Init starting twice again

[Loic Prylli <Loic.Prylli@ens-lyon.fr>]

 > libc6 executes "init u" in postinst to tell init to re-execute, but
 > only recent versions of init support this feature.  If an old init is
 > still running (altough the new one has been installed since the last
 > reboot), the "init u" will execute boot code, trashing the filesystem.
 > 
 > The only safe way to upgrade would be to:
 > - install a recent sysvinit
 > - imperatively _REBOOT_
 > - complete the upgrade

Sorry for this misleading statement, the problem is more serious,
"init u" never works on Alpha.

I just crashed my machine, by trying it (and it is remote :-().

I just took a look at the code, there seems to be a problem in the
check_pipe function in sysvinit-2.73/src/init.c


char *Signature = "12567362";   /* Signature for re-exec fd */
[...]

int check_pipe(int fd)
{
        struct timeval t;
        fd_set s;
        char signature[8];

        FD_ZERO(&s);
        FD_SET(fd, &s);
        t.tv_sec = t.tv_usec = 0;

        if (select(fd+1, &s, NULL, NULL, &t) != 1)
                return 0;
        if (read(fd, signature, 8) != 8)
                 return 0;
        return strcmp(Signature, signature) == 0;
}

I think signature should be declared as a 9 bytes array, and the ninth 
bye shoudl be set to zero. But I am currently unable to test it :-(

Loic