From e4f6e956abdca1b7f538845dae79e5afb708e2df Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Mon, 22 Nov 2021 18:29:17 +0100
Subject: [PATCH] resolved: clean up manager_write_resolv_conf() a bit

Let's downgrade log messages which are not fatal for the service to
LOG_WARNING.

And let's simplify clean-up by using _cleanup_(unlink_and_freep).

(cherry picked from commit e2ef1e9aea24d89d1e92fa4675ddc330029b48bf)

Conflict:NA
Reference:https://github.com/systemd/systemd/commit/e4f6e956abdca1b7f538845dae79e5afb708e2df
---
 src/resolve/resolved-resolv-conf.c | 41 +++++++++++-------------------
 1 file changed, 15 insertions(+), 26 deletions(-)

diff --git a/src/resolve/resolved-resolv-conf.c b/src/resolve/resolved-resolv-conf.c
index d5a77605a8..100894d6b2 100644
--- a/src/resolve/resolved-resolv-conf.c
+++ b/src/resolve/resolved-resolv-conf.c
@@ -330,7 +330,7 @@ static int write_stub_resolv_conf_contents(FILE *f, OrderedSet *dns, OrderedSet
 
 int manager_write_resolv_conf(Manager *m) {
         _cleanup_ordered_set_free_ OrderedSet *dns = NULL, *domains = NULL;
-        _cleanup_free_ char *temp_path_uplink = NULL, *temp_path_stub = NULL;
+        _cleanup_(unlink_and_freep) char *temp_path_uplink = NULL, *temp_path_stub = NULL;
         _cleanup_fclose_ FILE *f_uplink = NULL, *f_stub = NULL;
         int r;
 
@@ -342,60 +342,49 @@ int manager_write_resolv_conf(Manager *m) {
         /* Add the full list to a set, to filter out duplicates */
         r = manager_compile_dns_servers(m, &dns);
         if (r < 0)
-                return log_warning_errno(r, "Failed to compile list of DNS servers: %m");
+                return log_warning_errno(r, "Failed to compile list of DNS servers, ignoring: %m");
 
         r = manager_compile_search_domains(m, &domains, false);
         if (r < 0)
-                return log_warning_errno(r, "Failed to compile list of search domains: %m");
+                return log_warning_errno(r, "Failed to compile list of search domains, ignoring: %m");
 
         r = fopen_temporary_label(PRIVATE_UPLINK_RESOLV_CONF, PRIVATE_UPLINK_RESOLV_CONF, &f_uplink, &temp_path_uplink);
         if (r < 0)
-                return log_warning_errno(r, "Failed to open new %s for writing: %m", PRIVATE_UPLINK_RESOLV_CONF);
+                return log_warning_errno(r, "Failed to open new %s for writing, ignoring: %m", PRIVATE_UPLINK_RESOLV_CONF);
 
         (void) fchmod(fileno(f_uplink), 0644);
 
         r = write_uplink_resolv_conf_contents(f_uplink, dns, domains);
-        if (r < 0) {
-                log_error_errno(r, "Failed to write new %s: %m", PRIVATE_UPLINK_RESOLV_CONF);
-                goto fail;
-        }
+        if (r < 0)
+                return log_warning_errno(r, "Failed to write new %s, ignoring: %m", PRIVATE_UPLINK_RESOLV_CONF);
 
         if (m->dns_stub_listener_mode != DNS_STUB_LISTENER_NO) {
                 r = fopen_temporary_label(PRIVATE_STUB_RESOLV_CONF, PRIVATE_STUB_RESOLV_CONF, &f_stub, &temp_path_stub);
-                if (r < 0) {
-                        log_warning_errno(r, "Failed to open new %s for writing: %m", PRIVATE_STUB_RESOLV_CONF);
-                        goto fail;
-                }
+                if (r < 0)
+                        return log_warning_errno(r, "Failed to open new %s for writing, ignoring: %m", PRIVATE_STUB_RESOLV_CONF);
 
                 (void) fchmod(fileno(f_stub), 0644);
 
                 r = write_stub_resolv_conf_contents(f_stub, dns, domains);
-                if (r < 0) {
-                        log_error_errno(r, "Failed to write new %s: %m", PRIVATE_STUB_RESOLV_CONF);
-                        goto fail;
-                }
+                if (r < 0)
+                        return log_warning_errno(r, "Failed to write new %s, ignoring: %m", PRIVATE_STUB_RESOLV_CONF);
 
                 r = conservative_rename(temp_path_stub, PRIVATE_STUB_RESOLV_CONF);
                 if (r < 0)
-                        log_error_errno(r, "Failed to move new %s into place: %m", PRIVATE_STUB_RESOLV_CONF);
+                        log_warning_errno(r, "Failed to move new %s into place, ignoring: %m", PRIVATE_STUB_RESOLV_CONF);
 
+                temp_path_stub = mfree(temp_path_stub); /* free the string explicitly, so that we don't unlink anymore */
         } else {
                 r = symlink_atomic_label(basename(PRIVATE_UPLINK_RESOLV_CONF), PRIVATE_STUB_RESOLV_CONF);
                 if (r < 0)
-                        log_error_errno(r, "Failed to symlink %s: %m", PRIVATE_STUB_RESOLV_CONF);
+                        log_warning_errno(r, "Failed to symlink %s, ignoring: %m", PRIVATE_STUB_RESOLV_CONF);
         }
 
         r = conservative_rename(temp_path_uplink, PRIVATE_UPLINK_RESOLV_CONF);
         if (r < 0)
-                log_error_errno(r, "Failed to move new %s into place: %m", PRIVATE_UPLINK_RESOLV_CONF);
-
- fail:
-        if (r < 0) {
-                /* Something went wrong, perform cleanup... */
-                (void) unlink(temp_path_uplink);
-                (void) unlink(temp_path_stub);
-        }
+                log_warning_errno(r, "Failed to move new %s into place: %m", PRIVATE_UPLINK_RESOLV_CONF);
 
+        temp_path_uplink = mfree(temp_path_uplink); /* free the string explicitly, so that we don't unlink anymore */
         return r;
 }
 
-- 
2.33.0