imfs: Replace devfs with an IMFS specialization

Add a simplified path evaluation function IMFS_eval_path_devfs() for a
device only IMFS configuration.

The code size can be further reduced by the application if it disables
the support for legacy IO drivers via:

  #define CONFIGURE_IMFS_DISABLE_MKNOD
  #define CONFIGURE_IMFS_DISABLE_MKNOD_DEVICE

Obsolete CONFIGURE_MAXIMUM_DEVICES.  Remove BSP_MAXIMUM_DEVICES.

Update #3894.
Update #3898.

11 files changed, 163 insertions, 485 deletions

diff --git a/cpukit/libfs/src/devfs/devclose.c b/cpukit/libfs/src/devfs/devclose.c
deleted file mode 100644
index e3ca969988..0000000000
--- a/cpukit/libfs/src/devfs/devclose.c
+++ /dev/null
@@ -1,29 +0,0 @@
-/**
- * @file
- *
- * @brief Maps Close Operation to rtems_io_close
- * @ingroup DevFsDeviceTable Define Device Table Type
- */
-
-/*
- *  The license and distribution terms for this file may be
- *  found in the file LICENSE in this distribution or at
- *  http://www.rtems.org/license/LICENSE.
- */
-
-#if HAVE_CONFIG_H
-  #include "config.h"
-#endif
-
-#include <rtems/devfs.h>
-
-#include <rtems/deviceio.h>
-
-int devFS_close(
-  rtems_libio_t *iop
-)
-{
-  const devFS_node *np = iop->pathinfo.node_access;
-
-  return rtems_deviceio_close( iop, np->major, np->minor );
-}
diff --git a/cpukit/libfs/src/devfs/devfs_eval.c b/cpukit/libfs/src/devfs/devfs_eval.c
deleted file mode 100644
index ba8e36fad0..0000000000
--- a/cpukit/libfs/src/devfs/devfs_eval.c
+++ /dev/null
@@ -1,95 +0,0 @@
-/**
- * @file
- *
- * @brief Evaluate Patch
- * @ingroup DevFsDeviceTable Define Device Table Type
- */
-
-/*
- *  The license and distribution terms for this file may be
- *  found in the file LICENSE in this distribution or at
- *  http://www.rtems.org/license/LICENSE.
- */
-
-#if HAVE_CONFIG_H
-  #include "config.h"
-#endif
-
-#include <string.h>
-
-#include <rtems/devfs.h>
-
-static devFS_node *devFS_search_node(
-  const devFS_data *data,
-  const char *path,
-  size_t pathlen,
-  devFS_node **free_node_ptr
-)
-{
-  size_t i = 0;
-  size_t n = data->count;
-  devFS_node *nodes = data->nodes;
-  devFS_node *node = NULL;
-  devFS_node *free_node = NULL;
-
-  for (i = 0; (free_node == NULL || node == NULL) && i < n; ++i) {
-    devFS_node *current = nodes + i;
-
-    if (current->name != NULL) {
-      if (
-        current->namelen == pathlen
-          && memcmp(current->name, path, pathlen) == 0
-      ) {
-        node = current;
-      }
-    } else {
-      free_node = current;
-    }
-  }
-
-  *free_node_ptr = free_node;
-
-  return node;
-}
-
-void devFS_eval_path(
-  rtems_filesystem_eval_path_context_t *ctx
-)
-{
-  rtems_filesystem_location_info_t *currentloc =
-    rtems_filesystem_eval_path_get_currentloc(ctx);
-  devFS_node *free_node;
-  devFS_node *node = devFS_search_node(
-    devFS_get_data(currentloc),
-    rtems_filesystem_eval_path_get_path(ctx),
-    rtems_filesystem_eval_path_get_pathlen(ctx),
-    &free_node
-  );
-  int eval_flags = rtems_filesystem_eval_path_get_flags(ctx);
-
-  if (node != NULL) {
-    if ((eval_flags & RTEMS_FS_EXCLUSIVE) == 0) {
-      currentloc->node_access = node;
-      rtems_filesystem_eval_path_clear_path(ctx);
-    } else {
-      rtems_filesystem_eval_path_error(ctx, EEXIST);
-    }
-  } else {
-    if ((eval_flags & RTEMS_FS_MAKE) != 0) {
-      if (free_node != NULL) {
-        free_node->mode = S_IRWXU | S_IRWXG | S_IRWXO;
-        currentloc->node_access = free_node;
-        rtems_filesystem_eval_path_set_token(
-          ctx,
-          rtems_filesystem_eval_path_get_path(ctx),
-          rtems_filesystem_eval_path_get_pathlen(ctx)
-        );
-        rtems_filesystem_eval_path_clear_path(ctx);
-      } else {
-        rtems_filesystem_eval_path_error(ctx, ENOSPC);
-      }
-    } else {
-      rtems_filesystem_eval_path_error(ctx, ENOENT);
-    }
-  }
-}
diff --git a/cpukit/libfs/src/devfs/devfs_init.c b/cpukit/libfs/src/devfs/devfs_init.c
deleted file mode 100644
index e8ad761f29..0000000000
--- a/cpukit/libfs/src/devfs/devfs_init.c
+++ /dev/null
@@ -1,79 +0,0 @@
-/**
- * @file
- *
- * @brief Creates the Main Device Table
- * @ingroup DevFsDeviceTable Define Device Table Type
- */
-
-/*
- *  The license and distribution terms for this file may be
- *  found in the file LICENSE in this distribution or at
- *  http://www.rtems.org/license/LICENSE.
- */
-
-#if HAVE_CONFIG_H
-  #include "config.h"
-#endif
-
-#include <rtems/devfs.h>
-
-const rtems_filesystem_operations_table devFS_ops = {
-  .lock_h = rtems_filesystem_default_lock,
-  .unlock_h = rtems_filesystem_default_unlock,
-  .eval_path_h = devFS_eval_path,
-  .link_h = rtems_filesystem_default_link,
-  .are_nodes_equal_h = rtems_filesystem_default_are_nodes_equal,
-  .mknod_h = devFS_mknod,
-  .rmnod_h = rtems_filesystem_default_rmnod,
-  .fchmod_h = rtems_filesystem_default_fchmod,
-  .chown_h = rtems_filesystem_default_chown,
-  .clonenod_h = rtems_filesystem_default_clonenode,
-  .freenod_h = rtems_filesystem_default_freenode,
-  .mount_h = rtems_filesystem_default_mount,
-  .unmount_h = rtems_filesystem_default_unmount,
-  .fsunmount_me_h = rtems_filesystem_default_fsunmount,
-  .utime_h = rtems_filesystem_default_utime,
-  .symlink_h = rtems_filesystem_default_symlink,
-  .readlink_h = rtems_filesystem_default_readlink,
-  .rename_h = rtems_filesystem_default_rename,
-  .statvfs_h = rtems_filesystem_default_statvfs
-};
-
-const rtems_filesystem_file_handlers_r devFS_file_handlers = {
-  .open_h = devFS_open,
-  .close_h = devFS_close,
-  .read_h = devFS_read,
-  .write_h = devFS_write,
-  .ioctl_h = devFS_ioctl,
-  .lseek_h = rtems_filesystem_default_lseek_file,
-  .fstat_h = devFS_stat,
-  .ftruncate_h = rtems_filesystem_default_ftruncate,
-  .fsync_h = rtems_filesystem_default_fsync_or_fdatasync,
-  .fdatasync_h = rtems_filesystem_default_fsync_or_fdatasync,
-  .fcntl_h = rtems_filesystem_default_fcntl,
-  .kqfilter_h = rtems_filesystem_default_kqfilter,
-  .mmap_h = rtems_filesystem_default_mmap,
-  .poll_h = rtems_filesystem_default_poll,
-  .readv_h = rtems_filesystem_default_readv,
-  .writev_h = rtems_filesystem_default_writev
-};
-
-int devFS_initialize(
-  rtems_filesystem_mount_table_entry_t *mt_entry,
-  const void *data
-)
-{
-  int rv = 0;
-
-  if (data != NULL) {
-    mt_entry->ops = &devFS_ops;
-    mt_entry->immutable_fs_info = data;
-    mt_entry->mt_fs_root->location.handlers = &devFS_file_handlers;
-  } else {
-    errno = EINVAL;
-    rv = -1;
-  }
-
-  return rv;
-}
-
diff --git a/cpukit/libfs/src/devfs/devfs_mknod.c b/cpukit/libfs/src/devfs/devfs_mknod.c
deleted file mode 100644
index 3b86d8c192..0000000000
--- a/cpukit/libfs/src/devfs/devfs_mknod.c
+++ /dev/null
@@ -1,63 +0,0 @@
-/**
- * @file
- *
- * @brief Creates an item in the main device table.
- * @ingroup DevFsDeviceTable Define Device Table Type
- */
-
-/*
- *  The license and distribution terms for this file may be
- *  found in the file LICENSE in this distribution or at
- *  http://www.rtems.org/license/LICENSE.
- */
-
-#if HAVE_CONFIG_H
-  #include "config.h"
-#endif
-
-#include <sys/stat.h>
-#include <stdlib.h>
-#include <string.h>
-
-#include <rtems/devfs.h>
-
-int devFS_mknod(
-  const rtems_filesystem_location_info_t *parentloc,
-  const char *name,
-  size_t namelen,
-  mode_t mode,
-  dev_t dev
-)
-{
-  int rv = 0;
-
-  if (namelen != 3 || name [0] != 'd' || name [1] != 'e' || name [2] != 'v') {
-    if (S_ISBLK(mode) || S_ISCHR(mode)) {
-      char *dupname = malloc(namelen);
-
-      if (dupname != NULL) {
-        devFS_node *node = parentloc->node_access;
-
-        node->name = dupname;
-        node->namelen = namelen;
-        node->major = rtems_filesystem_dev_major_t(dev);
-        node->minor = rtems_filesystem_dev_minor_t(dev);
-        node->mode = mode;
-        memcpy(dupname, name, namelen);
-      } else {
-        errno = ENOMEM;
-        rv = -1;
-      }
-    } else {
-      errno = ENOTSUP;
-      rv = -1;
-    }
-  } else {
-    if (!S_ISDIR(mode)) {
-      errno = ENOTSUP;
-      rv = -1;
-    }
-  }
-
-  return rv;
-}
diff --git a/cpukit/libfs/src/devfs/devfs_show.c b/cpukit/libfs/src/devfs/devfs_show.c
deleted file mode 100644
index 07e67c6f51..0000000000
--- a/cpukit/libfs/src/devfs/devfs_show.c
+++ /dev/null
@@ -1,51 +0,0 @@
-/**
- * @file
- *
- * @brief Retrieves and Prints all the Device Registered in System
- * @ingroup DevFsDeviceTable Define Device Table Type
- */
-
-/*
- *  The license and distribution terms for this file may be
- *  found in the file LICENSE in this distribution or at
- *  http://www.rtems.org/license/LICENSE.
- */
-
-#if HAVE_CONFIG_H
-  #include "config.h"
-#endif
-
-#include <rtems/devfs.h>
-
-#include <rtems/bspIo.h>
-
-void devFS_Show(void)
-{
-  rtems_filesystem_location_info_t *rootloc = &rtems_filesystem_root->location;
-
-  if (rootloc->mt_entry->ops == &devFS_ops) {
-    const devFS_data *data = devFS_get_data(rootloc);
-    size_t i = 0;
-    size_t n = data->count;
-    devFS_node *nodes = data->nodes;
-
-    for (i = 0; i < n; ++i) {
-      devFS_node *current = nodes + i;
-
-      if (current->name != NULL) {
-        size_t j = 0;
-        size_t m = current->namelen;
-
-        printk("/");
-        for (j = 0; j < m; ++j) {
-          printk("%c", current->name [j]);
-        }
-        printk(
-          " %lu %lu\n",
-          (unsigned long) current->major,
-          (unsigned long) current->minor
-        );
-      }
-    }
-  }
-}
diff --git a/cpukit/libfs/src/devfs/devioctl.c b/cpukit/libfs/src/devfs/devioctl.c
deleted file mode 100644
index 693d30e825..0000000000
--- a/cpukit/libfs/src/devfs/devioctl.c
+++ /dev/null
@@ -1,31 +0,0 @@
-/**
- * @file
- *
- * @brief Maps ioctl Operation to rtems_io_ioctl
- * @ingroup DevFsDeviceTable Define Device Table Type
- */
-
-/*
- *  The license and distribution terms for this file may be
- *  found in the file LICENSE in this distribution or at
- *  http://www.rtems.org/license/LICENSE.
- */
-
-#if HAVE_CONFIG_H
-  #include "config.h"
-#endif
-
-#include <rtems/devfs.h>
-
-#include <rtems/deviceio.h>
-
-int devFS_ioctl(
-  rtems_libio_t   *iop,
-  ioctl_command_t  command,
-  void            *buffer
-)
-{
-  const devFS_node *np = iop->pathinfo.node_access;
-
-  return rtems_deviceio_control( iop, command, buffer, np->major, np->minor );
-}
diff --git a/cpukit/libfs/src/devfs/devopen.c b/cpukit/libfs/src/devfs/devopen.c
deleted file mode 100644
index d6d5c8062d..0000000000
--- a/cpukit/libfs/src/devfs/devopen.c
+++ /dev/null
@@ -1,39 +0,0 @@
-/**
- * @file
- *
- * @brief Maps Open Operation to rtems_io_open
- * @ingroup DevFsDeviceTable Define Device Table Type
- */
-
-/*
- *  The license and distribution terms for this file may be
- *  found in the file LICENSE in this distribution or at
- *  http://www.rtems.org/license/LICENSE.
- */
-
-#if HAVE_CONFIG_H
-  #include "config.h"
-#endif
-
-#include <rtems/devfs.h>
-
-#include <rtems/deviceio.h>
-
-int devFS_open(
-  rtems_libio_t *iop,
-  const char    *pathname,
-  int            oflag,
-  mode_t         mode
-)
-{
-  const devFS_node *np = iop->pathinfo.node_access;
-
-  return rtems_deviceio_open(
-    iop,
-    pathname,
-    oflag,
-    mode,
-    np->major,
-    np->minor
-  );
-}
diff --git a/cpukit/libfs/src/devfs/devread.c b/cpukit/libfs/src/devfs/devread.c
deleted file mode 100644
index 8ae3e84b65..0000000000
--- a/cpukit/libfs/src/devfs/devread.c
+++ /dev/null
@@ -1,31 +0,0 @@
-/**
- * @file
- *
- * @brief DevFS Read
- * @ingroup Read Operation to rtems_io_read
- */
-
-/*
- *  The license and distribution terms for this file may be
- *  found in the file LICENSE in this distribution or at
- *  http://www.rtems.org/license/LICENSE.
- */
-
-#if HAVE_CONFIG_H
-  #include "config.h"
-#endif
-
-#include <rtems/devfs.h>
-
-#include <rtems/deviceio.h>
-
-ssize_t devFS_read(
-  rtems_libio_t *iop,
-  void          *buffer,
-  size_t         count
-)
-{
-  const devFS_node *np = iop->pathinfo.node_access;
-
-  return rtems_deviceio_read( iop, buffer, count, np->major, np->minor );
-}
diff --git a/cpukit/libfs/src/devfs/devstat.c b/cpukit/libfs/src/devfs/devstat.c
deleted file mode 100644
index c88f729924..0000000000
--- a/cpukit/libfs/src/devfs/devstat.c
+++ /dev/null
@@ -1,36 +0,0 @@
-/**
- * @file
- *
- * @brief Gets the Device File Information
- * @ingroup DevFsDeviceTable Define Device Table Type
- */
-
-/*
- *  The license and distribution terms for this file may be
- *  found in the file LICENSE in this distribution or at
- *  http://www.rtems.org/license/LICENSE.
- */
-
-#if HAVE_CONFIG_H
-  #include "config.h"
-#endif
-
-#include <rtems/devfs.h>
-
-int devFS_stat(
-  const rtems_filesystem_location_info_t *loc,
-  struct stat *buf
-)
-{
-  int rv = 0;
-  const devFS_node *the_dev = loc->node_access;
-
-  if (the_dev != NULL) {
-    buf->st_rdev = rtems_filesystem_make_dev_t( the_dev->major, the_dev->minor );
-    buf->st_mode = the_dev->mode;
-  } else {
-    rv = rtems_filesystem_default_fstat(loc, buf);
-  }
-
-  return rv;
-}
diff --git a/cpukit/libfs/src/devfs/devwrite.c b/cpukit/libfs/src/devfs/devwrite.c
deleted file mode 100644
index 7fd8006776..0000000000
--- a/cpukit/libfs/src/devfs/devwrite.c
+++ /dev/null
@@ -1,31 +0,0 @@
-/**
- * @file
- *
- * @brief Writes Operation to rtems_io_write
- * @ingroup DevFsDeviceTable Define Device Table Type
- */
-
-/*
- *  The license and distribution terms for this file may be
- *  found in the file LICENSE in this distribution or at
- *  http://www.rtems.org/license/LICENSE.
- */
-
-#if HAVE_CONFIG_H
-  #include "config.h"
-#endif
-
-#include <rtems/devfs.h>
-
-#include <rtems/deviceio.h>
-
-ssize_t devFS_write(
-  rtems_libio_t *iop,
-  const void    *buffer,
-  size_t         count
-)
-{
-  const devFS_node *np = iop->pathinfo.node_access;
-
-  return rtems_deviceio_write( iop, buffer, count, np->major, np->minor );
-}
diff --git a/cpukit/libfs/src/imfs/imfs_eval_devfs.c b/cpukit/libfs/src/imfs/imfs_eval_devfs.c
new file mode 100644
index 0000000000..d25e4ff8e2
--- /dev/null
+++ b/cpukit/libfs/src/imfs/imfs_eval_devfs.c
@@ -0,0 +1,163 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+
+/**
+ * @file
+ *
+ * @ingroup ClassicIO
+ *
+ * @brief Implementation of IMFS_eval_path_devfs().
+ */
+
+/*
+ * Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT OWNER OR CONTRIBUTORS 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.
+ */
+
+#if HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <rtems/imfs.h>
+
+#include <string.h>
+
+typedef struct {
+  uint8_t len;
+  char name[3];
+} IMFS_devfs_dir;
+
+static const IMFS_devfs_dir IMFS_devfs_dirs[] = {
+  { .len = 1, .name = { '/' } },
+  { .len = 1, .name = { '.' } },
+  { .len = 2, .name = { '.', '.' } },
+  { .len = 3, .name = { 'd', 'e', 'v' } }
+};
+
+static IMFS_jnode_t *IMFS_devfs_is_dir(
+  rtems_filesystem_eval_path_context_t *ctx,
+  IMFS_directory_t                     *dir
+)
+{
+  const char *path;
+  size_t      pathlen;
+  size_t      i;
+
+  path = rtems_filesystem_eval_path_get_path( ctx );
+  pathlen = rtems_filesystem_eval_path_get_pathlen( ctx );
+
+  for ( i = 0; i < RTEMS_ARRAY_SIZE( IMFS_devfs_dirs ); ++i ) {
+    bool match;
+
+    match = IMFS_devfs_dirs[ i ].len == pathlen
+      && memcmp( IMFS_devfs_dirs[ i ].name, path, pathlen ) == 0;
+
+    if ( match ) {
+      int eval_flags;
+
+      eval_flags = rtems_filesystem_eval_path_get_flags( ctx );
+      eval_flags &= ~RTEMS_FS_EXCLUSIVE;
+      rtems_filesystem_eval_path_set_flags( ctx, eval_flags );
+      rtems_filesystem_eval_path_clear_path( ctx );
+      return &dir->Node;
+    }
+  }
+
+  return NULL;
+}
+
+static IMFS_jnode_t *IMFS_devfs_search(
+  rtems_filesystem_eval_path_context_t *ctx,
+  IMFS_directory_t                     *dir
+)
+{
+  const char          *path;
+  size_t               pathlen;
+  rtems_chain_control *entries;
+  rtems_chain_node    *current;
+  rtems_chain_node    *tail;
+
+  path = rtems_filesystem_eval_path_get_path( ctx );
+  pathlen = rtems_filesystem_eval_path_get_pathlen( ctx );
+  entries = &dir->Entries;
+  current = rtems_chain_first( entries );
+  tail = rtems_chain_tail( entries );
+
+  while ( current != tail ) {
+    IMFS_jnode_t *entry;
+    bool          match;
+
+    entry = (IMFS_jnode_t *) current;
+    match = entry->namelen == pathlen
+      && memcmp( entry->name, path, pathlen ) == 0;
+
+    if ( match ) {
+      return entry;
+    }
+
+    current = rtems_chain_next( current );
+  }
+
+  return NULL;
+}
+
+void IMFS_eval_path_devfs( rtems_filesystem_eval_path_context_t *ctx )
+{
+  rtems_filesystem_location_info_t *currentloc;
+  IMFS_directory_t                 *dir;
+  IMFS_jnode_t                     *entry;
+
+  currentloc = rtems_filesystem_eval_path_get_currentloc( ctx );
+  dir = currentloc->node_access;
+
+  entry = IMFS_devfs_is_dir( ctx, dir );
+
+  if ( entry != NULL ) {
+    return;
+  }
+
+  entry = IMFS_devfs_search( ctx, dir );
+
+  if ( entry != NULL ) {
+    int eval_flags;
+
+    eval_flags = rtems_filesystem_eval_path_get_flags( ctx );
+
+    if ( ( eval_flags & RTEMS_FS_EXCLUSIVE ) == 0 ) {
+      --dir->Node.reference_count;
+      ++entry->reference_count;
+      currentloc->node_access = entry;
+      currentloc->node_access_2 = IMFS_generic_get_context_by_node( entry );
+      IMFS_Set_handlers( currentloc );
+      rtems_filesystem_eval_path_clear_path( ctx );
+    } else {
+      rtems_filesystem_eval_path_error( ctx, EEXIST );
+    }
+  } else {
+    rtems_filesystem_eval_path_set_token(
+      ctx,
+      rtems_filesystem_eval_path_get_path( ctx ),
+      rtems_filesystem_eval_path_get_pathlen( ctx )
+    );
+    rtems_filesystem_eval_path_clear_path( ctx );
+  }
+}