From d010467ac3189f7d40bcce09f9daa6bc879866cd Mon Sep 17 00:00:00 2001
From: Kefu Chai <kefu.chai@scylladb.com>
Date: Sun, 6 Oct 2024 20:39:09 +0800
Subject: [PATCH] dns: use undeprecated c-ares API

c-ares marked `ares_process()` deprecated in 1.28.1

in this change, we use `ares_process_fd()` in favor of the deprecated
`ares_process()`.

Refs #2197
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
---
 src/net/dns.cc | 42 +++++++++++++++++++++---------------------
 1 file changed, 21 insertions(+), 21 deletions(-)

diff --git a/src/net/dns.cc b/src/net/dns.cc
index 9984502e77..ba6f4db145 100644
--- a/src/net/dns.cc
+++ b/src/net/dns.cc
@@ -595,30 +595,28 @@ dns_resolver::impl::end_call() {
 void
 dns_resolver::impl::poll_sockets() {
     fd_set readers, writers;
-    int n = 0;
+    bool processed = false;
 
     dns_log.trace("Poll sockets");
 
-    do {
+    for (;;) {
         // Retrieve the set of file descriptors that the library wants us to monitor.
         FD_ZERO(&readers);
         FD_ZERO(&writers);
 
-        n = ares_fds(_channel, &readers, &writers);
+        int nr_fds = ares_fds(_channel, &readers, &writers);
 
-        dns_log.trace("ares_fds: {}", n);
+        dns_log.trace("ares_fds: {}", nr_fds);
 
-        if (n == 0) {
+        if (nr_fds == 0) {
             break;
         }
 
-        n = 0;
+        int n = 0;
 
-        for (auto & p : _sockets) {
-            auto & e = p.second;
-            auto fd = p.first;
-            auto r = FD_ISSET(p.first, &readers);
-            auto w = FD_ISSET(p.first, &writers);
+        for (auto& [fd, e] : _sockets) {
+            auto r = FD_ISSET(fd, &readers);
+            auto w = FD_ISSET(fd, &writers);
             auto ra = e.avail & POLLIN;
             auto wa = e.avail & POLLOUT;
 
@@ -626,19 +624,21 @@ dns_resolver::impl::poll_sockets() {
                             (w ? "w" : ""), (ra ? "r" : ""),
                             (wa ? "w" : ""));
 
-            if (!wa) {
-                FD_CLR(fd, &writers);
-            }
-            if (!ra) {
-                FD_CLR(fd, &readers);
-            }
-            if (FD_ISSET(fd, &writers) || FD_ISSET(fd, &readers)) {
+            ares_socket_t read_fd = r && ra ? fd : ARES_SOCKET_BAD;
+            ares_socket_t write_fd = w && wa ? fd : ARES_SOCKET_BAD;
+            if (read_fd != ARES_SOCKET_BAD || write_fd != ARES_SOCKET_BAD) {
+                ares_process_fd(_channel, read_fd, write_fd);
                 ++n;
             }
         }
-
-        ares_process(_channel, &readers, &writers);
-    } while (n != 0);
+        if (n == 0) {
+          break;
+        }
+        processed = true;
+    }
+    if (!processed) {
+      ares_process_fd(_channel, ARES_SOCKET_BAD, ARES_SOCKET_BAD);
+    }
 }
 
 dns_resolver::srv_records