1/* 2 * linux/fs/readdir.c 3 * 4 * Copyright (C) 1995 Linus Torvalds 5 */ 6 7#include <linux/stddef.h> 8#include <linux/kernel.h> 9#include <linux/module.h> 10#include <linux/time.h> 11#include <linux/mm.h> 12#include <linux/errno.h> 13#include <linux/stat.h> 14#include <linux/file.h> 15#include <linux/fs.h> 16#include <linux/dirent.h> 17#include <linux/security.h> 18#include <linux/syscalls.h> 19#include <linux/unistd.h> 20 21#include <asm/uaccess.h> 22 23int vfs_readdir(struct file *file, filldir_t filler, void *buf) 24{ 25 struct inode *inode = file->f_path.dentry->d_inode; 26 int res = -ENOTDIR; 27 if (!file->f_op || !file->f_op->readdir) 28 goto out; 29 30 res = security_file_permission(file, MAY_READ); 31 if (res) 32 goto out; 33 34 res = mutex_lock_killable(&inode->i_mutex); 35 if (res) 36 goto out; 37 38 res = -ENOENT; 39 if (!IS_DEADDIR(inode)) { 40 res = file->f_op->readdir(file, buf, filler); 41 file_accessed(file); 42 } 43 mutex_unlock(&inode->i_mutex); 44out: 45 return res; 46} 47 48EXPORT_SYMBOL(vfs_readdir); 49 50/* 51 * Traditional linux readdir() handling.. 52 * 53 * "count=1" is a special case, meaning that the buffer is one 54 * dirent-structure in size and that the code can't handle more 55 * anyway. Thus the special "fillonedir()" function for that 56 * case (the low-level handlers don't need to care about this). 57 */ 58 59#ifdef __ARCH_WANT_OLD_READDIR 60 61struct old_linux_dirent { 62 unsigned long d_ino; 63 unsigned long d_offset; 64 unsigned short d_namlen; 65 char d_name[1]; 66}; 67 68struct readdir_callback { 69 struct old_linux_dirent __user * dirent; 70 int result; 71}; 72 73static int fillonedir(void * __buf, const char * name, int namlen, loff_t offset, 74 u64 ino, unsigned int d_type) 75{ 76 struct readdir_callback * buf = (struct readdir_callback *) __buf; 77 struct old_linux_dirent __user * dirent; 78 unsigned long d_ino; 79 80 if (buf->result) 81 return -EINVAL; 82 d_ino = ino; 83 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) { 84 buf->result = -EOVERFLOW; 85 return -EOVERFLOW; 86 } 87 buf->result++; 88 dirent = buf->dirent; 89 if (!access_ok(VERIFY_WRITE, dirent, 90 (unsigned long)(dirent->d_name + namlen + 1) - 91 (unsigned long)dirent)) 92 goto efault; 93 if ( __put_user(d_ino, &dirent->d_ino) || 94 __put_user(offset, &dirent->d_offset) || 95 __put_user(namlen, &dirent->d_namlen) || 96 __copy_to_user(dirent->d_name, name, namlen) || 97 __put_user(0, dirent->d_name + namlen)) 98 goto efault; 99 return 0; 100efault: 101 buf->result = -EFAULT; 102 return -EFAULT; 103} 104 105SYSCALL_DEFINE3(old_readdir, unsigned int, fd, 106 struct old_linux_dirent __user *, dirent, unsigned int, count) 107{ 108 int error; 109 struct file * file; 110 struct readdir_callback buf; 111 112 error = -EBADF; 113 file = fget(fd); 114 if (!file) 115 goto out; 116 117 buf.result = 0; 118 buf.dirent = dirent; 119 120 error = vfs_readdir(file, fillonedir, &buf); 121 if (buf.result) 122 error = buf.result; 123 124 fput(file); 125out: 126 return error; 127} 128 129#endif /* __ARCH_WANT_OLD_READDIR */ 130 131/* 132 * New, all-improved, singing, dancing, iBCS2-compliant getdents() 133 * interface. 134 */ 135struct linux_dirent { 136 unsigned long d_ino; 137 unsigned long d_off; 138 unsigned short d_reclen; 139 char d_name[1]; 140}; 141 142struct getdents_callback { 143 struct linux_dirent __user * current_dir; 144 struct linux_dirent __user * previous; 145 int count; 146 int error; 147}; 148 149static int filldir(void * __buf, const char * name, int namlen, loff_t offset, 150 u64 ino, unsigned int d_type) 151{ 152 struct linux_dirent __user * dirent; 153 struct getdents_callback * buf = (struct getdents_callback *) __buf; 154 unsigned long d_ino; 155 int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2, 156 sizeof(long)); 157 158 buf->error = -EINVAL; /* only used if we fail.. */ 159 if (reclen > buf->count) 160 return -EINVAL; 161 d_ino = ino; 162 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) { 163 buf->error = -EOVERFLOW; 164 return -EOVERFLOW; 165 } 166 dirent = buf->previous; 167 if (dirent) { 168 if (__put_user(offset, &dirent->d_off)) 169 goto efault; 170 } 171 dirent = buf->current_dir; 172 if (__put_user(d_ino, &dirent->d_ino)) 173 goto efault; 174 if (__put_user(reclen, &dirent->d_reclen)) 175 goto efault; 176 if (copy_to_user(dirent->d_name, name, namlen)) 177 goto efault; 178 if (__put_user(0, dirent->d_name + namlen)) 179 goto efault; 180 if (__put_user(d_type, (char __user *) dirent + reclen - 1)) 181 goto efault; 182 buf->previous = dirent; 183 dirent = (void __user *)dirent + reclen; 184 buf->current_dir = dirent; 185 buf->count -= reclen; 186 return 0; 187efault: 188 buf->error = -EFAULT; 189 return -EFAULT; 190} 191 192SYSCALL_DEFINE3(getdents, unsigned int, fd, 193 struct linux_dirent __user *, dirent, unsigned int, count) 194{ 195 struct file * file; 196 struct linux_dirent __user * lastdirent; 197 struct getdents_callback buf; 198 int error; 199 200 error = -EFAULT; 201 if (!access_ok(VERIFY_WRITE, dirent, count)) 202 goto out; 203 204 error = -EBADF; 205 file = fget(fd); 206 if (!file) 207 goto out; 208 209 buf.current_dir = dirent; 210 buf.previous = NULL; 211 buf.count = count; 212 buf.error = 0; 213 214 error = vfs_readdir(file, filldir, &buf); 215 if (error >= 0) 216 error = buf.error; 217 lastdirent = buf.previous; 218 if (lastdirent) { 219 if (put_user(file->f_pos, &lastdirent->d_off)) 220 error = -EFAULT; 221 else 222 error = count - buf.count; 223 } 224 fput(file); 225out: 226 return error; 227} 228 229struct getdents_callback64 { 230 struct linux_dirent64 __user * current_dir; 231 struct linux_dirent64 __user * previous; 232 int count; 233 int error; 234}; 235 236static int filldir64(void * __buf, const char * name, int namlen, loff_t offset, 237 u64 ino, unsigned int d_type) 238{ 239 struct linux_dirent64 __user *dirent; 240 struct getdents_callback64 * buf = (struct getdents_callback64 *) __buf; 241 int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1, 242 sizeof(u64)); 243 244 buf->error = -EINVAL; /* only used if we fail.. */ 245 if (reclen > buf->count) 246 return -EINVAL; 247 dirent = buf->previous; 248 if (dirent) { 249 if (__put_user(offset, &dirent->d_off)) 250 goto efault; 251 } 252 dirent = buf->current_dir; 253 if (__put_user(ino, &dirent->d_ino)) 254 goto efault; 255 if (__put_user(0, &dirent->d_off)) 256 goto efault; 257 if (__put_user(reclen, &dirent->d_reclen)) 258 goto efault; 259 if (__put_user(d_type, &dirent->d_type)) 260 goto efault; 261 if (copy_to_user(dirent->d_name, name, namlen)) 262 goto efault; 263 if (__put_user(0, dirent->d_name + namlen)) 264 goto efault; 265 buf->previous = dirent; 266 dirent = (void __user *)dirent + reclen; 267 buf->current_dir = dirent; 268 buf->count -= reclen; 269 return 0; 270efault: 271 buf->error = -EFAULT; 272 return -EFAULT; 273} 274 275SYSCALL_DEFINE3(getdents64, unsigned int, fd, 276 struct linux_dirent64 __user *, dirent, unsigned int, count) 277{ 278 struct file * file; 279 struct linux_dirent64 __user * lastdirent; 280 struct getdents_callback64 buf; 281 int error; 282 283 error = -EFAULT; 284 if (!access_ok(VERIFY_WRITE, dirent, count)) 285 goto out; 286 287 error = -EBADF; 288 file = fget(fd); 289 if (!file) 290 goto out; 291 292 buf.current_dir = dirent; 293 buf.previous = NULL; 294 buf.count = count; 295 buf.error = 0; 296 297 error = vfs_readdir(file, filldir64, &buf); 298 if (error >= 0) 299 error = buf.error; 300 lastdirent = buf.previous; 301 if (lastdirent) { 302 typeof(lastdirent->d_off) d_off = file->f_pos; 303 if (__put_user(d_off, &lastdirent->d_off)) 304 error = -EFAULT; 305 else 306 error = count - buf.count; 307 } 308 fput(file); 309out: 310 return error; 311} 312