mirror of
https://github.com/jart/cosmopolitan.git
synced 2024-05-16 18:42:39 +00:00
2ab9e9f7fd
- Introduce portable sched_getcpu() api - Support GCC's __target_clones__ feature - Make fma() go faster on x86 in default mode - Remove some asan checks from core libraries - WinMain() now ensures $HOME and $USER are defined
95 lines
3.6 KiB
C
95 lines
3.6 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/calls/internal.h"
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#include "libc/calls/state.internal.h"
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#include "libc/calls/struct/fd.internal.h"
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#include "libc/intrin/atomic.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/macros.internal.h"
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#include "libc/runtime/memtrack.internal.h"
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#include "libc/str/str.h"
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#include "libc/sysv/consts/map.h"
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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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size_t n;
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if (fd < g_fds.n) return fd;
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n = fd + 1;
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g_fds.e = _extend(g_fds.p, n * sizeof(*g_fds.p), g_fds.e, MAP_PRIVATE,
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kMemtrackFdsStart + kMemtrackFdsSize);
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g_fds.n = n;
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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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*/
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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, f1, f2;
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for (;;) {
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f1 = atomic_load_explicit(&g_fds.f, memory_order_acquire);
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for (fd = MAX(start, f1); 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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// g_fds.f isn't guarded by our mutex
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do {
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f2 = MAX(fd + 1, f1);
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} while (!atomic_compare_exchange_weak_explicit(
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&g_fds.f, &f1, f2, memory_order_release, memory_order_relaxed));
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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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*/
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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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