This is a maintenance fork
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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 2020 Justine Alexandra Roberts Tunney │
│ │
│ This program is free software; you can redistribute it and/or modify │
│ it under the terms of the GNU General Public License as published by │
│ the Free Software Foundation; version 2 of the License. │
│ │
│ This program is distributed in the hope that it will be useful, but │
│ WITHOUT ANY WARRANTY; without even the implied warranty of │
│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
│ General Public License for more details. │
│ │
│ You should have received a copy of the GNU General Public License │
│ along with this program; if not, write to the Free Software │
│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
│ 02110-1301 USA │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/assert.h"
#include "libc/bits/bits.h"
#include "libc/bits/safemacros.h"
#include "libc/calls/calls.h"
#include "libc/calls/internal.h"
#include "libc/errno.h"
#include "libc/sysv/errfuns.h"
/**
* Copies data between file descriptors the slow way.
*
* @return -1 on error/interrupt, 0 on eof, or [1..uptobytes] on success
* @see copy_file_range() for file ↔ file
* @see sendfile() for seekable → socket
* @see splice() for fd ↔ pipe
*/
ssize_t copyfd(int infd, int64_t *inopt_out_inoffset, int to_fd,
int64_t *inopt_out_outoffset, size_t uptobytes, uint32_t flags) {
size_t i;
int64_t offset;
ssize_t got, wrote;
static unsigned char buf[1024 * 64];
/* unsigned char buf[1024 * 3]; */
uptobytes = min(sizeof(buf), uptobytes);
if (inopt_out_inoffset) {
got = pread(infd, buf, uptobytes, *inopt_out_inoffset);
} else {
got = read(infd, buf, uptobytes);
}
if (got == -1) return -1;
offset = inopt_out_outoffset ? *inopt_out_outoffset : -1;
for (i = 0; i < got; i += wrote) {
tryagain:
if (inopt_out_outoffset) {
wrote = pwrite(to_fd, buf, got - i, offset + i);
} else {
wrote = write(to_fd, buf, got - i);
}
if (wrote != -1) continue;
if (errno == EINTR) {
if (inopt_out_inoffset != NULL) {
return -1;
}
goto tryagain;
}
if (errno == EWOULDBLOCK) {
assert(inopt_out_inoffset != NULL); /* or caller is nuts */
}
return -1;
}
if (inopt_out_inoffset) *inopt_out_inoffset += got;
if (inopt_out_outoffset) *inopt_out_outoffset += got;
return got;
}