Re: [PATCH] get_home_path: use HOME

2016-09-20 18:35 GMT+02:00, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>:
> Rudolf Gavlas <r(dot)stu3(dot)1(at)googlemail(dot)com> writes:
>> The usage of HOME environment variable (if set) is IMO the right,
>> standard and faster way to get_home_path().
>
> Can you provide some evidence for that claim? I can believe "faster"
> but the rest sounds like wishful thinking.

1) NetBSD glob(3)
http://netbsd.gw.com/cgi-bin/man-cgi?glob+3+NetBSD-current
ENVIRONMENT
HOME If defined, used as the home directory of the current user in
tilde expansions.

2) BIND
https://nxr.netbsd.org/xref/src/external/bsd/bind/dist/bin/dig/dig.c#1765

3) less
https://nxr.netbsd.org/xref/src/external/bsd/less/dist/cmdbuf.c#1403
(https://nxr.netbsd.org/xref/src/external/bsd/less/dist/decode.c#533)

4) NetBSD sh(1)
http://netbsd.gw.com/cgi-bin/man-cgi?sh+1+NetBSD-current
ENVIRONMENT
HOME Set automatically by login(1) from the user's login directory in
the password file (passwd(5)). This environment variable also
functions as the default argument for the cd built-in.

5) bash(1) (version 4.3.39)
Shell Variables
The following variables are used by the shell. In some cases, bash
assigns a default value to a variable; these cases are noted below.
HOME The home directory of the current user; the default argument
for the cd builtin command. The value of this variable is also used
when performing tilde expansion.

6) OpenLDAP
https://nxr.netbsd.org/xref/src/external/bsd/openldap/dist/libraries/libldap/init.c#331

I've just grabbed what I have at hand, the list could go on ...

>> I work in an environment, where servers are administered by people
>> with different user names and identical uid (0).
>
> I think what you have there is an incredibly badly-designed system that
> can be expected to break outside software (eg, Postgres). If we take
> this patch, what's to stop someone from complaining that we broke *their*
> badly-designed system that abuses the HOME variable? I'm pretty hesitant
> to touch code that's worked the same way for a decade or two on such a
> basis.

I don't think this system is incredibly bad. But that's off-topic.

If you think that using the value of HOME variable as the user's home
directory is bad idea, I won't argue with that, I've already expressed
my opinion. What is the real problem here is using home directory of a
user A as a home directory for user B. That's clearly a bug and if you
want to solve it without using HOME, I am fine with that.

r.