From 4d0f16d059ddb91424480d88473f7392f24aebdc Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Thu, 6 Dec 2018 11:41:03 -0300 Subject: [PATCH] perf ui helpline: Use strlcpy() as a shorter form of strncpy() + explicit set nul The strncpy() function may leave the destination string buffer unterminated, better use strlcpy() that we have a __weak fallback implementation for systems without it. In this case we are actually setting the null byte at the right place, but since we pass the buffer size as the limit to strncpy() and not it minus one, gcc ends up warning us about that, see below. So, lets just switch to the shorter form provided by strlcpy(). This fixes this warning on an Alpine Linux Edge system with gcc 8.2: ui/tui/helpline.c: In function 'tui_helpline__push': ui/tui/helpline.c:27:2: error: 'strncpy' specified bound 512 equals destination size [-Werror=stringop-truncation] strncpy(ui_helpline__current, msg, sz)[sz - 1] = '\0'; ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ cc1: all warnings being treated as errors Cc: Adrian Hunter Cc: Jiri Olsa Cc: Namhyung Kim Fixes: e6e904687949 ("perf ui: Introduce struct ui_helpline") Link: https://lkml.kernel.org/n/tip-d1wz0hjjsh19xbalw69qpytj@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/ui/tui/helpline.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/ui/tui/helpline.c b/tools/perf/ui/tui/helpline.c index 4ca799a..93d6b72 100644 --- a/tools/perf/ui/tui/helpline.c +++ b/tools/perf/ui/tui/helpline.c @@ -24,7 +24,7 @@ static void tui_helpline__push(const char *msg) SLsmg_set_color(0); SLsmg_write_nstring((char *)msg, SLtt_Screen_Cols); SLsmg_refresh(); - strncpy(ui_helpline__current, msg, sz)[sz - 1] = '\0'; + strlcpy(ui_helpline__current, msg, sz); } static int tui_helpline__show(const char *format, va_list ap) -- 2.7.4