LXR linux/include/linux/trace

   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