diff options
Diffstat (limited to 'nuttx/fs/nxffs/nxffs_read.c')
-rw-r--r-- | nuttx/fs/nxffs/nxffs_read.c | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/nuttx/fs/nxffs/nxffs_read.c b/nuttx/fs/nxffs/nxffs_read.c new file mode 100644 index 000000000..d8c2e9567 --- /dev/null +++ b/nuttx/fs/nxffs/nxffs_read.c @@ -0,0 +1,174 @@ +/**************************************************************************** + * fs/nxffs/nxffs_read.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/fs.h> +#include <nuttx/mtd.h> + +#include "nxffs.h" + +/**************************************************************************** + * Pre-processor Definitions + ****************************************************************************/ + +/**************************************************************************** + * Public Types + ****************************************************************************/ + +/**************************************************************************** + * Public Variables + ****************************************************************************/ + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: nxffs_rdseek + * + * Description: + * Seek to the file position before read or write access. Note that the + * simplier nxffs_ioseek() cannot be used for this purpose. File offsets + * are not easily mapped to FLASH offsets due to intervening block and + * data headers. + * + * Input Parameters: + * volume - Describes the current volume + * entry - Describes the open inode + * fpos - The desired file position + * + ****************************************************************************/ + +static ssize_t nxffs_rdseek(FAR struct nxffs_volume_s *volume, + FAR struct nxffs_entry_s *entry, + off_t fpos) +{ +#warning "Missing Logic" + return 0; +} + +/**************************************************************************** + * Public Functions + ****************************************************************************/ +/**************************************************************************** + * Name: nxffs_read + * + * Description: + * This is an implementation of the NuttX standard file system read + * method. + * + ****************************************************************************/ + +ssize_t nxffs_read(FAR struct file *filep, FAR char *buffer, size_t buflen) +{ + FAR struct nxffs_volume_s *volume; + FAR struct nxffs_ofile_s *ofile; + ssize_t ret; + + fvdbg("Read %d bytes from offset %d\n", buflen, filep->f_pos); + + /* 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; + } + + /* Check if the file was opened with read access */ + + if ((ofile->mode & O_RDOK) == 0) + { + fdbg("File not open for read access\n"); + ret = -EACCES; + goto errout_with_semaphore; + } + + /* Seek to the current file offset */ + + ret = nxffs_rdseek(volume, &ofile->entry, filep->f_pos); + if (ret < 0) + { + fdbg("nxffs_fwseek failed: %d\n", -ret); + ret = -EACCES; + goto errout_with_semaphore; + } + + /* Read data from that file offset */ + + ret = nxffs_rddata(volume, (FAR uint8_t *)buffer, buflen); + if (ret > 0) + { + /* Update the file offset */ + + filep->f_pos += ret; + } + +errout_with_semaphore: + sem_post(&volume->exclsem); +errout: + return ret; +} + |