include/linux/trace_seq.h

   1 #ifndef _LINUX_TRACE_SEQ_H
   2 #define _LINUX_TRACE_SEQ_H
   3
   4 #include <linux/fs.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
  13 struct trace_seq {
  14         unsigned char           buffer[PAGE_SIZE];
  15         unsigned int            len;
  16         unsigned int            readpos;
  17         int                     full;
  18 };
  19
  20 static inline void
  21 trace_seq_init(struct trace_seq *s)
  22 {
  23         s->len = 0;
  24         s->readpos = 0;
  25         s->full = 0;
  26 }
  27
  28 /**
  29  * trace_seq_buffer_ptr - return pointer to next location in buffer
  30  * @s: trace sequence descriptor
  31  *
  32  * Returns the pointer to the buffer where the next write to
  33  * the buffer will happen. This is useful to save the location
  34  * that is about to be written to and then return the result
  35  * of that write.
  36  */
  37 static inline unsigned char *
  38 trace_seq_buffer_ptr(struct trace_seq *s)
  39 {
  40         return s->buffer + s->len;
  41 }
  42
  43 /**
  44  * trace_seq_has_overflowed - return true if the trace_seq took too much
  45  * @s: trace sequence descriptor
  46  *
  47  * Returns true if too much data was added to the trace_seq and it is
  48  * now full and will not take anymore.
  49  */
  50 static inline bool trace_seq_has_overflowed(struct trace_seq *s)
  51 {
  52         return s->full || s->len > PAGE_SIZE - 1;
  53 }
  54
  55 /*
  56  * Currently only defined when tracing is enabled.
  57  */
  58 #ifdef CONFIG_TRACING
  59 extern __printf(2, 3)
  60 int trace_seq_printf(struct trace_seq *s, const char *fmt, ...);
  61 extern __printf(2, 0)
  62 int trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args);
  63 extern int
  64 trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary);
  65 extern int trace_print_seq(struct seq_file *m, struct trace_seq *s);
  66 extern int trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
  67                              int cnt);
  68 extern int trace_seq_puts(struct trace_seq *s, const char *str);
  69 extern int trace_seq_putc(struct trace_seq *s, unsigned char c);
  70 extern int trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len);
  71 extern int trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
  72                                 unsigned int len);
  73 extern int trace_seq_path(struct trace_seq *s, const struct path *path);
  74
  75 extern int trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
  76                              int nmaskbits);
  77
  78 #else /* CONFIG_TRACING */
  79 static inline int trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
  80 {
  81         return 0;
  82 }
  83 static inline int
  84 trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
  85 {
  86         return 0;
  87 }
  88
  89 static inline int
  90 trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
  91                   int nmaskbits)
  92 {
  93         return 0;
  94 }
  95
  96 static inline int trace_print_seq(struct seq_file *m, struct trace_seq *s)
  97 {
  98         return 0;
  99 }
 100 static inline int trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
 101                                     int cnt)
 102 {
 103         return 0;
 104 }
 105 static inline int trace_seq_puts(struct trace_seq *s, const char *str)
 106 {
 107         return 0;
 108 }
 109 static inline int trace_seq_putc(struct trace_seq *s, unsigned char c)
 110 {
 111         return 0;
 112 }
 113 static inline int
 114 trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len)
 115 {
 116         return 0;
 117 }
 118 static inline int trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
 119                                        unsigned int len)
 120 {
 121         return 0;
 122 }
 123 static inline int trace_seq_path(struct trace_seq *s, const struct path *path)
 124 {
 125         return 0;
 126 }
 127 #endif /* CONFIG_TRACING */
 128
 129 #endif /* _LINUX_TRACE_SEQ_H */