Re: Possible regression: libpq + SSL aborts when user has no home directory

I wrote:
> Christian Kastner <debian(at)kvr(dot)at> writes:
>> Using libpq 9.0.3, when an SSL connection is attempted from a client
>> whose EUID is not in a password database, the connection fails because
>> the home directory cannot be determined. With libpq 8.4.7, everything is
>> fine.

> Hmm. Offhand I agree that that seems like an unnecessary regression.
> It should act just the same as if it could not find any of those files.
> A quick look with git blame suggests that this got broken in my
> commit 4ed4b6c54e5fab24ab2624d80e26f7546edc88ad, and I don't think
> that it was intentional.

> One small problem is that if the sslmode is "verify-ca" or
> "verify-full", failure to find the root cert file is an error,
> and that error message normally includes the pathname at which
> the cert file was sought. What shall we print if we couldn't
> identify the home directory?

Attached is an untested patch which I'd appreciate if you (or somebody
else who uses SSL connections more than I do) could test. I resolved
the last mentioned problem by printing "~/.postgresql/root.crt", which
is a bit of a Unix-ism but doesn't seem too unreasonable, and anyway we
weren't printing anything terribly useful before either. We could
change that message though if we wanted, since AFAICS the only way to
get there is pqGetHomeDirectory failure. So we could just print the
"could not get home directory" message instead. Thoughts?

regards, tom lane