From 3b3a0da33b23b9faf02f6aaf4ecebad8a50411ee Mon Sep 17 00:00:00 2001
From: Jakob Hoellerbauer <jakob.hoellerbauer@skyspecs.com>
Date: Tue, 7 Oct 2025 14:05:20 -0400
Subject: [PATCH 1/3] Optionally try to load libzmq in java

---
 zcm/java/zcm/zcm/ZCMNativeLoader.java | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/zcm/java/zcm/zcm/ZCMNativeLoader.java b/zcm/java/zcm/zcm/ZCMNativeLoader.java
index a8223c7a..69b2598c 100644
--- a/zcm/java/zcm/zcm/ZCMNativeLoader.java
+++ b/zcm/java/zcm/zcm/ZCMNativeLoader.java
@@ -25,6 +25,11 @@ public static void loadLibrary() {
         if (!isLoaded) {
             synchronized (lock) {
                 if (!isLoaded) {
+                    try {
+                        System.loadLibrary("zmq");
+                    } catch (UnsatisfiedLinkError e) {
+                        System.err.println("Could not find libzmq : "+e);
+                    }
                     try {
                         System.loadLibrary("zcm");
                     } catch (UnsatisfiedLinkError e) {

From 4a156721fcfcb9d34b5f4f29a0a062aa0f88e5d8 Mon Sep 17 00:00:00 2001
From: Jakob Hoellerbauer <jakob.hoellerbauer@skyspecs.com>
Date: Tue, 7 Oct 2025 18:14:09 -0400
Subject: [PATCH 2/3] Make base directory for zmq sockets configurable

---
 zcm/transport/transport_zmq_local.cpp | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/zcm/transport/transport_zmq_local.cpp b/zcm/transport/transport_zmq_local.cpp
index 71e812ce..a4e19f58 100644
--- a/zcm/transport/transport_zmq_local.cpp
+++ b/zcm/transport/transport_zmq_local.cpp
@@ -60,6 +60,7 @@ struct ZCM_TRANS_CLASSNAME : public zcm_trans_t
     string subnet;
     int pubhwm = 1000, subhwm = 1000;
     uint64_t rescanPeriodUs = 250e3;
+    string baseDir;
 
     unordered_map<string, pair<void*,lockfile_t*>> pubsocks;
     // socket pair contains the socket + whether it was subscribed to explicitly or not
@@ -101,13 +102,24 @@ struct ZCM_TRANS_CLASSNAME : public zcm_trans_t
         auto* subhwmStr = findOption("subhwm");
         if (subhwmStr) subhwm = atoi(subhwmStr->c_str());
 
+        auto* baseDirStr = findOption("base_dir");
+        if (baseDirStr) {
+            baseDir = *baseDirStr;
+        } else {
+            baseDir = "/tmp";
+        }
+
         auto* rescanPeriodUsStr = findOption("rescan_period_us");
         if (rescanPeriodUsStr) rescanPeriodUs = atoi(rescanPeriodUsStr->c_str());
 
         subnet = zcm_url_address(url);
 
+        string fullPath = string(baseDir + "/" + subnet);
         // Make directory with all permissions
-        mkdir(string("/tmp/" + subnet).c_str(), S_IRWXO | S_IRWXG | S_IRWXU);
+        int ret = mkdir(fullPath.c_str(), S_IRWXO | S_IRWXG | S_IRWXU);
+        if (ret < 0 && errno != EEXIST) {
+            ZCM_DEBUG("Subnet directory creation failed! Could not create %s: %s", fullPath.c_str(), strerror(errno));
+        }
 
         ZCM_DEBUG("ZMQ Subnet Address: %s\n", subnet.c_str());
 
@@ -178,7 +190,7 @@ struct ZCM_TRANS_CLASSNAME : public zcm_trans_t
     {
         switch (type) {
             case IPC:
-                return "ipc:///tmp/" + subnet + "/" + IPC_NAME_PREFIX + channel;
+                return "ipc://" + baseDir + "/" + subnet + "/" + IPC_NAME_PREFIX + channel;
             case INPROC:
                 return "inproc://" + subnet + "/" + IPC_NAME_PREFIX + channel;
         }
@@ -286,7 +298,7 @@ struct ZCM_TRANS_CLASSNAME : public zcm_trans_t
         DIR *d;
         dirent *ent;
 
-        if (!(d=opendir(string("/tmp/" + subnet).c_str())))
+        if (!(d=opendir(string(baseDir + "/" + subnet).c_str())))
             return;
 
         while ((ent=readdir(d)) != nullptr) {
@@ -542,7 +554,7 @@ static zcm_trans_t *createInproc(zcm_url_t *url, char **opt_errmsg)
 const TransportRegister ZCM_TRANS_CLASSNAME::regIpc(
     "ipc", "Transfer data via Inter-process Communication "
            "(e.g. 'ipc' or "
-           "'ipc://<subnet>?rescan_period_us=250000')",
+           "'ipc://<subnet>?rescan_period_us=250000?base_dir=/tmp')",
     createIpc);
 #endif
 

From f4de30f4e3e56cc8d75d066f81ecb5cdb1c1dd61 Mon Sep 17 00:00:00 2001
From: Jakob Hoellerbauer <jakob.hoellerbauer@skyspecs.com>
Date: Wed, 8 Oct 2025 11:45:32 -0400
Subject: [PATCH 3/3] Reviewed

---
 zcm/java/zcm/zcm/ZCMNativeLoader.java | 4 +---
 zcm/transport/transport_zmq_local.cpp | 6 ++++--
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/zcm/java/zcm/zcm/ZCMNativeLoader.java b/zcm/java/zcm/zcm/ZCMNativeLoader.java
index 69b2598c..afb4dc94 100644
--- a/zcm/java/zcm/zcm/ZCMNativeLoader.java
+++ b/zcm/java/zcm/zcm/ZCMNativeLoader.java
@@ -27,9 +27,7 @@ public static void loadLibrary() {
                 if (!isLoaded) {
                     try {
                         System.loadLibrary("zmq");
-                    } catch (UnsatisfiedLinkError e) {
-                        System.err.println("Could not find libzmq : "+e);
-                    }
+                    } catch (UnsatisfiedLinkError e) {}
                     try {
                         System.loadLibrary("zcm");
                     } catch (UnsatisfiedLinkError e) {
diff --git a/zcm/transport/transport_zmq_local.cpp b/zcm/transport/transport_zmq_local.cpp
index a4e19f58..b02516dc 100644
--- a/zcm/transport/transport_zmq_local.cpp
+++ b/zcm/transport/transport_zmq_local.cpp
@@ -118,7 +118,9 @@ struct ZCM_TRANS_CLASSNAME : public zcm_trans_t
         // Make directory with all permissions
         int ret = mkdir(fullPath.c_str(), S_IRWXO | S_IRWXG | S_IRWXU);
         if (ret < 0 && errno != EEXIST) {
-            ZCM_DEBUG("Subnet directory creation failed! Could not create %s: %s", fullPath.c_str(), strerror(errno));
+            ZCM_DEBUG("Subnet directory creation failed! Could not create %s: %s",
+                      fullPath.c_str(), strerror(errno));
+            assert(false && "ZMQ dir creation failed");
         }
 
         ZCM_DEBUG("ZMQ Subnet Address: %s\n", subnet.c_str());
@@ -554,7 +556,7 @@ static zcm_trans_t *createInproc(zcm_url_t *url, char **opt_errmsg)
 const TransportRegister ZCM_TRANS_CLASSNAME::regIpc(
     "ipc", "Transfer data via Inter-process Communication "
            "(e.g. 'ipc' or "
-           "'ipc://<subnet>?rescan_period_us=250000?base_dir=/tmp')",
+           "'ipc://<subnet>?rescan_period_us=250000&base_dir=/tmp')",
     createIpc);
 #endif