posix: add ACL translation for the GF_POSIX_ACL_*_KEY xattr

Adding support for two virtual extended attributes that are used for
converting a binary POSIX ACL to a POSIX.1e long ACL text format. This
makes it possible to transfer the ACL over the network to a different OS
which can convert the POSIX.1e text format to its native structures.

The following xattrs are sent over RPC in SETXATTR/GETXATTR procedures,
and contain the POSIX.1e long ACL text format:

- glusterfs.posix.acl: maps to ACL_TYPE_ACCESS
- glusterfs.posix.default_acl: maps to ACL_TYPE_DEFAULT

acl_from_text() (from libacl) converts the text format into an acl_t
structure. This structure is then used by acl_set_file() to set the ACL
in the filesystem.

libacl-devel is needed for linking against libacl, so it has been added
to the BuildRequires in the .spec.

NetBSD does not support POSIX ACLs. Trying to get/set POSIX ACLs on a
storage server running NetBSD, an error will be returned with errno set
to ENOTSUP. Faking support, but not enforcing ACLs seems wrong to me.

URL: http://www.gluster.org/community/documentation/index.php/Features/Improved_POSIX_ACLs
BUG: 1185654
Change-Id: Ic5eb73d69190d3492df2f711d0436775eeea7de3
Signed-off-by: Niels de Vos <ndevos@redhat.com>
Reviewed-on: http://review.gluster.org/9627
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: soumya k <skoduri@redhat.com>
Reviewed-by: Raghavendra Bhat <raghavendra@redhat.com>

4 files changed, 113 insertions, 1 deletions

diff --git a/xlators/storage/posix/src/Makefile.am b/xlators/storage/posix/src/Makefile.am
index 88efcc784db..509b0524921 100644
--- a/xlators/storage/posix/src/Makefile.am
+++ b/xlators/storage/posix/src/Makefile.am
@@ -5,7 +5,8 @@ xlatordir = $(libdir)/glusterfs/$(PACKAGE_VERSION)/xlator/storage
 posix_la_LDFLAGS = -module -avoid-version
 
 posix_la_SOURCES = posix.c posix-helpers.c posix-handle.c posix-aio.c
-posix_la_LIBADD = $(top_builddir)/libglusterfs/src/libglusterfs.la $(LIBAIO)
+posix_la_LIBADD = $(top_builddir)/libglusterfs/src/libglusterfs.la $(LIBAIO) \
+                  $(ACL_LIBS)
 
 noinst_HEADERS = posix.h posix-mem-types.h posix-handle.h posix-aio.h
 
diff --git a/xlators/storage/posix/src/posix-helpers.c b/xlators/storage/posix/src/posix-helpers.c
index ea469bf6109..edbf0241f26 100644
--- a/xlators/storage/posix/src/posix-helpers.c
+++ b/xlators/storage/posix/src/posix-helpers.c
@@ -24,6 +24,14 @@
 #include <sys/stat.h>
 #include <signal.h>
 
+#ifdef HAVE_SYS_ACL_H
+#ifdef HAVE_ACL_LIBACL_H /* for acl_to_any_text() */
+#include <acl/libacl.h>
+#else /* FreeBSD and others */
+#include <sys/acl.h>
+#endif
+#endif
+
 #ifndef GF_BSD_HOST_OS
 #include <alloca.h>
 #endif /* GF_BSD_HOST_OS */
@@ -887,6 +895,75 @@ out:
         return op_ret;
 }
 
+#ifdef HAVE_SYS_ACL_H
+int
+posix_pacl_set (const char *path, const char *key, const char *acl_s)
+{
+        int ret = -1;
+        acl_t acl = NULL;
+        acl_type_t type = 0;
+
+        type = gf_posix_acl_get_type (key);
+
+        acl = acl_from_text (acl_s);
+        ret = acl_set_file (path, type, acl);
+        acl_free (acl);
+
+        return ret;
+}
+
+int
+posix_pacl_get (const char *path, const char *key, char **acl_s)
+{
+        int ret = -1;
+        acl_t acl = NULL;
+        acl_type_t type = 0;
+        char *acl_tmp = NULL;
+
+        type = gf_posix_acl_get_type (key);
+        if (!type)
+                return -1;
+
+        acl = acl_get_file (path, type);
+        if (!acl)
+                return -1;
+
+#ifdef HAVE_ACL_LIBACL_H
+        acl_tmp = acl_to_any_text (acl, NULL, ',',
+                                   TEXT_ABBREVIATE | TEXT_NUMERIC_IDS);
+#else /* FreeBSD and the like */
+        acl_tmp = acl_to_text_np (acl, NULL, ACL_TEXT_NUMERIC_IDS);
+#endif
+        if (!acl_tmp)
+                goto free_acl;
+
+        *acl_s = gf_strdup (acl_tmp);
+        if (*acl_s)
+                ret = 0;
+
+        acl_free (acl_tmp);
+free_acl:
+        acl_free (acl);
+
+        return ret;
+}
+#else /* !HAVE_SYS_ACL_H (NetBSD) */
+int
+posix_pacl_set (const char *path, const char *key, const char *acl_s)
+{
+        errno = ENOTSUP;
+        return -1;
+}
+
+int
+posix_pacl_get (const char *path, const char *key, char **acl_s)
+{
+        errno = ENOTSUP;
+        return -1;
+}
+#endif
+
+
 #ifdef GF_DARWIN_HOST_OS
 static
 void posix_dump_buffer (xlator_t *this, const char *real_path, const char *key,
@@ -921,6 +998,8 @@ posix_handle_pair (xlator_t *this, const char *real_path,
         } else if (ZR_FILE_CONTENT_REQUEST(key)) {
                 ret = posix_set_file_contents (this, real_path, key, value,
                                                flags);
+        } else if (GF_POSIX_ACL_REQUEST (key)) {
+                ret = posix_pacl_set (real_path, key, value->data);
         } else {
                 sys_ret = sys_lsetxattr (real_path, key, value->data,
                                          value->len, flags);
diff --git a/xlators/storage/posix/src/posix.c b/xlators/storage/posix/src/posix.c
index ccd441a2d62..47afed7fdad 100644
--- a/xlators/storage/posix/src/posix.c
+++ b/xlators/storage/posix/src/posix.c
@@ -3660,6 +3660,32 @@ posix_getxattr (call_frame_t *frame, xlator_t *this,
                 goto out;
         }
 
+        if (loc->inode && name && GF_POSIX_ACL_REQUEST (name)) {
+                ret = posix_pacl_get (real_path, name, &value);
+                if (ret || !value) {
+                        gf_log (this->name, GF_LOG_WARNING,
+                                "could not get acl (%s) for %s: %s", name,
+                                real_path, strerror (errno));
+                        op_ret = -1;
+                        op_errno = errno;
+                        goto out;
+                }
+
+                ret = dict_set_dynstr (dict, (char *)name, value);
+                if (ret < 0) {
+                        GF_FREE (value);
+                        gf_log (this->name, GF_LOG_WARNING,
+                                "could not set acl (%s) for %s in dictionary: "
+                                "(%s)", name, real_path, strerror (errno));
+                        op_ret = -1;
+                        op_errno = errno;
+                        goto out;
+                }
+
+                size = ret;
+                goto done;
+        }
+
 	if (loc->inode && name &&
 	    (strncmp (name, GF_XATTR_GET_REAL_FILENAME_KEY,
 		      strlen (GF_XATTR_GET_REAL_FILENAME_KEY)) == 0)) {
diff --git a/xlators/storage/posix/src/posix.h b/xlators/storage/posix/src/posix.h
index 870315d0ea2..bdb56b1d59d 100644
--- a/xlators/storage/posix/src/posix.h
+++ b/xlators/storage/posix/src/posix.h
@@ -236,4 +236,10 @@ posix_get_ancestry (xlator_t *this, inode_t *leaf_inode,
 void
 posix_gfid_unset (xlator_t *this, dict_t *xdata);
 
+int
+posix_pacl_set (const char *path, const char *key, const char *acl_s);
+
+int
+posix_pacl_get (const char *path, const char *key, char **acl_s);
+
 #endif /* _POSIX_H */