From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45643) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fIW29-0001mJ-Tl for qemu-devel@nongnu.org; Tue, 15 May 2018 05:14:14 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fIW24-0006hh-Rm for qemu-devel@nongnu.org; Tue, 15 May 2018 05:14:13 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:57830 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 1fIW24-0006gJ-NV for qemu-devel@nongnu.org; Tue, 15 May 2018 05:14:08 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 7D351400BA82 for ; Tue, 15 May 2018 09:14:02 +0000 (UTC) From: Peter Xu Date: Tue, 15 May 2018 17:13:56 +0800 Message-Id: <20180515091356.24106-1-peterx@redhat.com> Subject: [Qemu-devel] [PATCH RFC] qemu-error: introduce error_report_once List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: peterx@redhat.com, Markus Armbruster 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() really quite often when there can be any DDOS attack. To avoid that, we can introduce a print-once function for it. CC: Markus Armbruster Signed-off-by: Peter Xu --- We can for sure introduce similar functions for the rest of the error_*() functions, it's just an idea to see whether we'd like it in general. --- include/qemu/error-report.h | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/include/qemu/error-report.h b/include/qemu/error-report.h index e1c8ae1a52..efebb80e2c 100644 --- a/include/qemu/error-report.h +++ b/include/qemu/error-report.h @@ -44,6 +44,18 @@ 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); +#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); \ + }) + const char *error_get_progname(void); extern bool enable_timestamp_msg; -- 2.17.0