cosmopolitan/libc/calls/dup-nt.c
Justine Tunney 3f49889841
Make important improvements
- Fix preadv() and pwritev() for old distros
- Introduce _npassert() and _unassert() macros
- Prove that file locks work properly on Windows
- Support fcntl(F_DUPFD_CLOEXEC) on more systems
2022-09-14 22:39:08 -07:00

97 lines
3.9 KiB
C

/*-*- 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/state.internal.h"
#include "libc/calls/syscall_support-nt.internal.h"
#include "libc/intrin/weaken.h"
#include "libc/nt/files.h"
#include "libc/nt/runtime.h"
#include "libc/sock/internal.h"
#include "libc/sysv/consts/o.h"
#include "libc/sysv/errfuns.h"
/**
* Implements dup(), dup2(), dup3(), and F_DUPFD for Windows.
*/
textwindows int sys_dup_nt(int oldfd, int newfd, int flags, int start) {
int64_t rc, proc, handle;
_unassert(oldfd >= 0);
_unassert(newfd >= -1);
_unassert(!(flags & ~O_CLOEXEC));
__fds_lock();
if (oldfd >= g_fds.n ||
(g_fds.p[oldfd].kind != kFdFile && g_fds.p[oldfd].kind != kFdSocket &&
g_fds.p[oldfd].kind != kFdConsole)) {
__fds_unlock();
return ebadf();
}
// allocate a new file descriptor
for (;;) {
if (newfd == -1) {
if ((newfd = __reservefd_unlocked(start)) == -1) {
__fds_unlock();
return -1;
}
break;
} else {
if (__ensurefds_unlocked(newfd) == -1) {
__fds_unlock();
return -1;
}
if (g_fds.p[newfd].kind) {
__fds_unlock();
close(newfd);
__fds_lock();
}
if (!g_fds.p[newfd].kind) {
g_fds.p[newfd].kind = kFdReserved;
break;
}
}
}
handle = g_fds.p[oldfd].handle;
proc = GetCurrentProcess();
if (DuplicateHandle(proc, handle, proc, &g_fds.p[newfd].handle, 0, true,
kNtDuplicateSameAccess)) {
g_fds.p[newfd].kind = g_fds.p[oldfd].kind;
g_fds.p[newfd].mode = g_fds.p[oldfd].mode;
g_fds.p[newfd].flags = g_fds.p[oldfd].flags & ~O_CLOEXEC;
if (flags & O_CLOEXEC) g_fds.p[newfd].flags |= O_CLOEXEC;
if (g_fds.p[oldfd].kind == kFdSocket && _weaken(_dupsockfd)) {
g_fds.p[newfd].extra =
(intptr_t)_weaken(_dupsockfd)((struct SockFd *)g_fds.p[oldfd].extra);
} else {
g_fds.p[newfd].extra = g_fds.p[oldfd].extra;
}
rc = newfd;
} else {
__releasefd_unlocked(newfd);
rc = __winerr();
}
__fds_unlock();
return rc;
}