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- /* 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 */
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