[PATCH] libs/light: make it build without setresuid()

[Manuel Bouyer <bouyer@xxxxxxxxxxxxxxx>]

From: Manuel Bouyer <bouyer@xxxxxxxxxx>

NetBSD doesn't have setresuid(). Add a configure check for it,
and use plain setuid() if !HAVE_SETRESUID

Signed-off-by: Manuel Bouyer <bouyer@xxxxxxxxxx>
---
 tools/configure             | 13 +++++++++++++
 tools/configure.ac          |  3 +++
 tools/libs/light/libxl_dm.c | 10 ++++++++++
 3 files changed, 26 insertions(+)

diff --git a/tools/configure b/tools/configure
index 131112c41e..5e3793709e 100755
--- a/tools/configure
+++ b/tools/configure
@@ -9299,6 +9299,19 @@ _ACEOF
 
 esac
 
+# NetBSD doesnt have setresuid (yet)
+for ac_func in setresuid
+do :
+  ac_fn_c_check_func "$LINENO" "setresuid" "ac_cv_func_setresuid"
+if test "x$ac_cv_func_setresuid" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_SETRESUID 1
+_ACEOF
+
+fi
+done
+
+
 # Checks for header files.
 for ac_header in yajl/yajl_version.h sys/eventfd.h valgrind/memcheck.h utmp.h
 do :
diff --git a/tools/configure.ac b/tools/configure.ac
index ee8ba5ff24..04f78bf21d 100644
--- a/tools/configure.ac
+++ b/tools/configure.ac
@@ -457,6 +457,9 @@ AC_CHECK_DECLS([fdt_first_subnode, 
fdt_next_subnode],,,[#include <libfdt.h>])
 AC_CHECK_DECLS([fdt_property_u32],,,[#include <libfdt.h>])
 esac
 
+# NetBSD doesnt have setresuid (yet)
+AC_CHECK_FUNCS([setresuid])
+
 # Checks for header files.
 AC_CHECK_HEADERS([yajl/yajl_version.h sys/eventfd.h valgrind/memcheck.h 
utmp.h])
 
diff --git a/tools/libs/light/libxl_dm.c b/tools/libs/light/libxl_dm.c
index 8866c3f5ad..7651429b9f 100644
--- a/tools/libs/light/libxl_dm.c
+++ b/tools/libs/light/libxl_dm.c
@@ -3653,6 +3653,7 @@ static int 
kill_device_model_uid_child(libxl__destroy_devicemodel_state *ddms,
     assert(reaper_uid);
     assert(dm_kill_uid);
 
+#if HAVE_SETRESUID
     LOGD(DEBUG, domid, "DM reaper: calling setresuid(%d, %d, 0)",
          reaper_uid, dm_kill_uid);
     r = setresuid(reaper_uid, dm_kill_uid, 0);
@@ -3662,6 +3663,15 @@ static int 
kill_device_model_uid_child(libxl__destroy_devicemodel_state *ddms,
         rc = rc ?: ERROR_FAIL;
         goto out;
     }
+#else /* HAVE_SETRESUID */
+    LOGD(DEBUG, domid, "DM reaper: calling setuid(%d)", dm_kill_uid);
+    r = setuid(dm_kill_uid);
+    if (r) {
+        LOGED(ERROR, domid, "setuid to %d", dm_kill_uid);
+        rc = rc ?: ERROR_FAIL;
+        goto out;
+    }
+#endif /* HAVE_SETRESUID */
 
     /*
      * And kill everyone but me.
-- 
2.29.2