// callback to be fed int vdev_load_all_at.
// builds up the children listing of vdevfs_scandirat_context.parent_dir.
// if we find a directory, open it and enqueue its file descriptor to dir_queue.
// return 0 on success
// return -ENOMEM on OOM
static int vdevfs_scandirat_context_callback( int dirfd, struct dirent* dent, void* cls ) {
struct vdevfs_scandirat_context* ctx = (struct vdevfs_scandirat_context*)cls;
int rc = 0;
int fd = 0;
struct stat sb;
struct fskit_entry* child;
char linkbuf[8193]; // for resolving an underlying symlink
char const* method_name; // for logging
char* joined_path = NULL;
// skip . and ..
if( strcmp( dent->d_name, "." ) == 0 || strcmp( dent->d_name, ".." ) == 0 ) {
return 0;
}
// learn more...
rc = fstatat( dirfd, dent->d_name, &sb, AT_SYMLINK_NOFOLLOW );
if( rc != 0 ) {
rc = -errno;
// mask errors; just log the serious ones
if( rc != -ENOENT && rc != -EACCES ) {
vdev_error("fstatat(%d, '%s') rc = %d\n", dirfd, dent->d_name, rc );
}
return 0;
}
// directory? get an fd to it if so, so we can keep scanning
if( S_ISDIR( sb.st_mode ) ) {
// try to get at it
fd = openat( dirfd, dent->d_name, O_RDONLY );
if( fd < 0 ) {
rc = -errno;
// mask errors; just log the serious ones
if( rc != -ENOENT && rc != -EACCES ) {
vdev_error("openat(%d, '%s') rc = %d\n", dirfd, dent->d_name, rc );
}
return 0;
}
// woo! save it
joined_path = vdev_fullpath( ctx->parent_path, dent->d_name, NULL );
if( joined_path == NULL ) {
close( fd );
return -ENOMEM;
}
try {
ctx->dir_paths->push( joined_path );
}
catch( bad_alloc& ba ) {
// OOM
free( joined_path );
return -ENOMEM;
}
try {
ctx->dir_queue->push( fd );
}
catch( bad_alloc& ba ) {
// OOM
close( fd );
return -ENOMEM;
}
}
// construct an inode for this entry
child = VDEV_CALLOC( struct fskit_entry, 1 );
if( child == NULL ) {
return -ENOMEM;
}
// regular file?
if( S_ISREG( sb.st_mode ) ) {
method_name = "fskit_entry_init_file";
rc = fskit_entry_init_file( child, sb.st_ino, dent->d_name, sb.st_uid, sb.st_gid, sb.st_mode & 0777 );
}
// directory?
else if( S_ISDIR( sb.st_mode ) ) {
method_name = "fskit_entry_init_dir";
rc = fskit_entry_init_dir( child, ctx->parent_dir, sb.st_ino, dent->d_name, sb.st_uid, sb.st_gid, sb.st_mode & 0777 );
}
// named pipe?
else if( S_ISFIFO( sb.st_mode ) ) {
method_name = "fskit_entry_init_fifo";
rc = fskit_entry_init_fifo( child, sb.st_ino, dent->d_name, sb.st_uid, sb.st_gid, sb.st_mode & 0777 );
}
// unix domain socket?
else if( S_ISSOCK( sb.st_mode ) ) {
method_name = "fskit_entry_init_sock";
rc = fskit_entry_init_sock( child, sb.st_ino, dent->d_name, sb.st_uid, sb.st_gid, sb.st_mode & 0777 );
}
// character device?
else if( S_ISCHR( sb.st_mode ) ) {
method_name = "fskit_entry_init_chr";
rc = fskit_entry_init_chr( child, sb.st_ino, dent->d_name, sb.st_uid, sb.st_gid, sb.st_mode, sb.st_rdev );
}
// block device?
else if( S_ISBLK( sb.st_mode ) ) {
method_name = "fskit_entry_init_blk";
rc = fskit_entry_init_blk( child, sb.st_ino, dent->d_name, sb.st_uid, sb.st_gid, sb.st_mode, sb.st_rdev );
}
// symbolic link?
else if( S_ISLNK( sb.st_mode ) ) {
// read the link first...
memset( linkbuf, 0, 8193 );
rc = readlinkat( dirfd, dent->d_name, linkbuf, 8192 );
if( rc < 0 ) {
rc = -errno;
// mask error, but log serious ones. this link will not appear in the listing
if( rc != -ENOENT && rc != -EACCES ) {
vdev_error("readlinkat(%d, '%s') rc = %d\n", dirfd, dent->d_name, rc );
}
free( child );
child = NULL;
return 0;
}
method_name = "fskit_entry_init_symlink";
rc = fskit_entry_init_symlink( child, sb.st_ino, dent->d_name, linkbuf );
}
// success?
if( rc != 0 ) {
vdev_error("%s( on %d, '%s' ) rc = %d\n", method_name, dirfd, dent->d_name, rc );
free( child );
child = NULL;
return rc;
}
// insert into parent
rc = fskit_entry_attach_lowlevel( ctx->parent_dir, child );
if( rc != 0 ) {
// OOM
fskit_entry_destroy( ctx->core, child, false );
free( child );
child = NULL;
return rc;
}
// success!
return rc;
}
// low-level mkdir: create a child and insert it into the parent.
// parent must be a directory
// parent must be write-locked
// return -EEXIST if an entry with the given name (path_basename) already exists in parent.
// return -EIO if we couldn't allocate an inode
// return -ENOMEM if we couldn't allocate memory
static int fskit_mkdir_lowlevel( struct fskit_core* core, char const* path, struct fskit_entry* parent, char const* path_basename, mode_t mode, uint64_t user, uint64_t group, void* cls ) {
// resolve the child within the parent
struct fskit_entry* child = fskit_entry_set_find_name( parent->children, path_basename );
int err = 0;
void* app_dir_data = NULL;
if( child != NULL ) {
fskit_entry_wlock( child );
err = fskit_entry_try_garbage_collect( core, path, parent, child );
if( err >= 0 ) {
if( err == 0 ) {
// detached but not destroyed
fskit_entry_unlock( child );
}
// name is free
child = NULL;
}
else {
fskit_entry_unlock( child );
if( err == -EEXIST ) {
// still exists; can't be garbage-collected
return -EEXIST;
}
else {
// shouldn't happen
fskit_error("BUG: fskit_entry_try_garbage_collect(%s) rc = %d\n", path, err );
return -EIO;
}
}
}
if( child == NULL ) {
// create an fskit_entry and attach it
child = CALLOC_LIST( struct fskit_entry, 1 );
if( child == NULL ) {
return -ENOMEM;
}
// get an inode for this child
uint64_t child_inode = fskit_core_inode_alloc( core, parent, child );
if( child_inode == 0 ) {
// error in allocation
fskit_error("fskit_core_inode_alloc(%s) failed\n", path );
fskit_safe_free( child );
return -EIO;
}
// set up the directory
err = fskit_entry_init_dir( child, parent, child_inode, user, group, mode );
if( err != 0 ) {
fskit_error("fskit_entry_init_dir(%s) rc = %d\n", path, err );
fskit_safe_free( child );
return err;
}
// reference this directory, so it won't disappear during the user's route
child->open_count++;
// almost done. run the route callback for this path if needed
err = fskit_run_user_mkdir( core, path, parent, child, mode, cls, &app_dir_data );
child->open_count--;
if( err != 0 ) {
// user route failed
fskit_error("fskit_run_user_mkdir(%s) rc = %d\n", path, err );
fskit_entry_destroy( core, child, false );
fskit_safe_free( child );
}
else {
fskit_entry_set_user_data( child, app_dir_data );
// attach to parent
fskit_entry_attach_lowlevel( parent, child, path_basename );
}
}