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![Zou Wei](/assets/img/avatar_default.png)
Fixes coccicheck warning: tools/lib/traceevent/kbuffer-parse.c:441:2-3: Unneeded semicolon Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Zou Wei <zou_wei@huawei.com> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Link: http://lore.kernel.org/lkml/1588065121-71236-1-git-send-email-zou_wei@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
778 lines
18 KiB
C
778 lines
18 KiB
C
// SPDX-License-Identifier: LGPL-2.1
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/*
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* Copyright (C) 2009, 2010 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
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*
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "kbuffer.h"
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#define MISSING_EVENTS (1UL << 31)
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#define MISSING_STORED (1UL << 30)
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#define COMMIT_MASK ((1 << 27) - 1)
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enum {
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KBUFFER_FL_HOST_BIG_ENDIAN = (1<<0),
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KBUFFER_FL_BIG_ENDIAN = (1<<1),
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KBUFFER_FL_LONG_8 = (1<<2),
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KBUFFER_FL_OLD_FORMAT = (1<<3),
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};
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#define ENDIAN_MASK (KBUFFER_FL_HOST_BIG_ENDIAN | KBUFFER_FL_BIG_ENDIAN)
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/** kbuffer
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* @timestamp - timestamp of current event
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* @lost_events - # of lost events between this subbuffer and previous
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* @flags - special flags of the kbuffer
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* @subbuffer - pointer to the sub-buffer page
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* @data - pointer to the start of data on the sub-buffer page
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* @index - index from @data to the @curr event data
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* @curr - offset from @data to the start of current event
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* (includes metadata)
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* @next - offset from @data to the start of next event
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* @size - The size of data on @data
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* @start - The offset from @subbuffer where @data lives
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*
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* @read_4 - Function to read 4 raw bytes (may swap)
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* @read_8 - Function to read 8 raw bytes (may swap)
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* @read_long - Function to read a long word (4 or 8 bytes with needed swap)
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*/
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struct kbuffer {
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unsigned long long timestamp;
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long long lost_events;
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unsigned long flags;
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void *subbuffer;
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void *data;
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unsigned int index;
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unsigned int curr;
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unsigned int next;
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unsigned int size;
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unsigned int start;
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unsigned int (*read_4)(void *ptr);
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unsigned long long (*read_8)(void *ptr);
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unsigned long long (*read_long)(struct kbuffer *kbuf, void *ptr);
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int (*next_event)(struct kbuffer *kbuf);
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};
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static void *zmalloc(size_t size)
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{
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return calloc(1, size);
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}
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static int host_is_bigendian(void)
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{
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unsigned char str[] = { 0x1, 0x2, 0x3, 0x4 };
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unsigned int *ptr;
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ptr = (unsigned int *)str;
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return *ptr == 0x01020304;
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}
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static int do_swap(struct kbuffer *kbuf)
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{
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return ((kbuf->flags & KBUFFER_FL_HOST_BIG_ENDIAN) + kbuf->flags) &
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ENDIAN_MASK;
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}
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static unsigned long long __read_8(void *ptr)
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{
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unsigned long long data = *(unsigned long long *)ptr;
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return data;
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}
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static unsigned long long __read_8_sw(void *ptr)
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{
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unsigned long long data = *(unsigned long long *)ptr;
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unsigned long long swap;
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swap = ((data & 0xffULL) << 56) |
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((data & (0xffULL << 8)) << 40) |
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((data & (0xffULL << 16)) << 24) |
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((data & (0xffULL << 24)) << 8) |
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((data & (0xffULL << 32)) >> 8) |
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((data & (0xffULL << 40)) >> 24) |
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((data & (0xffULL << 48)) >> 40) |
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((data & (0xffULL << 56)) >> 56);
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return swap;
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}
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static unsigned int __read_4(void *ptr)
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{
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unsigned int data = *(unsigned int *)ptr;
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return data;
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}
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static unsigned int __read_4_sw(void *ptr)
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{
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unsigned int data = *(unsigned int *)ptr;
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unsigned int swap;
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swap = ((data & 0xffULL) << 24) |
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((data & (0xffULL << 8)) << 8) |
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((data & (0xffULL << 16)) >> 8) |
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((data & (0xffULL << 24)) >> 24);
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return swap;
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}
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static unsigned long long read_8(struct kbuffer *kbuf, void *ptr)
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{
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return kbuf->read_8(ptr);
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}
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static unsigned int read_4(struct kbuffer *kbuf, void *ptr)
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{
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return kbuf->read_4(ptr);
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}
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static unsigned long long __read_long_8(struct kbuffer *kbuf, void *ptr)
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{
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return kbuf->read_8(ptr);
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}
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static unsigned long long __read_long_4(struct kbuffer *kbuf, void *ptr)
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{
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return kbuf->read_4(ptr);
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}
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static unsigned long long read_long(struct kbuffer *kbuf, void *ptr)
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{
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return kbuf->read_long(kbuf, ptr);
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}
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static int calc_index(struct kbuffer *kbuf, void *ptr)
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{
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return (unsigned long)ptr - (unsigned long)kbuf->data;
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}
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static int __next_event(struct kbuffer *kbuf);
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/**
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* kbuffer_alloc - allocat a new kbuffer
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* @size; enum to denote size of word
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* @endian: enum to denote endianness
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*
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* Allocates and returns a new kbuffer.
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*/
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struct kbuffer *
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kbuffer_alloc(enum kbuffer_long_size size, enum kbuffer_endian endian)
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{
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struct kbuffer *kbuf;
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int flags = 0;
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switch (size) {
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case KBUFFER_LSIZE_4:
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break;
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case KBUFFER_LSIZE_8:
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flags |= KBUFFER_FL_LONG_8;
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break;
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default:
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return NULL;
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}
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switch (endian) {
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case KBUFFER_ENDIAN_LITTLE:
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break;
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case KBUFFER_ENDIAN_BIG:
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flags |= KBUFFER_FL_BIG_ENDIAN;
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break;
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default:
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return NULL;
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}
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kbuf = zmalloc(sizeof(*kbuf));
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if (!kbuf)
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return NULL;
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kbuf->flags = flags;
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if (host_is_bigendian())
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kbuf->flags |= KBUFFER_FL_HOST_BIG_ENDIAN;
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if (do_swap(kbuf)) {
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kbuf->read_8 = __read_8_sw;
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kbuf->read_4 = __read_4_sw;
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} else {
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kbuf->read_8 = __read_8;
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kbuf->read_4 = __read_4;
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}
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if (kbuf->flags & KBUFFER_FL_LONG_8)
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kbuf->read_long = __read_long_8;
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else
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kbuf->read_long = __read_long_4;
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/* May be changed by kbuffer_set_old_format() */
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kbuf->next_event = __next_event;
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return kbuf;
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}
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/** kbuffer_free - free an allocated kbuffer
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* @kbuf: The kbuffer to free
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*
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* Can take NULL as a parameter.
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*/
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void kbuffer_free(struct kbuffer *kbuf)
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{
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free(kbuf);
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}
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static unsigned int type4host(struct kbuffer *kbuf,
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unsigned int type_len_ts)
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{
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if (kbuf->flags & KBUFFER_FL_BIG_ENDIAN)
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return (type_len_ts >> 29) & 3;
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else
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return type_len_ts & 3;
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}
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static unsigned int len4host(struct kbuffer *kbuf,
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unsigned int type_len_ts)
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{
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if (kbuf->flags & KBUFFER_FL_BIG_ENDIAN)
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return (type_len_ts >> 27) & 7;
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else
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return (type_len_ts >> 2) & 7;
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}
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static unsigned int type_len4host(struct kbuffer *kbuf,
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unsigned int type_len_ts)
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{
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if (kbuf->flags & KBUFFER_FL_BIG_ENDIAN)
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return (type_len_ts >> 27) & ((1 << 5) - 1);
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else
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return type_len_ts & ((1 << 5) - 1);
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}
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static unsigned int ts4host(struct kbuffer *kbuf,
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unsigned int type_len_ts)
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{
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if (kbuf->flags & KBUFFER_FL_BIG_ENDIAN)
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return type_len_ts & ((1 << 27) - 1);
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else
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return type_len_ts >> 5;
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}
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/*
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* Linux 2.6.30 and earlier (not much ealier) had a different
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* ring buffer format. It should be obsolete, but we handle it anyway.
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*/
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enum old_ring_buffer_type {
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OLD_RINGBUF_TYPE_PADDING,
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OLD_RINGBUF_TYPE_TIME_EXTEND,
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OLD_RINGBUF_TYPE_TIME_STAMP,
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OLD_RINGBUF_TYPE_DATA,
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};
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static unsigned int old_update_pointers(struct kbuffer *kbuf)
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{
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unsigned long long extend;
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unsigned int type_len_ts;
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unsigned int type;
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unsigned int len;
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unsigned int delta;
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unsigned int length;
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void *ptr = kbuf->data + kbuf->curr;
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type_len_ts = read_4(kbuf, ptr);
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ptr += 4;
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type = type4host(kbuf, type_len_ts);
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len = len4host(kbuf, type_len_ts);
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delta = ts4host(kbuf, type_len_ts);
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switch (type) {
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case OLD_RINGBUF_TYPE_PADDING:
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kbuf->next = kbuf->size;
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return 0;
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case OLD_RINGBUF_TYPE_TIME_EXTEND:
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extend = read_4(kbuf, ptr);
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extend <<= TS_SHIFT;
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extend += delta;
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delta = extend;
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ptr += 4;
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length = 0;
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break;
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case OLD_RINGBUF_TYPE_TIME_STAMP:
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/* should never happen! */
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kbuf->curr = kbuf->size;
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kbuf->next = kbuf->size;
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kbuf->index = kbuf->size;
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return -1;
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default:
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if (len)
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length = len * 4;
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else {
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length = read_4(kbuf, ptr);
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length -= 4;
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ptr += 4;
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}
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break;
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}
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kbuf->timestamp += delta;
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kbuf->index = calc_index(kbuf, ptr);
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kbuf->next = kbuf->index + length;
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return type;
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}
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static int __old_next_event(struct kbuffer *kbuf)
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{
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int type;
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do {
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kbuf->curr = kbuf->next;
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if (kbuf->next >= kbuf->size)
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return -1;
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type = old_update_pointers(kbuf);
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} while (type == OLD_RINGBUF_TYPE_TIME_EXTEND || type == OLD_RINGBUF_TYPE_PADDING);
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return 0;
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}
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static unsigned int
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translate_data(struct kbuffer *kbuf, void *data, void **rptr,
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unsigned long long *delta, int *length)
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{
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unsigned long long extend;
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unsigned int type_len_ts;
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unsigned int type_len;
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type_len_ts = read_4(kbuf, data);
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data += 4;
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type_len = type_len4host(kbuf, type_len_ts);
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*delta = ts4host(kbuf, type_len_ts);
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switch (type_len) {
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case KBUFFER_TYPE_PADDING:
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*length = read_4(kbuf, data);
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break;
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case KBUFFER_TYPE_TIME_EXTEND:
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extend = read_4(kbuf, data);
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data += 4;
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extend <<= TS_SHIFT;
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extend += *delta;
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*delta = extend;
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*length = 0;
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break;
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case KBUFFER_TYPE_TIME_STAMP:
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data += 12;
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*length = 0;
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break;
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case 0:
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*length = read_4(kbuf, data) - 4;
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*length = (*length + 3) & ~3;
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data += 4;
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break;
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default:
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*length = type_len * 4;
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break;
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}
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*rptr = data;
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return type_len;
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}
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static unsigned int update_pointers(struct kbuffer *kbuf)
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{
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unsigned long long delta;
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unsigned int type_len;
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int length;
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void *ptr = kbuf->data + kbuf->curr;
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type_len = translate_data(kbuf, ptr, &ptr, &delta, &length);
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kbuf->timestamp += delta;
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kbuf->index = calc_index(kbuf, ptr);
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kbuf->next = kbuf->index + length;
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return type_len;
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}
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/**
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* kbuffer_translate_data - read raw data to get a record
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* @swap: Set to 1 if bytes in words need to be swapped when read
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* @data: The raw data to read
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* @size: Address to store the size of the event data.
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*
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* Returns a pointer to the event data. To determine the entire
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* record size (record metadata + data) just add the difference between
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* @data and the returned value to @size.
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*/
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void *kbuffer_translate_data(int swap, void *data, unsigned int *size)
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{
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unsigned long long delta;
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struct kbuffer kbuf;
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int type_len;
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int length;
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void *ptr;
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if (swap) {
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kbuf.read_8 = __read_8_sw;
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kbuf.read_4 = __read_4_sw;
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kbuf.flags = host_is_bigendian() ? 0 : KBUFFER_FL_BIG_ENDIAN;
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} else {
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kbuf.read_8 = __read_8;
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kbuf.read_4 = __read_4;
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kbuf.flags = host_is_bigendian() ? KBUFFER_FL_BIG_ENDIAN: 0;
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}
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type_len = translate_data(&kbuf, data, &ptr, &delta, &length);
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switch (type_len) {
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case KBUFFER_TYPE_PADDING:
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case KBUFFER_TYPE_TIME_EXTEND:
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case KBUFFER_TYPE_TIME_STAMP:
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return NULL;
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}
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*size = length;
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return ptr;
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}
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static int __next_event(struct kbuffer *kbuf)
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{
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int type;
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do {
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kbuf->curr = kbuf->next;
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if (kbuf->next >= kbuf->size)
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return -1;
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type = update_pointers(kbuf);
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} while (type == KBUFFER_TYPE_TIME_EXTEND || type == KBUFFER_TYPE_PADDING);
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return 0;
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}
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static int next_event(struct kbuffer *kbuf)
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{
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return kbuf->next_event(kbuf);
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}
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/**
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* kbuffer_next_event - increment the current pointer
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* @kbuf: The kbuffer to read
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* @ts: Address to store the next record's timestamp (may be NULL to ignore)
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*
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* Increments the pointers into the subbuffer of the kbuffer to point to the
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* next event so that the next kbuffer_read_event() will return a
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* new event.
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*
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* Returns the data of the next event if a new event exists on the subbuffer,
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* NULL otherwise.
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*/
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void *kbuffer_next_event(struct kbuffer *kbuf, unsigned long long *ts)
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{
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int ret;
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if (!kbuf || !kbuf->subbuffer)
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return NULL;
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ret = next_event(kbuf);
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if (ret < 0)
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return NULL;
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if (ts)
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*ts = kbuf->timestamp;
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return kbuf->data + kbuf->index;
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}
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/**
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* kbuffer_load_subbuffer - load a new subbuffer into the kbuffer
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* @kbuf: The kbuffer to load
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* @subbuffer: The subbuffer to load into @kbuf.
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*
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* Load a new subbuffer (page) into @kbuf. This will reset all
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* the pointers and update the @kbuf timestamp. The next read will
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* return the first event on @subbuffer.
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*
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* Returns 0 on succes, -1 otherwise.
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*/
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int kbuffer_load_subbuffer(struct kbuffer *kbuf, void *subbuffer)
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{
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unsigned long long flags;
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void *ptr = subbuffer;
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if (!kbuf || !subbuffer)
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return -1;
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kbuf->subbuffer = subbuffer;
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kbuf->timestamp = read_8(kbuf, ptr);
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ptr += 8;
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kbuf->curr = 0;
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if (kbuf->flags & KBUFFER_FL_LONG_8)
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kbuf->start = 16;
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else
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kbuf->start = 12;
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kbuf->data = subbuffer + kbuf->start;
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flags = read_long(kbuf, ptr);
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kbuf->size = (unsigned int)flags & COMMIT_MASK;
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if (flags & MISSING_EVENTS) {
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if (flags & MISSING_STORED) {
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ptr = kbuf->data + kbuf->size;
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kbuf->lost_events = read_long(kbuf, ptr);
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} else
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kbuf->lost_events = -1;
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} else
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kbuf->lost_events = 0;
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kbuf->index = 0;
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kbuf->next = 0;
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next_event(kbuf);
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return 0;
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}
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|
|
/**
|
|
* 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);
|
|
data = kbuffer_read_event(kbuf, ts);
|
|
|
|
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;
|
|
}
|
|
|
|
/**
|
|
* kbuffer_raw_get - get raw buffer info
|
|
* @kbuf: The kbuffer
|
|
* @subbuf: Start of mapped subbuffer
|
|
* @info: Info descriptor to fill in
|
|
*
|
|
* For debugging. This can return internals of the ring buffer.
|
|
* Expects to have info->next set to what it will read.
|
|
* The type, length and timestamp delta will be filled in, and
|
|
* @info->next will be updated to the next element.
|
|
* The @subbuf is used to know if the info is passed the end of
|
|
* data and NULL will be returned if it is.
|
|
*/
|
|
struct kbuffer_raw_info *
|
|
kbuffer_raw_get(struct kbuffer *kbuf, void *subbuf, struct kbuffer_raw_info *info)
|
|
{
|
|
unsigned long long flags;
|
|
unsigned long long delta;
|
|
unsigned int type_len;
|
|
unsigned int size;
|
|
int start;
|
|
int length;
|
|
void *ptr = info->next;
|
|
|
|
if (!kbuf || !subbuf)
|
|
return NULL;
|
|
|
|
if (kbuf->flags & KBUFFER_FL_LONG_8)
|
|
start = 16;
|
|
else
|
|
start = 12;
|
|
|
|
flags = read_long(kbuf, subbuf + 8);
|
|
size = (unsigned int)flags & COMMIT_MASK;
|
|
|
|
if (ptr < subbuf || ptr >= subbuf + start + size)
|
|
return NULL;
|
|
|
|
type_len = translate_data(kbuf, ptr, &ptr, &delta, &length);
|
|
|
|
info->next = ptr + length;
|
|
|
|
info->type = type_len;
|
|
info->delta = delta;
|
|
info->length = length;
|
|
|
|
return info;
|
|
}
|