mirror of
https://github.com/jart/cosmopolitan.git
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98 lines
4.2 KiB
C
98 lines
4.2 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 2022 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/assert.h"
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#include "libc/calls/calls.h"
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#include "libc/dce.h"
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#include "libc/errno.h"
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#include "libc/intrin/asan.internal.h"
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#include "libc/intrin/asancodes.h"
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#include "libc/intrin/describebacktrace.internal.h"
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#include "libc/intrin/directmap.internal.h"
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#include "libc/log/libfatal.internal.h"
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#include "libc/macros.internal.h"
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#include "libc/runtime/memtrack.internal.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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#define G FRAMESIZE
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static dontasan void *_mapframe(void *p, int f) {
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int rc, prot, flags;
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struct DirectMap dm;
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prot = PROT_READ | PROT_WRITE;
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flags = f | MAP_ANONYMOUS | MAP_FIXED;
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if ((dm = sys_mmap(p, G, prot, flags, -1, 0)).addr == p) {
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__mmi_lock();
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rc = __track_memory(&_mmi, (uintptr_t)p >> 16, (uintptr_t)p >> 16,
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dm.maphandle, prot, flags, false, false, 0, G);
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__mmi_unlock();
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if (!rc) {
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return p;
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} else {
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unassert(errno == ENOMEM);
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return 0;
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}
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} else {
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unassert(errno == ENOMEM);
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return 0;
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}
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}
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/**
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* Extends static allocation.
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*
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* This simple fixed allocator has unusual invariants
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*
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* !(p & 0xffff) && !(((p >> 3) + 0x7fff8000) & 0xffff)
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*
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* which must be the case when selecting a starting address. We also
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* make the assumption that allocations can only grow monotonically.
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* Furthermore allocations shall never be removed or relocated.
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*
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* @param p points to start of memory region
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* @param n specifies how many bytes are needed
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* @param e points to end of memory that's allocated
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* @param h is highest address to which `e` may grow
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* @param f should be `MAP_PRIVATE` or `MAP_SHARED`
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* @return new value for `e` or null w/ errno
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* @raise ENOMEM if we require more vespene gas
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*/
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dontasan void *_extend(void *p, size_t n, void *e, int f, intptr_t h) {
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char *q;
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unassert(!((uintptr_t)SHADOW(p) & (G - 1)));
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unassert((uintptr_t)p + (G << kAsanScale) <= h);
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// TODO(jart): Make this spin less in non-ASAN mode.
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for (q = e; q < ((char *)p + n); q += 8) {
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if (!((uintptr_t)q & (G - 1))) {
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unassert(q + G <= (char *)h);
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if (!_mapframe(q, f)) return 0;
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if (IsAsan()) {
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if (!((uintptr_t)SHADOW(q) & (G - 1))) {
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if (!_mapframe(SHADOW(q), f)) return 0;
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__asan_poison(q, G << kAsanScale, kAsanProtected);
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}
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}
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}
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if (IsAsan()) {
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*SHADOW(q) = 0;
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}
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}
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return q;
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}
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