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

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This commit is contained in:
Gregory Nutt 2015-11-25 17:13:56 -06:00
parent b84da6e696
commit ed35eb0f8d
11 changed files with 342 additions and 46 deletions
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4
ChangeLog
View file

@ -11159,3 +11159,7 @@
convert a regular file (or driver file) to an MTD device. This is
useful for testing on the simulation using the hostfs. From Ken
Petit (2015-11-25).
* drivers/loop: Add a loop character device. losetup() and
loteardown() should not be called directory from applications.
Rather, these functions are now available as IOCTL commands to the
loop driver (2015-11-25).

17
TODO
View file

@ -439,7 +439,6 @@ o Kernel/Protected Build
COMMAND KERNEL INTERFACE(s)
-------- ----------------------------------------------
losetup losetup(), loteardown()
mkfatfs mkfatfs
mkrd ramdisk_register()
ps sched_foreach()
@ -454,22 +453,6 @@ o Kernel/Protected Build
http://git.busybox.net/busybox/tree/util-linux/mkfs_vfat.c
Here is how the Busybox/Linux losetup works:
This is the busybox losetup():
http://git.busybox.net/busybox/tree/util-linux/losetup.c .
You can see that it relies on query_loop(), set_loop(), and
del_loop() to do the really work. query_loop() and friends
are here:
http://git.busybox.net/busybox/tree/libbb/loop.c.
They each open a device and interface with it using ioctl calls.
That is probably how NuttX should do things as well. But that
is pretty much a redesign.
Status: Open
Priority: Medium/High -- the kernel build configuration is not fully fielded
yet.

2
arch

@ -1 +1 @@
Subproject commit 6fa995b0aac7816b4250c41a737309417f6e2d1e
Subproject commit 994be48b7dfe1dffd1fa9fdfa8dd1468bf5d7b7b

2
configs

@ -1 +1 @@
Subproject commit bf0c88329540d1e674e0c2bfeee2350e7898c5b5
Subproject commit 931d2ed27909e6265eb2eefae1346b758c37a739

2
drivers/loop/Kconfig
View file

@ -3,7 +3,7 @@
# see the file kconfig-language.txt in the NuttX tools repository.
#
config LOOP
config EEV_LOOP
bool "Enable loop device"
default n
---help---

4
drivers/loop/Make.defs
View file

@ -39,8 +39,8 @@ ifneq ($(CONFIG_DISABLE_MOUNTPOINT),y)
# Include loop device support
ifneq ($(CONFIG_LOOP),y)
# CSRCS += loop.c
ifeq ($(CONFIG_DEV_LOOP),y)
CSRCS += loop.c
endif
CSRCS += losetup.c

179
drivers/loop/loop.c Normal file
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@ -0,0 +1,179 @@
/****************************************************************************
* drivers/loop/loop.c
*
* 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdbool.h>
#include <string.h>
#include <errno.h>
#include <nuttx/fs/fs.h>
#include <nuttx/fs/loop.h>
#ifdef CONFIG_DEV_LOOP
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
static ssize_t loop_read(FAR struct file *filep, FAR char *buffer,
size_t buflen);
static ssize_t loop_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen);
static int loop_ioctl(FAR struct file *filep, int cmd, unsigned long arg);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct file_operations loop_fops =
{
0, /* open */
0, /* close */
loop_read, /* read */
loop_write, /* write */
0, /* seek */
loop_ioctl /* ioctl */
#ifndef CONFIG_DISABLE_POLL
, 0 /* poll */
#endif
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: loop_read
****************************************************************************/
static ssize_t loop_read(FAR struct file *filep, FAR char *buffer, size_t len)
{
return 0; /* Return EOF */
}
/****************************************************************************
* Name: loop_write
****************************************************************************/
static ssize_t loop_write(FAR struct file *filep, FAR const char *buffer, size_t len)
{
return len; /* Say that everything was written */
}
/****************************************************************************
* Name: loop_ioctl
****************************************************************************/
static int loop_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
{
int ret;
switch (cmd)
{
/* 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)
*/
case LOOPIOC_SETUP:
{
FAR struct losetup_s *setup = (FAR struct losetup_s *)((uintptr_t)arg);
if (setup == NULL)
{
ret = -EINVAL;
}
else
{
ret = losetup(setup->devname, setup->filename, setup->sectsize,
setup->offset, setup->readonly);
}
}
break;
/* 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)
*/
case LOOPIOC_TEARDOWN:
{
FAR const char *devname = (FAR const char *)((uintptr_t)arg);
if (devname == NULL)
{
ret = -EINVAL;
}
else
{
ret = loteardown(devname);
}
}
break;
default:
ret = -ENOTTY;
}
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: loop_register
*
* Description:
* Register /dev/null
*
****************************************************************************/
void loop_register(void)
{
(void)register_driver("/dev/loop", &loop_fops, 0666, NULL);
}
#endif /* CONFIG_DEV_LOOP */

3
drivers/loop/losetup.c
View file

@ -1,5 +1,5 @@
/****************************************************************************
* drivers/losetup.c
* drivers/loop/losetup.c
*
* Copyright (C) 2008-2009, 2011, 2014-2015 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
@ -58,6 +58,7 @@
#include <nuttx/kmalloc.h>
#include <nuttx/fs/fs.h>
#include <nuttx/fs/loop.h>
/****************************************************************************
* Pre-processor Definitions

23
include/nuttx/fs/fs.h
View file

@ -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

7
include/nuttx/fs/ioctl.h
View file

@ -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)

145
include/nuttx/fs/loop.h Normal file
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@ -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 */