/* *  linux/fs/readdir.c * *  Copyright (C) 1995  Linus Torvalds */ #include <linux/stddef.h>#include <linux/kernel.h>#include <linux/module.h>#include <linux/time.h>#include <linux/mm.h>#include <linux/errno.h>#include <linux/stat.h>#include <linux/file.h>#include <linux/fs.h>#include <linux/dirent.h>#include <linux/security.h>#include <linux/syscalls.h>#include <linux/unistd.h> #include <asm/uaccess.h> int vfs_readdir(struct file *file, filldir_t filler, void *buf){	struct inode *inode = file->f_path.dentry->d_inode;	int res = -ENOTDIR;	if (!file->f_op || !file->f_op->readdir)		goto out; 	res = security_file_permission(file, MAY_READ);	if (res)		goto out; 	res = mutex_lock_killable(&inode->i_mutex);	if (res)		goto out; 	res = -ENOENT;	if (!IS_DEADDIR(inode)) {		res = file->f_op->readdir(file, buf, filler);		file_accessed(file);	}	mutex_unlock(&inode->i_mutex);out:	return res;} EXPORT_SYMBOL(vfs_readdir); /* * Traditional linux readdir() handling.. * * "count=1" is a special case, meaning that the buffer is one * dirent-structure in size and that the code can't handle more * anyway. Thus the special "fillonedir()" function for that * case (the low-level handlers don't need to care about this). */ #ifdef __ARCH_WANT_OLD_READDIR struct old_linux_dirent {	unsigned long	d_ino;	unsigned long	d_offset;	unsigned short	d_namlen;	char		d_name[1];}; struct readdir_callback {	struct old_linux_dirent __user * dirent;	int result;}; static int fillonedir(void * __buf, const char * name, int namlen, loff_t offset,		      u64 ino, unsigned int d_type){	struct readdir_callback * buf = (struct readdir_callback *) __buf;	struct old_linux_dirent __user * dirent;	unsigned long d_ino; 	if (buf->result)		return -EINVAL;	d_ino = ino;	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {		buf->result = -EOVERFLOW;		return -EOVERFLOW;	}	buf->result++;	dirent = buf->dirent;	if (!access_ok(VERIFY_WRITE, dirent,			(unsigned long)(dirent->d_name + namlen + 1) -				(unsigned long)dirent))		goto efault;	if (	__put_user(d_ino, &dirent->d_ino) ||		__put_user(offset, &dirent->d_offset) ||		__put_user(namlen, &dirent->d_namlen) ||		__copy_to_user(dirent->d_name, name, namlen) ||		__put_user(0, dirent->d_name + namlen))		goto efault;	return 0;efault:	buf->result = -EFAULT;	return -EFAULT;} SYSCALL_DEFINE3(old_readdir, unsigned int, fd,		struct old_linux_dirent __user *, dirent, unsigned int, count){	int error;	struct file * file;	struct readdir_callback buf; 	error = -EBADF;	file = fget(fd);	if (!file)		goto out; 	buf.result = 0;	buf.dirent = dirent; 	error = vfs_readdir(file, fillonedir, &buf);	if (buf.result)		error = buf.result; 	fput(file);out:	return error;} #endif /* __ARCH_WANT_OLD_READDIR */ /* * New, all-improved, singing, dancing, iBCS2-compliant getdents() * interface.  */struct linux_dirent {	unsigned long	d_ino;	unsigned long	d_off;	unsigned short	d_reclen;	char		d_name[1];}; struct getdents_callback {	struct linux_dirent __user * current_dir;	struct linux_dirent __user * previous;	int count;	int error;}; static int filldir(void * __buf, const char * name, int namlen, loff_t offset,		   u64 ino, unsigned int d_type){	struct linux_dirent __user * dirent;	struct getdents_callback * buf = (struct getdents_callback *) __buf;	unsigned long d_ino;	int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2,		sizeof(long)); 	buf->error = -EINVAL;	/* only used if we fail.. */	if (reclen > buf->count)		return -EINVAL;	d_ino = ino;	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {		buf->error = -EOVERFLOW;		return -EOVERFLOW;	}	dirent = buf->previous;	if (dirent) {		if (__put_user(offset, &dirent->d_off))			goto efault;	}	dirent = buf->current_dir;	if (__put_user(d_ino, &dirent->d_ino))		goto efault;	if (__put_user(reclen, &dirent->d_reclen))		goto efault;	if (copy_to_user(dirent->d_name, name, namlen))		goto efault;	if (__put_user(0, dirent->d_name + namlen))		goto efault;	if (__put_user(d_type, (char __user *) dirent + reclen - 1))		goto efault;	buf->previous = dirent;	dirent = (void __user *)dirent + reclen;	buf->current_dir = dirent;	buf->count -= reclen;	return 0;efault:	buf->error = -EFAULT;	return -EFAULT;} SYSCALL_DEFINE3(getdents, unsigned int, fd,		struct linux_dirent __user *, dirent, unsigned int, count){	struct file * file;	struct linux_dirent __user * lastdirent;	struct getdents_callback buf;	int error; 	error = -EFAULT;	if (!access_ok(VERIFY_WRITE, dirent, count))		goto out; 	error = -EBADF;	file = fget(fd);	if (!file)		goto out; 	buf.current_dir = dirent;	buf.previous = NULL;	buf.count = count;	buf.error = 0; 	error = vfs_readdir(file, filldir, &buf);	if (error >= 0)		error = buf.error;	lastdirent = buf.previous;	if (lastdirent) {		if (put_user(file->f_pos, &lastdirent->d_off))			error = -EFAULT;		else			error = count - buf.count;	}	fput(file);out:	return error;} struct getdents_callback64 {	struct linux_dirent64 __user * current_dir;	struct linux_dirent64 __user * previous;	int count;	int error;}; static int filldir64(void * __buf, const char * name, int namlen, loff_t offset,		     u64 ino, unsigned int d_type){	struct linux_dirent64 __user *dirent;	struct getdents_callback64 * buf = (struct getdents_callback64 *) __buf;	int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,		sizeof(u64)); 	buf->error = -EINVAL;	/* only used if we fail.. */	if (reclen > buf->count)		return -EINVAL;	dirent = buf->previous;	if (dirent) {		if (__put_user(offset, &dirent->d_off))			goto efault;	}	dirent = buf->current_dir;	if (__put_user(ino, &dirent->d_ino))		goto efault;	if (__put_user(0, &dirent->d_off))		goto efault;	if (__put_user(reclen, &dirent->d_reclen))		goto efault;	if (__put_user(d_type, &dirent->d_type))		goto efault;	if (copy_to_user(dirent->d_name, name, namlen))		goto efault;	if (__put_user(0, dirent->d_name + namlen))		goto efault;	buf->previous = dirent;	dirent = (void __user *)dirent + reclen;	buf->current_dir = dirent;	buf->count -= reclen;	return 0;efault:	buf->error = -EFAULT;	return -EFAULT;} SYSCALL_DEFINE3(getdents64, unsigned int, fd,		struct linux_dirent64 __user *, dirent, unsigned int, count){	struct file * file;	struct linux_dirent64 __user * lastdirent;	struct getdents_callback64 buf;	int error; 	error = -EFAULT;	if (!access_ok(VERIFY_WRITE, dirent, count))		goto out; 	error = -EBADF;	file = fget(fd);	if (!file)		goto out; 	buf.current_dir = dirent;	buf.previous = NULL;	buf.count = count;	buf.error = 0; 	error = vfs_readdir(file, filldir64, &buf);	if (error >= 0)		error = buf.error;	lastdirent = buf.previous;	if (lastdirent) {		typeof(lastdirent->d_off) d_off = file->f_pos;		if (__put_user(d_off, &lastdirent->d_off))			error = -EFAULT;		else			error = count - buf.count;	}	fput(file);out:	return error;}