forked from osmocom/wireshark
243 lines
6.7 KiB
C
243 lines
6.7 KiB
C
/* wmem_allocator_strict.c
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* Wireshark Memory Manager Strict Allocator
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* Copyright 2012, Evan Huus <eapache@gmail.com>
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "config.h"
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#include <string.h>
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#include <glib.h>
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#include "wmem_core.h"
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#include "wmem_allocator.h"
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#include "wmem_allocator_strict.h"
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/* In this allocator, we do everything we can to catch invalid memory accesses.
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* This includes using canaries (what Valgrind calls redzones) and
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* filling allocated and freed memory with garbage. Valgrind is still the
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* better tool on the platforms where it is available - use it instead if
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* possible.
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*/
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#define WMEM_CANARY_SIZE 8 /* in bytes */
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#define WMEM_CANARY_VALUE 0x9E
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#define WMEM_PREFILL 0xA1
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#define WMEM_POSTFILL 0x1A
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typedef struct _wmem_strict_allocator_block_t {
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struct _wmem_strict_allocator_block_t *prev, *next;
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/* Just the length of real_data, not counting the canaries */
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gsize data_len;
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} wmem_strict_allocator_block_t;
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#define WMEM_DATA_TO_BLOCK(DATA) ((wmem_strict_allocator_block_t*)((guint8*)(DATA) - WMEM_CANARY_SIZE - sizeof(wmem_strict_allocator_block_t)))
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#define WMEM_BLOCK_TO_DATA(BLOCK) ((void*)((guint8*)(BLOCK) + WMEM_CANARY_SIZE + sizeof(wmem_strict_allocator_block_t)))
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#define WMEM_BLOCK_TO_PRE_CANARY(BLOCK) ((guint8*)(BLOCK) + sizeof(wmem_strict_allocator_block_t))
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#define WMEM_BLOCK_TO_POST_CANARY(BLOCK) ((guint8*)(BLOCK) + WMEM_CANARY_SIZE + sizeof(wmem_strict_allocator_block_t) + (BLOCK)->data_len)
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#define WMEM_FULL_SIZE(SIZE) ((SIZE) + sizeof(wmem_strict_allocator_block_t) + (2*WMEM_CANARY_SIZE))
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typedef struct _wmem_strict_allocator_t {
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wmem_strict_allocator_block_t *blocks;
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} wmem_strict_allocator_t;
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/*
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* some internal helper functions
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*/
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static inline void
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wmem_strict_block_check_canaries(wmem_strict_allocator_block_t *block)
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{
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guint i;
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guint8 *canary;
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canary = WMEM_BLOCK_TO_PRE_CANARY(block);
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for (i=0; i<WMEM_CANARY_SIZE; i++) g_assert(canary[i] == WMEM_CANARY_VALUE);
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canary = WMEM_BLOCK_TO_POST_CANARY(block);
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for (i=0; i<WMEM_CANARY_SIZE; i++) g_assert(canary[i] == WMEM_CANARY_VALUE);
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}
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/*
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* public API functions
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*/
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static void *
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wmem_strict_alloc(void *private_data, const size_t size)
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{
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wmem_strict_allocator_t *allocator;
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wmem_strict_allocator_block_t *block;
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guint i;
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guint8 *canary;
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allocator = (wmem_strict_allocator_t*) private_data;
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block = (wmem_strict_allocator_block_t *)wmem_alloc(NULL, WMEM_FULL_SIZE(size));
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block->data_len = size;
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memset(WMEM_BLOCK_TO_DATA(block), WMEM_PREFILL, block->data_len);
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canary = WMEM_BLOCK_TO_PRE_CANARY(block);
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for (i=0; i<WMEM_CANARY_SIZE; i++) canary[i] = WMEM_CANARY_VALUE;
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canary = WMEM_BLOCK_TO_POST_CANARY(block);
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for (i=0; i<WMEM_CANARY_SIZE; i++) canary[i] = WMEM_CANARY_VALUE;
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if (allocator->blocks) {
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allocator->blocks->prev = block;
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}
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block->next = allocator->blocks;
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block->prev = NULL;
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allocator->blocks = block;
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return WMEM_BLOCK_TO_DATA(block);
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}
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static void
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wmem_strict_free(void *private_data, void *ptr)
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{
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wmem_strict_allocator_t *allocator;
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wmem_strict_allocator_block_t *block;
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allocator = (wmem_strict_allocator_t*) private_data;
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block = WMEM_DATA_TO_BLOCK(ptr);
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wmem_strict_block_check_canaries(block);
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if (block->next) {
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block->next->prev = block->prev;
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}
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if (block->prev) {
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block->prev->next = block->next;
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}
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else {
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allocator->blocks = block->next;
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}
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memset(block, WMEM_POSTFILL, WMEM_FULL_SIZE(block->data_len));
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wmem_free(NULL, block);
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}
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static void *
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wmem_strict_realloc(void *private_data, void *ptr, const size_t size)
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{
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wmem_strict_allocator_block_t *block;
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void *new_ptr;
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block = WMEM_DATA_TO_BLOCK(ptr);
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/* create a new block */
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new_ptr = wmem_strict_alloc(private_data, size);
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/* copy from the old block to the new */
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if (block->data_len > size) {
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memcpy(new_ptr, ptr, size);
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}
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else {
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memcpy(new_ptr, ptr, block->data_len);
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}
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/* free the old block */
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wmem_strict_free(private_data, ptr);
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return new_ptr;
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}
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void
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wmem_strict_check_canaries(wmem_allocator_t *allocator)
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{
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wmem_strict_allocator_t *private_allocator;
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wmem_strict_allocator_block_t *block;
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if (allocator->type != WMEM_ALLOCATOR_STRICT) {
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return;
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}
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private_allocator = (wmem_strict_allocator_t*) allocator->private_data;
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block = private_allocator->blocks;
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while (block) {
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wmem_strict_block_check_canaries(block);
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block = block->next;
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}
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}
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static void
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wmem_strict_free_all(void *private_data)
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{
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wmem_strict_allocator_t *allocator;
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allocator = (wmem_strict_allocator_t*) private_data;
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while (allocator->blocks) {
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wmem_strict_free(private_data, WMEM_BLOCK_TO_DATA(allocator->blocks));
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}
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}
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static void
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wmem_strict_gc(void *private_data _U_)
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{
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/* We don't really have anything to garbage-collect, but it might be worth
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* checking our canaries at this point? */
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}
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static void
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wmem_strict_allocator_cleanup(void *private_data)
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{
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wmem_free(NULL, private_data);
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}
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void
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wmem_strict_allocator_init(wmem_allocator_t *allocator)
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{
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wmem_strict_allocator_t *strict_allocator;
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strict_allocator = wmem_new(NULL, wmem_strict_allocator_t);
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allocator->alloc = &wmem_strict_alloc;
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allocator->realloc = &wmem_strict_realloc;
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allocator->free = &wmem_strict_free;
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allocator->free_all = &wmem_strict_free_all;
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allocator->gc = &wmem_strict_gc;
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allocator->cleanup = &wmem_strict_allocator_cleanup;
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allocator->private_data = (void*) strict_allocator;
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strict_allocator->blocks = NULL;
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}
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/*
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* Editor modelines - http://www.wireshark.org/tools/modelines.html
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*
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* Local variables:
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* c-basic-offset: 4
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* tab-width: 8
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* indent-tabs-mode: nil
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* End:
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*
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* vi: set shiftwidth=4 tabstop=8 expandtab:
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* :indentSize=4:tabSize=8:noTabs=true:
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*/
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