From 141ae823abe33276c84868927d1e2c190024f227 Mon Sep 17 00:00:00 2001
From: Andrew Noyes <andrew@weaselab.dev>
Date: Mon, 18 Aug 2025 15:57:03 -0400
Subject: [PATCH] Improve some error handling

Handle EINTR in signal handler
Handle getListenFd errors by trying the next address
---
 src/main.cpp | 33 ++++++++++++++++++++-------------
 1 file changed, 20 insertions(+), 13 deletions(-)

diff --git a/src/main.cpp b/src/main.cpp
index d1482aa..ddd4b5e 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -30,10 +30,13 @@ int shutdown_eventfd = -1;
 void signal_handler(int sig) {
   if (sig == SIGTERM || sig == SIGINT) {
     if (shutdown_eventfd != -1) {
-      uint64_t val = 1;
+      char val = 1;
       // write() is async-signal-safe per POSIX - safe to use in signal handler
-      if (write(shutdown_eventfd, &val, sizeof(val)) == -1) {
-        abort(); // Critical failure - can't signal shutdown
+      // Write single byte to avoid partial write complexity
+      while (write(shutdown_eventfd, &val, 1) == -1) {
+        if (errno != EINTR) {
+          abort(); // graceful shutdown didn't work. Let's go ungraceful.
+        }
       }
     }
   }
@@ -73,12 +76,23 @@ int getListenFd(const char *node, const char *service) {
     }
 
     int val = 1;
-    setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
+    if (setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val)) == -1) {
+      perror("setsockopt SO_REUSEADDR");
+      close(sfd);
+      continue; // Try next address
+    }
 
     // Set socket to non-blocking for graceful shutdown
     int flags = fcntl(sfd, F_GETFL, 0);
-    if (flags != -1) {
-      fcntl(sfd, F_SETFL, flags | O_NONBLOCK);
+    if (flags == -1) {
+      perror("fcntl F_GETFL");
+      close(sfd);
+      continue; // Try next address
+    }
+    if (fcntl(sfd, F_SETFL, flags | O_NONBLOCK) == -1) {
+      perror("fcntl F_SETFL");
+      close(sfd);
+      continue; // Try next address
     }
 
     if (bind(sfd, rp->ai_addr, rp->ai_addrlen) == 0) {
@@ -104,13 +118,6 @@ int getListenFd(const char *node, const char *service) {
   return sfd;
 }
 
-int getAcceptFd(int listenFd, struct sockaddr_storage *addr) {
-  // Use sockaddr_storage (not sockaddr) to handle both IPv4 and IPv6
-  socklen_t addrlen = sizeof(sockaddr_storage);
-  int fd = accept4(listenFd, (struct sockaddr *)addr, &addrlen, SOCK_NONBLOCK);
-  return fd;
-}
-
 // Since only one thread owns a connection at a time, no synchronization is
 // necessary
 // Connection ownership model: