add backup to log_reopen, suppress compiler warnings

include/cc_log.h

@@ -74,7 +74,12 @@ struct logger *log_create(char *filename, uint32_t buf_cap);
 
 void log_destroy(struct logger **logger);
 
-rstatus_i log_reopen(struct logger *logger);
+/**
+ * Reopen the log file. Optional argument backup - if left NULL, log_reopen
+ * will simply reopen the log file. If specified, log_reopen will rename the
+ * original log file to the provided backup filename, and reopen the log file.
+ */
+rstatus_i log_reopen(struct logger *logger, char *backup);
 
 /* _log_write returns true if msg written, false if skipped or failed */
 bool log_write(struct logger *logger, char *buf, uint32_t len);

include/cc_rbuf.h

@@ -50,25 +50,25 @@ struct rbuf {
 
 #define RBUF_HDR_SIZE   offsetof(struct rbuf, data)
 
-inline uint32_t
+static inline uint32_t
 get_rpos(struct rbuf *buf)
 {
     return __atomic_load_n(&(buf->rpos), __ATOMIC_RELAXED);
 }
 
-inline uint32_t
+static inline uint32_t
 get_wpos(struct rbuf *buf)
 {
     return __atomic_load_n(&(buf->wpos), __ATOMIC_RELAXED);
 }
 
-inline void
+static inline void
 set_rpos(struct rbuf *buf, uint32_t rpos)
 {
     __atomic_store_n(&(buf->rpos), rpos, __ATOMIC_RELAXED);
 }
 
-inline void
+static inline void
 set_wpos(struct rbuf *buf, uint32_t wpos)
 {
     __atomic_store_n(&(buf->wpos), wpos, __ATOMIC_RELAXED);

src/cc_debug.c

@@ -99,7 +99,7 @@ static void
 _logrotate(int signo)
 {
     log_info("received signal %d, reopen log file", signo);
-    log_reopen(dlog->logger);
+    log_reopen(dlog->logger, NULL);
 }
 
 static void

src/cc_log.c

@@ -144,10 +144,21 @@ log_destroy(struct logger **l)
 }
 
 rstatus_i
-log_reopen(struct logger *logger)
+log_reopen(struct logger *logger, char *backup)
 {
+    int ret;
+
     if (logger->fd != STDERR_FILENO && logger->fd != STDOUT_FILENO) {
         close(logger->fd);
+
+        if (backup != NULL) {
+            ret = rename(logger->name, backup);
+            if (ret < 0) {
+                log_stderr("rename old klog file '%s' to '%s' failed, ignored: "
+                           "%s", logger->name, backup, strerror(errno));
+            }
+        }
+
         logger->fd = open(logger->name, O_WRONLY | O_APPEND | O_CREAT, 0644);
         if (logger->fd < 0) {
             log_stderr("reopening log file '%s' failed, ignored: %s", logger->name,
@@ -282,13 +293,13 @@ log_flush(struct logger *logger)
     size_t buf_len;
 
     if (logger->buf == NULL) {
-        return;
+        return 0;
     }
 
     if (logger->fd < 0) {
         log_stderr("Cannot flush logger %p; invalid file descriptor", logger);
         INCR(log_metrics, log_flush_ex);
-        return;
+        return 0;
     }
 
     buf_len = rbuf_rcap(logger->buf);