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->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); 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 file * file; 110 struct readdir_callback buf; 111 int fput_needed; 112 113 file = fget_light(fd, &fput_needed); 114 if (!file) 115 return -EBADF; 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_light(file, fput_needed); 125 return error; 126 } 127 128 #endif /* __ARCH_WANT_OLD_READDIR */ 129 130 /* 131 * New, all-improved, singing, dancing, iBCS2-compliant getdents() 132 * interface. 133 */ 134 struct linux_dirent { 135 unsigned long d_ino; 136 unsigned long d_off; 137 unsigned short d_reclen; 138 char d_name[1]; 139 }; 140 141 struct getdents_callback { 142 struct linux_dirent __user * current_dir; 143 struct linux_dirent __user * previous; 144 int count; 145 int error; 146 }; 147 148 static int filldir(void * __buf, const char * name, int namlen, loff_t offset, 149 u64 ino, unsigned int d_type) 150 { 151 struct linux_dirent __user * dirent; 152 struct getdents_callback * buf = (struct getdents_callback *) __buf; 153 unsigned long d_ino; 154 int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2, 155 sizeof(long)); 156 157 buf->error = -EINVAL; /* only used if we fail.. */ 158 if (reclen > buf->count) 159 return -EINVAL; 160 d_ino = ino; 161 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) { 162 buf->error = -EOVERFLOW; 163 return -EOVERFLOW; 164 } 165 dirent = buf->previous; 166 if (dirent) { 167 if (__put_user(offset, &dirent->d_off)) 168 goto efault; 169 } 170 dirent = buf->current_dir; 171 if (__put_user(d_ino, &dirent->d_ino)) 172 goto efault; 173 if (__put_user(reclen, &dirent->d_reclen)) 174 goto efault; 175 if (copy_to_user(dirent->d_name, name, namlen)) 176 goto efault; 177 if (__put_user(0, dirent->d_name + namlen)) 178 goto efault; 179 if (__put_user(d_type, (char __user *) dirent + reclen - 1)) 180 goto efault; 181 buf->previous = dirent; 182 dirent = (void __user *)dirent + reclen; 183 buf->current_dir = dirent; 184 buf->count -= reclen; 185 return 0; 186 efault: 187 buf->error = -EFAULT; 188 return -EFAULT; 189 } 190 191 SYSCALL_DEFINE3(getdents, unsigned int, fd, 192 struct linux_dirent __user *, dirent, unsigned int, count) 193 { 194 struct file * file; 195 struct linux_dirent __user * lastdirent; 196 struct getdents_callback buf; 197 int fput_needed; 198 int error; 199 200 if (!access_ok(VERIFY_WRITE, dirent, count)) 201 return -EFAULT; 202 203 file = fget_light(fd, &fput_needed); 204 if (!file) 205 return -EBADF; 206 207 buf.current_dir = dirent; 208 buf.previous = NULL; 209 buf.count = count; 210 buf.error = 0; 211 212 error = vfs_readdir(file, filldir, &buf); 213 if (error >= 0) 214 error = buf.error; 215 lastdirent = buf.previous; 216 if (lastdirent) { 217 if (put_user(file->f_pos, &lastdirent->d_off)) 218 error = -EFAULT; 219 else 220 error = count - buf.count; 221 } 222 fput_light(file, fput_needed); 223 return error; 224 } 225 226 struct getdents_callback64 { 227 struct linux_dirent64 __user * current_dir; 228 struct linux_dirent64 __user * previous; 229 int count; 230 int error; 231 }; 232 233 static int filldir64(void * __buf, const char * name, int namlen, loff_t offset, 234 u64 ino, unsigned int d_type) 235 { 236 struct linux_dirent64 __user *dirent; 237 struct getdents_callback64 * buf = (struct getdents_callback64 *) __buf; 238 int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1, 239 sizeof(u64)); 240 241 buf->error = -EINVAL; /* only used if we fail.. */ 242 if (reclen > buf->count) 243 return -EINVAL; 244 dirent = buf->previous; 245 if (dirent) { 246 if (__put_user(offset, &dirent->d_off)) 247 goto efault; 248 } 249 dirent = buf->current_dir; 250 if (__put_user(ino, &dirent->d_ino)) 251 goto efault; 252 if (__put_user(0, &dirent->d_off)) 253 goto efault; 254 if (__put_user(reclen, &dirent->d_reclen)) 255 goto efault; 256 if (__put_user(d_type, &dirent->d_type)) 257 goto efault; 258 if (copy_to_user(dirent->d_name, name, namlen)) 259 goto efault; 260 if (__put_user(0, dirent->d_name + namlen)) 261 goto efault; 262 buf->previous = dirent; 263 dirent = (void __user *)dirent + reclen; 264 buf->current_dir = dirent; 265 buf->count -= reclen; 266 return 0; 267 efault: 268 buf->error = -EFAULT; 269 return -EFAULT; 270 } 271 272 SYSCALL_DEFINE3(getdents64, unsigned int, fd, 273 struct linux_dirent64 __user *, dirent, unsigned int, count) 274 { 275 struct file * file; 276 struct linux_dirent64 __user * lastdirent; 277 struct getdents_callback64 buf; 278 int fput_needed; 279 int error; 280 281 if (!access_ok(VERIFY_WRITE, dirent, count)) 282 return -EFAULT; 283 284 file = fget_light(fd, &fput_needed); 285 if (!file) 286 return -EBADF; 287 288 buf.current_dir = dirent; 289 buf.previous = NULL; 290 buf.count = count; 291 buf.error = 0; 292 293 error = vfs_readdir(file, filldir64, &buf); 294 if (error >= 0) 295 error = buf.error; 296 lastdirent = buf.previous; 297 if (lastdirent) { 298 typeof(lastdirent->d_off) d_off = file->f_pos; 299 if (__put_user(d_off, &lastdirent->d_off)) 300 error = -EFAULT; 301 else 302 error = count - buf.count; 303 } 304 fput_light(file, fput_needed); 305 return error; 306 } 307