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Re: [PATCH] migration: fix stringop-truncation warning
From: |
Paolo Bonzini |
Subject: |
Re: [PATCH] migration: fix stringop-truncation warning |
Date: |
Thu, 12 Dec 2019 02:06:53 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.1 |
On 12/12/19 01:55, Richard Henderson wrote:
> On 12/11/19 6:23 AM, Paolo Bonzini wrote:
>> @@ -44,8 +44,7 @@ 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));
>> + memcpy(global_state.runstate, state, strlen(state) + 1);
>
> We should assign the strlen result to a local variable rather than compute it
> twice.
We could even strcpy since the assertion ensures it's valid, but perhaps
it's better to do nothing, since the best alternative would be
memset+strcpy, i.e. back to strncpy.
We generally are quite mindful about our uses of strncpy, but maybe we
could fold the assertion and strncpy into a qemu_strncpy function,
and/or qemu_strncpy_nonul for when you're copying into an array that
does _not_ need to be nul-terminated (so the assertion can become <=
rather than <). I'll add it to BiteSizedTasks.
Paolo