From 560dbe7fc75ada18a909c261a07bcb701254d899 Mon Sep 17 00:00:00 2001
From: Julien Letessier <julien.letessier@gmail.com>
Date: Thu, 15 Jan 2026 16:11:30 +0100
Subject: [PATCH] Cap log unit allocation in logger

---
 src/Logger.cpp                    |  4 ++-
 src/Logger.h                      |  4 +++
 test/logger_unbounded_logunit.cpp | 18 ++++++++++++
 test/logger_unbounded_logunit.py  | 47 +++++++++++++++++++++++++++++++
 test/run.sh                       |  1 +
 5 files changed, 73 insertions(+), 1 deletion(-)
 create mode 100644 test/logger_unbounded_logunit.cpp
 create mode 100644 test/logger_unbounded_logunit.py

diff --git a/src/Logger.cpp b/src/Logger.cpp
index 22b92f0..d951660 100644
--- a/src/Logger.cpp
+++ b/src/Logger.cpp
@@ -197,6 +197,7 @@ LogUnit* Logger::getLogUnit()
             mFree.resize(mFree.size() - 1);
         } else if (mLogUnitCnt < mFree.capacity()) {
             ++mLogUnitCnt;
+            log = new LogUnit();
         } else {
             ++mMissLogs;
             return nullptr;
@@ -208,6 +209,7 @@ LogUnit* Logger::getLogUnit()
             mFree.resize(mFree.size() - 1);
         } else if (mLogUnitCnt < mFree.capacity()) {
             ++mLogUnitCnt;
+            log = new LogUnit();
         } else {
             while (mFree.empty() && !mStop) {
                 mCond.wait(lck);
@@ -220,7 +222,7 @@ LogUnit* Logger::getLogUnit()
             }
         }
     }
-    return log ? log : new LogUnit();
+    return log;
 }
 
 int Logger::logFileFd() const
diff --git a/src/Logger.h b/src/Logger.h
index 3b04e05..24c6e69 100644
--- a/src/Logger.h
+++ b/src/Logger.h
@@ -92,6 +92,10 @@ public:
     }
     void log(LogLevel::Type lvl, const char* file, int line, const char* fmt, ...);
     int logFileFd() const;
+    unsigned logUnitCount() const
+    {
+        return mLogUnitCnt;
+    }
     static Logger* gInst;
 private:
     LogUnit* getLogUnit();
diff --git a/test/logger_unbounded_logunit.cpp b/test/logger_unbounded_logunit.cpp
new file mode 100644
index 0000000..093edae
--- /dev/null
+++ b/test/logger_unbounded_logunit.cpp
@@ -0,0 +1,18 @@
+/*
+ * Ensure Logger does not create more LogUnit instances than its capacity.
+ */
+
+#include "../src/Logger.h"
+
+int main() {
+    Logger logger(1);
+    logger.setAllowMissLog(true);
+    logger.setLogSample(LogLevel::Info, 1);
+    for (int i = 0; i < 1000; ++i) {
+        logger.log(LogLevel::Info, __FILE__, __LINE__, "msg %d", i);
+    }
+    if (logger.logUnitCount() > 1) {
+        return 1;
+    }
+    return 0;
+}
diff --git a/test/logger_unbounded_logunit.py b/test/logger_unbounded_logunit.py
new file mode 100644
index 0000000..8484287
--- /dev/null
+++ b/test/logger_unbounded_logunit.py
@@ -0,0 +1,47 @@
+#!/usr/bin/env python3
+#
+# Build and run the Logger LogUnit cap test.
+#
+
+import os
+import subprocess
+import tempfile
+from test_util import parse_args, exit_with_result
+
+
+def run_test(project_root):
+    src = os.path.join(project_root, "test", "logger_unbounded_logunit.cpp")
+    if not os.path.exists(src):
+        print("FAIL: logger_unbounded_logunit.cpp not found")
+        return False
+
+    with tempfile.TemporaryDirectory() as tmp:
+        exe = os.path.join(tmp, "logger_unbounded_logunit")
+        cmd = [
+            "g++",
+            "-std=c++11",
+            src,
+            os.path.join(project_root, "src", "Logger.cpp"),
+            os.path.join(project_root, "src", "LogFileSink.cpp"),
+            os.path.join(project_root, "src", "Timer.cpp"),
+            "-o",
+            exe,
+        ]
+        try:
+            subprocess.check_call(cmd, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
+        except Exception as exc:
+            print("FAIL: compile logger_unbounded_logunit:", exc)
+            return False
+        try:
+            subprocess.check_call([exe], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
+        except subprocess.CalledProcessError as exc:
+            print("FAIL: logger_unbounded_logunit returned", exc.returncode)
+            return False
+    return True
+
+
+if __name__ == "__main__":
+    _ = parse_args("Logger logunit cap test")
+    root = os.path.abspath(os.path.join(os.path.dirname(__file__), ".."))
+    success = run_test(root)
+    exit_with_result(success, "logger logunit cap", "logger logunit cap")
diff --git a/test/run.sh b/test/run.sh
index 2e00391..3ff441e 100755
--- a/test/run.sh
+++ b/test/run.sh
@@ -148,6 +148,7 @@ TESTS=(
     "test/buffer_vsnprintf.py"
     "test/logunit_vsnprintf.py"
     "test/logger_thread_init.py"
+    "test/logger_unbounded_logunit.py"
     "test/pubsub_long_name.py"
     "test/pubsub_large_message.py"
     "test/transaction_forbid.py"