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/*
* linux/fs/stat.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <asm/uaccess.h>
/*
* Revalidate the inode. This is required for proper NFS attribute caching.
*/
static __inline__ int
do_revalidate(struct inode *inode)
{
if (inode->i_op && inode->i_op->revalidate)
return inode->i_op->revalidate(inode);
return 0;
}
#if !defined(__alpha__) && !defined(__sparc__)
/*
* For backward compatibility? Maybe this should be moved
* into arch/i386 instead?
*/
static int cp_old_stat(struct inode * inode, struct __old_kernel_stat * statbuf)
{
struct __old_kernel_stat tmp;
printk("VFS: Warning: %s using old stat() call. Recompile your binary.\n",
current->comm);
tmp.st_dev = kdev_t_to_nr(inode->i_dev);
tmp.st_ino = inode->i_ino;
tmp.st_mode = inode->i_mode;
tmp.st_nlink = inode->i_nlink;
tmp.st_uid = inode->i_uid;
tmp.st_gid = inode->i_gid;
tmp.st_rdev = kdev_t_to_nr(inode->i_rdev);
tmp.st_size = inode->i_size;
tmp.st_atime = inode->i_atime;
tmp.st_mtime = inode->i_mtime;
tmp.st_ctime = inode->i_ctime;
return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
}
#endif
static int cp_new_stat(struct inode * inode, struct stat * statbuf)
{
struct stat tmp;
unsigned int blocks, indirect;
memset(&tmp, 0, sizeof(tmp));
tmp.st_dev = kdev_t_to_nr(inode->i_dev);
tmp.st_ino = inode->i_ino;
tmp.st_mode = inode->i_mode;
tmp.st_nlink = inode->i_nlink;
tmp.st_uid = inode->i_uid;
tmp.st_gid = inode->i_gid;
tmp.st_rdev = kdev_t_to_nr(inode->i_rdev);
tmp.st_size = inode->i_size;
tmp.st_atime = inode->i_atime;
tmp.st_mtime = inode->i_mtime;
tmp.st_ctime = inode->i_ctime;
/*
* st_blocks and st_blksize are approximated with a simple algorithm if
* they aren't supported directly by the filesystem. The minix and msdos
* filesystems don't keep track of blocks, so they would either have to
* be counted explicitly (by delving into the file itself), or by using
* this simple algorithm to get a reasonable (although not 100% accurate)
* value.
*/
/*
* Use minix fs values for the number of direct and indirect blocks. The
* count is now exact for the minix fs except that it counts zero blocks.
* Everything is in BLOCK_SIZE'd units until the assignment to
* tmp.st_blksize.
*/
#define D_B 7
#define I_B (BLOCK_SIZE / sizeof(unsigned short))
if (!inode->i_blksize) {
blocks = (tmp.st_size + BLOCK_SIZE - 1) / BLOCK_SIZE;
if (blocks > D_B) {
indirect = (blocks - D_B + I_B - 1) / I_B;
blocks += indirect;
if (indirect > 1) {
indirect = (indirect - 1 + I_B - 1) / I_B;
blocks += indirect;
if (indirect > 1)
blocks++;
}
}
tmp.st_blocks = (BLOCK_SIZE / 512) * blocks;
tmp.st_blksize = BLOCK_SIZE;
} else {
tmp.st_blocks = inode->i_blocks;
tmp.st_blksize = inode->i_blksize;
}
return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
}
#if !defined(__alpha__) && !defined(__sparc__)
/*
* For backward compatibility? Maybe this should be moved
* into arch/i386 instead?
*/
asmlinkage int sys_stat(char * filename, struct __old_kernel_stat * statbuf)
{
struct dentry * dentry;
int error;
lock_kernel();
dentry = namei(filename);
error = PTR_ERR(dentry);
if (!IS_ERR(dentry)) {
struct inode * inode = dentry->d_inode;
error = do_revalidate(inode);
if (!error)
error = cp_old_stat(inode, statbuf);
dput(dentry);
}
unlock_kernel();
return error;
}
#endif
asmlinkage int sys_newstat(char * filename, struct stat * statbuf)
{
struct dentry * dentry;
int error;
lock_kernel();
dentry = namei(filename);
error = PTR_ERR(dentry);
if (!IS_ERR(dentry)) {
struct inode * inode = dentry->d_inode;
error = do_revalidate(inode);
if (!error)
error = cp_new_stat(inode,statbuf);
dput(dentry);
}
unlock_kernel();
return error;
}
#if !defined(__alpha__) && !defined(__sparc__)
/*
* For backward compatibility? Maybe this should be moved
* into arch/i386 instead?
*/
asmlinkage int sys_lstat(char * filename, struct __old_kernel_stat * statbuf)
{
struct dentry * dentry;
int error;
lock_kernel();
dentry = lnamei(filename);
error = PTR_ERR(dentry);
if (!IS_ERR(dentry)) {
struct inode * inode = dentry->d_inode;
error = do_revalidate(inode);
if (!error)
error = cp_old_stat(inode, statbuf);
dput(dentry);
}
unlock_kernel();
return error;
}
#endif
asmlinkage int sys_newlstat(char * filename, struct stat * statbuf)
{
struct dentry * dentry;
int error;
lock_kernel();
dentry = lnamei(filename);
error = PTR_ERR(dentry);
if (!IS_ERR(dentry)) {
struct inode * inode = dentry->d_inode;
error = do_revalidate(inode);
if (!error)
error = cp_new_stat(inode,statbuf);
dput(dentry);
}
unlock_kernel();
return error;
}
#if !defined(__alpha__) && !defined(__sparc__)
/*
* For backward compatibility? Maybe this should be moved
* into arch/i386 instead?
*/
asmlinkage int sys_fstat(unsigned int fd, struct __old_kernel_stat * statbuf)
{
struct file * f;
int err = -EBADF;
lock_kernel();
if (fd < NR_OPEN && (f = current->files->fd[fd]) != NULL) {
struct dentry * dentry = f->f_dentry;
struct inode * inode = dentry->d_inode;
err = do_revalidate(inode);
if (!err)
err = cp_old_stat(inode,statbuf);
}
unlock_kernel();
return err;
}
#endif
asmlinkage int sys_newfstat(unsigned int fd, struct stat * statbuf)
{
struct file * f;
int err = -EBADF;
lock_kernel();
if (fd < NR_OPEN && (f = current->files->fd[fd]) != NULL) {
struct dentry * dentry = f->f_dentry;
struct inode * inode = dentry->d_inode;
err = do_revalidate(inode);
if (!err)
err = cp_new_stat(inode,statbuf);
}
unlock_kernel();
return err;
}
asmlinkage int sys_readlink(const char * path, char * buf, int bufsiz)
{
struct dentry * dentry;
int error;
if (bufsiz <= 0)
return -EINVAL;
lock_kernel();
dentry = lnamei(path);
error = PTR_ERR(dentry);
if (!IS_ERR(dentry)) {
struct inode * inode = dentry->d_inode;
error = -EINVAL;
if (inode->i_op && inode->i_op->readlink && !(error = do_revalidate(inode))) {
UPDATE_ATIME(inode);
error = inode->i_op->readlink(inode,buf,bufsiz);
}
dput(dentry);
}
unlock_kernel();
return error;
}
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