1 #ifndef _LINUX_SEQ_BUF_H 2 #define _LINUX_SEQ_BUF_H 3 4 #include <linux/fs.h> 5 6 /* 7 * Trace sequences are used to allow a function to call several other functions 8 * to create a string of data to use. 9 */ 10 11 /** 12 * seq_buf - seq buffer structure 13 * @buffer: pointer to the buffer 14 * @size: size of the buffer 15 * @len: the amount of data inside the buffer 16 * @readpos: The next position to read in the buffer. 17 */ 18 struct seq_buf { 19 char *buffer; 20 size_t size; 21 size_t len; 22 loff_t readpos; 23 }; 24 25 static inline void seq_buf_clear(struct seq_buf *s) 26 { 27 s->len = 0; 28 s->readpos = 0; 29 } 30 31 static inline void 32 seq_buf_init(struct seq_buf *s, unsigned char *buf, unsigned int size) 33 { 34 s->buffer = buf; 35 s->size = size; 36 seq_buf_clear(s); 37 } 38 39 /* 40 * seq_buf have a buffer that might overflow. When this happens 41 * the len and size are set to be equal. 42 */ 43 static inline bool 44 seq_buf_has_overflowed(struct seq_buf *s) 45 { 46 return s->len > s->size; 47 } 48 49 static inline void 50 seq_buf_set_overflow(struct seq_buf *s) 51 { 52 s->len = s->size + 1; 53 } 54 55 /* 56 * How much buffer is left on the seq_buf? 57 */ 58 static inline unsigned int 59 seq_buf_buffer_left(struct seq_buf *s) 60 { 61 if (seq_buf_has_overflowed(s)) 62 return 0; 63 64 return s->size - s->len; 65 } 66 67 /* How much buffer was written? */ 68 static inline unsigned int seq_buf_used(struct seq_buf *s) 69 { 70 return min(s->len, s->size); 71 } 72 73 /** 74 * seq_buf_get_buf - get buffer to write arbitrary data to 75 * @s: the seq_buf handle 76 * @bufp: the beginning of the buffer is stored here 77 * 78 * Return the number of bytes available in the buffer, or zero if 79 * there's no space. 80 */ 81 static inline size_t seq_buf_get_buf(struct seq_buf *s, char **bufp) 82 { 83 WARN_ON(s->len > s->size + 1); 84 85 if (s->len < s->size) { 86 *bufp = s->buffer + s->len; 87 return s->size - s->len; 88 } 89 90 *bufp = NULL; 91 return 0; 92 } 93 94 /** 95 * seq_buf_commit - commit data to the buffer 96 * @s: the seq_buf handle 97 * @num: the number of bytes to commit 98 * 99 * Commit @num bytes of data written to a buffer previously acquired 100 * by seq_buf_get. To signal an error condition, or that the data 101 * didn't fit in the available space, pass a negative @num value. 102 */ 103 static inline void seq_buf_commit(struct seq_buf *s, int num) 104 { 105 if (num < 0) { 106 seq_buf_set_overflow(s); 107 } else { 108 /* num must be negative on overflow */ 109 BUG_ON(s->len + num > s->size); 110 s->len += num; 111 } 112 } 113 114 extern __printf(2, 3) 115 int seq_buf_printf(struct seq_buf *s, const char *fmt, ...); 116 extern __printf(2, 0) 117 int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args); 118 extern int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s); 119 extern int seq_buf_to_user(struct seq_buf *s, char __user *ubuf, 120 int cnt); 121 extern int seq_buf_puts(struct seq_buf *s, const char *str); 122 extern int seq_buf_putc(struct seq_buf *s, unsigned char c); 123 extern int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len); 124 extern int seq_buf_putmem_hex(struct seq_buf *s, const void *mem, 125 unsigned int len); 126 extern int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc); 127 128 #ifdef CONFIG_BINARY_PRINTF 129 extern int 130 seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary); 131 #endif 132 133 #endif /* _LINUX_SEQ_BUF_H */ 134