cosmopolitan/libc/calls/splice.c

73 lines
3.8 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/calls/calls.h"
#include "libc/calls/internal.h"
#include "libc/dce.h"
#include "libc/errno.h"
#include "libc/sysv/errfuns.h"
static ssize_t splicer(int infd, int64_t *inoffset, int outfd,
int64_t *outoffset, size_t uptobytes, uint32_t flags,
int64_t impl(int infd, int64_t *inoffset, int outfd,
int64_t *outoffset, size_t uptobytes,
uint32_t flags)) {
int olderr;
ssize_t transferred;
if (!uptobytes || flags == -1) return einval();
if (IsModeDbg() && uptobytes > 1) uptobytes >>= 1;
olderr = errno;
if ((transferred =
impl(infd, inoffset, outfd, outoffset, uptobytes, flags)) == -1 &&
errno == ENOSYS) {
errno = olderr;
transferred = copyfd(infd, inoffset, outfd, outoffset, uptobytes, flags);
}
return transferred;
}
/**
* Transfers data to/from pipe.
*
* @param flags can have SPLICE_F_{MOVE,NONBLOCK,MORE,GIFT}
* @return number of bytes transferred, 0 on input end, or -1 w/ errno
* @see copy_file_range() for file ↔ file
* @see sendfile() for seekable → socket
*/
ssize_t splice(int infd, int64_t *inopt_out_inoffset, int outfd,
int64_t *inopt_out_outoffset, size_t uptobytes, uint32_t flags) {
return splicer(infd, inopt_out_inoffset, outfd, inopt_out_outoffset,
uptobytes, flags, splice$sysv);
}
/**
* Transfers data between files.
*
* @param outfd should be a writable file, but not O_APPEND
* @param flags is reserved for future use
* @return number of bytes actually copied, or -1 w/ errno
* @see sendfile() for seekable → socket
* @see splice() for fd ↔ pipe
*/
ssize_t copy_file_range(int infd, int64_t *inopt_out_inoffset, int outfd,
int64_t *inopt_out_outoffset, size_t uptobytes,
uint32_t flags) {
return splicer(infd, inopt_out_inoffset, outfd, inopt_out_outoffset,
uptobytes, flags, copy_file_range$sysv);
}