LXR linux-old/fs/attr.c

   1/*
   2 *  linux/fs/attr.c
   3 *
   4 *  Copyright (C) 1991, 1992  Linus Torvalds
   5 *  changes by Thomas Schoebel-Theuer
   6 */
   7
   8#include <linux/sched.h>
   9#include <linux/mm.h>
  10#include <linux/string.h>
  11#include <linux/smp_lock.h>
  12#include <linux/dnotify.h>
  13#include <linux/fcntl.h>
  14#include <linux/quotaops.h>
  15
  16/* Taken over from the old code... */
  17
  18/* POSIX UID/GID verification for setting inode attributes. */
  19int inode_change_ok(struct inode *inode, struct iattr *attr)
  20{
  21        int retval = -EPERM;
  22        unsigned int ia_valid = attr->ia_valid;
  23
  24        /* If force is set do it anyway. */
  25        if (ia_valid & ATTR_FORCE)
  26                goto fine;
  27
  28        /* Make sure a caller can chown. */
  29        if ((ia_valid & ATTR_UID) &&
  30            (current->fsuid != inode->i_uid ||
  31             attr->ia_uid != inode->i_uid) && !capable(CAP_CHOWN))
  32                goto error;
  33
  34        /* Make sure caller can chgrp. */
  35        if ((ia_valid & ATTR_GID) &&
  36            (current->fsuid != inode->i_uid ||
  37            (!in_group_p(attr->ia_gid) && attr->ia_gid != inode->i_gid)) &&
  38            !capable(CAP_CHOWN))
  39                goto error;
  40
  41        /* Make sure a caller can chmod. */
  42        if (ia_valid & ATTR_MODE) {
  43                if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
  44                        goto error;
  45                /* Also check the setgid bit! */
  46                if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid :
  47                                inode->i_gid) && !capable(CAP_FSETID))
  48                        attr->ia_mode &= ~S_ISGID;
  49        }
  50
  51        /* Check for setting the inode time. */
  52        if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET)) {
  53                if (current->fsuid != inode->i_uid && !capable(CAP_FOWNER))
  54                        goto error;
  55        }
  56fine:
  57        retval = 0;
  58error:
  59        return retval;
  60}
  61
  62int inode_setattr(struct inode * inode, struct iattr * attr)
  63{
  64        unsigned int ia_valid = attr->ia_valid;
  65        int error = 0;
  66
  67        if (ia_valid & ATTR_SIZE) {
  68                error = vmtruncate(inode, attr->ia_size);
  69                if (error)
  70                        goto out;
  71        }
  72
  73        if (ia_valid & ATTR_UID)
  74                inode->i_uid = attr->ia_uid;
  75        if (ia_valid & ATTR_GID)
  76                inode->i_gid = attr->ia_gid;
  77        if (ia_valid & ATTR_ATIME)
  78                inode->i_atime = attr->ia_atime;
  79        if (ia_valid & ATTR_MTIME)
  80                inode->i_mtime = attr->ia_mtime;
  81        if (ia_valid & ATTR_CTIME)
  82                inode->i_ctime = attr->ia_ctime;
  83        if (ia_valid & ATTR_MODE) {
  84                inode->i_mode = attr->ia_mode;
  85                if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
  86                        inode->i_mode &= ~S_ISGID;
  87        }
  88        mark_inode_dirty(inode);
  89out:
  90        return error;
  91}
  92
  93static int setattr_mask(unsigned int ia_valid)
  94{
  95        unsigned long dn_mask = 0;
  96
  97        if (ia_valid & ATTR_UID)
  98                dn_mask |= DN_ATTRIB;
  99        if (ia_valid & ATTR_GID)
 100                dn_mask |= DN_ATTRIB;
 101        if (ia_valid & ATTR_SIZE)
 102                dn_mask |= DN_MODIFY;
 103        /* both times implies a utime(s) call */
 104        if ((ia_valid & (ATTR_ATIME|ATTR_MTIME)) == (ATTR_ATIME|ATTR_MTIME))
 105                dn_mask |= DN_ATTRIB;
 106        else if (ia_valid & ATTR_ATIME)
 107                dn_mask |= DN_ACCESS;
 108        else if (ia_valid & ATTR_MTIME)
 109                dn_mask |= DN_MODIFY;
 110        if (ia_valid & ATTR_MODE)
 111                dn_mask |= DN_ATTRIB;
 112        return dn_mask;
 113}
 114
 115int notify_change(struct dentry * dentry, struct iattr * attr)
 116{
 117        struct inode *inode = dentry->d_inode;
 118        int error;
 119        time_t now = CURRENT_TIME;
 120        unsigned int ia_valid = attr->ia_valid;
 121
 122        if (!inode)
 123                BUG();
 124
 125        attr->ia_ctime = now;
 126        if (!(ia_valid & ATTR_ATIME_SET))
 127                attr->ia_atime = now;
 128        if (!(ia_valid & ATTR_MTIME_SET))
 129                attr->ia_mtime = now;
 130
 131        lock_kernel();
 132        if (inode->i_op && inode->i_op->setattr) 
 133                error = inode->i_op->setattr(dentry, attr);
 134        else {
 135                error = inode_change_ok(inode, attr);
 136                if (!error) {
 137                        if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||
 138                            (ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid))
 139                                error = DQUOT_TRANSFER(inode, attr) ? -EDQUOT : 0;
 140                        if (!error)
 141                                error = inode_setattr(inode, attr);
 142                }
 143        }
 144        unlock_kernel();
 145        if (!error) {
 146                unsigned long dn_mask = setattr_mask(ia_valid);
 147                if (dn_mask)
 148                        dnotify_parent(dentry, dn_mask);
 149        }
 150        return error;
 151}
 152