1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | #ifndef _LINUX_SEQ_BUF_H |
3 | #define _LINUX_SEQ_BUF_H |
4 | |
5 | #include <linux/bug.h> |
6 | #include <linux/minmax.h> |
7 | #include <linux/seq_file.h> |
8 | #include <linux/types.h> |
9 | |
10 | /* |
11 | * Trace sequences are used to allow a function to call several other functions |
12 | * to create a string of data to use. |
13 | */ |
14 | |
15 | /** |
16 | * struct seq_buf - seq buffer structure |
17 | * @buffer: pointer to the buffer |
18 | * @size: size of the buffer |
19 | * @len: the amount of data inside the buffer |
20 | */ |
21 | struct seq_buf { |
22 | char *buffer; |
23 | size_t size; |
24 | size_t len; |
25 | }; |
26 | |
27 | #define DECLARE_SEQ_BUF(NAME, SIZE) \ |
28 | struct seq_buf NAME = { \ |
29 | .buffer = (char[SIZE]) { 0 }, \ |
30 | .size = SIZE, \ |
31 | } |
32 | |
33 | static inline void seq_buf_clear(struct seq_buf *s) |
34 | { |
35 | s->len = 0; |
36 | if (s->size) |
37 | s->buffer[0] = '\0'; |
38 | } |
39 | |
40 | static inline void |
41 | seq_buf_init(struct seq_buf *s, char *buf, unsigned int size) |
42 | { |
43 | s->buffer = buf; |
44 | s->size = size; |
45 | seq_buf_clear(s); |
46 | } |
47 | |
48 | /* |
49 | * seq_buf have a buffer that might overflow. When this happens |
50 | * len is set to be greater than size. |
51 | */ |
52 | static inline bool |
53 | seq_buf_has_overflowed(struct seq_buf *s) |
54 | { |
55 | return s->len > s->size; |
56 | } |
57 | |
58 | static inline void |
59 | seq_buf_set_overflow(struct seq_buf *s) |
60 | { |
61 | s->len = s->size + 1; |
62 | } |
63 | |
64 | /* |
65 | * How much buffer is left on the seq_buf? |
66 | */ |
67 | static inline unsigned int |
68 | seq_buf_buffer_left(struct seq_buf *s) |
69 | { |
70 | if (seq_buf_has_overflowed(s)) |
71 | return 0; |
72 | |
73 | return s->size - s->len; |
74 | } |
75 | |
76 | /* How much buffer was written? */ |
77 | static inline unsigned int seq_buf_used(struct seq_buf *s) |
78 | { |
79 | return min(s->len, s->size); |
80 | } |
81 | |
82 | /** |
83 | * seq_buf_str - get NUL-terminated C string from seq_buf |
84 | * @s: the seq_buf handle |
85 | * |
86 | * This makes sure that the buffer in @s is NUL-terminated and |
87 | * safe to read as a string. |
88 | * |
89 | * Note, if this is called when the buffer has overflowed, then |
90 | * the last byte of the buffer is zeroed, and the len will still |
91 | * point passed it. |
92 | * |
93 | * After this function is called, s->buffer is safe to use |
94 | * in string operations. |
95 | * |
96 | * Returns: @s->buf after making sure it is terminated. |
97 | */ |
98 | static inline const char *seq_buf_str(struct seq_buf *s) |
99 | { |
100 | if (WARN_ON(s->size == 0)) |
101 | return "" ; |
102 | |
103 | if (seq_buf_buffer_left(s)) |
104 | s->buffer[s->len] = 0; |
105 | else |
106 | s->buffer[s->size - 1] = 0; |
107 | |
108 | return s->buffer; |
109 | } |
110 | |
111 | /** |
112 | * seq_buf_get_buf - get buffer to write arbitrary data to |
113 | * @s: the seq_buf handle |
114 | * @bufp: the beginning of the buffer is stored here |
115 | * |
116 | * Returns: the number of bytes available in the buffer, or zero if |
117 | * there's no space. |
118 | */ |
119 | static inline size_t seq_buf_get_buf(struct seq_buf *s, char **bufp) |
120 | { |
121 | WARN_ON(s->len > s->size + 1); |
122 | |
123 | if (s->len < s->size) { |
124 | *bufp = s->buffer + s->len; |
125 | return s->size - s->len; |
126 | } |
127 | |
128 | *bufp = NULL; |
129 | return 0; |
130 | } |
131 | |
132 | /** |
133 | * seq_buf_commit - commit data to the buffer |
134 | * @s: the seq_buf handle |
135 | * @num: the number of bytes to commit |
136 | * |
137 | * Commit @num bytes of data written to a buffer previously acquired |
138 | * by seq_buf_get_buf(). To signal an error condition, or that the data |
139 | * didn't fit in the available space, pass a negative @num value. |
140 | */ |
141 | static inline void seq_buf_commit(struct seq_buf *s, int num) |
142 | { |
143 | if (num < 0) { |
144 | seq_buf_set_overflow(s); |
145 | } else { |
146 | /* num must be negative on overflow */ |
147 | BUG_ON(s->len + num > s->size); |
148 | s->len += num; |
149 | } |
150 | } |
151 | |
152 | extern __printf(2, 3) |
153 | int seq_buf_printf(struct seq_buf *s, const char *fmt, ...); |
154 | extern __printf(2, 0) |
155 | int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args); |
156 | extern int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s); |
157 | extern int seq_buf_to_user(struct seq_buf *s, char __user *ubuf, |
158 | size_t start, int cnt); |
159 | extern int seq_buf_puts(struct seq_buf *s, const char *str); |
160 | extern int seq_buf_putc(struct seq_buf *s, unsigned char c); |
161 | extern int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len); |
162 | extern int seq_buf_putmem_hex(struct seq_buf *s, const void *mem, |
163 | unsigned int len); |
164 | extern int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc); |
165 | extern int seq_buf_hex_dump(struct seq_buf *s, const char *prefix_str, |
166 | int prefix_type, int rowsize, int groupsize, |
167 | const void *buf, size_t len, bool ascii); |
168 | |
169 | #ifdef CONFIG_BINARY_PRINTF |
170 | extern int |
171 | seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary); |
172 | #endif |
173 | |
174 | void seq_buf_do_printk(struct seq_buf *s, const char *lvl); |
175 | |
176 | #endif /* _LINUX_SEQ_BUF_H */ |
177 | |