// SPDX-License-Identifier: GPL-2.0

#include "kublk.h"

void backing_file_tgt_deinit(struct ublk_dev *dev)
{
        int i;

        for (i = 1; i < dev->nr_fds; i++) {
                fsync(dev->fds[i]);
                close(dev->fds[i]);
        }
}

int backing_file_tgt_init(struct ublk_dev *dev, unsigned int nr_direct)
{
        int fd, i;

        ublk_assert(dev->nr_fds == 1);

        for (i = 0; i < dev->tgt.nr_backing_files; i++) {
                char *file = dev->tgt.backing_file[i];
                unsigned long bytes;
                struct stat st;

                ublk_dbg(UBLK_DBG_DEV, "%s: file %d: %s\n", __func__, i, file);

                fd = open(file, O_RDWR | (i < nr_direct ? O_DIRECT : 0));
                if (fd < 0) {
                        ublk_err("%s: backing file %s can't be opened: %s\n",
                                        __func__, file, strerror(errno));
                        return -EBADF;
                }

                if (fstat(fd, &st) < 0) {
                        close(fd);
                        return -EBADF;
                }

                if (S_ISREG(st.st_mode))
                        bytes = st.st_size;
                else if (S_ISBLK(st.st_mode)) {
                        if (ioctl(fd, BLKGETSIZE64, &bytes) != 0)
                                return -1;
                } else {
                        return -EINVAL;
                }

                dev->tgt.backing_file_size[i] = bytes;
                dev->fds[dev->nr_fds] = fd;
                dev->nr_fds += 1;
        }

        return 0;
}