It's not useful when 0 is returned anyway, so be sure that we have a
string with length > 0, this also solves some indexing-gotchas like
"len - 1" and so on.
Also, add checked getline()'s whenever it has been forgotten and
clean up the error-messages.
This has already been suggested by Evan Gates <evan.gates@gmail.com>
and he's totally right about it.
So, what's the problem?
I wrote a testing program asshole.c with
int
main(void)
{
execl("/path/to/sbase/echo", "echo", "test");
return 0;
}
and checked the results with glibc and musl. Note that the
sentinel NULL is missing from the end of the argument list.
glibc calculates an argc of 5, musl 4 (instead of 2) and thus
mess up things anyway.
The powerful arg.h also focuses on argv instead of argc as well,
but ignoring argc completely is also the wrong way to go.
Instead, a more idiomatic approach is to check *argv only and
decrement argc on the go.
While at it, I rewrote yes(1) in an argv-centric way as well.
All audited tools have been "fixed" and each following audited
tool will receive the same treatment.
Previously, it was not possible to use
sha1sum test.c | sha1sum -c
because the program would not differenciate between an empty
argument and a non-specified argument.
Moreover, why not allow this?
sha1sum -c hashlist1 hashlist2
Digging deeper I found that using function pointers and a
modification in the crypt-backend might simplify the program
a lot by passing the argument-list to both cryptmain and
cryptcheck.
Allowing more than one list-file to be specified is also
consistent with what the other implementations support,
so we not only have simpler code, we also do not silently
break if there's a script around passing multiple files to
check.
