Changeset 7313e7a in mainline for uspace/srv/vfs/vfs_mount.c

Timestamp:

2007-09-28T20:11:02Z (18 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

2c2e0c6

Parents:

0e0476ad

Message:

VFS work.
This is a checkpoint commit.
It introduces initial, still incomplete, code for VFS-side VFS_MOUNT request.

File:

• uspace/srv/vfs/vfs_mount.c (modified) (1 diff)

uspace/srv/vfs/vfs_mount.c

@@ -46 +46 @@
 #include "vfs.h"
 
-vfs_node_t *rootfs = NULL;
+vfs_node_t rootfs = { 0 };
+
+static int lookup_root(int fs_handle, int dev_handle, vfs_node_t *root)
+{
+        vfs_node_t altroot = {
+                .fs_handle = fs_handle,
+                .dev_handle = dev_handle,
+                /*
+                 * At this point, we don't know what is the index of the root
+                 * node. Finally, that's what this function is about.
+                 */
+        };
+
+        return vfs_lookup_internal("/", 1, root, &altroot);
+}
 
 void vfs_mount(ipc_callid_t rid, ipc_call_t *request)
 {
+        int dev_handle;
+
+        /*
+         * We expect the library to do the device-name to device-handle
+         * translation for us, thus the device handle will arrive as ARG1
+         * in the request.
+         */
+        dev_handle = IPC_GET_ARG1(*request);
+
+        /*
+         * For now, don't make use of ARG2 and ARG3, but they can be used to
+         * carry mount options in the future.
+         */
+
+        /*
+         * Now, we expect the client to send us data with the name of the file
+         * system and the path of the mountpoint.
+         */
+        ipc_callid_t callid;
+        ipc_call_t call;
+        size_t size;
+        if (!ipc_data_receive(&callid, &call, NULL, &size)) {
+                ipc_answer_fast(callid, EINVAL, 0, 0);
+                ipc_answer_fast(rid, EINVAL, 0, 0);
+                return;
+        }
+
+        /*
+         * There is no sense in receiving data that can't hold a single
+         * character of path. We won't accept data that exceed certain limits
+         * either.
+         */
+        if ((size < FS_NAME_MAXLEN + 1) ||
+            (size > FS_NAME_MAXLEN + MAX_PATH_LEN)) {
+                ipc_answer_fast(callid, EINVAL, 0, 0);
+                ipc_answer_fast(rid, EINVAL, 0, 0);
+                return;
+        }
+
+        /*
+         * Allocate buffer for the data being received.
+         */
+        uint8_t *buf;
+        buf = malloc(size);
+        if (!buf) {
+                ipc_answer_fast(callid, ENOMEM, 0, 0);
+                ipc_answer_fast(rid, ENOMEM, 0, 0);
+                return;
+        }
+
+        /*
+         * Deliver the data.
+         */
+        (void) ipc_data_deliver(callid, &call, buf, size);
+
+        char fs_name[FS_NAME_MAXLEN + 1];
+        memcpy(fs_name, buf, FS_NAME_MAXLEN);
+        fs_name[FS_NAME_MAXLEN] = '\0';
+
+        /*
+         * Check if we know a file system with the same name as is in fs_name.
+         * This will also give us its file system handle.
+         */
+        int fs_handle = fs_name_to_handle(fs_name, true);
+        if (!fs_handle) {
+                free(buf);
+                ipc_answer_fast(rid, ENOENT, 0, 0);
+                return;
+        }
+
+        /*
+         * Lookup the root node of the filesystem being mounted.
+         */
+        int rc;
+        vfs_node_t mounted_root;
+        rc = lookup_root(fs_handle, dev_handle, &mounted_root);
+        if (rc != EOK) {
+                free(buf);
+                ipc_answer_fast(rid, rc, 0, 0);
+                return;
+        }
+
+        /*
+         * Finally, we need to resolve the path to the mountpoint. 
+         */
+        vfs_node_t mp;
+        if (rootfs.fs_handle) {
+                /*
+                 * We already have the root FS.
+                 */
+                rc = vfs_lookup_internal((char *) (buf + FS_NAME_MAXLEN),
+                    size - FS_NAME_MAXLEN, &mp, NULL);
+                if (rc != EOK) {
+                        /*
+                         * The lookup failed for some reason.
+                         */
+                        free(buf);
+                        ipc_answer_fast(rid, rc, 0, 0);
+                        return;
+                }
+        } else {
+                /*
+                 * We still don't have the root file system mounted.
+                 */
+                if ((size - FS_NAME_MAXLEN == 1) &&
+                    (buf[FS_NAME_MAXLEN] == '/')) {
+                        /*
+                         * For this simple, but important case, we are done.
+                         */
+                        rootfs = mounted_root;
+                        free(buf);
+                        ipc_answer_fast(rid, EOK, 0, 0);
+                        return;
+                } else {
+                        /*
+                         * We can't resolve this without the root filesystem
+                         * being mounted first.
+                         */
+                        free(buf);
+                        ipc_answer_fast(rid, ENOENT, 0, 0);
+                        return;
+                }
+        }
+                
+        /*
+         * At this point, we have all necessary pieces: file system and device
+         * handles, and we know the mount point VFS node and also the root node
+         * of the file system being mounted.
+         */
+        
 }