diff options
Diffstat (limited to 'nuttx/fs/fs_fdopen.c')
| -rw-r--r-- | nuttx/fs/fs_fdopen.c | 261 |
1 files changed, 261 insertions, 0 deletions
diff --git a/nuttx/fs/fs_fdopen.c b/nuttx/fs/fs_fdopen.c new file mode 100644 index 000000000..ee6440bf5 --- /dev/null +++ b/nuttx/fs/fs_fdopen.c @@ -0,0 +1,261 @@ +/**************************************************************************** + * fs/fs_fdopen.c + * + * Copyright (C) 2007-2012 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 <stdio.h> +#include <string.h> +#include <semaphore.h> +#include <fcntl.h> +#include <errno.h> + +#include <nuttx/kmalloc.h> +#include <nuttx/fs/fs.h> +#include <nuttx/net/net.h> + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: fs_checkfd + * + * Description: + * Check if the file descriptor is valid for the provided TCB and if it + * supports the requested access. + * + ****************************************************************************/ + +#if CONFIG_NFILE_DESCRIPTORS > 0 +static inline int fs_checkfd(FAR _TCB *tcb, int fd, int oflags) +{ + FAR struct filelist *flist; + FAR struct inode *inode; + + /* Get the file list from the TCB */ + + flist = tcb->filelist; + + /* Get the inode associated with the file descriptor. This should + * normally be the case if fd >= 0. But not in the case where the + * called attempts to explictly stdin with fdopen(0) but stdin has + * been closed. + */ + + inode = flist->fl_files[fd].f_inode; + if (!inode) + { + /* No inode -- descriptor does not correspond to an open file */ + + return -ENOENT; + } + + /* Make sure that the inode supports the requested access. In + * the case of fdopen, we are not actually creating the file -- in + * particular w and w+ do not truncate the file and any files have + * already been created. + */ + + if (inode_checkflags(inode, oflags) != OK) + { + /* Cannot support the requested access */ + + return -EACCES; + } + + /* Looks good to me */ + + return OK; +} +#endif + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: fs_fdopen + * + * Description: + * This function does the core operations for fopen and fdopen. + * + ****************************************************************************/ + +FAR struct file_struct *fs_fdopen(int fd, int oflags, FAR _TCB *tcb) +{ + FAR struct streamlist *slist; + FAR FILE *stream; + int err = OK; + int ret; + int i; + + /* Check input parameters */ + + if (fd < 0) + { + err = EBADF; + goto errout; + } + + /* A NULL TCB pointer means to use this threads TCB. This is a little + * hack the let's this function be called from user-space (via a syscall) + * without having access to the TCB. + */ + + if (!tcb) + { + tcb = sched_self(); + } + + /* Verify that this is a valid file/socket descriptor and that the + * requested access can be support. + * + * Is this fd in the range of valid file descriptors? Socket descriptors + * lie in a different range. + */ + +#if CONFIG_NFILE_DESCRIPTORS > 0 + if ((unsigned int)fd >= CONFIG_NFILE_DESCRIPTORS) +#endif + { + /* No.. If networking is enabled then this might be a socket + * descriptor. + */ + +#if defined(CONFIG_NET) && CONFIG_NSOCKET_DESCRIPTORS > 0 + ret = net_checksd(fd, oflags); +#else + /* No networking... it is just a bad descriptor */ + + err = EBADF; + goto errout; +#endif + } + + /* The descriptor is in a valid range to file descriptor... perform some more checks */ + +#if CONFIG_NFILE_DESCRIPTORS > 0 + else + { + ret = fs_checkfd(tcb, fd, oflags); + } +#endif + + /* Do we have a good descriptor of some sort? */ + + if (ret < 0) + { + /* No... return the reported error */ + + err = -ret; + goto errout; + } + + /* Get the stream list from the TCB */ + + slist = tcb->streams; + + /* Find an unallocated FILE structure in the stream list */ + + ret = sem_wait(&slist->sl_sem); + if (ret != OK) + { + goto errout_with_errno; + } + + for (i = 0 ; i < CONFIG_NFILE_STREAMS; i++) + { + stream = &slist->sl_streams[i]; + if (stream->fs_filedes < 0) + { + /* Zero the structure */ + +#if CONFIG_STDIO_BUFFER_SIZE > 0 + memset(stream, 0, sizeof(FILE)); +#elif CONFIG_NUNGET_CHARS > 0 + stream->fs_nungotten = 0; +#endif + +#if CONFIG_STDIO_BUFFER_SIZE > 0 + /* Initialize the semaphore the manages access to the buffer */ + + (void)sem_init(&stream->fs_sem, 0, 1); + + /* Allocate the IO buffer */ + + stream->fs_bufstart = kmalloc(CONFIG_STDIO_BUFFER_SIZE); + if (!stream) + { + err = ENOMEM; + goto errout_with_sem; + } + + /* Set up pointers */ + + stream->fs_bufend = &stream->fs_bufstart[CONFIG_STDIO_BUFFER_SIZE]; + stream->fs_bufpos = stream->fs_bufstart; + stream->fs_bufpos = stream->fs_bufstart; + stream->fs_bufread = stream->fs_bufstart; +#endif + /* Save the file description and open flags. Setting the + * file descriptor locks this stream. + */ + + stream->fs_filedes = fd; + stream->fs_oflags = (uint16_t)oflags; + + sem_post(&slist->sl_sem); + return stream; + } + } + + /* No free stream available.. report ENFILE */ + + err = ENFILE; + +#if CONFIG_STDIO_BUFFER_SIZE > 0 +errout_with_sem: +#endif + sem_post(&slist->sl_sem); + +errout: + set_errno(err); +errout_with_errno: + return NULL; +} |