libs/light: make it build without setresuid()

NetBSD doesn't have setresuid(). introcuce libxl__setresuid(),
which on NetBSD assert() that it's never called (it should not be called when
dm restriction is off, and NetBSD doesn't support dm restriction at
this time).
On linux and FreeBSD it just calls setresuid().

Signed-off-by: Manuel Bouyer <bouyer@netbsd.org>
Reviewed-by: Ian Jackson <ian.jackson@eu.citrix.com>

diff --git a/tools/libs/light/Makefile b/tools/libs/light/Makefile
index 849d7e6863da7b3eb3e6c70a4204ff6d9c2beecf..216e2f55b0cda32a6e0f8e9262f3a7a22eefa638 100644 (file)
--- a/tools/libs/light/Makefile
+++ b/tools/libs/light/Makefile
@@ -64,8 +64,8 @@ SRCS-$(CONFIG_ARM) += libxl_arm_no_acpi.c
 endif
 
 SRCS-OS-$(CONFIG_NetBSD) = libxl_netbsd.c
-SRCS-OS-$(CONFIG_Linux) = libxl_linux.c
-SRCS-OS-$(CONFIG_FreeBSD) = libxl_freebsd.c
+SRCS-OS-$(CONFIG_Linux) = libxl_linux.c libxl_setresuid.c
+SRCS-OS-$(CONFIG_FreeBSD) = libxl_freebsd.c libxl_setresuid.c
 ifeq ($(SRCS-OS-y),)
 $(error Your Operating System is not supported by libxenlight, \
 please check libxl_linux.c and libxl_netbsd.c to see how to get it ported)

diff --git a/tools/libs/light/libxl_dm.c b/tools/libs/light/libxl_dm.c
index 3da83259c08e8bec51fe44a680f8f37301080338..45a0504a2ec585158d4a58ac38f548575edc45a5 100644 (file)
--- a/tools/libs/light/libxl_dm.c
+++ b/tools/libs/light/libxl_dm.c
@@ -3649,7 +3649,7 @@ static int kill_device_model_uid_child(libxl__destroy_devicemodel_state *ddms,
 
     LOGD(DEBUG, domid, "DM reaper: calling setresuid(%d, %d, 0)",
          reaper_uid, dm_kill_uid);
-    r = setresuid(reaper_uid, dm_kill_uid, 0);
+    r = libxl__setresuid(reaper_uid, dm_kill_uid, 0);
     if (r) {
         LOGED(ERROR, domid, "setresuid to (%d, %d, 0)",
               reaper_uid, dm_kill_uid);

diff --git a/tools/libs/light/libxl_internal.h b/tools/libs/light/libxl_internal.h
index 6c8b7d71a96a9af31c32df35da74168f2ab159a3..028bc013d9c5ddbb31e6f4eda3190d97502cc2f9 100644 (file)
--- a/tools/libs/light/libxl_internal.h
+++ b/tools/libs/light/libxl_internal.h
@@ -4845,6 +4845,9 @@ _hidden int libxl__domain_pvcontrol(libxl__egc *egc,
 /* Check whether a domid is recent */
 int libxl__is_domid_recent(libxl__gc *gc, uint32_t domid, bool *recent);
 
+/* os-specific implementation of setresuid() */
+int libxl__setresuid(uid_t ruid, uid_t euid, uid_t suid);
+
 #endif
 
 /*

diff --git a/tools/libs/light/libxl_netbsd.c b/tools/libs/light/libxl_netbsd.c
index 6ad4ed34c240c7908aabbc9689e9228d122bf60f..33cce5e9f6212e43ef9efbfbc206d289f0f3e096 100644 (file)
--- a/tools/libs/light/libxl_netbsd.c
+++ b/tools/libs/light/libxl_netbsd.c
@@ -124,3 +124,9 @@ int libxl__local_dm_preexec_restrict(libxl__gc *gc)
 {
     return 0;
 }
+
+int libxl__setresuid(uid_t ruid, uid_t euid, uid_t suid)
+{
+    assert(!"setresuid is not available on NetBSD, and dm restrction is not supported, so this code path should not have been reached");
+    return -1;
+}

diff --git a/tools/libs/light/libxl_setresuid.c b/tools/libs/light/libxl_setresuid.c
new file mode 100644 (file)
index 0000000..38d8612
--- /dev/null
+++ b/tools/libs/light/libxl_setresuid.c
@@ -0,0 +1,23 @@
+/*
+ * Copyright (C) 2021
+ * Author Manuel Bouyer <bouyer@netbsd.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation; version 2.1 only. with the special
+ * exception on linking described in file LICENSE.
+ *
+ * This program 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 Lesser General Public License for more details.
+ */
+
+#include "libxl_osdeps.h" /* must come before any other headers */
+
+#include "libxl_internal.h"
+
+int libxl__setresuid(uid_t ruid, uid_t euid, uid_t suid)
+{
+    return setresuid(ruid, euid, suid);
+}