On 17/09/20 08:30, Thomas Huth wrote:
> On 16/09/2020 19.19, Thomas Huth wrote:
>> GCC 9.3.0 on Ubuntu complains:
>>
>> In file included from /usr/include/string.h:495,
>> from /home/travis/build/huth/qemu/include/qemu/osdep.h:87,
>> from ../migration/global_state.c:13:
>> In function ‘strncpy’,
>> inlined from ‘global_state_store_running’ at
>> ../migration/global_state.c:47:5:
>> /usr/include/x86_64-linux-gnu/bits/string_fortified.h:106:10: error:
>> ‘__builtin_strncpy’ specified bound 100 equals destination size
>> [-Werror=stringop-truncation]
>> 106 | return __builtin___strncpy_chk (__dest, __src, __len, __bos
>> (__dest));
>> |
>> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>
>> ... but we apparently really want to do the strncpy here. Silence the
>> warning with QEMU_NONSTRING.
>>
>> Signed-off-by: Thomas Huth <th...@redhat.com>
>> ---
>> migration/global_state.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/migration/global_state.c b/migration/global_state.c
>> index 25311479a4..f1355d7d97 100644
>> --- a/migration/global_state.c
>> +++ b/migration/global_state.c
>> @@ -43,9 +43,9 @@ int global_state_store(void)
>> void global_state_store_running(void)
>> {
>> const char *state = RunState_str(RUN_STATE_RUNNING);
>> + QEMU_NONSTRING char *dest = (char *)global_state.runstate;
>> assert(strlen(state) < sizeof(global_state.runstate));
>> - strncpy((char *)global_state.runstate,
>> - state, sizeof(global_state.runstate));
>> + strncpy(dest, state, sizeof(global_state.runstate));
>> }
>
> Darn, I was sending too fast here, sorry, but seems like this does *not*
> fix the issue with GCC 9.3:
>
> https://travis-ci.com/github/huth/qemu/jobs/385871010#L2930
>
> ... so maybe we should simply switch to strpadcpy() instead?
Yes, and probably do so everywhere that strncpy is used.
Paolo
