path: root/tools/lib/traceevent/kbuffer-parse.c

// SPDX-License-Identifier: LGPL-2.1
/*
 * Copyright (C) 2009, 2010 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
 *
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "kbuffer.h"

#define MISSING_EVENTS (1UL << 31)
#define MISSING_STORED (1UL << 30)

#define COMMIT_MASK ((1 << 27) - 1)

enum {
	KBUFFER_FL_HOST_BIG_ENDIAN	= (1<<0),
	KBUFFER_FL_BIG_ENDIAN		= (1<<1),
	KBUFFER_FL_LONG_8		= (1<<2),
	KBUFFER_FL_OLD_FORMAT		= (1<<3),
};

#define ENDIAN_MASK (KBUFFER_FL_HOST_BIG_ENDIAN | KBUFFER_FL_BIG_ENDIAN)

/** kbuffer
 * @timestamp		- timestamp of current event
 * @lost_events		- # of lost events between this subbuffer and previous
 * @flags		- special flags of the kbuffer
 * @subbuffer		- pointer to the sub-buffer page
 * @data		- pointer to the start of data on the sub-buffer page
 * @index		- index from @data to the @curr event data
 * @curr		- offset from @data to the start of current event
 *			   (includes metadata)
 * @next		- offset from @data to the start of next event
 * @size		- The size of data on @data
 * @start		- The offset from @subbuffer where @data lives
 *
 * @read_4		- Function to read 4 raw bytes (may swap)
 * @read_8		- Function to read 8 raw bytes (may swap)
 * @read_long		- Function to read a long word (4 or 8 bytes with needed swap)
 */
struct kbuffer {
	unsigned long long 	timestamp;
	long long		lost_events;
	unsigned long		flags;
	void			*subbuffer;
	void			*data;
	unsigned int		index;
	unsigned int		curr;
	unsigned int		next;
	unsigned int		size;
	unsigned int		start;

	unsigned int (*read_4)(void *ptr);
	unsigned long long (*read_8)(void *ptr);
	unsigned long long (*read_long)(struct kbuffer *kbuf, void *ptr);
	int (*next_event)(struct kbuffer *kbuf);
};

static void *zmalloc(size_t size)
{
	return calloc(1, size);
}

static int host_is_bigendian(void)
{
	unsigned char str[] = { 0x1, 0x2, 0x3, 0x4 };
	unsigned int *ptr;

	ptr = (unsigned int *)str;
	return *ptr == 0x01020304;
}

static int do_swap(struct kbuffer *kbuf)
{
	return ((kbuf->flags & KBUFFER_FL_HOST_BIG_ENDIAN) + kbuf->flags) &
		ENDIAN_MASK;
}

static unsigned long long __read_8(void *ptr)
{
	unsigned long long data = *(unsigned long long *)ptr;

	return data;
}

static unsigned long long __read_8_sw(void *ptr)
{
	unsigned long long data = *(unsigned long long *)ptr;
	unsigned long long swap;

	swap = ((data & 0xffULL) << 56) |
		((data & (0xffULL << 8)) << 40) |
		((data & (0xffULL << 16)) << 24) |
		((data & (0xffULL << 24)) << 8) |
		((data & (0xffULL << 32)) >> 8) |
		((data & (0xffULL << 40)) >> 24) |
		((data & (0xffULL << 48)) >> 40) |
		((data & (0xffULL << 56)) >> 56);

	return swap;
}

static unsigned int __read_4(void *ptr)
{
	unsigned int data = *(unsigned int *)ptr;

	return data;
}

static unsigned int __read_4_sw(void *ptr)
{
	unsigned int data = *(unsigned int *)ptr;
	unsigned int swap;

	swap = ((data & 0xffULL) << 24) |
		((data & (0xffULL << 8)) << 8) |
		((data & (0xffULL << 16)) >> 8) |
		((data & (0xffULL << 24)) >> 24);

	return swap;
}

static unsigned long long read_8(struct kbuffer *kbuf, void *ptr)
{
	return kbuf->read_8(ptr);
}

static unsigned int read_4(struct kbuffer *kbuf, void *ptr)
{
	return kbuf->read_4(ptr);
}

static unsigned long long __read_long_8(struct kbuffer *kbuf, void *ptr)
{
	return kbuf->read_8(ptr);
}

static unsigned long long __read_long_4(struct kbuffer *kbuf, void *ptr)
{
	return kbuf->read_4(ptr);
}

static unsigned long long read_long(struct kbuffer *kbuf, void *ptr)
{
	return kbuf->read_long(kbuf, ptr);
}

static int calc_index(struct kbuffer *kbuf, void *ptr)
{
	return (unsigned long)ptr - (unsigned long)kbuf->data;
}

static int __next_event(struct kbuffer *kbuf);

/**
 * kbuffer_alloc - allocat a new kbuffer
 * @size;	enum to denote size of word
 * @endian:	enum to denote endianness
 *
 * Allocates and returns a new kbuffer.
 */
struct kbuffer *
kbuffer_alloc(enum kbuffer_long_size size, enum kbuffer_endian endian)
{