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            (!in_group_p(attr->ia_gid) && attr->ia_gid != inode->i_gid) &&
  37            !capable(CAP_CHOWN))
  38                goto error;
  39
  40        /* Make sure a caller can chmod. */
  41        if (ia_valid & ATTR_MODE) {
  42                if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
  43                        goto error;
  44                /* Also check the setgid bit! */
  45                if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid :
  46                                inode->i_gid) && !capable(CAP_FSETID))
  47                        attr->ia_mode &= ~S_ISGID;
  48        }
  49
  50        /* Check for setting the inode time. */
  51        if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET)) {
  52                if (current->fsuid != inode->i_uid && !capable(CAP_FOWNER))
  53                        goto error;
  54        }
  55fine:
  56        retval = 0;
  57error:
  58        return retval;
  59}
  60
  61int inode_setattr(struct inode * inode, struct iattr * attr)
  62{
  63        unsigned int ia_valid = attr->ia_valid;
  64        int error = 0;
  65
  66        if (ia_valid & ATTR_SIZE) {
  67                error = vmtruncate(inode, attr->ia_size);
  68                if (error)
  69                        goto out;
  70        }
  71
  72        if (ia_valid & ATTR_UID)
  73                inode->i_uid = attr->ia_uid;
  74        if (ia_valid & ATTR_GID)
  75                inode->i_gid = attr->ia_gid;
  76        if (ia_valid & ATTR_ATIME)
  77                inode->i_atime = attr->ia_atime;
  78        if (ia_valid & ATTR_MTIME)
  79                inode->i_mtime = attr->ia_mtime;
  80        if (ia_valid & ATTR_CTIME)
  81                inode->i_ctime = attr->ia_ctime;
  82        if (ia_valid & ATTR_MODE) {
  83                inode->i_mode = attr->ia_mode;
  84                if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
  85                        inode->i_mode &= ~S_ISGID;
  86        }
  87        mark_inode_dirty(inode);
  88out:
  89        return error;
  90}
  91
  92static int setattr_mask(unsigned int ia_valid)
  93{
  94        unsigned long dn_mask = 0;
  95
  96        if (ia_valid & ATTR_UID)
  97                dn_mask |= DN_ATTRIB;
  98        if (ia_valid & ATTR_GID)
  99                dn_mask |= DN_ATTRIB;
 100        if (ia_valid & ATTR_SIZE)
 101                dn_mask |= DN_MODIFY;
 102        /* both times implies a utime(s) call */
 103        if ((ia_valid & (ATTR_ATIME|ATTR_MTIME)) == (ATTR_ATIME|ATTR_MTIME))
 104                dn_mask |= DN_ATTRIB;
 105        else if (ia_valid & ATTR_ATIME)
 106                dn_mask |= DN_ACCESS;
 107        else if (ia_valid & ATTR_MTIME)
 108                dn_mask |= DN_MODIFY;
 109        if (ia_valid & ATTR_MODE)
 110                dn_mask |= DN_ATTRIB;
 111        return dn_mask;
 112}
 113
 114int notify_change(struct dentry * dentry, struct iattr * attr)
 115{
 116        struct inode *inode = dentry->d_inode;
 117        int error;
 118        time_t now = CURRENT_TIME;
 119        unsigned int ia_valid = attr->ia_valid;
 120
 121        if (!inode)
 122                BUG();
 123
 124        attr->ia_ctime = now;
 125        if (!(ia_valid & ATTR_ATIME_SET))
 126                attr->ia_atime = now;
 127        if (!(ia_valid & ATTR_MTIME_SET))
 128                attr->ia_mtime = now;
 129
 130        lock_kernel();
 131        if (inode->i_op && inode->i_op->setattr) 
 132                error = inode->i_op->setattr(dentry, attr);
 133        else {
 134                error = inode_change_ok(inode, attr);
 135                if (!error) {
 136                        if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||
 137                            (ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid))
 138                                error = DQUOT_TRANSFER(inode, attr) ? -EDQUOT : 0;
 139                        if (!error)
 140                                error = inode_setattr(inode, attr);
 141                }
 142        }
 143        unlock_kernel();
 144        if (!error) {
 145                unsigned long dn_mask = setattr_mask(ia_valid);
 146                if (dn_mask)
 147                        dnotify_parent(dentry, dn_mask);
 148        }
 149        return error;
 150}
 151