Introduce ul_set_log_flags()

Instead of piggy-backing on ul_openlog(), and accepting new flags at
openlog()-time, use a separate function, ul_set_log_flags() to achieve
the same.

This way, anyone who wants to flip any of the new flags, will have to
use ul_set_log_flags(), as ul_openlog() ignores them from now on.

This is based on work done by Miloslav Trmač <mitr@redhat.com>, and is
both an API and an ABI breakage.

Signed-off-by: Gergely Nagy <algernon@balabit.hu>

6 files changed, 180 insertions, 110 deletions

diff --git a/lib/libumberlog.ld b/lib/libumberlog.ld
index 225d51c..5b59d9d 100644
--- a/lib/libumberlog.ld
+++ b/lib/libumberlog.ld
@@ -20,3 +20,8 @@ LIBUMBERLOG_0.2.1 {
 	global:
           ul_closelog;
 } LIBUMBERLOG_0.1.0;
+
+LIBUMBERLOG_0.2.2 {
+	global:
+          ul_set_log_flags;
+} LIBUMBERLOG_0.2.1;
diff --git a/lib/umberlog.c b/lib/umberlog.c
index 3bb834a..be0b9d6 100644
--- a/lib/umberlog.c
+++ b/lib/umberlog.c
@@ -99,16 +99,10 @@ ul_finish (void)
   free (ul_buffer.msg);
 }
 
-void
-ul_openlog (const char *ident, int option, int facility)
+/* Must be called with ul_process_data.lock held. */
+static void
+_ul_reset_caches_locked (void)
 {
-  old_openlog (ident, option, facility);
-
-  pthread_mutex_lock (&ul_process_data.lock);
-  ul_process_data.flags = option;
-  ul_process_data.facility = facility;
-  ul_process_data.ident = ident;
-
   /* If either NODISCOVER or NOCACHE is set, don't cache stuff we
      won't use. */
   if ((ul_process_data.flags & (LOG_UL_NODISCOVER | LOG_UL_NOCACHE)) != 0)
@@ -137,6 +131,28 @@ ul_openlog (const char *ident, int option, int facility)
     }
 
   gethostname (ul_process_data.hostname, _POSIX_HOST_NAME_MAX);
+}
+
+void
+ul_set_log_flags (int flags)
+{
+  pthread_mutex_lock (&ul_process_data.lock);
+  ul_process_data.flags = flags;
+  _ul_reset_caches_locked ();
+  pthread_mutex_unlock (&ul_process_data.lock);
+}
+
+void
+ul_openlog (const char *ident, int option, int facility)
+{
+  old_openlog (ident, option, facility);
+
+  pthread_mutex_lock (&ul_process_data.lock);
+  ul_process_data.facility = facility;
+  ul_process_data.ident = ident;
+
+  _ul_reset_caches_locked ();
+
   pthread_mutex_unlock (&ul_process_data.lock);
 }
 
diff --git a/lib/umberlog.h b/lib/umberlog.h
index 1bb5a59..eca6bcd 100644
--- a/lib/umberlog.h
+++ b/lib/umberlog.h
@@ -42,6 +42,7 @@ char *ul_vformat (int priority, const char *msg_format, va_list ap)
   __attribute__((warn_unused_result));
 
 void ul_openlog (const char *ident, int option, int facility);
+void ul_set_log_flags (int flags);
 void ul_closelog (void);
 int ul_setlogmask (int mask);
 
diff --git a/lib/umberlog.rst b/lib/umberlog.rst
index 1c7b909..c3cdcb8 100644
--- a/lib/umberlog.rst
+++ b/lib/umberlog.rst
@@ -19,6 +19,7 @@ SYNOPSIS
    #include <umberlog.h>
 
    void ul_openlog (const char *ident, int option, int facility);
+   void ul_set_log_flags (int flags);
    void ul_closelog (void);
 
    int ul_syslog (int priority, const char *format, ....);
@@ -35,8 +36,10 @@ DESCRIPTION
 
 **ul_openlog()** is a wrapper around the original **openlog()**
 function, which opens a connection to the system logger for a
-program. The updated version adds support for a number of new option
-flags, described below.
+program.
+
+**ul_set_log_flags** is to be used to set any combination of the new
+log flags described below.
 
 **ul_closelog()** is similar to **ul_openlog()** in that it is a
 wrapper around the original **closelog()**.
@@ -117,8 +120,8 @@ into the payload:
 EXTRA OPTION FLAGS
 ==================
 
-The *option* argument to **ul_openlog()** is an OR of any of the
-original **openlog()** flags, and these:
+The *flag* argument to **ul_set_log_flags()** is an OR of any of these
+flags:
 
 LOG_UL_NODISCOVER
   Disable all automatic discovery, and only include the *message*,
diff --git a/t/test_umberlog.c b/t/test_umberlog.c
index 21ac50d..07b2d17 100644
--- a/t/test_umberlog.c
+++ b/t/test_umberlog.c
@@ -80,6 +80,144 @@ START_TEST (test_ul_openlog)
 }
 END_TEST
 
+START_TEST (test_ul_openlog_flag_ignore)
+{
+  char *msg;
+  struct json_object *jo;
+
+  ul_openlog ("umberlog/test_ul_openlog_flag_ignore", LOG_UL_NODISCOVER,
+              LOG_LOCAL0);
+
+  msg = ul_format (LOG_DEBUG, "hello, I'm %s!", __FUNCTION__, NULL);
+  jo = parse_msg (msg);
+  free (msg);
+
+  verify_value_exists (jo, "pid");
+  verify_value_exists (jo, "uid");
+  verify_value_exists (jo, "gid");
+  verify_value_exists (jo, "host");
+
+  json_object_put (jo);
+
+  ul_closelog ();
+}
+END_TEST
+
+START_TEST (test_ul_set_log_flags)
+{
+  char *msg;
+  struct json_object *jo;
+
+  ul_openlog ("umberlog/test_ul_set_log_flags", 0, LOG_LOCAL0);
+  ul_set_log_flags (LOG_UL_NODISCOVER);
+
+  msg = ul_format (LOG_DEBUG, "hello, I'm %s!", __FUNCTION__, NULL);
+  jo = parse_msg (msg);
+  free (msg);
+
+  verify_value_missing (jo, "pid");
+  verify_value_missing (jo, "uid");
+  verify_value_missing (jo, "gid");
+  verify_value_missing (jo, "host");
+
+  json_object_put (jo);
+
+  ul_closelog ();
+}
+END_TEST
+
+START_TEST (test_no_discover)
+{
+  char *msg;
+  struct json_object *jo;
+
+  ul_openlog ("umberlog/test_no_discover", 0, LOG_LOCAL0);
+  ul_set_log_flags (LOG_UL_NODISCOVER);
+
+  msg = ul_format (LOG_DEBUG, "hello, I'm %s!", __FUNCTION__, NULL);
+  jo = parse_msg (msg);
+  free (msg);
+
+  verify_value (jo, "msg", "hello, I'm test_no_discover!");
+  verify_value_missing (jo, "facility");
+  verify_value_missing (jo, "priority");
+  verify_value_missing (jo, "program");
+  verify_value_missing (jo, "pid");
+  verify_value_missing (jo, "uid");
+  verify_value_missing (jo, "gid");
+  verify_value_missing (jo, "host");
+  verify_value_missing (jo, "timestamp");
+
+  json_object_put (jo);
+
+  ul_closelog ();
+}
+END_TEST
+
+START_TEST (test_no_timestamp)
+{
+  char *msg;
+  struct json_object *jo;
+
+  ul_openlog ("umberlog/test_no_timestamp", 0, LOG_LOCAL0);
+  ul_set_log_flags (LOG_UL_NOTIME);
+
+  msg = ul_format (LOG_DEBUG, "hello, I'm %s!", __FUNCTION__, NULL);
+  jo = parse_msg (msg);
+  free (msg);
+
+  verify_value (jo, "msg", "hello, I'm test_no_timestamp!");
+  verify_value (jo, "facility", "local0");
+  verify_value (jo, "priority", "debug");
+  verify_value (jo, "program", "umberlog/test_no_timestamp");
+  verify_value_exists (jo, "pid");
+  verify_value_exists (jo, "uid");
+  verify_value_exists (jo, "gid");
+  verify_value_missing (jo, "timestamp");
+  verify_value_exists (jo, "host");
+
+  json_object_put (jo);
+
+  ul_closelog ();
+}
+END_TEST
+
+START_TEST (test_closelog)
+{
+  char *msg;
+  struct json_object *jo;
+
+  ul_openlog ("umberlog/test_closelog", 0, LOG_LOCAL0);
+  ul_set_log_flags (LOG_UL_NODISCOVER);
+  ul_closelog ();
+
+  msg = ul_format (LOG_DEBUG, "%s", __FUNCTION__, NULL);
+  jo = parse_msg (msg);
+  free (msg);
+
+  verify_value_missing (jo, "facility");
+
+  json_object_put (jo);
+
+  ul_openlog ("umberlog/test_closelog", 0, LOG_LOCAL0);
+  ul_closelog ();
+
+  msg = ul_format (LOG_DEBUG, "%s", __FUNCTION__, NULL);
+  jo = parse_msg (msg);
+  free (msg);
+
+  verify_value_missing (jo, "facility");
+  verify_value_missing (jo, "program");
+
+  verify_value_missing (jo, "pid");
+  verify_value_missing (jo, "uid");
+  verify_value_missing (jo, "gid");
+  verify_value_missing (jo, "host");
+
+  json_object_put (jo);
+}
+END_TEST
+
 int
 main (void)
 {
@@ -93,6 +231,10 @@ main (void)
   ft = tcase_create ("Basic tests");
   tcase_add_test (ft, test_overrides);
   tcase_add_test (ft, test_ul_openlog);
+  tcase_add_test (ft, test_ul_openlog_flag_ignore);
+  tcase_add_test (ft, test_ul_set_log_flags);
+  tcase_add_test (ft, test_closelog);
+  tcase_add_test (ft, test_no_discover);
   suite_add_tcase (s, ft);
 
   sr = srunner_create (s);
diff --git a/t/test_umberlog_preload.c b/t/test_umberlog_preload.c
index e931210..09d3210 100644
--- a/t/test_umberlog_preload.c
+++ b/t/test_umberlog_preload.c
@@ -44,33 +44,6 @@ START_TEST (test_simple)
 }
 END_TEST
 
-START_TEST (test_no_discover)
-{
-  char *msg;
-  struct json_object *jo;
-
-  openlog ("umberlog/test_no_discover", LOG_UL_NODISCOVER, LOG_LOCAL0);
-
-  msg = ul_format (LOG_DEBUG, "hello, I'm %s!", __FUNCTION__, NULL);
-  jo = parse_msg (msg);
-  free (msg);
-
-  verify_value (jo, "msg", "hello, I'm test_no_discover!");
-  verify_value_missing (jo, "facility");
-  verify_value_missing (jo, "priority");
-  verify_value_missing (jo, "program");
-  verify_value_missing (jo, "pid");
-  verify_value_missing (jo, "uid");
-  verify_value_missing (jo, "gid");
-  verify_value_missing (jo, "host");
-  verify_value_missing (jo, "timestamp");
-
-  json_object_put (jo);
-
-  closelog ();
-}
-END_TEST
-
 START_TEST (test_additional_fields)
 {
   char *msg;
@@ -121,33 +94,6 @@ START_TEST (test_discover_priority)
 }
 END_TEST
 
-START_TEST (test_no_timestamp)
-{
-  char *msg;
-  struct json_object *jo;
-
-  openlog ("umberlog/test_no_timestamp", LOG_UL_NOTIME, LOG_LOCAL0);
-
-  msg = ul_format (LOG_DEBUG, "hello, I'm %s!", __FUNCTION__, NULL);
-  jo = parse_msg (msg);
-  free (msg);
-
-  verify_value (jo, "msg", "hello, I'm test_no_timestamp!");
-  verify_value (jo, "facility", "local0");
-  verify_value (jo, "priority", "debug");
-  verify_value (jo, "program", "umberlog/test_no_timestamp");
-  verify_value_exists (jo, "pid");
-  verify_value_exists (jo, "uid");
-  verify_value_exists (jo, "gid");
-  verify_value_missing (jo, "timestamp");
-  verify_value_exists (jo, "host");
-
-  json_object_put (jo);
-
-  closelog ();
-}
-END_TEST
-
 START_TEST (test_json_escape)
 {
   static const char control_chars[] =
@@ -201,46 +147,6 @@ START_TEST (test_facprio)
 }
 END_TEST
 
-START_TEST (test_closelog)
-{
-  char *msg;
-  struct json_object *jo;
-
-  openlog ("umberlog/test_closelog", LOG_UL_NODISCOVER, LOG_LOCAL0);
-  closelog ();
-
-  msg = ul_format (LOG_DEBUG, "%s", __FUNCTION__, NULL);
-  jo = parse_msg (msg);
-  free (msg);
-
-  verify_value_missing (jo, "facility");
-
-  json_object_put (jo);
-
-  openlog ("umberlog/test_closelog", 0, LOG_LOCAL0);
-  closelog ();
-
-  msg = ul_format (LOG_DEBUG, "%s", __FUNCTION__, NULL);
-  jo = parse_msg (msg);
-  free (msg);
-
-  verify_value (jo, "facility", "local0");
-#ifdef HAVE_PROGRAM_INVOCATION_SHORT_NAME
-  verify_value (jo, "program", "test_umberlog_preload");
-#else
-  verify_value_missing (jo, "program");
-#endif
-  verify_value_differs (jo, "pid", "0");
-  if (getuid () != 0)
-    verify_value_differs (jo, "uid", "0");
-  if (getgid () != 0)
-    verify_value_differs (jo, "gid", "0");
-  verify_value_differs (jo, "host", "");
-
-  json_object_put (jo);
-}
-END_TEST
-
 #ifdef HAVE_PARSE_PRINTF_FORMAT
 START_TEST (test_positional_params)
 {
@@ -315,10 +221,8 @@ main (void)
   ft = tcase_create ("Basic tests");
   tcase_add_test (ft, test_openlog_defaults);
   tcase_add_test (ft, test_simple);
-  tcase_add_test (ft, test_no_discover);
   tcase_add_test (ft, test_additional_fields);
   tcase_add_test (ft, test_discover_priority);
-  tcase_add_test (ft, test_no_timestamp);
 #ifdef HAVE_PARSE_PRINTF_FORMAT
   tcase_add_test (ft, test_positional_params);
 #endif
@@ -327,7 +231,6 @@ main (void)
   bt = tcase_create ("Bug tests");
   tcase_add_test (bt, test_json_escape);
   tcase_add_test (bt, test_facprio);
-  tcase_add_test (bt, test_closelog);
   suite_add_tcase (s, bt);
 
   sr = srunner_create (s);