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 */
19 struct seq_buf {
20 char *buffer;
21 size_t size;
22 size_t len;
23 loff_t readpos;
24 };
25
seq_buf_clear(struct seq_buf * s)26 static inline void seq_buf_clear(struct seq_buf *s)
27 {
28 s->len = 0;
29 s->readpos = 0;
30 }
31
32 static inline void
seq_buf_init(struct seq_buf * s,unsigned char * buf,unsigned int size)33 seq_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 */
44 static inline bool
seq_buf_has_overflowed(struct seq_buf * s)45 seq_buf_has_overflowed(struct seq_buf *s)
46 {
47 return s->len > s->size;
48 }
49
50 static inline void
seq_buf_set_overflow(struct seq_buf * s)51 seq_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 */
59 static inline unsigned int
seq_buf_buffer_left(struct seq_buf * s)60 seq_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? */
seq_buf_used(struct seq_buf * s)69 static 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 */
seq_buf_get_buf(struct seq_buf * s,char ** bufp)82 static 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 */
seq_buf_commit(struct seq_buf * s,int num)104 static 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
115 extern __printf(2, 3)
116 int seq_buf_printf(struct seq_buf *s, const char *fmt, ...);
117 extern __printf(2, 0)
118 int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args);
119 extern int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s);
120 extern int seq_buf_to_user(struct seq_buf *s, char __user *ubuf,
121 int cnt);
122 extern int seq_buf_puts(struct seq_buf *s, const char *str);
123 extern int seq_buf_putc(struct seq_buf *s, unsigned char c);
124 extern int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len);
125 extern int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
126 unsigned int len);
127 extern int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc);
128
129 #ifdef CONFIG_BINARY_PRINTF
130 extern int
131 seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary);
132 #endif
133
134 #endif /* _LINUX_SEQ_BUF_H */
135
