mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-01-31 19:43:32 +00:00
c995838e5c
- Clean up sigaction() code - Add a port scanner example - Introduce a ParseCidr() API - Clean up our futex abstraction code - Fix a harmless integer overflow in ParseIp() - Use kernel semaphores on NetBSD to make threads much faster
47 lines
2.8 KiB
C
47 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 net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2022 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/calls.h"
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#include "libc/dce.h"
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#include "libc/intrin/atomic.h"
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#include "libc/limits.h"
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#include "libc/sysv/errfuns.h"
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#include "libc/thread/semaphore.h"
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#include "third_party/nsync/mu_semaphore.h"
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/**
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* Initializes unnamed semaphore.
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*
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* Calling sem_init() on an already initialized semaphore is undefined.
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*
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* @param sem should make its way to sem_destroy() if this succeeds
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* @param pshared if semaphore may be shared between processes, provided
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* `sem` is backed by `mmap(MAP_ANONYMOUS | MAP_SHARED)` memory
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* @param value is initial count of semaphore
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* @return 0 on success, or -1 w/ errno
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* @raise EINVAL if `value` exceeds `SEM_VALUE_MAX`
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*/
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int sem_init(sem_t *sem, int pshared, unsigned value) {
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if (value > SEM_VALUE_MAX) return einval();
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sem->sem_magic = SEM_MAGIC_UNNAMED;
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atomic_store_explicit(&sem->sem_value, value, memory_order_relaxed);
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sem->sem_pshared = !!pshared;
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sem->sem_pid = getpid();
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sem->sem_waiters = 0;
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return 0;
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}
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