/**************************************************************************** * fs/vfs/fs_fcntl.c * * Copyright (C) 2009, 2012-2014, 2016-2017 Gregory Nutt. All rights * reserved. * Author: Gregory Nutt * * 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 #include #include #include #include #include #include #include #include #include "inode/inode.h" /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: file_vfcntl * * Description: * Similar to the standard vfcntl function except that is accepts a struct * struct file instance instead of a file descriptor. * * Input Parameters: * filep - Instance for struct file for the opened file. * cmd - Indentifies the operation to be performed. * ap - Variable argument following the command. * * Returned Value: * The nature of the return value depends on the command. Non-negative * values indicate success. Failures are reported as negated errno * values. * ****************************************************************************/ int file_vfcntl(FAR struct file *filep, int cmd, va_list ap) { int ret = -EINVAL; /* Was this file opened ? */ if (!filep->f_inode) { return -EBADF; } 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. */ { /* Does not set the errno variable in the event of a failure */ ret = file_dup(filep, va_arg(ap, int)); } break; case F_GETFD: /* Get the file descriptor flags defined in that are associated * with the file descriptor fd. File descriptor flags are associated * with a single file descriptor and do not affect other file descriptors * that refer to the same file. */ { ret = filep->f_oflags & O_CLOEXEC ? FD_CLOEXEC : 0; } break; case F_SETFD: /* Set the file descriptor flags defined in , that are * associated with fd, 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. */ { int oflags = va_arg(ap, int); if (oflags & ~FD_CLOEXEC) { ret = -ENOSYS; break; } if (oflags & FD_CLOEXEC) { filep->f_oflags |= O_CLOEXEC; } else { filep->f_oflags &= ~O_CLOEXEC; } } break; case F_GETFL: /* Get the file status flags and file access modes, defined in * , for the file description associated with fd. The file * access modes can be extracted from the return value using the * mask O_ACCMODE, which is defined in . 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 = filep->f_oflags; } break; case F_SETFL: /* Set the file status flags, defined in , for the file * description associated with fd 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 , 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. */ { int oflags = va_arg(ap, int); oflags &= FFCNTL; filep->f_oflags &= ~FFCNTL; filep->f_oflags |= oflags; ret = OK; } break; case F_GETOWN: /* If fd 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 fd does * not refer to a socket, the results are unspecified. */ case F_SETOWN: /* If fd 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 fd does not refer * to a socket, the results are unspecified. */ ret = -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 . 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 . 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 * . 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. */ ret = -ENOSYS; /* Not implemented */ break; default: break; } return ret; } /**************************************************************************** * Name: file_fcntl * * Description: * Similar to the standard fcntl function except that is accepts a struct * struct file instance instead of a file descriptor. * * Input Parameters: * filep - Instance for struct file for the opened file. * cmd - Identifies the operation to be performed. Command specific * arguments may follow. * * Returned Value: * The nature of the return value depends on the command. Non-negative * values indicate success. Failures are reported as negated errno * values. * ****************************************************************************/ int file_fcntl(FAR struct file *filep, int cmd, ...) { va_list ap; int ret; /* Setup to access the variable argument list */ va_start(ap, cmd); /* Let file_vfcntl() do the real work. The errno is not set on * failures. */ ret = file_vfcntl(filep, cmd, ap); va_end(ap); return ret; } /**************************************************************************** * Name: fcntl * * Description: * fcntl() will perform the operation specified by 'cmd' on an open file. * * Input Parameters: * fd - File descriptor of the open file * cmd - Identifies the operation to be performed. Command specific * arguments may follow. * * Returned Value: * The returned value depends on the nature of the command but for all * commands the return value of -1 (ERROR) indicates that an error has * occurred and, in this case, the errno variable will be set * appropriately * ****************************************************************************/ int fcntl(int fd, int cmd, ...) { FAR struct file *filep; va_list ap; int ret; /* fcntl() is a cancellation point */ enter_cancellation_point(); /* Setup to access the variable argument list */ va_start(ap, cmd); /* Did we get a valid file descriptor? */ if ((unsigned int)fd < CONFIG_NFILE_DESCRIPTORS) { /* Get the file structure corresponding to the file descriptor. */ ret = fs_getfilep(fd, &filep); if (ret >= 0) { DEBUGASSERT(filep != NULL); /* Let file_vfcntl() do the real work. The errno is not set on * failures. */ ret = file_vfcntl(filep, cmd, ap); } } else { /* No... check for operations on a socket descriptor */ #ifdef CONFIG_NET if ((unsigned int)fd < (CONFIG_NFILE_DESCRIPTORS + CONFIG_NSOCKET_DESCRIPTORS)) { /* Yes.. defer socket descriptor operations to net_vfcntl(). The * errno is not set on failures. */ ret = net_vfcntl(fd, cmd, ap); } else #endif { /* No.. this descriptor number is out of range */ ret = -EBADF; } } va_end(ap); if (ret < 0) { set_errno(-ret); ret = ERROR; } leave_cancellation_point(); return ret; }