path: root/kernel/trace/trace_output.c

/*
 * trace_output.c
 *
 * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
 *
 */

#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/ftrace.h>

#include "trace_output.h"

/* must be a power of 2 */
#define EVENT_HASHSIZE	128

static DECLARE_RWSEM(trace_event_mutex);

DEFINE_PER_CPU(struct trace_seq, ftrace_event_seq);

static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly;

static int next_event_type = __TRACE_LAST_TYPE + 1;

void trace_print_seq(struct seq_file *m, struct trace_seq *s)
{
	int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len;

	s->buffer[len] = 0;
	seq_puts(m, s->buffer);

	trace_seq_init(s);
}

enum print_line_t trace_print_bprintk_msg_only(struct trace_iterator *iter)
{
	struct trace_seq *s = &iter->seq;
	struct trace_entry *entry = iter->ent;
	struct bprint_entry *field;
	int ret;

	trace_assign_type(field, entry);

	ret = trace_seq_bprintf(s, field->fmt, field->buf);
	if (!ret)
		return TRACE_TYPE_PARTIAL_LINE;

	return TRACE_TYPE_HANDLED;
}

enum print_line_t trace_print_printk_msg_only(struct trace_iterator *iter)
{
	struct trace_seq *s = &iter->seq;
	struct trace_entry *entry = iter->ent;
	struct print_entry *field;
	int ret;

	trace_assign_type(field, entry);

	ret = trace_seq_printf(s, "%s", field->buf);
	if (!ret)
		return TRACE_TYPE_PARTIAL_LINE;

	return TRACE_TYPE_HANDLED;
}

/**
 * trace_seq_printf - sequence printing of trace information
 * @s: trace sequence descriptor
 * @fmt: printf format string
 *
 * The tracer may use either sequence operations or its own
 * copy to user routines. To simplify formating of a trace
 * trace_seq_printf is used to store strings into a special
 * buffer (@s). Then the output may be either used by
 * the sequencer or pulled into another buffer.
 */
int
trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
{
	int len = (PAGE_SIZE - 1) - s->len;
	va_list ap;
	int ret;

	if (!len)
		return 0;

	va_start(ap, fmt);
	ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
	va_end(ap);

	/* If we can't write it all, don't bother writing anything */
	if (ret >= len)
		return 0;

	s->len += ret;

	return len;
}
EXPORT_SYMBOL_GPL(trace_seq_printf);

int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
{
	int len = (PAGE_SIZE - 1) - s->len;
	int ret;

	if (!len)
		return 0;

	ret = bstr_printf(s->buffer + s->len, len, fmt, binary);

	/* If we can't write it all, don't bother writing anything */
	if (ret >= len)
		return 0;

	s->len += ret;

	return len;
}

/**
 * trace_seq_puts - trace sequence printing of simple string
 * @s: trace sequence descriptor
 * @str: simple string to record
 *
 * The tracer may use either the sequence operations or its own
 * copy to user routines. This function records a simple string
 * into a special buffer (@s) for later retrieval by a sequencer
 * or other mechanism.
 */
int trace_seq_puts(struct trace_seq *s, const char *str)
{
	int len = strlen(str);