nghttpx: Add error handling for strdup and sigaction

src/shrpx.cc

@@ -1682,6 +1682,11 @@ int main(int argc, char **argv) {
 
   for (int i = 0; i < argc; ++i) {
     mod_config()->argv[i] = strdup(argv[i]);
+    if (mod_config()->argv[i] == nullptr) {
+      auto error = errno;
+      LOG(FATAL) << "failed to copy argv: " << strerror(error);
+      exit(EXIT_FAILURE);
+    }
   }
 
   mod_config()->cwd = getcwd(nullptr, 0);

src/shrpx_signal.cc

@@ -97,8 +97,14 @@ void signal_set_handler(void (*handler)(int), Signals &&sigs) {
   struct sigaction act {};
   act.sa_handler = handler;
   sigemptyset(&act.sa_mask);
+  int rv;
   for (auto sig : sigs) {
-    sigaction(sig, &act, nullptr);
+    rv = sigaction(sig, &act, nullptr);
+    if (rv != 0) {
+      auto error = errno;
+      LOG(WARN) << "sigaction() with signal " << sig
+                << " failed: errno=" << error;
+    }
   }
 }
 } // namespace