File 0001-optionally-warn-if-nss-myhostname-is-called.diff of Package nss-myhostname

From 84a26d4ad7e43bd1c6675b8bd59e856b7e938f71 Mon Sep 17 00:00:00 2001
From: Ludwig Nussel <ludwig.nussel@suse.de>
Date: Fri, 20 May 2011 15:38:46 +0200
Subject: [PATCH nss-myhostname] optionally warn if nss-myhostname is called

---
 configure.ac     |    9 +++++++++
 nss-myhostname.c |   28 +++++++++++++++++++++++++++-
 2 files changed, 36 insertions(+), 1 deletions(-)

diff --git a/configure.ac b/configure.ac
index 38cd58f..e8c1503 100644
--- a/configure.ac
+++ b/configure.ac
@@ -72,6 +72,15 @@ AC_CHECK_FUNCS([gethostbyaddr gethostbyname gettimeofday inet_ntoa memset select
 # LYNX documentation generation
 ZP_LYNX_DOC
 
+AC_MSG_CHECKING([log warning messages])
+AC_ARG_WITH(warning, AS_HELP_STRING([--with-warning], [log warning to syslog when nss-myhostname is called (default=no)]),[],[with_warning=no])
+AC_MSG_RESULT([$with_warning])
+
+if test x$with_warning != xno; then
+	AC_CHECK_HEADERS([syslog.h])
+	AC_DEFINE([LOG_WARNING],[1],[whether to log warning message])
+fi
+
 AC_CONFIG_FILES([Makefile doc/Makefile doc/README.html ])
 
 AC_OUTPUT
diff --git a/nss-myhostname.c b/nss-myhostname.c
index 293166c..9d0e688 100644
--- a/nss-myhostname.c
+++ b/nss-myhostname.c
@@ -31,6 +31,9 @@
 #include <net/if.h>
 #include <stdlib.h>
 #include <arpa/inet.h>
+#if LOG_WARNING
+#include <syslog.h>
+#endif
 
 #include "netlink.h"
 
@@ -45,6 +48,8 @@
 
 #define ALIGN(a) (((a+sizeof(void*)-1)/sizeof(void*))*sizeof(void*))
 
+static void warn(const char* hn);
+
 enum nss_status _nss_myhostname_gethostbyname4_r(
                 const char *name,
                 struct gaih_addrtuple **pat,
@@ -117,6 +122,8 @@ enum nss_status _nss_myhostname_gethostbyname4_r(
                 return NSS_STATUS_NOTFOUND;
         }
 
+        warn(hn);
+
         /* If this fails, n_addresses is 0. Which is fine */
         netlink_acquire_addresses(&addresses, &n_addresses);
 
@@ -333,6 +340,8 @@ enum nss_status _nss_myhostname_gethostbyname3_r(
                 return NSS_STATUS_NOTFOUND;
         }
 
+        warn(hn);
+
         return fill_in_hostent(hn, af, host, buffer, buflen, errnop, h_errnop, ttlp, canonp);
 }
 
@@ -430,8 +439,9 @@ found:
                 return NSS_STATUS_UNAVAIL;
         }
 
-        return fill_in_hostent(hn, af, host, buffer, buflen, errnop, h_errnop, ttlp, NULL);
+        warn(hn);
 
+        return fill_in_hostent(hn, af, host, buffer, buflen, errnop, h_errnop, ttlp, NULL);
 }
 
 enum nss_status _nss_myhostname_gethostbyaddr_r(
@@ -449,3 +459,19 @@ enum nss_status _nss_myhostname_gethostbyaddr_r(
                         errnop, h_errnop,
                         NULL);
 }
+
+void warn(const char* hn) {
+#if LOG_WARNING
+        if (strstr(program_invocation_short_name, "nscd")) {
+                syslog(LOG_WARNING,
+                        "Some application tried to resolve hostname \"%s\" which is not in DNS. Stop nscd to find out which one.\n",
+                        hn);
+        } else {
+                syslog(LOG_WARNING,
+                        "%s(%u) tried to resolve hostname \"%s\" which is not in DNS. This might be the reason for the delays you experience.\n",
+                        program_invocation_short_name,
+                        getpid(),
+                        hn);
+        }
+#endif
+}
-- 
1.7.3.4