- 根目录:
- tools
- lib
- traceevent
- kbuffer-parse.c
/*
* Copyright (C) 2009, 2010 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License (not later!)
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "kbuffer.h"
#define MISSING_EVENTS (1 << 31)
#define MISSING_STORED (1 << 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)
{
struct kbuffer *kbuf;
int flags = 0;
switch (size) {
case KBUFFER_LSIZE_4:
break;
case KBUFFER_LSIZE_8:
flags |= KBUFFER_FL_LONG_8;
break;
default:
return NULL;
}
switch (endian) {
case KBUFFER_ENDIAN_LITTLE:
break;
case KBUFFER_ENDIAN_BIG:
flags |= KBUFFER_FL_BIG_ENDIAN;
break;
default:
return NULL;
}
kbuf = zmalloc(sizeof(*kbuf));
if (!kbuf)
return NULL;
kbuf->flags = flags;
if (host_is_bigendian())
kbuf->flags |= KBUFFER_FL_HOST_BIG_ENDIAN;
if (do_swap(kbuf)) {
kbuf->read_8 = __read_8_sw;
kbuf->read_4 = __read_4_sw;
} else {
kbuf->read_8 = __read_8;
kbuf->read_4 = __read_4;
}
if (kbuf->flags & KBUFFER_FL_LONG_8)
kbuf->read_long = __read_long_8;
else
kbuf->read_long = __read_long_4;
/* May be changed by kbuffer_set_old_format() */
kbuf->next_event = __next_event;
return kbuf;
}
/** kbuffer_free - free an allocated kbuffer
* @kbuf: The kbuffer to free
*
* Can take NULL as a parameter.
*/
void kbuffer_free(struct kbuffer *kbuf)
{
free(kbuf);
}
static unsigned int type4host(struct kbuffer *kbuf,
unsigned int type_len_ts)
{
if (kbuf->flags & KBUFFER_FL_BIG_ENDIAN)
return (type_len_ts >> 29) & 3;
else
return type_len_ts & 3;
}
static unsigned int len4host(struct kbuffer *kbuf,
unsigned int type_len_ts)
{
if (kbuf->flags & KBUFFER_FL_BIG_ENDIAN)
return (type_len_ts >> 27) & 7;
else
return (type_len_ts >> 2) & 7;
}
static unsigned int type_len4host(struct kbuffer *kbuf,
unsigned int type_len_ts)
{
if (kbuf->flags & KBUFFER_FL_BIG_ENDIAN)
return (type_len_ts >> 27) & ((1 << 5) - 1);
else
return type_len_ts & ((1 << 5) - 1);
}
static unsigned int ts4host(struct kbuffer *kbuf,
unsigned int type_len_ts)
{
if (kbuf->flags & KBUFFER_FL_BIG_ENDIAN)
return type_len_ts & ((1 << 27) - 1);
else
return type_len_ts >> 5;
}
/*
* Linux 2.6.30 and earlier (not much ealier) had a different
* ring buffer format. It should be obsolete, but we handle it anyway.
*/
enum old_ring_buffer_type {
OLD_RINGBUF_TYPE_PADDING,
OLD_RINGBUF_TYPE_TIME_EXTEND,
OLD_RINGBUF_TYPE_TIME_STAMP,
OLD_RINGBUF_TYPE_DATA,
};
static unsigned int old_update_pointers(struct kbuffer *kbuf)
{
unsigned long long extend;
unsigned int type_len_ts;
unsigned int type;
unsigned int len;
unsigned int delta;
unsigned int length;
void *ptr = kbuf->data + kbuf->curr;
type_len_ts = read_4(kbuf, ptr);
ptr += 4;
type = type4host(kbuf, type_len_ts);
len = len4host(kbuf, type_len_ts);
delta = ts4host(kbuf, type_len_ts);
switch (type) {
case OLD_RINGBUF_TYPE_PADDING:
kbuf->next = kbuf->size;
return 0;
case OLD_RINGBUF_TYPE_TIME_EXTEND:
extend = read_4(kbuf, ptr);
extend <<= TS_SHIFT;
extend += delta;
delta = extend;
ptr += 4;
break;
case OLD_RINGBUF_TYPE_TIME_STAMP:
/* should never happen! */
kbuf->curr = kbuf->size;
kbuf->next = kbuf->size;
kbuf->index = kbuf->size;
return -1;
default:
if (len)
length = len * 4;
else {
length = read_4(kbuf, ptr);
length -= 4;
ptr += 4;
}
break;
}
kbuf->timestamp += delta;
kbuf->index = calc_index(kbuf, ptr);
kbuf->next = kbuf->index + length;
return type;
}
static int __old_next_event(struct kbuffer *kbuf)
{
int type;
do {
kbuf->curr = kbuf->next;
if (kbuf->next >= kbuf->size)
return -1;
type = old_update_pointers(kbuf);
} while (type == OLD_RINGBUF_TYPE_TIME_EXTEND || type == OLD_RINGBUF_TYPE_PADDING);
return 0;
}
static unsigned int
translate_data(struct kbuffer *kbuf, void *data, void **rptr,
unsigned long long *delta, int *length)
{
unsigned long long extend;
unsigned int type_len_ts;
unsigned int type_len;
type_len_ts = read_4(kbuf, data);
data += 4;
type_len = type_len4host(kbuf, type_len_ts);
*delta = ts4host(kbuf, type_len_ts);
switch (type_len) {
case KBUFFER_TYPE_PADDING:
*length = read_4(kbuf, data);
break;
case KBUFFER_TYPE_TIME_EXTEND:
extend = read_4(kbuf, data);
data += 4;
extend <<= TS_SHIFT;
extend += *delta;
*delta = extend;
*length = 0;
break;
case KBUFFER_TYPE_TIME_STAMP:
data += 12;
*length = 0;
break;
case 0:
*length = read_4(kbuf, data) - 4;
*length = (*length + 3) & ~3;
data += 4;
break;
default:
*length = type_len * 4;
break;
}
*rptr = data;
return type_len;
}
static unsigned int update_pointers(struct kbuffer *kbuf)
{
unsigned long long delta;
unsigned int type_len;
int length;
void *ptr = kbuf->data + kbuf->curr;
type_len = translate_data(kbuf, ptr, &ptr, &delta, &length);
kbuf->timestamp += delta;
kbuf->index = calc_index(kbuf, ptr);
kbuf->next = kbuf->index + length;
return type_len;
}
/**
* kbuffer_translate_data - read raw data to get a record
* @swap: Set to 1 if bytes in words need to be swapped when read
* @data: The raw data to read
* @size: Address to store the size of the event data.
*
* Returns a pointer to the event data. To determine the entire
* record size (record metadata + data) just add the difference between
* @data and the returned value to @size.
*/
void *kbuffer_translate_data(int swap, void *data, unsigned int *size)
{
unsigned long long delta;
struct kbuffer kbuf;
int type_len;
int length;
void *ptr;
if (swap) {
kbuf.read_8 = __read_8_sw;
kbuf.read_4 = __read_4_sw;
kbuf.flags = host_is_bigendian() ? 0 : KBUFFER_FL_BIG_ENDIAN;
} else {
kbuf.read_8 = __read_8;
kbuf.read_4 = __read_4;
kbuf.flags = host_is_bigendian() ? KBUFFER_FL_BIG_ENDIAN: 0;
}
type_len = translate_data(&kbuf, data, &ptr, &delta, &length);
switch (type_len) {
case KBUFFER_TYPE_PADDING:
case KBUFFER_TYPE_TIME_EXTEND:
case KBUFFER_TYPE_TIME_STAMP:
return NULL;
};
*size = length;
return ptr;
}
static int __next_event(struct kbuffer *kbuf)
{
int type;
do {
kbuf->curr = kbuf->next;
if (kbuf->next >= kbuf->size)
return -1;
type = update_pointers(kbuf);
} while (type == KBUFFER_TYPE_TIME_EXTEND || type == KBUFFER_TYPE_PADDING);
return 0;
}
static int next_event(struct kbuffer *kbuf)
{
return kbuf->next_event(kbuf);
}
/**
* kbuffer_next_event - increment the current pointer
* @kbuf: The kbuffer to read
* @ts: Address to store the next record's timestamp (may be NULL to ignore)
*
* Increments the pointers into the subbuffer of the kbuffer to point to the
* next event so that the next kbuffer_read_event() will return a
* new event.
*
* Returns the data of the next event if a new event exists on the subbuffer,
* NULL otherwise.
*/
void *kbuffer_next_event(struct kbuffer *kbuf, unsigned long long *ts)
{
int ret;
if (!kbuf || !kbuf->subbuffer)
return NULL;
ret = next_event(kbuf);
if (ret < 0)
return NULL;
if (ts)
*ts = kbuf->timestamp;
return kbuf->data + kbuf->index;
}
/**
* kbuffer_load_subbuffer - load a new subbuffer into the kbuffer
* @kbuf: The kbuffer to load
* @subbuffer: The subbuffer to load into @kbuf.
*
* Load a new subbuffer (page) into @kbuf. This will reset all
* the pointers and update the @kbuf timestamp. The next read will
* return the first event on @subbuffer.
*
* Returns 0 on succes, -1 otherwise.
*/
int kbuffer_load_subbuffer(struct kbuffer *kbuf, void *subbuffer)
{
unsigned long long flags;
void *ptr = subbuffer;
if (!kbuf || !subbuffer)
return -1;
kbuf->subbuffer = subbuffer;
kbuf->timestamp = read_8(kbuf, ptr);
ptr += 8;
kbuf->curr = 0;
if (kbuf->flags & KBUFFER_FL_LONG_8)
kbuf->start = 16;
else
kbuf->start = 12;
kbuf->data = subbuffer + kbuf->start;
flags = read_long(kbuf, ptr);
kbuf->size = (unsigned int)flags & COMMIT_MASK;
if (flags & MISSING_EVENTS) {
if (flags & MISSING_STORED) {
ptr = kbuf->data + kbuf->size;
kbuf->lost_events = read_long(kbuf, ptr);
} else
kbuf->lost_events = -1;
} else
kbuf->lost_events = 0;
kbuf->index = 0;
kbuf->next = 0;
next_event(kbuf);
return 0;
}
/**
* kbuffer_read_event - read the next event in the kbuffer subbuffer
* @kbuf: The kbuffer to read from
* @ts: The address to store the timestamp of the event (may be NULL to ignore)
*
* Returns a pointer to the data part of the current event.
* NULL if no event is left on the subbuffer.
*/
void *kbuffer_read_event(struct kbuffer *kbuf, unsigned long long *ts)
{
if (!kbuf || !kbuf->subbuffer)
return NULL;
if (kbuf->curr >= kbuf->size)
return NULL;
if (ts)
*ts = kbuf->timestamp;
return kbuf->data + kbuf->index;
}
/**
* kbuffer_timestamp - Return the timestamp of the current event
* @kbuf: The kbuffer to read from
*
* Returns the timestamp of the current (next) event.
*/
unsigned long long kbuffer_timestamp(struct kbuffer *kbuf)
{
return kbuf->timestamp;
}
/**
* kbuffer_read_at_offset - read the event that is at offset
* @kbuf: The kbuffer to read from
* @offset: The offset into the subbuffer
* @ts: The address to store the timestamp of the event (may be NULL to ignore)
*
* The @offset must be an index from the @kbuf subbuffer beginning.
* If @offset is bigger than the stored subbuffer, NULL will be returned.
*
* Returns the data of the record that is at @offset. Note, @offset does
* not need to be the start of the record, the offset just needs to be
* in the record (or beginning of it).
*
* Note, the kbuf timestamp and pointers are updated to the
* returned record. That is, kbuffer_read_event() will return the same
* data and timestamp, and kbuffer_next_event() will increment from
* this record.
*/
void *kbuffer_read_at_offset(struct kbuffer *kbuf, int offset,
unsigned long long *ts)
{
void *data;
if (offset < kbuf->start)
offset = 0;
else
offset -= kbuf->start;
/* Reset the buffer */
kbuffer_load_subbuffer(kbuf, kbuf->subbuffer);
while (kbuf->curr < offset) {
data = kbuffer_next_event(kbuf, ts);
if (!data)
break;
}
return data;
}
/**
* kbuffer_subbuffer_size - the size of the loaded subbuffer
* @kbuf: The kbuffer to read from
*
* Returns the size of the subbuffer. Note, this size is
* where the last event resides. The stored subbuffer may actually be
* bigger due to padding and such.
*/
int kbuffer_subbuffer_size(struct kbuffer *kbuf)
{
return kbuf->size;
}
/**
* kbuffer_curr_index - Return the index of the record
* @kbuf: The kbuffer to read from
*
* Returns the index from the start of the data part of
* the subbuffer to the current location. Note this is not
* from the start of the subbuffer. An index of zero will
* point to the first record. Use kbuffer_curr_offset() for
* the actually offset (that can be used by kbuffer_read_at_offset())
*/
int kbuffer_curr_index(struct kbuffer *kbuf)
{
return kbuf->curr;
}
/**
* kbuffer_curr_offset - Return the offset of the record
* @kbuf: The kbuffer to read from
*
* Returns the offset from the start of the subbuffer to the
* current location.
*/
int kbuffer_curr_offset(struct kbuffer *kbuf)
{
return kbuf->curr + kbuf->start;
}
/**
* kbuffer_event_size - return the size of the event data
* @kbuf: The kbuffer to read
*
* Returns the size of the event data (the payload not counting
* the meta data of the record) of the current event.
*/
int kbuffer_event_size(struct kbuffer *kbuf)
{
return kbuf->next - kbuf->index;
}
/**
* kbuffer_curr_size - return the size of the entire record
* @kbuf: The kbuffer to read
*
* Returns the size of the entire record (meta data and payload)
* of the current event.
*/
int kbuffer_curr_size(struct kbuffer *kbuf)
{
return kbuf->next - kbuf->curr;
}
/**
* kbuffer_missed_events - return the # of missed events from last event.
* @kbuf: The kbuffer to read from
*
* Returns the # of missed events (if recorded) before the current
* event. Note, only events on the beginning of a subbuffer can
* have missed events, all other events within the buffer will be
* zero.
*/
int kbuffer_missed_events(struct kbuffer *kbuf)
{
/* Only the first event can have missed events */
if (kbuf->curr)
return 0;
return kbuf->lost_events;
}
/**
* kbuffer_set_old_forma - set the kbuffer to use the old format parsing
* @kbuf: The kbuffer to set
*
* This is obsolete (or should be). The first kernels to use the
* new ring buffer had a slightly different ring buffer format
* (2.6.30 and earlier). It is still somewhat supported by kbuffer,
* but should not be counted on in the future.
*/
void kbuffer_set_old_format(struct kbuffer *kbuf)
{
kbuf->flags |= KBUFFER_FL_OLD_FORMAT;
kbuf->next_event = __old_next_event;
}
/**
* kbuffer_start_of_data - return offset of where data starts on subbuffer
* @kbuf: The kbuffer
*
* Returns the location on the subbuffer where the data starts.
*/
int kbuffer_start_of_data(struct kbuffer *kbuf)
{
return kbuf->start;
}