Linux kernel mirror (for testing)
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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 */
18struct seq_buf {
19 char *buffer;
20 size_t size;
21 size_t len;
22};
23
24#define DECLARE_SEQ_BUF(NAME, SIZE) \
25 char __ ## NAME ## _buffer[SIZE] = ""; \
26 struct seq_buf NAME = { \
27 .buffer = &__ ## NAME ## _buffer, \
28 .size = SIZE, \
29 }
30
31static inline void seq_buf_clear(struct seq_buf *s)
32{
33 s->len = 0;
34 if (s->size)
35 s->buffer[0] = '\0';
36}
37
38static inline void
39seq_buf_init(struct seq_buf *s, char *buf, unsigned int size)
40{
41 s->buffer = buf;
42 s->size = size;
43 seq_buf_clear(s);
44}
45
46/*
47 * seq_buf have a buffer that might overflow. When this happens
48 * len is set to be greater than size.
49 */
50static inline bool
51seq_buf_has_overflowed(struct seq_buf *s)
52{
53 return s->len > s->size;
54}
55
56static inline void
57seq_buf_set_overflow(struct seq_buf *s)
58{
59 s->len = s->size + 1;
60}
61
62/*
63 * How much buffer is left on the seq_buf?
64 */
65static inline unsigned int
66seq_buf_buffer_left(struct seq_buf *s)
67{
68 if (seq_buf_has_overflowed(s))
69 return 0;
70
71 return s->size - s->len;
72}
73
74/* How much buffer was written? */
75static inline unsigned int seq_buf_used(struct seq_buf *s)
76{
77 return min(s->len, s->size);
78}
79
80/**
81 * seq_buf_str - get %NUL-terminated C string from seq_buf
82 * @s: the seq_buf handle
83 *
84 * This makes sure that the buffer in @s is nul terminated and
85 * safe to read as a string.
86 *
87 * Note, if this is called when the buffer has overflowed, then
88 * the last byte of the buffer is zeroed, and the len will still
89 * point passed it.
90 *
91 * After this function is called, s->buffer is safe to use
92 * in string operations.
93 *
94 * Returns @s->buf after making sure it is terminated.
95 */
96static inline const char *seq_buf_str(struct seq_buf *s)
97{
98 if (WARN_ON(s->size == 0))
99 return "";
100
101 if (seq_buf_buffer_left(s))
102 s->buffer[s->len] = 0;
103 else
104 s->buffer[s->size - 1] = 0;
105
106 return s->buffer;
107}
108
109/**
110 * seq_buf_get_buf - get buffer to write arbitrary data to
111 * @s: the seq_buf handle
112 * @bufp: the beginning of the buffer is stored here
113 *
114 * Return the number of bytes available in the buffer, or zero if
115 * there's no space.
116 */
117static inline size_t seq_buf_get_buf(struct seq_buf *s, char **bufp)
118{
119 WARN_ON(s->len > s->size + 1);
120
121 if (s->len < s->size) {
122 *bufp = s->buffer + s->len;
123 return s->size - s->len;
124 }
125
126 *bufp = NULL;
127 return 0;
128}
129
130/**
131 * seq_buf_commit - commit data to the buffer
132 * @s: the seq_buf handle
133 * @num: the number of bytes to commit
134 *
135 * Commit @num bytes of data written to a buffer previously acquired
136 * by seq_buf_get. To signal an error condition, or that the data
137 * didn't fit in the available space, pass a negative @num value.
138 */
139static inline void seq_buf_commit(struct seq_buf *s, int num)
140{
141 if (num < 0) {
142 seq_buf_set_overflow(s);
143 } else {
144 /* num must be negative on overflow */
145 BUG_ON(s->len + num > s->size);
146 s->len += num;
147 }
148}
149
150extern __printf(2, 3)
151int seq_buf_printf(struct seq_buf *s, const char *fmt, ...);
152extern __printf(2, 0)
153int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args);
154extern int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s);
155extern int seq_buf_to_user(struct seq_buf *s, char __user *ubuf,
156 size_t start, int cnt);
157extern int seq_buf_puts(struct seq_buf *s, const char *str);
158extern int seq_buf_putc(struct seq_buf *s, unsigned char c);
159extern int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len);
160extern int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
161 unsigned int len);
162extern int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc);
163extern int seq_buf_hex_dump(struct seq_buf *s, const char *prefix_str,
164 int prefix_type, int rowsize, int groupsize,
165 const void *buf, size_t len, bool ascii);
166
167#ifdef CONFIG_BINARY_PRINTF
168extern int
169seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary);
170#endif
171
172void seq_buf_do_printk(struct seq_buf *s, const char *lvl);
173
174#endif /* _LINUX_SEQ_BUF_H */