On 21/09/2020 22.39, Cleber Rosa wrote:
> On Fri, Sep 18, 2020 at 12:34:27PM +0200, 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 a strncpy here - the size is already
>> checked with the assert() statement right in front of it. To silence the
>> warning, simply replace it with our strpadcpy() function.
>>
>> Suggested-by: Philippe Mathieu-Daudé <phi...@redhat.com> (two years ago)
>> Reviewed-by: Philippe Mathieu-Daudé <phi...@redhat.com>
>> 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..a33947ca32 100644
>> --- a/migration/global_state.c
>> +++ b/migration/global_state.c
>> @@ -44,8 +44,8 @@ void global_state_store_running(void)
>> {
>> const char *state = RunState_str(RUN_STATE_RUNNING);
>> assert(strlen(state) < sizeof(global_state.runstate));
>> - strncpy((char *)global_state.runstate,
>> - state, sizeof(global_state.runstate));
>> + strpadcpy((char *)global_state.runstate, sizeof(global_state.runstate),
>> + state, '\0');
>> }
>>
>> bool global_state_received(void)
>> --
>> 2.18.2
>>
>>
>
> Hi Thomas,
>
> FIY, I couldn't reproduce the complaint from GCC. I've tested it on focal,
> "gcc (Ubuntu 9.3.0-10ubuntu2) 9.3.0", with QEMU 5df6c87e8.Hi Cleber, I've hit the error here: https://travis-ci.com/github/huth/qemu/jobs/385871010#L2930 It seems to use the very same compiler version as you did, so that's kind of weird... Maybe it's related to the other compiler flags, either --enable-gprof, --enable-gcov or --disable-pie ? Thomas
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