[linux-block.git] / include / linux / seq_buf.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_SEQ_BUF_H
#define _LINUX_SEQ_BUF_H

#include <linux/fs.h>

/*
 * Trace sequences are used to allow a function to call several other functions
 * to create a string of data to use.
 */

/**
 * seq_buf - seq buffer structure
 * @buffer:	pointer to the buffer
 * @size:	size of the buffer
 * @len:	the amount of data inside the buffer
 * @readpos:	The next position to read in the buffer.
 */
struct seq_buf {
	char			*buffer;
	size_t			size;
	size_t			len;
	loff_t			readpos;
};

static inline void seq_buf_clear(struct seq_buf *s)
{
	s->len = 0;
	s->readpos = 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
 * the len and size are set to be equal.
 */
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_terminate - Make sure buffer is nul terminated
 * @s: the seq_buf descriptor to terminate.
 *
 * 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.
 */
static inline void seq_buf_terminate(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;
}

/**
 * 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
 *
 * Return 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.  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,
			   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

#endif /* _LINUX_SEQ_BUF_H */
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
3a161d99 SRRH	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	* @readpos: The next position to read in the buffer.
	18	*/
	19	struct seq_buf {
9a777793 SRRH	20	char *buffer;
	21	size_t size;
	22	size_t len;
	23	loff_t readpos;
3a161d99 SRRH	24	};
3a161d99 SRRH	25
0736c033 SRRH	26	static inline void seq_buf_clear(struct seq_buf *s)
	27	{
	28	s->len = 0;
	29	s->readpos = 0;
	30	}
	31
3a161d99	32	static inline void
d9a9280a	33	seq_buf_init(struct seq_buf s, char buf, unsigned int size)
3a161d99 SRRH	34	{
	35	s->buffer = buf;
	36	s->size = size;
0736c033	37	seq_buf_clear(s);
3a161d99 SRRH	38	}
	39
	40	/*
	41	* seq_buf have a buffer that might overflow. When this happens
	42	* the len and size are set to be equal.
	43	*/
	44	static inline bool
	45	seq_buf_has_overflowed(struct seq_buf *s)
	46	{
8cd709ae	47	return s->len > s->size;
3a161d99 SRRH	48	}
	49
	50	static inline void
	51	seq_buf_set_overflow(struct seq_buf *s)
	52	{
8cd709ae	53	s->len = s->size + 1;
3a161d99 SRRH	54	}
	55
	56	/*
	57	* How much buffer is left on the seq_buf?
	58	*/
	59	static inline unsigned int
	60	seq_buf_buffer_left(struct seq_buf *s)
	61	{
	62	if (seq_buf_has_overflowed(s))
	63	return 0;
	64
8cd709ae	65	return s->size - s->len;
3a161d99 SRRH	66	}
3a161d99 SRRH	67
eeab9815 SRRH	68	/* How much buffer was written? */
	69	static inline unsigned int seq_buf_used(struct seq_buf *s)
	70	{
	71	return min(s->len, s->size);
	72	}
	73
f2616c77 SRV	74	/**
	75	* seq_buf_terminate - Make sure buffer is nul terminated
	76	* @s: the seq_buf descriptor to terminate.
	77	*
	78	* This makes sure that the buffer in @s is nul terminated and
	79	* safe to read as a string.
	80	*
	81	* Note, if this is called when the buffer has overflowed, then
	82	* the last byte of the buffer is zeroed, and the len will still
	83	* point passed it.
	84	*
	85	* After this function is called, s->buffer is safe to use
	86	* in string operations.
	87	*/
	88	static inline void seq_buf_terminate(struct seq_buf *s)
	89	{
	90	if (WARN_ON(s->size == 0))
	91	return;
	92
	93	if (seq_buf_buffer_left(s))
	94	s->buffer[s->len] = 0;
	95	else
	96	s->buffer[s->size - 1] = 0;
	97	}
	98
01cb06a4 SRRH	99	/**
	100	* seq_buf_get_buf - get buffer to write arbitrary data to
	101	* @s: the seq_buf handle
	102	* @bufp: the beginning of the buffer is stored here
	103	*
	104	* Return the number of bytes available in the buffer, or zero if
	105	* there's no space.
	106	*/
	107	static inline size_t seq_buf_get_buf(struct seq_buf s, char *bufp)
	108	{
	109	WARN_ON(s->len > s->size + 1);
	110
	111	if (s->len < s->size) {
	112	*bufp = s->buffer + s->len;
	113	return s->size - s->len;
	114	}
	115
	116	*bufp = NULL;
	117	return 0;
	118	}
	119
	120	/**
	121	* seq_buf_commit - commit data to the buffer
	122	* @s: the seq_buf handle
	123	* @num: the number of bytes to commit
	124	*
	125	* Commit @num bytes of data written to a buffer previously acquired
	126	* by seq_buf_get. To signal an error condition, or that the data
	127	* didn't fit in the available space, pass a negative @num value.
	128	*/
	129	static inline void seq_buf_commit(struct seq_buf *s, int num)
	130	{
	131	if (num < 0) {
	132	seq_buf_set_overflow(s);
	133	} else {
	134	/* num must be negative on overflow */
	135	BUG_ON(s->len + num > s->size);
	136	s->len += num;
	137	}
	138	}
	139
3a161d99 SRRH	140	extern __printf(2, 3)
	141	int seq_buf_printf(struct seq_buf s, const char fmt, ...);
	142	extern __printf(2, 0)
	143	int seq_buf_vprintf(struct seq_buf s, const char fmt, va_list args);
3a161d99 SRRH	144	extern int seq_buf_print_seq(struct seq_file m, struct seq_buf s);
	145	extern int seq_buf_to_user(struct seq_buf s, char __user ubuf,
	146	int cnt);
	147	extern int seq_buf_puts(struct seq_buf s, const char str);
	148	extern int seq_buf_putc(struct seq_buf *s, unsigned char c);
	149	extern int seq_buf_putmem(struct seq_buf s, const void mem, unsigned int len);
	150	extern int seq_buf_putmem_hex(struct seq_buf s, const void mem,
	151	unsigned int len);
dd23180a	152	extern int seq_buf_path(struct seq_buf s, const struct path path, const char *esc);
353cade3 PM	153	extern int seq_buf_hex_dump(struct seq_buf s, const char prefix_str,
	154	int prefix_type, int rowsize, int groupsize,
	155	const void *buf, size_t len, bool ascii);
3a161d99	156
2448913e SRRH	157	#ifdef CONFIG_BINARY_PRINTF
	158	extern int
	159	seq_buf_bprintf(struct seq_buf s, const char fmt, const u32 *binary);
	160	#endif
	161
3a161d99	162	#endif /* _LINUX_SEQ_BUF_H */