static int _losetup (
const char *loop, // Loop device
const char *file, // Target file (or block device)
int fatal
) {
int r, loopfd = -1, filefd = -1, mode;
r = filefd = open(file, mode = O_RDWR);
if (r < 0) {
r = filefd = open(file, mode = O_RDONLY);
if (r < 0) { if (fatal) _fatal("cannot open %s", file); goto exit; }
}
r = loopfd = open(loop, mode);
if (r < 0) {
r = loopfd = open(loop, mode = O_RDONLY);
if (r < 0) { if (fatal) _fatal("cannot open %s", loop); goto exit; }
}
r = losetup(loopfd, filefd, file);
if (r < 0 && fatal) _fatal("cannot setup loop device %s", loop);
exit:
close(loopfd);
close(filefd);
return r;
}
static int loop_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
{
int ret;
switch (cmd)
{
/* Command: LOOPIOC_SETUP
* Description: Setup the loop device
* Argument: A pointer to a read-only instance of struct losetup_s.
* Dependencies: The loop device must be enabled (CONFIG_DEV_LOOP=y)
*/
case LOOPIOC_SETUP:
{
FAR struct losetup_s *setup = (FAR struct losetup_s *)((uintptr_t)arg);
if (setup == NULL)
{
ret = -EINVAL;
}
else
{
ret = losetup(setup->devname, setup->filename, setup->sectsize,
setup->offset, setup->readonly);
}
}
break;
/* Command: LOOPIOC_TEARDOWN
* Description: Teardown a loop device previously setup vis LOOPIOC_SETUP
* Argument: A read-able pointer to the path of the device to be
* torn down
* Dependencies: The loop device must be enabled (CONFIG_DEV_LOOP=y)
*/
case LOOPIOC_TEARDOWN:
{
FAR const char *devname = (FAR const char *)((uintptr_t)arg);
if (devname == NULL)
{
ret = -EINVAL;
}
else
{
ret = loteardown(devname);
}
}
break;
default:
ret = -ENOTTY;
break;
}
return ret;
}
int cmd_losetup(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv)
{
char *loopdev = NULL;
char *filepath = NULL;
bool teardown = false;
bool readonly = false;
off_t offset = 0;
bool badarg = false;
int ret = ERROR;
int option;
/* Get the losetup options: Two forms are supported:
*
* losetup -d <loop-device>
* losetup [-o <offset>] [-r] <loop-device> <filename>
*
* NOTE that the -o and -r options are accepted with the -d option, but
* will be ignored.
*/
while ((option = getopt(argc, argv, "d:o:r")) != ERROR)
{
switch (option)
{
case 'd':
loopdev = nsh_getfullpath(vtbl, optarg);
teardown = true;
break;
case 'o':
offset = atoi(optarg);
break;
case 'r':
readonly = true;
break;
case '?':
default:
nsh_output(vtbl, g_fmtarginvalid, argv[0]);
badarg = true;
break;
}
}
/* If a bad argument was encountered, then return without processing the command */
if (badarg)
{
goto errout_with_paths;
}
/* If this is not a tear down operation, then additional command line
* parameters are required.
*/
if (!teardown)
{
/* There must be two arguments on the command line after the options */
if (optind + 1 < argc)
{
loopdev = nsh_getfullpath(vtbl, argv[optind]);
optind++;
filepath = nsh_getfullpath(vtbl, argv[optind]);
optind++;
}
else
{
nsh_output(vtbl, g_fmtargrequired, argv[0]);
goto errout_with_paths;
}
}
/* There should be nothing else on the command line */
if (optind < argc)
{
nsh_output(vtbl, g_fmttoomanyargs, argv[0]);
goto errout_with_paths;
}
/* Perform the teardown operation */
if (teardown)
{
/* Tear down the loop device. */
ret = loteardown(loopdev);
if (ret < 0)
{
nsh_output(vtbl, g_fmtcmdfailed, argv[0], "loteardown", NSH_ERRNO_OF(-ret));
goto errout_with_paths;
}
}
else
{
/* Set up the loop device */
ret = losetup(loopdev, filepath, 512, offset, readonly);
if (ret < 0)
{
nsh_output(vtbl, g_fmtcmdfailed, argv[0], "losetup", NSH_ERRNO_OF(-ret));
goto errout_with_paths;
}
}
/* Free memory */
errout_with_paths:
if (loopdev)
{
free(loopdev);
}
if (filepath)
{
free(filepath);
}
return ret;
}