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https://github.com/jart/cosmopolitan.git
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0b3c81dd4e
This change makes fork() go nearly as fast as sys_fork() on UNIX. As for Windows this change shaves about 4-5ms off fork() + wait() latency. This is accomplished by using WriteProcessMemory() from the parent process to setup the address space of a suspended process; it is better than a pipe
57 lines
2.8 KiB
C
57 lines
2.8 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│ vi: set et 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/intrin/describeflags.h"
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#include "libc/intrin/maps.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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static char DescribeMapType(int flags) {
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switch (flags & MAP_TYPE) {
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case MAP_FILE:
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if (flags & MAP_NOFORK)
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return 'i'; // executable image
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return '-';
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case MAP_PRIVATE:
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if (flags & MAP_NOFORK)
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return 'w'; // windows memory
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return 'p';
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case MAP_SHARED:
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return 's';
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default:
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return '?';
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}
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}
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char *DescribeProt(char p[4], int prot) {
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p[0] = (prot & PROT_READ) ? 'r' : '-';
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p[1] = (prot & PROT_WRITE) ? 'w' : '-';
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p[2] = (prot & PROT_EXEC) ? 'x' : '-';
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p[3] = 0;
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return p;
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}
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const char *_DescribeMapping(char p[8], int prot, int flags) {
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/* asan runtime depends on this function */
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DescribeProt(p, prot);
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p[3] = DescribeMapType(flags);
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p[4] = (flags & MAP_ANONYMOUS) ? 'a' : '-';
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p[5] = 0;
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return p;
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}
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