mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-01-31 19:43:32 +00:00
3f0bcdc3ef
- Exhaustively document cancellation points - Rename SIGCANCEL to SIGTHR just like BSDs - Further improve POSIX thread cancellations - Ensure asynchronous cancellations work correctly - Elevate the quality of getrandom() and getentropy() - Make futexes cancel correctly on OpenBSD 6.x and 7.x - Add reboot.com and shutdown.com to examples directory - Remove underscore prefix from awesome timespec_*() APIs - Create assertions that help verify our cancellation points - Remove bad timespec APIs (cmp generalizes eq/ne/gt/gte/lt/lte)
99 lines
4.2 KiB
C
99 lines
4.2 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 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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* @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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* @cancellationpoint
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* @threadsafe
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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) 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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_unassert(dup2(pipefds[!dir], !dir) == !dir);
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// we can't rely on cloexec because cocmd builtins don't execve
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if (pipefds[0] != !dir) _unassert(!close(pipefds[0]));
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if (pipefds[1] != !dir) _unassert(!close(pipefds[1]));
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_Exit(_cocmd(3, (char *[]){"popen", "-c", cmdline, 0}, 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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return f;
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case -1:
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e = errno;
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_unassert(!fclose(f));
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_unassert(!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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_unassert(!close(pipefds[0]));
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_unassert(!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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