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/smp_lock.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 mutex_lock(&inode->i_mutex); 34 res = -ENOENT; 35 if (!IS_DEADDIR(inode)) { 36 res = file->f_op->readdir(file, buf, filler); 37 file_accessed(file); 38 } 39 mutex_unlock(&inode->i_mutex); 40 out: 41 return res; 42 } 43 44 EXPORT_SYMBOL(vfs_readdir); 45 46 /* 47 * Traditional linux readdir() handling.. 48 * 49 * "count=1" is a special case, meaning that the buffer is one 50 * dirent-structure in size and that the code can't handle more 51 * anyway. Thus the special "fillonedir()" function for that 52 * case (the low-level handlers don't need to care about this). 53 */ 54 #define NAME_OFFSET(de) ((int) ((de)->d_name - (char __user *) (de))) 55 #define ROUND_UP(x) (((x)+sizeof(long)-1) & ~(sizeof(long)-1)) 56 57 #ifdef __ARCH_WANT_OLD_READDIR 58 59 struct old_linux_dirent { 60 unsigned long d_ino; 61 unsigned long d_offset; 62 unsigned short d_namlen; 63 char d_name[1]; 64 }; 65 66 struct readdir_callback { 67 struct old_linux_dirent __user * dirent; 68 int result; 69 }; 70 71 static int fillonedir(void * __buf, const char * name, int namlen, loff_t offset, 72 u64 ino, unsigned int d_type) 73 { 74 struct readdir_callback * buf = (struct readdir_callback *) __buf; 75 struct old_linux_dirent __user * dirent; 76 unsigned long d_ino; 77 78 if (buf->result) 79 return -EINVAL; 80 d_ino = ino; 81 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) 82 return -EOVERFLOW; 83 buf->result++; 84 dirent = buf->dirent; 85 if (!access_ok(VERIFY_WRITE, dirent, 86 (unsigned long)(dirent->d_name + namlen + 1) - 87 (unsigned long)dirent)) 88 goto efault; 89 if ( __put_user(d_ino, &dirent->d_ino) || 90 __put_user(offset, &dirent->d_offset) || 91 __put_user(namlen, &dirent->d_namlen) || 92 __copy_to_user(dirent->d_name, name, namlen) || 93 __put_user(0, dirent->d_name + namlen)) 94 goto efault; 95 return 0; 96 efault: 97 buf->result = -EFAULT; 98 return -EFAULT; 99 } 100 101 asmlinkage long old_readdir(unsigned int fd, struct old_linux_dirent __user * dirent, unsigned int count) 102 { 103 int error; 104 struct file * file; 105 struct readdir_callback buf; 106 107 error = -EBADF; 108 file = fget(fd); 109 if (!file) 110 goto out; 111 112 buf.result = 0; 113 buf.dirent = dirent; 114 115 error = vfs_readdir(file, fillonedir, &buf); 116 if (error >= 0) 117 error = buf.result; 118 119 fput(file); 120 out: 121 return error; 122 } 123 124 #endif /* __ARCH_WANT_OLD_READDIR */ 125 126 /* 127 * New, all-improved, singing, dancing, iBCS2-compliant getdents() 128 * interface. 129 */ 130 struct linux_dirent { 131 unsigned long d_ino; 132 unsigned long d_off; 133 unsigned short d_reclen; 134 char d_name[1]; 135 }; 136 137 struct getdents_callback { 138 struct linux_dirent __user * current_dir; 139 struct linux_dirent __user * previous; 140 int count; 141 int error; 142 }; 143 144 static int filldir(void * __buf, const char * name, int namlen, loff_t offset, 145 u64 ino, unsigned int d_type) 146 { 147 struct linux_dirent __user * dirent; 148 struct getdents_callback * buf = (struct getdents_callback *) __buf; 149 unsigned long d_ino; 150 int reclen = ROUND_UP(NAME_OFFSET(dirent) + namlen + 2); 151 152 buf->error = -EINVAL; /* only used if we fail.. */ 153 if (reclen > buf->count) 154 return -EINVAL; 155 d_ino = ino; 156 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) 157 return -EOVERFLOW; 158 dirent = buf->previous; 159 if (dirent) { 160 if (__put_user(offset, &dirent->d_off)) 161 goto efault; 162 } 163 dirent = buf->current_dir; 164 if (__put_user(d_ino, &dirent->d_ino)) 165 goto efault; 166 if (__put_user(reclen, &dirent->d_reclen)) 167 goto efault; 168 if (copy_to_user(dirent->d_name, name, namlen)) 169 goto efault; 170 if (__put_user(0, dirent->d_name + namlen)) 171 goto efault; 172 if (__put_user(d_type, (char __user *) dirent + reclen - 1)) 173 goto efault; 174 buf->previous = dirent; 175 dirent = (void __user *)dirent + reclen; 176 buf->current_dir = dirent; 177 buf->count -= reclen; 178 return 0; 179 efault: 180 buf->error = -EFAULT; 181 return -EFAULT; 182 } 183 184 asmlinkage long sys_getdents(unsigned int fd, struct linux_dirent __user * dirent, unsigned int count) 185 { 186 struct file * file; 187 struct linux_dirent __user * lastdirent; 188 struct getdents_callback buf; 189 int error; 190 191 error = -EFAULT; 192 if (!access_ok(VERIFY_WRITE, dirent, count)) 193 goto out; 194 195 error = -EBADF; 196 file = fget(fd); 197 if (!file) 198 goto out; 199 200 buf.current_dir = dirent; 201 buf.previous = NULL; 202 buf.count = count; 203 buf.error = 0; 204 205 error = vfs_readdir(file, filldir, &buf); 206 if (error < 0) 207 goto out_putf; 208 error = buf.error; 209 lastdirent = buf.previous; 210 if (lastdirent) { 211 if (put_user(file->f_pos, &lastdirent->d_off)) 212 error = -EFAULT; 213 else 214 error = count - buf.count; 215 } 216 217 out_putf: 218 fput(file); 219 out: 220 return error; 221 } 222 223 #define ROUND_UP64(x) (((x)+sizeof(u64)-1) & ~(sizeof(u64)-1)) 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 = ROUND_UP64(NAME_OFFSET(dirent) + namlen + 1); 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