Filesystem: Reference counting for locations

 o A new data structure rtems_filesystem_global_location_t was
   introduced to be used for
    o the mount point location in the mount table entry,
    o the file system root location in the mount table entry,
    o the root directory location in the user environment, and
    o the current directory location in the user environment.
   During the path evaluation global start locations are obtained to
   ensure that the current file system instance will be not unmounted in
   the meantime.
 o The user environment uses now reference counting and is protected
   from concurrent access.
 o The path evaluation process was completely rewritten and simplified.
   The IMFS, RFS, NFS, and DOSFS use now a generic path evaluation
   method.  Recursive calls in the path evaluation have been replaced
   with iteration to avoid stack overflows.  Only the evaluation of
   symbolic links is recursive.  No dynamic memory allocations and
   intermediate buffers are used in the high level path evaluation.  No
   global locks are held during the file system instance specific path
   evaluation process.
 o Recursive symbolic link evaluation is now limited by
   RTEMS_FILESYSTEM_SYMLOOP_MAX.  Applications can retrieve this value
   via sysconf().
 o The device file system (devFS) uses now no global variables and
   allocation from the workspace.  Node names are allocated from the
   heap.
 o The upper layer lseek() performs now some parameter checks.
 o The upper layer ftruncate() performs now some parameter checks.
 o unmask() is now restricted to the RWX flags and protected from
   concurrent access.
 o The fchmod_h and rmnod_h file system node handlers are now a file
   system operation.
 o The unlink_h operation has been removed.  All nodes are now destroyed
   with the rmnod_h operation.
 o New lock_h, unlock_h, clonenod_h, and are_nodes_equal_h file system
   operations.
 o The path evaluation and file system operations are now protected by
   per file system instance lock and unlock operations.
 o Fix and test file descriptor duplicate in fcntl().
 o New test fstests/fsnofs01.

1 files changed, 43 insertions, 83 deletions

diff --git a/cpukit/libfs/src/devfs/devfs.h b/cpukit/libfs/src/devfs/devfs.h
index 6e4f2478c7..758edf932b 100644
--- a/cpukit/libfs/src/devfs/devfs.h
+++ b/cpukit/libfs/src/devfs/devfs.h
@@ -17,38 +17,54 @@ extern "C" {
 /**
  *  This structure define the type of device table
  */
-
-typedef struct
-{
-  /** This member points to device name which is a null-terminated string */
-  const char               *device_name;
+typedef struct {
+  /** This member points to device name which is not a null-terminated string */
+  const char               *name;
   /** This member is the name length of a device */
-  uint32_t                  device_name_length;
+  size_t                    namelen;
   /** major number of a device */
   rtems_device_major_number major;
   /** minor number of a device */
   rtems_device_minor_number minor;
   /** device creation mode, only device file can be created */
   mode_t                    mode;
+} devFS_node;
 
-} rtems_device_name_t;
+typedef struct {
+  devFS_node *nodes;
+  size_t count;
+} devFS_data;
 
+/**
+ *  The following defines the device-only filesystem operating
+ *  operations.
+ */
 
+extern const rtems_filesystem_operations_table devFS_ops;
 
 /**
- *  This routine associates RTEMS status code with errno
+ *  The following defines the device-only filesystem operating
+ *  handlers.
  */
 
-extern int rtems_deviceio_errno(rtems_status_code code);
-
+extern const rtems_filesystem_file_handlers_r  devFS_file_handlers;
 
 /**
- *  The following defines the device table size. This values
- *  is configured during application configuration time by
- *  the user. The default value is set to 4.
+ *  This routine associates RTEMS status code with errno
  */
 
-extern uint32_t rtems_device_table_size;
+extern int rtems_deviceio_errno(rtems_status_code code);
+
+static inline const devFS_data *devFS_get_data(
+  const rtems_filesystem_location_info_t *loc
+)
+{
+  return loc->mt_entry->immutable_fs_info;
+}
+
+extern void devFS_eval_path(
+  rtems_filesystem_eval_path_context_t *ctx
+);
 
 /**
  *  This handler maps open operation to rtems_io_open.
@@ -62,8 +78,8 @@ extern uint32_t rtems_device_table_size;
 extern int devFS_open(
   rtems_libio_t *iop,
   const char    *pathname,
-  uint32_t       flag,
-  uint32_t       mode
+  int            oflag,
+  mode_t         mode
 );
 
 
@@ -142,8 +158,8 @@ extern int devFS_ioctl(
  */
 
 extern int devFS_stat(
-  rtems_filesystem_location_info_t *loc,
-  struct stat                      *buf
+  const rtems_filesystem_location_info_t *loc,
+  struct stat *buf
 );
 
 
@@ -153,63 +169,15 @@ extern int devFS_stat(
  *  Since this is a device-only filesystem, so there is only
  *  one node type in the system.
  *
- *  @param pathloc contains filesytem access information, this
+ *  @param loc contains filesytem access information, this
  *         parameter is ignored
  *  @retval always returns RTEMS_FILESYSTEM_DEVICE
  */
 
 extern rtems_filesystem_node_types_t devFS_node_type(
-  rtems_filesystem_location_info_t  *pathloc
+  const rtems_filesystem_location_info_t*loc
 );
 
-
-
-/**
- *  This routine is invoked to determine if 'pathname' exists.
- *  This routine first check access flags, then it searches
- *  the device table to get the information.
- *
- *  @param pathname device name to be searched
- *  @param flags access flags
- *  @param pathloc contains filesystem access information
- *  @retval upon success(pathname exists), this routines
- *  returns 0; if 'flag' is invalid, it returns -1 and errno
- *  is set to EIO; otherwise, it returns -1 and errno is set to ENOENT
- */
-
-extern int devFS_evaluate_path(
-  const char                        *pathname,
-  size_t                             pathnamelen,
-  int                                flags,
-  rtems_filesystem_location_info_t  *pathloc
-);
-
-
-/**
- *  This routine is given a path to evaluate and a valid start
- *  location. It is responsible for finding the parent node for
- *  a requested make command, setting pathloc information to
- *  identify the parent node, and setting the name pointer to
- *  the first character of the name of the new node. In device
- *  only filesystem, devices do not has a tree hierarchy, there
- *  are no parent-child relationship. So this routine is rather
- *  simple, it just set *name to path and returns
- *
- *  @param path device path to be evaluated
- *  @param pathloc contains filesystem access information, this
- *         parameter is ignored
- *  @param name
- *  @retval always returns 0
- */
-
-extern int devFS_evaluate_for_make(
-   const char                         *path,
-   rtems_filesystem_location_info_t   *pathloc,
-   const char                        **name
-);
-
-
-
 /**
  *  This routine is invoked upon registration of a new device
  *  file. It is responsible for creating a item in the main
@@ -217,21 +185,15 @@ extern int devFS_evaluate_for_make(
  *  sequential order, when found a empty slot, it fills the slot
  *  with proper values.
  *
- *  @param path the device file name to be registered
- *  @param mode file mode, this parameter is ignored
- *  @param dev  device major and minor number
- *  @param pathloc contains filesystem access information
- *  @retval upon success, this routine returns 0; if 'path'
- *  already exist, it returns -1 and errno is set to EEXIST;
- *  if device table is full, it returns -1 and errno is set
- *  to ENOMEM
+ *  @see rtems_filesystem_mknod_t.
  */
 
 extern int devFS_mknod(
-   const char                        *path,
-   mode_t                             mode,
-   dev_t                              dev,
-   rtems_filesystem_location_info_t  *pathloc
+  const rtems_filesystem_location_info_t *parentloc,
+  const char *name,
+  size_t namelen,
+  mode_t mode,
+  dev_t dev
 );
 
 
@@ -266,11 +228,9 @@ extern int devFS_initialize(
  *
  *  This routine is intended for debugging, and can be used by shell
  *  program to provide user with the system information.
- *
- *  @retval 0
  */
 
-extern int devFS_Show(void);
+extern void devFS_Show(void);
 
 #ifdef __cplusplus
 }