/* *  linux/fs/stat.c * *  Copyright (C) 1991, 1992  Linus Torvalds */ #include <linux/module.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); int vfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat){	struct inode *inode = dentry->d_inode;	int retval; 	retval = security_inode_getattr(mnt, dentry);	if (retval)		return retval; 	if (inode->i_op->getattr)		return inode->i_op->getattr(mnt, dentry, stat); 	generic_fillattr(inode, stat);	return 0;} EXPORT_SYMBOL(vfs_getattr); int vfs_fstat(unsigned int fd, struct kstat *stat){	struct file *f = fget(fd);	int error = -EBADF; 	if (f) {		error = vfs_getattr(f->f_path.mnt, f->f_path.dentry, stat);		fput(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;	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; 	error = user_path_at(dfd, filename, lookup_flags, &path);	if (error)		goto out; 	error = vfs_getattr(path.mnt, path.dentry, stat);	path_put(&path);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.\n",			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, stat->uid);	SET_GID(tmp.st_gid, 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 */ static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf){	struct stat tmp; #if BITS_PER_LONG == 32	if (!old_valid_dev(stat->dev) || !old_valid_dev(stat->rdev))		return -EOVERFLOW;#else	if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev))		return -EOVERFLOW;#endif 	memset(&tmp, 0, sizeof(tmp));#if BITS_PER_LONG == 32	tmp.st_dev = old_encode_dev(stat->dev);#else	tmp.st_dev = new_encode_dev(stat->dev);#endif	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, stat->uid);	SET_GID(tmp.st_gid, stat->gid);#if BITS_PER_LONG == 32	tmp.st_rdev = old_encode_dev(stat->rdev);#else	tmp.st_rdev = new_encode_dev(stat->rdev);#endif#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;#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; 	if (bufsiz <= 0)		return -EINVAL; 	error = user_path_at_empty(dfd, pathname, LOOKUP_EMPTY, &path, &empty);	if (!error) {		struct inode *inode = path.dentry->d_inode; 		error = empty ? -ENOENT : -EINVAL;		if (inode->i_op->readlink) {			error = security_inode_readlink(path.dentry);			if (!error) {				touch_atime(path.mnt, path.dentry);				error = inode->i_op->readlink(path.dentry,							      buf, bufsiz);			}		}		path_put(&path);	}	return error;} SYSCALL_DEFINE3(readlink, const char __user *, path, char __user *, buf,		int, bufsiz){	return sys_readlinkat(AT_FDCWD, path, buf, bufsiz);}  /* ---------- LFS-64 ----------- */#ifdef __ARCH_WANT_STAT64 static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf){	struct stat64 tmp; 	memset(&tmp, 0, sizeof(struct stat64));#ifdef CONFIG_MIPS	/* mips has weird padding, so we don't get 64 bits there */	if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev))		return -EOVERFLOW;	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 = stat->uid;	tmp.st_gid = 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 */ /* 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){	spin_lock(&inode->i_lock);	inode->i_blocks -= bytes >> 9;	bytes &= 511;	if (inode->i_bytes < bytes) {		inode->i_blocks--;		inode->i_bytes += 512;	}	inode->i_bytes -= 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);