Write directly to FILE stream in glibc printf hooks

2 files changed, 49 insertions, 35 deletions

diff --git a/src/libstrongswan/printf_hook.c b/src/libstrongswan/printf_hook.c
index 1ffe550c7..22f5d78d9 100644
--- a/src/libstrongswan/printf_hook.c
+++ b/src/libstrongswan/printf_hook.c
@@ -86,25 +86,17 @@ static printf_hook_handler_t *printf_hooks[NUM_HANDLERS];
 static int custom_print(FILE *stream, const struct printf_info *info,
 						const void *const *args)
 {
-	int written;
-	char buf[PRINTF_BUF_LEN];
 	printf_hook_spec_t spec;
 	printf_hook_handler_t *handler = printf_hooks[SPEC_TO_INDEX(info->spec)];
 	printf_hook_data_t data = {
-		.buf = buf,
-		.buflen = sizeof(buf),
+		.stream = stream,
 	};
 
 	spec.hash = info->alt;
 	spec.minus = info->left;
 	spec.width = info->width;
 
-	written = handler->hook(&data, &spec, args);
-	if (written > 0)
-	{
-		ignore_result(fwrite(buf, 1, written, stream));
-	}
-	return written;
+	return handler->hook(&data, &spec, args);
 }
 
 /**
diff --git a/src/libstrongswan/printf_hook.h b/src/libstrongswan/printf_hook.h
index a72295afd..fa11b6f9b 100644
--- a/src/libstrongswan/printf_hook.h
+++ b/src/libstrongswan/printf_hook.h
@@ -46,6 +46,29 @@ enum printf_hook_argtype_t {
 	PRINTF_HOOK_ARGTYPE_POINTER = PA_POINTER,
 };
 
+/**
+ * Data to pass to a printf hook.
+ */
+struct printf_hook_data_t {
+
+	/**
+	 * Output FILE stream
+	 */
+	FILE *stream;;
+};
+
+/**
+ * Helper macro to be used in printf hook callbacks.
+ */
+#define print_in_hook(data, fmt, ...) ({\
+	int _written = fprintf(data->stream, fmt, ##__VA_ARGS__);\
+	if (_written < 0)\
+	{\
+		_written = 0;\
+	}\
+	_written;\
+})
+
 #else
 
 #include <vstr.h>
@@ -86,23 +109,24 @@ int vstr_wrapper_vasprintf(char **str, const char *format, va_list ap);
 #define vsnprintf vstr_wrapper_vsnprintf
 #define vasprintf vstr_wrapper_vasprintf
 
-#endif
-
 /**
- * Callback function type for printf hooks.
- *
- * @param data		hook data, to pass to print_in_hook()
- * @param spec		format specifier
- * @param args		arguments array
- * @return			number of characters written
+ * Data to pass to a printf hook.
  */
-typedef int (*printf_hook_function_t)(printf_hook_data_t *data,
-									  printf_hook_spec_t *spec,
-									  const void *const *args);
+struct printf_hook_data_t {
+
+	/**
+	 * Buffer to write to
+	 */
+	char *buf;
+
+	/**
+	 * Size of the buffer
+	 */
+	size_t buflen;
+};
 
 /**
  * Helper macro to be used in printf hook callbacks.
- * buf and buflen get modified.
  */
 #define print_in_hook(data, fmt, ...) ({\
 	int _written = snprintf(data->buf, data->buflen, fmt, ##__VA_ARGS__);\
@@ -115,21 +139,19 @@ typedef int (*printf_hook_function_t)(printf_hook_data_t *data,
 	_written;\
 })
 
+#endif
+
 /**
- * Data to pass to a printf hook.
+ * Callback function type for printf hooks.
+ *
+ * @param data		hook data, to pass to print_in_hook()
+ * @param spec		format specifier
+ * @param args		arguments array
+ * @return			number of characters written
  */
-struct printf_hook_data_t {
-
-	/**
-	 * Buffer to write to
-	 */
-	char *buf;
-
-	/**
-	 * Size of the buffer
-	 */
-	size_t buflen;
-};
+typedef int (*printf_hook_function_t)(printf_hook_data_t *data,
+									  printf_hook_spec_t *spec,
+									  const void *const *args);
 
 /**
  * Properties of the format specifier