mirror of
https://github.com/jart/cosmopolitan.git
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853b6c3864
- Wrap clock_getres() - Wrap sched_setscheduler() - Make sleep() api conformant - Polyfill sleep() using select() - Improve clock_gettime() polyfill - Make nanosleep() POSIX conformant - Slightly improve some DNS functions - Further strengthen pledge() sandboxing - Improve rounding of timeval / timespec - Allow layering of pledge() calls on Linux - Polyfill sched_yield() using select() on XNU - Delete more system constants we probably don't need
106 lines
5.3 KiB
C
106 lines
5.3 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set 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/sched-sysv.internal.h"
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#include "libc/calls/strace.internal.h"
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#include "libc/calls/struct/sched_param.h"
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#include "libc/dce.h"
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#include "libc/intrin/describeflags.internal.h"
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#include "libc/nexgen32e/threaded.h"
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#include "libc/str/str.h"
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#include "libc/sysv/errfuns.h"
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/**
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* Sets scheduling policy of process, e.g.
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*
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* struct sched_param p = {sched_get_priority_max(SCHED_OTHER)};
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* LOGIFNEG1(sched_setscheduler(0, SCHED_OTHER, &p));
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*
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* Processes with numerically higher priority values are scheduled
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* before processes with numerically lower priority values.
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*
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* @param pid is the id of the process whose scheduling policy should be
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* changed. This applies to all threads associated with the process.
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* Linux is special; the kernel treats this as a thread id (noting
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* that `getpid() == gettid()` is always the case on Linux for the
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* main thread) and will only take effect for the specified tid.
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* Therefore this function is POSIX-compliant iif `!__threaded`.
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* Setting `pid` to zero means the same thing as getpid().
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*
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* @param policy specifies the kernel's timesharing strategy.
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*
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* The `policy` must have one of:
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*
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* - `SCHED_OTHER` (or `SCHED_NORMAL`) for the default policy
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* - `SCHED_RR` for real-time round-robin scheduling
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* - `SCHED_FIFO` for real-time first-in first-out scheduling
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* - `SCHED_BATCH` for "batch" style execution of processes if
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* supported (Linux), otherwise it's treated as `SCHED_OTHER`
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* - `SCHED_IDLE` for running very low priority background jobs
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* if it's supported (Linux), otherwise this is `SCHED_OTHER`
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*
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* The `policy` may optionally bitwise-or any one of:
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*
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* - `SCHED_RESET_ON_FORK` will cause the scheduling policy to be
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* automatically reset to `SCHED_NORMAL` upon fork() if supported;
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* otherwise this flag is polyfilled as zero, so that it may be
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* safely used (without having to check if the o/s is Linux).
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*
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* @param param must be set to the scheduler parameter, which should be
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* greater than or equal to sched_get_priority_min(policy) and less
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* than or equal to sched_get_priority_max(policy). Linux allows the
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* static priority range 1 to 99 for the `SCHED_FIFO` and `SCHED_RR`
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* policies, and the priority 0 for the remaining policies.
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*
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* @return the former scheduling policy of the specified process. If
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* this function fails, then the scheduling policy is not changed,
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* and -1 w/ errno is returned.
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*
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* @raise ENOSYS on XNU, Windows, OpenBSD
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* @raise EPERM if not authorized to use scheduler in question (e.g.
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* trying to use a real-time scheduler as non-root on Linux) or
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* possibly because pledge() was used and isn't allowing this
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* @raise EINVAL if `param` is NULL
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* @raise EINVAL if `policy` is invalid
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* @raise EINVAL if `param` has value out of ranges defined by `policy`
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*/
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int sched_setscheduler(int pid, int policy, const struct sched_param *param) {
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int rc, old;
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if (IsNetbsd()) {
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rc = sys_sched_getscheduler_netbsd(pid);
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} else {
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rc = sys_sched_getscheduler(pid);
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}
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if (rc != -1) {
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old = rc;
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if (IsNetbsd()) {
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rc = sys_sched_setparam_netbsd(pid, P_ALL_LWPS, policy, param);
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} else {
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rc = sys_sched_setscheduler(pid, policy, param);
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}
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if (rc != -1) {
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rc = old;
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}
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}
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STRACE("sched_setscheduler(%d, %s, %s) → %d% m", pid,
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DescribeSchedPolicy(policy), DescribeSchedParam(param), rc);
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return rc;
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}
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