diff options
Diffstat (limited to 'nuttx/fs/fs_read.c')
-rw-r--r-- | nuttx/fs/fs_read.c | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/nuttx/fs/fs_read.c b/nuttx/fs/fs_read.c new file mode 100644 index 000000000..30dd4af03 --- /dev/null +++ b/nuttx/fs/fs_read.c @@ -0,0 +1,147 @@ +/**************************************************************************** + * fs_read.c + * + * Copyright (C) 2007-2009, 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 <sys/socket.h> + +#include <unistd.h> +#include <fcntl.h> +#include <sched.h> +#include <errno.h> + +#include "fs_internal.h" + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +#if CONFIG_NFILE_DESCRIPTORS > 0 +static inline ssize_t file_read(int fd, FAR void *buf, size_t nbytes) +{ + FAR struct filelist *list; + int ret = -EBADF; + + /* Get the thread-specific file list */ + + list = sched_getfiles(); + if (!list) + { + /* Failed to get the file list */ + + ret = -EMFILE; + } + + /* Were we given a valid file descriptor? */ + + else if ((unsigned int)fd < CONFIG_NFILE_DESCRIPTORS) + { + FAR struct file *this_file = &list->fl_files[fd]; + FAR struct inode *inode = this_file->f_inode; + + /* Yes.. Was this file opened for read access? */ + + if ((this_file->f_oflags & O_RDOK) == 0) + { + /* No.. File is not read-able */ + + ret = -EACCES; + } + + /* Is a driver or mountpoint registered? If so, does it support + * the read method? + */ + + else if (inode && inode->u.i_ops && inode->u.i_ops->read) + { + /* Yes.. then let it perform the read. NOTE that for the case + * of the mountpoint, we depend on the read methods bing + * identical in signature and position in the operations vtable. + */ + + ret = (int)inode->u.i_ops->read(this_file, (char*)buf, (size_t)nbytes); + } + } + + /* If an error occurred, set errno and return -1 (ERROR) */ + + if (ret < 0) + { + set_errno(-ret); + return ERROR; + } + + /* Otherwise, return the number of bytes read */ + + return ret; +} +#endif + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +ssize_t read(int fd, FAR void *buf, size_t nbytes) +{ + /* Did we get a valid file descriptor? */ + +#if CONFIG_NFILE_DESCRIPTORS > 0 + if ((unsigned int)fd >= CONFIG_NFILE_DESCRIPTORS) +#endif + { + /* No.. If networking is enabled, read() is the same as recv() with + * the flags parameter set to zero. + */ + +#if defined(CONFIG_NET) && CONFIG_NSOCKET_DESCRIPTORS > 0 + return recv(fd, buf, nbytes, 0); +#else + /* No networking... it is a bad descriptor in any event */ + + set_errno(EBADF); + return ERROR; +#endif + } + + /* The descriptor is in a valid range to file descriptor... do the read */ + +#if CONFIG_NFILE_DESCRIPTORS > 0 + return file_read(fd, buf, nbytes); +#endif +} |