cosmopolitan/libc/calls/closefrom.c
Jōshin e16a7d8f3b
flip et / noet in modelines
`et` means `expandtab`.

```sh
rg 'vi: .* :vi' -l -0 | \
  xargs -0 sed -i '' 's/vi: \(.*\) et\(.*\)  :vi/vi: \1 xoet\2:vi/'
rg 'vi: .*  :vi' -l -0 | \
  xargs -0 sed -i '' 's/vi: \(.*\)noet\(.*\):vi/vi: \1et\2  :vi/'
rg 'vi: .*  :vi' -l -0 | \
  xargs -0 sed -i '' 's/vi: \(.*\)xoet\(.*\):vi/vi: \1noet\2:vi/'
```
2023-12-07 22:17:11 -05:00

65 lines
3.1 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2022 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/blockcancel.internal.h"
#include "libc/calls/calls.h"
#include "libc/calls/syscall-sysv.internal.h"
#include "libc/dce.h"
#include "libc/errno.h"
#include "libc/intrin/strace.internal.h"
#include "libc/limits.h"
#include "libc/sysv/errfuns.h"
/**
* Closes extra file descriptors, e.g.
*
* if (closefrom(3))
* for (int i = 3; i < 256; ++i)
* close(i);
*
* @return 0 on success, or -1 w/ errno
* @raise EBADF if `first` is negative
* @raise ENOSYS if not Linux 5.9+, FreeBSD 8+, OpenBSD, or NetBSD
* @raise EBADF on OpenBSD if `first` is greater than highest fd
* @raise EINVAL if flags are bad or first is greater than last
* @raise EMFILE if a weird race condition happens on Linux
* @raise EINTR possibly on OpenBSD
* @raise ENOMEM on Linux maybe
*/
int closefrom(int first) {
int rc;
BLOCK_CANCELATION;
if (first < 0) {
// consistent with openbsd
// freebsd allows this but it's dangerous
// necessary on linux due to type signature
rc = ebadf();
} else if (IsFreebsd() || IsOpenbsd()) {
rc = sys_closefrom(first);
} else if (IsLinux()) {
rc = sys_close_range(first, 0xffffffffu, 0);
} else if (IsNetbsd()) {
rc = __sys_fcntl(first, 10 /*F_CLOSEM*/, first);
} else {
rc = enosys();
}
ALLOW_CANCELATION;
STRACE("closefrom(%d) → %d% m", first, rc);
return rc;
}