drivers/loop: Add a loop character device that can be used to setup and teardown loop devices

include/nuttx/fs/fs.h

@@ -897,29 +897,6 @@ void devcrypto_register(void);
 
 void devzero_register(void);
 
-/* drivers/loop.c ***********************************************************/
-/****************************************************************************
- * Name: losetup
- *
- * Description:
- *   Setup the loop device so that it exports the file referenced by 'filename'
- *   as a block device.
- *
- ****************************************************************************/
-
-int losetup(FAR const char *devname, FAR const char *filename,
-            uint16_t sectsize, off_t offset, bool readonly);
-
-/****************************************************************************
- * Name: loteardown
- *
- * Description:
- *   Undo the setup performed by losetup
- *
- ****************************************************************************/
-
-int loteardown(FAR const char *devname);
-
 /* drivers/bch/bchdev_register.c ********************************************/
 /****************************************************************************
  * Name: bchdev_register

include/nuttx/fs/ioctl.h

@@ -80,6 +80,7 @@
 #define _BTNBASE        (0x1b00) /* Button ioctl commands */
 #define _ULEDBASE       (0x1c00) /* User LED ioctl commands */
 #define _ZCBASE         (0x1d00) /* Zero Cross ioctl commands */
+#define _LOOPBASE       (0x1e00) /* Loop device commands */
 
 /* boardctl commands share the same number space */
 
@@ -360,6 +361,12 @@
 #define _ZCIOCVALID(c)    (_IOC_TYPE(c)==_ZCBASE)
 #define _ZCIOC(nr)        _IOC(_ZCBASE,nr)
 
+/* Loop driver ioctl definitions ********************************************/
+/* (see nuttx/include/fs/loop.h */
+
+#define _LOOPIOCVALID(c)  (_IOC_TYPE(c)==_LOOPBASE)
+#define _LOOPIOC(nr)      _IOC(_LOOPBASE,nr)
+
 /* boardctl() command definitions *******************************************/
 
 #define _BOARDIOCVALID(c) (_IOC_TYPE(c)==_BOARDBASE)

include/nuttx/fs/loop.h

@@ -0,0 +1,145 @@
+/****************************************************************************
+ * include/nuttx/fs/loop.h
+ *
+ *   Copyright (C) 2015 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.
+ *
+ ****************************************************************************/
+
+#ifndef __INCLUDE_NUTTX_FS_LOOP_H
+#define __INCLUDE_NUTTX_FS_LOOP_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#include <nuttx/fs/ioctl.h>
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+#ifdef CONFIG_DEV_LOOP
+/* Loop device IOCTL commands */
+
+/* Command:      LOOPIOC_SETUP
+ * Description:  Setup the loop device
+ * Argument:     A pointer to a read-only instance of struct losetup_s.
+ * Dependencies: The loop device must be enabled (CONFIG_DEV_LOOP=y)
+ */
+
+/* Command:      LOOPIOC_TEARDOWN
+ * Description:  Teardown a loop device previously setup vis LOOPIOC_SETUP
+ * Argument:     A read-able pointer to the path of the device to be
+ *               torn down
+ * Dependencies: The loop device must be enabled (CONFIG_DEV_LOOP=y)
+ */
+
+#define LOOPIOC_SETUP     _LOOPIOC(0x0001)
+#define LOOPIOC_TEARDOWN  _LOOPIOC(0x0002)
+
+#endif
+
+/****************************************************************************
+ * Type Definitions
+ ****************************************************************************/
+
+#ifdef CONFIG_DEV_LOOP
+/* This is the structure referred to in the argument to the LOOPIOC_SETUP
+ * IOCTL command.
+ */
+
+struct losetup_s
+{
+  FAR const char *devname;   /* The loop block device to be created */
+  FAR const char *filename;  /* The file or character device to use */
+  uint16_t sectsize;         /* The sector size to use with the block device */
+  off_t offset;              /* An offset that may be applied to the device */
+  bool readonly;             /* True: Read access will be supported only */
+};
+#endif
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+#ifdef __cplusplus
+#define EXTERN extern "C"
+extern "C"
+{
+#else
+#define EXTERN extern
+#endif
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: loop_register
+ *
+ * Description:
+ *   Register /dev/loop
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_DEV_LOOP
+void loop_register(void);
+#endif
+
+/****************************************************************************
+ * Name: losetup
+ *
+ * Description:
+ *   Setup the loop device so that it exports the file referenced by 'filename'
+ *   as a block device.
+ *
+ ****************************************************************************/
+
+int losetup(FAR const char *devname, FAR const char *filename,
+            uint16_t sectsize, off_t offset, bool readonly);
+
+/****************************************************************************
+ * Name: loteardown
+ *
+ * Description:
+ *   Undo the setup performed by losetup
+ *
+ ****************************************************************************/
+
+int loteardown(FAR const char *devname);
+
+#undef EXTERN
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __INCLUDE_NUTTX_FS_LOOP_H */