367 lines
12 KiB
C
367 lines
12 KiB
C
/****************************************************************************
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* fs/vfs/fs_fcntl.c
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*
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* Copyright (C) 2009, 2012-2014, 2016-2017 Gregory Nutt. All rights
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* 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 <stdarg.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <assert.h>
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#include <nuttx/sched.h>
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#include <nuttx/cancelpt.h>
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#include <nuttx/fs/fs.h>
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#include <nuttx/net/net.h>
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#include "inode/inode.h"
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: file_vfcntl
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*
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* Description:
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* Similar to the standard vfcntl function except that is accepts a struct
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* struct file instance instead of a file descriptor.
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*
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* Input Parameters:
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* filep - Instance for struct file for the opened file.
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* cmd - Identifies the operation to be performed.
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* ap - Variable argument following the command.
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*
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* Returned Value:
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* The nature of the return value depends on the command. Non-negative
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* values indicate success. Failures are reported as negated errno
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* values.
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*
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****************************************************************************/
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int file_vfcntl(FAR struct file *filep, int cmd, va_list ap)
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{
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int ret = -EINVAL;
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/* Was this file opened ? */
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if (!filep->f_inode)
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{
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return -EBADF;
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}
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switch (cmd)
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{
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case F_DUPFD:
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/* Return a new file descriptor which shall be the lowest numbered
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* available (that is, not already open) file descriptor greater than
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* or equal to the third argument, arg, taken as an integer of type
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* int. The new file descriptor shall refer to the same open file
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* description as the original file descriptor, and shall share any
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* locks. The FD_CLOEXEC flag associated with the new file descriptor
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* shall be cleared to keep the file open across calls to one of the
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* exec functions.
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*/
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{
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/* Does not set the errno variable in the event of a failure */
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ret = file_dup(filep, va_arg(ap, int));
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}
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break;
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case F_GETFD:
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/* Get the file descriptor flags defined in <fcntl.h> that are associated
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* with the file descriptor fd. File descriptor flags are associated
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* with a single file descriptor and do not affect other file descriptors
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* that refer to the same file.
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*/
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{
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ret = filep->f_oflags & O_CLOEXEC ? FD_CLOEXEC : 0;
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}
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break;
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case F_SETFD:
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/* Set the file descriptor flags defined in <fcntl.h>, that are
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* associated with fd, to the third argument, arg, taken as type int.
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* If the FD_CLOEXEC flag in the third argument is 0, the file shall
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* remain open across the exec functions; otherwise, the file shall
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* be closed upon successful execution of one of the exec functions.
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*/
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{
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int oflags = va_arg(ap, int);
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if (oflags & ~FD_CLOEXEC)
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{
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ret = -ENOSYS;
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break;
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}
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if (oflags & FD_CLOEXEC)
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{
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filep->f_oflags |= O_CLOEXEC;
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}
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else
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{
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filep->f_oflags &= ~O_CLOEXEC;
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}
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}
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break;
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case F_GETFL:
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/* Get the file status flags and file access modes, defined in
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* <fcntl.h>, for the file description associated with fd. The file
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* access modes can be extracted from the return value using the
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* mask O_ACCMODE, which is defined in <fcntl.h>. File status flags
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* and file access modes are associated with the file description
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* and do not affect other file descriptors that refer to the same
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* file with different open file descriptions.
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*/
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{
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ret = filep->f_oflags;
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}
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break;
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case F_SETFL:
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/* Set the file status flags, defined in <fcntl.h>, for the file
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* description associated with fd from the corresponding bits in
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* the third argument, arg, taken as type int. Bits corresponding
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* to the file access mode and the file creation flags, as defined
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* in <fcntl.h>, that are set in arg shall be ignored. If any bits
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* in arg other than those mentioned here are changed by the
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* application, the result is unspecified.
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*/
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{
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int oflags = va_arg(ap, int);
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oflags &= FFCNTL;
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filep->f_oflags &= ~FFCNTL;
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filep->f_oflags |= oflags;
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ret = OK;
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}
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break;
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case F_GETOWN:
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/* If fd refers to a socket, get the process or process group ID
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* specified to receive SIGURG signals when out-of-band data is
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* available. Positive values indicate a process ID; negative
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* values, other than -1, indicate a process group ID. If fd does
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* not refer to a socket, the results are unspecified.
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*/
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case F_SETOWN:
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/* If fd refers to a socket, set the process or process group ID
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* specified to receive SIGURG signals when out-of-band data is
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* available, using the value of the third argument, arg, taken as
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* type int. Positive values indicate a process ID; negative values,
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* other than -1, indicate a process group ID. If fd does not refer
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* to a socket, the results are unspecified.
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*/
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ret = -EBADF; /* Only valid on socket descriptors */
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break;
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case F_GETLK:
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/* Get the first lock which blocks the lock description pointed to
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* by the third argument, arg, taken as a pointer to type struct
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* flock, defined in <fcntl.h>. The information retrieved shall
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* overwrite the information passed to fcntl() in the structure
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* flock. If no lock is found that would prevent this lock from
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* being created, then the structure shall be left unchanged except
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* for the lock type which shall be set to F_UNLCK.
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*/
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case F_SETLK:
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/* Set or clear a file segment lock according to the lock
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* description pointed to by the third argument, arg, taken as a
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* pointer to type struct flock, defined in <fcntl.h>. F_SETLK can
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* establish shared (or read) locks (F_RDLCK) or exclusive (or
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* write) locks (F_WRLCK), as well as to remove either type of lock
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* (F_UNLCK). F_RDLCK, F_WRLCK, and F_UNLCK are defined in
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* <fcntl.h>. If a shared or exclusive lock cannot be set, fcntl()
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* shall return immediately with a return value of -1.
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*/
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case F_SETLKW:
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/* This command shall be equivalent to F_SETLK except that if a
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* shared or exclusive lock is blocked by other locks, the thread
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* shall wait until the request can be satisfied. If a signal that
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* is to be caught is received while fcntl() is waiting for a
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* region, fcntl() shall be interrupted. Upon return from the signal
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* handler, fcntl() shall return -1 with errno set to [EINTR], and
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* the lock operation shall not be done.
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*/
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ret = -ENOSYS; /* Not implemented */
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break;
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default:
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break;
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}
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return ret;
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}
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/****************************************************************************
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* Name: file_fcntl
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*
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* Description:
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* Similar to the standard fcntl function except that is accepts a struct
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* struct file instance instead of a file descriptor.
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*
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* Input Parameters:
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* filep - Instance for struct file for the opened file.
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* cmd - Identifies the operation to be performed. Command specific
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* arguments may follow.
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*
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* Returned Value:
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* The nature of the return value depends on the command. Non-negative
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* values indicate success. Failures are reported as negated errno
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* values.
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*
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****************************************************************************/
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int file_fcntl(FAR struct file *filep, int cmd, ...)
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{
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va_list ap;
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int ret;
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/* Setup to access the variable argument list */
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va_start(ap, cmd);
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/* Let file_vfcntl() do the real work. The errno is not set on
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* failures.
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*/
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ret = file_vfcntl(filep, cmd, ap);
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va_end(ap);
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return ret;
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}
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/****************************************************************************
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* Name: fcntl
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*
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* Description:
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* fcntl() will perform the operation specified by 'cmd' on an open file.
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*
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* Input Parameters:
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* fd - File descriptor of the open file
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* cmd - Identifies the operation to be performed. Command specific
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* arguments may follow.
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*
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* Returned Value:
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* The returned value depends on the nature of the command but for all
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* commands the return value of -1 (ERROR) indicates that an error has
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* occurred and, in this case, the errno variable will be set
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* appropriately
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*
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****************************************************************************/
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int fcntl(int fd, int cmd, ...)
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{
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FAR struct file *filep;
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va_list ap;
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int ret;
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/* fcntl() is a cancellation point */
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enter_cancellation_point();
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/* Setup to access the variable argument list */
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va_start(ap, cmd);
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/* Did we get a valid file descriptor? */
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if ((unsigned int)fd < CONFIG_NFILE_DESCRIPTORS)
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{
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/* Get the file structure corresponding to the file descriptor. */
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ret = fs_getfilep(fd, &filep);
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if (ret >= 0)
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{
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DEBUGASSERT(filep != NULL);
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/* Let file_vfcntl() do the real work. The errno is not set on
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* failures.
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*/
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ret = file_vfcntl(filep, cmd, ap);
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}
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}
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else
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{
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/* No... check for operations on a socket descriptor */
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#ifdef CONFIG_NET
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if ((unsigned int)fd < (CONFIG_NFILE_DESCRIPTORS + CONFIG_NSOCKET_DESCRIPTORS))
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{
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/* Yes.. defer socket descriptor operations to net_vfcntl(). The
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* errno is not set on failures.
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*/
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ret = net_vfcntl(fd, cmd, ap);
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}
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else
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#endif
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{
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/* No.. this descriptor number is out of range */
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ret = -EBADF;
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}
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}
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va_end(ap);
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if (ret < 0)
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{
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set_errno(-ret);
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ret = ERROR;
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}
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leave_cancellation_point();
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return ret;
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}
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