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/*
* linux/fs/attr.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
* changes by Thomas Schoebel-Theuer
*/
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/smp_lock.h>
#include <linux/dnotify.h>
#include <linux/fcntl.h>
/* Taken over from the old code... */
/* POSIX UID/GID verification for setting inode attributes. */
int inode_change_ok(struct inode *inode, struct iattr *attr)
{
int retval = -EPERM;
unsigned int ia_valid = attr->ia_valid;
/* If force is set do it anyway. */
if (ia_valid & ATTR_FORCE)
goto fine;
/* Make sure a caller can chown. */
if ((ia_valid & ATTR_UID) &&
(current->fsuid != inode->i_uid ||
attr->ia_uid != inode->i_uid) && !capable(CAP_CHOWN))
goto error;
/* Make sure caller can chgrp. */
if ((ia_valid & ATTR_GID) &&
(!in_group_p(attr->ia_gid) && attr->ia_gid != inode->i_gid) &&
!capable(CAP_CHOWN))
goto error;
/* Make sure a caller can chmod. */
if (ia_valid & ATTR_MODE) {
if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
goto error;
/* Also check the setgid bit! */
if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid :
inode->i_gid) && !capable(CAP_FSETID))
attr->ia_mode &= ~S_ISGID;
}
/* Check for setting the inode time. */
if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET)) {
if (current->fsuid != inode->i_uid && !capable(CAP_FOWNER))
goto error;
}
fine:
retval = 0;
error:
return retval;
}
void inode_setattr(struct inode * inode, struct iattr * attr)
{
unsigned int ia_valid = attr->ia_valid;
if (ia_valid & ATTR_UID)
inode->i_uid = attr->ia_uid;
if (ia_valid & ATTR_GID)
inode->i_gid = attr->ia_gid;
if (ia_valid & ATTR_SIZE)
vmtruncate(inode, attr->ia_size);
if (ia_valid & ATTR_ATIME)
inode->i_atime = attr->ia_atime;
if (ia_valid & ATTR_MTIME)
inode->i_mtime = attr->ia_mtime;
if (ia_valid & ATTR_CTIME)
inode->i_ctime = attr->ia_ctime;
if (ia_valid & ATTR_MODE) {
inode->i_mode = attr->ia_mode;
if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
inode->i_mode &= ~S_ISGID;
}
mark_inode_dirty(inode);
}
static int setattr_mask(unsigned int ia_valid)
{
unsigned long dn_mask = 0;
if (ia_valid & ATTR_UID)
dn_mask |= DN_ATTRIB;
if (ia_valid & ATTR_GID)
dn_mask |= DN_ATTRIB;
if (ia_valid & ATTR_SIZE)
dn_mask |= DN_MODIFY;
/* both times implies a utime(s) call */
if ((ia_valid & (ATTR_ATIME|ATTR_MTIME)) == (ATTR_ATIME|ATTR_MTIME))
dn_mask |= DN_ATTRIB;
else if (ia_valid & ATTR_ATIME)
dn_mask |= DN_ACCESS;
else if (ia_valid & ATTR_MTIME)
dn_mask |= DN_MODIFY;
if (ia_valid & ATTR_MODE)
dn_mask |= DN_ATTRIB;
return dn_mask;
}
int notify_change(struct dentry * dentry, struct iattr * attr)
{
struct inode *inode = dentry->d_inode;
int error;
time_t now = CURRENT_TIME;
unsigned int ia_valid = attr->ia_valid;
if (!inode)
BUG();
attr->ia_ctime = now;
if (!(ia_valid & ATTR_ATIME_SET))
attr->ia_atime = now;
if (!(ia_valid & ATTR_MTIME_SET))
attr->ia_mtime = now;
lock_kernel();
if (inode->i_op && inode->i_op->setattr)
error = inode->i_op->setattr(dentry, attr);
else {
error = inode_change_ok(inode, attr);
if (!error)
inode_setattr(inode, attr);
}
unlock_kernel();
if (!error) {
unsigned long dn_mask = setattr_mask(ia_valid);
if (dn_mask)
inode_dir_notify(dentry->d_parent->d_inode, dn_mask);
}
return error;
}
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