1#ifndef _LINUX_TRACE_SEQ_H 2#define _LINUX_TRACE_SEQ_H 3 4#include <linux/seq_buf.h> 5 6#include <asm/page.h> 7 8/* 9 * Trace sequences are used to allow a function to call several other functions 10 * to create a string of data to use (up to a max of PAGE_SIZE). 11 */ 12 13struct trace_seq { 14 unsigned char buffer[PAGE_SIZE]; 15 struct seq_buf seq; 16 int full; 17}; 18 19static inline void 20trace_seq_init(struct trace_seq *s) 21{ 22 seq_buf_init(&s->seq, s->buffer, PAGE_SIZE); 23 s->full = 0; 24} 25 26/** 27 * trace_seq_used - amount of actual data written to buffer 28 * @s: trace sequence descriptor 29 * 30 * Returns the amount of data written to the buffer. 31 * 32 * IMPORTANT! 33 * 34 * Use this instead of @s->seq.len if you need to pass the amount 35 * of data from the buffer to another buffer (userspace, or what not). 36 * The @s->seq.len on overflow is bigger than the buffer size and 37 * using it can cause access to undefined memory. 38 */ 39static inline int trace_seq_used(struct trace_seq *s) 40{ 41 return seq_buf_used(&s->seq); 42} 43 44/** 45 * trace_seq_buffer_ptr - return pointer to next location in buffer 46 * @s: trace sequence descriptor 47 * 48 * Returns the pointer to the buffer where the next write to 49 * the buffer will happen. This is useful to save the location 50 * that is about to be written to and then return the result 51 * of that write. 52 */ 53static inline unsigned char * 54trace_seq_buffer_ptr(struct trace_seq *s) 55{ 56 return s->buffer + seq_buf_used(&s->seq); 57} 58 59/** 60 * trace_seq_has_overflowed - return true if the trace_seq took too much 61 * @s: trace sequence descriptor 62 * 63 * Returns true if too much data was added to the trace_seq and it is 64 * now full and will not take anymore. 65 */ 66static inline bool trace_seq_has_overflowed(struct trace_seq *s) 67{ 68 return s->full || seq_buf_has_overflowed(&s->seq); 69} 70 71/* 72 * Currently only defined when tracing is enabled. 73 */ 74#ifdef CONFIG_TRACING 75extern __printf(2, 3) 76void trace_seq_printf(struct trace_seq *s, const char *fmt, ...); 77extern __printf(2, 0) 78void trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args); 79extern void 80trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary); 81extern int trace_print_seq(struct seq_file *m, struct trace_seq *s); 82extern int trace_seq_to_user(struct trace_seq *s, char __user *ubuf, 83 int cnt); 84extern void trace_seq_puts(struct trace_seq *s, const char *str); 85extern void trace_seq_putc(struct trace_seq *s, unsigned char c); 86extern void trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len); 87extern void trace_seq_putmem_hex(struct trace_seq *s, const void *mem, 88 unsigned int len); 89extern int trace_seq_path(struct trace_seq *s, const struct path *path); 90 91extern void trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp, 92 int nmaskbits); 93 94#else /* CONFIG_TRACING */ 95static inline void trace_seq_printf(struct trace_seq *s, const char *fmt, ...) 96{ 97} 98static inline void 99trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary) 100{ 101} 102 103static inline void 104trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp, 105 int nmaskbits) 106{ 107} 108 109static inline int trace_print_seq(struct seq_file *m, struct trace_seq *s) 110{ 111 return 0; 112} 113static inline int trace_seq_to_user(struct trace_seq *s, char __user *ubuf, 114 int cnt) 115{ 116 return 0; 117} 118static inline void trace_seq_puts(struct trace_seq *s, const char *str) 119{ 120} 121static inline void trace_seq_putc(struct trace_seq *s, unsigned char c) 122{ 123} 124static inline void 125trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len) 126{ 127} 128static inline void trace_seq_putmem_hex(struct trace_seq *s, const void *mem, 129 unsigned int len) 130{ 131} 132static inline int trace_seq_path(struct trace_seq *s, const struct path *path) 133{ 134 return 0; 135} 136#endif /* CONFIG_TRACING */ 137 138#endif /* _LINUX_TRACE_SEQ_H */ 139