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Diffstat (limited to 'nuttx/fs/fs_files.c')
-rw-r--r-- | nuttx/fs/fs_files.c | 479 |
1 files changed, 479 insertions, 0 deletions
diff --git a/nuttx/fs/fs_files.c b/nuttx/fs/fs_files.c new file mode 100644 index 000000000..033cd8c63 --- /dev/null +++ b/nuttx/fs/fs_files.c @@ -0,0 +1,479 @@ +/**************************************************************************** + * fs/fs_files.c + * + * Copyright (C) 2007-2009, 2011-2012 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 <string.h> +#include <semaphore.h> +#include <assert.h> +#include <sched.h> +#include <errno.h> + +#include <nuttx/fs/fs.h> +#include <nuttx/kmalloc.h> + +#include "fs_internal.h" + +/**************************************************************************** + * Pre-processor Definitions + ****************************************************************************/ + +/**************************************************************************** + * Private Types + ****************************************************************************/ + +/**************************************************************************** + * Private Variables + ****************************************************************************/ + +/**************************************************************************** + * Private Variables + ****************************************************************************/ + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: _files_semtake + ****************************************************************************/ + +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() == EINTR); + } +} + +/**************************************************************************** + * Name: _files_semgive + ****************************************************************************/ + +#define _files_semgive(list) sem_post(&list->fl_sem) + +/**************************************************************************** + * Name: _files_close + * + * Description: + * Close an inode (if open) + * + * Assumuptions: + * Caller holds the list semaphore because the file descriptor will be freed. + * + ****************************************************************************/ + +static int _files_close(FAR struct file *filep) +{ + struct inode *inode = filep->f_inode; + int ret = OK; + + /* Check if the struct file is open (i.e., assigned an inode) */ + + if (inode) + { + /* Close the file, driver, or mountpoint. */ + + if (inode->u.i_ops && inode->u.i_ops->close) + { + /* Perform the close operation */ + + ret = inode->u.i_ops->close(filep); + } + + /* And release the inode */ + + inode_release(inode); + + /* Release the file descriptor */ + + filep->f_oflags = 0; + filep->f_pos = 0; + filep->f_inode = NULL; + } + + return ret; +} + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: files_initialize + * + * Description: + * This is called from the FS initialization logic to configure the files. + * + ****************************************************************************/ + +void files_initialize(void) +{ +} + +/**************************************************************************** + * Name: files_alloclist + * + * Description: Allocate a list of files for a new task + * + ****************************************************************************/ + +FAR struct filelist *files_alloclist(void) +{ + FAR struct filelist *list; + list = (FAR struct filelist*)kzalloc(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; +} + +/**************************************************************************** + * Name: files_addreflist + * + * Description: + * 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; +} + +/**************************************************************************** + * Name: files_releaselist + * + * Description: + * 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 .. Normally, you would need + * take the list semaphore, but it is safe to ignore the + * semaphore in this context because there are no references + */ + + for (i = 0; i < CONFIG_NFILE_DESCRIPTORS; i++) + { + (void)_files_close(&list->fl_files[i]); + } + + /* Destroy the semaphore and release the filelist */ + + (void)sem_destroy(&list->fl_sem); + sched_free(list); + } + } + + return OK; +} + +/**************************************************************************** + * Name: files_dup + * + * Description: + * 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; + FAR struct inode *inode; + int err; + int ret; + + if (!filep1 || !filep1->f_inode || !filep2) + { + err = EBADF; + goto errout; + } + +#ifndef CONFIG_DISABLE_MOUNTPOINT + if (INODE_IS_MOUNTPT(filep1->f_inode)) + { + err = ENOSYS; /* Not yet supported */ + goto errout; + } +#endif + + list = sched_getfiles(); + if (!list) + { + err = EMFILE; + goto errout; + } + + _files_semtake(list); + + /* If there is already an inode contained in the new file structure, + * close the file and release the inode. + */ + + ret = _files_close(filep2); + if (ret < 0) + { + /* An error occurred while closing the driver */ + + goto errout_with_ret; + } + + /* Increment the reference count on the contained inode */ + + inode = filep1->f_inode; + inode_addref(inode); + + /* Then clone the file structure */ + + filep2->f_oflags = filep1->f_oflags; + filep2->f_pos = filep1->f_pos; + filep2->f_inode = inode; + + /* Call the open method on the file, driver, mountpoint so that it + * can maintain the correct open counts. + */ + + if (inode->u.i_ops && inode->u.i_ops->open) + { +#ifndef CONFIG_DISABLE_MOUNTPOINT +#if 0 /* Not implemented */ + if (INODE_IS_MOUNTPT(inode)) + { + /* Open a file on the mountpoint */ + + ret = inode->u.i_mops->open(filep2, ?, filep2->f_oflags, ?); + } + else +#endif +#endif + { + /* Open the psuedo file or device driver */ + + ret = inode->u.i_ops->open(filep2); + } + + /* Handle open failures */ + + if (ret < 0) + { + goto errout_with_inode; + } + } + + _files_semgive(list); + return OK; + +/* Handler various error conditions */ + +errout_with_inode: + inode_release(filep2->f_inode); + filep2->f_oflags = 0; + filep2->f_pos = 0; + filep2->f_inode = NULL; + +errout_with_ret: + err = -ret; + _files_semgive(list); + +errout: + set_errno(err); + return ERROR; +} + +/**************************************************************************** + * Name: files_allocate + * + * Description: + * 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, int minfd) +{ + FAR struct filelist *list; + int i; + + list = sched_getfiles(); + if (list) + { + _files_semtake(list); + for (i = minfd; 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; +} + +/**************************************************************************** + * Name: files_close + * + * Description: + * Close an inode (if open) + * + * Assumuptions: + * Caller holds the list semaphore because the file descriptor will be freed. + * + ****************************************************************************/ + +int files_close(int filedes) +{ + FAR struct filelist *list; + int ret; + + /* Get the thread-specific file list */ + + list = sched_getfiles(); + if (!list) + { + return -EMFILE; + } + + /* If the file was properly opened, there should be an inode assigned */ + + if (filedes < 0 || filedes >= CONFIG_NFILE_DESCRIPTORS || !list->fl_files[filedes].f_inode) + { + return -EBADF; + } + + /* Perform the protected close operation */ + + _files_semtake(list); + ret = _files_close(&list->fl_files[filedes]); + _files_semgive(list); + return ret; +} + +/**************************************************************************** + * Name: files_release + * + * Assumuptions: + * Similar to files_close(). Called only from open() logic on error + * conditions. + * + ****************************************************************************/ + +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); + } + } +} + |