1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_SEQ_BUF_H
3#define _LINUX_SEQ_BUF_H
4
5#include <linux/fs.h>
6
7/*
8 * Trace sequences are used to allow a function to call several other functions
9 * to create a string of data to use.
10 */
11
12/**
13 * seq_buf - seq buffer structure
14 * @buffer: pointer to the buffer
15 * @size: size of the buffer
16 * @len: the amount of data inside the buffer
17 * @readpos: The next position to read in the buffer.
18 */
19struct seq_buf {
20 char *buffer;
21 size_t size;
22 size_t len;
23 loff_t readpos;
24};
25
26static inline void seq_buf_clear(struct seq_buf *s)
27{
28 s->len = 0;
29 s->readpos = 0;
30}
31
32static inline void
33seq_buf_init(struct seq_buf *s, unsigned char *buf, unsigned int size)
34{
35 s->buffer = buf;
36 s->size = size;
37 seq_buf_clear(s);
38}
39
40/*
41 * seq_buf have a buffer that might overflow. When this happens
42 * the len and size are set to be equal.
43 */
44static inline bool
45seq_buf_has_overflowed(struct seq_buf *s)
46{
47 return s->len > s->size;
48}
49
50static inline void
51seq_buf_set_overflow(struct seq_buf *s)
52{
53 s->len = s->size + 1;
54}
55
56/*
57 * How much buffer is left on the seq_buf?
58 */
59static inline unsigned int
60seq_buf_buffer_left(struct seq_buf *s)
61{
62 if (seq_buf_has_overflowed(s))
63 return 0;
64
65 return s->size - s->len;
66}
67
68/* How much buffer was written? */
69static inline unsigned int seq_buf_used(struct seq_buf *s)
70{
71 return min(s->len, s->size);
72}
73
74/**
75 * seq_buf_get_buf - get buffer to write arbitrary data to
76 * @s: the seq_buf handle
77 * @bufp: the beginning of the buffer is stored here
78 *
79 * Return the number of bytes available in the buffer, or zero if
80 * there's no space.
81 */
82static inline size_t seq_buf_get_buf(struct seq_buf *s, char **bufp)
83{
84 WARN_ON(s->len > s->size + 1);
85
86 if (s->len < s->size) {
87 *bufp = s->buffer + s->len;
88 return s->size - s->len;
89 }
90
91 *bufp = NULL;
92 return 0;
93}
94
95/**
96 * seq_buf_commit - commit data to the buffer
97 * @s: the seq_buf handle
98 * @num: the number of bytes to commit
99 *
100 * Commit @num bytes of data written to a buffer previously acquired
101 * by seq_buf_get. To signal an error condition, or that the data
102 * didn't fit in the available space, pass a negative @num value.
103 */
104static inline void seq_buf_commit(struct seq_buf *s, int num)
105{
106 if (num < 0) {
107 seq_buf_set_overflow(s);
108 } else {
109 /* num must be negative on overflow */
110 BUG_ON(s->len + num > s->size);
111 s->len += num;
112 }
113}
114
115extern __printf(2, 3)
116int seq_buf_printf(struct seq_buf *s, const char *fmt, ...);
117extern __printf(2, 0)
118int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args);
119extern int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s);
120extern int seq_buf_to_user(struct seq_buf *s, char __user *ubuf,
121 int cnt);
122extern int seq_buf_puts(struct seq_buf *s, const char *str);
123extern int seq_buf_putc(struct seq_buf *s, unsigned char c);
124extern int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len);
125extern int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
126 unsigned int len);
127extern int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc);
128
129#ifdef CONFIG_BINARY_PRINTF
130extern int
131seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary);
132#endif
133
134#endif /* _LINUX_SEQ_BUF_H */
135