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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
3a161d99 SRRH |
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 { | |
9a777793 SRRH |
20 | char *buffer; |
21 | size_t size; | |
22 | size_t len; | |
23 | loff_t readpos; | |
3a161d99 SRRH |
24 | }; |
25 | ||
0736c033 SRRH |
26 | static inline void seq_buf_clear(struct seq_buf *s) |
27 | { | |
28 | s->len = 0; | |
29 | s->readpos = 0; | |
30 | } | |
31 | ||
3a161d99 | 32 | static inline void |
d9a9280a | 33 | seq_buf_init(struct seq_buf *s, char *buf, unsigned int size) |
3a161d99 SRRH |
34 | { |
35 | s->buffer = buf; | |
36 | s->size = size; | |
0736c033 | 37 | seq_buf_clear(s); |
3a161d99 SRRH |
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 | |
45 | seq_buf_has_overflowed(struct seq_buf *s) | |
46 | { | |
8cd709ae | 47 | return s->len > s->size; |
3a161d99 SRRH |
48 | } |
49 | ||
50 | static inline void | |
51 | seq_buf_set_overflow(struct seq_buf *s) | |
52 | { | |
8cd709ae | 53 | s->len = s->size + 1; |
3a161d99 SRRH |
54 | } |
55 | ||
56 | /* | |
57 | * How much buffer is left on the seq_buf? | |
58 | */ | |
59 | static inline unsigned int | |
60 | seq_buf_buffer_left(struct seq_buf *s) | |
61 | { | |
62 | if (seq_buf_has_overflowed(s)) | |
63 | return 0; | |
64 | ||
8cd709ae | 65 | return s->size - s->len; |
3a161d99 SRRH |
66 | } |
67 | ||
eeab9815 SRRH |
68 | /* How much buffer was written? */ |
69 | static inline unsigned int seq_buf_used(struct seq_buf *s) | |
70 | { | |
71 | return min(s->len, s->size); | |
72 | } | |
73 | ||
f2616c77 SRV |
74 | /** |
75 | * seq_buf_terminate - Make sure buffer is nul terminated | |
76 | * @s: the seq_buf descriptor to terminate. | |
77 | * | |
78 | * This makes sure that the buffer in @s is nul terminated and | |
79 | * safe to read as a string. | |
80 | * | |
81 | * Note, if this is called when the buffer has overflowed, then | |
82 | * the last byte of the buffer is zeroed, and the len will still | |
83 | * point passed it. | |
84 | * | |
85 | * After this function is called, s->buffer is safe to use | |
86 | * in string operations. | |
87 | */ | |
88 | static inline void seq_buf_terminate(struct seq_buf *s) | |
89 | { | |
90 | if (WARN_ON(s->size == 0)) | |
91 | return; | |
92 | ||
93 | if (seq_buf_buffer_left(s)) | |
94 | s->buffer[s->len] = 0; | |
95 | else | |
96 | s->buffer[s->size - 1] = 0; | |
97 | } | |
98 | ||
01cb06a4 SRRH |
99 | /** |
100 | * seq_buf_get_buf - get buffer to write arbitrary data to | |
101 | * @s: the seq_buf handle | |
102 | * @bufp: the beginning of the buffer is stored here | |
103 | * | |
104 | * Return the number of bytes available in the buffer, or zero if | |
105 | * there's no space. | |
106 | */ | |
107 | static inline size_t seq_buf_get_buf(struct seq_buf *s, char **bufp) | |
108 | { | |
109 | WARN_ON(s->len > s->size + 1); | |
110 | ||
111 | if (s->len < s->size) { | |
112 | *bufp = s->buffer + s->len; | |
113 | return s->size - s->len; | |
114 | } | |
115 | ||
116 | *bufp = NULL; | |
117 | return 0; | |
118 | } | |
119 | ||
120 | /** | |
121 | * seq_buf_commit - commit data to the buffer | |
122 | * @s: the seq_buf handle | |
123 | * @num: the number of bytes to commit | |
124 | * | |
125 | * Commit @num bytes of data written to a buffer previously acquired | |
126 | * by seq_buf_get. To signal an error condition, or that the data | |
127 | * didn't fit in the available space, pass a negative @num value. | |
128 | */ | |
129 | static inline void seq_buf_commit(struct seq_buf *s, int num) | |
130 | { | |
131 | if (num < 0) { | |
132 | seq_buf_set_overflow(s); | |
133 | } else { | |
134 | /* num must be negative on overflow */ | |
135 | BUG_ON(s->len + num > s->size); | |
136 | s->len += num; | |
137 | } | |
138 | } | |
139 | ||
3a161d99 SRRH |
140 | extern __printf(2, 3) |
141 | int seq_buf_printf(struct seq_buf *s, const char *fmt, ...); | |
142 | extern __printf(2, 0) | |
143 | int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args); | |
3a161d99 SRRH |
144 | extern int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s); |
145 | extern int seq_buf_to_user(struct seq_buf *s, char __user *ubuf, | |
146 | int cnt); | |
147 | extern int seq_buf_puts(struct seq_buf *s, const char *str); | |
148 | extern int seq_buf_putc(struct seq_buf *s, unsigned char c); | |
149 | extern int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len); | |
150 | extern int seq_buf_putmem_hex(struct seq_buf *s, const void *mem, | |
151 | unsigned int len); | |
dd23180a | 152 | extern int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc); |
353cade3 PM |
153 | extern int seq_buf_hex_dump(struct seq_buf *s, const char *prefix_str, |
154 | int prefix_type, int rowsize, int groupsize, | |
155 | const void *buf, size_t len, bool ascii); | |
3a161d99 | 156 | |
2448913e SRRH |
157 | #ifdef CONFIG_BINARY_PRINTF |
158 | extern int | |
159 | seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary); | |
160 | #endif | |
161 | ||
3a161d99 | 162 | #endif /* _LINUX_SEQ_BUF_H */ |