1 /* 2 * linux/fs/stat.c 3 * 4 * Copyright (C) 1991, 1992 Linus Torvalds 5 */ 6 7 #include <linux/config.h> 8 #include <linux/module.h> 9 #include <linux/mm.h> 10 #include <linux/errno.h> 11 #include <linux/file.h> 12 #include <linux/smp_lock.h> 13 #include <linux/highuid.h> 14 #include <linux/fs.h> 15 #include <linux/namei.h> 16 #include <linux/security.h> 17 #include <linux/syscalls.h> 18 19 #include <asm/uaccess.h> 20 #include <asm/unistd.h> 21 22 void generic_fillattr(struct inode *inode, struct kstat *stat) 23 { 24 stat->dev = inode->i_sb->s_dev; 25 stat->ino = inode->i_ino; 26 stat->mode = inode->i_mode; 27 stat->nlink = inode->i_nlink; 28 stat->uid = inode->i_uid; 29 stat->gid = inode->i_gid; 30 stat->rdev = inode->i_rdev; 31 stat->atime = inode->i_atime; 32 stat->mtime = inode->i_mtime; 33 stat->ctime = inode->i_ctime; 34 stat->size = i_size_read(inode); 35 stat->blocks = inode->i_blocks; 36 stat->blksize = inode->i_blksize; 37 } 38 39 EXPORT_SYMBOL(generic_fillattr); 40 41 int vfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) 42 { 43 struct inode *inode = dentry->d_inode; 44 int retval; 45 46 retval = security_inode_getattr(mnt, dentry); 47 if (retval) 48 return retval; 49 50 if (inode->i_op->getattr) 51 return inode->i_op->getattr(mnt, dentry, stat); 52 53 generic_fillattr(inode, stat); 54 if (!stat->blksize) { 55 struct super_block *s = inode->i_sb; 56 unsigned blocks; 57 blocks = (stat->size+s->s_blocksize-1) >> s->s_blocksize_bits; 58 stat->blocks = (s->s_blocksize / 512) * blocks; 59 stat->blksize = s->s_blocksize; 60 } 61 return 0; 62 } 63 64 EXPORT_SYMBOL(vfs_getattr); 65 66 int vfs_stat_fd(int dfd, char __user *name, struct kstat *stat) 67 { 68 struct nameidata nd; 69 int error; 70 71 error = __user_walk_fd(dfd, name, LOOKUP_FOLLOW, &nd); 72 if (!error) { 73 error = vfs_getattr(nd.mnt, nd.dentry, stat); 74 path_release(&nd); 75 } 76 return error; 77 } 78 79 int vfs_stat(char __user *name, struct kstat *stat) 80 { 81 return vfs_stat_fd(AT_FDCWD, name, stat); 82 } 83 84 EXPORT_SYMBOL(vfs_stat); 85 86 int vfs_lstat_fd(int dfd, char __user *name, struct kstat *stat) 87 { 88 struct nameidata nd; 89 int error; 90 91 error = __user_walk_fd(dfd, name, 0, &nd); 92 if (!error) { 93 error = vfs_getattr(nd.mnt, nd.dentry, stat); 94 path_release(&nd); 95 } 96 return error; 97 } 98 99 int vfs_lstat(char __user *name, struct kstat *stat) 100 { 101 return vfs_lstat_fd(AT_FDCWD, name, stat); 102 } 103 104 EXPORT_SYMBOL(vfs_lstat); 105 106 int vfs_fstat(unsigned int fd, struct kstat *stat) 107 { 108 struct file *f = fget(fd); 109 int error = -EBADF; 110 111 if (f) { 112 error = vfs_getattr(f->f_vfsmnt, f->f_dentry, stat); 113 fput(f); 114 } 115 return error; 116 } 117 118 EXPORT_SYMBOL(vfs_fstat); 119 120 #ifdef __ARCH_WANT_OLD_STAT 121 122 /* 123 * For backward compatibility? Maybe this should be moved 124 * into arch/i386 instead? 125 */ 126 static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf) 127 { 128 static int warncount = 5; 129 struct __old_kernel_stat tmp; 130 131 if (warncount > 0) { 132 warncount--; 133 printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n", 134 current->comm); 135 } else if (warncount < 0) { 136 /* it's laughable, but... */ 137 warncount = 0; 138 } 139 140 memset(&tmp, 0, sizeof(struct __old_kernel_stat)); 141 tmp.st_dev = old_encode_dev(stat->dev); 142 tmp.st_ino = stat->ino; 143 tmp.st_mode = stat->mode; 144 tmp.st_nlink = stat->nlink; 145 if (tmp.st_nlink != stat->nlink) 146 return -EOVERFLOW; 147 SET_UID(tmp.st_uid, stat->uid); 148 SET_GID(tmp.st_gid, stat->gid); 149 tmp.st_rdev = old_encode_dev(stat->rdev); 150 #if BITS_PER_LONG == 32 151 if (stat->size > MAX_NON_LFS) 152 return -EOVERFLOW; 153 #endif 154 tmp.st_size = stat->size; 155 tmp.st_atime = stat->atime.tv_sec; 156 tmp.st_mtime = stat->mtime.tv_sec; 157 tmp.st_ctime = stat->ctime.tv_sec; 158 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; 159 } 160 161 asmlinkage long sys_stat(char __user * filename, struct __old_kernel_stat __user * statbuf) 162 { 163 struct kstat stat; 164 int error = vfs_stat_fd(AT_FDCWD, filename, &stat); 165 166 if (!error) 167 error = cp_old_stat(&stat, statbuf); 168 169 return error; 170 } 171 asmlinkage long sys_lstat(char __user * filename, struct __old_kernel_stat __user * statbuf) 172 { 173 struct kstat stat; 174 int error = vfs_lstat_fd(AT_FDCWD, filename, &stat); 175 176 if (!error) 177 error = cp_old_stat(&stat, statbuf); 178 179 return error; 180 } 181 asmlinkage long sys_fstat(unsigned int fd, struct __old_kernel_stat __user * statbuf) 182 { 183 struct kstat stat; 184 int error = vfs_fstat(fd, &stat); 185 186 if (!error) 187 error = cp_old_stat(&stat, statbuf); 188 189 return error; 190 } 191 192 #endif /* __ARCH_WANT_OLD_STAT */ 193 194 static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf) 195 { 196 struct stat tmp; 197 198 #if BITS_PER_LONG == 32 199 if (!old_valid_dev(stat->dev) || !old_valid_dev(stat->rdev)) 200 return -EOVERFLOW; 201 #else 202 if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev)) 203 return -EOVERFLOW; 204 #endif 205 206 memset(&tmp, 0, sizeof(tmp)); 207 #if BITS_PER_LONG == 32 208 tmp.st_dev = old_encode_dev(stat->dev); 209 #else 210 tmp.st_dev = new_encode_dev(stat->dev); 211 #endif 212 tmp.st_ino = stat->ino; 213 tmp.st_mode = stat->mode; 214 tmp.st_nlink = stat->nlink; 215 if (tmp.st_nlink != stat->nlink) 216 return -EOVERFLOW; 217 SET_UID(tmp.st_uid, stat->uid); 218 SET_GID(tmp.st_gid, stat->gid); 219 #if BITS_PER_LONG == 32 220 tmp.st_rdev = old_encode_dev(stat->rdev); 221 #else 222 tmp.st_rdev = new_encode_dev(stat->rdev); 223 #endif 224 #if BITS_PER_LONG == 32 225 if (stat->size > MAX_NON_LFS) 226 return -EOVERFLOW; 227 #endif 228 tmp.st_size = stat->size; 229 tmp.st_atime = stat->atime.tv_sec; 230 tmp.st_mtime = stat->mtime.tv_sec; 231 tmp.st_ctime = stat->ctime.tv_sec; 232 #ifdef STAT_HAVE_NSEC 233 tmp.st_atime_nsec = stat->atime.tv_nsec; 234 tmp.st_mtime_nsec = stat->mtime.tv_nsec; 235 tmp.st_ctime_nsec = stat->ctime.tv_nsec; 236 #endif 237 tmp.st_blocks = stat->blocks; 238 tmp.st_blksize = stat->blksize; 239 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; 240 } 241 242 asmlinkage long sys_newstat(char __user *filename, struct stat __user *statbuf) 243 { 244 struct kstat stat; 245 int error = vfs_stat_fd(AT_FDCWD, filename, &stat); 246 247 if (!error) 248 error = cp_new_stat(&stat, statbuf); 249 250 return error; 251 } 252 253 asmlinkage long sys_newlstat(char __user *filename, struct stat __user *statbuf) 254 { 255 struct kstat stat; 256 int error = vfs_lstat_fd(AT_FDCWD, filename, &stat); 257 258 if (!error) 259 error = cp_new_stat(&stat, statbuf); 260 261 return error; 262 } 263 264 asmlinkage long sys_newfstatat(int dfd, char __user *filename, 265 struct stat __user *statbuf, int flag) 266 { 267 struct kstat stat; 268 int error = -EINVAL; 269 270 if ((flag & ~AT_SYMLINK_NOFOLLOW) != 0) 271 goto out; 272 273 if (flag & AT_SYMLINK_NOFOLLOW) 274 error = vfs_lstat_fd(dfd, filename, &stat); 275 else 276 error = vfs_stat_fd(dfd, filename, &stat); 277 278 if (!error) 279 error = cp_new_stat(&stat, statbuf); 280 281 out: 282 return error; 283 } 284 285 asmlinkage long sys_newfstat(unsigned int fd, struct stat __user *statbuf) 286 { 287 struct kstat stat; 288 int error = vfs_fstat(fd, &stat); 289 290 if (!error) 291 error = cp_new_stat(&stat, statbuf); 292 293 return error; 294 } 295 296 asmlinkage long sys_readlinkat(int dfd, const char __user *path, 297 char __user *buf, int bufsiz) 298 { 299 struct nameidata nd; 300 int error; 301 302 if (bufsiz <= 0) 303 return -EINVAL; 304 305 error = __user_walk_fd(dfd, path, 0, &nd); 306 if (!error) { 307 struct inode * inode = nd.dentry->d_inode; 308 309 error = -EINVAL; 310 if (inode->i_op && inode->i_op->readlink) { 311 error = security_inode_readlink(nd.dentry); 312 if (!error) { 313 touch_atime(nd.mnt, nd.dentry); 314 error = inode->i_op->readlink(nd.dentry, buf, bufsiz); 315 } 316 } 317 path_release(&nd); 318 } 319 return error; 320 } 321 322 asmlinkage long sys_readlink(const char __user *path, char __user *buf, 323 int bufsiz) 324 { 325 return sys_readlinkat(AT_FDCWD, path, buf, bufsiz); 326 } 327 328 329 /* ---------- LFS-64 ----------- */ 330 #ifdef __ARCH_WANT_STAT64 331 332 static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf) 333 { 334 struct stat64 tmp; 335 336 memset(&tmp, 0, sizeof(struct stat64)); 337 #ifdef CONFIG_MIPS 338 /* mips has weird padding, so we don't get 64 bits there */ 339 if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev)) 340 return -EOVERFLOW; 341 tmp.st_dev = new_encode_dev(stat->dev); 342 tmp.st_rdev = new_encode_dev(stat->rdev); 343 #else 344 tmp.st_dev = huge_encode_dev(stat->dev); 345 tmp.st_rdev = huge_encode_dev(stat->rdev); 346 #endif 347 tmp.st_ino = stat->ino; 348 #ifdef STAT64_HAS_BROKEN_ST_INO 349 tmp.__st_ino = stat->ino; 350 #endif 351 tmp.st_mode = stat->mode; 352 tmp.st_nlink = stat->nlink; 353 tmp.st_uid = stat->uid; 354 tmp.st_gid = stat->gid; 355 tmp.st_atime = stat->atime.tv_sec; 356 tmp.st_atime_nsec = stat->atime.tv_nsec; 357 tmp.st_mtime = stat->mtime.tv_sec; 358 tmp.st_mtime_nsec = stat->mtime.tv_nsec; 359 tmp.st_ctime = stat->ctime.tv_sec; 360 tmp.st_ctime_nsec = stat->ctime.tv_nsec; 361 tmp.st_size = stat->size; 362 tmp.st_blocks = stat->blocks; 363 tmp.st_blksize = stat->blksize; 364 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; 365 } 366 367 asmlinkage long sys_stat64(char __user * filename, struct stat64 __user * statbuf) 368 { 369 struct kstat stat; 370 int error = vfs_stat(filename, &stat); 371 372 if (!error) 373 error = cp_new_stat64(&stat, statbuf); 374 375 return error; 376 } 377 asmlinkage long sys_lstat64(char __user * filename, struct stat64 __user * statbuf) 378 { 379 struct kstat stat; 380 int error = vfs_lstat(filename, &stat); 381 382 if (!error) 383 error = cp_new_stat64(&stat, statbuf); 384 385 return error; 386 } 387 asmlinkage long sys_fstat64(unsigned long fd, struct stat64 __user * statbuf) 388 { 389 struct kstat stat; 390 int error = vfs_fstat(fd, &stat); 391 392 if (!error) 393 error = cp_new_stat64(&stat, statbuf); 394 395 return error; 396 } 397 398 #endif /* __ARCH_WANT_STAT64 */ 399 400 void inode_add_bytes(struct inode *inode, loff_t bytes) 401 { 402 spin_lock(&inode->i_lock); 403 inode->i_blocks += bytes >> 9; 404 bytes &= 511; 405 inode->i_bytes += bytes; 406 if (inode->i_bytes >= 512) { 407 inode->i_blocks++; 408 inode->i_bytes -= 512; 409 } 410 spin_unlock(&inode->i_lock); 411 } 412 413 EXPORT_SYMBOL(inode_add_bytes); 414 415 void inode_sub_bytes(struct inode *inode, loff_t bytes) 416 { 417 spin_lock(&inode->i_lock); 418 inode->i_blocks -= bytes >> 9; 419 bytes &= 511; 420 if (inode->i_bytes < bytes) { 421 inode->i_blocks--; 422 inode->i_bytes += 512; 423 } 424 inode->i_bytes -= bytes; 425 spin_unlock(&inode->i_lock); 426 } 427 428 EXPORT_SYMBOL(inode_sub_bytes); 429 430 loff_t inode_get_bytes(struct inode *inode) 431 { 432 loff_t ret; 433 434 spin_lock(&inode->i_lock); 435 ret = (((loff_t)inode->i_blocks) << 9) + inode->i_bytes; 436 spin_unlock(&inode->i_lock); 437 return ret; 438 } 439 440 EXPORT_SYMBOL(inode_get_bytes); 441 442 void inode_set_bytes(struct inode *inode, loff_t bytes) 443 { 444 /* Caller is here responsible for sufficient locking 445 * (ie. inode->i_lock) */ 446 inode->i_blocks = bytes >> 9; 447 inode->i_bytes = bytes & 511; 448 } 449 450 EXPORT_SYMBOL(inode_set_bytes); 451