Line data    Source code

       1             : /* SPDX-License-Identifier: GPL-2.0 */
       2             : #ifndef _LINUX_TRACE_SEQ_H
       3             : #define _LINUX_TRACE_SEQ_H
       4             : 
       5             : #include <linux/seq_buf.h>
       6             : 
       7             : #include <asm/page.h>
       8             : 
       9             : /*
      10             :  * Trace sequences are used to allow a function to call several other functions
      11             :  * to create a string of data to use (up to a max of PAGE_SIZE).
      12             :  */
      13             : 
      14             : struct trace_seq {
      15             :         char                    buffer[PAGE_SIZE];
      16             :         struct seq_buf          seq;
      17             :         int                     full;
      18             : };
      19             : 
      20             : static inline void
      21           0 : trace_seq_init(struct trace_seq *s)
      22             : {
      23           0 :         seq_buf_init(&s->seq, s->buffer, PAGE_SIZE);
      24           0 :         s->full = 0;
      25           0 : }
      26             : 
      27             : /**
      28             :  * trace_seq_used - amount of actual data written to buffer
      29             :  * @s: trace sequence descriptor
      30             :  *
      31             :  * Returns the amount of data written to the buffer.
      32             :  *
      33             :  * IMPORTANT!
      34             :  *
      35             :  * Use this instead of @s->seq.len if you need to pass the amount
      36             :  * of data from the buffer to another buffer (userspace, or what not).
      37             :  * The @s->seq.len on overflow is bigger than the buffer size and
      38             :  * using it can cause access to undefined memory.
      39             :  */
      40           0 : static inline int trace_seq_used(struct trace_seq *s)
      41             : {
      42           0 :         return seq_buf_used(&s->seq);
      43             : }
      44             : 
      45             : /**
      46             :  * trace_seq_buffer_ptr - return pointer to next location in buffer
      47             :  * @s: trace sequence descriptor
      48             :  *
      49             :  * Returns the pointer to the buffer where the next write to
      50             :  * the buffer will happen. This is useful to save the location
      51             :  * that is about to be written to and then return the result
      52             :  * of that write.
      53             :  */
      54             : static inline char *
      55           0 : trace_seq_buffer_ptr(struct trace_seq *s)
      56             : {
      57           0 :         return s->buffer + seq_buf_used(&s->seq);
      58             : }
      59             : 
      60             : /**
      61             :  * trace_seq_has_overflowed - return true if the trace_seq took too much
      62             :  * @s: trace sequence descriptor
      63             :  *
      64             :  * Returns true if too much data was added to the trace_seq and it is
      65             :  * now full and will not take anymore.
      66             :  */
      67           0 : static inline bool trace_seq_has_overflowed(struct trace_seq *s)
      68             : {
      69           0 :         return s->full || seq_buf_has_overflowed(&s->seq);
      70             : }
      71             : 
      72             : /*
      73             :  * Currently only defined when tracing is enabled.
      74             :  */
      75             : #ifdef CONFIG_TRACING
      76             : extern __printf(2, 3)
      77             : void trace_seq_printf(struct trace_seq *s, const char *fmt, ...);
      78             : extern __printf(2, 0)
      79             : void trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args);
      80             : extern void
      81             : trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary);
      82             : extern int trace_print_seq(struct seq_file *m, struct trace_seq *s);
      83             : extern int trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
      84             :                              int cnt);
      85             : extern void trace_seq_puts(struct trace_seq *s, const char *str);
      86             : extern void trace_seq_putc(struct trace_seq *s, unsigned char c);
      87             : extern void trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len);
      88             : extern void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
      89             :                                 unsigned int len);
      90             : extern int trace_seq_path(struct trace_seq *s, const struct path *path);
      91             : 
      92             : extern void trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
      93             :                              int nmaskbits);
      94             : 
      95             : extern int trace_seq_hex_dump(struct trace_seq *s, const char *prefix_str,
      96             :                               int prefix_type, int rowsize, int groupsize,
      97             :                               const void *buf, size_t len, bool ascii);
      98             : 
      99             : #else /* CONFIG_TRACING */
     100             : static inline void trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
     101             : {
     102             : }
     103             : static inline void
     104             : trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
     105             : {
     106             : }
     107             : 
     108             : static inline void
     109             : trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
     110             :                   int nmaskbits)
     111             : {
     112             : }
     113             : 
     114             : static inline int trace_print_seq(struct seq_file *m, struct trace_seq *s)
     115             : {
     116             :         return 0;
     117             : }
     118             : static inline int trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
     119             :                                     int cnt)
     120             : {
     121             :         return 0;
     122             : }
     123             : static inline void trace_seq_puts(struct trace_seq *s, const char *str)
     124             : {
     125             : }
     126             : static inline void trace_seq_putc(struct trace_seq *s, unsigned char c)
     127             : {
     128             : }
     129             : static inline void
     130             : trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len)
     131             : {
     132             : }
     133             : static inline void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
     134             :                                        unsigned int len)
     135             : {
     136             : }
     137             : static inline int trace_seq_path(struct trace_seq *s, const struct path *path)
     138             : {
     139             :         return 0;
     140             : }
     141             : #endif /* CONFIG_TRACING */
     142             : 
     143             : #endif /* _LINUX_TRACE_SEQ_H */