virtio-9p: Support mapped posix acl

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>

Makefile.objs

@@ -250,7 +250,7 @@ adlib.o fmopl.o: QEMU_CFLAGS += -DBUILD_Y8950=0
 hw-obj-$(CONFIG_SOUND) += $(sound-obj-y)
 
 hw-obj-$(CONFIG_VIRTFS) += virtio-9p-debug.o virtio-9p-local.o virtio-9p-xattr.o
-hw-obj-$(CONFIG_VIRTFS) += virtio-9p-xattr-user.o
+hw-obj-$(CONFIG_VIRTFS) += virtio-9p-xattr-user.o virtio-9p-posix-acl.o
 
 ######################################################################
 # libdis

hw/virtio-9p-posix-acl.c

@@ -0,0 +1,140 @@
+/*
+ * Virtio 9p system.posix* xattr callback
+ *
+ * Copyright IBM, Corp. 2010
+ *
+ * Authors:
+ * Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ */
+
+#include <sys/types.h>
+#include <attr/xattr.h>
+#include "virtio.h"
+#include "virtio-9p.h"
+#include "file-op-9p.h"
+#include "virtio-9p-xattr.h"
+
+#define MAP_ACL_ACCESS "user.virtfs.system.posix_acl_access"
+#define MAP_ACL_DEFAULT "user.virtfs.system.posix_acl_default"
+#define ACL_ACCESS "system.posix_acl_access"
+#define ACL_DEFAULT "system.posix_acl_default"
+
+static ssize_t mp_pacl_getxattr(FsContext *ctx, const char *path,
+                                const char *name, void *value, size_t size)
+{
+    return lgetxattr(rpath(ctx, path), MAP_ACL_ACCESS, value, size);
+}
+
+static ssize_t mp_pacl_listxattr(FsContext *ctx, const char *path,
+                                 char *name, void *value, size_t osize)
+{
+    ssize_t len = sizeof(ACL_ACCESS);
+
+    if (!value) {
+        return len;
+    }
+
+    if (osize < len) {
+        errno = ERANGE;
+        return -1;
+    }
+
+    strncpy(value, ACL_ACCESS, len);
+    return 0;
+}
+
+static int mp_pacl_setxattr(FsContext *ctx, const char *path, const char *name,
+                            void *value, size_t size, int flags)
+{
+    return lsetxattr(rpath(ctx, path), MAP_ACL_ACCESS, value, size, flags);
+}
+
+static int mp_pacl_removexattr(FsContext *ctx,
+                               const char *path, const char *name)
+{
+    int ret;
+    ret  = lremovexattr(rpath(ctx, path), MAP_ACL_ACCESS);
+    if (ret == -1 && errno == ENODATA) {
+        /*
+         * We don't get ENODATA error when trying to remote a
+         * posix acl that is not present. So don't throw the error
+         * even in case of mapped security model
+         */
+        errno = 0;
+        ret = 0;
+    }
+    return ret;
+}
+
+static ssize_t mp_dacl_getxattr(FsContext *ctx, const char *path,
+                                const char *name, void *value, size_t size)
+{
+    return lgetxattr(rpath(ctx, path), MAP_ACL_DEFAULT, value, size);
+}
+
+static ssize_t mp_dacl_listxattr(FsContext *ctx, const char *path,
+                                 char *name, void *value, size_t osize)
+{
+    ssize_t len = sizeof(ACL_DEFAULT);
+
+    if (!value) {
+        return len;
+    }
+
+    if (osize < len) {
+        errno = ERANGE;
+        return -1;
+    }
+
+    strncpy(value, ACL_DEFAULT, len);
+    return 0;
+}
+
+static int mp_dacl_setxattr(FsContext *ctx, const char *path, const char *name,
+                            void *value, size_t size, int flags)
+{
+    return lsetxattr(rpath(ctx, path), MAP_ACL_DEFAULT, value, size, flags);
+}
+
+static int mp_dacl_removexattr(FsContext *ctx,
+                               const char *path, const char *name)
+{
+    return lremovexattr(rpath(ctx, path), MAP_ACL_DEFAULT);
+}
+
+
+XattrOperations mapped_pacl_xattr = {
+    .name = "system.posix_acl_access",
+    .getxattr = mp_pacl_getxattr,
+    .setxattr = mp_pacl_setxattr,
+    .listxattr = mp_pacl_listxattr,
+    .removexattr = mp_pacl_removexattr,
+};
+
+XattrOperations mapped_dacl_xattr = {
+    .name = "system.posix_acl_default",
+    .getxattr = mp_dacl_getxattr,
+    .setxattr = mp_dacl_setxattr,
+    .listxattr = mp_dacl_listxattr,
+    .removexattr = mp_dacl_removexattr,
+};
+
+XattrOperations passthrough_acl_xattr = {
+    .name = "system.posix_acl_",
+    .getxattr = pt_getxattr,
+    .setxattr = pt_setxattr,
+    .listxattr = pt_listxattr,
+    .removexattr = pt_removexattr,
+};
+
+XattrOperations none_acl_xattr = {
+    .name = "system.posix_acl_",
+    .getxattr = notsup_getxattr,
+    .setxattr = notsup_setxattr,
+    .listxattr = notsup_listxattr,
+    .removexattr = notsup_removexattr,
+};

hw/virtio-9p-xattr-user.c

@@ -37,11 +37,19 @@ static ssize_t mp_user_listxattr(FsContext *ctx, const char *path,
 {
     int name_size = strlen(name) + 1;
     if (strncmp(name, "user.virtfs.", 12) == 0) {
-        /*
-         * Don't allow fetch of user.virtfs namesapce
-         * in case of mapped security
-         */
-        return 0;
+
+        /*  check if it is a mapped posix acl */
+        if (strncmp(name, "user.virtfs.system.posix_acl_", 29) == 0) {
+            /* adjust the name and size */
+            name += 12;
+            name_size -= 12;
+        } else {
+            /*
+             * Don't allow fetch of user.virtfs namesapce
+             * in case of mapped security
+             */
+            return 0;
+        }
     }
     if (!value) {
         return name_size;

hw/virtio-9p-xattr.c

@@ -137,16 +137,20 @@ int v9fs_remove_xattr(FsContext *ctx,
 
 XattrOperations *mapped_xattr_ops[] = {
     &mapped_user_xattr,
+    &mapped_pacl_xattr,
+    &mapped_dacl_xattr,
     NULL,
 };
 
 XattrOperations *passthrough_xattr_ops[] = {
     &passthrough_user_xattr,
+    &passthrough_acl_xattr,
     NULL,
 };
 
 /* for .user none model should be same as passthrough */
 XattrOperations *none_xattr_ops[] = {
     &passthrough_user_xattr,
+    &none_acl_xattr,
     NULL,
 };

hw/virtio-9p-xattr.h

@@ -32,6 +32,11 @@ typedef struct xattr_operations
 extern XattrOperations mapped_user_xattr;
 extern XattrOperations passthrough_user_xattr;
 
+extern XattrOperations mapped_pacl_xattr;
+extern XattrOperations mapped_dacl_xattr;
+extern XattrOperations passthrough_acl_xattr;
+extern XattrOperations none_acl_xattr;
+
 extern XattrOperations *mapped_xattr_ops[];
 extern XattrOperations *passthrough_xattr_ops[];
 extern XattrOperations *none_xattr_ops[];
@@ -66,4 +71,33 @@ static inline int pt_removexattr(FsContext *ctx,
     return lremovexattr(rpath(ctx, path), name);
 }
 
+static inline ssize_t notsup_getxattr(FsContext *ctx, const char *path,
+                                      const char *name, void *value,
+                                      size_t size)
+{
+    errno = ENOTSUP;
+    return -1;
+}
+
+static inline int notsup_setxattr(FsContext *ctx, const char *path,
+                                  const char *name, void *value,
+                                  size_t size, int flags)
+{
+    errno = ENOTSUP;
+    return -1;
+}
+
+static inline ssize_t notsup_listxattr(FsContext *ctx, const char *path,
+                                       char *name, void *value, size_t size)
+{
+    return 0;
+}
+
+static inline int notsup_removexattr(FsContext *ctx,
+                                     const char *path, const char *name)
+{
+    errno = ENOTSUP;
+    return -1;
+}
+
 #endif