On Fri, 11 Nov 2022 at 07:46, Philippe Mathieu-Daudé <phi...@linaro.org> wrote:
>
> From: Philippe Mathieu-Daudé <f4...@amsat.org>
>
> GCC 8 added a -Wstringop-truncation warning:
>
> The -Wstringop-truncation warning added in GCC 8.0 via r254630 for
> bug 81117 is specifically intended to highlight likely unintended
> uses of the strncpy function that truncate the terminating NUL
> character from the source string.
>
> Here the next line indeed unconditionally zeroes the last byte, but
> 1/ the buffer has been calloc'd, so we don't need to add an extra
> byte, and 2/ we called vduse_name_is_invalid() which checked the
> string length, so we can simply call strcpy().
>
> This fixes when using gcc (Ubuntu 9.4.0-1ubuntu1~20.04.1) 9.4.0:
>
> [42/666] Compiling C object subprojects/libvduse/libvduse.a.p/libvduse.c.o
> FAILED: subprojects/libvduse/libvduse.a.p/libvduse.c.o
> cc -m64 -mcx16 -Isubprojects/libvduse/libvduse.a.p -Isubprojects/libvduse
> -I../../subprojects/libvduse [...] -o
> subprojects/libvduse/libvduse.a.p/libvduse.c.o -c
> ../../subprojects/libvduse/libvduse.c
> In file included from /usr/include/string.h:495,
> from ../../subprojects/libvduse/libvduse.c:24:
> In function ‘strncpy’,
> inlined from ‘vduse_dev_create’ at
> ../../subprojects/libvduse/libvduse.c:1312:5:
> /usr/include/x86_64-linux-gnu/bits/string_fortified.h:106:10: error:
> ‘__builtin_strncpy’ specified bound 256 equals destination size
> [-Werror=stringop-truncation]
> 106 | return __builtin___strncpy_chk (__dest, __src, __len, __bos
> (__dest));
> |
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> cc1: all warnings being treated as errors
> ninja: build stopped: cannot make progress due to previous errors.
>
> Fixes: d9cf16c0be ("libvduse: Replace strcpy() with strncpy()")
> Suggested-by: Markus Armbruster <arm...@redhat.com>
> Signed-off-by: Philippe Mathieu-Daudé <phi...@linaro.org>
> ---
> Supersedes: <20220919192306.52729-1-f4...@amsat.org>
> Cc: Xie Yongji <xieyon...@bytedance.com>
> Cc: Kevin Wolf <kw...@redhat.com>
> ---
> subprojects/libvduse/libvduse.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
Applied to qemu.git/master.
Thanks,
Stefan
