--- /dev/null
+/****************************************************************************
+ *
+ * Copyright 2017 Samsung Electronics All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
+ * either express or implied. See the License for the specific
+ * language governing permissions and limitations under the License.
+ *
+ ****************************************************************************/
+/****************************************************************************
+ * fs/driver/fs_blockproxy.c
+ *
+ * Copyright (C) 2015-2016 Gregory Nutt. All rights reserved.
+ * Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * 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.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ * used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * 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.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+#include <tinyara/config.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <semaphore.h>
+#include <string.h>
+#include <errno.h>
+#include <assert.h>
+#include <debug.h>
+
+#include <tinyara/kmalloc.h>
+#include <tinyara/fs/fs.h>
+
+#if !defined(CONFIG_DISABLE_MOUNTPOINT) && \
+ !defined(CONFIG_DISABLE_PSEUDOFS_OPERATIONS)
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+static uint32_t g_devno;
+static sem_t g_devno_sem = SEM_INITIALIZER(1);
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: unique_chardev
+ *
+ * Description:
+ * Create a unique temporary device name in the /dev/ directory of the
+ * psuedo-file system. We cannot use mktemp for this because it will
+ * attempt to open() the file.
+ *
+ * Input parameters:
+ * None
+ *
+ * Returned Value:
+ * The allocated path to the device. This must be released by the caller
+ * to prevent memory links. NULL will be returned only the case where
+ * we fail to allocate memory.
+ *
+ ****************************************************************************/
+static FAR char *unique_chardev(void)
+{
+ struct stat statbuf;
+ char devbuf[16];
+ uint32_t devno;
+ int ret;
+
+ /* Loop until we get a unique device name */
+ for (; ; ) {
+ /* Get the semaphore protecting the path number */
+ while (sem_wait(&g_devno_sem) < 0) {
+ DEBUGASSERT(errno == EINTR);
+ }
+
+ /* Get the next device number and release the semaphore */
+ devno = ++g_devno;
+ sem_post(&g_devno_sem);
+
+ /* Construct the full device number */
+ devno &= 0xffffff;
+ snprintf(devbuf, 16, "/dev/tmp%06lx", (unsigned long)devno);
+
+ /* Make sure that file name is not in use */
+ ret = stat(devbuf, &statbuf);
+ if (ret < 0) {
+ DEBUGASSERT(errno == ENOENT);
+ return strdup(devbuf);
+ }
+
+ /* It is in use, try again */
+ }
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+/****************************************************************************
+ * Name: block_proxy
+ *
+ * Description:
+ * Create a temporary char driver using drivers/bch to mediate character
+ * oriented accessed to the block driver.
+ *
+ * Input parameters:
+ * blkdev - The path to the block driver
+ * oflags - Character driver open flags
+ *
+ * Returned Value:
+ * If positive, non-zero file descriptor is returned on success. This
+ * is the file descriptor of the nameless character driver that mediates
+ * accesses to the block driver.
+ *
+ * Errors that may be returned:
+ *
+ * ENOMEM - Failed to create a temporay path name.
+ *
+ * Plus:
+ *
+ * - Errors reported from bchdev_register()
+ * - Errors reported from open() or unlink()
+ *
+ ****************************************************************************/
+int block_proxy(FAR const char *blkdev, int oflags)
+{
+ FAR char *chardev;
+ bool readonly;
+ int ret;
+ int fd;
+
+ DEBUGASSERT(blkdev);
+ DEBUGASSERT((oflags & (O_CREAT | O_EXCL | O_APPEND | O_TRUNC)) == 0);
+
+ /* Create a unique temporary file name for the character device */
+ chardev = unique_chardev();
+ if (chardev == NULL) {
+ fdbg("ERROR: Failed to create temporary device name\n");
+ return -ENOMEM;
+ }
+
+ /* Should this character driver be read-only? */
+ readonly = ((oflags & O_WROK) == 0);
+
+ /* Wrap the block driver with an instance of the BCH driver */
+ ret = bchdev_register(blkdev, chardev, readonly);
+ if (ret < 0) {
+ fdbg("ERROR: bchdev_register(%s, %s) failed: %d\n",
+ blkdev, chardev, ret);
+
+ goto errout_with_chardev;
+ }
+
+ /* Open the newly created character driver */
+ oflags &= ~(O_CREAT | O_EXCL | O_APPEND | O_TRUNC);
+ fd = open(chardev, oflags);
+ if (fd < 0) {
+ ret = -errno;
+ fdbg("ERROR: Failed to open %s: %d\n", chardev, ret);
+ goto errout_with_bchdev;
+ }
+
+ /*
+ * Unlink the character device name. The driver instance will persist,
+ * provided that CONFIG_DISABLE_PSEUDOFS_OPERATIONS=y (otherwise, we have
+ * a problem here!)
+ */
+ ret = unlink(chardev);
+ if (ret < 0) {
+ ret = -errno;
+ fdbg("ERROR: Failed to unlink %s: %d\n", chardev, ret);
+ }
+
+ /*
+ * Free the allocate character driver name and return the open file
+ * descriptor.
+ */
+ kmm_free(chardev);
+ return fd;
+
+errout_with_bchdev:
+ (void)unlink(chardev);
+
+errout_with_chardev:
+ kmm_free(chardev);
+ return ret;
+}
+#endif /* !CONFIG_DISABLE_MOUNTPOINT && !CONFIG_DISABLE_PSEUDOFS_OPERATIONS */
projects / rtos / tinyara.git / commitdiff