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
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
|
// SPDX-License-Identifier: GPL-2.0
/*
* seq_buf.c
*
* Copyright (C) 2014 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
*
* The seq_buf is a handy tool that allows you to pass a descriptor around
* to a buffer that other functions can write to. It is similar to the
* seq_file functionality but has some differences.
*
* To use it, the seq_buf must be initialized with seq_buf_init().
* This will set up the counters within the descriptor. You can call
* seq_buf_init() more than once to reset the seq_buf to start
* from scratch.
*/
#include <linux/seq_buf.h>
#include <stdio.h>
/**
* seq_buf_can_fit - can the new data fit in the current buffer?
* @s: the seq_buf descriptor
* @len: The length to see if it can fit in the current buffer
*
* Returns true if there's enough unused space in the seq_buf buffer
* to fit the amount of new data according to @len.
*/
static bool seq_buf_can_fit(struct seq_buf *s, size_t len)
{
return s->len + len <= s->size;
}
/**
* seq_buf_vprintf - sequence printing of information.
* @s: seq_buf descriptor
* @fmt: printf format string
* @args: va_list of arguments from a printf() type function
*
* Writes a vnprintf() format into the sequencce buffer.
*
* Returns zero on success, -1 on overflow.
*/
int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args)
{
int len;
WARN_ON(s->size == 0);
if (s->len < s->size) {
len = vsnprintf(s->buffer + s->len, s->size - s->len, fmt, args);
if (s->len + len < s->size) {
s->len += len;
return 0;
}
}
seq_buf_set_overflow(s);
return -1;
}
/**
* seq_buf_printf - sequence printing of information
* @s: seq_buf descriptor
* @fmt: printf format string
*
* Writes a printf() format into the sequence buffer.
*
* Returns zero on success, -1 on overflow.
*/
int seq_buf_printf(struct seq_buf *s, const char *fmt, ...)
{
va_list ap;
int ret;
va_start(ap, fmt);
ret = seq_buf_vprintf(s, fmt, ap);
va_end(ap);
return ret;
}
/**
* seq_buf_puts - sequence printing of simple string
* @s: seq_buf descriptor
* @str: simple string to record
*
* Copy a simple string into the sequence buffer.
*
* Returns zero on success, -1 on overflow
*/
int seq_buf_puts(struct seq_buf *s, const char *str)
{
size_t len = strlen(str);
WARN_ON(s->size == 0);
/* Add 1 to len for the trailing null byte which must be there */
len += 1;
if (seq_buf_can_fit(s, len)) {
memcpy(s->buffer + s->len, str, len);
/* Don't count the trailing null byte against the capacity */
s->len += len - 1;
return 0;
}
seq_buf_set_overflow(s);
return -1;
}
/**
* seq_buf_putc - sequence printing of simple character
* @s: seq_buf descriptor
* @c: simple character to record
*
* Copy a single character into the sequence buffer.
*
* Returns zero on success, -1 on overflow
*/
int seq_buf_putc(struct seq_buf *s, unsigned char c)
{
WARN_ON(s->size == 0);
if (seq_buf_can_fit(s, 1)) {
s->buffer[s->len++] = c;
return 0;
}
seq_buf_set_overflow(s);
return -1;
}
/**
* seq_buf_putmem - write raw data into the sequenc buffer
* @s: seq_buf descriptor
* @mem: The raw memory to copy into the buffer
* @len: The length of the raw memory to copy (in bytes)
*
* There may be cases where raw memory needs to be written into the
* buffer and a strcpy() would not work. Using this function allows
* for such cases.
*
* Returns zero on success, -1 on overflow
*/
int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len)
{
WARN_ON(s->size == 0);
if (seq_buf_can_fit(s, len)) {
memcpy(s->buffer + s->len, mem, len);
s->len += len;
return 0;
}
seq_buf_set_overflow(s);
return -1;
}
|
