Updated: October 28, 2024 |
The last function we'll look at is the one that handles mount requests. Handling a mount request can be fairly tricky (there are lots of options), so we've just stuck with a simple version that does everything we need for the RAM disk.
When the RAM-disk resource manager starts up, there is no mounted RAM disk, so you must use the command-line mount command to mount one:
mount -Tramdisk /dev/ramdisk /ramdisk
The above command creates a RAM disk at the mount point /ramdisk.
The code is:
int cfs_c_mount (resmgr_context_t *ctp, io_mount_t *msg, RESMGR_HANDLE_T *handle, io_mount_extra_t *extra) { char *mnt_point; char *mnt_type; int ret; cfs_attr_t *cfs_attr; // 1) shortcuts mnt_point = msg -> connect.path; mnt_type = extra -> extra.srv.type; // 2) Verify that it is a mount request, not something else if (extra -> flags & (_MOUNT_ENUMERATE | _MOUNT_UNMOUNT | _MOUNT_REMOUNT)) { return (ENOTSUP); } // 3) decide if we should handle this request or not if (!mnt_type || strcmp (mnt_type, "ramdisk")) { return (ENOSYS); } // 4) create a new attributes structure and fill it if (!(cfs_attr = malloc (sizeof (*cfs_attr)))) { return (ENOMEM); } iofunc_attr_init (&cfs_attr -> attr, S_IFDIR | 0777, NULL, NULL); // 5) initializes extended attribute structure cfs_attr_init (cfs_attr); // set up the inode cfs_attr -> attr.inode = (ino_t) cfs_attr; // create "." and ".." cfs_a_mknod (cfs_attr, ".", S_IFDIR | 0755, NULL); cfs_a_mknod (cfs_attr, "..", S_IFDIR | 0755, NULL); // 6) attach the new pathname with the new value ret = resmgr_attach (dpp, &resmgr_attr, mnt_point, _FTYPE_ANY, _RESMGR_FLAG_DIR, &connect_func, &io_func, &cfs_attr -> attr); if (ret == -1) { free (cfs_attr); return (errno); } return (EOK); }
The code walkthrough is:
The inode needs to be unique for each device, so the easiest way of doing that is to give it the address of the attributes structure.