Re: pgsql: Disallow newlines in parameter values to be set in ALTER SYSTEM.

On Tue, Apr 5, 2016 at 1:05 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> Disallow newlines in parameter values to be set in ALTER SYSTEM.
>

it's also fixed problem with setting parameter to ''. Before

alter system SET shared_preload_libraries = '';

produced wrong postgresql.auto.conf and the only way was to use RESET

alter system RESET shared_preload_libraries;

> As noted by Julian Schauder in bug #14063, the configuration-file parser
> doesn't support embedded newlines in string literals. While there might
> someday be a good reason to remove that restriction, there doesn't seem
> to be one right now. However, ALTER SYSTEM SET could accept strings
> containing newlines, since many of the variable-specific value-checking
> routines would just see a newline as whitespace. This led to writing a
> postgresql.auto.conf file that was broken and had to be removed manually.
>
> Pending a reason to work harder, just throw an error if someone tries this.
>
> In passing, fix several places in the ALTER SYSTEM logic that failed to
> provide an errcode() for an ereport(), and thus would falsely log the
> failure as an internal XX000 error.
>
> Back-patch to 9.4 where ALTER SYSTEM was introduced.
>
> Branch
> ------
> REL9_5_STABLE
>
> Details
> -------
>
> http://git.postgresql.org/pg/commitdiff/f3d17491c49362b78da0c1a5b0691821dcc8c435
>
> Modified Files
> --------------
> src/backend/utils/misc/guc.c | 23 ++++++++++++++++++++---
> 1 file changed, 20 insertions(+), 3 deletions(-)
>
>
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