1 /* 2 * linux/fs/readdir.c 3 * 4 * Copyright (C) 1995 Linus Torvalds 5 */ 6 7 #include <linux/kernel.h> 8 #include <linux/module.h> 9 #include <linux/time.h> 10 #include <linux/mm.h> 11 #include <linux/errno.h> 12 #include <linux/stat.h> 13 #include <linux/file.h> 14 #include <linux/fs.h> 15 #include <linux/dirent.h> 16 #include <linux/security.h> 17 #include <linux/syscalls.h> 18 #include <linux/unistd.h> 19 20 #include <asm/uaccess.h> 21 22 int vfs_readdir(struct file *file, filldir_t filler, void *buf) 23 { 24 struct inode *inode = file->f_path.dentry->d_inode; 25 int res = -ENOTDIR; 26 if (!file->f_op || !file->f_op->readdir) 27 goto out; 28 29 res = security_file_permission(file, MAY_READ); 30 if (res) 31 goto out; 32 33 res = mutex_lock_killable(&inode->i_mutex); 34 if (res) 35 goto out; 36 37 res = -ENOENT; 38 if (!IS_DEADDIR(inode)) { 39 res = file->f_op->readdir(file, buf, filler); 40 file_accessed(file); 41 } 42 mutex_unlock(&inode->i_mutex); 43 out: 44 return res; 45 } 46 47 EXPORT_SYMBOL(vfs_readdir); 48 49 /* 50 * Traditional linux readdir() handling.. 51 * 52 * "count=1" is a special case, meaning that the buffer is one 53 * dirent-structure in size and that the code can't handle more 54 * anyway. Thus the special "fillonedir()" function for that 55 * case (the low-level handlers don't need to care about this). 56 */ 57 #define NAME_OFFSET(de) ((int) ((de)->d_name - (char __user *) (de))) 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 asmlinkage long sys_old_readdir(unsigned int fd, struct old_linux_dirent __user * dirent, unsigned int count) 106 { 107 int error; 108 struct file * file; 109 struct readdir_callback buf; 110 111 error = -EBADF; 112 file = fget(fd); 113 if (!file) 114 goto out; 115 116 buf.result = 0; 117 buf.dirent = dirent; 118 119 error = vfs_readdir(file, fillonedir, &buf); 120 if (buf.result) 121 error = buf.result; 122 123 fput(file); 124 out: 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(NAME_OFFSET(dirent) + namlen + 2, sizeof(long)); 155 156 buf->error = -EINVAL; /* only used if we fail.. */ 157 if (reclen > buf->count) 158 return -EINVAL; 159 d_ino = ino; 160 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) { 161 buf->error = -EOVERFLOW; 162 return -EOVERFLOW; 163 } 164 dirent = buf->previous; 165 if (dirent) { 166 if (__put_user(offset, &dirent->d_off)) 167 goto efault; 168 } 169 dirent = buf->current_dir; 170 if (__put_user(d_ino, &dirent->d_ino)) 171 goto efault; 172 if (__put_user(reclen, &dirent->d_reclen)) 173 goto efault; 174 if (copy_to_user(dirent->d_name, name, namlen)) 175 goto efault; 176 if (__put_user(0, dirent->d_name + namlen)) 177 goto efault; 178 if (__put_user(d_type, (char __user *) dirent + reclen - 1)) 179 goto efault; 180 buf->previous = dirent; 181 dirent = (void __user *)dirent + reclen; 182 buf->current_dir = dirent; 183 buf->count -= reclen; 184 return 0; 185 efault: 186 buf->error = -EFAULT; 187 return -EFAULT; 188 } 189 190 asmlinkage long sys_getdents(unsigned int fd, struct linux_dirent __user * dirent, unsigned int count) 191 { 192 struct file * file; 193 struct linux_dirent __user * lastdirent; 194 struct getdents_callback buf; 195 int error; 196 197 error = -EFAULT; 198 if (!access_ok(VERIFY_WRITE, dirent, count)) 199 goto out; 200 201 error = -EBADF; 202 file = fget(fd); 203 if (!file) 204 goto out; 205 206 buf.current_dir = dirent; 207 buf.previous = NULL; 208 buf.count = count; 209 buf.error = 0; 210 211 error = vfs_readdir(file, filldir, &buf); 212 if (error >= 0) 213 error = buf.error; 214 lastdirent = buf.previous; 215 if (lastdirent) { 216 if (put_user(file->f_pos, &lastdirent->d_off)) 217 error = -EFAULT; 218 else 219 error = count - buf.count; 220 } 221 fput(file); 222 out: 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(NAME_OFFSET(dirent) + namlen + 1, sizeof(u64)); 239 240 buf->error = -EINVAL; /* only used if we fail.. */ 241 if (reclen > buf->count) 242 return -EINVAL; 243 dirent = buf->previous; 244 if (dirent) { 245 if (__put_user(offset, &dirent->d_off)) 246 goto efault; 247 } 248 dirent = buf->current_dir; 249 if (__put_user(ino, &dirent->d_ino)) 250 goto efault; 251 if (__put_user(0, &dirent->d_off)) 252 goto efault; 253 if (__put_user(reclen, &dirent->d_reclen)) 254 goto efault; 255 if (__put_user(d_type, &dirent->d_type)) 256 goto efault; 257 if (copy_to_user(dirent->d_name, name, namlen)) 258 goto efault; 259 if (__put_user(0, dirent->d_name + namlen)) 260 goto efault; 261 buf->previous = dirent; 262 dirent = (void __user *)dirent + reclen; 263 buf->current_dir = dirent; 264 buf->count -= reclen; 265 return 0; 266 efault: 267 buf->error = -EFAULT; 268 return -EFAULT; 269 } 270 271 asmlinkage long sys_getdents64(unsigned int fd, struct linux_dirent64 __user * dirent, unsigned int count) 272 { 273 struct file * file; 274 struct linux_dirent64 __user * lastdirent; 275 struct getdents_callback64 buf; 276 int error; 277 278 error = -EFAULT; 279 if (!access_ok(VERIFY_WRITE, dirent, count)) 280 goto out; 281 282 error = -EBADF; 283 file = fget(fd); 284 if (!file) 285 goto out; 286 287 buf.current_dir = dirent; 288 buf.previous = NULL; 289 buf.count = count; 290 buf.error = 0; 291 292 error = vfs_readdir(file, filldir64, &buf); 293 if (error >= 0) 294 error = buf.error; 295 lastdirent = buf.previous; 296 if (lastdirent) { 297 typeof(lastdirent->d_off) d_off = file->f_pos; 298 if (__put_user(d_off, &lastdirent->d_off)) 299 error = -EFAULT; 300 else 301 error = count - buf.count; 302 } 303 fput(file); 304 out: 305 return error; 306 } 307