diff options
Diffstat (limited to 'nuttx/fs/nxffs/nxffs_open.c')
-rw-r--r-- | nuttx/fs/nxffs/nxffs_open.c | 521 |
1 files changed, 521 insertions, 0 deletions
diff --git a/nuttx/fs/nxffs/nxffs_open.c b/nuttx/fs/nxffs/nxffs_open.c new file mode 100644 index 000000000..a7caebca5 --- /dev/null +++ b/nuttx/fs/nxffs/nxffs_open.c @@ -0,0 +1,521 @@ +/**************************************************************************** + * fs/nxffs/nxffs_open.c + * + * Copyright (C) 2011 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt <spudmonkey@racsa.co.cr> + * + * References: Linux/Documentation/filesystems/romfs.txt + * + * 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 <string.h> +#include <fcntl.h> +#include <assert.h> +#include <errno.h> +#include <debug.h> + +#include <nuttx/kmalloc.h> +#include <nuttx/fs.h> +#include <nuttx/mtd.h> + +#include "nxffs.h" + +/**************************************************************************** + * Pre-processor Definitions + ****************************************************************************/ + +/**************************************************************************** + * Private Types + ****************************************************************************/ + +/**************************************************************************** + * Public Variables + ****************************************************************************/ + +/**************************************************************************** + * Private Variables + ****************************************************************************/ + +/* A singly-linked list of open files */ + +static struct nxffs_ofile_s *g_ofiles; + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: nxffs_create + * + * Description: + * Create a file: Verify the sufficient space exists at the end of the + * FLASH. If so, then write then update entry in preparation for writing. + * + ****************************************************************************/ + +static inline int nxffs_create(FAR struct nxffs_volume_s *volume, + FAR const char *name, mode_t mode, + FAR struct nxffs_ofile_s **ppofile) +{ +#warning "Check if too close to end of block for whole header" + return OK; +} + +/**************************************************************************** + * Name: nxffs_wropen + * + * Description: + * Handle opening for writing. Only a single writer is permitted and only + * file creation is supported. + * + ****************************************************************************/ + +static inline int nxffs_wropen(FAR struct nxffs_volume_s *volume, + FAR const char *name, mode_t mode, + FAR struct nxffs_ofile_s **ppofile) +{ + FAR struct nxffs_wrfile_s *wrfile; + FAR struct nxffs_entry_s entry; + int ret; + + /* Limitation: Only a single writer is permitted. Writing may involve + * extension of the file system in FLASH. Since files are contiguous + * in FLASH, only a single file may be extending the FLASH region. + */ + + if (volume->wrbusy) + { + fdbg("There is already a file writer\n"); + return -ENOSYS; + } + + /* Check if the file exists */ + + ret = nxffs_findinode(volume, name, &entry); + if (ret == OK) + { + /* It exists. It would be an error if we are asked to create it + * exclusively. + */ + + if ((mode & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL)) + { + fdbg("File exists, can't create O_EXCL\n"); + return -EEXIST; + } + + /* Were we asked to truncate the file? NOTE: Don't truncate the + * file if we were not also asked to created it. See below... + * we will not re-create the file unless O_CREAT is also specified. + */ + + else if ((mode & (O_CREAT|O_TRUNC)) == (O_CREAT|O_TRUNC)) + { + /* Just remove the file and fall through to re-create it */ +#warning "Should defer file removal until new file successfully written" + + ret = nxffs_rminode(volume, name); + if (ret < 0) + { + fdbg("nxffs_rminode failed: %d\n", -ret); + return ret; + } + } + + /* The file exists and we were not asked to truncate (and recreate) it. + * Limitation: Cannot write to existing files. + */ + + else + { + fdbg("File %s exists and we were not asked to truncate it\n"); + return -ENOSYS; + } + } + + /* Okay, the file is not open and does not exists (maybe because we deleted + * it). Now, make sure that we were asked to created it. + */ + + if ((mode & O_CREAT) == 0) + { + fdbg("Not asked to create the file\n"); + return -ENOENT; + } + + /* Yes.. Create a new structure that will describe the state of this open + * file. NOTE that a special variant of the open file structure is used + * that includes additional information to support the write operation. + */ + + wrfile = (FAR struct nxffs_wrfile_s *)kzalloc(sizeof(struct nxffs_wrfile_s)); + if (!wrfile) + { + return -ENOMEM; + } + + /* Initialize the open file state structure */ + + wrfile->ofile.crefs = 1; + + /* Allocate FLASH memory for the file and set up for the write */ + +#warning "Missing Logic" + + /* Add the open file structure to the head of the list of open files */ + + wrfile->ofile.flink = g_ofiles; + g_ofiles = &wrfile->ofile; + + /* Indicate that the volume is open for writing and return the open file + * instance. + */ + + volume->wrbusy = 1; + *ppofile = &wrfile->ofile; + return OK; +} + +/**************************************************************************** + * Name: nxffs_rdopen + * + * Description: + * Open an existing file for reading. + * + ****************************************************************************/ + +static inline int nxffs_rdopen(FAR struct nxffs_volume_s *volume, + FAR const char *name, + FAR struct nxffs_ofile_s **ppofile) +{ + FAR struct nxffs_ofile_s *ofile; + int ret; + + /* Check if the file has already been opened (for reading) */ + + ofile = nxffs_findofile(name); + if (ofile) + { + /* The file is already open. + * Limitation: Files cannot be open both for reading and writing. + */ + + if ((ofile->mode & O_WROK) != 0) + { + fdbg("File is open for writing\n"); + return -ENOSYS; + } + + /* Just increment the reference count on the ofile */ + + ofile->crefs++; + fdbg("crefs: %d\n", ofile->crefs); + } + + /* The file has not yet been opened. + * Limitation: The file must exist. We do not support creation of files + * read-only. + */ + + else + { + /* Not already open.. create a new open structure */ + + ofile = (FAR struct nxffs_ofile_s *)kzalloc(sizeof(struct nxffs_ofile_s)); + if (!ofile) + { + fdbg("ofile allocation failed\n"); + return -ENOMEM; + } + + /* Initialize the open file state structure */ + + ofile->crefs = 1; + + /* Find the file on this volume associated with this file name */ + + ret = nxffs_findinode(volume, name, &ofile->entry); + if (ret != OK) + { + fdbg("Inode '%s' not found: %d\n", name, -ret); + kfree(ofile); + return ret; + } + + /* Add the open file structure to the head of the list of open files */ + + ofile->flink = g_ofiles; + g_ofiles = ofile; + } + + /* Return the open file state structure */ + + *ppofile = ofile; + return OK; +} + +/**************************************************************************** + * Name: nxffs_freeofile + ****************************************************************************/ + +static inline void nxffs_freeofile(FAR struct nxffs_ofile_s *ofile) +{ + FAR struct nxffs_ofile_s *prev; + FAR struct nxffs_ofile_s *curr; + + /* Find the open file structure to be removed */ + + for (prev = NULL, curr = g_ofiles; + curr && curr != ofile; + prev = curr, curr = curr->flink); + + /* Was it found? */ + + if (curr) + { + /* Yes.. at the head of the list? */ + + if (prev) + { + prev->flink = ofile->flink; + } + else + { + g_ofiles = ofile->flink; + } + + /* Then free the open file */ + + nxffs_freeentry(&ofile->entry); + kfree(ofile); + } + else + { + fdbg("ERROR: Open inode %p not found\n", ofile); + } +} + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: nxffs_findofile + * + * Description: + * Search the list of already opened files to see if the inode of this + * name is one of the opened files. + * + * Input Parameters: + * name - The name of the inode to check. + * + * Returned Value: + * If an inode of this name is found in the list of opened inodes, then + * a reference to the open file structure is returned. NULL is returned + * otherwise. + * + ****************************************************************************/ + +FAR struct nxffs_ofile_s *nxffs_findofile(FAR const char *name) +{ + FAR struct nxffs_ofile_s *ofile; + + /* Check every open file. Note that the volume exclsem protects the + * list of open files. + */ + + for (ofile = g_ofiles; ofile; ofile = ofile->flink) + { + /* Check for a name match */ + + if (strcmp(name, ofile->entry.name) == 0) + { + return ofile; + } + } + + return NULL; +} + +/**************************************************************************** + * Name: nxffs_open + * + * Description: + * This is the standard mountpoint open method. + * + ****************************************************************************/ + +int nxffs_open(FAR struct file *filep, FAR const char *relpath, + int oflags, mode_t mode) +{ + FAR struct nxffs_volume_s *volume; + FAR struct nxffs_ofile_s *ofile = NULL; + int ret; + + fvdbg("Open '%s'\n", relpath); + + /* Sanity checks */ + + DEBUGASSERT(filep->f_priv == NULL && filep->f_inode != NULL); + + /* Get the mountpoint private data from the NuttX inode reference in the + * file structure + */ + + volume = (FAR struct nxffs_volume_s*)filep->f_inode->i_private; + DEBUGASSERT(volume != NULL); + + /* Get exclusive access to the volume. Note that the volume exclsem + * protects the open file list. + */ + + ret = sem_wait(&volume->exclsem); + if (ret != OK) + { + ret = -errno; + fdbg("sem_wait failed: %d\n", ret); + goto errout; + } + +#ifdef CONFIG_FILE_MODE +# warning "Missing check for privileges based on inode->i_mode" +#endif + + /* Limitation: A file must be opened for reading or writing, but not both. + * There is no general for extending the size of of a file. Extending the + * file size of possible if the file to be extended is the last in the + * sequence on FLASH, but since that case is not the general case, no file + * extension is supported. + */ + + switch (mode & (O_WROK|O_RDOK)) + { + case 0: + default: + fdbg("One of O_WRONLY/O_RDONLY must be provided\n"); + ret = -EINVAL; + goto errout_with_semaphore; + + case O_WROK: + ret = nxffs_wropen(volume, relpath, mode, &ofile); + break; + + case O_RDOK: + ret = nxffs_rdopen(volume, relpath, &ofile); + break; + + case O_WROK|O_RDOK: + fdbg("O_RDWR is not supported\n"); + ret = -ENOSYS; + goto errout_with_semaphore; + } + + /* Save open-specific state in filep->f_priv */ + + filep->f_priv = ofile; + ret = OK; + +errout_with_semaphore: + sem_post(&volume->exclsem); +errout: + return ret; +} + +/**************************************************************************** + * Name: nxffs_close + * + * Description: + * This is the standard mountpoint close method. + * + ****************************************************************************/ + +int nxffs_close(FAR struct file *filep) +{ + FAR struct nxffs_volume_s *volume; + FAR struct nxffs_ofile_s *ofile; + int ret = -ENOSYS; + + fvdbg("Closing\n"); + + /* Sanity checks */ + + DEBUGASSERT(filep->f_priv != NULL && filep->f_inode != NULL); + + /* Recover the open file state from the struct file instance */ + + ofile = (FAR struct nxffs_ofile_s *)filep->f_priv; + + /* Recover the volume state from the open file */ + + volume = (FAR struct nxffs_volume_s *)filep->f_inode->i_private; + DEBUGASSERT(volume != NULL); + + /* Get exclusive access to the volume. Note that the volume exclsem + * protects the open file list. + */ + + ret = sem_wait(&volume->exclsem); + if (ret != OK) + { + ret = -errno; + fdbg("sem_wait failed: %d\n", ret); + goto errout; + } + + /* Decrement the reference count on the open file */ + + if (ofile->crefs == 1) + { + /* Decrementing the reference count would take it zero. Time to + * delete the open file state. + */ + + nxffs_freeofile(ofile); + } + else + { + /* Just decrement the reference count */ + + ofile->crefs--; + } + + filep->f_priv = NULL; + ret = OK; + + sem_post(&volume->exclsem); +errout: + return ret; +} |