Add some infrastructure for access control lists on in-memory
filesystems such as tmpfs and devpts. We can probably also use
this code from ext2 and ext3, but this hasn't been started, yet.

Signed-off-by: Andreas Gruenbacher <[EMAIL PROTECTED]>

Index: linux-2.6.11-rc2-mm2/fs/Kconfig
===================================================================
--- linux-2.6.11-rc2-mm2.orig/fs/Kconfig
+++ linux-2.6.11-rc2-mm2/fs/Kconfig
@@ -1809,6 +1809,10 @@ config AFS_FSCACHE
 config RXRPC
        tristate
 
+config GENERIC_ACL
+       bool
+       select FS_POSIX_ACL
+
 endmenu
 
 menu "Partition Types"
Index: linux-2.6.11-rc2-mm2/fs/Makefile
===================================================================
--- linux-2.6.11-rc2-mm2.orig/fs/Makefile
+++ linux-2.6.11-rc2-mm2/fs/Makefile
@@ -31,6 +31,7 @@ obj-$(CONFIG_BINFMT_FLAT)     += binfmt_flat
 
 obj-$(CONFIG_FS_MBCACHE)       += mbcache.o
 obj-$(CONFIG_FS_POSIX_ACL)     += posix_acl.o xattr_acl.o
+obj-$(CONFIG_GENERIC_ACL)      += generic_acl.o
 obj-$(CONFIG_NFS_ACL_SUPPORT)  += nfsacl.o
 
 obj-$(CONFIG_QUOTA)            += dquot.o
Index: linux-2.6.11-rc2-mm2/include/linux/generic_acl.h
===================================================================
--- /dev/null
+++ linux-2.6.11-rc2-mm2/include/linux/generic_acl.h
@@ -0,0 +1,30 @@
+/*
+ * fs/generic_acl.c
+ *
+ * (C) 2005 Andreas Gruenbacher <[EMAIL PROTECTED]>
+ *
+ * This file is released under the GPL.
+ */
+
+#ifndef GENERIC_ACL_H
+#define GENERIC_ACL_H
+
+#include <linux/posix_acl.h>
+#include <linux/xattr_acl.h>
+
+struct generic_acl_operations {
+       struct posix_acl *(*getacl)(struct inode *, int);
+       void (*setacl)(struct inode *, int, struct posix_acl *);
+};
+
+size_t generic_acl_list(struct inode *, struct generic_acl_operations *, int,
+                       char *, size_t);
+int generic_acl_get(struct inode *, struct generic_acl_operations *, int,
+                   void *, size_t);
+int generic_acl_set(struct inode *, struct generic_acl_operations *, int,
+                   const void *, size_t);
+int generic_acl_init(struct inode *, struct inode *,
+                    struct generic_acl_operations *);
+int generic_acl_chmod(struct inode *, struct generic_acl_operations *);
+
+#endif
Index: linux-2.6.11-rc2-mm2/fs/generic_acl.c
===================================================================
--- /dev/null
+++ linux-2.6.11-rc2-mm2/fs/generic_acl.c
@@ -0,0 +1,172 @@
+/*
+ * fs/generic_acl.c
+ *
+ * (C) 2005 Andreas Gruenbacher <[EMAIL PROTECTED]>
+ *
+ * This file is released under the GPL.
+ */
+
+#include <linux/sched.h>
+#include <linux/fs.h>
+#include <linux/generic_acl.h>
+
+size_t
+generic_acl_list(struct inode *inode, struct generic_acl_operations *ops,
+                int type, char *list, size_t list_size)
+{
+       struct posix_acl *acl;
+       const char *name;
+       size_t size;
+       
+       acl = ops->getacl(inode, type);
+       if (!acl)
+               return 0;
+       posix_acl_release(acl);
+
+       switch(type) {
+               case ACL_TYPE_ACCESS:
+                       name = XATTR_NAME_ACL_ACCESS;
+                       break;
+
+               case ACL_TYPE_DEFAULT:
+                       name = XATTR_NAME_ACL_DEFAULT;
+                       break;
+                       
+               default:
+                       return 0;
+       }
+       size = strlen(name) + 1;
+       if (list && size <= list_size)
+               memcpy(list, name, size);
+       return size;
+}
+
+int
+generic_acl_get(struct inode *inode, struct generic_acl_operations *ops,
+               int type, void *buffer, size_t size)
+{
+       struct posix_acl *acl;
+       int error;
+
+       acl = ops->getacl(inode, type);
+       if (!acl)
+               return -ENODATA;
+       error = posix_acl_to_xattr(acl, buffer, size);
+       posix_acl_release(acl);
+
+       return error;
+}
+
+int
+generic_acl_set(struct inode *inode, struct generic_acl_operations *ops,
+               int type, const void *value, size_t size)
+{
+       struct posix_acl *acl = NULL;
+       int error;
+
+       if (S_ISLNK(inode->i_mode))
+               return -EOPNOTSUPP;
+       if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
+               return -EPERM;
+       if (value) {
+               acl = posix_acl_from_xattr(value, size);
+               if (IS_ERR(acl))
+                       return PTR_ERR(acl);
+       }
+       if (acl) {
+               mode_t mode;
+
+               error = posix_acl_valid(acl);
+               if (error)
+                       goto failed;
+               switch(type) {
+                       case ACL_TYPE_ACCESS:
+                               mode = inode->i_mode;
+                               error = posix_acl_equiv_mode(acl, &mode);
+                               if (error < 0)
+                                       goto failed;
+                               inode->i_mode = mode;
+                               if (error == 0) {
+                                       posix_acl_release(acl);
+                                       acl = NULL;
+                               }
+                               break;
+
+                       case ACL_TYPE_DEFAULT:
+                               if (!S_ISDIR(inode->i_mode)) {
+                                       error = -EINVAL;
+                                       goto failed;
+                               }
+                               break;
+               }
+       }
+       ops->setacl(inode, type, acl);
+       error = 0;
+failed:
+       posix_acl_release(acl);
+       return error;
+}
+
+int
+generic_acl_init(struct inode *inode, struct inode *dir,
+                struct generic_acl_operations *ops)
+{
+       struct posix_acl *acl = NULL;
+       mode_t mode = inode->i_mode;
+       int error;
+
+       inode->i_mode = mode & ~current->fs->umask;
+       if (!S_ISLNK(inode->i_mode))
+               acl = ops->getacl(dir, ACL_TYPE_DEFAULT);
+       if (acl) {
+               struct posix_acl *clone;
+               
+               if (S_ISDIR(inode->i_mode)) {
+                       clone = posix_acl_clone(acl, GFP_KERNEL);
+                       error = -ENOMEM;
+                       if (!clone)
+                               goto cleanup;
+                       ops->setacl(inode, ACL_TYPE_DEFAULT, clone);
+                       posix_acl_release(clone);
+               }
+               clone = posix_acl_clone(acl, GFP_KERNEL);
+               error = -ENOMEM;
+               if (!clone)
+                       goto cleanup;
+               error = posix_acl_create_masq(clone, &mode);
+               if (error >= 0) {
+                       inode->i_mode = mode;
+                       if (error > 0) {
+                               ops->setacl(inode, ACL_TYPE_ACCESS, clone);
+                       }
+               }
+               posix_acl_release(clone);
+       }
+       error = 0;
+
+cleanup:
+       posix_acl_release(acl);
+       return error;
+}
+
+int
+generic_acl_chmod(struct inode *inode, struct generic_acl_operations *ops)
+{
+       struct posix_acl *acl, *clone;
+       int error = 0;
+
+       if (S_ISLNK(inode->i_mode))
+               return -EOPNOTSUPP;
+       acl = ops->getacl(inode, ACL_TYPE_ACCESS);
+       if (acl) {
+               clone = posix_acl_clone(acl, GFP_KERNEL);
+               posix_acl_release(acl);
+               if (!clone)
+                       return -ENOMEM;
+               error = posix_acl_chmod_masq(clone, inode->i_mode);
+               if (!error)
+                       ops->setacl(inode, ACL_TYPE_ACCESS, clone);
+               posix_acl_release(clone);
+       }
+       return error;
+}

--
Andreas Gruenbacher <[EMAIL PROTECTED]>
SUSE Labs, SUSE LINUX PRODUCTS GMBH

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