feat: Add new methods to `say` for FFI use cases

This patch helps us create and write to non-default
loggers provided by `say.h`. We'll use this mainly
for audit log in picodata.

NO_DOC=internal
NO_TEST=internal
NO_CHANGELOG=internal

extra/exports

@@ -657,3 +657,9 @@ coio_write_timeout
 authenticate
 user_auth_method_name
 port_c_create
+
+# picodata audit log
+log_create
+log_destroy
+log_new
+log_say

src/lib/core/say.c

@@ -660,6 +660,12 @@ log_syslog_init(struct log *log, const char *init_str)
 	return 0;
 }
 
+struct log *
+log_new(void)
+{
+	return xmalloc(sizeof(struct log));
+}
+
 /**
  * Initialize logging subsystem to use in daemon mode.
  */
@@ -1401,6 +1407,18 @@ log_vsay(struct log *log, int level, bool check_level, const char *module,
 	return total;
 }
 
+int
+log_say(struct log *log, int level, const char *filename,
+	int line, const char *error, const char *format, ...)
+{
+	va_list ap;
+	va_start(ap, format);
+	int total = log_vsay(log, level, true, NULL, filename, line, error,
+			     format, ap);
+	va_end(ap);
+	return total;
+}
+
 void
 say_set_stderr_callback(say_stderr_callback_t before,
 			say_stderr_callback_t after)

src/lib/core/say.h

@@ -186,6 +186,16 @@ struct log {
 	struct rlist in_log_list;
 };
 
+/**
+ * Allocate a new uninitialized log object.
+ * To initialize the object one must call log_create()
+ * before doing log_say(). To deallocate the object use
+ * log_destroy() and free().
+ * @return pointer to log object (allocation failure is fatal)
+ */
+struct log *
+log_new(void);
+
 /**
  * Create a new log object.
  * @param log		log to initialize
@@ -207,17 +217,9 @@ log_vsay(struct log *log, int level, bool check_level, const char *module,
 	 va_list ap);
 
 /** Perform log write. */
-static inline int
+int
 log_say(struct log *log, int level, const char *filename,
-	int line, const char *error, const char *format, ...)
-{
-	va_list ap;
-	va_start(ap, format);
-	int total = log_vsay(log, level, true, NULL, filename, line, error,
-			     format, ap);
-	va_end(ap);
-	return total;
-}
+	int line, const char *error, const char *format, ...);
 
 /**
  * Default logger type info.