Rewrite special file handling on Windows

This change gets GNU grep working. What caused it to not work, is it
wouldn't write to an output file descriptor when its dev/ino equaled
/dev/null's. So now we invent special dev/ino values for these files
This commit is contained in:
Justine Tunney 2023-10-14 01:06:00 -07:00
parent aca2261cda
commit 2db2f40a98
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53 changed files with 485 additions and 299 deletions

71
libc/calls/setfl.c Normal file
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/*-*- 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 2023 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/calls/internal.h"
#include "libc/calls/struct/fd.internal.h"
#include "libc/calls/syscall_support-nt.internal.h"
#include "libc/nt/createfile.h"
#include "libc/nt/enum/fileflagandattributes.h"
#include "libc/nt/files.h"
#include "libc/nt/runtime.h"
#include "libc/sysv/consts/o.h"
textwindows int sys_fcntl_nt_setfl(int fd, unsigned flags) {
// you may change the following:
//
// - O_NONBLOCK make read() raise EAGAIN
// - O_APPEND for toggling append mode
// - O_RANDOM alt. for posix_fadvise()
// - O_SEQUENTIAL alt. for posix_fadvise()
// - O_DIRECT works but haven't tested
//
// the other bits are ignored.
unsigned allowed = O_APPEND | O_SEQUENTIAL | O_RANDOM | O_DIRECT | O_NONBLOCK;
unsigned needreo = O_APPEND | O_SEQUENTIAL | O_RANDOM | O_DIRECT;
unsigned newflag = (g_fds.p[fd].flags & ~allowed) | (flags & allowed);
if (g_fds.p[fd].kind == kFdFile &&
((g_fds.p[fd].flags & needreo) ^ (flags & needreo))) {
unsigned perm, share, attr;
if (GetNtOpenFlags(newflag, g_fds.p[fd].mode, &perm, &share, 0, &attr) ==
-1) {
return -1;
}
// MSDN says only these are allowed, otherwise it returns EINVAL.
attr &= kNtFileFlagBackupSemantics | kNtFileFlagDeleteOnClose |
kNtFileFlagNoBuffering | kNtFileFlagOpenNoRecall |
kNtFileFlagOpenReparsePoint | kNtFileFlagOverlapped |
kNtFileFlagPosixSemantics | kNtFileFlagRandomAccess |
kNtFileFlagSequentialScan | kNtFileFlagWriteThrough;
intptr_t hand;
if ((hand = ReOpenFile(g_fds.p[fd].handle, perm, share, attr)) != -1) {
if (hand != g_fds.p[fd].handle) {
CloseHandle(g_fds.p[fd].handle);
g_fds.p[fd].handle = hand;
}
} else {
return __winerr();
}
}
// 1. ignore flags that aren't access mode flags
// 2. return zero if nothing's changed
g_fds.p[fd].flags = newflag;
return 0;
}