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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_SEQ_BUF_H
#define _LINUX_SEQ_BUF_H
#include <linux/bug.h>
#include <linux/minmax.h>
#include <linux/seq_file.h>
#include <linux/types.h>
/*
* Trace sequences are used to allow a function to call several other functions
* to create a string of data to use.
*/
/**
* struct seq_buf - seq buffer structure
* @buffer: pointer to the buffer
* @size: size of the buffer
* @len: the amount of data inside the buffer
*/
struct seq_buf {
char *buffer;
size_t size;
size_t len;
};
#define DECLARE_SEQ_BUF(NAME, SIZE) \
struct seq_buf NAME = { \
.buffer = (char[SIZE]) { 0 }, \
.size = SIZE, \
}
static inline void seq_buf_clear(struct seq_buf *s)
{
s->len = 0;
if (s->size)
s->buffer[0] = '\0';
}
static inline void
seq_buf_init(struct seq_buf *s, char *buf, unsigned int size)
{
s->buffer = buf;
s->size = size;
seq_buf_clear(s);
}
/*
* seq_buf have a buffer that might overflow. When this happens
* len is set to be greater than size.
*/
static inline bool
seq_buf_has_overflowed(struct seq_buf *s)
{
return s->len > s->size;
}
static inline void
seq_buf_set_overflow(struct seq_buf *s)
{
s->len = s->size + 1;
}
/*
* How much buffer is left on the seq_buf?
*/
static inline unsigned int
seq_buf_buffer_left(struct seq_buf *s)
{
if (seq_buf_has_overflowed(s))
return 0;
return s->size - s->len;
}
/* How much buffer was written? */
static inline unsigned int seq_buf_used(struct seq_buf *s)
{
return min(s->len, s->size);
}
/**
* seq_buf_str - get NUL-terminated C string from seq_buf
* @s: the seq_buf handle
*
* This makes sure that the buffer in @s is NUL-terminated and
* safe to read as a string.
*
* Note, if this is called when the buffer has overflowed, then
* the last byte of the buffer is zeroed, and the len will still
* point passed it.
*
* After this function is called, s->buffer is safe to use
* in string operations.
*
* Returns: @s->buf after making sure it is terminated.
*/
static inline const char *seq_buf_str(struct seq_buf *s)
{
if (WARN_ON(s->size == 0))
return "";
if (seq_buf_buffer_left(s))
s->buffer[s->len] = 0;
else
s->buffer[s->size - 1] = 0;
return s->buffer;
}
/**
* seq_buf_get_buf - get buffer to write arbitrary data to
* @s: the seq_buf handle
* @bufp: the beginning of the buffer is stored here
*
* Returns: the number of bytes available in the buffer, or zero if
* there's no space.
*/
static inline size_t seq_buf_get_buf(struct seq_buf *s, char **bufp)
{
WARN_ON(s->len > s->size + 1);
if (s->len < s->size) {
*bufp = s->buffer + s->len;
return s->size - s->len;
}
*bufp = NULL;
return 0;
}
/**
* seq_buf_commit - commit data to the buffer
* @s: the seq_buf handle
* @num: the number of bytes to commit
*
* Commit @num bytes of data written to a buffer previously acquired
* by seq_buf_get_buf(). To signal an error condition, or that the data
* didn't fit in the available space, pass a negative @num value.
*/
static inline void seq_buf_commit(struct seq_buf *s, int num)
{
if (num < 0) {
seq_buf_set_overflow(s);
} else {
/* num must be negative on overflow */
BUG_ON(s->len + num > s->size);
s->len += num;
}
}
extern __printf(2, 3)
int seq_buf_printf(struct seq_buf *s, const char *fmt, ...);
extern __printf(2, 0)
int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args);
extern int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s);
extern int seq_buf_to_user(struct seq_buf *s, char __user *ubuf,
size_t start, int cnt);
extern int seq_buf_puts(struct seq_buf *s, const char *str);
extern int seq_buf_putc(struct seq_buf *s, unsigned char c);
extern int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len);
extern int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
unsigned int len);
extern int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc);
extern int seq_buf_hex_dump(struct seq_buf *s, const char *prefix_str,
int prefix_type, int rowsize, int groupsize,
const void *buf, size_t len, bool ascii);
#ifdef CONFIG_BINARY_PRINTF
extern int
seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary);
#endif
void seq_buf_do_printk(struct seq_buf *s, const char *lvl);
#endif /* _LINUX_SEQ_BUF_H */
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