/*
       *  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. */
  18  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. */
  24  	if (ia_valid & ATTR_FORCE)
  25  		goto fine;
      
      	/* Make sure a caller can chown. */
      	if ((ia_valid & ATTR_UID) &&
      	    (current->fsuid != inode->i_uid ||
  30  	     attr->ia_uid != inode->i_uid) && !capable(CAP_CHOWN))
  31  		goto error;
      
      	/* Make sure caller can chgrp. */
      	if ((ia_valid & ATTR_GID) &&
      	    (!in_group_p(attr->ia_gid) && attr->ia_gid != inode->i_gid) &&
  36  	    !capable(CAP_CHOWN))
  37  		goto error;
      
      	/* Make sure a caller can chmod. */
  40  	if (ia_valid & ATTR_MODE) {
  41  		if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
  42  			goto error;
      		/* Also check the setgid bit! */
      		if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid :
  45  				inode->i_gid) && !capable(CAP_FSETID))
      			attr->ia_mode &= ~S_ISGID;
      	}
      
      	/* Check for setting the inode time. */
  50  	if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET)) {
  51  		if (current->fsuid != inode->i_uid && !capable(CAP_FOWNER))
  52  			goto error;
      	}
      fine:
      	retval = 0;
      error:
  57  	return retval;
      }
      
  60  void inode_setattr(struct inode * inode, struct iattr * attr)
      {
      	unsigned int ia_valid = attr->ia_valid;
      
  64  	if (ia_valid & ATTR_UID)
      		inode->i_uid = attr->ia_uid;
  66  	if (ia_valid & ATTR_GID)
      		inode->i_gid = attr->ia_gid;
  68  	if (ia_valid & ATTR_SIZE)
      		vmtruncate(inode, attr->ia_size);
  70  	if (ia_valid & ATTR_ATIME)
      		inode->i_atime = attr->ia_atime;
  72  	if (ia_valid & ATTR_MTIME)
      		inode->i_mtime = attr->ia_mtime;
  74  	if (ia_valid & ATTR_CTIME)
      		inode->i_ctime = attr->ia_ctime;
  76  	if (ia_valid & ATTR_MODE) {
      		inode->i_mode = attr->ia_mode;
  78  		if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
      			inode->i_mode &= ~S_ISGID;
      	}
      	mark_inode_dirty(inode);
      }
      
  84  static int setattr_mask(unsigned int ia_valid)
      {
      	unsigned long dn_mask = 0;
      
  88  	if (ia_valid & ATTR_UID)
      		dn_mask |= DN_ATTRIB;
  90  	if (ia_valid & ATTR_GID)
      		dn_mask |= DN_ATTRIB;
  92  	if (ia_valid & ATTR_SIZE)
      		dn_mask |= DN_MODIFY;
      	/* both times implies a utime(s) call */
  95  	if ((ia_valid & (ATTR_ATIME|ATTR_MTIME)) == (ATTR_ATIME|ATTR_MTIME))
      		dn_mask |= DN_ATTRIB;
  97  	else if (ia_valid & ATTR_ATIME)
      		dn_mask |= DN_ACCESS;
  99  	else if (ia_valid & ATTR_MTIME)
      		dn_mask |= DN_MODIFY;
 101  	if (ia_valid & ATTR_MODE)
      		dn_mask |= DN_ATTRIB;
 103  	return dn_mask;
      }
      
 106  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;
      
 113  	if (!inode)
 114  		BUG();
      
      	attr->ia_ctime = now;
 117  	if (!(ia_valid & ATTR_ATIME_SET))
      		attr->ia_atime = now;
 119  	if (!(ia_valid & ATTR_MTIME_SET))
      		attr->ia_mtime = now;
      
 122  	lock_kernel();
 123  	if (inode->i_op && inode->i_op->setattr) 
      		error = inode->i_op->setattr(dentry, attr);
 125  	else {
      		error = inode_change_ok(inode, attr);
 127  		if (!error)
      			inode_setattr(inode, attr);
      	}
 130  	unlock_kernel();
 131  	if (!error) {
      		unsigned long dn_mask = setattr_mask(ia_valid);
 133  		if (dn_mask)
      			inode_dir_notify(dentry->d_parent->d_inode, dn_mask);
      	}
 136  	return error;
      }