summaryrefslogtreecommitdiffstats
path: root/include/linux/seq_buf.h
blob: 9aafe0e24c68515574238660d9494930dbf880c0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
#ifndef _LINUX_SEQ_BUF_H
#define _LINUX_SEQ_BUF_H

#include <linux/fs.h>

/*
 * Trace sequences are used to allow a function to call several other functions
 * to create a string of data to use.
 */

/**
 * seq_buf - seq buffer structure
 * @buffer:	pointer to the buffer
 * @size:	size of the buffer
 * @len:	the amount of data inside the buffer
 * @readpos:	The next position to read in the buffer.
 */
struct seq_buf {
	char			*buffer;
	size_t			size;
	size_t			len;
	loff_t			readpos;
};

static inline void seq_buf_clear(struct seq_buf *s)
{
	s->len = 0;
	s->readpos = 0;
}

static inline void
seq_buf_init(struct seq_buf *s, unsigned char *buf, unsigned int size)
{
	s->buffer = buf;
	s->size = size;
	seq_buf_clear(s);
}

/*
 * seq_buf have a buffer that might overflow. When this happens
 * the len and size are set to be equal.
 */
static inline bool
seq_buf_has_overflowed(struct seq_buf *s)
{
	return s->len > s->size;
}

static inline void
seq_buf_set_overflow(struct seq_buf *s)
{
	s->len = s->size + 1;
}

/*
 * How much buffer is left on the seq_buf?
 */
static inline unsigned int
seq_buf_buffer_left(struct seq_buf *s)
{
	if (seq_buf_has_overflowed(s))
		return 0;

	return s->size - s->len;
}

/* How much buffer was written? */
static inline unsigned int seq_buf_used(struct seq_buf *s)
{
	return min(s->len, s->size);
}

/**
 * seq_buf_get_buf - get buffer to write arbitrary data to
 * @s: the seq_buf handle
 * @bufp: the beginning of the buffer is stored here
 *
 * Return the number of bytes available in the buffer, or zero if
 * there's no space.
 */
static inline size_t seq_buf_get_buf(struct seq_buf *s, char **bufp)
{
	WARN_ON(s->len > s->size + 1);

	if (s->len < s->size) {
		*bufp = s->buffer + s->len;
		return s->size - s->len;
	}

	*bufp = NULL;
	return 0;
}

/**
 * seq_buf_commit - commit data to the buffer
 * @s: the seq_buf handle
 * @num: the number of bytes to commit
 *
 * Commit @num bytes of data written to a buffer previously acquired
 * by seq_buf_get.  To signal an error condition, or that the data
 * didn't fit in the available space, pass a negative @num value.
 */
static inline void seq_buf_commit(struct seq_buf *s, int num)
{
	if (num < 0) {
		seq_buf_set_overflow(s);
	} else {
		/* num must be negative on overflow */
		BUG_ON(s->len + num > s->size);
		s->len += num;
	}
}

extern __printf(2, 3)
int seq_buf_printf(struct seq_buf *s, const char *fmt, ...);
extern __printf(2, 0)
int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args);
extern int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s);
extern int seq_buf_to_user(struct seq_buf *s, char __user *ubuf,
			   int cnt);
extern int seq_buf_puts(struct seq_buf *s, const char *str);
extern int seq_buf_putc(struct seq_buf *s, unsigned char c);
extern int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len);
extern int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
			      unsigned int len);
extern int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc);

extern int seq_buf_bitmask(struct seq_buf *s, const unsigned long *maskp,
			   int nmaskbits);

#ifdef CONFIG_BINARY_PRINTF
extern int
seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary);
#endif

#endif /* _LINUX_SEQ_BUF_H */