Journal-remote: modernize source_free() and fix memleak (#36430)

- modernize source_free().
- fix memleak introduced by cfaf78001c. Fixes CID#1591182.

src/journal-remote/journal-remote-main.c

@@ -186,24 +186,22 @@ static int build_accept_encoding(char **ret) {
 }
 
 static int request_meta(void **connection_cls, int fd, char *hostname) {
-        RemoteSource *source;
-        Writer *writer;
         int r;
 
         assert(connection_cls);
-        if (*connection_cls)
-                return 0;
 
+        if (*connection_cls)
+                return 0; /* already assigned. */
+
+        Writer *writer;
         r = journal_remote_get_writer(journal_remote_server_global, hostname, &writer);
         if (r < 0)
                 return log_warning_errno(r, "Failed to get writer for source %s: %m",
                                          hostname);
 
-        source = source_new(fd, true, hostname, writer);
-        if (!source) {
-                writer_unref(writer);
+        _cleanup_(source_freep) RemoteSource *source = source_new(fd, true, hostname, writer);
+        if (!source)
                 return log_oom();
-        }
 
         log_debug("Added RemoteSource as connection metadata %p", source);
 
@@ -212,7 +210,7 @@ static int request_meta(void **connection_cls, int fd, char *hostname) {
                 return log_oom();
 
         source->compression = COMPRESSION_NONE;
-        *connection_cls = source;
+        *connection_cls = TAKE_PTR(source);
         return 0;
 }
 

src/journal-remote/journal-remote-parse.c

@@ -6,20 +6,20 @@
 #include "parse-util.h"
 #include "string-util.h"
 
-void source_free(RemoteSource *source) {
+RemoteSource* source_free(RemoteSource *source) {
         if (!source)
-                return;
+                return NULL;
 
         journal_importer_cleanup(&source->importer);
 
-        log_debug("Writer ref count %u", source->writer->n_ref);
+        log_trace("Writer ref count %u", source->writer->n_ref);
         writer_unref(source->writer);
 
         sd_event_source_unref(source->event);
         sd_event_source_unref(source->buffer_event);
 
         free(source->encoding);
-        free(source);
+        return mfree(source);
 }
 
 /**

src/journal-remote/journal-remote-parse.h

@@ -19,5 +19,6 @@ typedef struct RemoteSource {
 } RemoteSource;
 
 RemoteSource* source_new(int fd, bool passive_fd, char *name, Writer *writer);
-void source_free(RemoteSource *source);
+RemoteSource* source_free(RemoteSource *source);
+DEFINE_TRIVIAL_CLEANUP_FUNC(RemoteSource*, source_free);
 int process_source(RemoteSource *source, JournalFileFlags file_flags);