From 767439c55858d65bf6f5776b7fcd36cc1132565c Mon Sep 17 00:00:00 2001
From: David Lamparter <equinox@diac24.net>
Date: Mon, 2 Dec 2019 16:20:00 +0100
Subject: [PATCH] lib: mark some allocations as "active at exit"

In some cases we really don't want to clean up things even when exiting
(i.e. to keep the logging subsystem going.)  This adds a flag on MGROUPs
to indicate that.

[v2: add "(active at exit)" marker text to debug memstats-at-exit]
Signed-off-by: David Lamparter <equinox@diac24.net>
---
 lib/memory.c       |  3 ++-
 lib/memory.h       | 14 ++++++++++++--
 lib/zlog_targets.c | 16 ++++++++++++----
 3 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/lib/memory.c b/lib/memory.c
index 149e294d50..3a29404827 100644
--- a/lib/memory.c
+++ b/lib/memory.c
@@ -163,7 +163,8 @@ static int qmem_exit_walker(void *arg, struct memgroup *mg, struct memtype *mt)
 
 	} else if (mt->n_alloc) {
 		char size[32];
-		eda->error++;
+		if (!mg->active_at_exit)
+			eda->error++;
 		snprintf(size, sizeof(size), "%10zu", mt->size);
 		fprintf(eda->fp, "%s: memstats:  %-30s: %6zu * %s\n",
 			eda->prefix, mt->name, mt->n_alloc,
diff --git a/lib/memory.h b/lib/memory.h
index e4e05faa4f..13f2f9b11a 100644
--- a/lib/memory.h
+++ b/lib/memory.h
@@ -17,6 +17,7 @@
 #ifndef _QUAGGA_MEMORY_H
 #define _QUAGGA_MEMORY_H
 
+#include <stdbool.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <frratomic.h>
@@ -48,6 +49,8 @@ struct memgroup {
 	struct memgroup *next, **ref;
 	struct memtype *types, **insert;
 	const char *name;
+	/* ignore group on dumping memleaks at exit */
+	bool active_at_exit;
 };
 
 /* macro usage:
@@ -76,7 +79,7 @@ struct memgroup {
  */
 
 #define DECLARE_MGROUP(name) extern struct memgroup _mg_##name;
-#define DEFINE_MGROUP(mname, desc)                                             \
+#define _DEFINE_MGROUP(mname, desc, ...)                                       \
 	struct memgroup _mg_##mname                                            \
 		__attribute__((section(".data.mgroups"))) = {                  \
 			.name = desc,                                          \
@@ -84,6 +87,7 @@ struct memgroup {
 			.next = NULL,                                          \
 			.insert = NULL,                                        \
 			.ref = NULL,                                           \
+			__VA_ARGS__                                            \
 	};                                                                     \
 	static void _mginit_##mname(void) __attribute__((_CONSTRUCTOR(1000))); \
 	static void _mginit_##mname(void)                                      \
@@ -99,7 +103,13 @@ struct memgroup {
 		if (_mg_##mname.next)                                          \
 			_mg_##mname.next->ref = _mg_##mname.ref;               \
 		*_mg_##mname.ref = _mg_##mname.next;                           \
-	}
+	}                                                                      \
+	/* end */
+
+#define DEFINE_MGROUP(mname, desc) \
+	_DEFINE_MGROUP(mname, desc, )
+#define DEFINE_MGROUP_ACTIVEATEXIT(mname, desc) \
+	_DEFINE_MGROUP(mname, desc, .active_at_exit = true)
 
 #define DECLARE_MTYPE(name)                                                    \
 	extern struct memtype MTYPE_##name[1];                                 \
diff --git a/lib/zlog_targets.c b/lib/zlog_targets.c
index ff9cd1e5fe..85991b0dde 100644
--- a/lib/zlog_targets.c
+++ b/lib/zlog_targets.c
@@ -26,10 +26,18 @@
 #include "zlog.h"
 #include "zlog_targets.h"
 
-DEFINE_MTYPE_STATIC(LIB, LOG_FD,        "log file target")
-DEFINE_MTYPE_STATIC(LIB, LOG_FD_NAME,   "log file name")
-DEFINE_MTYPE_STATIC(LIB, LOG_FD_ROTATE, "log file rotate helper")
-DEFINE_MTYPE_STATIC(LIB, LOG_SYSL,      "syslog target")
+/* these allocations are intentionally left active even when doing full exit
+ * cleanup, in order to keep the logging subsystem fully functional until the
+ * absolute end.
+ */
+
+DECLARE_MGROUP(LOG)
+DEFINE_MGROUP_ACTIVEATEXIT(LOG, "logging subsystem")
+
+DEFINE_MTYPE_STATIC(LOG, LOG_FD,        "log file target")
+DEFINE_MTYPE_STATIC(LOG, LOG_FD_NAME,   "log file name")
+DEFINE_MTYPE_STATIC(LOG, LOG_FD_ROTATE, "log file rotate helper")
+DEFINE_MTYPE_STATIC(LOG, LOG_SYSL,      "syslog target")
 
 struct zlt_fd {
 	struct zlog_target zt;