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Support non-blocking i/o across platforms

Browse source 
This change introduces new tests for `O_NONBLOCK` and `SOCK_NONBLOCK` to
confirm that non-blocking i/o is now working on all supported platforms,
including Windows. For example, you can now say on Windows, MacOS, etc.:

    socket(AF_INET, SOCK_STREAM | SOCK_NONBLOCK, IPPROTO_TCP);

To create a non-blocking IPv4 TCP socket. Or you can enable non-blocking
i/o on an existing socket / pipe / etc. file descriptor by calling fcntl

    fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) | O_NONBLOCK);

This functionality is polyfilled on older Linux kernels too, e.g. RHEL5.
Now that fcntl() support is much better the FIOCLEX / FIONCLEX polyfills
for ioctl() have been removed since they're ugly non-POSIX diameond APIs

This change fixes a weakness in kprintf() that was causing Windows trace
tools to frequently crash.
This commit is contained in:
Justine Tunney 2023-07-23 02:56:47 -07:00
parent 5c9e03e3e0
commit 1d4eb08fa1
No known key found for this signature in database
GPG key ID: BE714B4575D6E328
102 changed files with 678 additions and 331 deletions
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49
libc/calls/fcntl-nt.c
View file

@ -36,10 +36,13 @@
#include "libc/nt/runtime.h"
#include "libc/nt/struct/byhandlefileinformation.h"
#include "libc/nt/struct/overlapped.h"
#include "libc/nt/winsock.h"
#include "libc/sock/internal.h"
#include "libc/stdckdint.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/f.h"
#include "libc/sysv/consts/fd.h"
#include "libc/sysv/consts/fio.h"
#include "libc/sysv/consts/o.h"
#include "libc/sysv/errfuns.h"
#include "libc/thread/thread.h"
@ -307,21 +310,49 @@ static textwindows int sys_fcntl_nt_dupfd(int fd, int cmd, int start) {
return sys_dup_nt(fd, -1, (cmd == F_DUPFD_CLOEXEC ? O_CLOEXEC : 0), start);
}
static textwindows int sys_fcntl_nt_setfl(int fd, unsigned *flags, unsigned arg,
unsigned supported) {
unsigned old, neu, changed, other, allowed;
old = *flags & supported;
other = *flags & ~supported;
neu = arg & supported;
changed = old ^ neu;
// you may change the following access mode flags:
//
// - O_NONBLOCK make read() raise EAGAIN
// - O_NDELAY same thing as O_NONBLOCK
//
allowed = O_NONBLOCK;
if (changed & ~allowed) {
// the following access mode flags are supported, but it's currently
// not possible to change them on windows.
//
// - O_APPEND tried to support but failed
// - O_RANDOM use posix_fadvise() instead
// - O_SEQUENTIAL use posix_fadvise() instead
// - O_DIRECT possibly in future?
// - O_DSYNC possibly in future?
// - O_RSYNC possibly in future?
// - O_SYNC possibly in future?
//
return enotsup();
}
// 1. ignore flags that aren't access mode flags
// 2. return zero if nothing's changed
*flags = other | neu;
return 0;
}
textwindows int sys_fcntl_nt(int fd, int cmd, uintptr_t arg) {
int rc;
uint32_t flags;
int access_mode_flags = O_ACCMODE | O_APPEND | O_ASYNC | O_DIRECT |
O_NOATIME | O_NONBLOCK | O_RANDOM | O_SEQUENTIAL;
if (__isfdkind(fd, kFdFile) || __isfdkind(fd, kFdSocket)) {
if (cmd == F_GETFL) {
rc = g_fds.p[fd].flags &
(O_ACCMODE | O_APPEND | O_ASYNC | O_DIRECT | O_NOATIME | O_NONBLOCK |
O_RANDOM | O_SEQUENTIAL);
rc = g_fds.p[fd].flags & access_mode_flags;
} else if (cmd == F_SETFL) {
// O_APPEND doesn't appear to be tunable at cursory glance
// O_NONBLOCK might require we start doing all i/o in threads
// O_DSYNC / O_RSYNC / O_SYNC maybe if we fsync() everything
// O_DIRECT | O_RANDOM | O_SEQUENTIAL | O_NDELAY possible but
// not worth it.
rc = enosys();
rc = sys_fcntl_nt_setfl(fd, &g_fds.p[fd].flags, arg, access_mode_flags);
} else if (cmd == F_GETFD) {
if (g_fds.p[fd].flags & O_CLOEXEC) {
rc = FD_CLOEXEC;

8
libc/calls/fixupnewfd.c
View file

@ -26,9 +26,15 @@
// Applies file descriptor fixups on XNU or old Linux.
// See __fixupnewsockfd() for socket file descriptors.
int __fixupnewfd(int fd, int flags) {
int file_mode;
if (fd != -1) {
if (flags & O_CLOEXEC) {
_npassert(!__sys_fcntl(fd, F_SETFD, FD_CLOEXEC));
_unassert((file_mode = __sys_fcntl(fd, F_GETFD)) != -1);
_unassert(!__sys_fcntl(fd, F_SETFD, file_mode | FD_CLOEXEC));
}
if (flags & O_NONBLOCK) {
_unassert((file_mode = __sys_fcntl(fd, F_GETFL)) != -1);
_unassert(!__sys_fcntl(fd, F_SETFL, file_mode | O_NONBLOCK));
}
}
return fd;

2
libc/calls/getdomainname.c
View file

@ -76,6 +76,6 @@ int getdomainname(char *name, size_t len) {
if (!rc && len && !strcmp(name, "(none)")) {
name[0] = 0;
}
STRACE("getdomainname([%#.*s], %'zu) → %d% m", len, name, len, rc);
STRACE("getdomainname([%#.*s], %'zu) → %d% m", (int)len, name, len, rc);
return rc;
}

2
libc/calls/gethostname.c
View file

@ -71,6 +71,6 @@ int gethostname(char *name, size_t len) {
} else {
rc = enosys();
}
STRACE("gethostname([%#.*s], %'zu) → %d% m", len, name, len, rc);
STRACE("gethostname([%#.*s], %'zu) → %d% m", (int)len, name, len, rc);
return rc;
}

46
libc/calls/ioctl.c
View file

@ -558,34 +558,6 @@ static int ioctl_siocgifflags(int fd, void *arg) {
}
}
/**
* Sets "close on exec" on file descriptor the fast way.
*
* @see ioctl(fd, FIOCLEX, 0) dispatches here
*/
static int ioctl_fioclex(int fd, int req) {
int rc;
if (fd >= 0) {
if (IsWindows() || (fd < g_fds.n && g_fds.p[fd].kind == kFdZip)) {
if (__isfdopen(fd)) {
if (req == FIOCLEX) {
g_fds.p[fd].flags |= O_CLOEXEC;
} else {
g_fds.p[fd].flags &= ~O_CLOEXEC;
}
rc = 0;
} else {
rc = ebadf();
}
} else {
rc = sys_ioctl(fd, req);
}
} else {
rc = einval();
}
return rc;
}
/**
* Performs special i/o operation on file descriptor.
*
@ -618,17 +590,6 @@ static int ioctl_fioclex(int fd, int req) {
* - `TIOCNXCL` to give up exclusive mode on terminal. Only
* available on UNIX.
*
* - `FIOCLEX` sets the `O_CLOEXEC` state (no arg) noting that this
* polyfill may be removed in the future, and code should migrate
* to the equivalent fcntl() api.
*
* - `FIONBIO` sets the `O_NONBLOCK` state (arg is `int *enabled`)
* which is supported on Windows for sockets.
*
* - `FIONCLEX` clears the `O_CLOEXEC` state (no arg) noting that
* this polyfill may be removed in the future, and code should
* migrate to the equivalent fcntl() api.
*
* - `SIOCGIFCONF` takes an struct ifconf object of a given size,
* whose arg is `struct ifconf *`. It implements the Linux style
* and modifies the following:
@ -647,6 +608,9 @@ static int ioctl_fioclex(int fd, int req) {
* network broadcast addr. This data structure should be obtained
* by calling `SIOCGIFCONF`.
*
* - `FIONBIO` isn't polyfilled; use `fcntl(F_SETFL, O_NONBLOCK)`
* - `FIOCLEX` isn't polyfilled; use `fcntl(F_SETFD, FD_CLOEXEC)`
* - `FIONCLEX` isn't polyfilled; use `fcntl(F_SETFD, 0)`
* - `TCGETS` isn't polyfilled; use tcgetattr()
* - `TCSETS` isn't polyfilled; use tcsetattr()
* - `TCSETSW` isn't polyfilled; use tcsetattr()
@ -673,10 +637,6 @@ int ioctl(int fd, unsigned long request, ...) {
va_end(va);
if (request == FIONBIO) {
rc = ioctl_default(fd, request, arg);
} else if (request == FIOCLEX) {
rc = ioctl_fioclex(fd, request);
} else if (request == FIONCLEX) {
rc = ioctl_fioclex(fd, request);
} else if (request == TIOCGWINSZ) {
rc = tcgetwinsize(fd, arg);
} else if (request == TIOCSWINSZ) {

4
libc/calls/read-nt.c
View file

@ -33,6 +33,7 @@
#include "libc/nt/runtime.h"
#include "libc/nt/struct/overlapped.h"
#include "libc/nt/synchronization.h"
#include "libc/sysv/consts/o.h"
#include "libc/sysv/errfuns.h"
static textwindows ssize_t sys_read_nt_impl(struct Fd *fd, void *data,
@ -51,6 +52,9 @@ static textwindows ssize_t sys_read_nt_impl(struct Fd *fd, void *data,
if (SleepEx(__SIG_POLLING_INTERVAL_MS, true) == kNtWaitIoCompletion) {
POLLTRACE("IOCP EINTR");
}
if (fd->flags & O_NONBLOCK) {
return eagain();
}
if (_check_interrupts(true, g_fds.p)) {
POLLTRACE("sys_read_nt interrupted");
return -1;

2
libc/calls/readlinkat.c
View file

@ -56,6 +56,6 @@ ssize_t readlinkat(int dirfd, const char *path, char *buf, size_t bufsiz) {
bytes = sys_readlinkat_nt(dirfd, path, buf, bufsiz);
}
STRACE("readlinkat(%s, %#s, [%#.*s]) → %d% m", DescribeDirfd(dirfd), path,
MAX(0, bytes), buf, bytes);
(int)MAX(0, bytes), buf, bytes);
return bytes;
}

1
libc/calls/wincrash.c
View file

@ -42,6 +42,7 @@ unsigned __wincrash(struct NtExceptionPointers *ep) {
ucontext_t ctx;
struct CosmoTib *tib;
static bool noreentry;
noreentry = true;
if ((tib = __tls_enabled ? __get_tls_privileged() : 0)) {
if (~tib->tib_flags & TIB_FLAG_WINCRASHING) {

29
libc/calls/winsockerr.c
View file

@ -1,29 +0,0 @@
/*-*- 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/errno.h"
#include "libc/nt/winsock.h"
#include "libc/sock/internal.h"
/**
* Error return path for winsock wrappers.
*/
textwindows int64_t __winsockerr(void) {
errno = __dos2errno(WSAGetLastError());
return -1;
}