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
  12/* Taken over from the old code... */
  13
  14/* POSIX UID/GID verification for setting inode attributes. */
  15int inode_change_ok(struct inode *inode, struct iattr *attr)
  16{
  17        int retval = -EPERM;
  18        unsigned int ia_valid = attr->ia_valid;
  19
  20        /* If force is set do it anyway. */
  21        if (ia_valid & ATTR_FORCE)
  22                goto fine;
  23
  24        /* Make sure a caller can chown. */
  25        if ((ia_valid & ATTR_UID) &&
  26            (current->fsuid != inode->i_uid ||
  27             attr->ia_uid != inode->i_uid) && !capable(CAP_CHOWN))
  28                goto error;
  29
  30        /* Make sure caller can chgrp. */
  31        if ((ia_valid & ATTR_GID) &&
  32            (!in_group_p(attr->ia_gid) && attr->ia_gid != inode->i_gid) &&
  33            !capable(CAP_CHOWN))
  34                goto error;
  35
  36        /* Make sure a caller can chmod. */
  37        if (ia_valid & ATTR_MODE) {
  38                if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
  39                        goto error;
  40                /* Also check the setgid bit! */
  41                if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid :
  42                                inode->i_gid) && !capable(CAP_FSETID))
  43                        attr->ia_mode &= ~S_ISGID;
  44        }
  45
  46        /* Check for setting the inode time. */
  47        if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET)) {
  48                if (current->fsuid != inode->i_uid && !capable(CAP_FOWNER))
  49                        goto error;
  50        }
  51fine:
  52        retval = 0;
  53error:
  54        return retval;
  55}
  56
  57void inode_setattr(struct inode * inode, struct iattr * attr)
  58{
  59        unsigned int ia_valid = attr->ia_valid;
  60
  61        if (ia_valid & ATTR_UID)
  62                inode->i_uid = attr->ia_uid;
  63        if (ia_valid & ATTR_GID)
  64                inode->i_gid = attr->ia_gid;
  65        if (ia_valid & ATTR_SIZE)
  66                inode->i_size = attr->ia_size;
  67        if (ia_valid & ATTR_ATIME)
  68                inode->i_atime = attr->ia_atime;
  69        if (ia_valid & ATTR_MTIME)
  70                inode->i_mtime = attr->ia_mtime;
  71        if (ia_valid & ATTR_CTIME)
  72                inode->i_ctime = attr->ia_ctime;
  73        if (ia_valid & ATTR_MODE) {
  74                inode->i_mode = attr->ia_mode;
  75                if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
  76                        inode->i_mode &= ~S_ISGID;
  77        }
  78        mark_inode_dirty(inode);
  79}
  80
  81int notify_change(struct dentry * dentry, struct iattr * attr)
  82{
  83        struct inode *inode = dentry->d_inode;
  84        int error;
  85        time_t now = CURRENT_TIME;
  86        unsigned int ia_valid = attr->ia_valid;
  87
  88        attr->ia_ctime = now;
  89        if (!(ia_valid & ATTR_ATIME_SET))
  90                attr->ia_atime = now;
  91        if (!(ia_valid & ATTR_MTIME_SET))
  92                attr->ia_mtime = now;
  93
  94        if (inode->i_sb && inode->i_sb->s_op &&
  95            inode->i_sb->s_op->notify_change) 
  96                error = inode->i_sb->s_op->notify_change(dentry, attr);
  97        else {
  98                error = inode_change_ok(inode, attr);
  99                if (!error)
 100                        inode_setattr(inode, attr);
 101        }
 102        return error;
 103}
 104