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 return -EOVERFLOW; 85 buf->result++; 86 dirent = buf->dirent; 87 if (!access_ok(VERIFY_WRITE, dirent, 88 (unsigned long)(dirent->d_name + namlen + 1) - 89 (unsigned long)dirent)) 90 goto efault; 91 if ( __put_user(d_ino, &dirent->d_ino) || 92 __put_user(offset, &dirent->d_offset) || 93 __put_user(namlen, &dirent->d_namlen) || 94 __copy_to_user(dirent->d_name, name, namlen) || 95 __put_user(0, dirent->d_name + namlen)) 96 goto efault; 97 return 0; 98 efault: 99 buf->result = -EFAULT; 100 return -EFAULT; 101 } 102 103 asmlinkage long old_readdir(unsigned int fd, struct old_linux_dirent __user * dirent, unsigned int count) 104 { 105 int error; 106 struct file * file; 107 struct readdir_callback buf; 108 109 error = -EBADF; 110 file = fget(fd); 111 if (!file) 112 goto out; 113 114 buf.result = 0; 115 buf.dirent = dirent; 116 117 error = vfs_readdir(file, fillonedir, &buf); 118 if (error >= 0) 119 error = buf.result; 120 121 fput(file); 122 out: 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(NAME_OFFSET(dirent) + namlen + 2, sizeof(long)); 153 154 buf->error = -EINVAL; /* only used if we fail.. */ 155 if (reclen > buf->count) 156 return -EINVAL; 157 d_ino = ino; 158 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) 159 return -EOVERFLOW; 160 dirent = buf->previous; 161 if (dirent) { 162 if (__put_user(offset, &dirent->d_off)) 163 goto efault; 164 } 165 dirent = buf->current_dir; 166 if (__put_user(d_ino, &dirent->d_ino)) 167 goto efault; 168 if (__put_user(reclen, &dirent->d_reclen)) 169 goto efault; 170 if (copy_to_user(dirent->d_name, name, namlen)) 171 goto efault; 172 if (__put_user(0, dirent->d_name + namlen)) 173 goto efault; 174 if (__put_user(d_type, (char __user *) dirent + reclen - 1)) 175 goto efault; 176 buf->previous = dirent; 177 dirent = (void __user *)dirent + reclen; 178 buf->current_dir = dirent; 179 buf->count -= reclen; 180 return 0; 181 efault: 182 buf->error = -EFAULT; 183 return -EFAULT; 184 } 185 186 asmlinkage long sys_getdents(unsigned int fd, struct linux_dirent __user * dirent, unsigned int count) 187 { 188 struct file * file; 189 struct linux_dirent __user * lastdirent; 190 struct getdents_callback buf; 191 int error; 192 193 error = -EFAULT; 194 if (!access_ok(VERIFY_WRITE, dirent, count)) 195 goto out; 196 197 error = -EBADF; 198 file = fget(fd); 199 if (!file) 200 goto out; 201 202 buf.current_dir = dirent; 203 buf.previous = NULL; 204 buf.count = count; 205 buf.error = 0; 206 207 error = vfs_readdir(file, filldir, &buf); 208 if (error < 0) 209 goto out_putf; 210 error = buf.error; 211 lastdirent = buf.previous; 212 if (lastdirent) { 213 if (put_user(file->f_pos, &lastdirent->d_off)) 214 error = -EFAULT; 215 else 216 error = count - buf.count; 217 } 218 219 out_putf: 220 fput(file); 221 out: 222 return error; 223 } 224 225 struct getdents_callback64 { 226 struct linux_dirent64 __user * current_dir; 227 struct linux_dirent64 __user * previous; 228 int count; 229 int error; 230 }; 231 232 static int filldir64(void * __buf, const char * name, int namlen, loff_t offset, 233 u64 ino, unsigned int d_type) 234 { 235 struct linux_dirent64 __user *dirent; 236 struct getdents_callback64 * buf = (struct getdents_callback64 *) __buf; 237 int reclen = ALIGN(NAME_OFFSET(dirent) + namlen + 1, sizeof(u64)); 238 239 buf->error = -EINVAL; /* only used if we fail.. */ 240 if (reclen > buf->count) 241 return -EINVAL; 242 dirent = buf->previous; 243 if (dirent) { 244 if (__put_user(offset, &dirent->d_off)) 245 goto efault; 246 } 247 dirent = buf->current_dir; 248 if (__put_user(ino, &dirent->d_ino)) 249 goto efault; 250 if (__put_user(0, &dirent->d_off)) 251 goto efault; 252 if (__put_user(reclen, &dirent->d_reclen)) 253 goto efault; 254 if (__put_user(d_type, &dirent->d_type)) 255 goto efault; 256 if (copy_to_user(dirent->d_name, name, namlen)) 257 goto efault; 258 if (__put_user(0, dirent->d_name + namlen)) 259 goto efault; 260 buf->previous = dirent; 261 dirent = (void __user *)dirent + reclen; 262 buf->current_dir = dirent; 263 buf->count -= reclen; 264 return 0; 265 efault: 266 buf->error = -EFAULT; 267 return -EFAULT; 268 } 269 270 asmlinkage long sys_getdents64(unsigned int fd, struct linux_dirent64 __user * dirent, unsigned int count) 271 { 272 struct file * file; 273 struct linux_dirent64 __user * lastdirent; 274 struct getdents_callback64 buf; 275 int error; 276 277 error = -EFAULT; 278 if (!access_ok(VERIFY_WRITE, dirent, count)) 279 goto out; 280 281 error = -EBADF; 282 file = fget(fd); 283 if (!file) 284 goto out; 285 286 buf.current_dir = dirent; 287 buf.previous = NULL; 288 buf.count = count; 289 buf.error = 0; 290 291 error = vfs_readdir(file, filldir64, &buf); 292 if (error < 0) 293 goto out_putf; 294 error = buf.error; 295 lastdirent = buf.previous; 296 if (lastdirent) { 297 typeof(lastdirent->d_off) d_off = file->f_pos; 298 error = -EFAULT; 299 if (__put_user(d_off, &lastdirent->d_off)) 300 goto out_putf; 301 error = count - buf.count; 302 } 303 304 out_putf: 305 fput(file); 306 out: 307 return error; 308 } 309