Hi, On Thu, Jun 07, 2018 at 09:47:18AM +0530, Viresh Kumar wrote: > +Greg/Alex, > > @Fegguang/build-bot: I do see mention of Greg and /me in your initial email's > body saying TO: Viresh, CC: Greg, but I don't see any of us getting cc'd in your > email. Bug ? > > On 06-06-18, 14:26, Steven Rostedt wrote: > > On Wed, 6 Jun 2018 16:26:00 +0200 > > Johan Hovold <johan@xxxxxxxxxx> wrote: > > > > > Looks like the greybus code above is working as intended by checking for > > > unterminated string after the strncpy, even if this does now triggers > > > the truncation warning. > > So why exactly are we generating a warning here ? Is it because it is possible > that the first n bytes of src may not have the null terminating byte and the > dest may not be null terminated eventually ? > > Maybe I should just use memcpy here then ? > I think if the destination is not a null terminated string (If I understand your description below), memcpy can be used to get rid of such warning. The warning makes sense in general as explained in mannual. Thanks! > But AFAIR, I used strncpy() specifically because it also sets all the remaining > bytes after the null terminating byte with the null terminating byte. And so it > is pretty easy for me to check if the final string is null terminated by > checking [max - 1] byte against '\0', which the code is doing right now. > > I am not sure what would the best way to get around this incorrect-warning. > > And I am wondering on why buildbot reported the warning only for two instances > in that file, while I have done the same thing at 4 places. > > > Ah, yes I now see that. Thanks for pointing it out. But perhaps it > > should also add the "- 1" to the strncpy() so that gcc doesn't think > > it's a mistake. > > The src string is passed on from a firmware entity and we need to make sure the > protocol (greybus) is implemented properly by the other end. For example, in the > current case if the firmware sends "HELLOWORLD", its an error as it should have > sent "HELLWORLD\0". But with what you are saying we will forcefully make dest as > "HELLWORLD\0", which wouldn't be the right thing to do as we will miss the bug > present in firmware. > > -- > viresh -- Thanks, Changbin Du -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
