mirror of
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
107 lines
4.3 KiB
C
107 lines
4.3 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│ vi: set et 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/dce.h"
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#include "libc/fmt/conv.h"
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#include "libc/fmt/itoa.h"
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#include "libc/intrin/bsr.h"
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#include "libc/intrin/describeflags.h"
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#include "libc/intrin/kprintf.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/runtime/runtime.h"
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#include "libc/sysv/consts/auxv.h"
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// this will usually return 12 since x86 pml4t uses a 47 bit address
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// space in userspace, and decent arm machines uses a 48 bit address
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// space. however it could go lower on embedded devices. it can also
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// rise higher on expensive x86 machines with pml5t, if user uses it
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static int get_address_digits(int pagesz) {
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int max_bits = 0;
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for (struct Tree *e = tree_first(__maps.maps); e; e = tree_next(e)) {
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struct Map *map = MAP_TREE_CONTAINER(e);
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char *end = map->addr + ((map->size + pagesz - 1) & -pagesz);
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int bits = bsrll((uintptr_t)end) + 1;
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if (bits > max_bits)
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max_bits = bits;
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}
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return ((max_bits + 3) & -4) / 4;
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}
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/**
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* Prints memory mappings known to cosmo.
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*/
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void __print_maps(size_t limit) {
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__maps_lock();
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char sb[16];
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char mappingbuf[8];
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struct Map *last = 0;
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int pagesz = __pagesize;
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int gransz = __gransize;
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int digs = get_address_digits(pagesz);
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for (struct Tree *e = tree_first(__maps.maps); e; e = tree_next(e)) {
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struct Map *map = MAP_TREE_CONTAINER(e);
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// show gaps between maps
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if (last) {
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char *beg = last->addr + ((last->size + gransz - 1) & -gransz);
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char *end = map->addr;
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if (end > beg) {
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size_t gap = end - beg;
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sizefmt(sb, gap, 1024);
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kprintf("%0*lx-%0*lx %sb\n", digs, beg, digs, end, sb);
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}
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}
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last = map;
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// show mapping
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kprintf("%0*lx-%0*lx %!s", digs, map->addr, digs, map->addr + map->size,
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_DescribeMapping(mappingbuf, map->prot, map->flags));
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sizefmt(sb, map->size, 1024);
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kprintf(" %!sb", sb);
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if (IsWindows()) {
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switch (map->hand) {
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case MAPS_RESERVATION:
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kprintf(" reservation");
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break;
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case MAPS_SUBREGION:
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break;
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case MAPS_VIRTUAL:
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kprintf(" virtual");
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break;
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default:
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kprintf(" hand=%ld", map->hand);
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break;
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}
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}
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if (map->iscow)
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kprintf(" cow");
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if (map->readonlyfile)
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kprintf(" readonlyfile");
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kprintf("\n");
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// stay beneath our limit
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if (!--limit)
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break;
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}
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// print summary
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kprintf("# %'zu bytes in %'zu mappings\n", __maps.pages * pagesz,
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__maps.count);
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__maps_unlock();
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}
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