WebSVN – HelenOS – Diff – /branches/dynload/uspace/srv/vfs/vfs_ops.c

 /*
  * Copyright (c) 2008 Jakub Jermar
  * All rights reserved.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
+ *
  * - Redistributions of source code must retain the above copyright
  *   notice, this list of conditions and the following disclaimer.
  * - Redistributions in binary form must reproduce the above copyright
  *   notice, this list of conditions and the following disclaimer in the
  *   documentation and/or other materials provided with the distribution.
  * - The name of the author may not be used to endorse or promote products
  *   derived from this software without specific prior written permission.
+ *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 /** @addtogroup fs
  * @{
  */
 /**
  * @file    vfs_ops.c
  * @brief   Operations that VFS offers to its clients.
  */
+#include "vfs.h"
 #include <ipc/ipc.h>
 #include <async.h>
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <bool.h>
 #include <futex.h>
 #include <rwlock.h>
 #include <libadt/list.h>
 #include <unistd.h>
 #include <ctype.h>
 #include <fcntl.h>
 #include <assert.h>
 #include <atomic.h>
-#include "vfs.h"
+#include <vfs/canonify.h>
 /* Forward declarations of static functions. */
 static int vfs_truncate_internal(int, int, unsigned long, size_t);
 /**
  * This rwlock prevents the race between a triplet-to-VFS-node resolution and a
  * concurrent VFS operation which modifies the file system namespace.
  */
 RWLOCK_INITIALIZE(namespace_rwlock);
 atomic_t rootfs_futex = FUTEX_INITIALIZER;
 vfs_triplet_t rootfs = {
     .fs_handle = 0,
     .dev_handle = 0,
     .index = 0,
 };
 static int lookup_root(int fs_handle, int dev_handle, vfs_lookup_res_t *result)
+{
     vfs_pair_t altroot = {
         .fs_handle = fs_handle,
         .dev_handle = dev_handle,
     };
     return vfs_lookup_internal("/", L_DIRECTORY, result, &altroot);
+}
 void vfs_mount(ipc_callid_t rid, ipc_call_t *request)
+{
     int dev_handle;
     vfs_node_t *mp_node = NULL;
     /*
      * 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.
      */
     ipc_callid_t callid;
     size_t size;
     /*
      * Now, we expect the client to send us data with the name of the file
      * system.
      */
     if (!ipc_data_write_receive(&callid, &size)) {
         ipc_answer_0(callid, EINVAL);
         ipc_answer_0(rid, EINVAL);
         return;
+    }
     /*
      * Don't receive more than is necessary for storing a full file system
      * name.
      */
     if (size < 1 || size > FS_NAME_MAXLEN) {
         ipc_answer_0(callid, EINVAL);
         ipc_answer_0(rid, EINVAL);
         return;
+    }
     /* Deliver the file system name. */
     char fs_name[FS_NAME_MAXLEN + 1];
     (void) ipc_data_write_finalize(callid, fs_name, size);
     fs_name[size] = '\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) {
         ipc_answer_0(rid, ENOENT);
         return;
+    }
     /* Now, we want the client to send us the mount point. */
     if (!ipc_data_write_receive(&callid, &size)) {
         ipc_answer_0(callid, EINVAL);
         ipc_answer_0(rid, EINVAL);
         return;
+    }
     /* Check whether size is reasonable wrt. the mount point. */
     if (size < 1 || size > MAX_PATH_LEN) {
         ipc_answer_0(callid, EINVAL);
         ipc_answer_0(rid, EINVAL);
         return;
+    }
     /* Allocate buffer for the mount point data being received. */
     uint8_t *buf;
     buf = malloc(size + 1);
     if (!buf) {
         ipc_answer_0(callid, ENOMEM);
         ipc_answer_0(rid, ENOMEM);
         return;
+    }
     /* Deliver the mount point. */
     (void) ipc_data_write_finalize(callid, buf, size);
     buf[size] = '\0';
     /*
      * Lookup the root node of the filesystem being mounted.
      * In this case, we don't need to take the namespace_futex as the root
      * node cannot be removed. However, we do take a reference to it so
      * that we can track how many times it has been mounted.
      */
     int rc;
     vfs_lookup_res_t mr_res;
     rc = lookup_root(fs_handle, dev_handle, &mr_res);
     if (rc != EOK) {
         free(buf);
         ipc_answer_0(rid, rc);
         return;
+    }
     vfs_node_t *mr_node = vfs_node_get(&mr_res);
     if (!mr_node) {
         free(buf);
         ipc_answer_0(rid, ENOMEM);
         return;
+    }
     /* Finally, we need to resolve the path to the mountpoint. */
     vfs_lookup_res_t mp_res;
     futex_down(&rootfs_futex);
     if (rootfs.fs_handle) {
         /* We already have the root FS. */
         rwlock_write_lock(&namespace_rwlock);
         rc = vfs_lookup_internal(buf, L_DIRECTORY, &mp_res, NULL);
         if (rc != EOK) {
             /* The lookup failed for some reason. */
             rwlock_write_unlock(&namespace_rwlock);
             futex_up(&rootfs_futex);
             vfs_node_put(mr_node);  /* failed -> drop reference */
             free(buf);
             ipc_answer_0(rid, rc);
             return;
+        }
         mp_node = vfs_node_get(&mp_res);
         if (!mp_node) {
             rwlock_write_unlock(&namespace_rwlock);
             futex_up(&rootfs_futex);
             vfs_node_put(mr_node);  /* failed -> drop reference */
             free(buf);
             ipc_answer_0(rid, ENOMEM);
             return;
+        }
         /*
          * Now we hold a reference to mp_node.
          * It will be dropped upon the corresponding VFS_UNMOUNT.
          * This prevents the mount point from being deleted.
          */
         rwlock_write_unlock(&namespace_rwlock);
     } else {
         /* We still don't have the root file system mounted. */
         if ((size == 1) && (buf[0] == '/')) {
             /* For this simple, but important case, we are done. */
             rootfs = mr_res.triplet;
             futex_up(&rootfs_futex);
             free(buf);
             ipc_answer_0(rid, EOK);
             return;
         } else {
             /*
              * We can't resolve this without the root filesystem
              * being mounted first.
              */
             futex_up(&rootfs_futex);
             free(buf);
             vfs_node_put(mr_node);  /* failed -> drop reference */
             ipc_answer_0(rid, ENOENT);
             return;
+        }
+    }
     futex_up(&rootfs_futex);
     free(buf);  /* The buffer is not needed anymore. */
     /*
      * 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.
      */
     int phone = vfs_grab_phone(mp_res.triplet.fs_handle);
     /* Later we can use ARG3 to pass mode/flags. */
     aid_t req1 = async_send_3(phone, VFS_MOUNT,
         (ipcarg_t) mp_res.triplet.dev_handle,
         (ipcarg_t) mp_res.triplet.index, 0, NULL);
     /* The second call uses the same method. */
     aid_t req2 = async_send_3(phone, VFS_MOUNT,
         (ipcarg_t) mr_res.triplet.fs_handle,
         (ipcarg_t) mr_res.triplet.dev_handle,
         (ipcarg_t) mr_res.triplet.index, NULL);
     vfs_release_phone(phone);
     ipcarg_t rc1;
     ipcarg_t rc2;
     async_wait_for(req1, &rc1);
     async_wait_for(req2, &rc2);
     if ((rc1 != EOK) || (rc2 != EOK)) {
         /* Mount failed, drop references to mr_node and mp_node. */
         vfs_node_put(mr_node);
         if (mp_node)
             vfs_node_put(mp_node);
+    }
     if (rc2 == EOK)
         ipc_answer_0(rid, rc1);
     else if (rc1 == EOK)
         ipc_answer_0(rid, rc2);
     else
         ipc_answer_0(rid, rc1);
+}
 void vfs_open(ipc_callid_t rid, ipc_call_t *request)
+{
     if (!vfs_files_init()) {
         ipc_answer_0(rid, ENOMEM);
         return;
+    }
     /*
      * The POSIX interface is open(path, oflag, mode).
      * We can receive oflags and mode along with the VFS_OPEN call; the path
      * will need to arrive in another call.
+     *
      * We also receive one private, non-POSIX set of flags called lflag
      * used to pass information to vfs_lookup_internal().
      */
     int lflag = IPC_GET_ARG1(*request);
     int oflag = IPC_GET_ARG2(*request);
     int mode = IPC_GET_ARG3(*request);
     size_t len;
     if (oflag & O_CREAT)
         lflag |= L_CREATE;
     if (oflag & O_EXCL)
         lflag |= L_EXCLUSIVE;
     ipc_callid_t callid;
     if (!ipc_data_write_receive(&callid, &len)) {
         ipc_answer_0(callid, EINVAL);
         ipc_answer_0(rid, EINVAL);
         return;
+    }
-    /*
-     * Now we are on the verge of accepting the path.
-     *
-     * There is one optimization we could do in the future: copy the path
-     * directly into the PLB using some kind of a callback.
-     */
     char *path = malloc(len + 1);
     if (!path) {
         ipc_answer_0(callid, ENOMEM);
         ipc_answer_0(rid, ENOMEM);
         return;
+    }
     int rc;
     if ((rc = ipc_data_write_finalize(callid, path, len))) {
         ipc_answer_0(rid, rc);
         free(path);
         return;
+    }
     path[len] = '\0';
     /*
      * Avoid the race condition in which the file can be deleted before we
      * find/create-and-lock the VFS node corresponding to the looked-up
      * triplet.
      */
     if (lflag & L_CREATE)
         rwlock_write_lock(&namespace_rwlock);
     else
         rwlock_read_lock(&namespace_rwlock);
     /* The path is now populated and we can call vfs_lookup_internal(). */
     vfs_lookup_res_t lr;
     rc = vfs_lookup_internal(path, lflag, &lr, NULL);
     if (rc) {
         if (lflag & L_CREATE)
             rwlock_write_unlock(&namespace_rwlock);
         else
             rwlock_read_unlock(&namespace_rwlock);
         ipc_answer_0(rid, rc);
         free(path);
         return;
+    }
     /* Path is no longer needed. */
     free(path);
     vfs_node_t *node = vfs_node_get(&lr);
     if (lflag & L_CREATE)
         rwlock_write_unlock(&namespace_rwlock);
     else
         rwlock_read_unlock(&namespace_rwlock);
     /* Truncate the file if requested and if necessary. */
     if (oflag & O_TRUNC) {
         rwlock_write_lock(&node->contents_rwlock);
         if (node->size) {
             rc = vfs_truncate_internal(node->fs_handle,
                 node->dev_handle, node->index, 0);
             if (rc) {
                 rwlock_write_unlock(&node->contents_rwlock);
                 vfs_node_put(node);
                 ipc_answer_0(rid, rc);
                 return;
+            }
             node->size = 0;
+        }
         rwlock_write_unlock(&node->contents_rwlock);
+    }
     /*
      * Get ourselves a file descriptor and the corresponding vfs_file_t
      * structure.
      */
     int fd = vfs_fd_alloc();
     if (fd < 0) {
         vfs_node_put(node);
         ipc_answer_0(rid, fd);
         return;
+    }
     vfs_file_t *file = vfs_file_get(fd);
     file->node = node;
     if (oflag & O_APPEND)
         file->append = true;
     /*
      * The following increase in reference count is for the fact that the
      * file is being opened and that a file structure is pointing to it.
      * It is necessary so that the file will not disappear when
      * vfs_node_put() is called. The reference will be dropped by the
      * respective VFS_CLOSE.
      */
     vfs_node_addref(node);
     vfs_node_put(node);
     /* Success! Return the new file descriptor to the client. */
     ipc_answer_1(rid, EOK, fd);
+}
 void vfs_close(ipc_callid_t rid, ipc_call_t *request)
+{
     int fd = IPC_GET_ARG1(*request);
     if (fd >= MAX_OPEN_FILES) {
         ipc_answer_0(rid, EBADF);
         return;
+    }
     vfs_fd_free(fd);
     ipc_answer_0(rid, EOK);
+}
 static void vfs_rdwr(ipc_callid_t rid, ipc_call_t *request, bool read)
+{
     /*
      * The following code strongly depends on the fact that the files data
      * structure can be only accessed by a single fibril and all file
      * operations are serialized (i.e. the reads and writes cannot
      * interleave and a file cannot be closed while it is being read).
+     *
      * Additional synchronization needs to be added once the table of
      * open files supports parallel access!
      */
     int fd = IPC_GET_ARG1(*request);
     /* Lookup the file structure corresponding to the file descriptor. */
     vfs_file_t *file = vfs_file_get(fd);
     if (!file) {
         ipc_answer_0(rid, ENOENT);
         return;
+    }
     /*
      * Now we need to receive a call with client's
      * IPC_M_DATA_READ/IPC_M_DATA_WRITE request.
      */
     ipc_callid_t callid;
     int res;
     if (read)
         res = ipc_data_read_receive(&callid, NULL);
     else
         res = ipc_data_write_receive(&callid, NULL);
     if (!res) {
         ipc_answer_0(callid, EINVAL);
         ipc_answer_0(rid, EINVAL);
         return;
+    }
     /*
      * Lock the open file structure so that no other thread can manipulate
      * the same open file at a time.
      */
     futex_down(&file->lock);
     /*
      * Lock the file's node so that no other client can read/write to it at
      * the same time.
      */
     if (read)
         rwlock_read_lock(&file->node->contents_rwlock);
     else
         rwlock_write_lock(&file->node->contents_rwlock);
     int fs_phone = vfs_grab_phone(file->node->fs_handle);
     /* Make a VFS_READ/VFS_WRITE request at the destination FS server. */
     aid_t msg;
     ipc_call_t answer;
     if (!read && file->append)
         file->pos = file->node->size;
     msg = async_send_3(fs_phone, IPC_GET_METHOD(*request),
         file->node->dev_handle, file->node->index, file->pos, &answer);
     /*
      * Forward the IPC_M_DATA_READ/IPC_M_DATA_WRITE request to the
      * destination FS server. The call will be routed as if sent by
      * ourselves. Note that call arguments are immutable in this case so we
      * don't have to bother.
      */
     ipc_forward_fast(callid, fs_phone, 0, 0, 0, IPC_FF_ROUTE_FROM_ME);
     vfs_release_phone(fs_phone);
     /* Wait for reply from the FS server. */
     ipcarg_t rc;
     async_wait_for(msg, &rc);
     size_t bytes = IPC_GET_ARG1(answer);
     /* Unlock the VFS node. */
     if (read)
         rwlock_read_unlock(&file->node->contents_rwlock);
     else {
         /* Update the cached version of node's size. */
         if (rc == EOK)
             file->node->size = IPC_GET_ARG2(answer);
         rwlock_write_unlock(&file->node->contents_rwlock);
+    }
     /* Update the position pointer and unlock the open file. */
     if (rc == EOK)
         file->pos += bytes;
     futex_up(&file->lock);
     /*
      * FS server's reply is the final result of the whole operation we
      * return to the client.
      */
     ipc_answer_1(rid, rc, bytes);
+}
 void vfs_read(ipc_callid_t rid, ipc_call_t *request)
+{
     vfs_rdwr(rid, request, true);
+}
 void vfs_write(ipc_callid_t rid, ipc_call_t *request)
+{
     vfs_rdwr(rid, request, false);
+}
 void vfs_seek(ipc_callid_t rid, ipc_call_t *request)
+{
     int fd = (int) IPC_GET_ARG1(*request);
     off_t off = (off_t) IPC_GET_ARG2(*request);
     int whence = (int) IPC_GET_ARG3(*request);
     /* Lookup the file structure corresponding to the file descriptor. */
     vfs_file_t *file = vfs_file_get(fd);
     if (!file) {
         ipc_answer_0(rid, ENOENT);
         return;
+    }
     off_t newpos;
     futex_down(&file->lock);
     if (whence == SEEK_SET) {
         file->pos = off;
         futex_up(&file->lock);
         ipc_answer_1(rid, EOK, off);
         return;
+    }
     if (whence == SEEK_CUR) {
         if (file->pos + off < file->pos) {
             futex_up(&file->lock);
             ipc_answer_0(rid, EOVERFLOW);
             return;
+        }
         file->pos += off;
         newpos = file->pos;
         futex_up(&file->lock);
         ipc_answer_1(rid, EOK, newpos);
         return;
+    }
     if (whence == SEEK_END) {
         rwlock_read_lock(&file->node->contents_rwlock);
         size_t size = file->node->size;
         rwlock_read_unlock(&file->node->contents_rwlock);
         if (size + off < size) {
             futex_up(&file->lock);
             ipc_answer_0(rid, EOVERFLOW);
             return;
+        }
         newpos = size + off;
         futex_up(&file->lock);
         ipc_answer_1(rid, EOK, newpos);
         return;
+    }
     futex_up(&file->lock);
     ipc_answer_0(rid, EINVAL);
+}
 int vfs_truncate_internal(int fs_handle, int dev_handle, unsigned long index,
     size_t size)
+{
     ipcarg_t rc;
     int fs_phone;
     fs_phone = vfs_grab_phone(fs_handle);
     rc = async_req_3_0(fs_phone, VFS_TRUNCATE, (ipcarg_t)dev_handle,
         (ipcarg_t)index, (ipcarg_t)size);
     vfs_release_phone(fs_phone);
     return (int)rc;
+}
 void vfs_truncate(ipc_callid_t rid, ipc_call_t *request)
+{
     int fd = IPC_GET_ARG1(*request);
     size_t size = IPC_GET_ARG2(*request);
     int rc;
     vfs_file_t *file = vfs_file_get(fd);
     if (!file) {
         ipc_answer_0(rid, ENOENT);
         return;
+    }
     futex_down(&file->lock);
     rwlock_write_lock(&file->node->contents_rwlock);
     rc = vfs_truncate_internal(file->node->fs_handle,
         file->node->dev_handle, file->node->index, size);
     if (rc == EOK)
         file->node->size = size;
     rwlock_write_unlock(&file->node->contents_rwlock);
     futex_up(&file->lock);
     ipc_answer_0(rid, (ipcarg_t)rc);
+}
 void vfs_mkdir(ipc_callid_t rid, ipc_call_t *request)
+{
     int mode = IPC_GET_ARG1(*request);
     size_t len;
     ipc_callid_t callid;
     if (!ipc_data_write_receive(&callid, &len)) {
         ipc_answer_0(callid, EINVAL);
         ipc_answer_0(rid, EINVAL);
         return;
+    }
-    /*
-     * Now we are on the verge of accepting the path.
-     *
-     * There is one optimization we could do in the future: copy the path
-     * directly into the PLB using some kind of a callback.
-     */
     char *path = malloc(len + 1);
     if (!path) {
         ipc_answer_0(callid, ENOMEM);
         ipc_answer_0(rid, ENOMEM);
         return;
+    }
     int rc;
     if ((rc = ipc_data_write_finalize(callid, path, len))) {
         ipc_answer_0(rid, rc);
         free(path);
         return;
+    }
     path[len] = '\0';
     rwlock_write_lock(&namespace_rwlock);
     int lflag = L_DIRECTORY | L_CREATE | L_EXCLUSIVE;
     rc = vfs_lookup_internal(path, lflag, NULL, NULL);
     rwlock_write_unlock(&namespace_rwlock);
     free(path);
     ipc_answer_0(rid, rc);
+}
 void vfs_unlink(ipc_callid_t rid, ipc_call_t *request)
+{
     int lflag = IPC_GET_ARG1(*request);
     size_t len;
     ipc_callid_t callid;
     if (!ipc_data_write_receive(&callid, &len)) {
         ipc_answer_0(callid, EINVAL);
         ipc_answer_0(rid, EINVAL);
         return;
+    }
-    /*
-     * Now we are on the verge of accepting the path.
-     *
-     * There is one optimization we could do in the future: copy the path
-     * directly into the PLB using some kind of a callback.
-     */
     char *path = malloc(len + 1);
     if (!path) {
         ipc_answer_0(callid, ENOMEM);
         ipc_answer_0(rid, ENOMEM);
         return;
+    }
     int rc;
     if ((rc = ipc_data_write_finalize(callid, path, len))) {
         ipc_answer_0(rid, rc);
         free(path);
         return;
+    }
     path[len] = '\0';
     rwlock_write_lock(&namespace_rwlock);
     lflag &= L_DIRECTORY;   /* sanitize lflag */
     vfs_lookup_res_t lr;
-    rc = vfs_lookup_internal(path, lflag | L_DESTROY, &lr, NULL);
+    rc = vfs_lookup_internal(path, lflag | L_UNLINK, &lr, NULL);
     free(path);
     if (rc != EOK) {
         rwlock_write_unlock(&namespace_rwlock);
         ipc_answer_0(rid, rc);
         return;
+    }
     /*
      * The name has already been unlinked by vfs_lookup_internal().
      * We have to get and put the VFS node to ensure that it is
      * VFS_DESTROY'ed after the last reference to it is dropped.
      */
     vfs_node_t *node = vfs_node_get(&lr);
     node->lnkcnt--;
     rwlock_write_unlock(&namespace_rwlock);
     vfs_node_put(node);
     ipc_answer_0(rid, EOK);
+}
+void vfs_rename(ipc_callid_t rid, ipc_call_t *request)
+{
+    size_t len;
+    ipc_callid_t callid;
+    int rc;
+    /* Retrieve the old path. */
+    if (!ipc_data_write_receive(&callid, &len)) {
+        ipc_answer_0(callid, EINVAL);
+        ipc_answer_0(rid, EINVAL);
+        return;
+    }
+    char *old = malloc(len + 1);
+    if (!old) {
+        ipc_answer_0(callid, ENOMEM);
+        ipc_answer_0(rid, ENOMEM);
+        return;
+    }
+    if ((rc = ipc_data_write_finalize(callid, old, len))) {
+        ipc_answer_0(rid, rc);
+        free(old);
+        return;
+    }
+    old[len] = '\0';
+    /* Retrieve the new path. */
+    if (!ipc_data_write_receive(&callid, &len)) {
+        ipc_answer_0(callid, EINVAL);
+        ipc_answer_0(rid, EINVAL);
+        free(old);
+        return;
+    }
+    char *new = malloc(len + 1);
+    if (!new) {
+        ipc_answer_0(callid, ENOMEM);
+        ipc_answer_0(rid, ENOMEM);
+        free(old);
+        return;
+    }
+    if ((rc = ipc_data_write_finalize(callid, new, len))) {
+        ipc_answer_0(rid, rc);
+        free(old);
+        free(new);
+        return;
+    }
+    new[len] = '\0';
+    char *oldc = canonify(old, &len);
+    char *newc = canonify(new, NULL);
+    if (!oldc || !newc) {
+        ipc_answer_0(rid, EINVAL);
+        free(old);
+        free(new);
+        return;
+    }
+    if (!strncmp(newc, oldc, len)) {
+        /* oldc is a prefix of newc */
+        ipc_answer_0(rid, EINVAL);
+        free(old);
+        free(new);
+        return;
+    }
+    vfs_lookup_res_t old_lr;
+    vfs_lookup_res_t new_lr;
+    vfs_lookup_res_t new_par_lr;
+    rwlock_write_lock(&namespace_rwlock);
+    /* Lookup the node belonging to the old file name. */
+    rc = vfs_lookup_internal(oldc, L_NONE, &old_lr, NULL);
+    if (rc != EOK) {
+        rwlock_write_unlock(&namespace_rwlock);
+        ipc_answer_0(rid, rc);
+        free(old);
+        free(new);
+        return;
+    }
+    vfs_node_t *old_node = vfs_node_get(&old_lr);
+    if (!old_node) {
+        rwlock_write_unlock(&namespace_rwlock);
+        ipc_answer_0(rid, ENOMEM);
+        free(old);
+        free(new);
+        return;
+    }
+    /* Lookup parent of the new file name. */
+    rc = vfs_lookup_internal(newc, L_PARENT, &new_par_lr, NULL);
+    if (rc != EOK) {
+        rwlock_write_unlock(&namespace_rwlock);
+        ipc_answer_0(rid, rc);
+        free(old);
+        free(new);
+        return;
+    }
+    /* Check whether linking to the same file system instance. */
+    if ((old_node->fs_handle != new_par_lr.triplet.fs_handle) ||
+        (old_node->dev_handle != new_par_lr.triplet.dev_handle)) {
+        rwlock_write_unlock(&namespace_rwlock);
+        ipc_answer_0(rid, EXDEV);   /* different file systems */
+        free(old);
+        free(new);
+        return;
+    }
+    /* Destroy the old link for the new name. */
+    vfs_node_t *new_node = NULL;
+    rc = vfs_lookup_internal(newc, L_UNLINK, &new_lr, NULL);
+    switch (rc) {
+    case ENOENT:
+        /* simply not in our way */
+        break;
+    case EOK:
+        new_node = vfs_node_get(&new_lr);
+        if (!new_node) {
+            rwlock_write_unlock(&namespace_rwlock);
+            ipc_answer_0(rid, ENOMEM);
+            free(old);
+            free(new);
+            return;
+        }
+        new_node->lnkcnt--;
+        break;
+    default:
+        rwlock_write_unlock(&namespace_rwlock);
+        ipc_answer_0(rid, ENOTEMPTY);
+        free(old);
+        free(new);
+        return;
+    }
+    /* Create the new link for the new name. */
+    rc = vfs_lookup_internal(newc, L_LINK, NULL, NULL, old_node->index);
+    if (rc != EOK) {
+        rwlock_write_unlock(&namespace_rwlock);
+        if (new_node)
+            vfs_node_put(new_node);
+        ipc_answer_0(rid, rc);
+        free(old);
+        free(new);
+        return;
+    }
+    old_node->lnkcnt++;
+    /* Destroy the link for the old name. */
+    rc = vfs_lookup_internal(oldc, L_UNLINK, NULL, NULL);
+    if (rc != EOK) {
+        rwlock_write_unlock(&namespace_rwlock);
+        vfs_node_put(old_node);
+        if (new_node)
+            vfs_node_put(new_node);
+        ipc_answer_0(rid, rc);
+        free(old);
+        free(new);
+        return;
+    }
+    old_node->lnkcnt--;
+    rwlock_write_unlock(&namespace_rwlock);
+    vfs_node_put(old_node);
+    if (new_node)
+        vfs_node_put(new_node);
+    free(old);
+    free(new);
+    ipc_answer_0(rid, EOK);
+}
 /**
  * @}
  */

Subversion Repositories HelenOS

(root)/branches/dynload/uspace/srv/vfs/vfs_ops.c @ 3150 – Rev 2752 → 2763