Linux kernel mirror (for testing)
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linux
1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_TRACE_SEQ_H
3#define _LINUX_TRACE_SEQ_H
4
5#include <linux/seq_buf.h>
6
7#include <asm/page.h>
8
9/*
10 * Trace sequences are used to allow a function to call several other functions
11 * to create a string of data to use.
12 */
13
14#define TRACE_SEQ_BUFFER_SIZE (PAGE_SIZE * 2 - \
15 (sizeof(struct seq_buf) + sizeof(size_t) + sizeof(int)))
16
17struct trace_seq {
18 char buffer[TRACE_SEQ_BUFFER_SIZE];
19 struct seq_buf seq;
20 size_t readpos;
21 int full;
22};
23
24static inline void
25trace_seq_init(struct trace_seq *s)
26{
27 seq_buf_init(&s->seq, s->buffer, TRACE_SEQ_BUFFER_SIZE);
28 s->full = 0;
29 s->readpos = 0;
30}
31
32/**
33 * trace_seq_used - amount of actual data written to buffer
34 * @s: trace sequence descriptor
35 *
36 * Returns the amount of data written to the buffer.
37 *
38 * IMPORTANT!
39 *
40 * Use this instead of @s->seq.len if you need to pass the amount
41 * of data from the buffer to another buffer (userspace, or what not).
42 * The @s->seq.len on overflow is bigger than the buffer size and
43 * using it can cause access to undefined memory.
44 */
45static inline int trace_seq_used(struct trace_seq *s)
46{
47 return seq_buf_used(&s->seq);
48}
49
50/**
51 * trace_seq_buffer_ptr - return pointer to next location in buffer
52 * @s: trace sequence descriptor
53 *
54 * Returns the pointer to the buffer where the next write to
55 * the buffer will happen. This is useful to save the location
56 * that is about to be written to and then return the result
57 * of that write.
58 */
59static inline char *
60trace_seq_buffer_ptr(struct trace_seq *s)
61{
62 return s->buffer + seq_buf_used(&s->seq);
63}
64
65/**
66 * trace_seq_has_overflowed - return true if the trace_seq took too much
67 * @s: trace sequence descriptor
68 *
69 * Returns true if too much data was added to the trace_seq and it is
70 * now full and will not take anymore.
71 */
72static inline bool trace_seq_has_overflowed(struct trace_seq *s)
73{
74 return s->full || seq_buf_has_overflowed(&s->seq);
75}
76
77/*
78 * Currently only defined when tracing is enabled.
79 */
80#ifdef CONFIG_TRACING
81extern __printf(2, 3)
82void trace_seq_printf(struct trace_seq *s, const char *fmt, ...);
83extern __printf(2, 0)
84void trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args);
85extern void
86trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary);
87extern int trace_print_seq(struct seq_file *m, struct trace_seq *s);
88extern int trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
89 int cnt);
90extern void trace_seq_puts(struct trace_seq *s, const char *str);
91extern void trace_seq_putc(struct trace_seq *s, unsigned char c);
92extern void trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len);
93extern void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
94 unsigned int len);
95extern int trace_seq_path(struct trace_seq *s, const struct path *path);
96
97extern void trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
98 int nmaskbits);
99
100extern int trace_seq_hex_dump(struct trace_seq *s, const char *prefix_str,
101 int prefix_type, int rowsize, int groupsize,
102 const void *buf, size_t len, bool ascii);
103char *trace_seq_acquire(struct trace_seq *s, unsigned int len);
104
105#else /* CONFIG_TRACING */
106static inline __printf(2, 3)
107void trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
108{
109}
110static inline void
111trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
112{
113}
114
115static inline void
116trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
117 int nmaskbits)
118{
119}
120
121static inline int trace_print_seq(struct seq_file *m, struct trace_seq *s)
122{
123 return 0;
124}
125static inline int trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
126 int cnt)
127{
128 return 0;
129}
130static inline void trace_seq_puts(struct trace_seq *s, const char *str)
131{
132}
133static inline void trace_seq_putc(struct trace_seq *s, unsigned char c)
134{
135}
136static inline void
137trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len)
138{
139}
140static inline void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
141 unsigned int len)
142{
143}
144static inline int trace_seq_path(struct trace_seq *s, const struct path *path)
145{
146 return 0;
147}
148static inline char *trace_seq_acquire(struct trace_seq *s, unsigned int len)
149{
150 return NULL;
151}
152#endif /* CONFIG_TRACING */
153
154#endif /* _LINUX_TRACE_SEQ_H */