WebSVN – HelenOS – Diff – /branches/tracing/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
+ * @file vfs_ops.c
- * @brief   Operations that VFS offers to its clients.
+ * @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 <vfs/canonify.h>
 /* Forward declarations of static functions. */
 static int vfs_truncate_internal(fs_handle_t, dev_handle_t, fs_index_t, size_t);
+/** Pending mount structure. */
+typedef struct {
+    link_t link;
+    char *fs_name;            /**< File system name */
+    char *mp;                 /**< Mount point */
+    char *opts;       /**< Mount options. */
+    ipc_callid_t callid;      /**< Call ID waiting for the mount */
+    ipc_callid_t rid;         /**< Request ID */
+    dev_handle_t dev_handle;  /**< Device handle */
+} pending_req_t;
+LIST_INITIALIZE(pending_req);
 /**
  * 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);
 futex_t rootfs_futex = FUTEX_INITIALIZER;
 vfs_pair_t rootfs = {
     .fs_handle = 0,
     .dev_handle = 0
 };
-void vfs_mount(ipc_callid_t rid, ipc_call_t *request)
+static void vfs_mount_internal(ipc_callid_t rid, dev_handle_t dev_handle,
+    fs_handle_t fs_handle, char *mp, char *opts)
+{
-    dev_handle_t dev_handle;
+    vfs_lookup_res_t mp_res;
     vfs_node_t *mp_node = NULL;
-    ipc_callid_t callid;
-    ipc_call_t data;
+    ipcarg_t rc;
-    int rc;
     int phone;
-    size_t size;
+    aid_t msg;
-    /*
-     * 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 = (dev_handle_t)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.
-     */
-    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';
-    /*
-     * Wait for IPC_M_PING so that we can return an error if we don't know
-     * fs_name.
-     */
-    callid = async_get_call(&data);
-    if (IPC_GET_METHOD(data) != IPC_M_PING) {
-        ipc_answer_0(callid, ENOTSUP);
-        ipc_answer_0(rid, ENOTSUP);
-        return;
-    }
-    /*
-     * 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.
-     */
-    fs_handle_t fs_handle = fs_name_to_handle(fs_name, true);
-    if (!fs_handle) {
+    ipc_call_t answer;
-        ipc_answer_0(callid, ENOENT);
-        ipc_answer_0(rid, ENOENT);
-        return;
-    }
-    /* Acknowledge that we know fs_name. */
-    ipc_answer_0(callid, EOK);
-    /* 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. */
-    char *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';
     /* 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);
-        if ((size == 1) && (buf[0] == '/')) {
+        if (str_cmp(mp, "/") == 0) {
             /* Trying to mount root FS over root FS */
             rwlock_write_unlock(&namespace_rwlock);
             futex_up(&rootfs_futex);
-            free(buf);
             ipc_answer_0(rid, EBUSY);
             return;
+        }
-        rc = vfs_lookup_internal(buf, L_DIRECTORY, &mp_res, NULL);
+        rc = vfs_lookup_internal(mp, L_DIRECTORY, &mp_res, NULL);
         if (rc != EOK) {
             /* The lookup failed for some reason. */
             rwlock_write_unlock(&namespace_rwlock);
             futex_up(&rootfs_futex);
-            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);
-            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] == '/')) {
+        if (str_cmp(mp, "/") == 0) {
             vfs_lookup_res_t mr_res;
             vfs_node_t *mr_node;
-            ipcarg_t rindex;
+            fs_index_t rindex;
-            ipcarg_t rsize;
+            size_t rsize;
-            ipcarg_t rlnkcnt;
+            unsigned rlnkcnt;
             /*
              * For this simple, but important case,
              * we are almost done.
              */
-            free(buf);
             /* Tell the mountee that it is being mounted. */
             phone = vfs_grab_phone(fs_handle);
-            rc = async_req_1_3(phone, VFS_MOUNTED,
+            msg = async_send_1(phone, VFS_MOUNTED,
-                (ipcarg_t) dev_handle, &rindex, &rsize, &rlnkcnt);
+                (ipcarg_t) dev_handle, &answer);
+            /* send the mount options */
+            rc = ipc_data_write_start(phone, (void *)opts,
+                str_size(opts));
+            if (rc != EOK) {
+                async_wait_for(msg, NULL);
+                vfs_release_phone(phone);
+                futex_up(&rootfs_futex);
+                ipc_answer_0(rid, rc);
+                return;
+            }
+            async_wait_for(msg, &rc);
             vfs_release_phone(phone);
             if (rc != EOK) {
                 futex_up(&rootfs_futex);
                 ipc_answer_0(rid, rc);
                 return;
+            }
+            rindex = (fs_index_t) IPC_GET_ARG1(answer);
+            rsize = (size_t) IPC_GET_ARG2(answer);
+            rlnkcnt = (unsigned) IPC_GET_ARG3(answer);
             mr_res.triplet.fs_handle = fs_handle;
             mr_res.triplet.dev_handle = dev_handle;
-            mr_res.triplet.index = (fs_index_t) rindex;
+            mr_res.triplet.index = rindex;
-            mr_res.size = (size_t) rsize;
+            mr_res.size = rsize;
-            mr_res.lnkcnt = (unsigned) rlnkcnt;
+            mr_res.lnkcnt = rlnkcnt;
             mr_res.type = VFS_NODE_DIRECTORY;
             rootfs.fs_handle = fs_handle;
             rootfs.dev_handle = dev_handle;
             futex_up(&rootfs_futex);
             /* Add reference to the mounted root. */
             mr_node = vfs_node_get(&mr_res);
             assert(mr_node);
             ipc_answer_0(rid, rc);
             return;
         } else {
             /*
              * We can't resolve this without the root filesystem
              * being mounted first.
              */
             futex_up(&rootfs_futex);
-            free(buf);
             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.
      */
     phone = vfs_grab_phone(mp_res.triplet.fs_handle);
-    rc = async_req_4_0(phone, VFS_MOUNT,
+    msg = async_send_4(phone, VFS_MOUNT,
         (ipcarg_t) mp_res.triplet.dev_handle,
         (ipcarg_t) mp_res.triplet.index,
         (ipcarg_t) fs_handle,
-        (ipcarg_t) dev_handle);
+        (ipcarg_t) dev_handle, &answer);
+    /* send the mount options */
+    rc = ipc_data_write_start(phone, (void *)opts, str_size(opts));
+    if (rc != EOK) {
+        async_wait_for(msg, NULL);
+        vfs_release_phone(phone);
+        /* Mount failed, drop reference to mp_node. */
+        if (mp_node)
+            vfs_node_put(mp_node);
+        ipc_answer_0(rid, rc);
+        return;
+    }
+    async_wait_for(msg, &rc);
     vfs_release_phone(phone);
     if (rc != EOK) {
         /* Mount failed, drop reference to mp_node. */
         if (mp_node)
             vfs_node_put(mp_node);
+    }
     ipc_answer_0(rid, rc);
+}
+/** Process pending mount requests */
+void vfs_process_pending_mount()
+{
+    link_t *cur;
+loop:
+    for (cur = pending_req.next; cur != &pending_req; cur = cur->next) {
+        pending_req_t *pr = list_get_instance(cur, pending_req_t, link);
+        fs_handle_t fs_handle = fs_name_to_handle(pr->fs_name, true);
+        if (!fs_handle)
+            continue;
+        /* Acknowledge that we know fs_name. */
+        ipc_answer_0(pr->callid, EOK);
+        /* Do the mount */
+        vfs_mount_internal(pr->rid, pr->dev_handle, fs_handle, pr->mp,
+            pr->opts);
+        free(pr->fs_name);
+        free(pr->mp);
+        free(pr->opts);
+        list_remove(cur);
+        free(pr);
+        goto loop;
+    }
+}
+void vfs_mount(ipc_callid_t rid, ipc_call_t *request)
+{
+    /*
+     * 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_t dev_handle = (dev_handle_t) IPC_GET_ARG1(*request);
+    /*
+     * Mount flags are passed as ARG2.
+     */
+    unsigned int flags = (unsigned int) IPC_GET_ARG2(*request);
+    /*
+     * For now, don't make use of ARG3, but it can be used to
+     * carry mount options in the future.
+     */
+    /* We want the client to send us the mount point. */
+    ipc_callid_t callid;
+    size_t size;
+    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. */
+    char *mp = malloc(size + 1);
+    if (!mp) {
+        ipc_answer_0(callid, ENOMEM);
+        ipc_answer_0(rid, ENOMEM);
+        return;
+    }
+    /* Deliver the mount point. */
+    ipcarg_t retval = ipc_data_write_finalize(callid, mp, size);
+    if (retval != EOK) {
+        ipc_answer_0(rid, retval);
+        free(mp);
+        return;
+    }
+    mp[size] = '\0';
+    /* Now we expect to receive the mount options. */
+    if (!ipc_data_write_receive(&callid, &size)) {
+        ipc_answer_0(callid, EINVAL);
+        ipc_answer_0(rid, EINVAL);
+        free(mp);
+        return;
+    }
+    /* Check the offered options size. */
+    if (size < 0 || size > MAX_MNTOPTS_LEN) {
+        ipc_answer_0(callid, EINVAL);
+        ipc_answer_0(rid, EINVAL);
+        free(mp);
+        return;
+    }
+    /* Allocate buffer for the mount options. */
+    char *opts = (char *) malloc(size + 1);
+    if (!opts) {
+        ipc_answer_0(callid, ENOMEM);
+        ipc_answer_0(rid, ENOMEM);
+        free(mp);
+        return;
+    }
+    /* Deliver the mount options. */
+    retval = ipc_data_write_finalize(callid, opts, size);
+    if (retval != EOK) {
+        ipc_answer_0(rid, retval);
+        free(mp);
+        free(opts);
+        return;
+    }
+    opts[size] = '\0';
+    /*
+     * 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);
+        free(mp);
+        free(opts);
+        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);
+        free(mp);
+        free(opts);
+        return;
+    }
+    /*
+     * Allocate buffer for file system name.
+     */
+    char *fs_name = (char *) malloc(size + 1);
+    if (fs_name == NULL) {
+        ipc_answer_0(callid, ENOMEM);
+        ipc_answer_0(rid, ENOMEM);
+        free(mp);
+        free(opts);
+        return;
+    }
+    /* Deliver the file system name. */
+    retval = ipc_data_write_finalize(callid, fs_name, size);
+    if (retval != EOK) {
+        ipc_answer_0(rid, retval);
+        free(mp);
+        free(opts);
+        free(fs_name);
+        return;
+    }
+    fs_name[size] = '\0';
+    /*
+     * Wait for IPC_M_PING so that we can return an error if we don't know
+     * fs_name.
+     */
+    ipc_call_t data;
+    callid = async_get_call(&data);
+    if (IPC_GET_METHOD(data) != IPC_M_PING) {
+        ipc_answer_0(callid, ENOTSUP);
+        ipc_answer_0(rid, ENOTSUP);
+        free(mp);
+        free(opts);
+        free(fs_name);
+        return;
+    }
+    /*
+     * 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.
+     */
+    fs_handle_t fs_handle = fs_name_to_handle(fs_name, true);
+    if (!fs_handle) {
+        if (flags & IPC_FLAG_BLOCKING) {
+            pending_req_t *pr;
+            /* Blocking mount, add to pending list */
+            pr = (pending_req_t *) malloc(sizeof(pending_req_t));
+            if (!pr) {
+                ipc_answer_0(callid, ENOMEM);
+                ipc_answer_0(rid, ENOMEM);
+                free(mp);
+                free(fs_name);
+                free(opts);
+                return;
+            }
+            pr->fs_name = fs_name;
+            pr->mp = mp;
+            pr->opts = opts;
+            pr->callid = callid;
+            pr->rid = rid;
+            pr->dev_handle = dev_handle;
+            link_initialize(&pr->link);
+            list_append(&pr->link, &pending_req);
+            return;
+        }
+        ipc_answer_0(callid, ENOENT);
+        ipc_answer_0(rid, ENOENT);
+        free(mp);
+        free(fs_name);
+        free(opts);
+        return;
+    }
+    /* Acknowledge that we know fs_name. */
+    ipc_answer_0(callid, EOK);
+    /* Do the mount */
+    vfs_mount_internal(rid, dev_handle, fs_handle, mp, opts);
+    free(mp);
+    free(fs_name);
+    free(opts);
+}
 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;
     /*
      * Make sure that we are called with exactly one of L_FILE and
      * L_DIRECTORY.
      */
     if ((lflag & (L_FILE | L_DIRECTORY)) == 0 ||
         (lflag & (L_FILE | L_DIRECTORY)) == (L_FILE | L_DIRECTORY)) {
         ipc_answer_0(rid, EINVAL);
         return;
+    }
     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;
+    }
     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);
     int rc = vfs_fd_free(fd);
     ipc_answer_0(rid, rc);
+}
 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);
     if (file->node->type == VFS_NODE_DIRECTORY) {
         /*
          * Make sure that no one is modifying the namespace
          * while we are in readdir().
          */
         assert(read);
         rwlock_read_lock(&namespace_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);
     if (file->node->type == VFS_NODE_DIRECTORY)
         rwlock_read_unlock(&namespace_rwlock);
     /* 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(fs_handle_t fs_handle, dev_handle_t dev_handle,
     fs_index_t 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;
+    }
     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;
+    }
     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_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);
     futex_down(&nodes_futex);
     node->lnkcnt--;
     futex_up(&nodes_futex);
     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;
+    size_t olen, nlen;
     ipc_callid_t callid;
     int rc;
     /* Retrieve the old path. */
-    if (!ipc_data_write_receive(&callid, &len)) {
+    if (!ipc_data_write_receive(&callid, &olen)) {
         ipc_answer_0(callid, EINVAL);
         ipc_answer_0(rid, EINVAL);
         return;
+    }
-    char *old = malloc(len + 1);
+    char *old = malloc(olen + 1);
     if (!old) {
         ipc_answer_0(callid, ENOMEM);
         ipc_answer_0(rid, ENOMEM);
         return;
+    }
-    if ((rc = ipc_data_write_finalize(callid, old, len))) {
+    if ((rc = ipc_data_write_finalize(callid, old, olen))) {
         ipc_answer_0(rid, rc);
         free(old);
         return;
+    }
-    old[len] = '\0';
+    old[olen] = '\0';
     /* Retrieve the new path. */
-    if (!ipc_data_write_receive(&callid, &len)) {
+    if (!ipc_data_write_receive(&callid, &nlen)) {
         ipc_answer_0(callid, EINVAL);
         ipc_answer_0(rid, EINVAL);
         free(old);
         return;
+    }
-    char *new = malloc(len + 1);
+    char *new = malloc(nlen + 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))) {
+    if ((rc = ipc_data_write_finalize(callid, new, nlen))) {
         ipc_answer_0(rid, rc);
         free(old);
         free(new);
         return;
+    }
-    new[len] = '\0';
+    new[nlen] = '\0';
-    char *oldc = canonify(old, &len);
+    char *oldc = canonify(old, &olen);
-    char *newc = canonify(new, NULL);
+    char *newc = canonify(new, &nlen);
     if (!oldc || !newc) {
         ipc_answer_0(rid, EINVAL);
         free(old);
         free(new);
         return;
+    }
+    oldc[olen] = '\0';
+    newc[nlen] = '\0';
-    if (!strncmp(newc, oldc, len)) {
+    if ((!str_lcmp(newc, oldc, str_length(oldc))) &&
+        ((newc[str_length(oldc)] == '/') ||
+        (str_length(oldc) == 1) ||
+        (str_length(oldc) == str_length(newc)))) {
+            /*
-        /* oldc is a prefix of newc */
+         * oldc is a prefix of newc and either
+         * - newc continues with a / where oldc ends, or
+         * - oldc was / itself, or
+         * - oldc and newc are equal.
+         */
         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;
+    }
+    /* Determine the path to the parent of the node with the new name. */
+    char *parentc = str_dup(newc);
+    if (!parentc) {
+        rwlock_write_unlock(&namespace_rwlock);
+        ipc_answer_0(rid, rc);
+        free(old);
+        free(new);
+        return;
+    }
+    char *lastsl = str_rchr(parentc + 1, L'/');
+    if (lastsl)
+        *lastsl = '\0';
+    else
+        parentc[1] = '\0';
     /* Lookup parent of the new file name. */
-    rc = vfs_lookup_internal(newc, L_PARENT, &new_par_lr, NULL);
+    rc = vfs_lookup_internal(parentc, L_NONE, &new_par_lr, NULL);
+    free(parentc);  /* not needed anymore */
     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;
+        }
         futex_down(&nodes_futex);
         new_node->lnkcnt--;
         futex_up(&nodes_futex);
         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;
+    }
     futex_down(&nodes_futex);
     old_node->lnkcnt++;
     futex_up(&nodes_futex);
     /* 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;
+    }
     futex_down(&nodes_futex);
     old_node->lnkcnt--;
     futex_up(&nodes_futex);
     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/tracing/uspace/srv/vfs/vfs_ops.c @ 3675 – Rev 3675 → 4377