/************************************************************
* fs_files.c
*
* Copyright (C) 2007 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* 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 Gregory Nutt 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 <string.h>
#include <semaphore.h>
#include <assert.h>
#include <sched.h>
#include <errno.h>
#include <nuttx/fs.h>
#include <nuttx/kmalloc.h>
#include "fs_internal.h"
/************************************************************
* Definitions
************************************************************/
/************************************************************
* Public Types
************************************************************/
/************************************************************
* Private Variables
************************************************************/
/************************************************************
* Private Variables
************************************************************/
/************************************************************
* Private Functions
************************************************************/
static void _files_semtake(FAR struct filelist *list)
{
/* Take the semaphore (perhaps waiting) */
while (sem_wait(&list->fl_sem) != 0)
{
/* The only case that an error should occr here is if
* the wait was awakened by a signal.
*/
ASSERT(*get_errno_ptr() == EINTR);
}
}
#define _files_semgive(list) sem_post(&list->fl_sem)
/************************************************************
* Pulblic Functions
************************************************************/
/* This is called from the FS initialization logic to configure
* the files.
*/
void files_initialize(void)
{
}
/* Allocate a list of files for a new task */
FAR struct filelist *files_alloclist(void)
{
FAR struct filelist *list;
list = (FAR struct filelist*)kzmalloc(sizeof(struct filelist));
if (list)
{
/* Start with a reference count of one */
list->fl_crefs = 1;
/* Initialize the list access mutex */
(void)sem_init(&list->fl_sem, 0, 1);
}
return list;
}
/* Increase the reference count on a file list */
int files_addreflist(FAR struct filelist *list)
{
if (list)
{
/* Increment the reference count on the list.
* NOTE: that we disable interrupts to do this
* (vs. taking the list semaphore). We do this
* because file cleanup operations often must be
* done from the IDLE task which cannot wait
* on semaphores.
*/
register irqstate_t flags = irqsave();
list->fl_crefs++;
irqrestore(flags);
}
return OK;
}
/* Release a reference to the file list */
int files_releaselist(FAR struct filelist *list)
{
int crefs;
if (list)
{
/* Decrement the reference count on the list.
* NOTE: that we disable interrupts to do this
* (vs. taking the list semaphore). We do this
* because file cleanup operations often must be
* done from the IDLE task which cannot wait
* on semaphores.
*/
register irqstate_t flags = irqsave();
crefs = --(list->fl_crefs);
irqrestore(flags);
/* If the count decrements to zero, then there is no reference
* to the structure and it should be deallocated. Since there
* are references, it would be an error if any task still held
* a reference to the list's semaphore.
*/
if (crefs <= 0)
{
int i;
/* close each file descriptor */
for (i = 0; i < CONFIG_NFILE_DESCRIPTORS; i++)
{
FAR struct inode *inode = list->fl_files[i].f_inode;
if (inode)
{
inode_release(inode);
}
}
/* Destroy the semaphore and release the filelist */
(void)sem_destroy(&list->fl_sem);
sched_free(list);
}
}
return OK;
}
/* Assign an inode to a specific files structure. this is the
* heart of dup2.
*/
int files_dup(FAR struct file *filep1, FAR struct file *filep2)
{
FAR struct filelist *list;
if (!filep1 || !filep1->f_inode || !filep2)
{
*get_errno_ptr() = EBADF;
return ERROR;
}
list = sched_getfiles();
if (!list)
{
*get_errno_ptr() = EMFILE;
return ERROR;
}
_files_semtake(list);
/* If there is already an inode contained in the new file structure,
* release it (effectively closing the file).
*/
if (filep2->f_inode)
{
inode_release(filep2->f_inode);
}
/* Increment the reference count on the contained inode */
inode_addref(filep1->f_inode);
/* Then clone the file structure */
filep2->f_oflags = filep1->f_oflags;
filep2->f_pos = filep1->f_pos;
filep2->f_inode = filep1->f_inode;
_files_semgive(list);
return OK;
}
/* Allocate a struct files instance and associate it with an
* inode instance. Returns the file descriptor == index into
* the files array.
*/
int files_allocate(FAR struct inode *inode, int oflags, off_t pos)
{
FAR struct filelist *list;
int i;
list = sched_getfiles();
if (list)
{
_files_semtake(list);
for (i = 0; i < CONFIG_NFILE_DESCRIPTORS; i++)
{
if (!list->fl_files[i].f_inode)
{
list->fl_files[i].f_oflags = oflags;
list->fl_files[i].f_pos = pos;
list->fl_files[i].f_inode = inode;
_files_semgive(list);
return i;
}
}
_files_semgive(list);
}
return ERROR;
}
void files_release(int filedes)
{
FAR struct filelist *list;
list = sched_getfiles();
if (list)
{
if (filedes >=0 && filedes < CONFIG_NFILE_DESCRIPTORS)
{
_files_semtake(list);
list->fl_files[filedes].f_oflags = 0;
list->fl_files[filedes].f_pos = 0;
list->fl_files[filedes].f_inode = NULL;
_files_semgive(list);
}
}
}
