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>

1 files changed, 8 insertions, 6 deletions

diff --git a/lib/libfrr.c b/lib/libfrr.c
index 3622890e46..084ab93a4e 100644
--- a/lib/libfrr.c
+++ b/lib/libfrr.c
@@ -33,7 +33,6 @@
 #include "lib_vty.h"
 #include "log_vty.h"
 #include "zclient.h"
-#include "log_int.h"
 #include "module.h"
 #include "network.h"
 #include "lib_errors.h"
@@ -630,6 +629,7 @@ struct thread_master *frr_init(void)
 {
 	struct option_chain *oc;
 	struct frrmod_runtime *module;
+	struct zprivs_ids_t ids;
 	char moderr[256];
 	char p_instance[16] = "", p_pathspace[256] = "";
 	const char *dir;
@@ -657,9 +657,11 @@ struct thread_master *frr_init(void)
 #endif
 
 	zprivs_preinit(di->privs);
+	zprivs_get_ids(&ids);
 
-	openzlog(di->progname, di->logname, di->instance,
-		 LOG_CONS | LOG_NDELAY | LOG_PID, LOG_DAEMON);
+	zlog_init(di->progname, di->logname, di->instance,
+		  ids.uid_normal, ids.gid_normal);
+	zlog_tls_buffer_init();
 
 	command_setup_early_logging(di->early_logging, di->early_loglevel);
 
@@ -709,7 +711,6 @@ struct thread_master *frr_init(void)
 
 	vty_init(master, di->log_always);
 	lib_cmd_init();
-	log_filter_cmd_init();
 
 	frr_pthread_init();
 
@@ -1086,7 +1087,7 @@ void frr_run(struct thread_master *master)
 	}
 
 	/* end fixed stderr startup logging */
-	zlog_startup_stderr = false;
+	zlog_startup_end();
 
 	struct thread thread;
 	while (thread_fetch(master, &thread))
@@ -1119,7 +1120,8 @@ void frr_fini(void)
 	/* signal_init -> nothing needed */
 	thread_master_free(master);
 	master = NULL;
-	closezlog();
+	zlog_tls_buffer_fini();
+	zlog_fini();
 	/* frrmod_init -> nothing needed / hooks */
 	rcu_shutdown();