getcwd syscall fails on 3rd subfolder

[Hoefle Marco]

Hello Chris,
The root is IMFS and the FAT12 partition is mounted to /mnt
Let me explain how the fatfs image is linked to the application:

1) a fat12 image is generated using:
 /sbin/mkfs.vfat -F 12 -S 512 -s 1 -r 512 -f 1 -v fs_image

2) the image is initialized with default folders/files: 
mcopy -b/ -i fs_image) content/* ::/

3) a C array is generated using:
xxd -i fs_image > fs_image.c 

4) This large C file is compiled and linked into the RTEMS application.

I wanted to use a FAT32 image first but that didn't work at all. RTEMS
mount was successful but the mounted disk was empty.
Could it be that the image generated with mkfs.vfat is not compatible
with the RTEMS dosfs implementation?



This is how the FAT12 disk is mounted:


extern unsigned int fatfs_image_len;
extern unsigned char fatfs_image[];

/**
* The RAM Disk configuration.
*/
rtems_ramdisk_config rtems_ramdisk_configuration[] =
{
		{
				.block_size = 512,
				.location = fatfs_image
		}
};


/**
* The number of RAM Disk configurations.
*/
size_t rtems_ramdisk_configuration_size = 1;

/**
* Create the RAM Disk Driver entry.
*/
rtems_driver_address_table rtems_ramdisk_io_ops = {
		initialization_entry: ramdisk_initialize,
		open_entry: rtems_blkdev_generic_open,
		close_entry: rtems_blkdev_generic_close,
		read_entry: rtems_blkdev_generic_read,
		write_entry: rtems_blkdev_generic_write,
		control_entry: rtems_blkdev_generic_ioctl
};


static int setup_ramdisk (const char* mntpath)
{
	rtems_device_major_number major;
	rtems_status_code sc;

	rtems_ramdisk_configuration[0].block_num =
			fatfs_image_len /
rtems_ramdisk_configuration[0].block_size;

	sc = rtems_io_register_driver (
			RTEMS_DRIVER_AUTO_MAJOR,
			&rtems_ramdisk_io_ops,
			&major);

	if (sc != RTEMS_SUCCESSFUL) {
		nts_printf ("error: ramdisk driver not initialised:
%s\n",
				rtems_status_text (sc));

		return NTS_FAILURE;
	}

	nts_printf ("RAM Disk registered\n");

	mkdir(mntpath, 0777);

	sc = mount("/dev/rda", mntpath, "dosfs",
RTEMS_FILESYSTEM_READ_WRITE, NULL);
	nts_printf("mount return: %d\n", sc);

	nts_printf("ram disk addr: 0x%08x\n", (unsigned int)
(rtems_ramdisk_configuration[0].location));

	return NTS_OK;
}





-----Original Message-----
From: Chris Johns [mailto:chrisj at rtems.org] 
Sent: Mittwoch, 9. April 2014 03:06
To: Hoefle Marco; rtems-users at rtems.org
Subject: Re: getcwd syscall fails on 3rd subfolder

On 8/04/2014 10:22 pm, Hoefle Marco wrote:
>> Hello,
>> we use the Gaisler RTEMS Kernel 4-10-1.2.14 on a GR712RC board.

>I have not used their version or hardware.

>> The following function is used to  determine the current working
>> directory on a fatfs:
>>
>>
>> static NtsError fs_pwd_do( int argc, char **argv)
>> {
>>          char *ret = getcwd(NULL, 0);
>>          if(ret) {
>>                  nts_printf("%s\n", ret);
>>                  free(ret);
>>                  return NTS_OK;
>>          }
>>
>>          nts_printf("getcwd failed, errno: %d, MAXPATHLEN: %d\n",
errno,
>> MAXPATHLEN);
>>          return NTS_FAILURE;
>> }
>>
>>
>> The fatfs was generated using:
>>          @dd if=/dev/zero of=$(NAME) bs=256 count=1024 > /dev/null
>          /sbin/mkfs.vfat -F 12 -S 512 -s 1 -r 512 -f 1 -v $(NAME)
>
>
> This is what happens:
>
> cassis> fs mount
> RAM Disk registered
> mount return: 0
> ram disk addr: 0x64000000

This would seem to be a root disk. Is this an IMFS disk or a RAM disk ?

> cassis> fs ls
> 3920 dev
> 16384 mnt
> cassis> fs pwd
> /
> cassis> fs cwd mnt
> changed to mnt
> cassis> fs pwd
> /mnt
> cassis> fs ls
> 512 template
> cassis> fs cwd template
> changed to template
> cassis> fs pwd
> /mnt/template
> cassis>
> cassis> fs ls
> 512 .
> 16384 ..
> 512 param
> 512 logs
> cassis> fs cwd logs
> changed to logs
> cassis> fs pwd
> getcwd failed, errno: 2, MAXPATHLEN: 1024

The getcwd code looks up the path to the parent until the root to build 
the path. There maybe something wrong here if the root is not IMFS.

Chris

> cassis>
>
>
> The folder logs is definitely existing:
> cassis> fs dump /mnt/template/logs/housekeeping/log0
> file size: 10
> 64 61 63 30 3a 20 31 30 30 0a
>
> A non existing file leeds to:
> cassis> fs dump /mnt/template/logs/housekeeping/log9
> file size: 10
> failure, ret: -1, errno: 2
>
> Has anybody an idea why getcwd() fails (errno 2 means not existent)?
>
> Cheers,
> Marco
>
>
>
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