posix-acl: implementation of POSIX ACL as a translator

Signed-off-by: Anand Avati <avati@gluster.com>

BUG: 2815 (Server-enforced ACLs)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=2815

1 files changed, 190 insertions, 0 deletions

diff --git a/xlators/system/posix-acl/src/posix-acl-xattr.c b/xlators/system/posix-acl/src/posix-acl-xattr.c
new file mode 100644
index 000000000..a473c3666
--- /dev/null
+++ b/xlators/system/posix-acl/src/posix-acl-xattr.c
@@ -0,0 +1,190 @@
+/*
+  Copyright (c) 2011 Gluster, Inc. <http://www.gluster.com>
+  This file is part of GlusterFS.
+
+  GlusterFS is free software; you can redistribute it and/or modify
+  it under the terms of the GNU Affero General Public License as published
+  by the Free Software Foundation; either version 3 of the License,
+  or (at your option) any later version.
+
+  GlusterFS is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  Affero General Public License for more details.
+
+  You should have received a copy of the GNU Affero General Public License
+  along with this program.  If not, see
+  <http://www.gnu.org/licenses/>.
+*/
+
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "posix-acl.h"
+#include "posix-acl-xattr.h"
+
+
+int
+posix_ace_cmp (const void *val1, const void *val2)
+{
+        const struct posix_ace *ace1 = NULL;
+        const struct posix_ace *ace2 = NULL;
+        int                     ret = 0;
+
+        ace1 = val1;
+        ace2 = val2;
+
+        ret = (ace1->tag - ace2->tag);
+        if (!ret)
+                ret = (ace1->id - ace2->id);
+
+        return ret;
+}
+
+
+void
+posix_acl_normalize (xlator_t *this, struct posix_acl *acl)
+{
+        qsort (acl->entries, acl->count, sizeof (struct posix_ace *),
+               posix_ace_cmp);
+}
+
+
+struct posix_acl *
+posix_acl_from_xattr (xlator_t *this, const char *xattr_buf, int xattr_size)
+{
+        struct posix_acl_xattr_header   *header = NULL;
+        struct posix_acl_xattr_entry    *entry = NULL;
+        struct posix_acl                *acl = NULL;
+        struct posix_ace                *ace = NULL;
+        int                              size = 0;
+        int                              count = 0;
+        int                              i = 0;
+
+        size = xattr_size;
+
+        if (size < sizeof (*header))
+                return NULL;
+
+        size -= sizeof (*header);
+
+        if (size % sizeof (*entry))
+                return NULL;
+
+        count = size / sizeof (*entry);
+
+        header = (struct posix_acl_xattr_header *) (xattr_buf);
+        entry = (struct posix_acl_xattr_entry *) (header + 1);
+
+        if (header->version != htole32 (POSIX_ACL_VERSION))
+                return NULL;
+
+        acl = posix_acl_new (this, count);
+        if (!acl)
+                return NULL;
+
+        ace = acl->entries;
+
+        for (i = 0; i < count; i++) {
+                ace->tag  = letoh16 (entry->tag);
+                ace->perm = letoh16 (entry->perm);
+
+                switch (ace->tag) {
+                case POSIX_ACL_USER_OBJ:
+                case POSIX_ACL_GROUP_OBJ:
+                case POSIX_ACL_MASK:
+                case POSIX_ACL_OTHER:
+                        ace->id = POSIX_ACL_UNDEFINED_ID;
+                        break;
+
+                case POSIX_ACL_GROUP:
+                case POSIX_ACL_USER:
+                        ace->id = letoh32 (entry->id);
+                        break;
+
+                default:
+                        goto err;
+                }
+
+                ace++;
+                entry++;
+        }
+
+        posix_acl_normalize (this, acl);
+
+        return acl;
+err:
+        posix_acl_destroy (this, acl);
+        return NULL;
+}
+
+
+int
+posix_acl_to_xattr (xlator_t *this, struct posix_acl *acl, char *xattr_buf,
+                    int xattr_size)
+{
+        int                             size = 0;
+        struct posix_acl_xattr_header  *header = NULL;
+        struct posix_acl_xattr_entry   *entry = NULL;
+        struct posix_ace               *ace = NULL;
+        int                             i = 0;
+
+        size = sizeof (*header) + (acl->count * sizeof (*entry));
+
+        if (xattr_size < size)
+                return size;
+
+        header = (struct posix_acl_xattr_header *) (xattr_buf);
+        entry = (struct posix_acl_xattr_entry *) (header + 1);
+        ace = acl->entries;
+
+        header->version = htole32 (POSIX_ACL_VERSION);
+
+        for (i = 0; i < acl->count; i++) {
+                entry->tag   = htole16 (ace->tag);
+                entry->perm  = htole16 (ace->perm);
+
+                switch (ace->tag) {
+                case POSIX_ACL_USER:
+                case POSIX_ACL_GROUP:
+                        entry->id  = htole32 (ace->id);
+                        break;
+                default:
+                        entry->id = POSIX_ACL_UNDEFINED_ID;
+                        break;
+                }
+
+                ace++;
+                entry++;
+        }
+
+        return 0;
+}
+
+
+int
+posix_acl_matches_xattr (xlator_t *this, struct posix_acl *acl, const char *buf,
+                         int size)
+{
+        struct posix_acl  *acl2 = NULL;
+        int                ret = 1;
+
+        acl2 = posix_acl_from_xattr (this, buf, size);
+        if (!acl2)
+                return 0;
+
+        if (acl->count != acl2->count) {
+                ret = 0;
+                goto out;
+        }
+
+        if (memcmp (acl->entries, acl2->entries,
+                    (acl->count * sizeof (struct posix_ace))))
+                ret = 0;
+out:
+        posix_acl_destroy (this, acl2);
+
+        return ret;
+}
+