svn commit: r272562 - head/lib/libc/stdtime

[Ian Lepore]

On Sun, 2014-10-05 at 07:29 +0000, Andrey A. Chernov wrote:
> Author: ache
> Date: Sun Oct  5 07:29:50 2014
> New Revision: 272562
> URL: https://svnweb.freebsd.org/changeset/base/272562
> 
> Log:
>   1) For %Z format, understand "UTC" name too.
>   2) Return NULL if timegm() fails, because it means we can convert
>   what we have in GMT to local time needed.
> 
> Modified:
>   head/lib/libc/stdtime/strptime.c
> 
> Modified: head/lib/libc/stdtime/strptime.c
> ==============================================================================
> --- head/lib/libc/stdtime/strptime.c	Sun Oct  5 07:27:05 2014	(r272561)
> +++ head/lib/libc/stdtime/strptime.c	Sun Oct  5 07:29:50 2014	(r272562)
> @@ -552,7 +552,8 @@ label:
>  				strncpy(zonestr, buf, cp - buf);
>  				zonestr[cp - buf] = '\0';
>  				tzset();
> -				if (0 == strcmp(zonestr, "GMT")) {
> +				if (0 == strcmp(zonestr, "GMT") ||
> +				    0 == strcmp(zonestr, "UTC")) {
>  				    *GMTp = 1;
>  				} else if (0 == strcmp(zonestr, tzname[0])) {
>  				    tm->tm_isdst = 0;
> @@ -674,6 +675,9 @@ strptime_l(const char * __restrict buf, 
>  	ret = _strptime(buf, fmt, tm, &gmt, loc);
>  	if (ret && gmt) {
>  		time_t t = timegm(tm);
> +
> +		if (t == -1)
> +			return (NULL);
>  		localtime_r(&t, tm);
>  	}
>  
> 

Using -1 as an error indicator in time conversions has drawbacks (your
change doesn't make it any better or worse, I'm just whining in
general)...

        revolution > date -ujf "%Y-%m-%dT%H:%M:%S" +%s 1970-01-01T0:0:0
        0
        revolution > date -ujf "%Y-%m-%dT%H:%M:%S" +%s 1969-12-31T23:59:58
        -2
        revolution > date -ujf "%Y-%m-%dT%H:%M:%S" +%s 1969-12-31T23:59:59
        date: nonexistent time

If timegm() and mktime() were to set errno in addition to returning -1,
strptime() (and others) could use that to see the difference between
errors and the second immediately before the epoch.  I'm not sure of the
standards-related implications of those routines setting errno though.

-- Ian