mirror of
https://github.com/jart/cosmopolitan.git
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7822917fc2
You can now do things like implement mutexes using futexes in your redbean lua code. This provides the fastest possible inter-process communication for your production systems when SQLite alone as ipc or things like pipes aren't sufficient.
101 lines
3.7 KiB
C
101 lines
3.7 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/assert.h"
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#include "libc/calls/calls.h"
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#include "libc/calls/internal.h"
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#include "libc/calls/state.internal.h"
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#include "libc/calls/struct/sigset.h"
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#include "libc/dce.h"
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#include "libc/intrin/cmpxchg.h"
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#include "libc/intrin/extend.internal.h"
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#include "libc/intrin/strace.internal.h"
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#include "libc/macros.internal.h"
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#include "libc/mem/mem.h"
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#include "libc/runtime/directmap.internal.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/str/str.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/consts/sig.h"
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#include "libc/sysv/errfuns.h"
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static volatile size_t mapsize;
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/**
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* Grows file descriptor array memory if needed.
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*
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* @see libc/runtime/memtrack64.txt
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* @see libc/runtime/memtrack32.txt
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* @asyncsignalsafe
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*/
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int __ensurefds_unlocked(int fd) {
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bool relocate;
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if (fd < g_fds.n) return fd;
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g_fds.n = fd + 1;
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g_fds.e = _extend(g_fds.p, g_fds.n * sizeof(*g_fds.p), g_fds.e, MAP_PRIVATE,
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kMemtrackFdsStart + kMemtrackFdsSize);
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return fd;
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}
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/**
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* Grows file descriptor array memory if needed.
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* @asyncsignalsafe
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* @threadsafe
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*/
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int __ensurefds(int fd) {
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__fds_lock();
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fd = __ensurefds_unlocked(fd);
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__fds_unlock();
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return fd;
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}
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/**
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* Finds open file descriptor slot.
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* @asyncsignalsafe
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*/
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int __reservefd_unlocked(int start) {
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int fd;
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for (;;) {
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for (fd = MAX(start, g_fds.f); fd < g_fds.n; ++fd) {
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if (!g_fds.p[fd].kind) {
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break;
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}
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}
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fd = __ensurefds_unlocked(fd);
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bzero(g_fds.p + fd, sizeof(*g_fds.p));
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if (_cmpxchg(&g_fds.p[fd].kind, kFdEmpty, kFdReserved)) {
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_cmpxchg(&g_fds.f, fd, fd + 1);
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return fd;
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}
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}
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}
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/**
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* Finds open file descriptor slot.
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* @asyncsignalsafe
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* @threadsafe
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*/
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int __reservefd(int start) {
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int fd;
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__fds_lock();
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fd = __reservefd_unlocked(start);
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__fds_unlock();
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return fd;
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}
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