diff --git a/src/deflatehd.cc b/src/deflatehd.cc
index 565a4790..29382da9 100644
--- a/src/deflatehd.cc
+++ b/src/deflatehd.cc
@@ -455,4 +455,15 @@ int main(int argc, char **argv) {
 
 } // namespace nghttp2
 
-int main(int argc, char **argv) { return nghttp2::main(argc, argv); }
+int main(int argc, char **argv) {
+  try {
+    return nghttp2::main(argc, argv);
+  } catch (std::bad_alloc &) {
+    fputs("Out of memory\n", stderr);
+  } catch (std::exception &x) {
+    fputs("Exception caught: ", stderr);
+    fputs(x.what(), stderr);
+    fputs("\n", stderr);
+  }
+  return EXIT_FAILURE;
+}
diff --git a/src/inflatehd.cc b/src/inflatehd.cc
index 98338bef..886c6189 100644
--- a/src/inflatehd.cc
+++ b/src/inflatehd.cc
@@ -49,6 +49,8 @@ extern "C" {
 #include "comp_helper.h"
 }
 
+namespace nghttp2 {
+
 typedef struct { int dump_header_table; } inflate_config;
 
 static inflate_config config;
@@ -275,3 +277,18 @@ int main(int argc, char **argv) {
   perform();
   return 0;
 }
+
+} // namespace nghttp2
+
+int main(int argc, char **argv) {
+  try {
+    return nghttp2::main(argc, argv);
+  } catch (std::bad_alloc &) {
+    fputs("Out of memory\n", stderr);
+  } catch (std::exception &x) {
+    fputs("Exception caught: ", stderr);
+    fputs(x.what(), stderr);
+    fputs("\n", stderr);
+  }
+  return EXIT_FAILURE;
+}
diff --git a/src/nghttp.cc b/src/nghttp.cc
index ff7db189..6582deac 100644
--- a/src/nghttp.cc
+++ b/src/nghttp.cc
@@ -2713,4 +2713,15 @@ int main(int argc, char **argv) {
 
 } // namespace nghttp2
 
-int main(int argc, char **argv) { return nghttp2::main(argc, argv); }
+int main(int argc, char **argv) {
+  try {
+    return nghttp2::main(argc, argv);
+  } catch (std::bad_alloc &) {
+    fputs("Out of memory\n", stderr);
+  } catch (std::exception &x) {
+    fputs("Exception caught: ", stderr);
+    fputs(x.what(), stderr);
+    fputs("\n", stderr);
+  }
+  return EXIT_FAILURE;
+}
diff --git a/src/nghttpd.cc b/src/nghttpd.cc
index 9c97f277..9a61509a 100644
--- a/src/nghttpd.cc
+++ b/src/nghttpd.cc
@@ -383,4 +383,15 @@ int main(int argc, char **argv) {
 
 } // namespace nghttp2
 
-int main(int argc, char **argv) { return nghttp2::main(argc, argv); }
+int main(int argc, char **argv) {
+  try {
+    return nghttp2::main(argc, argv);
+  } catch (std::bad_alloc &) {
+    fputs("Out of memory\n", stderr);
+  } catch (std::exception &x) {
+    fputs("Exception caught: ", stderr);
+    fputs(x.what(), stderr);
+    fputs("\n", stderr);
+  }
+  return EXIT_FAILURE;
+}
diff --git a/src/shrpx.cc b/src/shrpx.cc
index 831fc124..82d1a75b 100644
--- a/src/shrpx.cc
+++ b/src/shrpx.cc
@@ -2551,4 +2551,15 @@ int main(int argc, char **argv) {
 
 } // namespace shrpx
 
-int main(int argc, char **argv) { return shrpx::main(argc, argv); }
+int main(int argc, char **argv) {
+  try {
+    return shrpx::main(argc, argv);
+  } catch (std::bad_alloc &) {
+    fputs("Out of memory\n", stderr);
+  } catch (std::exception &x) {
+    fputs("Exception caught: ", stderr);
+    fputs(x.what(), stderr);
+    fputs("\n", stderr);
+  }
+  return EXIT_FAILURE;
+}
diff --git a/src/shrpx_log.h b/src/shrpx_log.h
index 33336913..d08f1bec 100644
--- a/src/shrpx_log.h
+++ b/src/shrpx_log.h
@@ -37,48 +37,51 @@
 #include "shrpx_log_config.h"
 #include "ssl.h"
 
-namespace shrpx {
-
-class Downstream;
-
 #define ENABLE_LOG 1
 
-#define LOG_ENABLED(SEVERITY) (ENABLE_LOG && Log::log_enabled(SEVERITY))
+#define LOG_ENABLED(SEVERITY) (ENABLE_LOG && shrpx::Log::log_enabled(SEVERITY))
 
-#define LOG(SEVERITY) Log(SEVERITY, __FILE__, __LINE__)
+#define LOG(SEVERITY) shrpx::Log(SEVERITY, __FILE__, __LINE__)
 
 // Listener log
 #define LLOG(SEVERITY, LISTEN)                                                 \
-  (Log(SEVERITY, __FILE__, __LINE__) << "[LISTEN:" << LISTEN << "] ")
+  (shrpx::Log(SEVERITY, __FILE__, __LINE__) << "[LISTEN:" << LISTEN << "] ")
 
 // Worker log
 #define WLOG(SEVERITY, WORKER)                                                 \
-  (Log(SEVERITY, __FILE__, __LINE__) << "[WORKER:" << WORKER << "] ")
+  (shrpx::Log(SEVERITY, __FILE__, __LINE__) << "[WORKER:" << WORKER << "] ")
 
 // ClientHandler log
 #define CLOG(SEVERITY, CLIENT_HANDLER)                                         \
-  (Log(SEVERITY, __FILE__, __LINE__) << "[CLIENT_HANDLER:" << CLIENT_HANDLER   \
-                                     << "] ")
+  (shrpx::Log(SEVERITY, __FILE__, __LINE__)                                    \
+   << "[CLIENT_HANDLER:" << CLIENT_HANDLER << "] ")
 
 // Upstream log
 #define ULOG(SEVERITY, UPSTREAM)                                               \
-  (Log(SEVERITY, __FILE__, __LINE__) << "[UPSTREAM:" << UPSTREAM << "] ")
+  (shrpx::Log(SEVERITY, __FILE__, __LINE__) << "[UPSTREAM:" << UPSTREAM        \
+                                            << "]"                             \
+                                               " ")
 
 // Downstream log
 #define DLOG(SEVERITY, DOWNSTREAM)                                             \
-  (Log(SEVERITY, __FILE__, __LINE__) << "[DOWNSTREAM:" << DOWNSTREAM << "] ")
+  (shrpx::Log(SEVERITY, __FILE__, __LINE__) << "[DOWNSTREAM:" << DOWNSTREAM    \
+                                            << "] ")
 
 // Downstream connection log
 #define DCLOG(SEVERITY, DCONN)                                                 \
-  (Log(SEVERITY, __FILE__, __LINE__) << "[DCONN:" << DCONN << "] ")
+  (shrpx::Log(SEVERITY, __FILE__, __LINE__) << "[DCONN:" << DCONN << "] ")
 
 // Downstream HTTP2 session log
 #define SSLOG(SEVERITY, HTTP2)                                                 \
-  (Log(SEVERITY, __FILE__, __LINE__) << "[DHTTP2:" << HTTP2 << "] ")
+  (shrpx::Log(SEVERITY, __FILE__, __LINE__) << "[DHTTP2:" << HTTP2 << "] ")
 
 // Memcached connection log
 #define MCLOG(SEVERITY, MCONN)                                                 \
-  (Log(SEVERITY, __FILE__, __LINE__) << "[MCONN:" << MCONN << "] ")
+  (shrpx::Log(SEVERITY, __FILE__, __LINE__) << "[MCONN:" << MCONN << "] ")
+
+namespace shrpx {
+
+class Downstream;
 
 enum SeverityLevel { INFO, NOTICE, WARN, ERROR, FATAL };