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/*
* Copyright (C) 2020 - Vito Caputo - <vcaputo@pengaru.com>
*
* This program is free software: you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 3 as published
* by the Free Software Foundation.
*
* 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, see <http://www.gnu.org/licenses/>.
*/
#include <assert.h>
#include <fcntl.h>
#include <liburing.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <iou.h>
#include <thunk.h>
#include "readfile.h"
#include "op.h"
/* Implements iou-based file read into a supplied buffer.
*/
/* call user-supplied closure now that buf is populated */
THUNK_DEFINE_STATIC(read_done, iou_t *, iou, iou_op_t *, op, int, fd, char *, buf, size_t *, size, thunk_t *, closure)
{
assert(iou);
assert(op);
assert(closure);
if (op->result < 0)
return op->result;
(void) close(fd);
*size = op->result;
return thunk_end(thunk_dispatch(closure));
}
/* ask iou to read from the opened fd into buf */
THUNK_DEFINE_STATIC(open_done, iou_t *, iou, iou_op_t *, op, char *, buf, size_t *, size, thunk_t *, closure)
{
thunk_t *read_closure;
iou_op_t *read_op;
assert(iou);
assert(op);
if (op->result < 0)
return op->result;
read_op = iou_op_new(iou);
if (!read_op)
return -ENOMEM;
read_closure = THUNK(read_done(iou, read_op, op->result, buf, size, closure));
if (!read_closure)
return -ENOMEM;
io_uring_prep_read(read_op->sqe, op->result, buf, *size, 0);
op_queue(iou, read_op, read_closure);
return 0;
}
/* read a file into a buffer via iou, dispatching closure when complete */
/* size specifies the buf size, and will also get the length of what's read
* written to it upon completion.
*/
/* returns < 0 on error, 0 on successful queueing of operation */
THUNK_DEFINE(readfile, iou_t *, iou, const char *, path, char *, buf, size_t *, size, thunk_t *, closure)
{
iou_op_t *op;
op = iou_op_new(iou);
if (!op)
return -ENOMEM;
/* req iou to open path, passing the req to read its contents */
io_uring_prep_openat(op->sqe, 0, path, 0, O_RDONLY);
op_queue(iou, op, THUNK(open_done(iou, op, buf, size, closure)));
return 0;
}
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