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-rw-r--r--libibex/block.c595
1 files changed, 0 insertions, 595 deletions
diff --git a/libibex/block.c b/libibex/block.c
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--- a/libibex/block.c
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-/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*-
- *
- * Copyright (C) 2000 Helix Code, Inc.
- *
- * Authors: Michael Zucchi <notzed@helixcode.com>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Library General Public License
- * as published by the Free Software Foundation; either version 2 of
- * the License, or (at your option) any later version.
- *
- * This library 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
- * Library General Public License for more details.
- *
- * You should have received a copy of the GNU Library General Public
- * License along with the Gnome Library; see the file COPYING.LIB. If not,
- * write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- * Boston, MA 02111-1307, USA.
- */
-
-/*
- block file/cache/utility functions
-*/
-
-#include <stdio.h>
-
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <fcntl.h>
-#include <unistd.h>
-#include <errno.h>
-#include <string.h>
-#include <glib.h>
-
-#include "block.h"
-
-/*#define MALLOC_CHECK*/
-
-#ifdef MALLOC_CHECK
-#include <mcheck.h>
-#endif
-
-#define d(x)
-/*#define DEBUG*/
-
-int block_log;
-
-#ifdef IBEX_STATS
-static void
-init_stats(struct _memcache *index)
-{
- index->stats = g_hash_table_new(g_direct_hash, g_direct_equal);
-}
-
-static void
-dump_1_stat(int id, struct _stat_info *info, struct _memcache *index)
-{
- printf("%d %d %d %d %d\n", id, info->read, info->write, info->cache_hit, info->cache_miss);
-}
-
-static void
-dump_stats(struct _memcache *index)
-{
- printf("Block reads writes hits misses\n");
- g_hash_table_foreach(index->stats, dump_1_stat, index);
-}
-
-static void
-add_read(struct _memcache *index, int id)
-{
- struct _stat_info *info;
-
- info = g_hash_table_lookup(index->stats, (void *)id);
- if (info == NULL) {
- info = g_malloc0(sizeof(*info));
- g_hash_table_insert(index->stats, (void *)id, info);
- }
- info->read++;
-}
-
-static void
-add_write(struct _memcache *index, int id)
-{
- struct _stat_info *info;
-
- info = g_hash_table_lookup(index->stats, (void *)id);
- if (info == NULL) {
- info = g_malloc0(sizeof(*info));
- g_hash_table_insert(index->stats, (void *)id, info);
- }
- info->write++;
-}
-
-static void
-add_hit(struct _memcache *index, int id)
-{
- struct _stat_info *info;
-
- info = g_hash_table_lookup(index->stats, (void *)id);
- if (info == NULL) {
- info = g_malloc0(sizeof(*info));
- g_hash_table_insert(index->stats, (void *)id, info);
- }
- info->cache_hit++;
-}
-
-static void
-add_miss(struct _memcache *index, int id)
-{
- struct _stat_info *info;
-
- info = g_hash_table_lookup(index->stats, (void *)id);
- if (info == NULL) {
- info = g_malloc0(sizeof(*info));
- g_hash_table_insert(index->stats, (void *)id, info);
- }
- info->cache_miss++;
-}
-#endif /* IBEX_STATS */
-
-#ifdef MALLOC_CHECK
-static void
-checkmem(void *p)
-{
- if (p) {
- int status = mprobe(p);
-
- switch (status) {
- case MCHECK_HEAD:
- printf("Memory underrun at %p\n", p);
- abort();
- case MCHECK_TAIL:
- printf("Memory overrun at %p\n", p);
- abort();
- case MCHECK_FREE:
- printf("Double free %p\n", p);
- abort();
- }
- }
-}
-#endif
-
-/* simple list routines (for simplified memory management of cache/lists) */
-
-/**
- * ibex_list_new:
- * @v:
- *
- * Initialise a list header. A list header must always be initialised
- * before use.
- **/
-void ibex_list_new(struct _list *v)
-{
- v->head = (struct _listnode *)&v->tail;
- v->tail = 0;
- v->tailpred = (struct _listnode *)&v->head;
-}
-
-/**
- * ibex_list_addhead:
- * @l: List.
- * @n: Node to append.
- *
- * Prepend a listnode to the head of the list @l.
- *
- * Return value: Always @n.
- **/
-struct _listnode *ibex_list_addhead(struct _list *l, struct _listnode *n)
-{
- n->next = l->head;
- n->prev = (struct _listnode *)&l->head;
- l->head->prev = n;
- l->head = n;
- return n;
-}
-
-/**
- * ibex_list_addtail:
- * @l:
- * @n:
- *
- * Append a listnode to the end of the list @l.
- *
- * Return value: Always the same as @n.
- **/
-struct _listnode *ibex_list_addtail(struct _list *l, struct _listnode *n)
-{
- n->next = (struct _listnode *)&l->tail;
- n->prev = l->tailpred;
- l->tailpred->next = n;
- l->tailpred = n;
- return n;
-}
-
-/**
- * ibex_list_remove:
- * @n: The node to remove.
- *
- * Remove a listnode from a list.
- *
- * Return value: Always the same as @n.
- **/
-struct _listnode *ibex_list_remove(struct _listnode *n)
-{
- n->next->prev = n->prev;
- n->prev->next = n->next;
- return n;
-}
-
-static struct _memblock *
-memblock_addr(struct _block *block)
-{
- return (struct _memblock *)(((char *)block) - G_STRUCT_OFFSET(struct _memblock, data));
-}
-
-/* read/sync the rootblock into the block_cache structure */
-static int
-ibex_block_read_root(struct _memcache *block_cache)
-{
- lseek(block_cache->fd, 0, SEEK_SET);
- if (read(block_cache->fd, &block_cache->root, sizeof(block_cache->root)) != sizeof(block_cache->root)) {
-
- return -1;
- }
- return 0;
-}
-
-static int
-ibex_block_sync_root(struct _memcache *block_cache)
-{
- lseek(block_cache->fd, 0, SEEK_SET);
- if (write(block_cache->fd, &block_cache->root, sizeof(block_cache->root)) != sizeof(block_cache->root)) {
- return -1;
- }
- return fsync(block_cache->fd);
-}
-
-
-/**
- * ibex_block_dirty:
- * @block:
- *
- * Dirty a block. This will cause it to be written to disk on
- * a cache sync, or when the block is flushed from the cache.
- **/
-void
-ibex_block_dirty(struct _block *block)
-{
- memblock_addr(block)->flags |= BLOCK_DIRTY;
-}
-
-static void
-sync_block(struct _memcache *block_cache, struct _memblock *memblock)
-{
- if (block_log)
- printf("writing block %d\n", memblock->block);
-
- lseek(block_cache->fd, memblock->block, SEEK_SET);
- if (write(block_cache->fd, &memblock->data, sizeof(memblock->data)) != -1) {
- memblock->flags &= ~BLOCK_DIRTY;
- }
-#ifdef IBEX_STATS
- add_write(block_cache, memblock->block);
-#endif
-}
-
-/**
- * ibex_block_cache_sync:
- * @block_cache:
- *
- * Ensure the block cache is fully synced to disk.
- **/
-void
-ibex_block_cache_sync(struct _memcache *block_cache)
-{
- struct _memblock *memblock;
-
- memblock = (struct _memblock *)block_cache->nodes.head;
- while (memblock->next) {
-#ifdef MALLOC_CHECK
- checkmem(memblock);
-#endif
- if (memblock->flags & BLOCK_DIRTY) {
- sync_block(block_cache, memblock);
- }
- memblock = memblock->next;
- }
-
- block_cache->root.flags |= IBEX_ROOT_SYNCF;
- if (ibex_block_sync_root(block_cache) != 0) {
- block_cache->root.flags &= ~IBEX_ROOT_SYNCF;
- }
-
-#ifdef IBEX_STATS
- dump_stats(block_cache);
-#endif
-
-}
-
-#ifdef MALLOC_CHECK
-static void
-check_cache(struct _memcache *block_cache)
-{
- struct _memblock *mw, *mn;
-
- checkmem(block_cache);
- checkmem(block_cache->index);
-
- mw = (struct _memblock *)block_cache->nodes.head;
- mn = mw->next;
- while (mn) {
- checkmem(mw);
- mw = mn;
- mn = mn->next;
- }
-}
-#endif
-
-/**
- * ibex_block_cache_flush:
- * @block_cache:
- *
- * Ensure the block cache is fully synced to disk, and then flush
- * its contents from memory.
- **/
-void
-ibex_block_cache_flush(struct _memcache *block_cache)
-{
- struct _memblock *mw, *mn;
-
- ibex_block_cache_sync(block_cache);
-
- mw = (struct _memblock *)block_cache->nodes.head;
- mn = mw->next;
- while (mn) {
- g_hash_table_remove(block_cache->index, (void *)mw->block);
- g_free(mw);
- mw = mn;
- mn = mn->next;
- }
- ibex_list_new(&block_cache->nodes);
-}
-
-/**
- * ibex_block_read:
- * @block_cache:
- * @blockid:
- *
- * Read the data of a block by blockid. The data contents is backed by
- * the block cache, and should be considered static.
- *
- * TODO; should this return a NULL block on error?
- *
- * Return value: The address of the block data (which may be cached).
- **/
-struct _block *
-ibex_block_read(struct _memcache *block_cache, blockid_t blockid)
-{
- struct _memblock *memblock;
-
-#ifdef MALLOC_CHECK
- check_cache(block_cache);
-#endif
-
- /* nothing can read the root block directly */
- g_assert(blockid != 0);
- g_assert(blockid < block_cache->root.roof);
-
- memblock = g_hash_table_lookup(block_cache->index, (void *)blockid);
-
-#ifdef MALLOC_CHECK
- check_cache(block_cache);
-#endif
-
- if (memblock) {
- d(printf("foudn blockid in cache %d = %p\n", blockid, &memblock->data));
-
- /* 'access' page */
- ibex_list_remove((struct _listnode *)memblock);
- ibex_list_addtail(&block_cache->nodes, (struct _listnode *)memblock);
-
-#ifdef MALLOC_CHECK
- check_cache(block_cache);
-#endif
-
-#ifdef IBEX_STATS
- add_hit(block_cache, memblock->block);
-#endif
-
-#ifdef MALLOC_CHECK
- check_cache(block_cache);
-#endif
-
- return &memblock->data;
- }
-#ifdef IBEX_STATS
- add_miss(block_cache, blockid);
- add_read(block_cache, blockid);
-#endif
- if (block_log)
- printf("miss block %d\n", blockid);
-
- d(printf("loading blockid from disk %d\n", blockid));
- memblock = g_malloc(sizeof(*memblock));
- memblock->block = blockid;
- memblock->flags = 0;
- lseek(block_cache->fd, blockid, SEEK_SET);
- memset(&memblock->data, 0, sizeof(memblock->data));
- read(block_cache->fd, &memblock->data, sizeof(memblock->data));
-
- ibex_list_addtail(&block_cache->nodes, (struct _listnode *)memblock);
- g_hash_table_insert(block_cache->index, (void *)blockid, memblock);
- if (block_cache->count >= CACHE_SIZE) {
- struct _memblock *old = (struct _memblock *)block_cache->nodes.head;
- d(printf("discaring cache block %d\n", old->block));
- g_hash_table_remove(block_cache->index, (void *)old->block);
- ibex_list_remove((struct _listnode *)old);
- if (old->flags & BLOCK_DIRTY) {
- /* are we about to un-sync the file? update root and sync it */
- if (block_cache->root.flags & IBEX_ROOT_SYNCF) {
- printf("Unsyncing root block\n");
-
- block_cache->root.flags &= ~IBEX_ROOT_SYNCF;
- if (ibex_block_sync_root(block_cache) != 0) {
- /* what do we do? i dont know! */
- g_warning("Could not sync root block of index: %s", strerror(errno));
- }
- }
- sync_block(block_cache, old);
- }
- g_free(old);
- } else {
- block_cache->count++;
- }
-
- d(printf(" --- cached blocks : %d\n", block_cache->count));
-
-#ifdef MALLOC_CHECK
- check_cache(block_cache);
-#endif
- return &memblock->data;
-}
-
-/**
- * ibex_block_cache_open:
- * @name:
- * @flags: Flags as to open(2), should use O_RDWR and optionally O_CREAT.
- * @mode: Mose as to open(2)
- *
- * Open a block file.
- *
- * FIXME; this currently also initialises the word and name indexes
- * because their pointers are stored in the root block. Should be
- * upto the caller to manage these pointers/data.
- *
- * Return value: NULL if the backing file could not be opened.
- **/
-struct _memcache *
-ibex_block_cache_open(const char *name, int flags, int mode)
-{
- struct _memcache *block_cache = g_malloc0(sizeof(*block_cache));
-
- d(printf("opening ibex file: %s", name));
-
- /* setup cache */
- ibex_list_new(&block_cache->nodes);
- block_cache->count = 0;
- block_cache->index = g_hash_table_new(g_direct_hash, g_direct_equal);
- block_cache->fd = open(name, flags, mode);
-
- if (block_cache->fd == -1) {
- g_hash_table_destroy(block_cache->index);
- g_free(block_cache);
- return NULL;
- }
-
- ibex_block_read_root(block_cache);
- if (block_cache->root.roof == 0
- || memcmp(block_cache->root.version, IBEX_VERSION, 4)
- || ((block_cache->root.flags & IBEX_ROOT_SYNCF) == 0)) {
- (printf("Initialising superblock\n"));
- /* reset root data */
- memcpy(block_cache->root.version, IBEX_VERSION, 4);
- block_cache->root.roof = 1024;
- block_cache->root.free = 0;
- block_cache->root.words = 0;
- block_cache->root.names = 0;
- block_cache->root.tail = 0; /* list of tail blocks */
- block_cache->root.flags = 0;
- ibex_block_sync_root(block_cache);
- /* reset the file contents */
- ftruncate(block_cache->fd, 1024);
- } else {
- (printf("superblock already initialised:\n"
- " roof = %d\n free = %d\n words = %d\n names = %d\n tail = %d\n",
- block_cache->root.roof, block_cache->root.free,
- block_cache->root.words, block_cache->root.names, block_cache->root.tail));
- }
- /* FIXME: this should be moved higher up in the object tree */
- {
- struct _IBEXWord *ibex_create_word_index_mem(struct _memcache *bc, blockid_t *wordroot, blockid_t *nameroot);
-
- block_cache->words = ibex_create_word_index_mem(block_cache, &block_cache->root.words,&block_cache->root.names);
- }
-
-#ifdef IBEX_STATS
- init_stats(block_cache);
-#endif
-
- return block_cache;
-}
-
-/**
- * ibex_block_cache_close:
- * @block_cache:
- *
- * Close the block file, sync any remaining cached data
- * to disk, and free all resources.
- **/
-void
-ibex_block_cache_close(struct _memcache *block_cache)
-{
- struct _memblock *mw, *mn;
-
- ibex_block_cache_sync(block_cache);
- close(block_cache->fd);
-
- mw = (struct _memblock *)block_cache->nodes.head;
- mn = mw->next;
- while (mn) {
- g_free(mw);
- mw = mn;
- mn = mw->next;
- }
-
- g_hash_table_destroy(block_cache->index);
-
- g_free(block_cache);
-}
-
-/**
- * ibex_block_free:
- * @block_cache:
- * @blockid:
- *
- * Return a block to the free pool.
- **/
-void
-ibex_block_free(struct _memcache *block_cache, blockid_t blockid)
-{
- struct _block *block = ibex_block_read(block_cache, blockid);
-
- block->next = block_number(block_cache->root.free);
- block_cache->root.free = blockid;
- ibex_block_dirty((struct _block *)block);
-}
-
-/**
- * ibex_block_get:
- * @block_cache:
- *
- * Allocate a new block, or access a previously freed block and return
- * its block id. The block will have zeroed contents.
- *
- * Return value: 0 if there are no blocks left (disk full/read only
- * file, etc).
- **/
-blockid_t
-ibex_block_get(struct _memcache *block_cache)
-{
- struct _block *block;
- blockid_t head;
-
- if (block_cache->root.free) {
- head = block_cache->root.free;
- block = ibex_block_read(block_cache, head);
- block_cache->root.free = block_location(block->next);
- } else {
- /* TODO: check the block will fit first */
- /* TODO: no need to read this block, can allocate it manually (saves a syscall/read) */
- head = block_cache->root.roof;
- block_cache->root.roof += BLOCK_SIZE;
- block = ibex_block_read(block_cache, head);
- }
-
- g_assert(head != 0);
-
- d(printf("new block = %d\n", head));
- block->next = 0;
- block->used = 0;
- ibex_block_dirty(block);
- return head;
-}
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