/*
   *  linux/fs/stat.c
   *
   *  Copyright (C) 1991, 1992  Linus Torvalds
   */

  #include <linux/export.h>

  #include <linux/mm.h>
  #include <linux/errno.h>
  #include <linux/file.h>

  #include <linux/highuid.h>
  #include <linux/fs.h>
  #include <linux/namei.h>
  #include <linux/security.h>
  #include <linux/syscalls.h>

  #include <linux/pagemap.h>

  
  #include <asm/uaccess.h>
  #include <asm/unistd.h>
  
  void generic_fillattr(struct inode *inode, struct kstat *stat)
  {
  	stat->dev = inode->i_sb->s_dev;
  	stat->ino = inode->i_ino;
  	stat->mode = inode->i_mode;
  	stat->nlink = inode->i_nlink;
  	stat->uid = inode->i_uid;
  	stat->gid = inode->i_gid;
  	stat->rdev = inode->i_rdev;

  	stat->size = i_size_read(inode);

  	stat->atime = inode->i_atime;
  	stat->mtime = inode->i_mtime;
  	stat->ctime = inode->i_ctime;

  	stat->blksize = (1 << inode->i_blkbits);

  	stat->blocks = inode->i_blocks;

  }
  
  EXPORT_SYMBOL(generic_fillattr);

  /**
   * vfs_getattr_nosec - getattr without security checks
   * @path: file to get attributes from
   * @stat: structure to return attributes in
   *
   * Get attributes without calling security_inode_getattr.
   *
   * Currently the only caller other than vfs_getattr is internal to the
   * filehandle lookup code, which uses only the inode number and returns
   * no attributes to any user.  Any other code probably wants
   * vfs_getattr.
   */
  int vfs_getattr_nosec(struct path *path, struct kstat *stat)

  {

  	struct inode *inode = d_backing_inode(path->dentry);

  
  	if (inode->i_op->getattr)

  		return inode->i_op->getattr(path->mnt, path->dentry, stat);

  
  	generic_fillattr(inode, stat);

  	return 0;
  }

  EXPORT_SYMBOL(vfs_getattr_nosec);
  
  int vfs_getattr(struct path *path, struct kstat *stat)
  {
  	int retval;

  	retval = security_inode_getattr(path);

  	if (retval)
  		return retval;
  	return vfs_getattr_nosec(path, stat);
  }

  EXPORT_SYMBOL(vfs_getattr);

  int vfs_fstat(unsigned int fd, struct kstat *stat)
  {

  	struct fd f = fdget_raw(fd);

  	int error = -EBADF;

  	if (f.file) {

  		error = vfs_getattr(&f.file->f_path, stat);

  		fdput(f);

  	}
  	return error;
  }

  EXPORT_SYMBOL(vfs_fstat);

  int vfs_fstatat(int dfd, const char __user *filename, struct kstat *stat,
  		int flag)

  {

  	struct path path;

  	int error = -EINVAL;

  	unsigned int lookup_flags = 0;

  	if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT |
  		      AT_EMPTY_PATH)) != 0)

  		goto out;

  	if (!(flag & AT_SYMLINK_NOFOLLOW))
  		lookup_flags |= LOOKUP_FOLLOW;

  	if (flag & AT_EMPTY_PATH)
  		lookup_flags |= LOOKUP_EMPTY;

  retry:

  	error = user_path_at(dfd, filename, lookup_flags, &path);
  	if (error)
  		goto out;

  	error = vfs_getattr(&path, stat);

  	path_put(&path);

  	if (retry_estale(error, lookup_flags)) {
  		lookup_flags |= LOOKUP_REVAL;
  		goto retry;
  	}

  out:
  	return error;
  }

  EXPORT_SYMBOL(vfs_fstatat);

  int vfs_stat(const char __user *name, struct kstat *stat)

  {
  	return vfs_fstatat(AT_FDCWD, name, stat, 0);
  }
  EXPORT_SYMBOL(vfs_stat);

  int vfs_lstat(const char __user *name, struct kstat *stat)

  {
  	return vfs_fstatat(AT_FDCWD, name, stat, AT_SYMLINK_NOFOLLOW);
  }
  EXPORT_SYMBOL(vfs_lstat);

  #ifdef __ARCH_WANT_OLD_STAT
  
  /*
   * For backward compatibility?  Maybe this should be moved
   * into arch/i386 instead?
   */
  static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf)
  {
  	static int warncount = 5;
  	struct __old_kernel_stat tmp;
  	
  	if (warncount > 0) {
  		warncount--;
  		printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.
  ",
  			current->comm);
  	} else if (warncount < 0) {
  		/* it's laughable, but... */
  		warncount = 0;
  	}
  
  	memset(&tmp, 0, sizeof(struct __old_kernel_stat));
  	tmp.st_dev = old_encode_dev(stat->dev);
  	tmp.st_ino = stat->ino;

  	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
  		return -EOVERFLOW;

  	tmp.st_mode = stat->mode;
  	tmp.st_nlink = stat->nlink;
  	if (tmp.st_nlink != stat->nlink)
  		return -EOVERFLOW;

  	SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
  	SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));

  	tmp.st_rdev = old_encode_dev(stat->rdev);
  #if BITS_PER_LONG == 32
  	if (stat->size > MAX_NON_LFS)
  		return -EOVERFLOW;
  #endif	
  	tmp.st_size = stat->size;
  	tmp.st_atime = stat->atime.tv_sec;
  	tmp.st_mtime = stat->mtime.tv_sec;
  	tmp.st_ctime = stat->ctime.tv_sec;
  	return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
  }

  SYSCALL_DEFINE2(stat, const char __user *, filename,
  		struct __old_kernel_stat __user *, statbuf)

  {
  	struct kstat stat;

  	int error;

  	error = vfs_stat(filename, &stat);
  	if (error)
  		return error;

  	return cp_old_stat(&stat, statbuf);

  }

  SYSCALL_DEFINE2(lstat, const char __user *, filename,
  		struct __old_kernel_stat __user *, statbuf)

  {
  	struct kstat stat;

  	int error;

  	error = vfs_lstat(filename, &stat);
  	if (error)
  		return error;

  	return cp_old_stat(&stat, statbuf);

  }

  
  SYSCALL_DEFINE2(fstat, unsigned int, fd, struct __old_kernel_stat __user *, statbuf)

  {
  	struct kstat stat;
  	int error = vfs_fstat(fd, &stat);
  
  	if (!error)
  		error = cp_old_stat(&stat, statbuf);
  
  	return error;
  }
  
  #endif /* __ARCH_WANT_OLD_STAT */

  #if BITS_PER_LONG == 32
  #  define choose_32_64(a,b) a
  #else
  #  define choose_32_64(a,b) b
  #endif

  #define valid_dev(x)  choose_32_64(old_valid_dev(x),true)

  #define encode_dev(x) choose_32_64(old_encode_dev,new_encode_dev)(x)

  #ifndef INIT_STRUCT_STAT_PADDING
  #  define INIT_STRUCT_STAT_PADDING(st) memset(&st, 0, sizeof(st))
  #endif

  static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf)
  {
  	struct stat tmp;

  	if (!valid_dev(stat->dev) || !valid_dev(stat->rdev))

  		return -EOVERFLOW;

  #if BITS_PER_LONG == 32
  	if (stat->size > MAX_NON_LFS)

  		return -EOVERFLOW;
  #endif

  	INIT_STRUCT_STAT_PADDING(tmp);

  	tmp.st_dev = encode_dev(stat->dev);

  	tmp.st_ino = stat->ino;

  	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
  		return -EOVERFLOW;

  	tmp.st_mode = stat->mode;
  	tmp.st_nlink = stat->nlink;
  	if (tmp.st_nlink != stat->nlink)
  		return -EOVERFLOW;

  	SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
  	SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));

  	tmp.st_rdev = encode_dev(stat->rdev);

  	tmp.st_size = stat->size;
  	tmp.st_atime = stat->atime.tv_sec;
  	tmp.st_mtime = stat->mtime.tv_sec;
  	tmp.st_ctime = stat->ctime.tv_sec;
  #ifdef STAT_HAVE_NSEC
  	tmp.st_atime_nsec = stat->atime.tv_nsec;
  	tmp.st_mtime_nsec = stat->mtime.tv_nsec;
  	tmp.st_ctime_nsec = stat->ctime.tv_nsec;
  #endif
  	tmp.st_blocks = stat->blocks;
  	tmp.st_blksize = stat->blksize;
  	return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
  }

  SYSCALL_DEFINE2(newstat, const char __user *, filename,
  		struct stat __user *, statbuf)

  {
  	struct kstat stat;

  	int error = vfs_stat(filename, &stat);

  	if (error)
  		return error;
  	return cp_new_stat(&stat, statbuf);

  }

  SYSCALL_DEFINE2(newlstat, const char __user *, filename,
  		struct stat __user *, statbuf)

  {
  	struct kstat stat;

  	int error;

  	error = vfs_lstat(filename, &stat);
  	if (error)
  		return error;

  	return cp_new_stat(&stat, statbuf);

  }

  #if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT)

  SYSCALL_DEFINE4(newfstatat, int, dfd, const char __user *, filename,

  		struct stat __user *, statbuf, int, flag)

  {
  	struct kstat stat;

  	int error;

  	error = vfs_fstatat(dfd, filename, &stat, flag);
  	if (error)
  		return error;
  	return cp_new_stat(&stat, statbuf);

  }

  #endif

  SYSCALL_DEFINE2(newfstat, unsigned int, fd, struct stat __user *, statbuf)

  {
  	struct kstat stat;
  	int error = vfs_fstat(fd, &stat);
  
  	if (!error)
  		error = cp_new_stat(&stat, statbuf);
  
  	return error;
  }

  SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
  		char __user *, buf, int, bufsiz)

  {

  	struct path path;

  	int error;

  	int empty = 0;

  	unsigned int lookup_flags = LOOKUP_EMPTY;

  
  	if (bufsiz <= 0)
  		return -EINVAL;

  retry:
  	error = user_path_at_empty(dfd, pathname, lookup_flags, &path, &empty);

  	if (!error) {

  		struct inode *inode = d_backing_inode(path.dentry);

  		error = empty ? -ENOENT : -EINVAL;

  		if (inode->i_op->readlink) {

  			error = security_inode_readlink(path.dentry);

  			if (!error) {

  				touch_atime(&path);

  				error = inode->i_op->readlink(path.dentry,

  							      buf, bufsiz);

  			}
  		}

  		path_put(&path);

  		if (retry_estale(error, lookup_flags)) {
  			lookup_flags |= LOOKUP_REVAL;
  			goto retry;
  		}

  	}
  	return error;
  }

  SYSCALL_DEFINE3(readlink, const char __user *, path, char __user *, buf,
  		int, bufsiz)

  {
  	return sys_readlinkat(AT_FDCWD, path, buf, bufsiz);
  }

  
  /* ---------- LFS-64 ----------- */

  #if defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_COMPAT_STAT64)

  #ifndef INIT_STRUCT_STAT64_PADDING
  #  define INIT_STRUCT_STAT64_PADDING(st) memset(&st, 0, sizeof(st))
  #endif

  static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf)
  {
  	struct stat64 tmp;

  	INIT_STRUCT_STAT64_PADDING(tmp);

  #ifdef CONFIG_MIPS
  	/* mips has weird padding, so we don't get 64 bits there */

  	tmp.st_dev = new_encode_dev(stat->dev);
  	tmp.st_rdev = new_encode_dev(stat->rdev);
  #else
  	tmp.st_dev = huge_encode_dev(stat->dev);
  	tmp.st_rdev = huge_encode_dev(stat->rdev);
  #endif
  	tmp.st_ino = stat->ino;

  	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
  		return -EOVERFLOW;

  #ifdef STAT64_HAS_BROKEN_ST_INO
  	tmp.__st_ino = stat->ino;
  #endif
  	tmp.st_mode = stat->mode;
  	tmp.st_nlink = stat->nlink;

  	tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid);
  	tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid);

  	tmp.st_atime = stat->atime.tv_sec;
  	tmp.st_atime_nsec = stat->atime.tv_nsec;
  	tmp.st_mtime = stat->mtime.tv_sec;
  	tmp.st_mtime_nsec = stat->mtime.tv_nsec;
  	tmp.st_ctime = stat->ctime.tv_sec;
  	tmp.st_ctime_nsec = stat->ctime.tv_nsec;
  	tmp.st_size = stat->size;
  	tmp.st_blocks = stat->blocks;
  	tmp.st_blksize = stat->blksize;
  	return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
  }

  SYSCALL_DEFINE2(stat64, const char __user *, filename,
  		struct stat64 __user *, statbuf)

  {
  	struct kstat stat;
  	int error = vfs_stat(filename, &stat);
  
  	if (!error)
  		error = cp_new_stat64(&stat, statbuf);
  
  	return error;
  }

  SYSCALL_DEFINE2(lstat64, const char __user *, filename,
  		struct stat64 __user *, statbuf)

  {
  	struct kstat stat;
  	int error = vfs_lstat(filename, &stat);
  
  	if (!error)
  		error = cp_new_stat64(&stat, statbuf);
  
  	return error;
  }

  
  SYSCALL_DEFINE2(fstat64, unsigned long, fd, struct stat64 __user *, statbuf)

  {
  	struct kstat stat;
  	int error = vfs_fstat(fd, &stat);
  
  	if (!error)
  		error = cp_new_stat64(&stat, statbuf);
  
  	return error;
  }

  SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename,

  		struct stat64 __user *, statbuf, int, flag)

  {
  	struct kstat stat;

  	int error;

  	error = vfs_fstatat(dfd, filename, &stat, flag);
  	if (error)
  		return error;
  	return cp_new_stat64(&stat, statbuf);

  }

  #endif /* __ARCH_WANT_STAT64 || __ARCH_WANT_COMPAT_STAT64 */

  /* Caller is here responsible for sufficient locking (ie. inode->i_lock) */
  void __inode_add_bytes(struct inode *inode, loff_t bytes)

  {

  	inode->i_blocks += bytes >> 9;
  	bytes &= 511;
  	inode->i_bytes += bytes;
  	if (inode->i_bytes >= 512) {
  		inode->i_blocks++;
  		inode->i_bytes -= 512;
  	}

  }
  
  void inode_add_bytes(struct inode *inode, loff_t bytes)
  {
  	spin_lock(&inode->i_lock);
  	__inode_add_bytes(inode, bytes);

  	spin_unlock(&inode->i_lock);
  }
  
  EXPORT_SYMBOL(inode_add_bytes);

  void __inode_sub_bytes(struct inode *inode, loff_t bytes)

  {

  	inode->i_blocks -= bytes >> 9;
  	bytes &= 511;
  	if (inode->i_bytes < bytes) {
  		inode->i_blocks--;
  		inode->i_bytes += 512;
  	}
  	inode->i_bytes -= bytes;

  }
  
  EXPORT_SYMBOL(__inode_sub_bytes);
  
  void inode_sub_bytes(struct inode *inode, loff_t bytes)
  {
  	spin_lock(&inode->i_lock);
  	__inode_sub_bytes(inode, bytes);

  	spin_unlock(&inode->i_lock);
  }
  
  EXPORT_SYMBOL(inode_sub_bytes);
  
  loff_t inode_get_bytes(struct inode *inode)
  {
  	loff_t ret;
  
  	spin_lock(&inode->i_lock);
  	ret = (((loff_t)inode->i_blocks) << 9) + inode->i_bytes;
  	spin_unlock(&inode->i_lock);
  	return ret;
  }
  
  EXPORT_SYMBOL(inode_get_bytes);
  
  void inode_set_bytes(struct inode *inode, loff_t bytes)
  {
  	/* Caller is here responsible for sufficient locking
  	 * (ie. inode->i_lock) */
  	inode->i_blocks = bytes >> 9;
  	inode->i_bytes = bytes & 511;
  }
  
  EXPORT_SYMBOL(inode_set_bytes);