List IP addresses on startup

main.c

@@ -10,6 +10,11 @@
 #include <fcntl.h>
 #include <signal.h>
 
+#include <arpa/inet.h>
+#include <ifaddrs.h>
+#include <netdb.h>
+#include <sys/socket.h>
+
 #include <linux/limits.h>
 
 #include <microhttpd.h>
@@ -311,7 +316,44 @@ void init_signal_handlers(void) {
   if(sigaction(SIGPIPE, &sa, NULL) == -1) {
     LOG(LVL_ERR, "sigaction [SIGPIPE] failed: %s", strerror(errno));
   }
+}
 
+void print_addresses(void) {
+  struct ifaddrs *ifaddr, *ifa;
+  int family, s;
+  char host[INET6_ADDRSTRLEN];
+
+  if(getifaddrs(&ifaddr) == -1) {
+    LOG(LVL_ERR, "getifaddrs failed: %s", strerror(errno));
+    return;
+  }
+
+  for(ifa = ifaddr; ifa != NULL; ifa = ifa->ifa_next) {
+    if(ifa->ifa_addr == NULL) {
+      continue;
+    }
+
+    family = ifa->ifa_addr->sa_family;
+
+    if(family == AF_INET || family == AF_INET6) {
+      s = getnameinfo(ifa->ifa_addr,
+                      (family == AF_INET) ? sizeof(struct sockaddr_in)
+                                          : sizeof(struct sockaddr_in6),
+                      host,
+                      INET6_ADDRSTRLEN,
+                      NULL, 0,
+                      NI_NUMERICHOST);
+
+      if(s != 0) {
+        LOG(LVL_ERR, "getnameinfo failed: %s", gai_strerror(s));
+        continue;
+      }
+
+      LOG(LVL_INFO, "%-8s: %s", ifa->ifa_name, host);
+    }
+  }
+
+  freeifaddrs(ifaddr);
 }
 
 int main(int argc, char ** argv) {
@@ -419,6 +461,9 @@ int main(int argc, char ** argv) {
     return EXIT_FAILURE;
   }
 
+  LOG(LVL_INFO, "Startup successful. Here are the IP addresses for this computer:");
+  print_addresses();
+
   while(running) {
     sleep(60);
   }