px4-firmware/nuttx/fs/fs_fcntl.c

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/****************************************************************************
* fs/fs_fcntl.c
*
* Copyright (C) 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 <stdarg.h>
#include <fcntl.h>
#include <errno.h>
#include <nuttx/fs/fs.h>
#include <nuttx/net/net.h>
#include <nuttx/sched.h>
#include "fs_internal.h"
/****************************************************************************
* Private Functions
****************************************************************************/
#if CONFIG_NFILE_DESCRIPTORS > 0
static inline int file_vfcntl(int fildes, int cmd, va_list ap)
{
FAR struct filelist *list;
FAR struct file *this_file;
int err = 0;
int ret = OK;
/* Get the thread-specific file list */
list = sched_getfiles();
if (!list)
{
err = EMFILE;
goto errout;
}
/* Was this file opened ? */
this_file = &list->fl_files[fildes];
if (!this_file->f_inode)
{
err = EBADF;
goto errout;
}
switch (cmd)
{
case F_DUPFD:
/* Return a new file descriptor which shall be the lowest numbered
* available (that is, not already open) file descriptor greater than
* or equal to the third argument, arg, taken as an integer of type
* int. The new file descriptor shall refer to the same open file
* description as the original file descriptor, and shall share any
* locks. The FD_CLOEXEC flag associated with the new file descriptor
* shall be cleared to keep the file open across calls to one of the
* exec functions.
*/
{
ret = file_dup(fildes, va_arg(ap, int));
}
break;
case F_GETFD:
/* Get the file descriptor flags defined in <fcntl.h> that are associated
* with the file descriptor fildes. File descriptor flags are associated
* with a single file descriptor and do not affect other file descriptors
* that refer to the same file.
*/
case F_SETFD:
/* Set the file descriptor flags defined in <fcntl.h>, that are associated
* with fildes, to the third argument, arg, taken as type int. If the
* FD_CLOEXEC flag in the third argument is 0, the file shall remain open
* across the exec functions; otherwise, the file shall be closed upon
* successful execution of one of the exec functions.
*/
err = ENOSYS;
break;
case F_GETFL:
/* Get the file status flags and file access modes, defined in <fcntl.h>,
* for the file description associated with fildes. The file access modes
* can be extracted from the return value using the mask O_ACCMODE, which is
* defined in <fcntl.h>. File status flags and file access modes are associated
* with the file description and do not affect other file descriptors that
* refer to the same file with different open file descriptions.
*/
{
ret = this_file->f_oflags;
}
break;
case F_SETFL:
/* Set the file status flags, defined in <fcntl.h>, for the file description
* associated with fildes from the corresponding bits in the third argument,
* arg, taken as type int. Bits corresponding to the file access mode and
* the file creation flags, as defined in <fcntl.h>, that are set in arg shall
* be ignored. If any bits in arg other than those mentioned here are changed
* by the application, the result is unspecified.
*/
{
this_file->f_oflags = va_arg(ap, int);
}
break;
case F_GETOWN:
/* If fildes refers to a socket, get the process or process group ID specified
* to receive SIGURG signals when out-of-band data is available. Positive values
* indicate a process ID; negative values, other than -1, indicate a process group
* ID. If fildes does not refer to a socket, the results are unspecified.
*/
case F_SETOWN:
/* If fildes refers to a socket, set the process or process group ID specified
* to receive SIGURG signals when out-of-band data is available, using the value
* of the third argument, arg, taken as type int. Positive values indicate a
* process ID; negative values, other than -1, indicate a process group ID. If
* fildes does not refer to a socket, the results are unspecified.
*/
err = EBADF; /* Only valid on socket descriptors */
break;
case F_GETLK:
/* Get the first lock which blocks the lock description pointed to by the third
* argument, arg, taken as a pointer to type struct flock, defined in <fcntl.h>.
* The information retrieved shall overwrite the information passed to fcntl() in
* the structure flock. If no lock is found that would prevent this lock from being
* created, then the structure shall be left unchanged except for the lock type
* which shall be set to F_UNLCK.
*/
case F_SETLK:
/* Set or clear a file segment lock according to the lock description pointed to
* by the third argument, arg, taken as a pointer to type struct flock, defined in
* <fcntl.h>. F_SETLK can establish shared (or read) locks (F_RDLCK) or exclusive
* (or write) locks (F_WRLCK), as well as to remove either type of lock (F_UNLCK).
* F_RDLCK, F_WRLCK, and F_UNLCK are defined in <fcntl.h>. If a shared or exclusive
* lock cannot be set, fcntl() shall return immediately with a return value of -1.
*/
case F_SETLKW:
/* This command shall be equivalent to F_SETLK except that if a shared or exclusive
* lock is blocked by other locks, the thread shall wait until the request can be
* satisfied. If a signal that is to be caught is received while fcntl() is waiting
* for a region, fcntl() shall be interrupted. Upon return from the signal handler,
* fcntl() shall return -1 with errno set to [EINTR], and the lock operation shall
* not be done.
*/
err = ENOSYS; /* Not implemented */
break;
default:
err = EINVAL;
break;
}
errout:
if (err != 0)
{
errno = err;
return ERROR;
}
return ret;
}
#endif /* CONFIG_NFILE_DESCRIPTORS > 0 */
/****************************************************************************
* Global Functions
****************************************************************************/
int fcntl(int fildes, int cmd, ...)
{
va_list ap;
int ret;
/* Setup to access the variable argument list */
va_start(ap, cmd);
/* Did we get a valid file descriptor? */
#if CONFIG_NFILE_DESCRIPTORS > 0
if ((unsigned int)fildes < CONFIG_NFILE_DESCRIPTORS)
{
/* Yes.. defer file operations to file_vfcntl() */
ret = file_vfcntl(fildes, cmd, ap);
}
else
#endif
{
/* No... check for operations on a socket descriptor */
#if defined(CONFIG_NET) && CONFIG_NSOCKET_DESCRIPTORS > 0
if ((unsigned int)fildes < (CONFIG_NFILE_DESCRIPTORS+CONFIG_NSOCKET_DESCRIPTORS))
{
/* Yes.. defer socket descriptor operations to net_vfcntl() */
ret = net_vfcntl(fildes, cmd, ap);
}
else
#endif
{
/* No.. this descriptor number is out of range */
ret = EBADF;
}
}
va_end(ap);
return ret;
}