b08a86171f
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3 42af7a65-404d-4744-a932-0658087f49c3
274 lines
7.0 KiB
C
274 lines
7.0 KiB
C
/************************************************************
|
|
* 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>
|
|
|
|
|
|
#if CONFIG_NFILE_DESCRIPTORS >0
|
|
|
|
#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(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);
|
|
}
|
|
}
|
|
|
|
static inline void _files_semgive(struct filelist *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 */
|
|
|
|
struct filelist *files_alloclist(void)
|
|
{
|
|
struct filelist *list;
|
|
list = (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(struct filelist *list)
|
|
{
|
|
if (list)
|
|
{
|
|
/* Increment the reference count on the list */
|
|
|
|
_files_semtake(list);
|
|
list->fl_crefs++;
|
|
_files_semgive(list);
|
|
}
|
|
return OK;
|
|
}
|
|
|
|
/* Release a reference to the file list */
|
|
|
|
int files_releaselist(struct filelist *list)
|
|
{
|
|
int crefs;
|
|
if (list)
|
|
{
|
|
/* Decrement the reference count */
|
|
|
|
_files_semtake(list);
|
|
crefs = --list->fl_crefs;
|
|
_files_semgive(list);
|
|
|
|
/* If the count decrements to zero, then there is no reference
|
|
* to the structure and it should be deallocated.
|
|
*/
|
|
|
|
if (crefs <= 0)
|
|
{
|
|
int i;
|
|
|
|
/* close each file descriptor */
|
|
|
|
for (i = 0; i < CONFIG_NFILE_DESCRIPTORS; i++)
|
|
{
|
|
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(struct file *filep1, struct file *filep2)
|
|
{
|
|
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(struct inode *inode, int oflags, off_t pos)
|
|
{
|
|
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)
|
|
{
|
|
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);
|
|
}
|
|
}
|
|
}
|
|
#endif /* CONFIG_NFILE_DESCRIPTORS */
|