mirror of
https://github.com/jart/cosmopolitan.git
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276 lines
10 KiB
C
276 lines
10 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 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/assert.h"
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#include "libc/calls/calls.h"
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#include "libc/calls/internal.h"
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#include "libc/calls/sig.internal.h"
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#include "libc/calls/state.internal.h"
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#include "libc/calls/struct/sigaction.h"
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#include "libc/calls/struct/sigset.internal.h"
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#include "libc/calls/struct/timespec.h"
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#include "libc/dce.h"
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#include "libc/errno.h"
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#include "libc/intrin/atomic.h"
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#include "libc/intrin/strace.h"
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#include "libc/macros.h"
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#include "libc/mem/mem.h"
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#include "libc/nt/console.h"
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#include "libc/nt/enum/filetype.h"
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#include "libc/nt/errors.h"
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#include "libc/nt/files.h"
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#include "libc/nt/ipc.h"
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#include "libc/nt/runtime.h"
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#include "libc/nt/struct/pollfd.h"
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#include "libc/nt/synchronization.h"
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#include "libc/nt/thread.h"
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#include "libc/nt/thunk/msabi.h"
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#include "libc/nt/winsock.h"
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#include "libc/runtime/runtime.h"
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#include "libc/sock/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/stdio/sysparam.h"
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#include "libc/sysv/consts/o.h"
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#include "libc/sysv/consts/poll.h"
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#include "libc/sysv/consts/sig.h"
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#include "libc/sysv/errfuns.h"
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#include "libc/thread/posixthread.internal.h"
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#include "libc/thread/tls.h"
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#ifdef __x86_64__
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#define POLL_INTERVAL_MS 10
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// <sync libc/sysv/consts.sh>
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#define POLLERR_ 0x0001 // implied in events
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#define POLLHUP_ 0x0002 // implied in events
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#define POLLNVAL_ 0x0004 // implied in events
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#define POLLIN_ 0x0300
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#define POLLRDNORM_ 0x0100
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#define POLLRDBAND_ 0x0200
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#define POLLOUT_ 0x0010
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#define POLLWRNORM_ 0x0010
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#define POLLWRBAND_ 0x0020 // MSDN undocumented
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#define POLLPRI_ 0x0400 // MSDN unsupported
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// </sync libc/sysv/consts.sh>
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// Polls on the New Technology.
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//
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// This function is used to implement poll() and select(). You may poll
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// on sockets, files and the console at the same time. We also poll for
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// both signals and posix thread cancelation, while the poll is polling
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static textwindows int sys_poll_nt_impl(struct pollfd *fds, uint64_t nfds,
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uint32_t *ms, sigset_t sigmask) {
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bool ok;
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uint64_t millis;
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uint32_t cm, avail, waitfor;
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struct sys_pollfd_nt pipefds[64];
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struct sys_pollfd_nt sockfds[64];
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int pipeindices[ARRAYLEN(pipefds)];
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int sockindices[ARRAYLEN(sockfds)];
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struct timespec deadline, remain, now;
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int i, rc, sn, pn, gotinvals, gotpipes, gotsocks;
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waitfor = ms ? *ms : -1u;
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deadline = timespec_add(timespec_mono(), timespec_frommillis(waitfor));
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// do the planning
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// we need to read static variables
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// we might need to spawn threads and open pipes
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__fds_lock();
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for (gotinvals = rc = sn = pn = i = 0; i < nfds; ++i) {
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if (fds[i].fd < 0)
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continue;
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if (__isfdopen(fds[i].fd)) {
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if (__isfdkind(fds[i].fd, kFdSocket)) {
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if (sn < ARRAYLEN(sockfds)) {
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// WSAPoll whines if we pass POLLNVAL, POLLHUP, or POLLERR.
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sockindices[sn] = i;
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sockfds[sn].handle = g_fds.p[fds[i].fd].handle;
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sockfds[sn].events =
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fds[i].events & (POLLRDNORM_ | POLLRDBAND_ | POLLWRNORM_);
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sockfds[sn].revents = 0;
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++sn;
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} else {
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// too many socket fds
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rc = e2big();
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break;
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}
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} else if (pn < ARRAYLEN(pipefds)) {
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pipeindices[pn] = i;
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pipefds[pn].handle = g_fds.p[fds[i].fd].handle;
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pipefds[pn].events = 0;
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pipefds[pn].revents = 0;
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switch (g_fds.p[fds[i].fd].flags & O_ACCMODE) {
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case O_RDONLY:
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pipefds[pn].events = fds[i].events & POLLIN_;
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break;
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case O_WRONLY:
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pipefds[pn].events = fds[i].events & POLLOUT_;
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break;
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case O_RDWR:
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pipefds[pn].events = fds[i].events & (POLLIN_ | POLLOUT_);
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break;
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default:
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break;
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}
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++pn;
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} else {
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// too many non-socket fds
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rc = e2big();
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break;
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}
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} else {
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++gotinvals;
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}
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}
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__fds_unlock();
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if (rc)
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// failed to create a polling solution
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return rc;
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// perform the i/o and sleeping and looping
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for (;;) {
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// see if input is available on non-sockets
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for (gotpipes = i = 0; i < pn; ++i) {
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if (pipefds[i].events & POLLWRNORM_)
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// we have no way of polling if a non-socket is writeable yet
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// therefore we assume that if it can happen, it shall happen
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pipefds[i].revents |= POLLWRNORM_;
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if (GetFileType(pipefds[i].handle) == kNtFileTypePipe) {
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ok = PeekNamedPipe(pipefds[i].handle, 0, 0, 0, &avail, 0);
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POLLTRACE("PeekNamedPipe(%ld, 0, 0, 0, [%'u], 0) → {%hhhd, %d}",
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pipefds[i].handle, avail, ok, GetLastError());
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if (ok) {
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if (avail)
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pipefds[i].revents |= POLLRDNORM_;
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} else if (GetLastError() == kNtErrorHandleEof ||
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GetLastError() == kNtErrorBrokenPipe) {
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pipefds[i].revents &= ~POLLWRNORM_;
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pipefds[i].revents |= POLLHUP_;
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} else {
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pipefds[i].revents &= ~POLLWRNORM_;
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pipefds[i].revents |= POLLERR_;
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}
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} else if (GetConsoleMode(pipefds[i].handle, &cm)) {
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// some programs like bash like to poll([stdin], 1, -1) so let's
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// avoid busy looping in such cases. we could generalize this to
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// always avoid busy loops, but we'd need poll to launch threads
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if (pn == 1 && sn == 0 && (pipefds[i].events & POLLRDNORM_)) {
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int err = errno;
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switch (CountConsoleInputBytesBlocking(waitfor, sigmask)) {
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case -1:
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if (errno == EINTR || errno == ECANCELED)
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return -1;
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errno = err;
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pipefds[i].revents &= ~POLLWRNORM_;
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pipefds[i].revents |= POLLERR_;
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break;
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case 0:
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pipefds[i].revents &= ~POLLWRNORM_;
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pipefds[i].revents |= POLLHUP_;
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break;
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default:
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pipefds[i].revents |= POLLRDNORM_;
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break;
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}
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} else {
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switch (CountConsoleInputBytes()) {
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case 0:
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break;
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case -1:
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pipefds[i].revents &= ~POLLWRNORM_;
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pipefds[i].revents |= POLLHUP_;
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break;
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default:
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pipefds[i].revents |= POLLRDNORM_;
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break;
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}
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}
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} else {
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// we have no way of polling if a non-socket is readable yet
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// therefore we assume that if it can happen it shall happen
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pipefds[i].revents |= POLLRDNORM_;
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}
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if (!(pipefds[i].events & POLLRDNORM_))
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pipefds[i].revents &= ~POLLRDNORM_;
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if (pipefds[i].revents)
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++gotpipes;
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}
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// if we haven't found any good results yet then here we
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// compute a small time slice we don't mind sleeping for
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if (sn) {
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if ((gotsocks = WSAPoll(sockfds, sn, 0)) == -1)
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return __winsockerr();
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} else {
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gotsocks = 0;
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}
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// add some artificial delay, which we use as an opportunity to also
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// check for pending signals, thread cancelation, etc.
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waitfor = 0;
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if (!gotinvals && !gotsocks && !gotpipes) {
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now = timespec_mono();
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if (timespec_cmp(now, deadline) < 0) {
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remain = timespec_sub(deadline, now);
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millis = timespec_tomillis(remain);
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waitfor = MIN(millis, 0xffffffffu);
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waitfor = MIN(waitfor, POLL_INTERVAL_MS);
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if (waitfor) {
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POLLTRACE("poll() sleeping for %'d out of %'lu ms", waitfor,
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timespec_tomillis(remain));
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if (_park_norestart(waitfor, sigmask) == -1)
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return -1; // eintr, ecanceled, etc.
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}
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}
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}
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// we gave all the sockets and all the named pipes a shot
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// if we found anything at all then it's time to end work
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if (gotinvals || gotpipes || gotsocks || !waitfor)
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break;
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}
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// the system call is going to succeed
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// it's now ok to start setting the output memory
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for (i = 0; i < nfds; ++i) {
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if (fds[i].fd < 0 || __isfdopen(fds[i].fd)) {
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fds[i].revents = 0;
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} else {
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fds[i].revents = POLLNVAL_;
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}
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}
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for (i = 0; i < pn; ++i)
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fds[pipeindices[i]].revents = pipefds[i].revents;
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for (i = 0; i < sn; ++i)
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fds[sockindices[i]].revents = sockfds[i].revents;
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// and finally return
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return gotinvals + gotpipes + gotsocks;
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}
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textwindows int sys_poll_nt(struct pollfd *fds, uint64_t nfds, uint32_t *ms,
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const sigset_t *sigmask) {
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int rc;
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BLOCK_SIGNALS;
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rc = sys_poll_nt_impl(fds, nfds, ms, sigmask ? *sigmask : 0);
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ALLOW_SIGNALS;
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return rc;
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}
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#endif /* __x86_64__ */
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