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https://github.com/jart/cosmopolitan.git
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ff77f2a6af
- This change fixes a bug that allowed unbuffered printf() output (to streams like stderr) to be truncated. This regression was introduced some time between now and the last release. - POSIX specifies all functions as thread safe by default. This change works towards cleaning up our use of the @threadsafe / @threadunsafe documentation annotations to reflect that. The goal is (1) to use @threadunsafe to document functions which POSIX say needn't be thread safe, and (2) use @threadsafe to document functions that we chose to implement as thread safe even though POSIX didn't mandate it. - Tidy up the clock_gettime() implementation. We're now trying out a cleaner approach to system call support that aims to maintain the Linux errno convention as long as possible. This also fixes bugs that existed previously, where the vDSO errno wasn't being translated properly. The gettimeofday() system call is now a wrapper for clock_gettime(), which reduces bloat in apps that use both. - The recently-introduced improvements to the execute bit on Windows has had bugs fixed. access(X_OK) on a directory on Windows now succeeds. fstat() will now perform the MZ/#! ReadFile() operation correctly. - Windows.h is no longer included in libc/isystem/, because it confused PCRE's build system into thinking Cosmopolitan is a WIN32 platform. Cosmo's Windows.h polyfill was never even really that good, since it only defines a subset of the subset of WIN32 APIs that Cosmo defines. - The setlongerjmp() / longerjmp() APIs are removed. While they're nice APIs that are superior to the standardized setjmp / longjmp functions, they weren't superior enough to not be dead code in the monorepo. If you use these APIs, please file an issue and they'll be restored. - The .com appending magic has now been removed from APE Loader.
92 lines
4.7 KiB
C
92 lines
4.7 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 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/bo.internal.h"
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#include "libc/calls/cp.internal.h"
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#include "libc/dce.h"
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#include "libc/intrin/asan.internal.h"
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#include "libc/intrin/strace.internal.h"
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#include "libc/sock/struct/pollfd.h"
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#include "libc/sock/struct/pollfd.internal.h"
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#include "libc/stdckdint.h"
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#include "libc/sysv/errfuns.h"
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/**
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* Waits for something to happen on multiple file descriptors at once.
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*
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* Warning: XNU has an inconsistency with other platforms. If you have
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* pollfds with fd≥0 and none of the meaningful events flags are added
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* e.g. POLLIN then XNU won't check for POLLNVAL. This matters because
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* one of the use-cases for poll() is quickly checking for open files.
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*
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* Note: Polling works best on Windows for sockets. We're able to poll
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* input on named pipes. But for anything that isn't a socket, or pipe
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* with POLLIN, (e.g. regular file) then POLLIN/POLLOUT are always set
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* into revents if they're requested, provided they were opened with a
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* mode that permits reading and/or writing.
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*
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* Note: Windows has a limit of 64 file descriptors and ENOMEM with -1
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* is returned if that limit is exceeded. In practice the limit is not
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* this low. For example, pollfds with fd<0 don't count. So the caller
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* could flip the sign bit with a short timeout, to poll a larger set.
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*
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* @param fds[𝑖].fd should be a socket, input pipe, or conosle input
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* and if it's a negative number then the entry is ignored
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* @param fds[𝑖].events flags can have POLLIN, POLLOUT, POLLPRI,
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* POLLRDNORM, POLLWRNORM, POLLRDBAND, POLLWRBAND as well as
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* POLLERR, POLLHUP, and POLLNVAL although the latter are
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* always implied (assuming fd≥0) so they're ignored here
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* @param timeout_ms if 0 means don't wait and -1 means wait forever
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* @return number of items fds whose revents field has been set to
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* nonzero to describe its events, or 0 if the timeout elapsed,
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* or -1 w/ errno
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* @return fds[𝑖].revents is always zero initializaed and then will
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* be populated with POLL{IN,OUT,PRI,HUP,ERR,NVAL} if something
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* was determined about the file descriptor
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* @raise ECANCELED if thread was cancelled in masked mode
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* @raise EINTR if signal was delivered
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* @cancellationpoint
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* @asyncsignalsafe
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* @norestart
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*/
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int poll(struct pollfd *fds, size_t nfds, int timeout_ms) {
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int rc;
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size_t n;
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BEGIN_CANCELLATION_POINT;
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if (IsAsan() &&
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(ckd_mul(&n, nfds, sizeof(struct pollfd)) || !__asan_is_valid(fds, n))) {
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rc = efault();
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} else if (!IsWindows()) {
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if (!IsMetal()) {
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rc = sys_poll(fds, nfds, timeout_ms);
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} else {
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rc = sys_poll_metal(fds, nfds, timeout_ms);
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}
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} else {
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BEGIN_BLOCKING_OPERATION;
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uint32_t ms = timeout_ms >= 0 ? timeout_ms : -1u;
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rc = sys_poll_nt(fds, nfds, &ms, 0);
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END_BLOCKING_OPERATION;
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}
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END_CANCELLATION_POINT;
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STRACE("poll(%s, %'zu, %'d) → %d% lm", DescribePollFds(rc, fds, nfds), nfds,
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timeout_ms, rc);
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return rc;
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}
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