fixes #2148 Old id_reg_map seems not be freed

This simplifies the code to just use a precompiled static list.
This should be lighter weight, and provably free from leaks.

7 files changed, 83 insertions, 71 deletions

diff --git a/src/core/defs.h b/src/core/defs.h
index 432c0be7..2ad489f6 100644
--- a/src/core/defs.h
+++ b/src/core/defs.h
@@ -1,5 +1,5 @@
 //
-// Copyright 2021 Staysail Systems, Inc. <info@staysail.tech>
+// Copyright 2025 Staysail Systems, Inc. <info@staysail.tech>
 // Copyright 2018 Capitar IT Group BV <info@capitoar.com>
 //
 // This software is supplied under the terms of the MIT License, a
@@ -67,7 +67,7 @@ typedef int32_t  nni_duration; // Rel. time (ms).
 typedef void (*nni_cb)(void *);
 
 // Some default timing things.
-#define NNI_TIME_NEVER ((nni_time) -1)
+#define NNI_TIME_NEVER ((nni_time) - 1)
 #define NNI_TIME_ZERO ((nni_time) 0)
 #define NNI_SECOND (1000)
 
@@ -239,4 +239,23 @@ typedef nni_type nni_opt_type;
 #endif // defined(__BYTE_ORDER)
 #endif // defined() endianness
 
+// nni_alloc allocates memory.  In most cases this can just be malloc().
+// However, you may provide a different allocator, for example it is
+// possible to use a slab allocator or somesuch.  It is permissible for this
+// to return NULL if memory cannot be allocated.
+extern void *nni_alloc(size_t);
+
+// nni_zalloc is just like nni_alloc, but ensures that memory is
+// initialized to zero.  It is a separate function because some platforms
+// can use a more efficient zero-based allocation.
+extern void *nni_zalloc(size_t);
+
+// nni_free frees memory allocated with nni_alloc or nni_zalloc. It takes
+// a size because some allocators do not track size, or can operate more
+// efficiently if the size is provided with the free call.  Examples of this
+// are slab allocators like this found in Solaris/illumos (see libumem).
+// This routine does nothing if supplied with a NULL pointer and zero size.
+// Most implementations can just call free() here.
+extern void nni_free(void *, size_t);
+
 #endif // CORE_DEFS_H
diff --git a/src/core/dialer.c b/src/core/dialer.c
index e422c642..bef110d7 100644
--- a/src/core/dialer.c
+++ b/src/core/dialer.c
@@ -22,7 +22,7 @@ static void dialer_connect_start(nni_dialer *);
 static void dialer_connect_cb(void *);
 static void dialer_timer_cb(void *);
 
-static nni_id_map dialers    = NNI_ID_MAP_INITIALIZER(1, 0x7fffffff, 0);
+static nni_id_map dialers    = NNI_ID_MAP_INITIALIZER(1, 0x7fffffff, false);
 static nni_mtx    dialers_lk = NNI_MTX_INITIALIZER;
 
 uint32_t
diff --git a/src/core/idhash.c b/src/core/idhash.c
index 73763a07..d3d3ec10 100644
--- a/src/core/idhash.c
+++ b/src/core/idhash.c
@@ -1,5 +1,5 @@
 //
-// Copyright 2024 Staysail Systems, Inc. <info@staysail.tech>
+// Copyright 2025 Staysail Systems, Inc. <info@staysail.tech>
 // Copyright 2018 Capitar IT Group BV <info@capitar.com>
 //
 // This software is supplied under the terms of the MIT License, a
@@ -8,7 +8,9 @@
 // found online at https://opensource.org/licenses/MIT.
 //
 
-#include "core/nng_impl.h"
+#include "idhash.h"
+#include "defs.h"
+#include "nng_impl.h"
 
 #include <string.h>
 
@@ -18,10 +20,19 @@ struct nni_id_entry {
 	void    *val;
 };
 
-static int          id_reg_len = 0;
-static int          id_reg_num = 0;
-static nni_id_map **id_reg_map = NULL;
-static nni_mtx      id_reg_mtx = NNI_MTX_INITIALIZER;
+// Maximum number of static maps permitted.
+// This static map initialization to be simpler, and
+// avoids an unnecessary heap allocation, at the cost of
+// being a compile time tunable.  At present there are
+// only a few (5) static idmaps defined.
+
+#ifndef NNI_MAX_STATIC_IDMAP
+#define NNI_MAX_STATIC_IDMAP 10
+#endif
+
+static int         id_reg_num = 0;
+static nni_id_map *id_reg_map[NNI_MAX_STATIC_IDMAP];
+static nni_mtx     id_reg_mtx = NNI_MTX_INITIALIZER;
 
 void
 nni_id_map_init(nni_id_map *m, uint64_t lo, uint64_t hi, bool randomize)
@@ -34,20 +45,18 @@ nni_id_map_init(nni_id_map *m, uint64_t lo, uint64_t hi, bool randomize)
 	}
 	NNI_ASSERT(lo != 0);
 	NNI_ASSERT(hi > lo);
-	m->id_entries  = NULL;
-	m->id_count    = 0;
-	m->id_load     = 0;
-	m->id_cap      = 0;
-	m->id_dyn_val  = 0;
-	m->id_max_load = 0;
-	m->id_min_load = 0; // never shrink below this
-	m->id_min_val  = lo;
-	m->id_max_val  = hi;
-	if (randomize) {
-		m->id_flags = NNI_ID_FLAG_RANDOM;
-	} else {
-		m->id_flags = 0;
-	}
+	m->id_entries    = NULL;
+	m->id_count      = 0;
+	m->id_load       = 0;
+	m->id_cap        = 0;
+	m->id_dyn_val    = 0;
+	m->id_max_load   = 0;
+	m->id_min_load   = 0; // never shrink below this
+	m->id_min_val    = lo;
+	m->id_max_val    = hi;
+	m->id_random     = randomize;
+	m->id_static     = false;
+	m->id_registered = false;
 }
 
 void
@@ -64,7 +73,7 @@ nni_id_map_fini(nni_id_map *m)
 // Inspired by Python dict implementation.  This probe will visit every
 // cell.  We always hash consecutively assigned IDs.  This requires that
 // the capacity is always a power of two.
-#define ID_NEXT(m, j) ((((j) *5) + 1) & (m->id_cap - 1))
+#define ID_NEXT(m, j) ((((j) * 5) + 1) & (m->id_cap - 1))
 #define ID_INDEX(m, j) ((j) & (m->id_cap - 1))
 
 static size_t
@@ -107,37 +116,20 @@ nni_id_get(nni_id_map *m, uint64_t id)
 	return (m->id_entries[index].val);
 }
 
-static int
+static void
 id_map_register(nni_id_map *m)
 {
-	if ((m->id_flags & (NNI_ID_FLAG_STATIC | NNI_ID_FLAG_REGISTER)) !=
-	    NNI_ID_FLAG_STATIC) {
-		return (0);
-	}
 	nni_mtx_lock(&id_reg_mtx);
-	if (id_reg_len <= id_reg_num) {
-		nni_id_map **mr;
-		int          len = id_reg_len;
-		if (len < 10) {
-			len = 10;
-		} else {
-			len *= 2;
-		}
-		mr = nni_zalloc(sizeof(nni_id_map *) * len);
-		if (mr == NULL) {
-			nni_mtx_unlock(&id_reg_mtx);
-			return (NNG_ENOMEM);
-		}
-		id_reg_len = len;
-		if (id_reg_map != NULL)
-			memcpy(
-			    mr, id_reg_map, id_reg_num * sizeof(nni_id_map *));
-		id_reg_map = mr;
+	// This check occurs under the lock although it probably
+	// is not strictly necessary.  This code is called infrequently.
+	if (!m->id_registered) {
+		// If this assertion fires, increase the tunable.
+		// It shouldn't happen unless we add a lot more static idmaps.
+		NNI_ASSERT(id_reg_num < NNI_MAX_STATIC_IDMAP);
+		m->id_registered         = true;
+		id_reg_map[id_reg_num++] = m;
 	}
-	id_reg_map[id_reg_num++] = m;
-	m->id_flags |= NNI_ID_FLAG_REGISTER;
 	nni_mtx_unlock(&id_reg_mtx);
-	return (0);
 }
 
 void
@@ -147,11 +139,9 @@ nni_id_map_sys_fini(void)
 	for (int i = 0; i < id_reg_num; i++) {
 		if (id_reg_map[i] != NULL) {
 			nni_id_map_fini(id_reg_map[i]);
+			id_reg_map[i] = NULL;
 		}
 	}
-	nni_free(id_reg_map, sizeof(nni_id_map *) * id_reg_len);
-	id_reg_map = NULL;
-	id_reg_len = 0;
 	id_reg_num = 0;
 	nni_mtx_unlock(&id_reg_mtx);
 }
@@ -164,7 +154,6 @@ id_resize(nni_id_map *m)
 	uint32_t      new_cap;
 	uint32_t      old_cap;
 	uint32_t      i;
-	int           rv;
 
 	if ((m->id_load < m->id_max_load) && (m->id_load >= m->id_min_load)) {
 		// No resize needed.
@@ -173,8 +162,8 @@ id_resize(nni_id_map *m)
 
 	// if it is a statically declared map, register it so that we
 	// will free it at finalization time
-	if ((rv = id_map_register(m)) != 0) {
-		return (rv);
+	if (m->id_static) {
+		id_map_register(m);
 	}
 
 	old_cap = m->id_cap;
@@ -328,7 +317,7 @@ nni_id_alloc(nni_id_map *m, uint64_t *idp, void *val)
 		return (NNG_ENOMEM);
 	}
 	if (m->id_dyn_val == 0) {
-		if (m->id_flags & NNI_ID_FLAG_RANDOM) {
+		if (m->id_random) {
 			// NB: The range is inclusive.
 			m->id_dyn_val = nni_random() %
 			        (m->id_max_val - m->id_min_val + 1) +
diff --git a/src/core/idhash.h b/src/core/idhash.h
index b07404aa..1d0c9b0e 100644
--- a/src/core/idhash.h
+++ b/src/core/idhash.h
@@ -1,5 +1,5 @@
 //
-// Copyright 2024 Staysail Systems, Inc. <info@staysail.tech>
+// Copyright 2025 Staysail Systems, Inc. <info@staysail.tech>
 // Copyright 2018 Capitar IT Group BV <info@capitar.com>
 //
 // This software is supplied under the terms of the MIT License, a
@@ -11,7 +11,7 @@
 #ifndef CORE_IDHASH_H
 #define CORE_IDHASH_H
 
-#include "core/defs.h"
+#include "defs.h"
 
 // We find that we often want to have a list of things listed by a
 // numeric ID, which is generally monotonically increasing.  This is
@@ -30,12 +30,14 @@ typedef struct nni_id_entry nni_id_entry;
 // They are provided here to facilitate inlining in structures.
 // We can support at most 2^32 ~ 4 billion ~ entries.
 struct nni_id_map {
-	uint32_t      id_flags;
 	uint32_t      id_cap;
 	uint32_t      id_count;
 	uint32_t      id_load;
 	uint32_t      id_min_load; // considers placeholders
 	uint32_t      id_max_load;
+	bool          id_static;
+	bool          id_registered;
+	bool          id_random;
 	uint64_t      id_min_val;
 	uint64_t      id_max_val;
 	uint64_t      id_dyn_val;
@@ -57,10 +59,13 @@ extern void     nni_id_map_sys_fini(void);
 extern bool     nni_id_visit(nni_id_map *, uint64_t *, void **, uint32_t *);
 extern uint32_t nni_id_count(const nni_id_map *);
 
-#define NNI_ID_MAP_INITIALIZER(min, max, flags)            \
-	{                                                  \
-		.id_min_val = (min), .id_max_val = (max),  \
-		.id_flags = ((flags) | NNI_ID_FLAG_STATIC) \
+#define NNI_ID_MAP_INITIALIZER(min, max, random) \
+	{                                        \
+		.id_min_val    = (min),          \
+		.id_max_val    = (max),          \
+		.id_static     = true,           \
+		.id_registered = false,          \
+		.id_random     = random,         \
 	}
 
 #endif // CORE_IDHASH_H
diff --git a/src/core/listener.c b/src/core/listener.c
index d1f3b497..cd10cb02 100644
--- a/src/core/listener.c
+++ b/src/core/listener.c
@@ -24,7 +24,7 @@ static void listener_accept_start(nni_listener *);
 static void listener_accept_cb(void *);
 static void listener_timer_cb(void *);
 
-static nni_id_map listeners    = NNI_ID_MAP_INITIALIZER(1, 0x7fffffff, 0);
+static nni_id_map listeners    = NNI_ID_MAP_INITIALIZER(1, 0x7fffffff, false);
 static nni_mtx    listeners_lk = NNI_MTX_INITIALIZER;
 
 uint32_t
diff --git a/src/core/pipe.c b/src/core/pipe.c
index 94520c39..bfc272b3 100644
--- a/src/core/pipe.c
+++ b/src/core/pipe.c
@@ -9,8 +9,8 @@
 // found online at https://opensource.org/licenses/MIT.
 //
 
-#include "core/nng_impl.h"
 #include "nng/nng.h"
+#include "nng_impl.h"
 #include "sockimpl.h"
 
 #include <stdio.h>
@@ -20,9 +20,8 @@
 // Operations on pipes (to the transport) are generally blocking operations,
 // performed in the context of the protocol.
 
-static nni_id_map pipes =
-    NNI_ID_MAP_INITIALIZER(1, 0x7fffffff, NNI_ID_FLAG_RANDOM);
-static nni_mtx pipes_lk = NNI_MTX_INITIALIZER;
+static nni_id_map pipes    = NNI_ID_MAP_INITIALIZER(1, 0x7fffffff, true);
+static nni_mtx    pipes_lk = NNI_MTX_INITIALIZER;
 
 static void pipe_destroy(void *);
 static void pipe_reap(void *);
diff --git a/src/core/socket.c b/src/core/socket.c
index 0e2e72ea..12373a6a 100644
--- a/src/core/socket.c
+++ b/src/core/socket.c
@@ -123,8 +123,8 @@ struct nni_socket {
 
 static nni_list sock_list  = NNI_LIST_INITIALIZER(sock_list, nni_sock, s_node);
 static nni_mtx  sock_lk    = NNI_MTX_INITIALIZER;
-static nni_id_map sock_ids = NNI_ID_MAP_INITIALIZER(1, 0x7fffffff, 0);
-static nni_id_map ctx_ids  = NNI_ID_MAP_INITIALIZER(1, 0x7fffffff, 0);
+static nni_id_map sock_ids = NNI_ID_MAP_INITIALIZER(1, 0x7fffffff, false);
+static nni_id_map ctx_ids  = NNI_ID_MAP_INITIALIZER(1, 0x7fffffff, false);
 
 static void nni_ctx_destroy(nni_ctx *);