/fs/stat.c
C | 471 lines | 380 code | 76 blank | 15 comment | 55 complexity | 3de8b008e09908711bebbc840d5d5878 MD5 | raw file
Possible License(s): LGPL-2.0, AGPL-1.0, GPL-2.0
1/* 2 * linux/fs/stat.c 3 * 4 * Copyright (C) 1991, 1992 Linus Torvalds 5 */ 6 7#include <linux/module.h> 8#include <linux/mm.h> 9#include <linux/errno.h> 10#include <linux/file.h> 11#include <linux/highuid.h> 12#include <linux/fs.h> 13#include <linux/namei.h> 14#include <linux/security.h> 15#include <linux/syscalls.h> 16#include <linux/pagemap.h> 17 18#include <asm/uaccess.h> 19#include <asm/unistd.h> 20 21void generic_fillattr(struct inode *inode, struct kstat *stat) 22{ 23 stat->dev = inode->i_sb->s_dev; 24 stat->ino = inode->i_ino; 25 stat->mode = inode->i_mode; 26 stat->nlink = inode->i_nlink; 27 stat->uid = inode->i_uid; 28 stat->gid = inode->i_gid; 29 stat->rdev = inode->i_rdev; 30 stat->size = i_size_read(inode); 31 stat->atime = inode->i_atime; 32 stat->mtime = inode->i_mtime; 33 stat->ctime = inode->i_ctime; 34 stat->blksize = (1 << inode->i_blkbits); 35 stat->blocks = inode->i_blocks; 36} 37 38EXPORT_SYMBOL(generic_fillattr); 39 40int vfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) 41{ 42 struct inode *inode = dentry->d_inode; 43 int retval; 44 45 retval = security_inode_getattr(mnt, dentry); 46 if (retval) 47 return retval; 48 49 if (inode->i_op->getattr) 50 return inode->i_op->getattr(mnt, dentry, stat); 51 52 generic_fillattr(inode, stat); 53 return 0; 54} 55 56EXPORT_SYMBOL(vfs_getattr); 57 58int vfs_fstat(unsigned int fd, struct kstat *stat) 59{ 60 struct file *f = fget(fd); 61 int error = -EBADF; 62 63 if (f) { 64 error = vfs_getattr(f->f_path.mnt, f->f_path.dentry, stat); 65 fput(f); 66 } 67 return error; 68} 69EXPORT_SYMBOL(vfs_fstat); 70 71int vfs_fstatat(int dfd, const char __user *filename, struct kstat *stat, 72 int flag) 73{ 74 struct path path; 75 int error = -EINVAL; 76 int lookup_flags = 0; 77 78 if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT | 79 AT_EMPTY_PATH)) != 0) 80 goto out; 81 82 if (!(flag & AT_SYMLINK_NOFOLLOW)) 83 lookup_flags |= LOOKUP_FOLLOW; 84 if (flag & AT_EMPTY_PATH) 85 lookup_flags |= LOOKUP_EMPTY; 86 87 error = user_path_at(dfd, filename, lookup_flags, &path); 88 if (error) 89 goto out; 90 91 error = vfs_getattr(path.mnt, path.dentry, stat); 92 path_put(&path); 93out: 94 return error; 95} 96EXPORT_SYMBOL(vfs_fstatat); 97 98int vfs_stat(const char __user *name, struct kstat *stat) 99{ 100 return vfs_fstatat(AT_FDCWD, name, stat, 0); 101} 102EXPORT_SYMBOL(vfs_stat); 103 104int vfs_lstat(const char __user *name, struct kstat *stat) 105{ 106 return vfs_fstatat(AT_FDCWD, name, stat, AT_SYMLINK_NOFOLLOW); 107} 108EXPORT_SYMBOL(vfs_lstat); 109 110 111#ifdef __ARCH_WANT_OLD_STAT 112 113/* 114 * For backward compatibility? Maybe this should be moved 115 * into arch/i386 instead? 116 */ 117static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf) 118{ 119 static int warncount = 5; 120 struct __old_kernel_stat tmp; 121 122 if (warncount > 0) { 123 warncount--; 124 printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n", 125 current->comm); 126 } else if (warncount < 0) { 127 /* it's laughable, but... */ 128 warncount = 0; 129 } 130 131 memset(&tmp, 0, sizeof(struct __old_kernel_stat)); 132 tmp.st_dev = old_encode_dev(stat->dev); 133 tmp.st_ino = stat->ino; 134 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino) 135 return -EOVERFLOW; 136 tmp.st_mode = stat->mode; 137 tmp.st_nlink = stat->nlink; 138 if (tmp.st_nlink != stat->nlink) 139 return -EOVERFLOW; 140 SET_UID(tmp.st_uid, stat->uid); 141 SET_GID(tmp.st_gid, stat->gid); 142 tmp.st_rdev = old_encode_dev(stat->rdev); 143#if BITS_PER_LONG == 32 144 if (stat->size > MAX_NON_LFS) 145 return -EOVERFLOW; 146#endif 147 tmp.st_size = stat->size; 148 tmp.st_atime = stat->atime.tv_sec; 149 tmp.st_mtime = stat->mtime.tv_sec; 150 tmp.st_ctime = stat->ctime.tv_sec; 151 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; 152} 153 154SYSCALL_DEFINE2(stat, const char __user *, filename, 155 struct __old_kernel_stat __user *, statbuf) 156{ 157 struct kstat stat; 158 int error; 159 160 error = vfs_stat(filename, &stat); 161 if (error) 162 return error; 163 164 return cp_old_stat(&stat, statbuf); 165} 166 167SYSCALL_DEFINE2(lstat, const char __user *, filename, 168 struct __old_kernel_stat __user *, statbuf) 169{ 170 struct kstat stat; 171 int error; 172 173 error = vfs_lstat(filename, &stat); 174 if (error) 175 return error; 176 177 return cp_old_stat(&stat, statbuf); 178} 179 180SYSCALL_DEFINE2(fstat, unsigned int, fd, struct __old_kernel_stat __user *, statbuf) 181{ 182 struct kstat stat; 183 int error = vfs_fstat(fd, &stat); 184 185 if (!error) 186 error = cp_old_stat(&stat, statbuf); 187 188 return error; 189} 190 191#endif /* __ARCH_WANT_OLD_STAT */ 192 193static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf) 194{ 195 struct stat tmp; 196 197#if BITS_PER_LONG == 32 198 if (!old_valid_dev(stat->dev) || !old_valid_dev(stat->rdev)) 199 return -EOVERFLOW; 200#else 201 if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev)) 202 return -EOVERFLOW; 203#endif 204 205 memset(&tmp, 0, sizeof(tmp)); 206#if BITS_PER_LONG == 32 207 tmp.st_dev = old_encode_dev(stat->dev); 208#else 209 tmp.st_dev = new_encode_dev(stat->dev); 210#endif 211 tmp.st_ino = stat->ino; 212 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino) 213 return -EOVERFLOW; 214 tmp.st_mode = stat->mode; 215 tmp.st_nlink = stat->nlink; 216 if (tmp.st_nlink != stat->nlink) 217 return -EOVERFLOW; 218 SET_UID(tmp.st_uid, stat->uid); 219 SET_GID(tmp.st_gid, stat->gid); 220#if BITS_PER_LONG == 32 221 tmp.st_rdev = old_encode_dev(stat->rdev); 222#else 223 tmp.st_rdev = new_encode_dev(stat->rdev); 224#endif 225#if BITS_PER_LONG == 32 226 if (stat->size > MAX_NON_LFS) 227 return -EOVERFLOW; 228#endif 229 tmp.st_size = stat->size; 230 tmp.st_atime = stat->atime.tv_sec; 231 tmp.st_mtime = stat->mtime.tv_sec; 232 tmp.st_ctime = stat->ctime.tv_sec; 233#ifdef STAT_HAVE_NSEC 234 tmp.st_atime_nsec = stat->atime.tv_nsec; 235 tmp.st_mtime_nsec = stat->mtime.tv_nsec; 236 tmp.st_ctime_nsec = stat->ctime.tv_nsec; 237#endif 238 tmp.st_blocks = stat->blocks; 239 tmp.st_blksize = stat->blksize; 240 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; 241} 242 243SYSCALL_DEFINE2(newstat, const char __user *, filename, 244 struct stat __user *, statbuf) 245{ 246 struct kstat stat; 247 int error = vfs_stat(filename, &stat); 248 249 if (error) 250 return error; 251 return cp_new_stat(&stat, statbuf); 252} 253 254SYSCALL_DEFINE2(newlstat, const char __user *, filename, 255 struct stat __user *, statbuf) 256{ 257 struct kstat stat; 258 int error; 259 260 error = vfs_lstat(filename, &stat); 261 if (error) 262 return error; 263 264 return cp_new_stat(&stat, statbuf); 265} 266 267#if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT) 268SYSCALL_DEFINE4(newfstatat, int, dfd, const char __user *, filename, 269 struct stat __user *, statbuf, int, flag) 270{ 271 struct kstat stat; 272 int error; 273 274 error = vfs_fstatat(dfd, filename, &stat, flag); 275 if (error) 276 return error; 277 return cp_new_stat(&stat, statbuf); 278} 279#endif 280 281SYSCALL_DEFINE2(newfstat, unsigned int, fd, struct stat __user *, statbuf) 282{ 283 struct kstat stat; 284 int error = vfs_fstat(fd, &stat); 285 286 if (!error) 287 error = cp_new_stat(&stat, statbuf); 288 289 return error; 290} 291 292SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname, 293 char __user *, buf, int, bufsiz) 294{ 295 struct path path; 296 int error; 297 int empty = 0; 298 299 if (bufsiz <= 0) 300 return -EINVAL; 301 302 error = user_path_at_empty(dfd, pathname, LOOKUP_EMPTY, &path, &empty); 303 if (!error) { 304 struct inode *inode = path.dentry->d_inode; 305 306 error = empty ? -ENOENT : -EINVAL; 307 if (inode->i_op->readlink) { 308 error = security_inode_readlink(path.dentry); 309 if (!error) { 310 touch_atime(path.mnt, path.dentry); 311 error = inode->i_op->readlink(path.dentry, 312 buf, bufsiz); 313 } 314 } 315 path_put(&path); 316 } 317 return error; 318} 319 320SYSCALL_DEFINE3(readlink, const char __user *, path, char __user *, buf, 321 int, bufsiz) 322{ 323 return sys_readlinkat(AT_FDCWD, path, buf, bufsiz); 324} 325 326 327/* ---------- LFS-64 ----------- */ 328#ifdef __ARCH_WANT_STAT64 329 330static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf) 331{ 332 struct stat64 tmp; 333 334 memset(&tmp, 0, sizeof(struct stat64)); 335#ifdef CONFIG_MIPS 336 /* mips has weird padding, so we don't get 64 bits there */ 337 if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev)) 338 return -EOVERFLOW; 339 tmp.st_dev = new_encode_dev(stat->dev); 340 tmp.st_rdev = new_encode_dev(stat->rdev); 341#else 342 tmp.st_dev = huge_encode_dev(stat->dev); 343 tmp.st_rdev = huge_encode_dev(stat->rdev); 344#endif 345 tmp.st_ino = stat->ino; 346 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino) 347 return -EOVERFLOW; 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 367SYSCALL_DEFINE2(stat64, const char __user *, filename, 368 struct stat64 __user *, statbuf) 369{ 370 struct kstat stat; 371 int error = vfs_stat(filename, &stat); 372 373 if (!error) 374 error = cp_new_stat64(&stat, statbuf); 375 376 return error; 377} 378 379SYSCALL_DEFINE2(lstat64, const char __user *, filename, 380 struct stat64 __user *, statbuf) 381{ 382 struct kstat stat; 383 int error = vfs_lstat(filename, &stat); 384 385 if (!error) 386 error = cp_new_stat64(&stat, statbuf); 387 388 return error; 389} 390 391SYSCALL_DEFINE2(fstat64, unsigned long, fd, struct stat64 __user *, statbuf) 392{ 393 struct kstat stat; 394 int error = vfs_fstat(fd, &stat); 395 396 if (!error) 397 error = cp_new_stat64(&stat, statbuf); 398 399 return error; 400} 401 402SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename, 403 struct stat64 __user *, statbuf, int, flag) 404{ 405 struct kstat stat; 406 int error; 407 408 error = vfs_fstatat(dfd, filename, &stat, flag); 409 if (error) 410 return error; 411 return cp_new_stat64(&stat, statbuf); 412} 413#endif /* __ARCH_WANT_STAT64 */ 414 415/* Caller is here responsible for sufficient locking (ie. inode->i_lock) */ 416void __inode_add_bytes(struct inode *inode, loff_t bytes) 417{ 418 inode->i_blocks += bytes >> 9; 419 bytes &= 511; 420 inode->i_bytes += bytes; 421 if (inode->i_bytes >= 512) { 422 inode->i_blocks++; 423 inode->i_bytes -= 512; 424 } 425} 426 427void inode_add_bytes(struct inode *inode, loff_t bytes) 428{ 429 spin_lock(&inode->i_lock); 430 __inode_add_bytes(inode, bytes); 431 spin_unlock(&inode->i_lock); 432} 433 434EXPORT_SYMBOL(inode_add_bytes); 435 436void inode_sub_bytes(struct inode *inode, loff_t bytes) 437{ 438 spin_lock(&inode->i_lock); 439 inode->i_blocks -= bytes >> 9; 440 bytes &= 511; 441 if (inode->i_bytes < bytes) { 442 inode->i_blocks--; 443 inode->i_bytes += 512; 444 } 445 inode->i_bytes -= bytes; 446 spin_unlock(&inode->i_lock); 447} 448 449EXPORT_SYMBOL(inode_sub_bytes); 450 451loff_t inode_get_bytes(struct inode *inode) 452{ 453 loff_t ret; 454 455 spin_lock(&inode->i_lock); 456 ret = (((loff_t)inode->i_blocks) << 9) + inode->i_bytes; 457 spin_unlock(&inode->i_lock); 458 return ret; 459} 460 461EXPORT_SYMBOL(inode_get_bytes); 462 463void inode_set_bytes(struct inode *inode, loff_t bytes) 464{ 465 /* Caller is here responsible for sufficient locking 466 * (ie. inode->i_lock) */ 467 inode->i_blocks = bytes >> 9; 468 inode->i_bytes = bytes & 511; 469} 470 471EXPORT_SYMBOL(inode_set_bytes);