len;
65}
66
67/* How much buffer was written? */
68static inline unsigned int seq_buf_used(struct seq_buf *s)
69{
70	return min(s->len, s->size);
71}
72
73/**
74 * seq_buf_get_buf - get buffer to write arbitrary data to
75 * @s: the seq_buf handle
76 * @bufp: the beginning of the buffer is stored here
77 *
78 * Return the number of bytes available in the buffer, or zero if
79 * there's no space.
80 */
81static inline size_t seq_buf_get_buf(struct seq_buf *s, char **bufp)
82{
83	WARN_ON(s->len > s->size + 1);
84
85	if (s->len < s->size) {
86		*bufp = s->buffer + s->len;
87		return s->size - s->len;
88	}
89
90	*bufp = NULL;
91	return 0;
92}
93
94/**
95 * seq_buf_commit - commit data to the buffer
96 * @s: the seq_buf handle
97 * @num: the number of bytes to commit
98 *
99 * Commit @num bytes of data written to a buffer previously acquired
100 * by seq_buf_get.  To signal an error condition, or that the data
101 * didn't fit in the available space, pass a negative @num value.
102 */
103static inline void seq_buf_commit(struct seq_buf *s, int num)
104{
105	if (num < 0) {
106		seq_buf_set_overflow(s);
107	} else {
108		/* num must be negative on overflow */
109		BUG_ON(s->len + num > s->size);
110		s->len += num;
111	}
112}
113
114extern __printf(2, 3)
115int seq_buf_printf(struct seq_buf *s, const char *fmt, ...);
116extern __printf(2, 0)
117int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args);
118extern int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s);
119extern int seq_buf_to_user(struct seq_buf *s, char __user *ubuf,
120			   int cnt);
121extern int seq_buf_puts(struct seq_buf *s, const char *str);
122extern int seq_buf_putc(struct seq_buf *s, unsigned char c);
123extern int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len);
124extern int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
125			      unsigned int len);
126extern int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc);
127
128#ifdef CONFIG_BINARY_PRINTF
129extern int
130seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary);
131#endif
132
133#endif /* _LINUX_SEQ_BUF_H */
134