CVS commit: src/lib/libutil

["Robert Elz" <kre%netbsd.org@localhost>]

Module Name:    src
Committed By:   kre
Date:           Mon Oct 19 15:08:17 UTC 2020

Modified Files:
        src/lib/libutil: parsedate.y

Log Message:
For touch -d (which uses parsedate()) POSIX specifies that the
ISO-8601 format yyyy-mm-ddTHH:MM:SS[radix_and+frac][Z]
be accepted.

We didn't handle that, as in parsedate(), 'T' represents the
military timezone designator, not a padding separator between
date & time as POSIX specified it.

The way parsedate() is written, fixing this in the grammar/lexer
would be hard without deleting support for T as a zone indicator
(it is *my* timezone!).

So, instead of doing that, parse an ISO-8901 string which occurs
right at the start of the input (not even any preceding white space)
by hand, before invoking the grammar, and so not involving the lexer.
This is sufficient to make touch -d conform.

After doing that, we still need to allow earlier valid inputs,
where an ISO-8601 format (using space as the separator, but without
the 'Z' (Zulu, or UTC) suffix) followed by an arbitrary timezone
designation, and other modifiers (eg: "+5 minutes" work.  So we
call the grammar on whatever is left of the input after the 8601
string has been consumed.   This all "just works" with one exception,
a format like "yyyy-mm-dd hh:mm:ss +0700" would have the grammar parse
just "+0700" which by itself would be meaningless, and so wasn't
handled.    Add a grammar rule & processing to Handle it.

Also note that while POSIX specifies "at least 4" digits in the YYYY
field, we implement "at least one" so years from 0-999 continue to be
parsed as they always have (nb: these were, and continue to be, treated
as absolute year numbers, year 10 is year 10, not 2010).  Years > 2 billion
(give or take) cannot be represented in the tm_year field of a struct tm,
so there's a limit on the max number of digits as well.


To generate a diff of this commit:
cvs rdiff -u -r1.33 -r1.34 src/lib/libutil/parsedate.y

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.