fs/stat.c

   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(char __user *name, struct kstat *stat)
  67 {
  68         struct nameidata nd;
  69         int error;
  70
  71         error = user_path_walk(name, &nd);
  72         if (!error) {
  73                 error = vfs_getattr(nd.mnt, nd.dentry, stat);
  74                 path_release(&nd);
  75         }
  76         return error;
  77 }
  78
  79 EXPORT_SYMBOL(vfs_stat);
  80
  81 int vfs_lstat(char __user *name, struct kstat *stat)
  82 {
  83         struct nameidata nd;
  84         int error;
  85
  86         error = user_path_walk_link(name, &nd);
  87         if (!error) {
  88                 error = vfs_getattr(nd.mnt, nd.dentry, stat);
  89                 path_release(&nd);
  90         }
  91         return error;
  92 }
  93
  94 EXPORT_SYMBOL(vfs_lstat);
  95
  96 int vfs_fstat(unsigned int fd, struct kstat *stat)
  97 {
  98         struct file *f = fget(fd);
  99         int error = -EBADF;
 100
 101         if (f) {
 102                 error = vfs_getattr(f->f_vfsmnt, f->f_dentry, stat);
 103                 fput(f);
 104         }
 105         return error;
 106 }
 107
 108 EXPORT_SYMBOL(vfs_fstat);
 109
 110 #ifdef __ARCH_WANT_OLD_STAT
 111
 112 /*
 113  * For backward compatibility?  Maybe this should be moved
 114  * into arch/i386 instead?
 115  */
 116 static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf)
 117 {
 118         static int warncount = 5;
 119         struct __old_kernel_stat tmp;
 120
 121         if (warncount > 0) {
 122                 warncount--;
 123                 printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n",
 124                         current->comm);
 125         } else if (warncount < 0) {
 126                 /* it's laughable, but... */
 127                 warncount = 0;
 128         }
 129
 130         memset(&tmp, 0, sizeof(struct __old_kernel_stat));
 131         tmp.st_dev = old_encode_dev(stat->dev);
 132         tmp.st_ino = stat->ino;
 133         tmp.st_mode = stat->mode;
 134         tmp.st_nlink = stat->nlink;
 135         if (tmp.st_nlink != stat->nlink)
 136                 return -EOVERFLOW;
 137         SET_UID(tmp.st_uid, stat->uid);
 138         SET_GID(tmp.st_gid, stat->gid);
 139         tmp.st_rdev = old_encode_dev(stat->rdev);
 140 #if BITS_PER_LONG == 32
 141         if (stat->size > MAX_NON_LFS)
 142                 return -EOVERFLOW;
 143 #endif
 144         tmp.st_size = stat->size;
 145         tmp.st_atime = stat->atime.tv_sec;
 146         tmp.st_mtime = stat->mtime.tv_sec;
 147         tmp.st_ctime = stat->ctime.tv_sec;
 148         return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
 149 }
 150
 151 asmlinkage long sys_stat(char __user * filename, struct __old_kernel_stat __user * statbuf)
 152 {
 153         struct kstat stat;
 154         int error = vfs_stat(filename, &stat);
 155
 156         if (!error)
 157                 error = cp_old_stat(&stat, statbuf);
 158
 159         return error;
 160 }
 161 asmlinkage long sys_lstat(char __user * filename, struct __old_kernel_stat __user * statbuf)
 162 {
 163         struct kstat stat;
 164         int error = vfs_lstat(filename, &stat);
 165
 166         if (!error)
 167                 error = cp_old_stat(&stat, statbuf);
 168
 169         return error;
 170 }
 171 asmlinkage long sys_fstat(unsigned int fd, struct __old_kernel_stat __user * statbuf)
 172 {
 173         struct kstat stat;
 174         int error = vfs_fstat(fd, &stat);
 175
 176         if (!error)
 177                 error = cp_old_stat(&stat, statbuf);
 178
 179         return error;
 180 }
 181
 182 #endif /* __ARCH_WANT_OLD_STAT */
 183
 184 static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf)
 185 {
 186         struct stat tmp;
 187
 188 #if BITS_PER_LONG == 32
 189         if (!old_valid_dev(stat->dev) || !old_valid_dev(stat->rdev))
 190                 return -EOVERFLOW;
 191 #else
 192         if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev))
 193                 return -EOVERFLOW;
 194 #endif
 195
 196         memset(&tmp, 0, sizeof(tmp));
 197 #if BITS_PER_LONG == 32
 198         tmp.st_dev = old_encode_dev(stat->dev);
 199 #else
 200         tmp.st_dev = new_encode_dev(stat->dev);
 201 #endif
 202         tmp.st_ino = stat->ino;
 203         tmp.st_mode = stat->mode;
 204         tmp.st_nlink = stat->nlink;
 205         if (tmp.st_nlink != stat->nlink)
 206                 return -EOVERFLOW;
 207         SET_UID(tmp.st_uid, stat->uid);
 208         SET_GID(tmp.st_gid, stat->gid);
 209 #if BITS_PER_LONG == 32
 210         tmp.st_rdev = old_encode_dev(stat->rdev);
 211 #else
 212         tmp.st_rdev = new_encode_dev(stat->rdev);
 213 #endif
 214 #if BITS_PER_LONG == 32
 215         if (stat->size > MAX_NON_LFS)
 216                 return -EOVERFLOW;
 217 #endif
 218         tmp.st_size = stat->size;
 219         tmp.st_atime = stat->atime.tv_sec;
 220         tmp.st_mtime = stat->mtime.tv_sec;
 221         tmp.st_ctime = stat->ctime.tv_sec;
 222 #ifdef STAT_HAVE_NSEC
 223         tmp.st_atime_nsec = stat->atime.tv_nsec;
 224         tmp.st_mtime_nsec = stat->mtime.tv_nsec;
 225         tmp.st_ctime_nsec = stat->ctime.tv_nsec;
 226 #endif
 227         tmp.st_blocks = stat->blocks;
 228         tmp.st_blksize = stat->blksize;
 229         return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
 230 }
 231
 232 asmlinkage long sys_newstat(char __user * filename, struct stat __user * statbuf)
 233 {
 234         struct kstat stat;
 235         int error = vfs_stat(filename, &stat);
 236
 237         if (!error)
 238                 error = cp_new_stat(&stat, statbuf);
 239
 240         return error;
 241 }
 242 asmlinkage long sys_newlstat(char __user * filename, struct stat __user * statbuf)
 243 {
 244         struct kstat stat;
 245         int error = vfs_lstat(filename, &stat);
 246
 247         if (!error)
 248                 error = cp_new_stat(&stat, statbuf);
 249
 250         return error;
 251 }
 252 asmlinkage long sys_newfstat(unsigned int fd, struct stat __user * statbuf)
 253 {
 254         struct kstat stat;
 255         int error = vfs_fstat(fd, &stat);
 256
 257         if (!error)
 258                 error = cp_new_stat(&stat, statbuf);
 259
 260         return error;
 261 }
 262
 263 asmlinkage long sys_readlink(const char __user * path, char __user * buf, int bufsiz)
 264 {
 265         struct nameidata nd;
 266         int error;
 267
 268         if (bufsiz <= 0)
 269                 return -EINVAL;
 270
 271         error = user_path_walk_link(path, &nd);
 272         if (!error) {
 273                 struct inode * inode = nd.dentry->d_inode;
 274
 275                 error = -EINVAL;
 276                 if (inode->i_op && inode->i_op->readlink) {
 277                         error = security_inode_readlink(nd.dentry);
 278                         if (!error) {
 279                                 touch_atime(nd.mnt, nd.dentry);
 280                                 error = inode->i_op->readlink(nd.dentry, buf, bufsiz);
 281                         }
 282                 }
 283                 path_release(&nd);
 284         }
 285         return error;
 286 }
 287
 288
 289 /* ---------- LFS-64 ----------- */
 290 #ifdef __ARCH_WANT_STAT64
 291
 292 static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf)
 293 {
 294         struct stat64 tmp;
 295
 296         memset(&tmp, 0, sizeof(struct stat64));
 297 #ifdef CONFIG_MIPS
 298         /* mips has weird padding, so we don't get 64 bits there */
 299         if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev))
 300                 return -EOVERFLOW;
 301         tmp.st_dev = new_encode_dev(stat->dev);
 302         tmp.st_rdev = new_encode_dev(stat->rdev);
 303 #else
 304         tmp.st_dev = huge_encode_dev(stat->dev);
 305         tmp.st_rdev = huge_encode_dev(stat->rdev);
 306 #endif
 307         tmp.st_ino = stat->ino;
 308 #ifdef STAT64_HAS_BROKEN_ST_INO
 309         tmp.__st_ino = stat->ino;
 310 #endif
 311         tmp.st_mode = stat->mode;
 312         tmp.st_nlink = stat->nlink;
 313         tmp.st_uid = stat->uid;
 314         tmp.st_gid = stat->gid;
 315         tmp.st_atime = stat->atime.tv_sec;
 316         tmp.st_atime_nsec = stat->atime.tv_nsec;
 317         tmp.st_mtime = stat->mtime.tv_sec;
 318         tmp.st_mtime_nsec = stat->mtime.tv_nsec;
 319         tmp.st_ctime = stat->ctime.tv_sec;
 320         tmp.st_ctime_nsec = stat->ctime.tv_nsec;
 321         tmp.st_size = stat->size;
 322         tmp.st_blocks = stat->blocks;
 323         tmp.st_blksize = stat->blksize;
 324         return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
 325 }
 326
 327 asmlinkage long sys_stat64(char __user * filename, struct stat64 __user * statbuf)
 328 {
 329         struct kstat stat;
 330         int error = vfs_stat(filename, &stat);
 331
 332         if (!error)
 333                 error = cp_new_stat64(&stat, statbuf);
 334
 335         return error;
 336 }
 337 asmlinkage long sys_lstat64(char __user * filename, struct stat64 __user * statbuf)
 338 {
 339         struct kstat stat;
 340         int error = vfs_lstat(filename, &stat);
 341
 342         if (!error)
 343                 error = cp_new_stat64(&stat, statbuf);
 344
 345         return error;
 346 }
 347 asmlinkage long sys_fstat64(unsigned long fd, struct stat64 __user * statbuf)
 348 {
 349         struct kstat stat;
 350         int error = vfs_fstat(fd, &stat);
 351
 352         if (!error)
 353                 error = cp_new_stat64(&stat, statbuf);
 354
 355         return error;
 356 }
 357
 358 #endif /* __ARCH_WANT_STAT64 */
 359
 360 void inode_add_bytes(struct inode *inode, loff_t bytes)
 361 {
 362         spin_lock(&inode->i_lock);
 363         inode->i_blocks += bytes >> 9;
 364         bytes &= 511;
 365         inode->i_bytes += bytes;
 366         if (inode->i_bytes >= 512) {
 367                 inode->i_blocks++;
 368                 inode->i_bytes -= 512;
 369         }
 370         spin_unlock(&inode->i_lock);
 371 }
 372
 373 EXPORT_SYMBOL(inode_add_bytes);
 374
 375 void inode_sub_bytes(struct inode *inode, loff_t bytes)
 376 {
 377         spin_lock(&inode->i_lock);
 378         inode->i_blocks -= bytes >> 9;
 379         bytes &= 511;
 380         if (inode->i_bytes < bytes) {
 381                 inode->i_blocks--;
 382                 inode->i_bytes += 512;
 383         }
 384         inode->i_bytes -= bytes;
 385         spin_unlock(&inode->i_lock);
 386 }
 387
 388 EXPORT_SYMBOL(inode_sub_bytes);
 389
 390 loff_t inode_get_bytes(struct inode *inode)
 391 {
 392         loff_t ret;
 393
 394         spin_lock(&inode->i_lock);
 395         ret = (((loff_t)inode->i_blocks) << 9) + inode->i_bytes;
 396         spin_unlock(&inode->i_lock);
 397         return ret;
 398 }
 399
 400 EXPORT_SYMBOL(inode_get_bytes);
 401
 402 void inode_set_bytes(struct inode *inode, loff_t bytes)
 403 {
 404         /* Caller is here responsible for sufficient locking
 405          * (ie. inode->i_lock) */
 406         inode->i_blocks = bytes >> 9;
 407         inode->i_bytes = bytes & 511;
 408 }
 409
 410 EXPORT_SYMBOL(inode_set_bytes);