1/**************************************************************************** 2 * fs/vfs/fs_truncate64.c 3 * 4 * Copyright (c) 2023 Huawei Device Co., Ltd. All rights reserved. 5 * Based on NuttX originally written by Gregory Nutt 6 * 7 * Copyright (C) 2018 Gregory Nutt. All rights reserved. 8 * Author: Gregory Nutt <gnutt@nuttx.org> 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in 18 * the documentation and/or other materials provided with the 19 * distribution. 20 * 3. Neither the name NuttX nor the names of its contributors may be 21 * used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 25 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 26 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 27 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 28 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 29 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 30 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 31 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 32 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 34 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35 * POSSIBILITY OF SUCH DAMAGE. 36 * 37 ****************************************************************************/ 38 39/**************************************************************************** 40 * Included Files 41 ****************************************************************************/ 42 43#include "vfs_config.h" 44#include "sys/types.h" 45#include "unistd.h" 46#include "fcntl.h" 47#include "sched.h" 48#include "assert.h" 49#include "errno.h" 50 51#include "vnode.h" 52 53/**************************************************************************** 54 * Name: file_truncate 55 * 56 * Description: 57 * Equivalent to the standard ftruncate() function except that is accepts 58 * a struct file instance instead of a file descriptor and it does not set 59 * the errno variable. 60 * 61 ****************************************************************************/ 62 63static int file_truncate64(struct file *filep, off64_t length) 64{ 65 struct Vnode *vnode = NULL; 66 int err; 67 68 /* Was this file opened for write access? */ 69 70 if (((unsigned int)(filep->f_oflags) & O_ACCMODE) == O_RDONLY) 71 { 72 err = -EACCES; 73 goto errout; 74 } 75 76 /* Is this vnode a registered mountpoint? Does it support the 77 * truncate operations may be relevant to device drivers but only 78 * the mountpoint operations vtable contains a truncate method. 79 */ 80 81 vnode = filep->f_vnode; 82 if (!vnode || !vnode->vop || !vnode->vop->Truncate64) 83 { 84 err = -ENOSYS; 85 goto errout; 86 } 87 88 /* Does the file system support the truncate method? It should if it is 89 * a write-able file system. 90 */ 91 92 err = vnode->vop->Truncate64(vnode, length); 93 if (err < 0) 94 { 95 goto errout; 96 } 97 98 return OK; 99 100errout: 101 set_errno(-err); 102 return VFS_ERROR; 103} 104 105/**************************************************************************** 106 * Name: ftruncate 107 * 108 * Description: 109 * The ftruncate() function causes the regular file referenced by fd to 110 * have a size of length bytes. 111 * 112 * If the file previously was larger than length, the extra data is 113 * discarded. If it was previously shorter than length, it is unspecified 114 * whether the file is changed or its size increased. If the file is 115 * extended, the extended area appears as if it were zero-filled. If fd 116 * references a shared memory object, ftruncate() sets the size of the 117 * shared memory object to length. If the file is not a regular file or 118 * a shared memory object, the result is unspecified. 119 120 * With ftruncate(), the file must be open for writing; for truncate(), 121 * the process must have write permission for the file. 122 * 123 * ftruncate() does not modify the file offset for any open file 124 * descriptions associated with the file. 125 * 126 * Input Parameters: 127 * fd - A reference to an open, regular file or shared memory object 128 * to be truncated. 129 * length - The new length of the file or shared memory object. 130 * 131 * Returned Value: 132 * On success, 0. 133 * On error, -1 is returned, and errno is set appro-priately: 134 * 135 * 136 ****************************************************************************/ 137 138int ftruncate64(int fd, off64_t length) 139{ 140#if CONFIG_NFILE_DESCRIPTORS > 0 141 struct file *filep = NULL; 142#endif 143 144 /* Did we get a valid file descriptor? */ 145 146#if CONFIG_NFILE_DESCRIPTORS > 0 147 if ((unsigned int)fd >= CONFIG_NFILE_DESCRIPTORS) 148#endif 149 { 150 set_errno(EBADF); 151 return VFS_ERROR; 152 } 153 154#if CONFIG_NFILE_DESCRIPTORS > 0 155 /* The descriptor is in the right range to be a file descriptor... write 156 * to the file. 157 */ 158 159 int ret = fs_getfilep(fd, &filep); 160 if (ret < 0) 161 { 162 /* The errno value has already been set */ 163 return VFS_ERROR; 164 } 165 166 if (filep->f_oflags & O_DIRECTORY) 167 { 168 set_errno(EBADF); 169 return VFS_ERROR; 170 } 171 172 /* Perform the truncate operation using the file descriptor as an index */ 173 174 return file_truncate64(filep, length); 175#endif 176} 177