Line data    Source code

       1             : /* SPDX-License-Identifier: GPL-2.0 */
       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 {
      20             :         char                    *buffer;
      21             :         size_t                  size;
      22             :         size_t                  len;
      23             :         loff_t                  readpos;
      24             : };
      25             : 
      26           0 : static inline void seq_buf_clear(struct seq_buf *s)
      27             : {
      28           0 :         s->len = 0;
      29           0 :         s->readpos = 0;
      30             : }
      31             : 
      32             : static inline void
      33           0 : seq_buf_init(struct seq_buf *s, char *buf, unsigned int size)
      34             : {
      35           0 :         s->buffer = buf;
      36           0 :         s->size = size;
      37           0 :         seq_buf_clear(s);
      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           0 : seq_buf_has_overflowed(struct seq_buf *s)
      46             : {
      47           0 :         return s->len > s->size;
      48             : }
      49             : 
      50             : static inline void
      51           0 : seq_buf_set_overflow(struct seq_buf *s)
      52             : {
      53           0 :         s->len = s->size + 1;
      54           0 : }
      55             : 
      56             : /*
      57             :  * How much buffer is left on the seq_buf?
      58             :  */
      59             : static inline unsigned int
      60           0 : seq_buf_buffer_left(struct seq_buf *s)
      61             : {
      62           0 :         if (seq_buf_has_overflowed(s))
      63             :                 return 0;
      64             : 
      65           0 :         return s->size - s->len;
      66             : }
      67             : 
      68             : /* How much buffer was written? */
      69           0 : static inline unsigned int seq_buf_used(struct seq_buf *s)
      70             : {
      71           0 :         return min(s->len, s->size);
      72             : }
      73             : 
      74             : /**
      75             :  * seq_buf_get_buf - get buffer to write arbitrary data to
      76             :  * @s: the seq_buf handle
      77             :  * @bufp: the beginning of the buffer is stored here
      78             :  *
      79             :  * Return the number of bytes available in the buffer, or zero if
      80             :  * there's no space.
      81             :  */
      82           0 : static inline size_t seq_buf_get_buf(struct seq_buf *s, char **bufp)
      83             : {
      84           0 :         WARN_ON(s->len > s->size + 1);
      85             : 
      86           0 :         if (s->len < s->size) {
      87           0 :                 *bufp = s->buffer + s->len;
      88           0 :                 return s->size - s->len;
      89             :         }
      90             : 
      91           0 :         *bufp = NULL;
      92           0 :         return 0;
      93             : }
      94             : 
      95             : /**
      96             :  * seq_buf_commit - commit data to the buffer
      97             :  * @s: the seq_buf handle
      98             :  * @num: the number of bytes to commit
      99             :  *
     100             :  * Commit @num bytes of data written to a buffer previously acquired
     101             :  * by seq_buf_get.  To signal an error condition, or that the data
     102             :  * didn't fit in the available space, pass a negative @num value.
     103             :  */
     104           0 : static inline void seq_buf_commit(struct seq_buf *s, int num)
     105             : {
     106           0 :         if (num < 0) {
     107           0 :                 seq_buf_set_overflow(s);
     108             :         } else {
     109             :                 /* num must be negative on overflow */
     110           0 :                 BUG_ON(s->len + num > s->size);
     111           0 :                 s->len += num;
     112             :         }
     113           0 : }
     114             : 
     115             : extern __printf(2, 3)
     116             : int seq_buf_printf(struct seq_buf *s, const char *fmt, ...);
     117             : extern __printf(2, 0)
     118             : int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args);
     119             : extern int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s);
     120             : extern int seq_buf_to_user(struct seq_buf *s, char __user *ubuf,
     121             :                            int cnt);
     122             : extern int seq_buf_puts(struct seq_buf *s, const char *str);
     123             : extern int seq_buf_putc(struct seq_buf *s, unsigned char c);
     124             : extern int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len);
     125             : extern int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
     126             :                               unsigned int len);
     127             : extern int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc);
     128             : extern int seq_buf_hex_dump(struct seq_buf *s, const char *prefix_str,
     129             :                             int prefix_type, int rowsize, int groupsize,
     130             :                             const void *buf, size_t len, bool ascii);
     131             : 
     132             : #ifdef CONFIG_BINARY_PRINTF
     133             : extern int
     134             : seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary);
     135             : #endif
     136             : 
     137             : #endif /* _LINUX_SEQ_BUF_H */