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147 lines
4.6 KiB
147 lines
4.6 KiB
/**************************************************************************** |
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* fs_read.c |
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* |
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* Copyright (C) 2007-2009, 2012 Gregory Nutt. All rights reserved. |
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* Author: Gregory Nutt <gnutt@nuttx.org> |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in |
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* the documentation and/or other materials provided with the |
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* distribution. |
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* 3. Neither the name NuttX nor the names of its contributors may be |
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* used to endorse or promote products derived from this software |
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* without specific prior written permission. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS |
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED |
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN |
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
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* POSSIBILITY OF SUCH DAMAGE. |
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* |
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****************************************************************************/ |
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/**************************************************************************** |
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* Included Files |
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****************************************************************************/ |
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#include <nuttx/config.h> |
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#include <sys/types.h> |
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#include <sys/socket.h> |
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#include <unistd.h> |
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#include <fcntl.h> |
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#include <sched.h> |
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#include <errno.h> |
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#include "fs_internal.h" |
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/**************************************************************************** |
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* Private Functions |
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****************************************************************************/ |
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#if CONFIG_NFILE_DESCRIPTORS > 0 |
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static inline ssize_t file_read(int fd, FAR void *buf, size_t nbytes) |
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{ |
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FAR struct filelist *list; |
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int ret = -EBADF; |
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/* Get the thread-specific file list */ |
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list = sched_getfiles(); |
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if (!list) |
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{ |
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/* Failed to get the file list */ |
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ret = -EMFILE; |
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} |
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/* Were we given a valid file descriptor? */ |
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else if ((unsigned int)fd < CONFIG_NFILE_DESCRIPTORS) |
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{ |
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FAR struct file *this_file = &list->fl_files[fd]; |
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FAR struct inode *inode = this_file->f_inode; |
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/* Yes.. Was this file opened for read access? */ |
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if ((this_file->f_oflags & O_RDOK) == 0) |
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{ |
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/* No.. File is not read-able */ |
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ret = -EACCES; |
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} |
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/* Is a driver or mountpoint registered? If so, does it support |
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* the read method? |
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*/ |
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else if (inode && inode->u.i_ops && inode->u.i_ops->read) |
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{ |
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/* Yes.. then let it perform the read. NOTE that for the case |
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* of the mountpoint, we depend on the read methods bing |
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* identical in signature and position in the operations vtable. |
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*/ |
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ret = (int)inode->u.i_ops->read(this_file, (char*)buf, (size_t)nbytes); |
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} |
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} |
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/* If an error occurred, set errno and return -1 (ERROR) */ |
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if (ret < 0) |
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{ |
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set_errno(-ret); |
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return ERROR; |
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} |
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/* Otherwise, return the number of bytes read */ |
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return ret; |
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} |
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#endif |
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/**************************************************************************** |
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* Public Functions |
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****************************************************************************/ |
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ssize_t read(int fd, FAR void *buf, size_t nbytes) |
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{ |
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/* Did we get a valid file descriptor? */ |
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#if CONFIG_NFILE_DESCRIPTORS > 0 |
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if ((unsigned int)fd >= CONFIG_NFILE_DESCRIPTORS) |
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#endif |
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{ |
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/* No.. If networking is enabled, read() is the same as recv() with |
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* the flags parameter set to zero. |
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*/ |
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#if defined(CONFIG_NET) && CONFIG_NSOCKET_DESCRIPTORS > 0 |
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return recv(fd, buf, nbytes, 0); |
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#else |
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/* No networking... it is a bad descriptor in any event */ |
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set_errno(EBADF); |
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return ERROR; |
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#endif |
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} |
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/* The descriptor is in a valid range to file descriptor... do the read */ |
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#if CONFIG_NFILE_DESCRIPTORS > 0 |
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return file_read(fd, buf, nbytes); |
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#endif |
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}
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