From 5f75f566ce6c1f82f5af749c7109232a76686ffc Mon Sep 17 00:00:00 2001
From: Bjarne von Horn <vh@igh.de>
Date: Wed, 12 Mar 2025 14:08:26 +0100
Subject: [PATCH] Create rtipc directories on startup

---
 fake_lib/README.md        |  3 ++-
 fake_lib/fakeethercat.cpp | 31 ++++++++++++++++++++++++++++---
 2 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/fake_lib/README.md b/fake_lib/README.md
index 0b8c76d9..3ceb1a91 100644
--- a/fake_lib/README.md
+++ b/fake_lib/README.md
@@ -65,13 +65,14 @@ export FAKE_EC_HOMEDIR=/tmp/FakeEtherCAT
 rm -rf $FAKE_EC_HOMEDIR
 mkdir -p $FAKE_EC_HOMEDIR
 ```
+For each master instance, one subdirectory named by the master id is created.
 
 ### Spin up your application
 
 Now it's time to simply launch your application.
 You will notice that the PDO configuration will be dumped at stderr.
 The path displayed is the path of the RtIPC variable in the following format:
-`$FAKE_EC_PREFIX/$MASTER_ID/$DOMAIN_ID/$ALIAS$POSITION/$PDO`.
+`$FAKE_EC_PREFIX/$MASTER_ID/$ALIAS$POSITION/$PDO`.
 
 ## How to emulate EtherCAT slaves
 
diff --git a/fake_lib/fakeethercat.cpp b/fake_lib/fakeethercat.cpp
index 80f769d1..ca588db8 100644
--- a/fake_lib/fakeethercat.cpp
+++ b/fake_lib/fakeethercat.cpp
@@ -30,6 +30,7 @@
 #include <unordered_set>
 #include <iterator>
 #include <ios>
+#include <sys/stat.h>
 
 static std::ostream &operator<<(std::ostream &os, const sdo_address &a)
 {
@@ -420,13 +421,37 @@ static const char *getName()
     return "FakeEtherCAT";
 }
 
+static int mkpath(const std::string &file_path)
+{
+    if (file_path.empty())
+        return 0;
+
+    std::size_t offset = 0;
+    do
+    {
+        offset = file_path.find('/', offset + 1);
+        const auto subpath = file_path.substr(0, offset);
+        if (mkdir(subpath.c_str(), 0755) == -1)
+        {
+            if (errno != EEXIST)
+            {
+                return -1;
+            }
+        }
+    } while (offset != std::string::npos);
+    return 0;
+}
+
 static std::string getRtIpcDir(int idx)
 {
-    if (const auto ans = getenv("FAKE_EC_HOMEDIR"))
+    std::string ans;
+    if (const auto e = getenv("FAKE_EC_HOMEDIR"))
     {
-        return ans + std::string("/") + std::to_string(idx);
+        ans = e + std::string("/") + std::to_string(idx);
     }
-    return "/tmp/FakeEtherCAT/" + std::to_string(idx);
+    ans = "/tmp/FakeEtherCAT/" + std::to_string(idx);
+    mkpath(ans);
+    return ans;
 }
 
 ec_master::ec_master(int id) : rt_ipc_dir(getRtIpcDir(id)), rt_ipc_name(getName()), rt_ipc(rtipc_create(rt_ipc_name.c_str(), rt_ipc_dir.c_str())), id_(id)