mirror of
https://github.com/jart/cosmopolitan.git
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b8a6a989c0
This change greatly reduces the number of modules that need to be compiled. The only issue right now is that sometimes when viewing symbol table entries, the aliased symbol is chosen.
91 lines
4.3 KiB
C
91 lines
4.3 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/calls/calls.h"
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#include "libc/calls/cp.internal.h"
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#include "libc/calls/internal.h"
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#include "libc/calls/syscall-nt.internal.h"
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#include "libc/calls/syscall-sysv.internal.h"
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#include "libc/dce.h"
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#include "libc/errno.h"
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#include "libc/intrin/strace.internal.h"
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#include "libc/sysv/errfuns.h"
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/**
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* Changes size of open file.
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*
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* If the file size is increased, the extended area shall appear as if
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* it were zero-filled. If your file size is decreased, the extra data
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* shall be lost.
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*
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* This function never changes the file position. This is true even if
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* ftruncate() causes the position to become beyond the end of file in
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* which case, the rules described in the lseek() documentation apply.
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*
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* Some operating systems implement an optimization, where `length` is
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* treated as a logical size and the requested physical space won't be
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* allocated until non-zero values get written into it. Our tests show
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* this happens on Linux (usually with 4096 byte granularity), FreeBSD
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* (which favors 512-byte granularity), and MacOS (prefers 4096 bytes)
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* however Windows, OpenBSD, and NetBSD always reserve physical space.
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* This may be inspected using fstat() and consulting stat::st_blocks.
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*
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* @param fd must be open for writing
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* @param length may be greater than current current file size
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* @return 0 on success, or -1 w/ errno
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* @raise EINVAL if `length` is negative
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* @raise EINTR if signal was delivered instead
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* @raise ECANCELED if thread was cancelled in masked mode
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* @raise EIO if a low-level i/o error happened
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* @raise EFBIG or EINVAL if `length` is too huge
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* @raise ENOTSUP if `fd` is a zip file descriptor
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* @raise EBADF if `fd` isn't an open file descriptor
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* @raise EINVAL if `fd` is a non-file, e.g. pipe, socket
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* @raise EINVAL if `fd` wasn't opened in a writeable mode
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* @raise ENOSYS on bare metal
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* @cancellationpoint
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* @asyncsignalsafe
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* @threadsafe
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*/
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int ftruncate(int fd, int64_t length) {
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int rc;
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BEGIN_CANCELLATION_POINT;
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if (fd < 0) {
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rc = ebadf();
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} else if (__isfdkind(fd, kFdZip)) {
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rc = enotsup();
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} else if (IsMetal()) {
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rc = enosys();
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} else if (!IsWindows()) {
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rc = sys_ftruncate(fd, length, length);
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if (IsNetbsd() && rc == -1 && errno == ENOSPC) {
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errno = EFBIG; // POSIX doesn't specify ENOSPC for ftruncate()
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}
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} else if (__isfdopen(fd)) {
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rc = sys_ftruncate_nt(g_fds.p[fd].handle, length);
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} else {
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rc = ebadf();
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}
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END_CANCELLATION_POINT;
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STRACE("ftruncate(%d, %'ld) → %d% m", fd, length, rc);
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return rc;
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}
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__strong_reference(ftruncate, ftruncate64);
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