mirror of
https://github.com/jart/cosmopolitan.git
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70 lines
3.1 KiB
C
70 lines
3.1 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/intrin/weaken.h"
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#include "libc/calls/calls.h"
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#include "libc/errno.h"
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#include "libc/nexgen32e/bsr.h"
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#include "libc/runtime/runtime.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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/**
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* Helper function for allocating anonymous mapping.
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*
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* This function is equivalent to:
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*
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* mmap(NULL, mapsize, PROT_READ | PROT_WRITE,
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* MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
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*
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* If mmap() fails, possibly because the parent process did this:
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*
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* if (!vfork()) {
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* setrlimit(RLIMIT_AS, &(struct rlimit){maxbytes, maxbytes});
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* execv(prog, (char *const[]){prog, 0});
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* }
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* wait(0);
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*
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* Then this function will call:
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*
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* __oom_hook(size);
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*
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* If it's linked. The LIBC_TESTLIB library provides an implementation,
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* which can be installed as follows:
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*
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* int main() {
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* InstallQuotaHandlers();
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* // ...
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* }
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*
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* That is performed automatically for unit test executables.
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*
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* @return memory map address on success, or null w/ errno
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*/
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void *_mapanon(size_t size) {
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void *m;
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m = mmap(0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
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if (m != MAP_FAILED) {
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return m;
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}
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if (errno == ENOMEM && weaken(__oom_hook)) {
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weaken(__oom_hook)(size);
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}
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return 0;
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}
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