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/* $OpenBSD: vioraw.c,v 1.8 2023/04/16 12:52:54 dv Exp $ */
/*
* Copyright (c) 2018 Ori Bernstein <ori@eigenstate.org>
*
* Permission to use, copy, modify, and 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 <sys/types.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include "virtio.h"
static ssize_t
raw_pread(void *file, char *buf, size_t len, off_t off)
{
return pread(*(int *)file, buf, len, off);
}
static ssize_t
raw_pwrite(void *file, char *buf, size_t len, off_t off)
{
return pwrite(*(int *)file, buf, len, off);
}
static void
raw_close(void *file, int stayopen)
{
if (!stayopen)
close(*(int *)file);
free(file);
}
/*
* Initializes a raw disk image backing file from an fd. Stores the
* number of bytes in *szp, returning -1 for error, 0 for success.
*/
int
virtio_raw_init(struct virtio_backing *file, off_t *szp, int *fd, size_t nfd)
{
off_t sz;
int *fdp;
if (nfd != 1)
return (-1);
sz = lseek(fd[0], 0, SEEK_END);
if (sz == -1)
return (-1);
fdp = malloc(sizeof(int));
if (!fdp)
return (-1);
*fdp = fd[0];
file->p = fdp;
file->pread = raw_pread;
file->pwrite = raw_pwrite;
file->close = raw_close;
*szp = sz;
return (0);
}
/*
* virtio_raw_create
*
* Create an empty imagefile with the specified path and size.
*
* Parameters:
* imgfile_path: path to the image file to create
* imgsize : size of the image file to create (in bytes)
*
* Return:
* EEXIST: The requested image file already exists
* 0 : Image file successfully created
* Exxxx : Various other Exxxx errno codes due to other I/O errors
*/
int
virtio_raw_create(const char *imgfile_path, uint64_t imgsize)
{
int fd, ret;
/* Refuse to overwrite an existing image */
fd = open(imgfile_path, O_RDWR | O_CREAT | O_TRUNC | O_EXCL,
S_IRUSR | S_IWUSR);
if (fd == -1)
return (errno);
/* Extend to desired size */
if (ftruncate(fd, (off_t)imgsize) == -1) {
ret = errno;
close(fd);
unlink(imgfile_path);
return (ret);
}
ret = close(fd);
return (ret);
}
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