lib: rewrite zlog lock-free & TLS-buffered

This is a full rewrite of the "back end" logging code.  It now uses a
lock-free list to iterate over logging targets, and the targets
themselves are as lock-free as possible.  (syslog() may have a hidden
internal mutex in the C library;  the file/fd targets use a single
write() call which should ensure atomicity kernel-side.)

Note that some functionality is lost in this patch:
- Solaris printstack() backtraces are ditched (unlikely to come back)
- the `log-filter` machinery is gone (re-added in followup commit)
- `terminal monitor` is temporarily stubbed out.  The old code had a
  race condition with VTYs going away.  It'll likely come back rewritten
  and with vtysh support.
- The `zebra_ext_log` hook is gone.  Instead, it's now much easier to
  add a "proper" logging target.

v2: TLS buffer to get some actual performance

Signed-off-by: David Lamparter <equinox@diac24.net>

6 files changed, 6 insertions, 28 deletions

diff --git a/tests/bgpd/test_peer_attr.c b/tests/bgpd/test_peer_attr.c
index 422d39747..631ce5a11 100644
--- a/tests/bgpd/test_peer_attr.c
+++ b/tests/bgpd/test_peer_attr.c
@@ -1381,8 +1381,7 @@ static void test_peer_attr(struct test *test, struct test_peer_attr *pa)
 static void bgp_startup(void)
 {
 	cmd_init(1);
-	openzlog("testbgpd", "NONE", 0, LOG_CONS | LOG_NDELAY | LOG_PID,
-		 LOG_DAEMON);
+	zlog_aux_init("NONE: ", LOG_DEBUG);
 	zprivs_preinit(&bgpd_privs);
 	zprivs_init(&bgpd_privs);
 
@@ -1438,7 +1437,6 @@ static void bgp_shutdown(void)
 	zprivs_terminate(&bgpd_privs);
 	thread_master_free(master);
 	master = NULL;
-	closezlog();
 }
 
 int main(void)
diff --git a/tests/lib/cli/common_cli.c b/tests/lib/cli/common_cli.c
index e091372ab..3302bb3d1 100644
--- a/tests/lib/cli/common_cli.c
+++ b/tests/lib/cli/common_cli.c
@@ -53,7 +53,6 @@ static void vty_do_exit(int isexit)
 	nb_terminate();
 	yang_terminate();
 	thread_master_free(master);
-	closezlog();
 
 	log_memstats(stderr, "testcli");
 	if (!isexit)
@@ -71,11 +70,7 @@ int main(int argc, char **argv)
 	/* master init. */
 	master = thread_master_create(NULL);
 
-	openzlog("common-cli", "NONE", 0, LOG_CONS | LOG_NDELAY | LOG_PID,
-		 LOG_DAEMON);
-	zlog_set_level(ZLOG_DEST_SYSLOG, ZLOG_DISABLED);
-	zlog_set_level(ZLOG_DEST_STDOUT, ZLOG_DISABLED);
-	zlog_set_level(ZLOG_DEST_MONITOR, LOG_DEBUG);
+	zlog_aux_init("NONE: ", ZLOG_DISABLED);
 
 	/* Library inits. */
 	cmd_init(1);
diff --git a/tests/lib/northbound/test_oper_data.c b/tests/lib/northbound/test_oper_data.c
index 18d318088..52216ea38 100644
--- a/tests/lib/northbound/test_oper_data.c
+++ b/tests/lib/northbound/test_oper_data.c
@@ -374,7 +374,6 @@ static void vty_do_exit(int isexit)
 	nb_terminate();
 	yang_terminate();
 	thread_master_free(master);
-	closezlog();
 
 	log_memstats(stderr, "test-nb-oper-data");
 	if (!isexit)
@@ -402,11 +401,7 @@ int main(int argc, char **argv)
 	/* master init. */
 	master = thread_master_create(NULL);
 
-	openzlog("test-nb-oper-data", "NONE", 0,
-		 LOG_CONS | LOG_NDELAY | LOG_PID, LOG_DAEMON);
-	zlog_set_level(ZLOG_DEST_SYSLOG, ZLOG_DISABLED);
-	zlog_set_level(ZLOG_DEST_STDOUT, ZLOG_DISABLED);
-	zlog_set_level(ZLOG_DEST_MONITOR, LOG_DEBUG);
+	zlog_aux_init("NONE: ", ZLOG_DISABLED);
 
 	/* Library inits. */
 	cmd_init(1);
diff --git a/tests/lib/test_segv.c b/tests/lib/test_segv.c
index 43ca0837d..8133637ad 100644
--- a/tests/lib/test_segv.c
+++ b/tests/lib/test_segv.c
@@ -73,11 +73,7 @@ int main(void)
 	master = thread_master_create(NULL);
 	signal_init(master, array_size(sigs), sigs);
 
-	openzlog("testsegv", "NONE", 0, LOG_CONS | LOG_NDELAY | LOG_PID,
-		 LOG_DAEMON);
-	zlog_set_level(ZLOG_DEST_SYSLOG, ZLOG_DISABLED);
-	zlog_set_level(ZLOG_DEST_STDOUT, LOG_DEBUG);
-	zlog_set_level(ZLOG_DEST_MONITOR, ZLOG_DISABLED);
+	zlog_aux_init("NONE: ", LOG_DEBUG);
 
 	thread_execute(master, threadfunc, 0, 0);
 
diff --git a/tests/lib/test_sig.c b/tests/lib/test_sig.c
index cf63a3d04..2aceafb8f 100644
--- a/tests/lib/test_sig.c
+++ b/tests/lib/test_sig.c
@@ -57,11 +57,7 @@ int main(void)
 	master = thread_master_create(NULL);
 	signal_init(master, array_size(sigs), sigs);
 
-	openzlog("testsig", "NONE", 0, LOG_CONS | LOG_NDELAY | LOG_PID,
-		 LOG_DAEMON);
-	zlog_set_level(ZLOG_DEST_SYSLOG, ZLOG_DISABLED);
-	zlog_set_level(ZLOG_DEST_STDOUT, LOG_DEBUG);
-	zlog_set_level(ZLOG_DEST_MONITOR, ZLOG_DISABLED);
+	zlog_aux_init("NONE: ", LOG_DEBUG);
 
 	while (thread_fetch(master, &t))
 		thread_call(&t);
diff --git a/tests/lib/test_zlog.c b/tests/lib/test_zlog.c
index 07885d984..3042cc6cc 100644
--- a/tests/lib/test_zlog.c
+++ b/tests/lib/test_zlog.c
@@ -52,9 +52,7 @@ bool (*tests[])(void) = {
 
 int main(int argc, char **argv)
 {
-	openzlog("testzlog", "NONE", 0, LOG_CONS | LOG_NDELAY | LOG_PID,
-		 LOG_ERR);
-	zlog_set_file("test_zlog.log", LOG_DEBUG);
+	zlog_aux_init("NONE: ", ZLOG_DISABLED);
 
 	for (unsigned int i = 0; i < array_size(tests); i++)
 		if (!tests[i]())