From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44355) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fLKI1-0000fT-9Y for qemu-devel@nongnu.org; Tue, 22 May 2018 23:18:14 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fLKI0-00088S-Fs for qemu-devel@nongnu.org; Tue, 22 May 2018 23:18:13 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:60378 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fLKI0-00088D-Az for qemu-devel@nongnu.org; Tue, 22 May 2018 23:18:12 -0400 From: Peter Xu Date: Wed, 23 May 2018 11:18:04 +0800 Message-Id: <20180523031805.27101-2-peterx@redhat.com> In-Reply-To: <20180523031805.27101-1-peterx@redhat.com> References: <20180523031805.27101-1-peterx@redhat.com> Subject: [Qemu-devel] [PATCH v3 1/2] qemu-error: introduce {error|warn}_report_once List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: "Michael S . Tsirkin" , Markus Armbruster , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , peterx@redhat.com, Jason Wang I stole the printk_once() macro. I always wanted to be able to print some error directly if there is a buffer to dump, however we can't use error_report() where the code path can be triggered by DDOS attack. To avoid that, we can introduce a print-once-like function for it. Meanwhile, we also introduce the corresponding helper for warn_report(). CC: Markus Armbruster Signed-off-by: Peter Xu --- include/qemu/error-report.h | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/include/qemu/error-report.h b/include/qemu/error-report.h index e1c8ae1a52..3e6e84801f 100644 --- a/include/qemu/error-report.h +++ b/include/qemu/error-report.h @@ -44,6 +44,32 @@ void error_report(const char *fmt, ...) GCC_FMT_ATTR(1, 2); void warn_report(const char *fmt, ...) GCC_FMT_ATTR(1, 2); void info_report(const char *fmt, ...) GCC_FMT_ATTR(1, 2); +/* Similar to error_report(), but it only prints the message once. */ +#define error_report_once(fmt, ...) \ + ({ \ + static bool __print_once; \ + bool __ret_print_once = !__print_once; \ + \ + if (!__print_once) { \ + __print_once = true; \ + error_report(fmt, ##__VA_ARGS__); \ + } \ + unlikely(__ret_print_once); \ + }) + +/* Similar to warn_report(), but it only prints the message once. */ +#define warn_report_once(fmt, ...) \ + ({ \ + static bool __print_once; \ + bool __ret_print_once = !__print_once; \ + \ + if (!__print_once) { \ + __print_once = true; \ + warn_report(fmt, ##__VA_ARGS__); \ + } \ + unlikely(__ret_print_once); \ + }) + const char *error_get_progname(void); extern bool enable_timestamp_msg; -- 2.17.0