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https://github.com/jart/cosmopolitan.git
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edd9297eba
Your Actually Portable Executables now contains a simple virtual memory that works similarly to the Linux Kernel in the sense that it maps your physical memory to negative addresses. This is needed to support mmap() and malloc(). This functionality has zero code size impact. For example the MODE=tiny LIFE.COM executable is still only 12KB in size. The APE bootloader code has also been simplified to improve readibility and further elevate the elegance by which we're able to support so many platforms thereby enhancing verifiability so that we may engender trust in this bootloading process.
52 lines
3 KiB
C
52 lines
3 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 2020 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/internal.h"
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#include "libc/dce.h"
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#include "libc/macros.h"
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#include "libc/runtime/directmap.internal.h"
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#include "libc/runtime/memtrack.h"
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#include "libc/runtime/runtime.h"
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#include "libc/sysv/errfuns.h"
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#define IP(X) (intptr_t)(X)
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#define ALIGNED(p) (!(IP(p) & (FRAMESIZE - 1)))
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#define CANONICAL(p) (-0x800000000000 <= IP(p) && IP(p) <= 0x7fffffffffff)
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/**
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* Releases memory pages.
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*
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* This function may be used to punch holes in existing mappings, but your
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* mileage may vary on Windows.
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*
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* @param addr is a pointer within any memory mapped region the process
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* has permission to control, such as address ranges returned by
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* mmap(), the program image itself, etc.
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* @param size is the amount of memory to unmap, which needs to be a
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* multiple of FRAMESIZE for anonymous mappings, because windows
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* and for files size needs to be perfect to the byte bc openbsd
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* @return 0 on success, or -1 w/ errno
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*/
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int munmap(void *addr, size_t size) {
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int rc;
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if (!ALIGNED(addr) || !CANONICAL(addr) || !size) return einval();
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if (UntrackMemoryIntervals(addr, size) == -1) return -1;
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if (IsWindows()) return 0;
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if (IsMetal()) sys_munmap_metal(addr, size);
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return sys_munmap(addr, size);
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}
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