1 /* 2 * linux/fs/readdir.c 3 * 4 * Copyright (C) 1995 Linus Torvalds 5 */ 6 7 #include <linux/module.h> 8 #include <linux/time.h> 9 #include <linux/mm.h> 10 #include <linux/errno.h> 11 #include <linux/stat.h> 12 #include <linux/file.h> 13 #include <linux/fs.h> 14 #include <linux/dirent.h> 15 #include <linux/security.h> 16 #include <linux/syscalls.h> 17 #include <linux/unistd.h> 18 19 #include <asm/uaccess.h> 20 21 int vfs_readdir(struct file *file, filldir_t filler, void *buf) 22 { 23 struct inode *inode = file->f_path.dentry->d_inode; 24 int res = -ENOTDIR; 25 if (!file->f_op || !file->f_op->readdir) 26 goto out; 27 28 res = security_file_permission(file, MAY_READ); 29 if (res) 30 goto out; 31 32 mutex_lock(&inode->i_mutex); 33 res = -ENOENT; 34 if (!IS_DEADDIR(inode)) { 35 res = file->f_op->readdir(file, buf, filler); 36 file_accessed(file); 37 } 38 mutex_unlock(&inode->i_mutex); 39 out: 40 return res; 41 } 42 43 EXPORT_SYMBOL(vfs_readdir); 44 45 /* 46 * Traditional linux readdir() handling.. 47 * 48 * "count=1" is a special case, meaning that the buffer is one 49 * dirent-structure in size and that the code can't handle more 50 * anyway. Thus the special "fillonedir()" function for that 51 * case (the low-level handlers don't need to care about this). 52 */ 53 #define NAME_OFFSET(de) ((int) ((de)->d_name - (char __user *) (de))) 54 #define ROUND_UP(x) (((x)+sizeof(long)-1) & ~(sizeof(long)-1)) 55 56 #ifdef __ARCH_WANT_OLD_READDIR 57 58 struct old_linux_dirent { 59 unsigned long d_ino; 60 unsigned long d_offset; 61 unsigned short d_namlen; 62 char d_name[1]; 63 }; 64 65 struct readdir_callback { 66 struct old_linux_dirent __user * dirent; 67 int result; 68 }; 69 70 static int fillonedir(void * __buf, const char * name, int namlen, loff_t offset, 71 u64 ino, unsigned int d_type) 72 { 73 struct readdir_callback * buf = (struct readdir_callback *) __buf; 74 struct old_linux_dirent __user * dirent; 75 unsigned long d_ino; 76 77 if (buf->result) 78 return -EINVAL; 79 d_ino = ino; 80 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) 81 return -EOVERFLOW; 82 buf->result++; 83 dirent = buf->dirent; 84 if (!access_ok(VERIFY_WRITE, dirent, 85 (unsigned long)(dirent->d_name + namlen + 1) - 86 (unsigned long)dirent)) 87 goto efault; 88 if ( __put_user(d_ino, &dirent->d_ino) || 89 __put_user(offset, &dirent->d_offset) || 90 __put_user(namlen, &dirent->d_namlen) || 91 __copy_to_user(dirent->d_name, name, namlen) || 92 __put_user(0, dirent->d_name + namlen)) 93 goto efault; 94 return 0; 95 efault: 96 buf->result = -EFAULT; 97 return -EFAULT; 98 } 99 100 asmlinkage long old_readdir(unsigned int fd, struct old_linux_dirent __user * dirent, unsigned int count) 101 { 102 int error; 103 struct file * file; 104 struct readdir_callback buf; 105 106 error = -EBADF; 107 file = fget(fd); 108 if (!file) 109 goto out; 110 111 buf.result = 0; 112 buf.dirent = dirent; 113 114 error = vfs_readdir(file, fillonedir, &buf); 115 if (error >= 0) 116 error = buf.result; 117 118 fput(file); 119 out: 120 return error; 121 } 122 123 #endif /* __ARCH_WANT_OLD_READDIR */ 124 125 /* 126 * New, all-improved, singing, dancing, iBCS2-compliant getdents() 127 * interface. 128 */ 129 struct linux_dirent { 130 unsigned long d_ino; 131 unsigned long d_off; 132 unsigned short d_reclen; 133 char d_name[1]; 134 }; 135 136 struct getdents_callback { 137 struct linux_dirent __user * current_dir; 138 struct linux_dirent __user * previous; 139 int count; 140 int error; 141 }; 142 143 static int filldir(void * __buf, const char * name, int namlen, loff_t offset, 144 u64 ino, unsigned int d_type) 145 { 146 struct linux_dirent __user * dirent; 147 struct getdents_callback * buf = (struct getdents_callback *) __buf; 148 unsigned long d_ino; 149 int reclen = ROUND_UP(NAME_OFFSET(dirent) + namlen + 2); 150 151 buf->error = -EINVAL; /* only used if we fail.. */ 152 if (reclen > buf->count) 153 return -EINVAL; 154 d_ino = ino; 155 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) 156 return -EOVERFLOW; 157 dirent = buf->previous; 158 if (dirent) { 159 if (__put_user(offset, &dirent->d_off)) 160 goto efault; 161 } 162 dirent = buf->current_dir; 163 if (__put_user(d_ino, &dirent->d_ino)) 164 goto efault; 165 if (__put_user(reclen, &dirent->d_reclen)) 166 goto efault; 167 if (copy_to_user(dirent->d_name, name, namlen)) 168 goto efault; 169 if (__put_user(0, dirent->d_name + namlen)) 170 goto efault; 171 if (__put_user(d_type, (char __user *) dirent + reclen - 1)) 172 goto efault; 173 buf->previous = dirent; 174 dirent = (void __user *)dirent + reclen; 175 buf->current_dir = dirent; 176 buf->count -= reclen; 177 return 0; 178 efault: 179 buf->error = -EFAULT; 180 return -EFAULT; 181 } 182 183 asmlinkage long sys_getdents(unsigned int fd, struct linux_dirent __user * dirent, unsigned int count) 184 { 185 struct file * file; 186 struct linux_dirent __user * lastdirent; 187 struct getdents_callback buf; 188 int error; 189 190 error = -EFAULT; 191 if (!access_ok(VERIFY_WRITE, dirent, count)) 192 goto out; 193 194 error = -EBADF; 195 file = fget(fd); 196 if (!file) 197 goto out; 198 199 buf.current_dir = dirent; 200 buf.previous = NULL; 201 buf.count = count; 202 buf.error = 0; 203 204 error = vfs_readdir(file, filldir, &buf); 205 if (error < 0) 206 goto out_putf; 207 error = buf.error; 208 lastdirent = buf.previous; 209 if (lastdirent) { 210 if (put_user(file->f_pos, &lastdirent->d_off)) 211 error = -EFAULT; 212 else 213 error = count - buf.count; 214 } 215 216 out_putf: 217 fput(file); 218 out: 219 return error; 220 } 221 222 #define ROUND_UP64(x) (((x)+sizeof(u64)-1) & ~(sizeof(u64)-1)) 223 224 struct getdents_callback64 { 225 struct linux_dirent64 __user * current_dir; 226 struct linux_dirent64 __user * previous; 227 int count; 228 int error; 229 }; 230 231 static int filldir64(void * __buf, const char * name, int namlen, loff_t offset, 232 u64 ino, unsigned int d_type) 233 { 234 struct linux_dirent64 __user *dirent; 235 struct getdents_callback64 * buf = (struct getdents_callback64 *) __buf; 236 int reclen = ROUND_UP64(NAME_OFFSET(dirent) + namlen + 1); 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 asmlinkage long sys_getdents64(unsigned int fd, struct linux_dirent64 __user * dirent, unsigned int count) 270 { 271 struct file * file; 272 struct linux_dirent64 __user * lastdirent; 273 struct getdents_callback64 buf; 274 int error; 275 276 error = -EFAULT; 277 if (!access_ok(VERIFY_WRITE, dirent, count)) 278 goto out; 279 280 error = -EBADF; 281 file = fget(fd); 282 if (!file) 283 goto out; 284 285 buf.current_dir = dirent; 286 buf.previous = NULL; 287 buf.count = count; 288 buf.error = 0; 289 290 error = vfs_readdir(file, filldir64, &buf); 291 if (error < 0) 292 goto out_putf; 293 error = buf.error; 294 lastdirent = buf.previous; 295 if (lastdirent) { 296 typeof(lastdirent->d_off) d_off = file->f_pos; 297 error = -EFAULT; 298 if (__put_user(d_off, &lastdirent->d_off)) 299 goto out_putf; 300 error = count - buf.count; 301 } 302 303 out_putf: 304 fput(file); 305 out: 306 return error; 307 } 308