[libvirt] [PATCH 3/3] m4: Work around MinGW detection of strncpy() usage

With the recent update in Fedora Rawhide, MinGW has started freaking out about our use of strncpy(): In function 'virStrncpy', inlined from 'virStrcpy' at ../../src/util/virstring.c:811:12: ../../src/util/virstring.c:789:11: error: 'strncpy' output truncated before terminating nul copying as many bytes from a string as its length [-Werror=stringop-truncation] ret = strncpy(dest, src, n); ^~~~~~~~~~~~~~~~~~~~~ ../../src/util/virstring.c: In function 'virStrcpy': ../../src/util/virstring.c:811:12: note: length computed here return virStrncpy(dest, src, strlen(src), destbytes); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ What the compiler is not detecting is that we perform proper bound checking right before calling the function, which makes our use of it perfectly safe. Signed-off-by: Andrea Bolognani <abologna(a)redhat.com&gt; --- Kind of a big hammer, so if you have a better approach in mind please don't hesitate to step forward. cfg.mk | 2 +- m4/virt-compile-warnings.m4 | 5 +++++ 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/cfg.mk b/cfg.mk index 609ae869c2..d059f803eb 100644 --- a/cfg.mk +++ b/cfg.mk @@ -1240,7 +1240,7 @@ exclude_file_name_regexp--sc_prohibit_setuid = ^src/util/virutil\.c$$ exclude_file_name_regexp--sc_prohibit_sprintf = \ ^(cfg\.mk|docs/hacking\.html\.in|.*\.stp|.*\.pl)$$ -exclude_file_name_regexp--sc_prohibit_strncpy = ^src/util/virstring\.c$$ +exclude_file_name_regexp--sc_prohibit_strncpy = ^(src/util/virstring\.c|m4/virt-compile-warnings\.m4)$$ exclude_file_name_regexp--sc_prohibit_strtol = ^examples/.*$$ diff --git a/m4/virt-compile-warnings.m4 b/m4/virt-compile-warnings.m4 index fc185aef38..7d71cf2504 100644 --- a/m4/virt-compile-warnings.m4 +++ b/m4/virt-compile-warnings.m4 @@ -243,6 +243,11 @@ AC_DEFUN([LIBVIRT_COMPILE_WARNINGS],[ wantwarn="$wantwarn -Wno-suggest-attribute=pure" wantwarn="$wantwarn -Wno-suggest-attribute=const" + # MinGW freaks out about our use of strncpy(), but we perform proper + # bound checking in our wrappers and prevent the underlying POSIX + # functions from being used directly through syntax-check + wantwarn="$wantwarn -Wno-stringop-truncation -Wno-stringop-overflow" + if test "$enable_werror" = "yes" then wantwarn="$wantwarn -Werror" -- 2.17.1