LXR linux/fs/generic

   1/*
   2 * fs/generic_acl.c
   3 *
   4 * (C) 2005 Andreas Gruenbacher <agruen@suse.de>
   5 *
   6 * This file is released under the GPL.
   7 */
   8
   9#include <linux/sched.h>
  10#include <linux/fs.h>
  11#include <linux/generic_acl.h>
  12
  13/**
  14 * generic_acl_list  -  Generic xattr_handler->list() operation
  15 * @ops:        Filesystem specific getacl and setacl callbacks
  16 */
  17size_t
  18generic_acl_list(struct inode *inode, struct generic_acl_operations *ops,
  19                 int type, char *list, size_t list_size)
  20{
  21        struct posix_acl *acl;
  22        const char *name;
  23        size_t size;
  24
  25        acl = ops->getacl(inode, type);
  26        if (!acl)
  27                return 0;
  28        posix_acl_release(acl);
  29
  30        switch(type) {
  31                case ACL_TYPE_ACCESS:
  32                        name = POSIX_ACL_XATTR_ACCESS;
  33                        break;
  34
  35                case ACL_TYPE_DEFAULT:
  36                        name = POSIX_ACL_XATTR_DEFAULT;
  37                        break;
  38
  39                default:
  40                        return 0;
  41        }
  42        size = strlen(name) + 1;
  43        if (list && size <= list_size)
  44                memcpy(list, name, size);
  45        return size;
  46}
  47
  48/**
  49 * generic_acl_get  -  Generic xattr_handler->get() operation
  50 * @ops:        Filesystem specific getacl and setacl callbacks
  51 */
  52int
  53generic_acl_get(struct inode *inode, struct generic_acl_operations *ops,
  54                int type, void *buffer, size_t size)
  55{
  56        struct posix_acl *acl;
  57        int error;
  58
  59        acl = ops->getacl(inode, type);
  60        if (!acl)
  61                return -ENODATA;
  62        error = posix_acl_to_xattr(acl, buffer, size);
  63        posix_acl_release(acl);
  64
  65        return error;
  66}
  67
  68/**
  69 * generic_acl_set  -  Generic xattr_handler->set() operation
  70 * @ops:        Filesystem specific getacl and setacl callbacks
  71 */
  72int
  73generic_acl_set(struct inode *inode, struct generic_acl_operations *ops,
  74                int type, const void *value, size_t size)
  75{
  76        struct posix_acl *acl = NULL;
  77        int error;
  78
  79        if (S_ISLNK(inode->i_mode))
  80                return -EOPNOTSUPP;
  81        if (!is_owner_or_cap(inode))
  82                return -EPERM;
  83        if (value) {
  84                acl = posix_acl_from_xattr(value, size);
  85                if (IS_ERR(acl))
  86                        return PTR_ERR(acl);
  87        }
  88        if (acl) {
  89                mode_t mode;
  90
  91                error = posix_acl_valid(acl);
  92                if (error)
  93                        goto failed;
  94                switch(type) {
  95                        case ACL_TYPE_ACCESS:
  96                                mode = inode->i_mode;
  97                                error = posix_acl_equiv_mode(acl, &mode);
  98                                if (error < 0)
  99                                        goto failed;
 100                                inode->i_mode = mode;
 101                                if (error == 0) {
 102                                        posix_acl_release(acl);
 103                                        acl = NULL;
 104                                }
 105                                break;
 106
 107                        case ACL_TYPE_DEFAULT:
 108                                if (!S_ISDIR(inode->i_mode)) {
 109                                        error = -EINVAL;
 110                                        goto failed;
 111                                }
 112                                break;
 113                }
 114        }
 115        ops->setacl(inode, type, acl);
 116        error = 0;
 117failed:
 118        posix_acl_release(acl);
 119        return error;
 120}
 121
 122/**
 123 * generic_acl_init  -  Take care of acl inheritance at @inode create time
 124 * @ops:        Filesystem specific getacl and setacl callbacks
 125 *
 126 * Files created inside a directory with a default ACL inherit the
 127 * directory's default ACL.
 128 */
 129int
 130generic_acl_init(struct inode *inode, struct inode *dir,
 131                 struct generic_acl_operations *ops)
 132{
 133        struct posix_acl *acl = NULL;
 134        mode_t mode = inode->i_mode;
 135        int error;
 136
 137        inode->i_mode = mode & ~current_umask();
 138        if (!S_ISLNK(inode->i_mode))
 139                acl = ops->getacl(dir, ACL_TYPE_DEFAULT);
 140        if (acl) {
 141                struct posix_acl *clone;
 142
 143                if (S_ISDIR(inode->i_mode)) {
 144                        clone = posix_acl_clone(acl, GFP_KERNEL);
 145                        error = -ENOMEM;
 146                        if (!clone)
 147                                goto cleanup;
 148                        ops->setacl(inode, ACL_TYPE_DEFAULT, clone);
 149                        posix_acl_release(clone);
 150                }
 151                clone = posix_acl_clone(acl, GFP_KERNEL);
 152                error = -ENOMEM;
 153                if (!clone)
 154                        goto cleanup;
 155                error = posix_acl_create_masq(clone, &mode);
 156                if (error >= 0) {
 157                        inode->i_mode = mode;
 158                        if (error > 0)
 159                                ops->setacl(inode, ACL_TYPE_ACCESS, clone);
 160                }
 161                posix_acl_release(clone);
 162        }
 163        error = 0;
 164
 165cleanup:
 166        posix_acl_release(acl);
 167        return error;
 168}
 169
 170/**
 171 * generic_acl_chmod  -  change the access acl of @inode upon chmod()
 172 * @ops:        FIlesystem specific getacl and setacl callbacks
 173 *
 174 * A chmod also changes the permissions of the owner, group/mask, and
 175 * other ACL entries.
 176 */
 177int
 178generic_acl_chmod(struct inode *inode, struct generic_acl_operations *ops)
 179{
 180        struct posix_acl *acl, *clone;
 181        int error = 0;
 182
 183        if (S_ISLNK(inode->i_mode))
 184                return -EOPNOTSUPP;
 185        acl = ops->getacl(inode, ACL_TYPE_ACCESS);
 186        if (acl) {
 187                clone = posix_acl_clone(acl, GFP_KERNEL);
 188                posix_acl_release(acl);
 189                if (!clone)
 190                        return -ENOMEM;
 191                error = posix_acl_chmod_masq(clone, inode->i_mode);
 192                if (!error)
 193                        ops->setacl(inode, ACL_TYPE_ACCESS, clone);
 194                posix_acl_release(clone);
 195        }
 196        return error;
 197}
 198