Re: ftruncate function for eCos FAT filesystem

[Gratian Crisan <nelu at iv dot ro>]

Hi,

Indeed the support for truncate is missing from POSIX layer so right now 
I'm calling it directly from a truncate function I've wrote but is 
rather hack'is (see the attached file).

-Nelu

Andrew Lunn wrote:

> On Mon, Sep 05, 2005 at 03:21:03PM +0300, Gratian Crisan wrote:
>  
>
> > Hi,
> >
> > attached is a patch for a ftruncate function implementation for the eCos 
> > FAT filesystem. If it's useful to anybody please feel free to use it.
> >    
>
> How do you call this function? There does not appear to be any support
> for ftruncate() or truncate() in the layers above the filesystem.
>
>        Thanks
>                Andrew
>
>  

#include <cyg/infra/cyg_type.h>

#include <stddef.h>             // NULL, size_t
#include <unistd.h>
#include <limits.h>
#include <sys/types.h>
#include <errno.h>

#include <cyg/fileio/fileio.h>

__externC cyg_file *cyg_fp_get( int fd );
__externC void cyg_fp_free( cyg_file *fp );

__externC void cyg_file_lock( cyg_file *fp, cyg_uint32 syncmode );
__externC void cyg_file_unlock( cyg_file *fp, cyg_uint32 syncmode );

int fatfs_fo_ftruncate(struct CYG_FILE_TAG *fp, off_t length);

int ftruncate(int fd, off_t length)
{
	cyg_file *fp;
	
	fp = cyg_fp_get(fd);

	if( fp == NULL ) {
		errno = EBADF;
		return -1;
	}
	
	cyg_file_lock(fp, fp->f_syncmode);
	errno = fatfs_fo_ftruncate(fp, length);
	cyg_file_unlock(fp, fp->f_syncmode);

	cyg_fp_free( fp );

	if (ENOERR == errno) {
		return 0;
	} else {
		return -1;
	}
}