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 13 struct trace_seq { 14 unsigned char buffer[PAGE_SIZE]; 15 struct seq_buf seq; 16 int full; 17 }; 18 19 static inline void 20 trace_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 */ 39 static 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 */ 53 static inline unsigned char * 54 trace_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 */ 66 static 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 75 extern __printf(2, 3) 76 void trace_seq_printf(struct trace_seq *s, const char *fmt, ...); 77 extern __printf(2, 0) 78 void trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args); 79 extern void 80 trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary); 81 extern int trace_print_seq(struct seq_file *m, struct trace_seq *s); 82 extern int trace_seq_to_user(struct trace_seq *s, char __user *ubuf, 83 int cnt); 84 extern void trace_seq_puts(struct trace_seq *s, const char *str); 85 extern void trace_seq_putc(struct trace_seq *s, unsigned char c); 86 extern void trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len); 87 extern void trace_seq_putmem_hex(struct trace_seq *s, const void *mem, 88 unsigned int len); 89 extern int trace_seq_path(struct trace_seq *s, const struct path *path); 90 91 extern void trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp, 92 int nmaskbits); 93 94 #else /* CONFIG_TRACING */ 95 static inline void trace_seq_printf(struct trace_seq *s, const char *fmt, ...) 96 { 97 } 98 static inline void 99 trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary) 100 { 101 } 102 103 static inline void 104 trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp, 105 int nmaskbits) 106 { 107 } 108 109 static inline int trace_print_seq(struct seq_file *m, struct trace_seq *s) 110 { 111 return 0; 112 } 113 static inline int trace_seq_to_user(struct trace_seq *s, char __user *ubuf, 114 int cnt) 115 { 116 return 0; 117 } 118 static inline void trace_seq_puts(struct trace_seq *s, const char *str) 119 { 120 } 121 static inline void trace_seq_putc(struct trace_seq *s, unsigned char c) 122 { 123 } 124 static inline void 125 trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len) 126 { 127 } 128 static inline void trace_seq_putmem_hex(struct trace_seq *s, const void *mem, 129 unsigned int len) 130 { 131 } 132 static 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