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3265324e00
This change fixes #496 where ASAN spotted a race condition that could happen in multithreaded programs, with more than OPEN_MAX descriptors when using ZipOS or Windows NT, which require tracking open file info and this change fixes that table so it never relocates, thus allowing us to continue to enjoy the benefits of avoiding locks while reading.
65 lines
3.2 KiB
C
65 lines
3.2 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2021 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/calls/calls.h"
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#include "libc/macros.internal.h"
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#include "libc/runtime/directmap.internal.h"
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#include "libc/runtime/pc.internal.h"
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#include "libc/str/str.h"
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#include "libc/sysv/consts/map.h"
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#include "libc/sysv/consts/prot.h"
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#include "libc/sysv/errfuns.h"
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static uint64_t sys_mmap_metal_break;
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noasan struct DirectMap sys_mmap_metal(void *paddr, size_t size, int prot,
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int flags, int fd, int64_t off) {
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/* asan runtime depends on this function */
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size_t i;
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struct mman *mm;
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struct DirectMap res;
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uint64_t addr, page, *pte, *pml4t;
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mm = (struct mman *)(BANE + 0x0500);
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pml4t = __get_pml4t();
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size = ROUNDUP(size, 4096);
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addr = (uint64_t)paddr;
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if (!(flags & MAP_FIXED)) {
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for (i = 0; i < size; i += 4096) {
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pte = __get_virtual(mm, pml4t, addr, false);
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if (pte && (*pte & PAGE_V)) {
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addr = MAX(addr, sys_mmap_metal_break) + i + 4096;
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i = 0;
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}
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}
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sys_mmap_metal_break = MAX(addr + size, sys_mmap_metal_break);
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}
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for (i = 0; i < size; i += 4096) {
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page = __new_page(mm);
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pte = __get_virtual(mm, pml4t, addr + i, true);
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if (pte && page) {
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__clear_page(BANE + page);
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*pte = page | ((prot & PROT_WRITE) ? PAGE_RW : 0) | PAGE_U | PAGE_V;
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} else {
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addr = -1;
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break;
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}
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}
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res.addr = (void *)addr;
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res.maphandle = -1;
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return res;
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}
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