mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-02-07 06:53:33 +00:00
624573207e
This change doubles the performance of thread spawning. That's thanks to our new stack manager, which allows us to avoid zeroing stacks. It gives us 15µs spawns rather than 30µs spawns on Linux. Also, pthread_exit() is faster now, since it doesn't need to acquire the pthread GIL. On NetBSD, that helps us avoid allocating too many semaphores. Even if that happens we're now able to survive semaphores running out and even memory running out, when allocating *NSYNC waiter objects. I found a lot more rare bugs in the POSIX threads runtime that could cause things to crash, if you've got dozens of threads all spawning and joining dozens of threads. I want cosmo to be world class production worthy for 2025 so happy holidays all
128 lines
5.1 KiB
C
128 lines
5.1 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2021 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/errno.h"
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#include "libc/intrin/weaken.h"
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#include "libc/paths.h"
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#include "libc/runtime/runtime.h"
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#include "libc/stdio/internal.h"
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#include "libc/stdio/stdio.h"
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#include "libc/sysv/consts/f.h"
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#include "libc/sysv/consts/fd.h"
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#include "libc/sysv/consts/o.h"
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#include "libc/sysv/errfuns.h"
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#include "libc/thread/thread.h"
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/**
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* Spawns subprocess and returns pipe stream.
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*
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* The returned resource needs to be passed to pclose().
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*
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* This embeds the Cosmopolitan Command Interpreter which provides
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* Bourne-like syntax on all platforms including Windows.
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*
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* @param cmdline is a unix shell script
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* @param mode can be:
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* - `"r"` for reading from subprocess standard output
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* - `"w"` for writing to subprocess standard input
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* - `"e"` for `O_CLOEXEC` on returned file
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* @raise EINVAL if `mode` is invalid or specifies read+write
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* @raise EMFILE if process `RLIMIT_NOFILE` has been reached
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* @raise ENFILE if system-wide file limit has been reached
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* @raise ECANCELED if thread was cancelled in masked mode
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* @raise ENOMEM if we require more vespene gas
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* @raise EAGAIN if `RLIMIT_NPROC` was exceeded
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* @raise EINTR if signal was delivered
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* @cancelationpoint
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*/
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FILE *popen(const char *cmdline, const char *mode) {
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FILE *f;
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int e, rc, pid, dir, flags, pipefds[2];
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flags = fopenflags(mode);
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if ((flags & O_ACCMODE) == O_RDONLY) {
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dir = 0;
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} else if ((flags & O_ACCMODE) == O_WRONLY) {
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dir = 1;
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} else {
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einval();
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return NULL;
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}
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if (_weaken(pthread_testcancel_np) &&
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(rc = _weaken(pthread_testcancel_np)())) {
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errno = rc;
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return 0;
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}
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if (pipe2(pipefds, O_CLOEXEC) == -1)
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return NULL;
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if ((f = fdopen(pipefds[dir], mode))) {
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switch ((pid = fork())) {
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case 0:
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#pragma GCC diagnostic push
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#pragma GCC diagnostic ignored "-Wanalyzer-fd-leak"
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unassert(dup2(pipefds[!dir], !dir) == !dir);
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#pragma GCC diagnostic pop
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// we can't rely on cloexec because cocmd builtins don't execve
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if (pipefds[0] != !dir)
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unassert(!close(pipefds[0]));
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if (pipefds[1] != !dir)
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unassert(!close(pipefds[1]));
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// "The popen() function shall ensure that any streams from
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// previous popen() calls that remain open in the parent
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// process are closed in the new child process." -POSIX
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for (struct Dll *e = dll_first(__stdio.files); e;
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e = dll_next(__stdio.files, e)) {
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FILE *f2 = FILE_CONTAINER(e);
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if (f != f2 && f2->pid && f2->fd != -1) {
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close(f2->fd);
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f2->fd = -1;
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}
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}
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_Exit(_cocmd(3,
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(char *[]){
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"popen",
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"-c",
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(char *)cmdline,
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0,
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},
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environ));
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default:
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f->pid = pid;
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unassert(!close(pipefds[!dir]));
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if (!(flags & O_CLOEXEC)) {
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unassert(!fcntl(pipefds[dir], F_SETFD, 0));
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}
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return f;
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case -1:
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e = errno;
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fclose(f);
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close(pipefds[!dir]);
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errno = e;
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return NULL;
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}
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} else {
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e = errno;
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close(pipefds[0]);
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close(pipefds[1]);
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errno = e;
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return NULL;
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}
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}
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