include/linux/trace_seq.h

Source file repositories/reference/linux-study-clean/include/linux/trace_seq.h

File Facts

System
Linux kernel
Corpus path
include/linux/trace_seq.h
Extension
.h
Size
5177 bytes
Lines
184
Domain
Core OS
Bucket
Core Kernel Interface
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

struct trace_seq {
	struct seq_buf		seq;
	size_t			readpos;
	int			full;
	char                    buffer[TRACE_SEQ_BUFFER_SIZE];
};

static inline void
trace_seq_init(struct trace_seq *s)
{
	seq_buf_init(&s->seq, s->buffer, TRACE_SEQ_BUFFER_SIZE);
	s->full = 0;
	s->readpos = 0;
}

/**
 * trace_seq_used - amount of actual data written to buffer
 * @s: trace sequence descriptor
 *
 * Returns the amount of data written to the buffer.
 *
 * IMPORTANT!
 *
 * Use this instead of @s->seq.len if you need to pass the amount
 * of data from the buffer to another buffer (userspace, or what not).
 * The @s->seq.len on overflow is bigger than the buffer size and
 * using it can cause access to undefined memory.
 */
static inline int trace_seq_used(struct trace_seq *s)
{
	return seq_buf_used(&s->seq);
}

/**
 * trace_seq_buffer_ptr - return pointer to next location in buffer
 * @s: trace sequence descriptor
 *
 * Returns the pointer to the buffer where the next write to
 * the buffer will happen. This is useful to save the location
 * that is about to be written to and then return the result
 * of that write.
 */
static inline char *
trace_seq_buffer_ptr(struct trace_seq *s)
{
	return s->buffer + seq_buf_used(&s->seq);
}

/**
 * trace_seq_has_overflowed - return true if the trace_seq took too much
 * @s: trace sequence descriptor
 *
 * Returns true if too much data was added to the trace_seq and it is
 * now full and will not take anymore.
 */
static inline bool trace_seq_has_overflowed(struct trace_seq *s)
{
	return s->full || seq_buf_has_overflowed(&s->seq);
}

/**
 * trace_seq_pop - pop off the last written character
 * @s: trace sequence descriptor
 *
 * Removes the last written character to the trace_seq @s.
 *
 * Returns the last character or -1 if it is empty.
 */
static inline int trace_seq_pop(struct trace_seq *s)
{
	return seq_buf_pop(&s->seq);
}

/*
 * Currently only defined when tracing is enabled.
 */
#ifdef CONFIG_TRACING
extern __printf(2, 3)
void trace_seq_printf(struct trace_seq *s, const char *fmt, ...);
extern __printf(2, 0)
void trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args);
extern __printf(2, 0)
void trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary);
extern int trace_print_seq(struct seq_file *m, struct trace_seq *s);
extern int trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
			     int cnt);
extern void trace_seq_puts(struct trace_seq *s, const char *str);
extern void trace_seq_putc(struct trace_seq *s, unsigned char c);
extern void trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len);
extern void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,

Annotation

Implementation Notes