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, 130 insertions, 189 deletions

diff --git a/cpukit/libnetworking/lib/tftpDriver.c b/cpukit/libnetworking/lib/tftpDriver.c
index c5e6c6b075..0e284c1e5c 100644
--- a/cpukit/libnetworking/lib/tftpDriver.c
+++ b/cpukit/libnetworking/lib/tftpDriver.c
@@ -9,6 +9,9 @@
  * Saskatoon, Saskatchewan, CANADA
  * eric@skatter.usask.ca
  *
+ * Modifications to support reference counting in the file system are
+ * Copyright (c) 2012 embedded brains GmbH.
+ *
  *  $Id$
  *
  */
@@ -146,13 +149,6 @@ struct tftpStream {
 #define TFTPFS_VERBOSE (1 << 0)
 
 /*
- * Root node_access value
- * By using the address of the file system 
- * we ensure a unique value for this identifier.
- */
-#define ROOT_NODE_ACCESS(_fs) (_fs)
-
-/*
  * TFTP File system info.
  */
 typedef struct tftpfs_info_s {
@@ -170,39 +166,48 @@ typedef struct tftpfs_info_s {
  * Number of streams open at the same time
  */
 
-typedef const char *tftp_node;
 static const rtems_filesystem_operations_table  rtems_tftp_ops;
 static const rtems_filesystem_file_handlers_r   rtems_tftp_handlers;
 
+static bool rtems_tftp_is_directory(
+    const char *path,
+    size_t pathlen
+)
+{
+    return path [pathlen - 1] == '/';
+}
+
 int rtems_tftpfs_initialize(
   rtems_filesystem_mount_table_entry_t *mt_entry,
   const void                           *data
 )
 {
-  tftpfs_info_t     *fs;
   rtems_status_code  sc;
+  const char *device = mt_entry->dev;
+  size_t devicelen = strlen (device);
+  tftpfs_info_t *fs;
+  char *root_path;
 
-  mt_entry->mt_fs_root.handlers = &rtems_tftp_handlers;
-  mt_entry->mt_fs_root.ops      = &rtems_tftp_ops;
+  if (devicelen == 0)
+      rtems_set_errno_and_return_minus_one (ENXIO);
 
-  /*
-   *   We have no tftp filesystem specific data to maintain.  This
-   *   filesystem may only be mounted ONCE.
-   *
-   *   And we maintain no real filesystem nodes, so there is no real root.
-   */
+  fs = malloc (sizeof (*fs));
+  root_path = malloc (devicelen + 2);
+  if (root_path == NULL || fs == NULL)
+      goto error;
 
-  fs = malloc (sizeof (tftpfs_info_t));
-  if (!fs)
-      rtems_set_errno_and_return_minus_one (ENOMEM);
+  root_path = memcpy (root_path, device, devicelen);
+  root_path [devicelen] = '/';
+  root_path [devicelen + 1] = '\0';
 
   fs->flags = 0;
   fs->nStreams = 0;
   fs->tftpStreams = 0;
   
-  mt_entry->fs_info                  = fs;
-  mt_entry->mt_fs_root.node_access   = ROOT_NODE_ACCESS (fs);
-  mt_entry->mt_fs_root.node_access_2 = NULL;
+  mt_entry->fs_info = fs;
+  mt_entry->mt_fs_root->location.node_access = root_path;
+  mt_entry->mt_fs_root->location.handlers = &rtems_tftp_handlers;
+  mt_entry->mt_fs_root->location.ops = &rtems_tftp_ops;
   
   /*
    *  Now allocate a semaphore for mutual exclusion.
@@ -223,7 +228,7 @@ int rtems_tftpfs_initialize(
   );
 
   if (sc != RTEMS_SUCCESSFUL)
-      rtems_set_errno_and_return_minus_one (ENOMEM);
+      goto error;
 
   if (data) {
       char* config = (char*) data;
@@ -238,6 +243,13 @@ int rtems_tftpfs_initialize(
   }
   
   return 0;
+
+error:
+
+  free (fs);
+  free (root_path);
+
+  rtems_set_errno_and_return_minus_one (ENOMEM);
 }
 
 /*
@@ -254,7 +266,7 @@ releaseStream (tftpfs_info_t *fs, int s)
     rtems_semaphore_release (fs->tftp_mutex);
 }
 
-static int
+static void
 rtems_tftpfs_shutdown (rtems_filesystem_mount_table_entry_t* mt_entry)
 {
   tftpfs_info_t *fs = tftpfs_info_mount_table (mt_entry);
@@ -263,7 +275,7 @@ rtems_tftpfs_shutdown (rtems_filesystem_mount_table_entry_t* mt_entry)
       releaseStream (fs, s);
   rtems_semaphore_delete (fs->tftp_mutex);
   free (fs);
-  return 0;
+  free (mt_entry->mt_fs_root->location.node_access);
 }
 
 /*
@@ -418,17 +430,6 @@ sendAck (struct tftpStream *tp)
     return 0;
 }
 
-static int rtems_tftp_evaluate_for_make(
-   const char                         *path __attribute__((unused)),       /* IN     */
-   rtems_filesystem_location_info_t   *pathloc,    /* IN/OUT */
-   const char                        **name __attribute__((unused))        /* OUT    */
-)
-{
-  pathloc->node_access = NULL;
-  pathloc->node_access_2 = NULL;
-  rtems_set_errno_and_return_minus_one (EIO);
-}
-
 /*
  * Convert a path to canonical form
  */
@@ -483,62 +484,41 @@ fixPath (char *path)
     return;
 }
 
-static int rtems_tftp_eval_path(
-  const char                        *pathname,     /* IN     */
-  size_t                             pathnamelen,  /* IN     */		
-  int                                flags,        /* IN     */
-  rtems_filesystem_location_info_t  *pathloc       /* IN/OUT */
-)
+static void rtems_tftp_eval_path(rtems_filesystem_eval_path_context_t *self)
 {
-    tftpfs_info_t *fs;
-    char          *cp;
-
-    /*
-     * Get the file system info.
-     */
-    fs = tftpfs_info_pathloc (pathloc);
-
-    pathloc->handlers = &rtems_tftp_handlers;
-
-    /*
-     * Hack to provide the illusion of directories inside the TFTP file system.
-     * Paths ending in a / are assumed to be directories.
-     */
-    if (pathname[strlen(pathname)-1] == '/') {
-        int nal = 0;
-        if (pathloc->node_access != ROOT_NODE_ACCESS (fs))
-            nal = strlen(pathloc->node_access);
-        cp = malloc(nal + pathnamelen + 1);
-        if (cp == NULL)
-            rtems_set_errno_and_return_minus_one(ENOMEM);
-        if (nal)
-            memcpy (cp, pathloc->node_access, nal);
-        memcpy(cp + nal, pathname, pathnamelen);
-        cp[nal + pathnamelen] = '\0';
-        fixPath (cp);
-        pathloc->node_access = cp;
-    }
-    else {
-        if (pathnamelen) {
-            /*
-             * Reject it if it's not read-only or write-only.
-             */
-            flags &= RTEMS_LIBIO_PERMS_READ | RTEMS_LIBIO_PERMS_WRITE;
-            if ((flags != RTEMS_LIBIO_PERMS_READ)   \
-                && (flags != RTEMS_LIBIO_PERMS_WRITE))
-                rtems_set_errno_and_return_minus_one(EINVAL);
-
-            cp = malloc(pathnamelen + 1);
-            if (cp == NULL)
-                rtems_set_errno_and_return_minus_one(ENOMEM);
-            memcpy(cp, pathname, pathnamelen);
-            cp[pathnamelen] = '\0';
-            fixPath (cp);
-            pathloc->node_access_2 = cp;
+    int eval_flags = rtems_filesystem_eval_path_get_flags (self);
+
+    if ((eval_flags & RTEMS_LIBIO_MAKE) == 0) {
+        int rw = RTEMS_LIBIO_PERMS_READ | RTEMS_LIBIO_PERMS_WRITE;
+
+        if ((eval_flags & rw) != rw) {
+            rtems_filesystem_location_info_t *currentloc =
+                rtems_filesystem_eval_path_get_currentloc (self);
+            char *current = currentloc->node_access;
+            size_t currentlen = strlen (current);
+            const char *path = rtems_filesystem_eval_path_get_path (self);
+            size_t pathlen = rtems_filesystem_eval_path_get_pathlen (self);
+            size_t len = currentlen + pathlen;
+
+            rtems_filesystem_eval_path_clear_path (self);
+
+            current = realloc (current, len + 1);
+            if (current != NULL) {
+                memcpy (current + currentlen, path, pathlen);
+                current [len] = '\0';
+                if (!rtems_tftp_is_directory (current, len)) {
+                    fixPath (current);
+                }
+                currentloc->node_access = current;
+            } else {
+                rtems_filesystem_eval_path_error (self, ENOMEM);
+            }
+        } else {
+            rtems_filesystem_eval_path_error (self, EINVAL);
         }
+    } else {
+        rtems_filesystem_eval_path_error (self, EIO);
     }
-
-    return 0;
 }
 
 /*
@@ -547,8 +527,7 @@ static int rtems_tftp_eval_path(
 static int rtems_tftp_open_worker(
     rtems_libio_t *iop,
     char          *full_path_name,
-    uint32_t       flags,
-    uint32_t       mode __attribute__((unused))
+    int            oflag
 )
 {
     tftpfs_info_t        *fs;
@@ -680,7 +659,7 @@ static int rtems_tftp_open_worker(
         /*
          * Create the request
          */
-        if ((flags & O_ACCMODE) == O_RDONLY) {
+        if ((oflag & O_ACCMODE) == O_RDONLY) {
             tp->writing = 0;
             tp->pkbuf.tftpRWRQ.opcode = htons (TFTP_OPCODE_RRQ);
         }
@@ -751,91 +730,37 @@ static int rtems_tftp_open_worker(
     return 0;
 }
 
-/*
- * The IMFS open handler
- */
 static int rtems_tftp_open(
     rtems_libio_t *iop,
     const char    *new_name,
-    uint32_t       flags,
-    uint32_t       mode
+    int            oflag,
+    mode_t         mode
 )
 {
     tftpfs_info_t *fs;
-    const char    *device;
     char          *full_path_name;
-    char          *na;
-    char          *na2;
-    int           dlen;
-    int           nalen;
-    int           na2len;
-    int           sep1;
     int           err;
 
+    full_path_name = iop->pathinfo.node_access;
+
+    if (rtems_tftp_is_directory (full_path_name, strlen (full_path_name))) {
+        rtems_set_errno_and_return_minus_one (ENOTSUP);
+    }
+
     /*
      * Get the file system info.
      */
     fs = tftpfs_info_iop (iop);
-    
-    /*
-     * Tack the prefix directory if one exists from the device name.
-     */
-    device =
-      rtems_filesystem_mount_device (rtems_filesystem_location_mount (&iop->pathinfo));
-    dlen = strlen (device);
-    if (dlen == 0)
-        rtems_set_errno_and_return_minus_one (ENOENT);
-
-    if (iop->pathinfo.node_access_2 == NULL)
-        rtems_set_errno_and_return_minus_one (ENOENT);
-
-    if (iop->pathinfo.node_access != ROOT_NODE_ACCESS (fs)) {
-        na = iop->pathinfo.node_access;
-        nalen = strlen (na);
-    }     
-    else {
-        na = NULL;
-        nalen = 0;
-    }
-
-    na2 = iop->pathinfo.node_access_2;
-    
-    na2len = strlen (na2);
-
-    if (nalen) {
-      sep1 = 1;
-        if (na[nalen] == '/') {
-            sep1 = 0;
-            if (na2[0] == '/')
-                ++na2;
-        }
-        else {
-            if (na2[0] == '/')
-                sep1 = 0;
-            else
-                sep1 = 1;
-        }
-    }
-    else
-      sep1 = 0;
-
-    full_path_name = malloc (dlen + nalen + sep1 + na2len + 1);
-    if (full_path_name == NULL)
-        rtems_set_errno_and_return_minus_one(ENOMEM);
-    strcpy (full_path_name, device);
-    if (nalen)
-      strcat (full_path_name, na);
-    if (sep1)
-        strcat (full_path_name, "/");
-    strcat (full_path_name, na2);
-    fixPath (full_path_name);
 
     if (fs->flags & TFTPFS_VERBOSE)
-      printf ("TFTPFS: %s %s %s -> %s\n", device, na, na2, full_path_name);
+      printf ("TFTPFS: %s\n", full_path_name);
 
-    err = rtems_tftp_open_worker (iop, full_path_name, flags, mode);
-    free (full_path_name);
-    rtems_set_errno_and_return_minus_one(err);
+    err = rtems_tftp_open_worker (iop, full_path_name, oflag);
+    if (err != 0) {
+       rtems_set_errno_and_return_minus_one (err);
+    }
+
+    return 0;
 }
 
 /*
@@ -1051,52 +976,70 @@ static int rtems_tftp_ftruncate(
 }
 
 static rtems_filesystem_node_types_t rtems_tftp_node_type(
-     rtems_filesystem_location_info_t        *pathloc                 /* IN */
+    const rtems_filesystem_location_info_t *loc
 )
 {
-    tftpfs_info_t *fs = tftpfs_info_pathloc (pathloc);
-    if ((pathloc->node_access == NULL)
-     || (pathloc->node_access_2 != NULL)
-        || (pathloc->node_access == ROOT_NODE_ACCESS (fs)))
-        return RTEMS_FILESYSTEM_MEMORY_FILE;
-    return RTEMS_FILESYSTEM_DIRECTORY;
+    const char *path = loc->node_access;
+    size_t pathlen = strlen (path);
+
+    return rtems_tftp_is_directory (path, pathlen) ?
+        RTEMS_FILESYSTEM_DIRECTORY
+            : RTEMS_FILESYSTEM_MEMORY_FILE;
 }
 
-static int rtems_tftp_free_node_info(
-     rtems_filesystem_location_info_t        *pathloc                 /* IN */
+static int rtems_tftp_clone(
+    rtems_filesystem_location_info_t *loc
 )
 {
-    tftpfs_info_t *fs = tftpfs_info_pathloc (pathloc);
-    if (pathloc->node_access && \
-        (pathloc->node_access != ROOT_NODE_ACCESS (fs))) {
-        free (pathloc->node_access);
-        pathloc->node_access = NULL;
-    }
-    if (pathloc->node_access_2) {
-        free (pathloc->node_access_2);
-        pathloc->node_access_2 = NULL;
+    int rv = 0;
+
+    loc->node_access = strdup (loc->node_access);
+
+    if (loc->node_access == NULL) {
+        errno = ENOMEM;
+        rv = -1;
     }
-    return 0;
+
+    return rv;
 }
 
+static void rtems_tftp_free_node_info(
+    const rtems_filesystem_location_info_t *loc
+)
+{
+    free (loc->node_access);
+}
+
+static bool rtems_tftp_are_nodes_equal(
+  const rtems_filesystem_location_info_t *a,
+  const rtems_filesystem_location_info_t *b
+)
+{
+  return strcmp (a->node_access, b->node_access) == 0;
+}
 
 static const rtems_filesystem_operations_table  rtems_tftp_ops = {
-    .evalpath_h = rtems_tftp_eval_path,
-    .evalformake_h = rtems_tftp_evaluate_for_make,
+    .lock_h = rtems_filesystem_default_lock,
+    .unlock_h = rtems_filesystem_default_unlock,
+    .eval_path_h = rtems_tftp_eval_path,
     .link_h = rtems_filesystem_default_link,
-    .unlink_h = rtems_filesystem_default_unlink,
+    .are_nodes_equal_h = rtems_tftp_are_nodes_equal,
     .node_type_h = rtems_tftp_node_type,
     .mknod_h = rtems_filesystem_default_mknod,
+    .rmnod_h = rtems_filesystem_default_rmnod,
+    .fchmod_h = rtems_filesystem_default_fchmod,
     .chown_h = rtems_filesystem_default_chown,
+    .clonenod_h = rtems_tftp_clone,
     .freenod_h = rtems_tftp_free_node_info,
     .mount_h = rtems_filesystem_default_mount,
     .fsmount_me_h = rtems_tftpfs_initialize,
     .unmount_h = rtems_filesystem_default_unmount,
     .fsunmount_me_h = rtems_tftpfs_shutdown,
     .utime_h = rtems_filesystem_default_utime,
-    .eval_link_h = rtems_filesystem_default_evaluate_link,
     .symlink_h = rtems_filesystem_default_symlink,
-    .readlink_h = rtems_filesystem_default_readlink
+    .readlink_h = rtems_filesystem_default_readlink,
+    .rename_h = rtems_filesystem_default_rename,
+    .statvfs_h = rtems_filesystem_default_statvfs
 };
 
 static const rtems_filesystem_file_handlers_r rtems_tftp_handlers = {
@@ -1107,10 +1050,8 @@ static const rtems_filesystem_file_handlers_r rtems_tftp_handlers = {
    .ioctl_h = rtems_filesystem_default_ioctl,
    .lseek_h = rtems_filesystem_default_lseek,
    .fstat_h = rtems_filesystem_default_fstat,
-   .fchmod_h = rtems_filesystem_default_fchmod,
    .ftruncate_h = rtems_tftp_ftruncate,
    .fsync_h = rtems_filesystem_default_fsync,
    .fdatasync_h = rtems_filesystem_default_fdatasync,
-   .fcntl_h = rtems_filesystem_default_fcntl,
-   .rmnod_h = rtems_filesystem_default_rmnod
+   .fcntl_h = rtems_filesystem_default_fcntl
 };