[PATCH 8/8] wall: new applet

[Denys Vlasenko]

On Tue, Oct 27, 2009 at 10:47 AM, Peter Korsgaard <jacmet at uclibc.org> wrote:
>>>>>> "walter" == walter harms <wharms at bfs.de> writes:
>
> Hi,
>
>  >> +   int fd = argv[1] ? xopen(argv[1], O_RDONLY) : STDIN_FILENO;
>  >> +
>
>
>  walter>        i did not try; but what will happen if argc==1 ?
>  walter>        argv[1] should be undefined.
>
> No, argv is afaik guaranteed to be null terminated - E.G. access to
> argv[argc] is OK - But you can ofcourse cheat with execve and get argc
> == 0, so the below is indeed better.
>
>  walter>        perhaps this is more save
>  walter>        (argc > 1) ? xopen(argv[1], O_RDONLY) : STDIN_FILENO;

Yes, you can do

int main()
{
        static char *argv[1] = { 0 };
        execvp("busybox", argv);
        return 0;
}

but this way busybox wouldn't even call wall_main, it will segfault earlier.
--
vda