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 | */ |
18 | struct 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 | |
31 | static 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 | |
38 | static inline void |
39 | seq_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 | */ |
50 | static inline bool |
51 | seq_buf_has_overflowed(struct seq_buf *s) |
52 | { |
53 | return s->len > s->size; |
54 | } |
55 | |
56 | static inline void |
57 | seq_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 | */ |
65 | static inline unsigned int |
66 | seq_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? */ |
75 | static 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 | */ |
96 | static 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 | */ |
117 | static 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 | */ |
139 | static 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 | |
150 | extern __printf(2, 3) |
151 | int seq_buf_printf(struct seq_buf *s, const char *fmt, ...); |
152 | extern __printf(2, 0) |
153 | int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args); |
154 | extern int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s); |
155 | extern int seq_buf_to_user(struct seq_buf *s, char __user *ubuf, |
156 | size_t start, int cnt); |
157 | extern int seq_buf_puts(struct seq_buf *s, const char *str); |
158 | extern int seq_buf_putc(struct seq_buf *s, unsigned char c); |
159 | extern int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len); |
160 | extern int seq_buf_putmem_hex(struct seq_buf *s, const void *mem, |
161 | unsigned int len); |
162 | extern int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc); |
163 | extern 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 |
168 | extern int |
169 | seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary); |
170 | #endif |
171 | |
172 | void seq_buf_do_printk(struct seq_buf *s, const char *lvl); |
173 | |
174 | #endif /* _LINUX_SEQ_BUF_H */ |
175 | |