Guard one-time initialization with memory barriers

[nss_nonlocal.git] / nonlocal-passwd.c

diff --git a/nonlocal-passwd.c b/nonlocal-passwd.c
index 7529d9b886a1c45b08579add50aeb465c6259de4..f8e7f96f823ded1760977b01a28025ea8b851f43 100644 (file)
--- a/nonlocal-passwd.c
+++ b/nonlocal-passwd.c
@@ -25,18 +25,19 @@
 
 
 #define _GNU_SOURCE
+
 #include <sys/types.h>
-#include <unistd.h>
-#include <stdlib.h>
-#include <stdint.h>
-#include <string.h>
 #include <dlfcn.h>
-#include <stdio.h>
-#include <syslog.h>
 #include <errno.h>
-#include <pwd.h>
-#include <grp.h>
 #include <nss.h>
+#include <pwd.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <syslog.h>
+#include <unistd.h>
+
 #include "nsswitch-internal.h"
 #include "nonlocal.h"
 
@@ -161,6 +162,7 @@ get_nonlocal_passwd(const char *name, struct passwd *pwd, char **buffer,
 }
 
 
+static bool pwent_initialized = false;
 static service_user *pwent_startp, *pwent_nip;
 static void *pwent_fct_start;
 static union {
@@ -185,9 +187,12 @@ _nss_nonlocal_setpwent(int stayopen)
     if (status != NSS_STATUS_SUCCESS)
        return status;
 
-    if (pwent_fct_start == NULL)
+    if (!pwent_initialized) {
        __nss_passwd_nonlocal_lookup(&pwent_startp, pwent_fct_name,
                                     &pwent_fct_start);
+       __sync_synchronize();
+       pwent_initialized = true;
+    }
     pwent_nip = pwent_startp;
     pwent_fct.ptr = pwent_fct_start;
     return NSS_STATUS_SUCCESS;