fsw_status_t fsw_dnode_create_with_tree(struct fsw_dnode *parent_dno, fsw_u64 tree_id, fsw_u64 dnode_id, int type,
struct fsw_string *name, struct fsw_dnode **dno_out)
{
fsw_status_t status;
struct fsw_volume *vol = parent_dno->vol;
struct fsw_dnode *dno;
// check if we already have a dnode with the same id
for (dno = vol->dnode_head; dno; dno = dno->next) {
if (dno->dnode_id == dnode_id && dno->tree_id == tree_id) {
fsw_dnode_retain(dno);
*dno_out = dno;
return FSW_SUCCESS;
}
}
// allocate memory for the structure
status = fsw_alloc_zero(vol->fstype_table->dnode_struct_size, (void **)&dno);
if (status)
return status;
// fill the structure
dno->vol = vol;
dno->parent = parent_dno;
fsw_dnode_retain(dno->parent);
dno->tree_id = tree_id;
dno->dnode_id = dnode_id;
dno->type = type;
dno->refcount = 1;
status = fsw_strdup_coerce(&dno->name, vol->host_table->native_string_type, name);
if (status) {
fsw_free(dno);
return status;
}
fsw_dnode_register(vol, dno);
*dno_out = dno;
return FSW_SUCCESS;
}
fsw_status_t fsw_dnode_resolve(struct fsw_dnode *dno, struct fsw_dnode **target_dno_out)
{
fsw_status_t status;
struct fsw_string target_name;
struct fsw_dnode *target_dno;
/* Linux kernel max link count is 40 */
int link_count = 40;
fsw_dnode_retain(dno);
while (--link_count > 0) {
// get full information
status = fsw_dnode_fill(dno);
if (status)
goto errorexit;
if (dno->type != FSW_DNODE_TYPE_SYMLINK) {
// found a non-symlink target, return it
*target_dno_out = dno;
return FSW_SUCCESS;
}
if (dno->parent == NULL) { // safety measure, cannot happen in theory
status = FSW_NOT_FOUND;
goto errorexit;
}
// read the link's target
status = fsw_dnode_readlink(dno, &target_name);
if (status)
goto errorexit;
// resolve it
status = fsw_dnode_lookup_path(dno->parent, &target_name, '/', &target_dno);
fsw_strfree(&target_name);
if (status)
goto errorexit;
// target_dno becomes the new dno
fsw_dnode_release(dno);
dno = target_dno; // is already retained
}
if(link_count == 0)
status = FSW_NOT_FOUND;
errorexit:
fsw_dnode_release(dno);
return status;
}
fsw_status_t fsw_shandle_open(struct fsw_dnode *dno, struct fsw_shandle *shand)
{
fsw_status_t status;
struct fsw_volume *vol = dno->vol;
// read full dnode information into memory
status = vol->fstype_table->dnode_fill(vol, dno);
if (status)
return status;
// setup shandle
fsw_dnode_retain(dno);
shand->dnode = dno;
shand->pos = 0;
shand->extent.type = FSW_EXTENT_TYPE_INVALID;
return FSW_SUCCESS;
}
fsw_status_t fsw_dnode_lookup_path(struct fsw_dnode *dno,
struct fsw_string *lookup_path, char separator,
struct fsw_dnode **child_dno_out)
{
fsw_status_t status;
struct fsw_volume *vol = dno->vol;
struct fsw_dnode *child_dno = NULL;
struct fsw_string lookup_name;
struct fsw_string remaining_path;
int root_if_empty;
remaining_path = *lookup_path;
fsw_dnode_retain(dno);
// loop over the path
for (root_if_empty = 1; fsw_strlen(&remaining_path) > 0; root_if_empty = 0) {
// parse next path component
fsw_strsplit(&lookup_name, &remaining_path, separator);
FSW_MSG_DEBUG((FSW_MSGSTR("fsw_dnode_lookup_path: split into %d '%s' and %d '%s'\n"),
lookup_name.len, lookup_name.data,
remaining_path.len, remaining_path.data));
if (fsw_strlen(&lookup_name) == 0) { // empty path component
if (root_if_empty)
child_dno = vol->root;
else
child_dno = dno;
fsw_dnode_retain(child_dno);
} else {
// do an actual directory lookup
// ensure we have full information
status = fsw_dnode_fill(dno);
if (status)
goto errorexit;
// resolve symlink if necessary
if (dno->type == FSW_DNODE_TYPE_SYMLINK) {
status = fsw_dnode_resolve(dno, &child_dno);
if (status)
goto errorexit;
// symlink target becomes the new dno
fsw_dnode_release(dno);
dno = child_dno; // is already retained
child_dno = NULL;
// ensure we have full information
status = fsw_dnode_fill(dno);
if (status)
goto errorexit;
}
// make sure we operate on a directory
if (dno->type != FSW_DNODE_TYPE_DIR) {
return FSW_UNSUPPORTED;
goto errorexit;
}
// check special paths
if (fsw_streq_cstr(&lookup_name, ".")) { // self directory
child_dno = dno;
fsw_dnode_retain(child_dno);
} else if (fsw_streq_cstr(&lookup_name, "..")) { // parent directory
if (dno->parent == NULL) {
// We cannot go up from the root directory. Caution: Certain apps like the EFI shell
// rely on this behaviour!
status = FSW_NOT_FOUND;
goto errorexit;
}
child_dno = dno->parent;
fsw_dnode_retain(child_dno);
} else {
// do an actual lookup
status = vol->fstype_table->dir_lookup(vol, dno, &lookup_name, &child_dno);
if (status)
goto errorexit;
}
}
// child_dno becomes the new dno
fsw_dnode_release(dno);
dno = child_dno; // is already retained
child_dno = NULL;
FSW_MSG_DEBUG((FSW_MSGSTR("fsw_dnode_lookup_path: now at inode %d\n"), dno->dnode_id));
}
*child_dno_out = dno;
return FSW_SUCCESS;
errorexit:
FSW_MSG_DEBUG((FSW_MSGSTR("fsw_dnode_lookup_path: leaving with error %d\n"), status));
fsw_dnode_release(dno);
if (child_dno != NULL)
fsw_dnode_release(child_dno);
return status;
}
