/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/assert.h"
#include "libc/calls/calls.h"
#include "libc/calls/internal.h"
#include "libc/calls/sig.internal.h"
#include "libc/calls/state.internal.h"
#include "libc/calls/struct/sigaction.h"
#include "libc/calls/struct/timespec.h"
#include "libc/dce.h"
#include "libc/errno.h"
#include "libc/intrin/atomic.h"
#include "libc/intrin/bits.h"
#include "libc/intrin/strace.internal.h"
#include "libc/macros.internal.h"
#include "libc/mem/mem.h"
#include "libc/nt/console.h"
#include "libc/nt/enum/filetype.h"
#include "libc/nt/errors.h"
#include "libc/nt/files.h"
#include "libc/nt/ipc.h"
#include "libc/nt/runtime.h"
#include "libc/nt/struct/pollfd.h"
#include "libc/nt/synchronization.h"
#include "libc/nt/thread.h"
#include "libc/nt/thunk/msabi.h"
#include "libc/nt/winsock.h"
#include "libc/sock/internal.h"
#include "libc/sock/struct/pollfd.h"
#include "libc/sock/struct/pollfd.internal.h"
#include "libc/sysv/consts/o.h"
#include "libc/sysv/consts/poll.h"
#include "libc/sysv/consts/sig.h"
#include "libc/sysv/errfuns.h"
#include "libc/thread/posixthread.internal.h"
#include "libc/thread/tls.h"
#ifdef __x86_64__
// Polls on the New Technology.
//
// This function is used to implement poll() and select(). You may poll
// on both sockets and files at the same time. We also poll for signals
// while poll is polling.
textwindows int sys_poll_nt(struct pollfd *fds, uint64_t nfds, uint32_t *ms,
const sigset_t *sigmask) {
bool ok;
uint64_t m;
bool interrupted;
sigset_t oldmask;
uint32_t cm, avail, waitfor;
struct sys_pollfd_nt pipefds[8];
struct sys_pollfd_nt sockfds[64];
int pipeindices[ARRAYLEN(pipefds)];
int sockindices[ARRAYLEN(sockfds)];
int i, rc, sn, pn, gotinvals, gotpipes, gotsocks;
#if IsModeDbg()
struct timespec noearlier =
timespec_add(timespec_real(), timespec_frommillis(ms ? *ms : -1u));
#endif
// do the planning
// we need to read static variables
// we might need to spawn threads and open pipes
m = atomic_exchange(&__get_tls()->tib_sigmask, -1);
__fds_lock();
for (gotinvals = rc = sn = pn = i = 0; i < nfds; ++i) {
if (fds[i].fd < 0) continue;
if (__isfdopen(fds[i].fd)) {
if (__isfdkind(fds[i].fd, kFdSocket)) {
if (sn < ARRAYLEN(sockfds)) {
// the magnums for POLLIN/OUT/PRI on NT include the other ones too
// we need to clear ones like POLLNVAL or else WSAPoll shall whine
sockindices[sn] = i;
sockfds[sn].handle = g_fds.p[fds[i].fd].handle;
sockfds[sn].events = fds[i].events & (POLLPRI | POLLIN | POLLOUT);
sockfds[sn].revents = 0;
++sn;
} else {
// too many socket fds
rc = enomem();
break;
}
} else if (pn < ARRAYLEN(pipefds)) {
pipeindices[pn] = i;
pipefds[pn].handle = g_fds.p[fds[i].fd].handle;
pipefds[pn].events = 0;
pipefds[pn].revents = 0;
switch (g_fds.p[fds[i].fd].flags & O_ACCMODE) {
case O_RDONLY:
pipefds[pn].events = fds[i].events & POLLIN;
break;
case O_WRONLY:
pipefds[pn].events = fds[i].events & POLLOUT;
break;
case O_RDWR:
pipefds[pn].events = fds[i].events & (POLLIN | POLLOUT);
break;
default:
__builtin_unreachable();
}
++pn;
} else {
// too many non-socket fds
rc = enomem();
break;
}
} else {
++gotinvals;
}
}
__fds_unlock();
atomic_store_explicit(&__get_tls()->tib_sigmask, m, memory_order_release);
if (rc) {
// failed to create a polling solution
goto Finished;
}
// perform the i/o and sleeping and looping
for (;;) {
// see if input is available on non-sockets
for (gotpipes = i = 0; i < pn; ++i) {
if (pipefds[i].events & POLLOUT) {
// we have no way of polling if a non-socket is writeable yet
// therefore we assume that if it can happen, it shall happen
pipefds[i].revents |= POLLOUT;
}
if (pipefds[i].events & POLLIN) {
if (GetFileType(pipefds[i].handle) == kNtFileTypePipe) {
ok = PeekNamedPipe(pipefds[i].handle, 0, 0, 0, &avail, 0);
POLLTRACE("PeekNamedPipe(%ld, 0, 0, 0, [%'u], 0) → %hhhd% m",
pipefds[i].handle, avail, ok);
if (ok) {
if (avail) {
pipefds[i].revents |= POLLIN;
}
} else {
pipefds[i].revents |= POLLERR;
}
} else if (GetConsoleMode(pipefds[i].handle, &cm)) {
if (CountConsoleInputBytes(pipefds[i].handle)) {
pipefds[i].revents |= POLLIN;
}
} else {
// we have no way of polling if a non-socket is readable yet
// therefore we assume that if it can happen it shall happen
pipefds[i].revents |= POLLIN;
}
}
if (pipefds[i].revents) {
++gotpipes;
}
}
// if we haven't found any good results yet then here we
// compute a small time slice we don't mind sleeping for
if (sn) {
if ((gotsocks = WSAPoll(sockfds, sn, 0)) == -1) {
return __winsockerr();
}
} else {
gotsocks = 0;
}
waitfor = MIN(__SIG_POLL_INTERVAL_MS, *ms);
if (!gotinvals && !gotsocks && !gotpipes && waitfor) {
POLLTRACE("poll() sleeping for %'d out of %'u ms", waitfor, *ms);
struct PosixThread *pt = _pthread_self();
pt->abort_errno = 0;
if (sigmask) __sig_mask(SIG_SETMASK, sigmask, &oldmask);
interrupted = _check_interrupts(0) || __pause_thread(waitfor);
if (sigmask) __sig_mask(SIG_SETMASK, &oldmask, 0);
if (interrupted) return -1;
if (*ms != -1u) {
if (waitfor < *ms) {
*ms -= waitfor;
} else {
*ms = 0;
}
}
}
// we gave all the sockets and all the named pipes a shot
// if we found anything at all then it's time to end work
if (gotinvals || gotpipes || gotsocks || !*ms) {
break;
}
}
// the system call is going to succeed
// it's now ok to start setting the output memory
for (i = 0; i < nfds; ++i) {
if (fds[i].fd < 0 || __isfdopen(fds[i].fd)) {
fds[i].revents = 0;
} else {
fds[i].revents = POLLNVAL;
}
}
for (i = 0; i < pn; ++i) {
fds[pipeindices[i]].revents = pipefds[i].revents;
}
for (i = 0; i < sn; ++i) {
fds[sockindices[i]].revents = sockfds[i].revents;
}
// and finally return
rc = gotinvals + gotpipes + gotsocks;
Finished:
#if IsModeDbg()
struct timespec ended = timespec_real();
if (!rc && timespec_cmp(ended, noearlier) < 0) {
STRACE("poll() ended %'ld ns too soon!",
timespec_tonanos(timespec_sub(noearlier, ended)));
}
#endif
return rc;
}
#endif /* __x86_64__ */