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/export.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 23 int vfs_readdir(struct file *file, filldir_t filler, void *buf) 24 { 25 struct inode *inode = file_inode(file); 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); 44 out: 45 return res; 46 } 47 48 EXPORT_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 61 struct 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 68 struct readdir_callback { 69 struct old_linux_dirent __user * dirent; 70 int result; 71 }; 72 73 static 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; 100 efault: 101 buf->result = -EFAULT; 102 return -EFAULT; 103 } 104 105 SYSCALL_DEFINE3(old_readdir, unsigned int, fd, 106 struct old_linux_dirent __user *, dirent, unsigned int, count) 107 { 108 int error; 109 struct fd f = fdget(fd); 110 struct readdir_callback buf; 111 112 if (!f.file) 113 return -EBADF; 114 115 buf.result = 0; 116 buf.dirent = dirent; 117 118 error = vfs_readdir(f.file, fillonedir, &buf); 119 if (buf.result) 120 error = buf.result; 121 122 fdput(f); 123 return error; 124 } 125 126 #endif /* __ARCH_WANT_OLD_READDIR */ 127 128 /* 129 * New, all-improved, singing, dancing, iBCS2-compliant getdents() 130 * interface. 131 */ 132 struct linux_dirent { 133 unsigned long d_ino; 134 unsigned long d_off; 135 unsigned short d_reclen; 136 char d_name[1]; 137 }; 138 139 struct getdents_callback { 140 struct linux_dirent __user * current_dir; 141 struct linux_dirent __user * previous; 142 int count; 143 int error; 144 }; 145 146 static int filldir(void * __buf, const char * name, int namlen, loff_t offset, 147 u64 ino, unsigned int d_type) 148 { 149 struct linux_dirent __user * dirent; 150 struct getdents_callback * buf = (struct getdents_callback *) __buf; 151 unsigned long d_ino; 152 int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2, 153 sizeof(long)); 154 155 buf->error = -EINVAL; /* only used if we fail.. */ 156 if (reclen > buf->count) 157 return -EINVAL; 158 d_ino = ino; 159 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) { 160 buf->error = -EOVERFLOW; 161 return -EOVERFLOW; 162 } 163 dirent = buf->previous; 164 if (dirent) { 165 if (__put_user(offset, &dirent->d_off)) 166 goto efault; 167 } 168 dirent = buf->current_dir; 169 if (__put_user(d_ino, &dirent->d_ino)) 170 goto efault; 171 if (__put_user(reclen, &dirent->d_reclen)) 172 goto efault; 173 if (copy_to_user(dirent->d_name, name, namlen)) 174 goto efault; 175 if (__put_user(0, dirent->d_name + namlen)) 176 goto efault; 177 if (__put_user(d_type, (char __user *) dirent + reclen - 1)) 178 goto efault; 179 buf->previous = dirent; 180 dirent = (void __user *)dirent + reclen; 181 buf->current_dir = dirent; 182 buf->count -= reclen; 183 return 0; 184 efault: 185 buf->error = -EFAULT; 186 return -EFAULT; 187 } 188 189 SYSCALL_DEFINE3(getdents, unsigned int, fd, 190 struct linux_dirent __user *, dirent, unsigned int, count) 191 { 192 struct fd f; 193 struct linux_dirent __user * lastdirent; 194 struct getdents_callback buf; 195 int error; 196 197 if (!access_ok(VERIFY_WRITE, dirent, count)) 198 return -EFAULT; 199 200 f = fdget(fd); 201 if (!f.file) 202 return -EBADF; 203 204 buf.current_dir = dirent; 205 buf.previous = NULL; 206 buf.count = count; 207 buf.error = 0; 208 209 error = vfs_readdir(f.file, filldir, &buf); 210 if (error >= 0) 211 error = buf.error; 212 lastdirent = buf.previous; 213 if (lastdirent) { 214 if (put_user(f.file->f_pos, &lastdirent->d_off)) 215 error = -EFAULT; 216 else 217 error = count - buf.count; 218 } 219 fdput(f); 220 return error; 221 } 222 223 struct getdents_callback64 { 224 struct linux_dirent64 __user * current_dir; 225 struct linux_dirent64 __user * previous; 226 int count; 227 int error; 228 }; 229 230 static int filldir64(void * __buf, const char * name, int namlen, loff_t offset, 231 u64 ino, unsigned int d_type) 232 { 233 struct linux_dirent64 __user *dirent; 234 struct getdents_callback64 * buf = (struct getdents_callback64 *) __buf; 235 int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1, 236 sizeof(u64)); 237 238 buf->error = -EINVAL; /* only used if we fail.. */ 239 if (reclen > buf->count) 240 return -EINVAL; 241 dirent = buf->previous; 242 if (dirent) { 243 if (__put_user(offset, &dirent->d_off)) 244 goto efault; 245 } 246 dirent = buf->current_dir; 247 if (__put_user(ino, &dirent->d_ino)) 248 goto efault; 249 if (__put_user(0, &dirent->d_off)) 250 goto efault; 251 if (__put_user(reclen, &dirent->d_reclen)) 252 goto efault; 253 if (__put_user(d_type, &dirent->d_type)) 254 goto efault; 255 if (copy_to_user(dirent->d_name, name, namlen)) 256 goto efault; 257 if (__put_user(0, dirent->d_name + namlen)) 258 goto efault; 259 buf->previous = dirent; 260 dirent = (void __user *)dirent + reclen; 261 buf->current_dir = dirent; 262 buf->count -= reclen; 263 return 0; 264 efault: 265 buf->error = -EFAULT; 266 return -EFAULT; 267 } 268 269 SYSCALL_DEFINE3(getdents64, unsigned int, fd, 270 struct linux_dirent64 __user *, dirent, unsigned int, count) 271 { 272 struct fd f; 273 struct linux_dirent64 __user * lastdirent; 274 struct getdents_callback64 buf; 275 int error; 276 277 if (!access_ok(VERIFY_WRITE, dirent, count)) 278 return -EFAULT; 279 280 f = fdget(fd); 281 if (!f.file) 282 return -EBADF; 283 284 buf.current_dir = dirent; 285 buf.previous = NULL; 286 buf.count = count; 287 buf.error = 0; 288 289 error = vfs_readdir(f.file, filldir64, &buf); 290 if (error >= 0) 291 error = buf.error; 292 lastdirent = buf.previous; 293 if (lastdirent) { 294 typeof(lastdirent->d_off) d_off = f.file->f_pos; 295 if (__put_user(d_off, &lastdirent->d_off)) 296 error = -EFAULT; 297 else 298 error = count - buf.count; 299 } 300 fdput(f); 301 return error; 302 } 303