/*
* vfs_get_root - Given a device name (stdin, stdout, etc.), hand
* back an appropriate inode.
*/
int
vfs_get_root(const char *devname, struct inode **node_store) {
assert(devname != NULL);
int ret = -E_NO_DEV;
if (!list_empty(&vdev_list)) {
lock_vdev_list();
{
list_entry_t *list = &vdev_list, *le = list;
while ((le = list_next(le)) != list) {
vfs_dev_t *vdev = le2vdev(le, vdev_link);
if (strcmp(devname, vdev->devname) == 0) {
struct inode *found = NULL;
if (vdev->fs != NULL) {
found = fsop_get_root(vdev->fs);
}
else if (!vdev->mountable) {
vop_ref_inc(vdev->devnode);
found = vdev->devnode;
}
if (found != NULL) {
ret = 0, *node_store = found;
}
else {
ret = -E_NA_DEV;
}
break;
}
}
}
unlock_vdev_list();
}
return ret;
}
/*
* Common code to pull the device name, if any, off the front of a
* path and choose the inode to begin the name lookup relative to.
*/
static int
get_device(char *path, char **subpath, struct inode **node_store) {
int i, slash = -1, colon = -1;
/*
* Locate the first colon or slash.
*/
for (i = 0; path[i] != '\0'; i ++) {
if (path[i] == ':') { colon = i; break; }
if (path[i] == '/') { slash = i; break; }
}
if (colon < 0 && slash != 0) {
/* *
* No colon before a slash, so no device name specified, and the slash isn't leading
* or is also absent, so this is a relative path or just a bare filename. Start from
* the current directory, and use the whole thing as the subpath.
* */
*subpath = path;
return vfs_get_curdir(node_store);
}
if (colon > 0) {
/* device:path - get root of device's filesystem */
path[colon] = '\0';
/* device:/path - skip slash, treat as device:path */
while (path[++ colon] == '/');
*subpath = path + colon;
return vfs_get_root(path, node_store);
}
/* *
* we have either /path or :path
* /path is a path relative to the root of the "boot filesystem"
* :path is a path relative to the root of the current filesystem
* */
int ret;
if (*path == '/') {
if ((ret = vfs_get_bootfs(node_store)) != 0) {
return ret;
}
}
else {
assert(*path == ':');
struct inode *node;
if ((ret = vfs_get_curdir(&node)) != 0) {
return ret;
}
/* The current directory may not be a device, so it must have a fs. */
assert(node->in_fs != NULL);
*node_store = fsop_get_root(node->in_fs);
vop_ref_dec(node);
}
/* ///... or :/... */
while (*(++ path) == '/');
*subpath = path;
return 0;
}
/*
* Given a device name (lhd0, emu0, somevolname, null, etc.), hand
* back an appropriate inode.
*/
int
vfs_get_root(const char *devname, struct inode **node_store) {
assert(devname != NULL);
int ret = -E_NO_DEV;
if (!list_empty(&vdev_list)) {
lock_vdev_list();
{
list_entry_t *list = &vdev_list, *le = list;
while ((le = list_next(le)) != list) {
vfs_dev_t *vdev = le2vdev(le, vdev_link);
if (strcmp(devname, vdev->devname) == 0) {
struct inode *found = NULL;
/*
* If this device has a mounted filesystem, and
* DEVNAME names either the filesystem or the device,
* return the root of the filesystem.
*
* If it has no mounted filesystem, it's mountable,
* and DEVNAME names the device, return -E_NA_DEV.
*/
if (vdev->fs != NULL) {
found = fsop_get_root(vdev->fs);
}
else if (!vdev->mountable) {
vop_ref_inc(vdev->devnode);
found = vdev->devnode;
}
if (found != NULL) {
/*
* If DEVNAME names the device, and we get here, it
* must have no fs and not be mountable. In this case,
* we return the inode of device itself--node_store.
*/
ret = 0, *node_store = found;
}
else {
/*
* If we got here, the device specified by devname doesn't exist.
*/
ret = -E_NA_DEV;
}
break;
}
/*
* If none of the above tests matched, we didn't name
* any of the names of this device, so go on to the
* next one.
*/
}
}
unlock_vdev_list();
}
return ret;
}