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