On 01/05/2019 11:44, Daniel P. Berrangé wrote: > On Wed, May 01, 2019 at 11:40:13AM +0200, Laurent Vivier wrote: >> On 01/05/2019 01:28, Alistair Francis wrote: >>> Fix this warning when building with GCC9 on Fedora 30: >>> In function ‘strncpy’, >>> inlined from ‘sys_uname’ at /home/alistair/qemu/linux-user/uname.c:94:3: >>> /usr/include/bits/string_fortified.h:106:10: error: ‘__builtin_strncpy’ >>> output may be truncated copying 64 bytes from a string of length 64 >>> [-Werror=stringop-truncation] >>> 106 | return __builtin___strncpy_chk (__dest, __src, __len, __bos >>> (__dest)); >>> | >>> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >>> >>> Signed-off-by: Alistair Francis <alistair.fran...@wdc.com> >>> --- >>> linux-user/uname.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/linux-user/uname.c b/linux-user/uname.c >>> index 313b79dbad..2fc6096a5b 100644 >>> --- a/linux-user/uname.c >>> +++ b/linux-user/uname.c >>> @@ -73,7 +73,7 @@ const char *cpu_to_uname_machine(void *cpu_env) >>> #define COPY_UTSNAME_FIELD(dest, src) \ >>> do { \ >>> /* __NEW_UTS_LEN doesn't include terminating null */ \ >>> - (void) strncpy((dest), (src), __NEW_UTS_LEN); \ >>> + (void) memcpy((dest), (src), MIN(strlen(src), __NEW_UTS_LEN)); \ >> >> You should use MIN(strlen(src) + 1, __NEW_UTS_LEN) to copy the NUL >> character if it is present and fit in __NEW_UTS_LEN. > > IMHO we shouldn't use strlen at all. I proposed fixing it using sizeof() > instead here: > > https://lists.gnu.org/archive/html/qemu-devel/2019-04/msg02154.html >
Yes, it's better. Thanks, Laurent