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1275 |
phoenix |
/*
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* linux/fs/attr.c
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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* changes by Thomas Schoebel-Theuer
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*/
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <linux/string.h>
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#include <linux/smp_lock.h>
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#include <linux/dnotify.h>
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#include <linux/fcntl.h>
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#include <linux/quotaops.h>
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/* Taken over from the old code... */
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/* POSIX UID/GID verification for setting inode attributes. */
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int inode_change_ok(struct inode *inode, struct iattr *attr)
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{
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int retval = -EPERM;
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unsigned int ia_valid = attr->ia_valid;
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/* If force is set do it anyway. */
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if (ia_valid & ATTR_FORCE)
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goto fine;
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/* Make sure a caller can chown. */
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if ((ia_valid & ATTR_UID) &&
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(current->fsuid != inode->i_uid ||
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attr->ia_uid != inode->i_uid) && !capable(CAP_CHOWN))
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goto error;
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/* Make sure caller can chgrp. */
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if ((ia_valid & ATTR_GID) &&
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(!in_group_p(attr->ia_gid) && attr->ia_gid != inode->i_gid) &&
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!capable(CAP_CHOWN))
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goto error;
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/* Make sure a caller can chmod. */
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if (ia_valid & ATTR_MODE) {
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if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
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goto error;
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/* Also check the setgid bit! */
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if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid :
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inode->i_gid) && !capable(CAP_FSETID))
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attr->ia_mode &= ~S_ISGID;
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}
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/* Check for setting the inode time. */
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if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET)) {
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if (current->fsuid != inode->i_uid && !capable(CAP_FOWNER))
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goto error;
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}
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fine:
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retval = 0;
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error:
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return retval;
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}
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int inode_setattr(struct inode * inode, struct iattr * attr)
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{
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unsigned int ia_valid = attr->ia_valid;
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int error = 0;
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if (ia_valid & ATTR_SIZE) {
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error = vmtruncate(inode, attr->ia_size);
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if (error)
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goto out;
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}
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if (ia_valid & ATTR_UID)
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inode->i_uid = attr->ia_uid;
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if (ia_valid & ATTR_GID)
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inode->i_gid = attr->ia_gid;
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if (ia_valid & ATTR_ATIME)
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inode->i_atime = attr->ia_atime;
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if (ia_valid & ATTR_MTIME)
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inode->i_mtime = attr->ia_mtime;
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if (ia_valid & ATTR_CTIME)
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inode->i_ctime = attr->ia_ctime;
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if (ia_valid & ATTR_MODE) {
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inode->i_mode = attr->ia_mode;
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if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
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inode->i_mode &= ~S_ISGID;
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}
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mark_inode_dirty(inode);
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out:
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return error;
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}
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static int setattr_mask(unsigned int ia_valid)
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{
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unsigned long dn_mask = 0;
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if (ia_valid & ATTR_UID)
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dn_mask |= DN_ATTRIB;
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if (ia_valid & ATTR_GID)
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dn_mask |= DN_ATTRIB;
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if (ia_valid & ATTR_SIZE)
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dn_mask |= DN_MODIFY;
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/* both times implies a utime(s) call */
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if ((ia_valid & (ATTR_ATIME|ATTR_MTIME)) == (ATTR_ATIME|ATTR_MTIME))
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dn_mask |= DN_ATTRIB;
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else if (ia_valid & ATTR_ATIME)
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dn_mask |= DN_ACCESS;
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else if (ia_valid & ATTR_MTIME)
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dn_mask |= DN_MODIFY;
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if (ia_valid & ATTR_MODE)
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dn_mask |= DN_ATTRIB;
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return dn_mask;
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}
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int notify_change(struct dentry * dentry, struct iattr * attr)
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{
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struct inode *inode = dentry->d_inode;
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int error;
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time_t now = CURRENT_TIME;
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unsigned int ia_valid = attr->ia_valid;
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if (!inode)
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BUG();
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attr->ia_ctime = now;
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if (!(ia_valid & ATTR_ATIME_SET))
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attr->ia_atime = now;
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if (!(ia_valid & ATTR_MTIME_SET))
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attr->ia_mtime = now;
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lock_kernel();
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if (inode->i_op && inode->i_op->setattr)
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error = inode->i_op->setattr(dentry, attr);
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else {
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error = inode_change_ok(inode, attr);
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if (!error) {
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if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||
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(ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid))
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error = DQUOT_TRANSFER(inode, attr) ? -EDQUOT : 0;
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if (!error)
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error = inode_setattr(inode, attr);
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}
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}
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unlock_kernel();
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if (!error) {
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unsigned long dn_mask = setattr_mask(ia_valid);
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if (dn_mask)
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dnotify_parent(dentry, dn_mask);
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}
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return error;
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}
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